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SUSITNA HYDROELECTRIC PROJECT
1980 -81 GEOTECHNICAL REPORT
VOLUME 2
APPENDIX G - K
FINAL DRAFT
Prepared by:
[Ii ARLIS
Alaska Resources
Library &Infonnatlon Se Ie s
Anchorage,Alaska
L...--__ALASKA POWER AUTHORITY __----'
VOLUME 2
APPENDIX
G-DEVIL CANYON BORROW SITE INVESTIGATION
G,l -BORROW SITE G
H-SEISMIC REFRACTION SURVEY -1980
I -SEISMIC REFRACTION SURVEY -1981
J -AIR PHOTO INTERPRETATION
K-RESERVOIR SLOPE STABILITY
ARLIS
Alaska Resources
Library & Inform lion Scmces
Anchorage.Alaska
-
APPENDIX G
DEVIL CANYON BORROW AREA INVESTIGATION
EXPLANATION OF SELECTED SYMBOLS
STANDARD SYMBOLS
~ORGANIC MATERIAL ~COBBLES 8 BOULDERS t~/I IGNEOUS ROCK ~SANDY SILT~-""\I ~
~CLAY ~CONGLOMERATE WJ METAMORPHIC ROCK ~SILT GRADING TO
.~.I?~..SANDY SILT
~E2]II ~SANDY GRAVEL,
SILT ._,.._."SANDSTONE ICE,MASSIVE SCATTERED COBBLES
(ROCK FRAGMENT S)
LEJj SAND a MUDSTONE ~ICE -SILT EB INTERLAYEREO SANO
8 SANOY GRAVEL
0°0 GRAVEL ~LiMESTOI'IE ~ORGANIC SILT ~SILTY CLAY wfTR SAND°000
00
SAMPLER TYPE SYM BOLS
SI •••••1.4 SPLIT SPOON WITH 47#HAMMER Ts.•SHELBY TUBE
SS .14 SPLIT SPOON WITH 140 #HAMMER Tm.MODIFIED SHELBY TUBE
SI •••••2.~"SPLIT SPOON WITH 140#HAMMER Pb ••PITCHER BARREL
Sh •••••2.~"SPLIT SPOON WITH 340#HAMMER Cs .•CORE BARREL WITH SINGLE TUBE
S••••••2.0"SPLIT SPOON WITH 140#HAMMER Cd ••CORE BARREL WITH DOUBLE TUBE
S,.••.•14"SPLIT SPOON WITH 340#HAMMER Bs ••••BULK SAMPLE
Sp •••••2.~"SPLIT SPOON.PUSHED A •.••AUGER SAMPLE
Hs •••••1.4"SPliT SPOON DRIVEN WITH AIR HAMMER G.••••GRAB SAMPLE
HI •••••2.~"SPLIT SPOON DRIVEN WITH AIR HAMMER
NOTE:SAMPLER TYPES ARE EITHER NOTED ABOVE THE BORING LOG DR ADJACENT TO IT AT TH E RESPECTIVE
SAMPLE DEPTH.
TYPICAL BORING LOG
3D'TO-TOTAL DEPTH
9~
26'
SCHIST -GENERALIZED SOIL OR ROCK DESCRIPTION
SAMPLE LOCATION
SANOY SI LT
___~APPROX/~~T£STRATA CHANGE
Lillie loNoVisible Ice 13'-30'V.-ICE:,DESCRIPTION 8 CLASSIFICATION
\72'~7"O/O'8~'9PCf'28~GP (CORPS OF ENGINEERS ME:THOD;
\""
"".....UNIFIE:D ORFAA CLASSIFICATION
"TEMPERATURE,of
DRY DENSITY
WATER CONTENT
BLOWS/FOOT
SAMPLE:NvM8ER
SANDY GRAVEL
BORING NUMBER __T.H .30-1~Eltv.274.6-£LEVATIONINFEET
DATE lWILLED __10 _21.60 All Sample,S,__SAM,PLER TYPE
ORGANIC MATERIAL 0
Consid.VIsible ICt 0-7 ICE+ML"
ICE-SILT
stimate 65%VIsible Ic.
I 90,~6.2%STRATA CHANGE
"'t':.-r.~-::"'~":"'::":-::'~--...L..__7'
FROZEN GROUND
SAMPLER TyPE ....
Ss
WATER TABLE --...-.
9*
11'0.
DRILLING SYMBOLS
WD:
WL:
W5:
While Drilling
Water Level
While Sampling
A8:
TO:
After Boring
Total Depth
~Water levels indicated on the boring logs are the levels measured in the
boring at the times indicated.In pervious unfrozen soils,the indic~ted elevations
are considered to represent actual ground water conditions.In impervious ~nd
frozen soils,accurate determinations of ground water elevations cannot be obtained
within a limited period of observation and other evidence on ground water elevations
and conditions are required.
PAEPARED BY I PREPARED FOR·
EXPLANATION OF SELECTED SYMBOLS
SOILS
CLASSIFICATION AND CONSISTENCY
CLASSIFICATION:Identification and classification of the soil is accomplished in
accordance with the Unified Soi I Classification System.Normally,the grain size
distirbution determines classification of the soil.The soil is defined according to
major and minor constituents with the minor elements serving as modifiers of the
major elements.Minor soil constitutents may be added to the classification
breakdown in accordance with the particle size proportions listed below;(i .e.,
sandy si It with some gravel,trace clay).
no call -0-3%trace -3-12%some -13-30%sandy,silty,gravelly ->30%
Identification and classification of soil strata which have a significant cobble and
boulder content is based on the unified classification of the minus 3 inch fraction
augmented by a description (i.e.,cobbles and boulders)of the plus 3 inch
fraction.Where a gradation curve,which includes the plus 3 inch fraction,exists
(samples from test trenches and pits)a modifier is used to describe independently
the percentage of each of the two plus 3 inch components.If there is no gradation
curve incorporating the plus 3-inch fraction (as in auger holes),the plus 3-inch
material is described as a single component (i.e.,cobbles and boulders),and a
modifier is used to indicate the relative percentage of the plus 3-inch fraction based
on the field logs.The modifiers in each case are used as follows:
Scattered -0-40%Numerous - >40%
SOIL CONSISTENCY -CRITERIA:Soil consistency as defined below and determined
by normal field and laboratory methods applies only to non-frozen material.For
these materials,the influence of such factors as soil structure,i.e.fissure
systems,shrinkage cracks,slickensides,etc.,must be taken into consideration in
making any correlation with the consistency values listed below.In permafrost
zones,the'consistency and strength of frozen soils may vary significantly and
unexplainably with ice content,thermal regime and soi I type.
Cohesion less Soils
N*
(blows/H)Relative Density
Cohesive Soils
N*
(blows/ft)gu -(tsf)
Very Loose
Loose
Medium Dense
Dense
Very Dense
0-4
4 -10
10 -30
30 -50
>50
20%
20 to 40%
40 to 60%
60 to 80%
>80%
Very Soft
Soft
Medium
Stiff
Very Stiff
Hard
0-2
2 - 4
4 -8
8 -15
15 -30
>30
o -0.25
0.25 -0.5
0.5 -1.0
1.0 -2.0
2.0 -4.0
>4.0
*Standard Penetration "N":Blows per foot of a 140-pound hammer falling
30 inches on a 2-inch OD split-spoon except where noted.
Often the split-spoon samplers do not reach the total intended sample depth.Where
this occurs the graphic log notes a refusal (Ref.)and give an indication of the
cause of the refusal.Tight soils are indicated by a blow count value followed by a
penetration length in inches.The presense of large rock fragments is indicated by
a cobble and boulder callout following the refusal callout.In certain instances a
blow count of 100+may be listed to indicate tight soils where total sampler
penetration is possible with more than 100 blows per foot.
PREPARED BY'PREPARED FOR'
EXPLANATION OF ICE SYMBOLS
Perct-ntage of visible ice has been grouped for the purpose of designating the
amount of soil ice content.These groups have arbitrarily been set out
as follows:
0%
1%-10%
11%-20%
21%-35%
>35%
No Visible Ice
Li t tIe Visible lee
Occasional Visible Ice
Some Visible IcC'
Considerable Visible'Ice
The ice description system is bclsed on tha t rresen LeJ by K.A.Linell,and
C.W.Kaplar (1966).In this system,which is an extension of the Unified
Soil Classification System,the amount and physicdl clldracteristics of the
soil ice are accounted for.The following table is a brief summary of the
salient points of their classi£ication systel:',as ml)Jified Lll meeL the needs
of this study.
ICE DES C R I PT ION S
GROUP ICE VISIBILITY a CONTENT
SYMBOL
SUBGROUP
DESCRIPTION SYMBOL
N
v
ICE
Ice not visible
Ice visible,<50%
Ice visible,>50%
Individual layer >6"thick *
Poorly bo n ded
or 'riabl e
:No excess
Well ~~e _
bonded I Excess
I Ice
indiVIdual Ice
crystals or
inclUSions
Ice coat,n'il~
on partl cles
Random or
irre'ilu!arly
ollenled Ice
formations
Stratified or
dIstinctly oriented
ice formations
lei wi th SOil
Inclusions
Ice Without
soil Inclusions
V r
ICE +
soil type
ICE
*In some cases where thl soil is iCI poor a thin Ice layer moy be called out
by Iplcial notation on thl 1011.i e.2"iCI lenl at 7'
PREPARED BY I
lR~&I'ME
RAM CONSULTANTS,INC.
EXPLANATION OF ICE SYMBOLS
PREPARED FOA'
G.l BORROW SITE G
AUGER HOLE LOGS
SILT
GRAVEL \\'/TRACE SILT
0'
~--------4'30
ORGANIC MATERIAL
---------.5'
Scattered Cobbles,11'-23'
Boulder at 23',Refusal
r...ll.;;..;.:.;L 23 'T.D.
AH-G1
7-22-80
Sp
Sp
Sl
Sl
Sl
Sl
Sl
Sl
Sl
Sl
Sl
~'7ATER TABLE NOT Er1COUNTE~D
filII CONIULTANT',INC.
BORP'O~I ta.P Eta.G
AUGER HOLE JlJ:-Gl
Scale 1"=2'
sp
5P
51
Sl
Sl
51
Sl
51
AH-G4
7-22-80=-::rT....".;;...;;...----------O'
1 ORGANIC HATERIAL
----------0.5'
2 Seasonal Fros t .5-1.5'
53
SILTY SAND Ar-JD
SAND II/TRACE SILT
Gray-Tan________3'
54
89
SANDY GRAVEL W/TRACE
SILT
Brown to Gray,Subangular to
Subrounded
Refusal
Scattered Cobbles,6'-11'
Refusal
Refusal
Boulder at 11',Refusal
Io..llo.~-------------ll'T.D.
WATER TABLE NOT ENCOUNTERED
BC'RRc~r Jl.REA G
Jl.UGER ~CLE AH-G4
Scale 1"=2'
3.7%,130.9 Pcf.,GW-r,p
__-_.30.0
SANDY GRAVEL
Ref.,32/2"
22.0'-39.0.SeattereJ
Coi..>bles
42.0'-44.0'Cobble
Layer
44.0'-50.0'Scattered
Cobbles
L..L"--'-'-'''-L 55 .0 '
Water Table Not Encountered.T.O.
8h
Sh
Sh
I-.-'-~i-+,.......-50.0'
Sh 34,6.8%,98.7 pef.,SF
SAND WITH TRACE
c;ILT
:;RAY
52.0'-55.0'Cobble
Layer
Eleva tion 982.0'
___15.0'
Re f-.,-Cobble
12.5'Cobble
15 ..0'-22.0'Scattered to
Numerous Cobbles and
Boulders
SANDY GRAVEL
Gray
SAND WITH SOMB GRAVEL
Ai.'JD TRAC2 SILTGrayffi8ISP-SM
®lO,SP-SM
(2)9,SP-SM
®13 ..SP-8M
0.0'="'_--r-....,."...--.,---------------"ORGANIC MAT2RIAL a.s'
SILT WITH SOME ORGANICSANDTRACESAND
Gray-Bro~1 1.S'
Sh
.'.lq'I'mA'
8h 9"."''-
':.:;~::
Sh .j;!'
~:.0
8h .'::'>
:~b
~-:
Sh ·:L.~:.
'.':'"
p",......:..
Scale:1"=4
PREPARED BY'
R&M CONSULTANTS,tNC.
BORROW AREA G
AUGER HOLE AH -G9
PREPA.RED FOR:
Sp
Sp
Tm
Sh
Sh
Sh
Sh
Sh
Sh
Sh
Elevation 980.0'
0.0'~~~~"'iCO)i:R~G~A~i~J=IrcC:iMq:AiVTr:ER"RRTIAALL---0 J I
ILTY SAND WITH SOME ORGANICS
Gray Brown 1.5'
SILTY SAND
Gray
@)4,30.9%,72.7 pcf.,SM
®10,15.7%,89.6 peL,SH
~':'-:t+-~------~----6.0 '11,11.7%,94.8 pef.,SP-SM
SAND WITH TRACE SILT
GrayG06,22.9%,90.2 pef.,SP-SM
__9.0'
SAfmy GRAVEL WITE SC~TTERED TO
NUMEROUS COBBLES AND BOULDERS
Grey
1.:...:...:..,I;....L 19 .0'T.D.
Water Table Not Encountered.
PREPARED BY'
R&M CON SULTANTS.
BORROW AREA G
AUGER HOLE AH-G10·
Scale:1"=3
PREPARED FOR:
16
_______15.0'
__~5.0'
123.9 pcf.,8M
GRAVELLY SAl'JD WITH SOME
SILT
Light Gray
®51 S~1
®32,11.2%,
P no 8M
"'""-'-'-'-'-'L.J....\!:!;J --.J 1.a I
T.O.
Thermal Probe Installed to 31.0'
Water Table Not Encountered.
SAND WITH SOME SILT AND
GRAVEL
Light Gray
@ Ref.,Cobble
SILT WITH
AND TRACt:;
Browno
(2)32,14.n,119.6 peL ,SM
ORGANIC MATERIAL~r-----O.4'
SOt-tE ORGANICS
SANLJ
~~I-+-rc-...--::--------~--6.5 I
6 15,16.3%,110.0 pef.,SM
;x..,~r-T-~r------------O .0'
Sh
Sh
PREPARED BY'
BORROW AREA G
AUGER HOLE AH-Gll
RIM CONSULTANTS,INC.
PREPARE 0 FOR'
Scale;1"=3
6.8%,137.2 pef.,G~-GM
ARGILLITE
SILT WITH SOME ORGANICS
AND TRAc£:;SAND
Brown
0 9
08
~5G,7.1%,143.2 Pef .•GP-GM
0.0'
ORGANIC MATERIAL).,..,,....-0.3 I
@52.GP-GM
SANDY GRAVEL WITH TRACE
SIL'I'
1iotM~~~_Gr_a y 10.5 I
Loo=::::.L.JL....L 13 .5 'T.D.
*Blow Counts Not Available
'I'hermal Probe Installed to 13.5 ft.
Sh .
Sh'
P=40I-+-r.:-..,.-::-.,....--"..----------4.a I
5 14,SP
GRAVELLY SAJ.'JD
Gray
S11 (08,SP
\;..I.I.,~~--__------6.0'
Sri
S11
Sh
Sh
PREPARED BY I
R&M CONSULTANTS,INC.
BORROW AREA G
AUGER HOLE AH-G12
Scale·1"=3'
PREPARED FOR,
-20.0'
Gray
SANDY GRAVE.L WITH SOME
SILT
95
106 I S'Iv-SM
GRAVELLY SA1,jD lHTH
TRACE SIVf
Gray
12,GM-SM
26.5'-35.0'Scattered
Cobbles
...
..0 ...
~C?~35.0'
T.D.
Thermal Probe Installed to 33.0'
'.6.,...~'?-~~~,.%25.0
S))'/j I'1Q\35 SW-SM./·0 Y:.:;J ,
,o.·~.~.
(I':.-.0.,0.
Sh
Sh
pcf.,SW-SH
pcf.,SW-SH
-20.0'
Gray
SILT WITH SOME SANP
AND SOME TO TRACE CLAY
ORGANIC HATERIAL
Sfu~D WITH TRACE SILT AND
GRAVEL
11.5'-13.5'Scattered
Cobbles
------------13.':)'
SILT WITH SOME SAND
Gray
Gray
O.S'~------------
®13,18%,101.6 peL,S\!-SM
SAND WITH SOME ORGANICS
AND TRACE SILT
Gray
0)
*..Sh ';'.:'.;',@ 24 I 24.7%,98.G peL,SW-SM
'.::.::
~~~:...:-----------o.0'Sp ~:::~
.:..::~:
Th1:*::
1:-'.:.,...·.+......=-++--------------3.0 t
Sh '?f!:
.:":::::".:
7.0'
W.D.~
~
PREPARED BY'PREPARED FOR'
R&M CONSULTANTS,
BORROW AREA G
AUGER HOI£Alf-Gl3
Scale:1":<:3'
______-23.0'
SILT WITH SOME SAND,
SOME TO TRACE CLAY AND
TRACE GRAVEL •
GrayoG7,23.5%,101.4 pcf.,M.L-MH
.....
29.0 r'=-...J...~~---'
'1'.0.
Iz::~~---27.5'
27.5'-29.0'Gravel
and Boulders.
.'
Water Table Not Encountered
Thermal Probe Installed to 29.0'
12.0'-18.5'Scattered
Cobbles
Gray
SAi'JD WI'l'H SOME GRAVEL
AL'lD TRAC.t.';SILT
"O_R_GAl_-.J_I_C_MA_T_E_R_I_A_L O • 5 '
Q)PEAT
Brown
0)
@
--
27,SM
SAND ,H'l'H SOME GRAVEL
AJ.'Jl)SILT
Gray
®1'Ol,9.2%,135.S pcf.,SH
1 Ref.,Cobble,SP-SM
~,a..,I-b-~9.0'
10 44,9,9"0,129.5 pcf.1 5P-S M
SILT VHTII SOME ORGANICS
~~oH-,..-...Brown 5.S'
4.5'I--:.--JI-I.;~----=-------
Sp ;:::::
AH-G14
8';,,-~2::,;9~-~U;,;1~--v.0 '
Sp 1
Sp ,.,,..--,."...,
Sh ·_·0.-.2 89,7.0%,138.1 pcf.,SP-SM
23.0'--------
PREPARED BY:PREPARED FOR:
BORROW AREA G
AUGER HOLE AH-G14
.R&M CONSULTANTS,INC.
Scale:l"=3'
TEST PIT/TEST TRENCH LOGS
I
80+00
I100+00
o
EXPLORATORY TRENCH NO.TT"G1
D
t
DISTURBED SLOPE
j
\
47'
j
o
0 00 00Do
4Z'OISTURBEO
SLOPE
!
..<iP}i@;;F00HfT0B7c<"(.p.:;;;(V"",<nS)}.S!·'"",1
00
-20
-25
t-"'"'-30~
z
0
~-35"'...Jw
-40
-45
160 ...00 ,
150...00
I140+00
I
130 ...00
1
12.0·00
100%GRAI/EL
GRAIN SIZE ANALYSIS DATA
LABORATORY AND FIEUl ESTIMATED GRAIN SIZE DATA,FOR EACH
SOIL STRATA,HAVE BEEN PLOTTED ON THE ADJAWiJ TRIANG~LAR
DIAGRAMS.INDIVIDUAL SAMPlIS APPEAR AS SMALL T~IANGLES
AND THE DASHED LI NE AREAS ARE USED TO EST IMA TE THE RANGE
OF TEXTURES THAT MAY OCCUR HITHIN EACH STRATA.THE DIAGRAM
PROVIDES A BASIS FOR GR~PIHG THE SOILS AIID REVEALS THE
SIGNIFICANCE OF )IFFERENCES BETlIEEN GROUPS.
AS THE ENERGY OF THE FLUVIAL ENVIRON/'IENT DECRIASES <FROM
A RIVERBED TO OVERBANK DEPOSITION}THE SOILS rOLlOH A "H"
SHAPED PATTERN.INlTlATED BY A ~ECREASE IN THf COBBLE
CONTENT AND AH INCREASE IN GRAVEL.CONTINUED DECREASES I~
nlE HIERGY Of THE DEPOSITIONAL ENVIRONMENT CAmS,IHURN,
A ~ELAT I VE DECREASE I ~THE GRAVEL CONTENT,THrN lHE SAND
CONlENT AND INCREASES IN THE SlLl CONlENT.DmlNG AND
AFT(R THE DEPOSIliON OF THE SANDY AND SILTY OVERBANK
DEPOSITS,ORGANIC MATERIALS ACCUMULATE IN SURFICIAL LAYERS
OF THE MINERAL SOILS AND AS AN ORGANIC MAl.
EXPLORATORY TRENCt-
-ZO
t-
"'-25w~A
z
0
~-30
"'...Jw
-35
I
I 120+00
140-00 130+00
1l0~00
I
100...00
I90+00
I
80+00
I
70·00
I
60.00
50~00
.J
.,
L.
-5
-\0
0+00
5 10 FEET
~~iiiiiiiiiiiiiiio
I
10+00
NOTES:
1.REFEREilCE ELEVATI8NS FOR EACH TRENCH ARE ARBITRARY
AND INDEPENDENT (0,0 FT,ELEVATION IN TT -G1 DOES
NOT CORRESPOND nUHE 0,0 FT,ELEVATION IN TT-G2)'
2,THE UNIFIED SOIL CALL-OUTS ARE BASED ON THE
MINUS 3-INCH FRACTION,AND WHERE APPROPRIATE
ARE AUGMENTED BY DESCRIPTIONS (1.E.SCATTERED
&NUMEROUS)OF THE PLUS 3-INCH FRACTI ON.THE
TERM SCATTERED IS USED WHEN LESS THAN 40%OF
THE SOIL IS COMPOSED OF COBBLES OR BOULDERS,
WHI LE NUMEROUS IS USED FOR COBBLE ANT)BOULDER
CONCENTRATIONS ABOVE 40%,'-
SANDY GRAVEL AND GRAVELLY SAND WITH TRACE SILT AND
NUMEROUS COBBLES AND SCATTERED BOULDERS (SW,SP,liP,
GWL EXTREMELY COARSE GRAINED (OVER 60%COBBLES AND
BOULDERS)RIVERBED AND/OR ALLUVIAL FAN DEPOSITS OF
THE SUSITNA AND CHEECHAKO STREAM SYSTEM:SIMILAR
TO STRATA O.
5
DESCRIPTION
ORGANIC MAT (PT).BLACK TO DARK BROWN PARTIALLY
DECDrIPOSED AND UNDECOMPOSED VEGETATIVE MATTER;
COMPARABLE TO THE "0"SO IL HOR IZON.
ORGANIC SILT (OU.RUSTY BROWN SILT CONTAIlWtG THE
EXTENSIVE ROOT SYSTEM OF T:iE SURFACE BRUSH;C!Jl-
PARABLE TO THE "B"SOIL HORIZON.
SILT WITH SOME SAND AND SANDY SI LT (MU.INTER·
LAYERED (~"TO 3"LAYERS)WITH BROWN OVERBANK
(FLOODPLAIN COVER)ALLUVIAL DEPOSITS.
SAND (SP),VERY WELL SORTED,GRAY,SAND LENSES
OCCURRING WITH THE SILTS OF STRATA C•
ORGAtm SILTY SAND (Sru.SLIGHTLY ["()RE COARSE-
GRAINED EQUIVALENT OF STRATA B,CONTAItlI*i A ROOT
SYSTEM;COMPARABLE TO THE "B"SOIL HORIZON.
SAND WITH SOME SILT (SM).BROWN,SLIGHTLY i'IlRE
COARSE-GRAINEIi EQUIVALENT OF STRATA C,AND OVERBANK
FLUVIAL DEPOSIT OF THE SUSTTNA AND CHEECHAKO STREAM
SYSTHIS.
SANDY GRAVEL (GP-G\fn.BROWN TO GRAY SANDY AND
GRAVELLY FLUVIAL DEPOS ITS,PROBABLY GRADATIONAL
BETWEEN THE RIVERBED AND OVERBMK DEPOSITS OF THE
SUSITNA MD CHEECHAKO STREAM SYSTEMS.
SANDY GRAVEL WITH SCATTERED TO NUMEROOS COBBLES All!!
SCATTERED BOULDERS (GP,GW,SP,SW),VERY COARSE-
GRAINED <uP TO ABOUT 50%COBBLES AND BOULDERS)R~VER
BED AND/OR ALLUVIAL FAN DEPOSITS OF THE SUSITIiA AN!!
CHEECHAKO STREAM SYSTEI'IS,
~l ALASKA POWER AUTHORITY_J SUSITNA HYDROELECTRIC PROJECT
SCALE
-
•
-20
-15
-10
I
20+00
-25
0+00
I
30+00
I
10+00
I
40+00
5
o BOULDER
-5
...------STRATA CONTACT
&SAMPLE LOCATIONS &SAMPLE NUMBER
~GRADATIOIIAL STRATA CONTACT
I
20+00
_~CONTACT BETWEEN UNDISTURBED
,/STRATA AND DISTURBED (FAI LING)
_-'TRENCH WALL-DOES NOT CORRESPOND
TO A STRATA CHANGE.
I
50+00
1
30+00
I
60+00
I
40+00
TRENCH ND.TT-G2
I70+00
!'FOR EACH
,TRIANGULAR
'TRIANGLES
[THE RANGE
,THE DIAGRAM
[VEALS THE
iASES (FRDrI
,tOLLOW A "W·
;COBBLE
iDECREASES IN
iSES,I N-TURN,
tN THE SAND
lRING AND
lERBANK
fICIAL LAYERS
I
I
I
i
i
I
Ir-G1
I
EXPLORATORY TR.NCH
G80LOGIC-BECTION.
BORROW AR.A G
a.VIL CANYON
DATE
PREPARED •.,.
D.....TE JAN.1982
IIIEV.
1\
'"""'"
r
L
-r
LABORATORY TEST DATA
c '~<--l
PROJECT NO.
052506 R$M
November 10,1981
Client:Acres American,Inc.CON S U L TAN TS ..INC.
DATE
PROJECT NAME Sus;tna Hydroelectric PAGE NO.1 of 3SUMMARYOFLABORATORYTESTDATAPARTYNO.
RE~·IDEPTH =WET DRY MOISTUN~t9E-l t:iI P-!01 ~....-l ~2"1~"1"¥4"1/2"¥8"#4 10 20 40 80 100 200 Zp-!L.L CLASS ~ONTENr:UJ H
ril 0 '~:z:(feet)I I ~U)DENSITY DENSITY ::;,%8 ::r::.~;::to M
Irr'T'~1 2 5.0'100 67 67 63 59 56 52 48 35 20 9 6 2 2 0.9 l2.73 SP-SW
***SP-SWTTG1316.0'"72 29 29 29 27 26 23 22 1(;1 n 7 5 3 2 1 4
o 7h
TTG 1 4 25.5'100 96 86 72 54 42 12 4 4 2 6
b 7?
GW2387
TTG 1 5 37.0'100 57 57 45 40 ii ?h 7 1 ~~76 GW5654525048?L1
TTG 2 1 2.5'11 nn 99 98 92 87 84.8 t2.8?ML-MH
TTG 2 2 6.0'100 99 82 40 14 2 1 0.4 l:L 78 SP
TTG 2 3 6.5'100 97 76 60 58 52 47 38 23 9 7 2 2 1 3
I:>R7 GP
TTG 2 4 8.0'57 26 26 26 23 22 20 18 11 q S ?1 Q 0.7 R.86 SP16
TTG2 5 15.0'51 30 30 26 23 21 18 16 12 9 5 3 1 1 0.5 R.87 GP
TTG 2 8 18.0'80 57 55 51 44 38 32 27 20 16 12 7 4 3 1.2 2.79 GW I_.
TTG 2 9 24,5'81 52 52 47 41 36 31 27 21 16 12 9 4 3 1.3 2.33 GW
~HG9 4-8 3.0-10.100 96 96 94 94 93 82 f)S 48 if)1?17 1 1 ?J !:;L1 SP
~HG 9 14 45.0-46.100 67 64 58 43 39 34 29 20 11 3 3 1.7 J.53 GW-GP 135.7 130.9 3.7
lAHG.9 15 50..0-51.100 86 38 9 7 4.2 D.79 SP 105.4 98.7 6.8
ID.pr-Ie 1 'S 1.5-6.0 ~OO 99 99 98 84 75 36.1 g.63 SM
lAHG lC 4 3.0-4.5 qLl.1:\7??30 q
IAHG lC 5 4.5-6.0 103.7 89.6 15.7
lAHG Ie 6-8 6.0-9.0 !loa 95 89 85 39 29 9.1 D.64 SP-SM
REMARKS:*9"-12"
**3"9"
NOTE:SIEVE ANALYSIS:PERCENT PASSIN(
PROJECT NO.
052506
R¢M DATE November 10,1981
CLIENT:Acres American,Inc.CON S U L TA N T S,INC.
PROJECT NAMESusitna Hydroelectric PAGE NO.2 of 3SUMMARYOFLABORATORYTESTDATAPARTYNO.
DEPTH WET DRY IMOISTUR
211 ..1'"16 CLASS CONTENT
(feet')1/2 1"3/4''1/_2 fl 3/8"#4 20 40 80 100 200 L.L DENSITY DENSITY %
6.0-7.5 105.8 94.8 11.7AHG106---~-
AHGIO 7 7.5-8.5 110.8 90.2 22.9
AHG11 6,7 6.5-9.5 100 98 95 83 74 61 50 33 29 17.9 SM
AHG11 6 6.5~8.0 128.9 110.8 16.3..
AHG11 7 8.0-9.5 137.2 119.6 14.7
AHG11 9-11 15.0-31.0 100 93 89 86 79 66 55 46 40 26 22 14.1 8M------_..
AHG11 8 15.0-16.5 143.3 128.9 11.2_.
-
AHG12 5,6 93 86 82 79 66 56 45 36 21 16 2.4 SP4.0-6.0 100
AHG12 7-9 6.0-9.5 100 91 80 74 64 60 47 38 29 23 15 12 8.1 GP"";,,GM
AHG12 7 6.0-7.5 146.5 137.2 6.8
AHG12 8 7.5-8.5 153.3 143.2 7.1
AHG13 4-7 3.5-9.5 100 97 96 93 86 72 56 25 20 11.4 SW~SM
AHG13 7 8.0-9.5 121.9 97.1 25.5
AHG13 4 3.5-5.0 122.9 98.6 24.7
AHG13 5 5.0-6.5 119.9 101.6 18.0
AHG13 6 6.5-8.0 121.0 100.7 20.2
AHG13 8 15.0-16.5 100 99 97 97 93 92 75.5 ML-MH
E
REMARKS:_NOTE:SIEVE ANALYSIS =PERCENT PASSINl
];,.1 I I J ~I I I c __I J
'--~"1 '~l ')]
PROJECT NO.052506 R¢M DATE November 10,1981
CLIENT:Acres American,Inc.CONSULTANTS,INC.
Susitna Hydroelectric 3 of 3PROJECTNAMEPARTYNO.PAGE NO,SUMMARY OF LABORATORY TEST DATA
RE
T
~=WET DRY ~PI¥TU~ril DEPTH N \0U)H P-l •(feet)ri I 2"1~'1"3/4"1/2'3/8"#4 10 20 40 80 100 200 CLASS DENSITY pENSITY !'-'ON ENrilO:2:;0 I L.L P.I~::r::,::c:z %en ~M
~HG13:9 _20.0-21.~100 98 84 72 60 58 47 45 36 33 24.9 GM-SM
AHG13 10,lL 25.0-32.b 100 88 82 77 73 69 67 53 43 33 20 18 11.4 SW-SM
AHG14 8,9 6.0-9.0 100 88 88 87 84 82 78 72 61 50 35 29 14.3 SM
AHGl:4 9 7.5-9.0 148.1 135.5 9.2
AHG14 10 9.0-10.100 98 93 88 80 68 56 47 33 22 8.2 SP-8M 142.3 129.5 9.9.,
AHG14 11 15.0-16.(100 82 77 70 59 48 38 33 22 13 6.5 SP-S.M
AHG14 12 20.lr21.100 95 91 85 75 64 54 46 28 19 6.5 SP-8M 147.7 138.1 7.0.__.--'---_.
AHG14 13 25.0-26.100 98 96 94 93 91 87 85 82.9 49 16 ML-MH 125.2 101.4 23.5--f-.
'--'
r-
--
REMARKS:_NOTE:SIEVE ANALYSIS:PERCENT PASSIN
1
U.S.Standard Sieve OpenlnVlln Inches u.S,Standard Sieve Number I Hydrometer
>.
.Q
o
20
30
90
10
~
CJl
'$
40 ~
80
50 ~1Il
~oou
60 -c
~c.>
~
&l
70 Q.
QOOlloo0.0050.010.05QI
eo 100 ZOO 27040
o,~
20104
~K)50
3 2 11/2 I 3/4 1/2 3/8
100
12 9 6
500
..--
't\I \"........r--..,~,~~~IJ.-~I I I
-I-r--t--...."~
~\\\~~\\"\\~kl\,I---r-.~~---r--'\~~I\,--....,
\'\\\~~~\I\~"~~I\r---I'-I\-----"\-
\\\\\~\-.\I\~I-..~r---~~"\,"'-\"'I'-.'\"""\-
I ::--
\\\\\1\\~"\'t'---.~\~~~~~"'-."-...\"'-1\\"'\1\
\\"~\f\\~~I"r\"""
"l::~~\'~\\\i'-..
~\\'1\.1-t--..I~\\\~!":;t-~~~~I\k \\
~\i\\'"~\~\"'\,"~~\~\1\'i'---~"-.
\~~r\.~~\"1'1\\~~~"'","",1\'\\ \........
\\1'-1-~
-------
~1'\i'-....~"'~~'"fS~~r\\h ~"[\
\\"""
'\\,~f-"'-...............",~~~~~[\\\"I\.f-r----\\"","",'"~~~~~""~~-\~l\\1\"~"~r--.~"\..""~~'"I\,"~'"~~\\t---...............1"--..
~~......~~~r--r--.,,~r"'-.~~\
"""-I---,"I\,~"""""""i'-~~~~~~\~'\........~I::,.f\~""'i"-t-..
~~~......~~~~~\I'---,~~~~I I~-:::::~~~r--.~1'-1'..1\~",~~....
.......r-----~~~~""I-:>~}~\~~~'r--~~Io-~"i::---~l'i;;to.,........r-:--..::::::~".\--~~~
r---r--.:-..:-
°'000
80
90
100
30
20
10
70
~40u
~
~
Q..
-.c:.
at
'i
~60,..
.Q
....~50
G:
BOULDERS I COBBLES GRAVEL
Coarse I Fine Medium
SAND
Fine
FINES
Silt Sizes
SAMPLE NO.I CONTENT
y
DENSITY LL PI CLASSIFICATION 8 DESCRIPTION
BORROW AREA G
COMPOSITE GRADATION CURVE
DRAWN BY:
APPROVED BY:
DATE:
PROJECT NO.
C~~"~)")'}
US.Standard Sieve Openings in inches U.S.Standard Sieve Numbers Hydrometer
50
20
10
o
-J;:.
01
'4)
40 ~
>...c
80
30
90
l..
Q)
~oou
60 -c
Q)
~
Q)
70 a...
0.001 1000.0050.010.05QI0.!5510!50100!500
----"--.~~------
I I '\I II I I I II II I I I I
I
\
\
)\
i\
,1\
~+-~
"'"~
,
~rG..
~~
'~
I 'r-...--
'""-,-
I
"'"--'")""I
~--c------
lei-I--'"'-f-.Q r---.I--.c..-"'.I,...I01000
10
20
70
90
30
100
80
>-
.Q
-&.
Ot
"i)
~60
-c~40
~
II)
Q.
.....
~50
u::
BOu..OERS COBBLES I GRAVEL I SAND I FINES ~
Coarse I Fine I Coarse I Medium I Fine Silt Sizes ~SiZeS
SAM P LE NO.I CONTENT
TT-G1 #2
y
DENSITY LL PI
APPROVED BY:
PROJECT NO.052506
DATE:Dec.1981
BORROW AREA G
TEST TRENCH TT-61
II..------..I DRAWN BY:J MIIIII• •
I
U.S.Standard Sieve Openings in Inches U.S.Standard Si.v.Numb.r.Hydrom.t.r
o
10
30
20
....c
Cl
'i)
40 ~
>.
~
90
80
~
50 Q)III...oou
60 ...c::
QJ
(.):u
70 Q..
0.00,'000.0050.010.05QIO.~~K)~100~oo
I 9 6 :3 2 11/2 I 3/4 1/2 3/8 4 10 20 40 80 100 200 270
I I I I I I I I'II I I I I I
I
1\
\
I \
\
~
\
\
.\
\-\
\
I
1\
1\
I
~-~f0.
)~Gl
r--..........Ie...
..............~14----fe--....~r---~
10
°1000
>.
~
~50u:
30
20
70-.r:.
at.;
~60
80
90
100
-C
t)40
~
Q)
11.
BOLLDERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
SAM PLE NO.I CONTENT
y
DENSITY LL PI CLASS CLASSIFICATION a DESCRIPTION
TT-Gl #3 sp-sw GRAVELLY SAND WITH TRACE SILT AND NUHEROUS __-.COBBLES I
I I I I I I I ----t
DATE:Dec.1981
~OJECT NO.052506
APPROVED BY:BORROW AREA G
TEST TRENCH TT-G1
II,I I I I -------.-i DRAWN BY:J .11.I
J J J J
US.Standard SI .....Openings in Inches u.S.Standard Sieve Numb.r s Hydrom.t.r
o
30
20
10
50
90
-s::.
01
-ij
40 ~
>.
A
80
~
t)
~
~oo
l>
60 4-
C
Q)
~
Q)
70 a..
Qoo,IOO0.0050.010.05QI0.55()50100500
12 9 6 3 ,11/2 I 3/4 1/23/8 4 10 20 40 80 100 200 270
I I I ",II I I I I II I I I I I
Ira
\
_.f\
\
\
~
\
\
\
I
,
\
~
\
\
I r\
1\
I ~I~
~h II---b.-ovr---f--r.\._
IV1
10
°1000
20
30
80
100
70
90
~50u:
>.
~
-~40o
~
t)
Q.
-..
01
'i
~60
BOll.DERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
SAMPLE NO.Y
CONTENT I DENSITY LL PI CLASS CLASSIFICATION a DESCRIPTION
TT-Gl #4
1 I I I I GW GRAV.8L WITH SOME SAND
BORROW AREA G
TEST TRENCH TT-Gl
DRAWN BY:J .M.
APPROVED BY:T.I.
DATE:Dec 19d1
PROJECT NO.05LS06
~~
\
us.Standard Sieve Openings in Inches u.S,Standard Sieve Number s Hydrometer
o
10
30
20
-~
01
'ij
40 ~
>.
~
90
80
~
50 Il~
~oou
60 -c:
Q.l
~
Il
70 a..
QoollOO0,0050,010,00QI0.0eK)00100eoo
20
30
70
80
10
90
0 1000
100
-~
01
'ij
~60
>.
~
-c~40
~
t)
Q.
:u 50cu::
BOLLDERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
SAMPLE NO.Y
CONTENT I DENSITY LL PI CLASS CLASSIFICATION a DESCRIPTION
TT-Gl #5 GW SAND WITH SOME GRA~L AND;,.NUMEROUS COBBLES I
BORR01.v AREA G
r:J1EST TRENCH TT-G-l
DRAyvN BY:J .M.
APPROVED BY:T.I.
DATE:Dec.1981
PROJECT NO.052506
~I j J "ccL~1 ,I )
~'~""~'l -)'1
U.S.Standard Sieve Openings in Inches U.S.Standard Sieve Number s Hydrometer
...
C1l
III
L-oo
U
o
30
10
c
C1l
U
'-Q)
70 0..
90
50
-r:.
0'
'i
40 ~
>....c
20
80
60
0.001 100
0.0050.010.05QIo.~~K)50100~oo
12 9 6 3 2 11/2 I 3/4 1/2 3/8 4 10 20 40 80 100 200 270
I I I I I II I I I II I l..l ~I I I
..........--....""'t
~-
l
--
--
)j--
--------
_..
10
°'000
~50
u:
70
90
30
100
80
20
~
0-.;
~60
-c:~40
~
I)
a..
>....c
BOu..OERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
SAMPLE NO.y
CONTENT I DENSITY LL PI CLASS CLASSIFICATION B DESCRIPTION
TT-G2 #1 ML-MH SIL'r ~vrl'H SOME SAND AND CLAY
BORROW AREA G
TEST TRENCH TT-G2
DRAWN BY:J.M.
APPROVED BY:T.I.
DATE:Dec.1981
PROJECT NO.
US.Standard 51elle Openings in Inches U.S.Standard Sielle Numbers Hydrometer
~v
~oo
U
50
o
20
30 -.c
011
'Qi
40 ~
>.
..Q
10
90
...c::
(l)
~
Cll70a...
80
60
0.001 1000.0050.010.05Ot0.!S5K)!So100!SOO
12 9 6 3 2 11/2 I 3/4 1/2 '8 4 10 20 40 80 100 200 270
I I I I II I I I '!'r-I--f\I I I I I
~
~
I
'\
1\
I \
\
I \
\
\\
~'\
\
I \
)\
\
~r--.....
~
''0...-.:..(
10
°1000
20
70
90
80
100
30
-s::.o
CD
~60
>.
..Q
Qj 50c:u::-c::~40...
CDa..
BOLLDERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
SAMPLE NO.Y
CONTENT I DENSITY LL PI CLASS CLASSIFICATION a DESCRIPTION
TT-G2 #2 SP SAND
BORROW AREA G
TEST TRENCH TT-G2
DRAWN BY:J .M.
APPROVED BY:T.I.
DATE:Dec.1981
PROJECT NO.052506
_J ,J -)_J
1
us.Standard 511\11 Openings in Inches U.S.Standard Silve Number s Hydromat.r
....
CD
~oou
20
o
10
30
50
c
Q)
~
C1l
70 n..
-.z::.
OIl
'i)
40 ~
>.
.Q
80
90
60
0001'000.0050.010.05010.55()50100500
,...-,...----Ie;~a iJ e.II/e.I ,,/~I/e."/0 At IV e.V ..v ov IV\)e.vv c.rv
I I "'r--...~II I I I II II I I I I
I
1\
\
\I
~
\
\
\
..........~
I ~"a
'r--,.
II"
I "'-
""~",
"'""-
0~--k I--.---f..a.J.:L
10
0'000
;50cu:
30
90
20
70
80
-&;
01
CD
~60
100
-~40o
"-
CD
Q.
>.
.Q
BOLl.DERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
SAM PLE NO.I CONTENT I DENSITY LL PI CLASS CLASSIFICATION 8 DESCRIPTION
TT-G2 #3 GP SANDY GRAVEL
DATE:Dec.1981
i DRAWN BY:J .M.
APPROVED BY:T.I.BORROW AREA G
TEST TRENCH TT-G2
,,,_•••",~••~~.~...",".~.!=I PROJECT NO.052506 I
u.s.Standard Sieve Openings in Inches u.S.Standard Sieve Number I Hydrometer
50
80
20
10
90
30 -.c
QII
'Qj
40 ~
>..c
o
....
II)
~cou
60 -c
Q)
~
II)
70 a..
QOOIIOO0.0050.010.05Q/0.55K)50100500
U 9 6 3 2 11/2 I 3/4 1/2 3/8 4 10 20 40 80 100 200 270,I I I II I I I II I I I I I I
I \
\.-
)\
\1--1---
\
--
\
~
\
\
I \
1\
I 1\
Ia '"I,:,
i"G-fe--.L\)
9 ~t-----t-=Jt-r-r--fQ....
~r-----FaJ«I l"-t--I-c.:I
r--re--e I i
I
10
0 1000
20
90
70
80
30
100
>..c
~50cu:-c:~40
~
II)a..
-s;;o'.~60
BOLLDERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
CLASSIFICATION a DESCRIPTION-..-...--..-...-.-----.--.....----------.ISAMPLENO.I 'CONTENT'"I DENsiTY I LL I PI I CLASS
T'P-G2 #4 I I I I I SP I G_~~~.LY.SANP'..~~~~_~~CE SILT AND.NUMEROUS 'C012BLES I
I I I I I I I I
------...__._.-.---_.•----------
BORROW AREA G
TEST TRENCH TT-G2
,
DRAWN BY:J .M.
APPROVED BY:T.I.
DATE:Dec.1981
PROJECT NO.052506
J
'~""'-<1 '-""-~l
•~.__tr~""W •
u.s.Standard Sieve Openings in In ches u.S.Standard Sieve Number.Hydromitter
50
.....
J::
01
'ij
40 ~
>.
.Q
20
30
10
o
90
80
~
Q)
~oo
(,)
60 .....c
Q)
~
Q)
70 Q..
QOO/IOO0.0050.010,05UI0.551050100500
I 9 6 :3 2 11/2 I 3/4 1/2 3/8 4 10 20 40 80 100 200 270
"I I I II I I I II I I I I I I
1\
--
I \
I \,---
\
\
-------",-
I \
..-,-
I \
\
I ~
\
I
\f-----'-
1\
I
r\,-
"'El.
---I---
)~Q.-----~~I f
...............
Ii>----e ----b
-I--.I-.Gi
----
-\iI--E)
--0'000
10
-~
01
'i)
~60
20
90
70
80
30
100
Qi 50c:u:
>.
.Q
-~40o
~
II)
Il..
BOLLDERS COBBLES GRAVEL SAND ~----FINES =--==--..----~
Coarse Fine Medium Fine I Silt Sizes !Clay Sizes
PILLY
DENSITYSAMPLENO.I CONTENT CLASS CLf-.SSi~~'2~TION B DESCRIPTION
I TT-_~_2_iLJ I I I [GP QANDY---GRAVEL WITH TRACE SILT AND-;jUMEROUS COBBLES -------I
APPROVED BY:T.I •
DATE:Dec.1981
PROJECT NO.052506
DRAWN BY:J .M.
BORRO~'J AREA G
TEST TRENCH TT-G2
I I I !I !I .._.. .__,.._
I
I I I I I -4==-.---r~~===·~~·--=-=-==--===-~-=----=-------_.._------I
U,S,Standard Sieve OpeninQs in Inches u,S,Standard Sieve Number s Hydrometer
t...
Q)
~oo
U
>..a
20
o
30
10
-c:
Q.l
~
Q)
70 0_
.c
01
'ii)
40 ~
50
90
80
60
0.001 1000.0050.010.050.10.55K>50100500
I 9 6 3 2 11/2 I 3/4 1/2 3/8 4 10 20 40 80 100 200 270
"I\.r
r I 'I I I I I II I I I I I
\
\I
I \
\
\
\j\
\
Q.......--""lil -----"I\."---------
I "
--I
f---------r-----------
I ~-.1-----t----'\~
.......,-----r----
)!-----,
~.........---~r--I --..........
"""G !'------~
_.~.1-1-0 --..ll-.,-'-----"_'--.___~__----_._
10
°1000
20
30
70
80
.s=o
'Q)
~60
100
90
,.,
.Q
i 50cu:-c:~40
t...
Q)a..
BOLLDERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
SAM PLE NO,I cONTENT'"I DENSrn I LL I PI I CLASS CLASSI F ICATION a DESCRIPTION
I ·TT-G2 #8 I ~I I I GW..I SANDY GRAVE'L h"ITHNUMEROUS COBBLES ._._
I I I I I I
----_.._---------------
I I I I I I --
BORROW AREA G
TEST TRENCH TT-G2
DRAWN BY'J .M.
APPROVED BY ;-rr-.-r-.---1
DATE:Dec.1981 1
PROJECT NO,052~Ob--'
J .J }
/"'~'l --~-J ~--'--'1 "--'1 '~-'-''']_._-,
J
U.S.Standard Sieve Number su.s.Standard Sieve Openinos in Inches Hydrometer
4 10 20 40 80 100 200 270100II'I ~IIIII r III I II I III1II I I I I 1111"'--'I I --,0
9011111114 11111111 11111111 I 11111111 I 11111111 1111111 I-+--10
80 111111 I:I 111111 I I IIIII1 i +----20
i:E __1m I :i
:>.
.Q~50tHmtE I ~H50 ~10-
111
~oo
_""I U~40"60 e
::Q..Q.l
Q)•-(.J
Q ~~30 \-.70 Q..
~
................!G....
20._--~----I80
~P---.....I +--_......-
10 -Gl.-......---l90..,.___..I
o " "!I I I I !li..LL I I I I " " I I I -'-----L "I 11 1 r--~r:----f-Ie L J--~-~-j 100
1000 500 10050 kJ 5 I o.~01 0.05 0.01 0005 QOOI
BOLLDERS COBBLES f GRAVEL I SAND ±-----~--iiJ
Coarse I Fine Coarse I Medium !Fine Silt Si;es ..ICloy Sizes
CLASSIFICATION 8 DESCRIPTION
SANDY GRAVEL WITH NUMEROUS COBBLES
SAMPLE NO.~g~~~~~E Df~siTY I LL I PI ICLASS
[j_T~2·..#9 I I GW i ------------
I I I I I I .--.-------...-~.--------_.._--
I I I 'i I .-.----.---._--------.----..---------.-----..-
~-----i;;;;~~;;;;lm::--c--~~~--~~--------i-~-~~=----~
TEST TRENCH TT-G2 I DATE:-5ec.-1981------
I PROJEC7"r-N'O.-65E"'TJ6------...__....;,;,,;,,;,;,,.,,'_~_.~'"~..OC'...."
U.S.Standard Sieve Openings in Inches U,S.Standard Sieve Number s Hydrometer
>.
..Q
o
10
20
30
50
~
Q)
III
L-oo
l>
60 +-c::
Q)
~
Q)
70 a...
.-.c.
CJl
'il
40 ~
90
80
0.00,1000.0050.010.05
200 270
OJ
80 10040
0.5
20104
5K>50
:3 2 11/2 I 3/4 1/2 3/8
100
12 9 6
500
20
80
30
10
90
0/000
70
100
~50
u::
-.r::.
Ol
l»
~60
>.
.Q
.-c:~40
~
l»
Q..
COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
TRACE SILT
SAMPLE NO.CLASS CLASSIFICATION a DESCRIPTION .
AH-G9 #4-8 -'S"P-:sMl SAND WITH SOME GRAVEL ---I
BORROvJ AREA G
AUGER HOLE AH-G9
DRAWN BY:J .M.
APPROVED BY;T.I.
DATE;Dec.1981
PROJECT NO.052506
J I ,_._J .1 J J
u.s.Standard Sllve Openinos in Inches U.S.Standard Sieve Numbers Hydrometer
0
10
20
30 .......c
01
'Q)
40 ~
>.
.Q
....
-----i50 Ql
~
0
0u
60 ......
C
Ql
~
(l.)
~70 n...
80
90
O~OIIOO
-TC~Y-~i?~~1
0.005
FINES
0.01
Silt Sizes
0.05
I
I
QI
~I
I Fine
SAND
0.5
Medium
IJCoarseIFine
GRAVEL
50 ~5
r Coarse
I
100
COBBLES
500
BOll.DERS
I t-o..._
20 1 "I'-"-----tti I 111-1 11 1 I I+-+-I-I
~~-------W~I II I I I I I I-+-..........10 I ~
0 1000
12 9 6 3,11/2 13/4 1/23/8 4 10 20 40 80100 200 27010011IIIrI'I II I 111 1 11 II1I I'11'1111 II 1-[--,-IIIII r I II I II I 1I11I1 I I rIll ii'I i I
30 "II I I I I ~+++I I I II I I I I I
70 I I I I I I I I I I I I I I -1~I~01~60 "'1'\I I I I I I I I I 1+++I I I I I I I I I I I I I -
~\~50 \I11I1 I 11II 1111I I I I I II1II1 I I-t---
~40 _~I IIIII1 I I I --++++++-+--1 1 ~
Qla.
80 II I I I I I'I II I I I I I I I
H-I-+-+-+~---+--+---++-+-++-t-t--J-I---+----++++-t-I I I I I I I I I I I I I I I I I -f-I I I I I I I I I I I
SAMPLE NO.MUIS rURE
CONTENT
DRY
DENSITY LL PI CLASS CLASSIFICATION B DESCRIPTION
AH-G9 #14 3.7 130.8 GW-GP SANDY GRAVEL
I I I I I
BORROW AREA G
AUGER HOLE AH-G9
DRAWN BY:J .M.
APPROVED BY:T.I.
DATE:Dec.1981
I--I
PRO,JECT NO.052506
U.S.Standard Sieve Openinos in Inches U.S.Standard Sieve Number s Hydrometer
>.
.Q
L..
Q)
~oo
U
o
30
10
50
20
-.c:.
0'
'il
40 :t
.-c
Q)
2
Q)
70 (L
80
90
60
0.00,1000.0050.010.05010.5!51050100500
12 9 6 3 2 11/2 I 3/4 1/2 3/8 4 II'20 40 80 100 200 270
I I
I I I
I I I II '"I I I I I
'""t\~
\
\
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\
I \
I \---I
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1\
f----.._-I--f-.
I \
\
)\
\
\
'G--~
'"G)
10
0 1000
20
30
100
80
-.&=
01
Q)
~60
90
70
>.
.Q
Q:j 50c::u:
~40o...
Q)
a.
BOll..DERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
SAND WITH TRACE SILT6.8 I 98.7
CONTENT CLASSIFICATION a DESCRIPTION-----------------------11
SAMPLE NO.
AH-G9 #15
BORROW AREA G
AUGER HOLE AH-G9
DRAWN BY:
APPROVED BY:
DATE:Der~
PROJECT NO.
~.._~-J j )••J J 'I
'~~l "'.~"'.~~]-----~l )]
U.S.Standard Sieve Openings in Inches U.S.Standard Sieve Number I Hydrometer
lo.
/I)
~co
U
o
10
20
90
30
50
...c:
Q)
~
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70 a..
80
-.c.
01
'$
40 ~
>.
..Q
60
0001
100
0.0050.010.05
200 270
01
80 10040
O.~
2010!l
~()50
3 2 11/2 I 3/4 1/2 3/8
100
12 9 6
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I I I I I I
I I II rl ,-'"'I'\.
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~-0 1000
30
70
80
90
20
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01
'CD
~60
100
10
-c:
II)40
~
II)a..
>-
.0
~50c:
LL
BOll..DERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine Silt Sizes [Clay
SAMPLE NO.Y
CONTENT I DENSITY LL PI CLASS CLASSIFICATION a DESCRIPTION
AH-G10 #3-5 SM SILTY SAND
I I I I I I --i
BORROW AREA G
AUGER HOLE AH-G10
DRAWN BY:J .M.
APPROVED BY:T.I .
DATE:Dec.1981
PROJECT NO.052506
u.S.St andord Sieve Openings in In ches U.S.Standard Sieve Numbers Hydrometer
~
Q)
lit....oo
U
o
30
10
-.c
at
'Q)
40 ~
>.
.Q
50
90
20
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Q)
~
Q)
70 Q..
80
60
12 9 6 3 2 11/2 I 314 1/2 3/8 !10 20 40 80 100 200 270
I I I I II I I I II ~---I I I I Ir--....
~
1ilr--,
'"'-
'\
\
\
\
\
\
I I\
\
\
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1\
1\
I
ti)10
100
-.c.
01
Q)
~60
30
70
80
20
90
>.
.Q...~50u:-c:~40...
Q)a..
0.01°1000 500 100 50 D 5 O.~QI 0.05 0.005 0001 100
BOLLDERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
SAMPLE NO.
AH-G10 #6-8
Y
CONTENT I DENSITY LL PI
SAND WI
CLASSIFICATION 8 DESCRIPTION
BORROvJ AREA G
AUGER HOLE AH-G10
DRAWN BY:J .M.
APPROVED BY;T.I.
DATE:Dec.1981
PROJECT NO.052506
j J .J _J .J
~"o_>1 --"OO·~-·l -1 --1 1
U.S.Standard Sieve Openinos in Inches u.S.Standard Sieve Numbers Hydrometer
l...
(I,)
~oo
U
50
90
30
o
20
10
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at
Qi
40 :s:
>.
.Q
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~
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70 a...
80
60
0.001 100
0.0050.010.05010.551050100500
~I T'jf-i -I T ---,'.-
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I T I I I Po.::1 ,_.,-1 -<--.-.-FFUI'-'r -'-~-
l I ~c--+--~LI -I ,ffm=I~-I I e--~T
J II I -I Ft=t ~l '-i-11 I -->---e--'r-I T-I Ti ~'--"-'-I 1-
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I \~.J +--
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L
I 1 '\HEE---_of ~lr1-r-~
LIT-1 ~I III r'~---lrttt tf I ---.J-'J LJ .I I-~----f-----~,1,1if I T mi -ti-f ~~H 1-if-T T ~-1 I I I I J ~.,1 i-LL I I r I TIll I 1,1 tE 1ti T I .-~---__L_.JW --+---
L J I__rI__-J
0'000
10
70
90
20
80
30
100
-.&:.
01
l»
~60
-~40::
l»a..
:>..
.Q
Q.;50cu:
BOLLDERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
SAMPLE NO.
AH-Gll #6,7
Y
DENSITY LL PI
SM
CLASSIFICATION a DESCRIPTION
SAND WITH SO!lli SILT AND GRAVEL
BORROW AREA G
AUGER HOLE AH-Gll
DRAWN BY:J.M.
APPROVED BY:T.I I
DATE:Dec.1981
PROJECT NO,052506
US.Standard Sle ....e Openinos in Inches U.S.Standard Sieve Numbers Hydrometer
>..c
o
30
10
20
-.c
01
'il
40 ~
50
90
80
L-
a>
~oou
60 --c
a>
~
Q)
70 Q...
0.00,1000.0050.0\0.05Qf0.55o50100500
'e.<7 'D ..J e.I '1..'I ..J/"I/~oJ/O -r IV e.v -rv av IVV 'vv "V
I I I ""I I I II II I I I I I,
~
I \
~
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I "'"~
I ~
"'".....$
r"--r-.....,r-.......I -
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l ~-.
.....................I
'@
II
--~---
10
0 1000
20
-s::.
01
Q)
~60
100
70
80
>.
~
90
30
Qj 50c
iL-~40u
~
Q)
a.
BOLLDERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
SAMPLE NO.CLASSIFICATION a DESCRIPTION
AH-G11 #8-11 GRAVELLY SAND WITH SOME SILT _
BORROW AREA G
AUGER HOLE AH-G11
DRAWN BY:J .M.
APPROVED BY:T.I.
DATE:Dec.1981
PROJECT NO ()52506
J J .]I
""'~"'1 r-'~1 ~--'-1 '''''-~'~-',""'-'1 \r~1 1 1
us.Standard Sievi Openings In Inches U.S.Standard Sllvl Numbers Hydrometer
o
90
30
20
-.c:
01
'i
40 ~
10
80
>.
~
~50 (l)~oou
60 ......c
Q)
~
CI.l
70 Q..
QOO,loo0.0050.010.0!5QI0.!5!5K>!50100!500
"
~'0 ~,IlL'I ~/"II'~/O ..IV 'V "'tV OV IVV ,vv ,rv
I I I I ~I ,I I',I I I I I
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1'0...
~
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~
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""~
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I "-~
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\
'0
0 1000
10
70
90
80
20
100
-~40u-..,
Q.30
>..c
•50cu:
-.c.o••~60
BOLLDERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
SAM PLE NO.I CONTENT
AH-G12 #5,6
y
DENSITY LL PI
GRAVELLY SAND
CLASSIFICATION 8 DESCRIPTION
I ""f I I
BORROW AREA G
AUGER HOLE AH-G12
DRAWN BY:J .M.
APPROVED BY:T.I.
DATE:Dec.1981
PROJECT NO.052506
u.s.Standard Sieve Openings in Inches U.S.Standard Sieve Number.Hydrometer
50
-.c
ClIl
'Q)
40 ~
>.
.Q
10
20
o
30
80
90
L..
Q)
~oou
60 -c::
111
(,):u
70 CL
12 9 6 3 ,11/2 I 3/4 1/2 3/8 4 10 20 40 80 100 200 270
I I I 1 \'I I I I II I I I I I
I
\~
\
I I\.
"\
'\.,
"
I
r'\,
~
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I ~
I"l ......
........~
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~
r-..~10
90
100
70
30
80
20
-~
C'l
l»
~60
L..
~50
u:
>.
.Q
-c:~40...
l»a.
0.01°1000 ~OO 100 50 o 5 O.~QI 0.05 0.005 QOOllOO
BOll.DERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
SAMPLE NO.y
CONTENT I DENSITY LL PI CLASS CLASSIFICATION a DESCRIPTION
AH-G12 #7-9 GP-GM!SANDY GRAVEL WITH TRACE SILT
BORROW AREA G
AUGER HOLE AH-G12
DRAWN BY:J .M.
APPROVED BY:'r.I.
DATE;Dec.1981
PROJECT NO.0<;2506
".J 'J .1 ~~J J ,,'J
-]~I "-n~·-··l ,-····~·1 ·1
u.s.Standard 51.11.Openings in Inches u.S.Standard Sle\/e Number s Hydrometer
>.
..Q
L-
CD
~ooo
o
10
4-
C
CD
~
CI.l
70 CL
30
20
50
90
4-.c
01
ii
40 ~
80
60
0.001'000.0050.010.05QI0.0oK)~O100~oo
~~...II'"...........-,--,-,~-~~~--._----...'-I I I I II II~~I I I I J I-~--
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\
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I '"--
''0
I
~--L--0 1000
10
30
:u 50cu:
100
70
80
20
s:::.
01
CD
~60
90
>..c
-~40
u
~
CDa..
BOl1..0ERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
SAMPLE NO.CLASSIFICATION B DESCRIPTION
AH-GIJ #4-7 SAND WITH TRACE SILT AND GRAVEL I
I I I I I I I I
BORROW AREA G
AUGER HOLE AH-G13
DRAWN BY:J .M.
APPROVED BY;T _I
DATE;Dec.1981
PROJECT NO.052506
u.s.Standard Sllve Openings in Inches U.S.Standard Sieve Numbers Hydrometer
>-.c
o
10
30
20
90
-4-
CIt
"Qi
40 ~
80
"-50 Q)~oou
60 -C
Q.l
~
Q)
70 a..
0001 1000.0050.010.05010.!5~K)50100~oo
12 9 6 3 2 11/2 I 3/4 1/2 3/8 i 10 20 40 80 100 200 270
I I I I II I I I I 11 A I I I
rv r-.--~l
\
\
I 1\
\.I'
I
I
)
--
--
10
°1000
20
30
80
100
70
90
>-
.Q
-.r.
01
'ij
~60
-~40u
"-
lD
Q.
;50c:
LA:
8Ou..DERS COBBLES GRAVEL SAND FINES ~
Coarse Fine Medium Fine Silt Sizes ~Clay sjZeS
SAMPLE NO.Y
CONTENT I DENSITY LL PI CLASS CLASSIFICATION 8 DESCRIPTION
AH-G13 #8 ML-:-MH I SII,T WITH SOME SAND,SOME TO TRACE CLAY
APPROVED BY:T.I.
DRAWN BY:eJ _M_
BORROW AREA G
AUGER HOLE AH-G13 DATE:Dec.1981
,.._~••_~_.~,I I PROJECT NO.052506
..J ,..J I ..~I J
"'~"l 1
US.Standard Sievi Openlngl in Inches u.S.Standard Sllvl Number I Hydromlter
L-
Q)
lit
L..oou
o
10
20
30
50
90
-.c
01
Qi
40 ~
:>.
.Q
-c:
Q)o....
CIl70Q..
80
60
0001 1000.0050.010.05010.55k:)50100500
L If 11 ,-~'.
I
I II II -.I ~1\I "T·--I-~_1 "I 1"1[1 --f.-\>-+-<-'-<-1 I -,-.,-T ---_.-
.l I "-0=I 1 n \~I +-+--I----mtt~1
T ~-~--l =:~-l~P Il 1 '\~~e-'--1 ,~~'-'--T L~~I T -C:=:J
c 1 I I I I 1 fTl -'"J -I I 1 ~-l----JL "1 ~----.J
'-'-1 I -L ==f 1 ~-~I I·1 L-Jl 1Tf---l----.11-c---f.-~1 rr T I[1 I i(I .--+--r I I 1 _1
II i U 1,r-6 ~-1 I J:1~~'--H-"---
U I I II I I 1 1 1 -f.-
1 "I I I 1 n ~-lim-1 '"1 U --I I·1 I 1-l:~~I lIT-I 1 h:h-±P=~~'-I~~~RIR=FR't ~I+H ~t 1 1 ~~'"1T Till
I I ~I 1 _J I ~I ',1 I I J 1::::1_1 '
J I IT;I ---+---ftt'-~~~1 1 F "'~M-~I 1~1
U I I I 1 111,1 r++-+---1LiL4-~1f J '--I I ~--
Will --r-r-II dHi:b II 1tt-H-'-fR 11 =t=ffi=F:-=.~-=m I I III LLI I I -e-Ii I I I I I
20
10
30
80
90
°1000
70
100
-.co
'i
~60
>.
.&:II
o 50cu:
~40o...
Ga..
BOU-DERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
SAM PLE NO.I CONTENT
AH-G13 #9
y
DENSITY LL PI CLASS
GM-SM
BORROW AREA G
AUGER HOLE AH-G13
DRAWN BY;J .M.
APPROVED BY:T.I.
DATE:Dec.1981
PROJECT NO.
US.Standard Sieve Openings in Inches U.S.Standard Sieve Numbers Hydrometer
o
>.
~
10
20
30
50
-.c
01
'ij
40 :t
90
80
....
Q)
~oou
60 .....c
CIl
~
Q)
70 a...
12 9 6 3 ,11/2 I 3/4 1/2 3/8 4 10 20 40 80 100 200 270
I I I I '1\II I I I II II I I I I I
\-~"I ~
'\~
~
l,j t-t-r--~
""-
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I "-",
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r-......."(i)
10
30
70
20
-.&:.
01
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~60
100
90
80
-c:~40
~
Q)
Q..
>.
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Gi 50c:
iL:
0.01°'000 500 100 50 k)5 0.5 QI 0.05 0.005 aool'OO
BOLLDERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
SAMPLE NO.I CONTENT
y
DENSITY LL PI CLASS CLASSI F ICATION a DESCRIPTION
AH-G13 #10.12 SW-SM GRAVELLY SAND WITHTAACE SILT
APPROVED BY;T.I.
DATE:Dec.1981
PROJECT NO.052506
DRAWN BY:J .M.
BORROW AREA G
AUGER HOLE AH-G13
I I'I I ,I .--.---.------.....-.-.I I
J .,c]],',.J J ..]
~.~~··l '~~"~l "~''"'l '))
u.s.Standard Sllvl Openings In Inches u.S,Standard Sllvl Numbl'I Hydrometer
50
20
10
30 -J::
01
'j)
40 ~
>.
.Q
o
80
90
l-
(I)
~oou
60 -c
(I)
~
Q)
70 ll.
0.00,1000.0050,010.050.10,55K:>50100500
12 9 6 :3 i::11/2 1 3/4 1/2 3/8 4 10 20 40 80 100 200 270 .-
I I I I I I I II I 1 I I I
\
\
a-i-a.__.-
-Q....
~~
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~
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I "",,---"'I
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l \--
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10
0 1000
I-~50
u:
20
90
70
80
30
100
>.
.Q
-.c.
01
'Ii
~60
-~40
o
l-
ll)a.
BOLl..DERS COBBLES Coorse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
SAM PLE NO.,CONTENT
AH-G14 #8,9
y
DENSITY LL PI CLASS
8M
I I I I I I I ......
BORROW AREA G
AUGER HOLE AH-G14
DRAWN BY:J.M.
APPROVED BY:T.I •
DATE:Dec.1981
PROJECT NO.052506
us.Standard Sle\le Openings in Inches U.S.Standard Sieve Number I Hydrometer
o
30
10
50
90
20
80
.....r::.
01
'ij
40 ~
>.
..Q...
lLl
~oou
60 ....c:
lLl
U
W
70 0..
----,..,-,-.--.---._---...---
I I I ,
,,-'-I I
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'l;
r-..
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I"~
~
I \
1\
~\
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'Q)10
100
70
20
80
90
30
-.r::.
01
CD
~60
>-
..Q
Q;50c
iL-c::~40
"-
CDa..
0.010100050010050K)5 0.5 QI 0.05 0.005 QOO,IOO
BOLLDERS COBBLES Coarse
GRAVEL
Fine Medium
SAND
Fine
FINES
Silt Sizes
SAMPLE NO.CLASSIFICATION 8 DESCRIPTION I
AH-G14 #10 SAND WITH SOME GRAVEL AND TRACE SILT
BORROW AREA G
AUGER HOLE AH-G14
DRAWN BY:J .M.
APPROVED BY:T.I.
DATE:Dec.1981
PROJECT NO.05250
c~-~~-l ~-J
US.Standard Sieve OpenlnQII in Inches U.S 0 Standard Sieve Number II Hydrometer
o
30
10
90
-r::.
OIl
'Qi
40 ~
>.
..Q
20
80
...
50 Q)~
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60 -c
Q)
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70 0.,
0001'000.0050.010.05QfO.~~K)!50100~oo
-c _
I I
-
I I I I
-;
c.
I'I
ceo ,I ,'I II \'I I'I
-
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DATE:Dec.1981
PROJECT NO.
APPENDIX H
SEISMIC REFRACTION SURVEY-1980
FINAL REPORT
SUSITNA HYDROELECTRIC PROJECT
SEISMIC REFRACTION SURVEY
SUMMER,1980
Submitted To
R &M Consultants
5024 Cordova
Anchorage,Alaska 99502
19 December 1980
project No.4l306I
R & M Consultants
5024 Cordova
Anchorage,Alaska 99502
Attention:Mr.Gary Smith
Gentlemen:
SUBJECT:FINAL REPORT -SUSITNA HYDROELECTRIC PROJECT
SEISMIC REFRACTION SURVEY,SUMMER,1980
Enclosed are 10 copies of our Final Report from the geo-
physical survey conducted under our agreement of July 23,
1980.This report reflects your comments and those of
Acres American to our draft report dated October 23,
1980.
As requested by Mr.Robert Henschel of Acres American
in our meeting earlier this month,we are preparing a set
of recommended additional surveys to investigate areas
where uncertainties still exist.These recommendations
will be forwarded under separate cover.Mr.Henschel also
requested revision of the profile figures in this report to
reflect true elevations rather than relati ve elevations.
We will make the appropriate changes and forward revised
drafts when datum elevations become available.
We have enjoyed working with you on this project.
call us if you have any questions or comments.
r Very truly yours,
~e~
Deputy Director of Geophysics
JDR:DEJ/ab
Enclosures
Please
~c~
Dennl.s E.Jensen
Project Geophysicist
-
TABLE OF CONTENTS
LETTER OF TRANSMITTAL
TABLE OF CONTENTS,..
1.0 INTRODUCTION ••......1-1
~1.1 Purpose ••................1-1
1.2 Scope of Work ••1-2
2.0 DATA ACQUISITION ••••.....2-1
3.0 DATA REDUCTION PROCEDURES ••3-1
4.0 DISCUSSION OF RESULTS.4-1
4.1 Traverse 80-1.4-1
4.2 Traverse 80-2 ••4-3
4.3 Traverse 80-3........4-5
4.4 Traverse 80-6......4-6
4.5 Traverse 80-7 ••4-8
4.6 Traverse 80-8 ••............4-9
4.7 Traverse 80-9 ••......4-10
4.8 Traverse 80-11 •.4-10
4.9 Traverses 80-12, 80-13,
and 80-15 .•••........................4-11
5.0 GENERAL OBSERVATIONS AND CONCLUS IONS ••5-1
~REFERENCES
FIGURES
APPENDIX A
1.0 INTRODUCTION
This report presents the resul ts of a seismic refraction
survey performed during June and July,1980,on the Upper
Susi tna Ri ver,Alaska,approximately 125 miles north of
Anchorage.The survey was performed under contract wi th
R & M Consultants as part of their subcontract with Acres
American Incorporated.
Most of the survey was performed on the abutments and
in borrow areas for the proposed earth and rockfill dam
near the confluence of Watana Creek and the Susitna River.
The locations of lines run at the Watana site are shown on
Figures 1 and 2.
The remainder of the survey was performed across a possible
saddle dam location adjacent to a proposed concrete dam at
Devil Canyon,approximately 27 miles west of the Watana
site.The locations of lines at the Devil Canyon site are
shown on Fi gure :3.
1.1 Purpose
The purpose of this survey is to.provide additional data
for the continuing feasibility studi.es for the Susitna
Hyq.roelectric Project proposed by the Alaska Power Au~
thority.This survey is to supplement borings,geologic
mapping,and previous geophysical surveys accomplished over
the past several years.
Line locations were selected by Acres American based on
previous studies.Line lengths,geophone spacing arid field
procedures were designed to investi~ate the nattire ahd
distribution of bsdrock arid overburden ma.terials.
1-2
1.2 Scope of Work
A total of 27,800 feet of seismic line was run as 11
separate traverses.Thirty-si x geophone spreads were
tested at 122 shot points.The scope of the field:work was
limi ted by several factors including planned duration of
the program,weather,and logistics.Several lines were
deleted or altered with the concurrence of Acres and R &M
field representatives.A few additional lines were added.
In particular,lines planned across the river at both dam
sites were not considered feasible because of the high rate
of flow at that time.Deleted line locations are 'shown on
Figures 1,2,and 3.
R&M personnel laid out and brushed all seismic lines and
provided a survey of relati ve elevations and spacing of
geophone and shot locations which had been flagged during
seismic testing.
The accumulated data were reduced and interpreted in
the Orange,California office of Woodward-Clyde Consul-
tants.Previous seismic studies by Dames &Moore,1975,
and by Shannon and Wilson,1978,were used as background
for the present interpretation.Field observations and the
judgment of a Woodward-Clyde Consul tants I geologist,who
was part of the survey crew,were included in the interpre-
tation.
-
2.0 DATA ACQUISITION
The majority of geophone spreads for this survey were 1,100
feet long with 100 feet spacing between geophones.Shorter
spacing of 10,20,25,40,and 50 feet were used where
terrain limited the length of a particular spread or where
greater detail was desired.For traverses of more than one
spread,end geophones on adjustment spreads were located at
the same point.
For most spreads,shots were placed at half-geophone
spacing beyond the end geophones and at the middle of the
line.Explosive charges of one pound provided sufficient
seismic energy for lines as long as 1100 feet.For about
half of the spreads,greater depths to bedrock required
shots at greater offsets from the ends to achieve re-
fraction from deeper interfaces.The largest offsets were
1,000 feet from the end geophone,resul tihg in a shot to
furthest geophone distance of 2,100 feet.Usually,an
explosive charge of two pounds was required for these
longer shots.For short lines explosives were not neces-
sary and a hammer and plate were used as the energy source.
The signature of seismic waves arriving at geophones from
each shot was recorded on a geoMetries/Nimbus model ES-
l210F 12-channel stacking seismograph.Recording gains
were selected by trial and error and filters were used when
background noise levels were high such as during heavy rain
or near the river.
The stacking feature of the seismograph employs an analogi
digital converter and an internal memory which stores wave
traces from each geophone separateiy.A digi tall analog
converter is then used to display the stored traces on an
2-2
oscilloscope.The input from multiple shots can be summed
into the memory and the summed or II stacked II traces dis-
played on the oscilloscope.Stacking of roul tiple shots
tends to enhance coherent seismic signals while the in-
fluence of random background noise is reduced by de-
structive interference.Stacking was used on this survey
for shorter lines where multiple hammer blows provided
seismic energy instead of explosives.The overall ampli-
tude of the single or stacked wave traces can be amplified
or reduced by the seismograph before a hard copy of the
record is produced by an electrostatic printer.
For each shot,a field plot was made of distance to each
geophone versus the time of arrival of the compressional
seismic wave picked from the recorded wave trace.This was
done to assure that sufficient information had been ob-
tained for later interpretation.At the same time,notes
were made as to terrain and exposed geologic features.
3.0 DATA REDUCTION PROCEDURES
Methods of reducing raw data to values suitable for inter-
pretation were generally those described by Redpath (1973).
These general techniques have been augmented to some degree
through our experience on past projects.
First,field records were reviewed and picks of arrival
times tabulated.Final time-distance plots were con-
structed to reflect changes in arri val times from those
used for field plots.These plots are shown in Appendix A,
Figures Al through AID.Apparent layering,apparent
seismic velocities,and variations in arrival times from
those expected from a particular layer,were used to direct
subsequent data reduction.
Representati ve "true"velocities were calculated from
differences in arrival times at each geophone from shots at
opposite ends of the line.Where sufficient data were
available,delay times were calculated beneath each geo-
phone for each layer.Layer thicknesses were then cal-
culated using the representati ve veloci ty.If sufficient
information was not available for rigorous delay-time
determination,approximation methods were used to estimate
depths.
In many cases,a layer which was well expressed on one
spread,or believed to be present from previous investi-
gations,would not be apparent on an adjacent spread.In
these cases,a judgment was made as to the continuation of
the layer,as a hidden layer or blind zone,beneath the
spread in question to produce the most geologically reason-
able interpretation.This often required adjustment of
other layer thicknesses to account for the total delay
time.
4.0 DISCUSSION OF RESULTS
The locations of the seismic lines are shown on Figures 1
through 3.Profiles along each seismic line illustrating
subsurface conditions interpreted from the survey are
presented as Figures 4 through 13.On these profiles,
layer thicknesses and surface topography are shown at a
twofold vertical exaggeration.This distortion is required
to illustrate the interpreted thickness of thin,shallow
layers.
Lines of contact between layers of differing velocities
vary on the profiles according to the confidence placed on
the interpretation.Solid lines represent a well con-
trolled contact with depths shown probably within 15
percent of the true total depth.Dots on the line repre-
sent points of control where the depth is well constrained
by the data.Dashed lines are less well controlled.Short
dashed lines with no control-point dots represent assumed
contacts based on information other than that resul ting
directly from data reduction.
The following paragraphs discuss the setting of each
traverse,the results of our interpretation,and anomalous
or ambiguous cond~t~ons which became apparent dur~ng data
reduction and subsequent review of data from borings,test
trenches,and surficial geologic mapping.
4.1 Traverse 80-1
This traverse consists of six 1,100 foot geophone spreads
and three 225 foot detail spreads.As shown on Figure 1,
the line e~tends northward about 3300 feet from the right
abutment downstream from the proposed Watana Dam,and then
northeastward an additional 3300 feet across the proposed
spillway alignment.Topography is relatively steep at both
ends of the line and relatively gentle elsewhere.
4 ....2
The interpreted profile for traverse BO-l is shown on
Figure 4.Bedrock velocities along the line appear to
be relatively uniform,ranging from 14,500 fps (feet per
second)to 16,000 fps.Intermediate layer velocities range
from 5,250 fps to 13,000 fps and shallow layer vetocities
from 1,300 fps to 3,600 fps.The lower velocities repre-
sent loose surficial materials and possibly,in part,
fine-grained lake deposi ts such as encountered in boring
DR-6 (the location of borings designated DR are shown in
u.S.Army Corps of Engineers [1979J).
At the southern end of the line,a 50-foot-thick layer of
10,000 fps material probably represents weathered bedrock.
Near the northern end of spread BO-lE,this layer thickens
to over 100 feet and may represent an anomaly similar to
that shown on Shannon and Wilson (1978),line 2 (SW2)to
the southeast.We understand that a prominent gouge zone
is exposed on the steep slopes near the anomaly shown on
SW2.The anomaly on line BO-IE may represent a cont~inu
ation of that zone in which case,its trend would be
approximately N40W.
A thick 13,000 fps layer is present near the center of the
traverse.It probably represents weathered diorite bedrock
but may be a different lithology such as volcanic rock
which has been mapped in the vicinity.Another possibility
is that the 13,000 fps material is part of a vertical
tabular fractured or al tered zone which extends from the
intersection of traverses 80-2 and SW2 where material of
the same velocity has been detected.Although the 13,000
fps zone is shown to be underlain by higher velocity mater-
ial on Figure 5,the higher velocity material may instead
be to the side.Addi tional refraction 1 ines or borings
will be required to resolve this possibility.
~
I
I
r-
!
4-3
The thin irregular edges of the relict channel discussed in
previous reports are apparent on spreads 80-IA and 80-IB •
.Channel fill beneath these lines,which is probably boul-
dery glacial detritus,ranges from 7000 to 9000 fps.The
configuration of the channel beneath line 80-lB is probably
much more complicated than shown on Figure 4.The profile
shows depths which are based on approximation reduction
methods because of the complexity of the time-distance plot
(Figure A-I,Appendix A)for which no reasonable mathe-
matical solution could be found.Depth to bedrock is shown
to be more than 150 feet but is probably highly irregular
and much shallower especially near the center of the line.
Boring DR-6 just southeast of the center of the line
encountered bedrock at a depth of 65 feet.
The channel appears to be the same as that documented by
the 1975 Dames and Moore survey and on lineSW3.It is
also well expressed on lines 80-2 and 80-6 which are dis-
cussed in later paragraphs.The southwestern edge of the
channel and the apparent thalweg are shown by dashed lines
on Figure 1.The eastern edge·of the channel appears to be
immediately north of line 80-7 and appears to be expressed
at the northern end of 80-8.
4.2 Traverse 80-2
Traverse 80-2 consists of five 1100 foot.spreads on the
right.abutment extending fro~near the toe of the proposed
Watana Dam,northward across the proposed spillway.It
roughly parallels Traverse 80-1 between 1,800 and 2,200
feet to the east and southeast (Figure 1).The topograp1:lY
is relativelY steep at the southern end and moderate to
gentte e+s~W1:l~re.The interpreted profil~for traverse 80-2
is s~own on Figur~S.
4-4
Bedrock velocities are similar to those of 80-1 ranging
from 14,000 to 17,000 fps.Intermediate layers consist of
thick 13,000 fps layers beneath the southern slopes and
channel fill at the northern end of the line ranging from
6,000 to 8,000 fps.Near surface velocity layers range
from 1250 to 2800 fps.
The lowest bedrock velocity encountered on the traverse is
beneath spread 80-2D and underlies an anomalously deep
portion of the relict channel.Borings DR-18 and DR-19,
northwest and southeast of the spread respectively,confirm
the depth to bedrock shown on the profile and indicate that
the rock in that area is highly fractured diorite with
apparent clay gouge zones.This low velocity zone may
represent a continuation of a shear zone known as liThe
Fins"exposed adjacent to the river to the southeast.The
trend of this possible continuation projects toward the
'northeastern end of spread 80-lB which,as previously
discussed,produced a highly irregular seismic record.
The 13,000 fps layer at the southern end of the traverse
appears to be weathered bedrock based on the shape and
location of the layer.Line SW2 which crosses the traverse
near its southern end (see Figure 1),also shows the 13,000
fps layer and the same depth to bedrock at the inter-
section.A 6,000 fps layer shown on SW2 was not detected
on 80-2.The 13,000 fps layer is shown on SW2 as contin-
uous for about 2400 feet parallel to the river.The shape
of the material shown on the profile of 80-2 (Figure 5)is
not inconsistent with the suggestion by Shannon and Wilson
(1978)that it may be involved in landsliding.
rI
~
4-5
The channel fill at the northeastern end of the line
consi sts of two distinct velocity zones similar to those
detected on traverse 80-1.The southern portion of the
fill ranges from 6,500 to 8,000 fps.Boring DR-20 appears
to have encountered this material southeast of the line
where it consists of saturated sandy gravels wi th finer
grained interlayers.Boring DR-18,northwest of the line,
appears to have penetrated lower velocity material detected
at the northeasternmost end of the traverse.This mater-
ial,ranging from 5,400 to 6,000 fps,appears to be mostly
sil ty sands and sandy silts wi th some clay and scattered
gravels and boulders.
Surficial materials near borings DR-18 and DR-20 appear to
be sandy silts.Seismic velocities of the surface layer
near the borings are generally less than 2,000 fps.
Velocities to the south along the traverse range are up
to 2,800 fps and interpreted as representing more gravelly
or better compacted sediments than those near the borings.
4.3 Traverse 80-3
Traverse 80-3 was run on the rugged steep slopes of the
abutments across the proposed upstream portion of the dam.
The profile,shown as Figure 6,is based on one 1,000 foot
spread on the left abutment and three spreads,1,000 feet,
265 feet,and 300 feet respecti vely,on the right abut-
ment.A proposed segment of the traverse across the river
was not considered feasible at the time of the survey due
to high water levels,and was therefore not performed.
~edrock is shallow on both abutments.On the south side,
beqrock appears to be of a uniform 15,000 fps velocity.
The top of the southern slope :i.s underlain py S,200 fps
material which may reflect frozen soil e~p6sed in a shallow
trench in that area.Farther down the slope,surficial
4-6
veloci ties drop to about 2,200 fps.This appears to be
very loose talus on the slope,at least at the center shot
point.The base of the slope is underlain by 7,000 fps
material which appears to be highly weathered bedrock.
Representative bedrock velocities on the north side range
from about 15,000 fps near the top to as high as 22,000 fps
lower on the slope.Surficial material on the north side
is generally about 15-foot-thick and between 1,500 and
2,200 fps on the upper slope.Surficial material is
thinner and lower in velocity near the bottom.Most of the
upper slope is covered with loose talus.
Geophone spread 80-3D was run parallel to the river along
the north bank.This line detected a 7,000 fps layer
50-foot-thick which probably projects beneath the river.
This layer was not apparent on spread 80-3C near the base
of the north slope.It appears as if 80-3C was run above a
resistant bedrock spur and that the 7,000 fps material is
present to each side of the spur near the base of the
slope.
Lines 80-4 and 80-5 which were planned across the river at
the proposed dam axis and beneath the upstream toe,re-
spectively,were not run due to high water conditions.It
may be possible to complete these lines after the river has
frozen.
4.4 Traverse ;80-6
This traverse consisted of one 1,100 foot spread and a
coincident shorter 600 foot detail spread across an appar-
ently anomalous topographic depression approximately 4,000
feet upstream from the proposed dam axis on the north side
of the river.The profile presented as Figure 7~shows the
edge of the relict channel discussed in conjunction wi th
Traverses 80-1 and 80-2.
"...
!
4-7
Bedrock veloci ty ranges from II,500 fps near the western
end of the line to 20,000 fps beneath the channel.The
channel appears to be filled with 7,000 fps material which
also is thinly distributed beneath the western portion of
the line.Overlying this is a layer of 2,300 fps material
and,in part,a thin surface layer of 1,100 fps material.
The increase in bedrock velocity across the traverse from
west to east may be related to effects of liThe Fins"shear
zone which is exposed about 700 feet southwest of the end
of spread 80-6A.This increase in bedrock velocity east of
the shear zone is also expressed on the 1975 seismic line
and on SW-3 which are both to the northwest of 80-06.
Progressi vely higher velocity zones on those three trav-
erses are roughly correlatible and appear to form bands
generally parallel to the shear zone.
The nearest borings to traverse 80-6 are more than I,000
feet away.The channel fill material is therefore inter-
preted to be similar to that interpreted for line SW-3 and
for traverses 80-1 and 80-2 as previously discussed.The
7,000 fps veloci ty of the fill is more uniform than seen
elsewhere and probably represents an averaging of both
higher and lower velocity materials such as saturat~d
alluvium and glacial detritus.
The Shannon and Wilson,1978,interpretation of nearby line
SW-3 shows a shallower channel containing 4,500 fps mater-
ial within the larger relict channel feature.This layer
can also be interpreted to underlie 80-6 based on the
tirne-distc111ce plot (see Appendix A,Figure A-5).However,
t.he present interpretat.ion of a slight thickening of the
2,360 fps layer is also reasonably consistent with.the
da.'ta.
4-8
Surficial materials are probably similar to those at depth
but less saturated.The 2,300 fps layer may also be finer
grained.The low velocity of the 1,100 fps layer suggests
it is very loose and probably dry.
4.5 Traverse 80-7
Traverse 80-7 consists of two 1,100 foot spreads oriented
north-south across the western end of Borrow Area D.The
line is shown on both Figures 1 and 2.Ground surface
rises gently to the north along the line.
Velocity analysis indicated that bedrock was uniformly
15,500 fps even though the time-distance plots showed
higher values.The differences are attributed to geometry
of the bedrock surface and not to lateral changes.The
interpreted profile for traverse 80-7 is shown on Figure
8.
The line appears to be located over the northeastern side
of the relict channel.Channel fill material ranges ~rom
7,400 to 9,000 fps.It is generally about 200-feet-deep
but is shallower near the north end.At the south end,it
may deepen to as much as 400 feet.Line SW3,which crosses
spread 80-7A near its northern end,shows a similar depth
and velocity for bedrock at that point.The velocity of
the channel fill is given as 7,000 fps on SW3.
Boring DR-26,which is located west of the north end of
line 80-7B,encountered silty sand,clayey silt,gravels,
and sandy silt with boulders at depths equivalent to the
channel fill material interpreted from seismic data.
The velocity of surface materials along the line appears to
be uniformly 1,850 fps.Several exposures along the line
indicate that the upper portion of this unit consists of
r
!'i""'"
I
I
4-9
boulder accumulations wi th little or no matrix.Borings
and trenches in the vicinity have encountered gravelly
sands below the immediate surface.
4.6 Traverse 80-8
The two 1,000 foot lines that comprise Traverse 80-8
extend southward from the end of line SW5 at the edge of
Borrow Area D near Deadman Creek across proposed Quarry
Source B as shown on Figure 2.The line crosses moderate
and then very steep topography southward.
Four continuous layers are interpreted on the profile
presented as Figure 9.These include a shallow 1,350 to
1,600 fps layer and intermediate velocity layers of 5,000
to 7,000 fps and 8,400 to 9,000 fps.Bedrock appears to
change laterally from 12,500 fps near the north end to
23,500 fps at the center,and to 16,500 fps n~ar th~south
end.
The highest bedrock velocity is at the middle of the
traverse wh~re the rock apparently forms a buried resistant
ridge.The b~drock surface may be as de~p as 500 f~et at a
point below the middle of spread 80-8A.At the north ~nd
of the line bedrock does not appear to be as deep as shown
in Shannon and Wilson,1978,line sW5.How~ver,this
location is near th~end of both lines and additional
control is lacking.
It does not appear l1k~ly that hard rock is near enough to
the surfac~to provide an aq~quate qUarry sourc~along the
line ot th~profile.We hp-ve no information as to possible
oqtcrops elsewnere within the designated area.The inter-
mediate velocity layers app~ar to be similar to those
tilling th~relict channel to the w~st as previously 4i6-
ClJ#Hied,'fhe 5,OPP to 7,agp tp§l~yeJ:"prOl:>ably J:"ep:f~sents 8,
4-10
younger episode of channeling and filling similar to that
shown on traverses 80-1 and 80-2.Both intermediate units
probably consist of saturated alluvial deposits and boul-
dery glacial detritus.
A number of test pits in the vicinity of the traverse
indicate that the shallow materials 1,350 to 1,600 fps
surface layers are highly variable.Most pits encountered
loose,unsaturated silty gravely sands.
4.7 Traverse 80-9
Traverse 80-9 was a single 1,100-foot-line at the western
end of Borrow Area E extending upslope from previous line
SW14.The present interpretation,shown on Figure 10,is
in good agreement with that line.
A relatively uniform mantle of low velocity material (1,100
to 1,800 fps)appears to cover the slope 30 to 50 feet
deep.Shallow exposures suggest that the 1,100 fps ma-
terial at the base of the hill is a loose gravel.Higher
on the hill,the surface is mantled by organic soil.
A higher velocity layer (6,000 to 7,250 fps)underlies the
surficial deposits and thickens northward.These vel-
ocities are similar to those of saturated alluvium and
glacial detritus found elsewhere.Bedrock with an approxi-
mate velocity of 15,000 fps,is about 100 feet below the
surface at the base of the hill and may be as deep as 300
feet at the north end of the line.
4.8 Traverse 80-11
This traverse was run north and west of Tsusena Creek near
the eastern end of Borrow Area E.The alignment was
changed from east of the creek when surface reconnaissance
showed that area to be underlain primarily wi th bouldery
glacial deposits.
4-11
Spread 80-11A was run from the bank of Tsusena Creek
northward 1,100 feet across gentle topography to the base
of a hill (Figure 2).A second 1,100 foot spread,80-11B,
was run from the center of the first in a northeasterly
direction.This line hd not been previously staked or
brushed and when surveyed later,was found to bend to the
north as shown on Figure 2.Two shorter detail spreads
(80-11C and 80-11D)were also run near the middle of spread
80-11A.
On the southern end of the traverse 80-11A,a 2,800 fps
layer of loose surficial deposits appears to be about 30
feet thick and thins to the north.This appears to be
underlain by a 11,000 fps weathered bedrock layer about 100
feet thick which also thins to the north.Bedrock velocity
beneath the area is between 16,000 and 17,000 fps.
In the northern part of the area the 11,000 fps layer
wedges out beneath an apparent relict channel filled with
5,000 fps material which may be loose saturated sands and
gravels.A 7,000 fps intermediate zone at the north end of
spread 80-l1A is not apparent on 80-1lB.Instead,the
northern part of 80-llB shows shallow bedrock beneath about
20 feet of 1,400 fps sur ficial deposits.The 7,000 fps
material may be similar to the relict channel fill detected
on lines previously discussed.
4.9 Traverses 80~12,80-13,and 80-15
These three traverses were run across a small lake and
on the adjacent slopes above the left abutment of the
proposed Devil Canyon Dam as shown on Figure 3.Traverse
80-12 consisted of a 250 fOot hydrophone spread across the
western part of the lake and two 500 foot geophone spreads
4-12
up steep adjacent slopes to the north and south.Traverse
80-13 consisted of a similar combination across the eastern
part of the lake.Traverse 15 was a single hydrophone
line,500 foot long,extending northwest to southeast
across the lake.
The profiles shown on Figures 12 and 13 indicate similar
bedrock velocities of between 16,800 and 18,800 fps.
Profile 80-12 shows a distinct intermediate layer beneath
the slopes of between 7,000 and 10,000 fps.This may be
highly weathered bedrock or glacial deposits.A 5,000 fps
intermediate layer beneath the relatively flat north end of
80-13,probably indicates water table in otherwise low
veloci ty sediments.Surficial deposi ts on the slopes are
generally between 1,400 and 2,200 fps.The 4,000 fps
indicated beneath the north-facing slope on line 80-13
probably represents partically frozen ground.
A layer of approximately 5,000 fps underlies the lake on
all three profiles.This is probably saturated soft
sediments which may be as deep as 50 feet near the center
of the lake as shown on profile 80-15.Time-distance plots
from all three spreads run across the lake are very ir-
regular and subject to alternative interpretations.Data
from spread 80-15 appear to indicate that high-velocity
bedrock directly underlies the saturated sediments beneath
most of the lake.The other two profiles,however,indi-
cate that only weathered rock is present beneath part of
the area.
The possibility of a shear zone trending approximately
east-west beneath the lake was suggested by Shannon and
Wilson (1978)based on results of line SW-17,which par-
allels 80-12,400 feet to the west.On that line,bedrock
4-13
velocities underlying 7,000 fps channel fill near the
center of the line were interpreted to be lower than
beneath the slopes to either side.Three of 5 borings
drilled along that line encountered highly fractured or
sheared phylltic bedrock.
The results of the present survey can neither confirm nor
deny the presence of a shear zone.Although the time-
distance plots appear to be anomalously irregular,reason-
able mathematical interpretations were obtained from the
data.Lower veloci ties were obtained for bedrock beneath
the lake than on the adjacent slopes (as on SW-17)but
the reason for these lower velocities is not clear from the
data.They may indicate sheared material or,alterna-
tively,dense fill material or weathered,surficially
fractured bedrock.
5.0 GENERAL OBSERVATIONS AND CONCLUSIONS
Materials represented by velocity layers interpreted for
this report have been assigned,at least in general terms,
where boring and test pit data have been available.In
areas where this control has not been available,similari-
ties in layering and velocities with better controlled
areas have allowed assignment of material types with a
reasonable degree of confidence.
In general,bedrock veloci ties near the Watana site vary
between 14,000 and 23,000 fps.Veloci ties of 18,000 to
23,000 fps are representative of hard,unfractured diorite
as exposed in the immediate site vicinity.Lower veloci-
ties indicate increasing degrees of fract~ring and weather-
ing if the rock is indeed diorite.These lower velocities
may also represent other lithologies such as metamorphic
zones or volcanics such as have been mapped on the right
abutment downstream from the dam.
Velocities as low as 10,000 fps in intermediate layers
over+ying higher velocity bedrock may represent highly
weathered diorite.Apparent layers of 13,000 fps material
found near the middle of traverse 80-1 and at the south end
of eO-2 have been interpreted as weathered pedrock but may
represent a different lithology.
Lateral changes in bedroCk velocity have been noted on
several lines for this and previo~s surveys near the
Wat&na site ~Th~se cha.nges appear to form ba.nd~of
in~+eaJ;ing velocity eastwarq from I'The Wins"shear g;<:H1.e as
-,-.-.<
pr_iently int~rpretedf aIld may al~o form nQrthwest tr~ngin9
b~nqs ta.rtber to the w~§t.Present d~ta,however,is
irusufficient to vertfy this pilrt.te;rfh
5-2
Portions of the relict channel at the Watana site have been
defined by the present interpretation.The channel is
apparent on traverses 80-1,80-2, 80-6,80-7,and 80-8.
Channel fill material ranges from 5,000 to 9,000 fps and
has been shown by borings to be highly variable but pre-
dominantly alluvial sands and gravels,bouldery glacial
sil ts and sands,and to a lesser extent lacustrine sil ts
and clays.Two episodes of channeling are apparent on
traverses 80-1, 80-2,and 80-8.Ma terials on traverses
80-9,and 80-10 with similar velocities appear to be
lithologically similar to those in the relict channel.
At the Devil Canyon site,the highest bedrock velocity
detected was nearly 18,000 fps.This is the velocity
reported for fresh phyllite in the area by Shannon and
Wilson (1978).Lower velocity bedrock interpreted from the
present survey may reflect weathering or lateral lithologic
charlges.
Intermediate layer velocities at the Devil Canyon site
range from 5,000 to 10,000 fps.Velocities as low as 7,000
fps could represent weathered bedrock in the metamorphic
terrain.The 5,000 fps layers interpreted from this survey
appear to be equivalent to the 7,000 fps layer on SW-17 to
the west of the lake.Borings in that area showed the
material to be predominantly sand with some gravel and
boulders.
Surficial deposits are highly variable in the area of the
survey and are therefore difficul t to discuss in general
terms.Surficial materials are best investigated with
short lines and small geophone spacing.Since most of the
lines for this survey used wide geophone spacing,the
information obtained about surficial layers is highly
~
i
r-
I
i
f"""!I
I
5-3
generalized.Most of the surficial velocities reported
herein are probably averages of several smaller distinct
layers and are more related to the distance from shot point
to the first geophone than to the velocity of any par-
ticular material.
Wi th regard to structure,two possible shear zones have
been interpreted from this survey.These are northwest
trending zones extending from the right abutment at the
Watana site and are discussed with respect to traverses
80-1,and 80-2 in earlier sections.Information regarding
a possible shear zone beneath the saddle dam site at Devil
Canyon was indeterminate.
The data from the present survey were sufficient to make
fairly definite interpretations.However,specific depths
and material types should be confirmed by borings in
cri tical areas.We suggest that when sufficient boring
control becomes available,that all three refraction
surveys be re-evaluated to more accurately portray con-
ditions between borings.
The interpretation resul ting from the present survey
are considered the most reasonable based on available
information.They are not the only interpreta tions
possible.The limitations of the seismic method and the
present data are discussed further in Appendix A and the
references.
REFERENCES
Dames and Moore,1975,Subsurface exploration,proposed
Watana Dam site on the Susitna River,Alaska:Report
for Department of the Army,Alaska District,Corps
of Engineers,Contract DACW85-C-0004.
Redpath,B.B.,1973,Seismic refraction exploration
for engineering si te investigations:u.S.Army
Engineer Waterways Experiment Station,Explosive
Excavation Research Laboratory,Livermore,California,
Technical Report E-73-4,55 p.
Shannon and Wilson,Inc.,1978,Seismic refraction survey,
Susitna Hydroelectric Project,Watana Dam site:
Report for Department of the Army,Alaska District,
Corps of Engineers,Contract DACW85-78-C-0027.
u.S.Army Corps of Engineers -Alaska District,1979,
Southcentral Railbelt Area,Alaska Upper Susitna River
Basin -Supplemental Feasibility Report:Appendix Part
I.
\/-;;;.
".)c~f ~:::J
r)~(J .\./))J.~,~(/'.WATANA DETAIL AREA /
~LOCATiON OF SEISMIC REFRACTIO
!/...-
I ,./'
N 3,234,000
N 3,230.000
N 3.232.000
N 3.226.000
39
FOG LAKES TRAVERSE
8j §§§.8..0 ~§
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SCALE:?1000
FIGURE I
2200 -
NOTES
I.LOCATION ACCURATE TO +
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2200~
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IAREA
IRACTION LINES
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SCALE IN MILES
Fog Lakes Refraction Traverse
lines 81-FL-1 to 81-FL-48
23
WATANA DETAIL AREA
(Figure 1 )
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-_-,"33 34 41 42--__-l:!"~
28 29 48
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PREPARED BY WOODWARD -CLYDE CONSULTANTS
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WATANA VI
APPROXIMATE LaC,
LINES OUTSII
FIGURE 2
FOG ···~~.EEK
SW"-;.:z:SW-12 '..
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~INITY MAP-~TION OF REFRACTION~E DETAIL AREA
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600
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_____13_00 ~
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LOCATION OF DEVIL l
SEISMIC REFRACTION
...
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FIGURE 3
80-1E
c
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w
2300 i North
2150
80-1H
12
2000
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1850
1700 -
1550
80-1F
..-'..-'
9500 ,.-,.-
14800
I.80-11 J
1 12
12 12
3600
16000
Compressional wave velocities in feet per second
Horizontal Scale:1 inch =300 feet
Vertical Scale:1 inch =150 feet
SEISMIC REFRACTION PROFILE 80-1
SHEET I OF 2
PREPARED BY WOODWARD-CLYDE CONSULTANTS
80-10
1600-?~--.!..~~__-""'---i
.--
13000
14800
2300
2150
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Q)......
c~
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1550
NOTE~
ELEVATIONS ADJUSTED TO TRUE VALUES
ACCORDING TO RaM CONSLlLTANTS,3/19/81.
FIGURE 4 a
2150
2300
co.
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w
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1850
1700
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80-1G
I~-I112
- - ?
16000[
-"
80-18
9000
----------14800
Compressional wave velocities in feet per secone
Horizontal Scale:1 inch =300 feet
Vertical Scale:1 inch =150 feet
SEISMIC REFRACTION PROFILE 80-1
SHEET 2 OF 2
)ODWARD-CLYDE CONSULTANTS
2300
80-1C
2150
2000
1850
12
?
••••
9000
1----------o
I
I
14500
1700
I
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!feet per second
I .
~OO feet
feet
1550
NOTE:
ELEVATIONS ADJUSTED TO TRUE VALUES
ACCORDlNG TO RaM CONSULTAN TS,3/19/81.
FILE 80-1
FIGURE 4 b
13000
c
.Q
+-'co
[;
u.J
-
2450
2300
2150
2000
1850
North ~
-_.----
80-2A
•/
/
/
/
/
,;•/
/
,/
./
/'
,/
,/......
16700
15700
80-28
1690
Compressional wave velocities in feet per second
Horizontal Scale:
Vertical Scale:
1 inch =300 feet
inch =150 feet
ODWARD -CLYDE CONSULTANTS
SEISMIC REFRACTION PROFILE 80-2
SHEET I OF 2
Ir second
~'-.:..-
80-2
2450
•
N35E-..
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Abuts 80-28 80-2C 80--2D
/
2300
+-'12 1CIJ
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CIJe
2000 :..J
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1850 139(
-,
Compressional wave velocities in
Horizontal Scale:1 inch =300 '
Vertical Scale:1 inch =150 fee
SEISMIC REFRACTION PF
SHEET 2 OF
DWARD-CLYDE CONSULTANTS
80--20
2450
80-2E
I
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13900
15380
2300
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2150 .Q
1400 +-'co>Q)
w
5970
2000
1850
NOTE:
ELEVATIONS ADJUSTED TO TRUE VALUES
ACCORDING TO RaM CONSULTANTS,3/19/81.
ACTION PROFILE 80-2
EET 2 OF 2
FIGURE 5b
North ---...
2100
80-3A
1900
2000
,
co
of-'roa;
W
1800
1700
1600
1500
1400
15000
\-\
\
\
\
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eneno
U
~i
12 I'
Elevation 1464'/1'~--=.;.:;;...:...::;...:..--'----~..,
/-/"
~....../7000/
/
".
./
........20000
Compressional wave velocities in feet per
Horizontal Scale:1 inch =200 feet
Vertical Scale:inch =100 feet
SEISMIC REFRACTION PROFI LE
PREPARED BY WOODWARD·CLYDE CONSULTANTS
Crosses SW2 2100
80-38
14800 2000
1900
22200
-3C
I .
1800
+-'Q)
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20000 +-'
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1700 UJ
1600
:1050
i
20000 ~
f second,
1500
1400
NOTE:
ELEVATIONS ADJUSTED TO TRUE VALUES
ACCORDING TO R8 M CONSULTANTS,3/19/81.
I
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~80-3
I
FIGURE 6
80-6A
......-"-...........
---.---.
1......1------------------80--68 ----
-.-.-
7000
----.
11500
___e - _-.....__._---
'--.----.---......---'---,-:~------
"""........
-.
2300--
-
2100
2200
_.-
-..---
2150
co
+-'
ctl
~
UJ
2050
15000
2000
1950
-
1900
Compressional wave velocities in feet per second
Horizontal Scale:1 incA.=100 feet
Vertical Scale:1 inch =50 feet
SEISMIC REFRACTION PROFILE 80-6
I~OOOWARO-CLYOE CONSULTANTS
N78E~
2200
~-6B ~I
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+-'co•>\~w
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"'-.---.------..........1950.........
-20000
1900
.second
NOTE:
ELEVATIONS ADJUSTED TO TRUE VALUES
ACCORDING TO RaM CONSULTANTS,3//9/81.
80-6
FIGURE 7
North~
2400
2300
80-7A
Crosses SW3-----I
2200
12 1
7400
c:
.Q
+-'co
~
W
2100
2000
1900
·1806 /
9000
Compressional wave velocities in feet per second
Horizontal Scale:1 inch =200 feet
Vertical Scale:1 inch =100 feet
SEISMIC REFRACTION PROFILE 80-7
WARD-CLYDE CONSULTANTS
80-78
1000'from Sta
70+00,1975 line 2400
2300
7400 8200 2200
I
I
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QJ
~
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I 0
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I
I
1900
......~-,
1800
~cond NOTE:
ELEVATIONS ADJUSTED TO TRUE VALUES
ACCORDING TO R8 M CONSUL TANTS ,3/19/81.
80-7
FIGURE 8
2300
2200
80-88 80-8A
1E
2100
2000 7000
+-'w ""W
"l-e
c'1600./0
'.j:i /'ro>/"ClJ
w 1900 /--/
1800
1700
1600
Compressional wa\i
Horizontal Scale:
Vertical Scale:1 i
SEISMIC REF
D BY WOODWARD-CLYDE CONSULTANTS
2300
End of line SW 5 -
5000
,/'
/
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-0.../~8400
2200
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2000
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1900 LU
--7 1800/e---
•
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~e
12500
-'i~1600 ,,,,,,,,,'
anal wave ·velocities in feet per second
I Scale:1 inch =200 feet
~cale:1 inch =100 feet
NOTE:
ELEVATIONS ADJUSTED TO TRUE VALUES
ACCORDING TO RaM CONSULTANTS,3/19/81.
C REFRACTION PROFILE 80-8
FIGURE 9
1900 1900
18001800
1700 1700
7250
+-'+-'Q)Q)Q)End of line SW14 Q)"+-"+-
c'1600 1600 c'"0 0
+-'+-'co co>>Q)Q)
w w'"
1500 ~1500r-.........
!".......
.........
..........6000
r-.................
........
.........
1400 15000 ~1400
~
-
1300 Compressional wave velocities in feet per second
Horizontal Scale:1 inch =200 feet
Vertical Scale:1 inch =100 feet
Note:Elevations adjusted to true values
according to R&M Consultants,3/19/81
SEISMIC RE:FRACiION PROFILE:80-9
FIGURE 10
North .............
80-11A
1500
--
1000
-- ---
I--,-----I---T ---I
I
I
11000 I -------r---I..--I...--I 16000--I
/'!
,,/'"
.-/
16000
2800
--------1450
1400
Crosses 80-11 B,C,D -~---;----------
-
5
oJ
1J
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w
1350 -
-----
80-11 B
5000
~N30E ---+--
16000
_..-~OOO ~...--
-----------....-....-----~-----~
---.~----"'>----------------
-
Ir Crosses 80-11 A
~N40E-+--
1500
1400
1450
,--
Compressional wave vel'Z>cities in feet per second
1350 -
Horizontal Scale:1 inch =100 feet
Vertical Scale:1 inch =50 feet
SEISMIC REFRACTION PROFILE 80-11
fOODWARD -CLYDE CONSULTANTS
1500
12
--
1000
---------
5000
- - - - -7--
,,/
..-/
..........------
7000
--
17000
1450
,1400
1350
~North --..
1500
I
I
('
-.....--•
1400
--.-~-----
16000
-
1450
1400
+-'Q)
Q)
'+-
second
E 80-11
1350
NOTE:
ELEVATIONS ADJUSTED TO TRUE VALUES
ACCORDING TO R8I M CONSULTANTS,3/19/81.
FIGURE II
N7W--.
1500 80-128 80-12A
1450
+-'1400
Q)
Q)
'+-
c'
0
+-'co>Q)
UJ 1350
1300
1250
1400
16800
Crosses 80-15 ~
Lake EI.1327'I
I
I /-
1 /,
II
10000 1/--......,II,/I'---,.,./
1
16800
1300
+-'Q)
Q)
'+-
c'
0'p
co
~
1250 UJ
1350
M.....
Ig
N.....
I S80E--'g
1350 III 80-15~lelul Lake EI.1327'"'--.
LAKE
+-'1300
Q)
Q)
'+-5Q90
c'
.Q
+-'co>Q)
UJ 1250
16500
1200 1200
I WOODWARD-CLYDE CONSULTANTS
SEISMIC REFRACTION PROFILES 80-12 a 80-1~
80-12C
12
1500
1450
1400 +-'OJ
OJ'+-
c:
0',p
co>OJ
1350 UJ
15~
17'I
1300
1250
Compressional wave velocities in feet per second"
Horizontal Scale:1 inch =100 feet
Vertical Scale:1 inch :=50 feet
Notes:Elevations adjusted to true values--
according to R&M CClDsultants,3/19/81
NOTE:
ELEVATIONS ADJUSTED TO TRUE VALUES
ACCORDING TO RaM CONSULTANTS,3/19/81.
I
i2 a 80-15
FIGURE 12
1450
co
'.;::J
ctl
5)
LU
1400
1350
1300
1250
16800
80--13C
,,,,,,,,,,,'
N7W~
80-138
1/Crosses 80-15
I
12300
Compressional wave velociti
Horizontal Scale:1 inch =
Vertical Scale:1 inch ==51
SEISMIC REFRACTION PROFILE 80-13
Y WOODWARD.CLYDE CONSULTANTS
80-13A.
1450
I
1[1 wave V:I,OCities in feet per~econd
I ale:1 inch =100 feet
Ie:1 inch =50 feet
1400
1350
1300
1250
co
+-'ctl
~
LU
~ILE 80-13
NOTE:
ELEVATIONS ADJUSTED TO TRUE VALUES
ACCORDING TO RBi M CONSULTANTS)3/19/81.
FIGURE 13
-
APPENDIX A*
*This appendix deleted from Task 5,Appendix H.Refer to project files
for Woodward-Clyde Consultants report.
r
I
I '-
APPENDIX I
SEISMIC REFRACTION SURVEY-1981
SUSITNA HYDROELECTRIC PROJECT
SEISMIC REFRACTION SURVEYS
1981
Submitted to
R &M Consultants
5024 Cordova
Anchorage,Alaska 99502
6 January 1982
R &M Consultants
5024 Cordova
Anchorage,Alaska 99502
Attention:Mr.Gary Smith
Gentlemen:
SUBJECT:SUSITNA HYDROELECTRIC PROJECT
SEISMIC REFRACTION SURVEYS -1981
Enclosed are five copies of the sUbject report which docu-
ments geophysical work in support of site engineering
studies during 1981.At the request of Acres American
Incorporated,we are also sending five copies directly to
their office in Buffalo,New York.
We have enjoyed working with you on this project and hope we
can be of further service in the future.If you have
questions regarding the material contained in this report,
please call at your convenience.
-
Very truly yours,
YJ~L~
Dennis E.Jensen
Project Geologist
DEJ/md
Enclosure
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~Jan D.Rietman,Ph.D.
Deputy Director of Geophysics
TABLE OF CONTENTS
LETTER OF TRANSMITTAL
TABLE OF CONTENTS
LIST OF ILLUSTRATIONS
1.0 INTRODUCTION ..1-1
1.1
1.2
Purpose.
Scope of Work ..
1-1
1-2
2.0
3.0
DATA ACQUISITION AND REDUCTION .
LIMITATIONS .
2-1
3-1
4.0 SPRING TRAVERSES ...............4-1
4.1 Traverse 81-1.4-1
4.2 Traverse 81-2.4-2
4.3 Traverse 81-3.4-3
4.4 Traverse 81-4 ..4-3
4.5 Traverse 81-5.4-4
4.6 Traverse 81-6........4-4
4.7 Traverse 81-7......4-5
4.8 Traverse 81-8 .......4-6
4.9 Traverse 81-9.4-6
4.10 Traverse 81-10.4-7
4.11 Traverse 81-11.4-8
4.12 Traverse 81-12.4-8
5.0 SUMMER 1981 SURVEYS ..5-1
5.1 Traverse 81-13.5-1
5.2 Traverse 81-14 ..5-2
5.3 Traverse 81-15......5-3
5.4 Traverse 81-16 ..5-4
,....,..
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Table 1
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
Figure 15
Figure 16
Figure 17
Figure 18
Figure 19
Figure 20
Figure 21
Figure 22
Figure 23
LIST OF ILLUSTRATIONS
1980 -1981 Seismic Refraction Line Data
Location of Seismic Refraction Lines -
Watana Detail Area
Watana Vicinity Map -Approximate Location of
Refraction Lines Outside Detail Area
Location of Devil Canyon Seismic
Refraction Lines
Seismic Refraction Profiles 81-1 and 81-2
Seismic Refraction Profiles 81-3,81-4,and 81-5
Seismic Refraction Profiles 81-6 and 81-7
Seismic Refraction Profiles 81-8 and 81-9
Seismic Refraction Profiles 81-10 and 81-11
Seismic Refraction Profile 81-12
Seismic Refraction Profile 81-13
Seismic Refraction Profile 81-14
Seismic Refraction Profiles 81-15 and 81-16
Seismic Refraction Profiles 81-17 and 81-18
Seismic Refraction Profile 81-19
Seismic Refraction Profiles 81-20 and 81-21
Seismic Refraction Profile 81-22
Fog Lakes Seismic Refraction Profiles -Sheet 1
Fog Lakes Seismic Refraction Profiles -Sheet 2
Fog Lakes Seismic Refraction Profiles -Sheet 3
Fog Lakes Seismic Refraction Profiles -Sheet 4
Fog Lakes Seismic Refraction Profiles -Sheet 5
Fog Lakes Seismic Refraction Profiles -Sheet 6
Fog Lakes Seismic Refraction Profiles -Sheet 7
1.0 INTRODUCTION
This report presents the resul ts of geophysical surveys
performed during the spring,summer,and fall of 1981
on the Upper Susitna River,Alaska,approximately 125
miles north of Anchorage.These surveys were performed
under contract with R &M Consultants (R &M)as part of
their subcontract with Acres American Incorporated (AAI).
The 1981 geophysical program was essentially a continuation
of surveys performed during 1980 under the same contract.
Results of the 1980 surveys were submitted to R &M
in a report dated 19 December 1980.Interpretations
included in this report are based in part on the 1980 work,
on previous seismic refraction surveys (Dames and Moore,
1975;Shannon and Wilson,1978),and on limited boring and
surface mapping information.
Locations of all refraction traverses from 1975 through
1981 are shown in Figures I,2,and 3.Figure 1 covers the
immediate area of the proposed Watana Dam site and Figure 2
shows line locations outside of the immediate site area but
in the same vicinity.Figure 3 shows line locations near
the proposed Devil Canyon Dam site.
1.1 Purpose
Geophysical surveys from 1981 and from past years were
accomplished as part of feasibility studies for the
Susitna Hydroelectric Project proposed by the Alaska Power
Authority.Seismic refraction and limited magnetometer
surveys were intended to investigate the nature and
distribution of bedrock and overburden materials and to
supplement data from other sources such as borings and
geologic mapping.
1-2
For all surveys run during 1980 and 1981,line locations
were specified by AAI.Some of the 1981 locations were
recommended by Woodward-Clyde Consultants at the close of
the 1980 season,and incorporated in the 1981 program.
1.2 Scope
A total of 72,900 ft of refraction line was run in 1981
during three separate field efforts (spring,summer,and
fall)to bring the two-year total to approximately 100,000
linear feet.In addition,approximately 3,000 ft of
magnetometer line was run near Devil Canyon in an unsuc-
cessful attempt to detect buried mafic dikes.
The spring seismic refraction survey consisted of 21,900 ft
of line at 12 locations (Lines 81-1 through 81-12)across
the river and adjacent low-lying areas near the Watana site
(Figures 1 &2).Field work was accomplished between 1
April and 14 April 1981 when the river was frozen.The low
water level and low water velocity plus access afforded by
ice allowed refraction surveys to be run in areas where
they would be infeasible later in the year.A draft report
of the results of the spring work was submitted to R & M
dated 18 June 1981.
A total of 22,200 ft of refraction line was run during the
month of July as 10 separate traverses (Lines 81-13 through
81-22).Nine of these were run at the Watana site (Figure
1),some as continuations of existing lines.One traverse
was run on the proposed south abutment at Devil Canyon
(Figure 3).
From 26 October to 15 November,1981,a 28,800 ft traverse
was run from rock outcrops near the proposed Watana south
abutment to a point approximately 5 miles to the east.The
r
1-3
locations of lines 81-FL-1 through 81-FL-48 are shown on
Figures 1 &2.This traverse crossed an area of suspected
buried channels in the Fog Lakes area.
The alignments of all traverses were flagged by R &M
or AAI personnel prior to refraction surveying.During
refraction work,the location of all shot points and
geophones were flagged.The coordinates and elevations of
each of the shot and geophone points for spring and
summer traverses were subsequently surveyed by R &M.For
the fall work (Fog Lakes)R &M provided coordinates and
elevations at all turning points and breaks in slope.
Data for all seismic refraction traverses accomplished
during 1980 and 1981 are summarized in Table 1.The table
includes line numbers used in this report,line numbers
used by R &M for coordinate and elevation surveys,presen-
tation data,line configuration data,and comments.This
report discusses the interpretation of 1981 traverses in
detail and references 1980 lines where they are in proxi-
mity to the 1981 survey lines.
2.0 DATA ACQUISITION AND REDUCTION
Field procedures used during the 1981 season were similar
to those of the 1980 survey (Woodward-Clyde Consul tants,
1980).A Geometries/Nimbus model ES-1210F twelve-channel
stacking seismograph and an explosive energy source was
used for all lines.Line lengths and geophone spacing
varied as discussed later in separate sections.
Data reduction for the 1981 surveys was accomplished in a
similar manner as for the 1980 lines,essentially following
the procedures of Redpath (1973).Rigorous delay time
methods were used for only a few lines for which data was
sufficient and too complex for adequate interpretation by
approximation methods.
Time-distance plots of the data are included in Appendix A
(spring surveys),Appendix B (summer surveys),and Appendix
C (fall-Fog Lakes surveys).Interpretation of these
lines are shown as Figures 4 through 23 and are discussed
in Sections 4.0,5.0,and 6.0.These sections discuss the
setting of each traverse,our interpretation,and anomalous
or ambiguous conditions which became apparent during data
reduction and subsequent review of all available data.
Our confidence in the contacts between layers of differing
velocities on the figures is variable.Solid lines repre-
sent well controlled contacts with the depths shown prob-
ably within 20 percent of the true total depth.Dots on a
line represent depths calculated by the delay time method
or by approximation techniques.Dashed lines are less well
controlled with an estimated possible deviation from true
depths on the order of 30%.Queried dashed lines are
2-2
assumed contacts that are based on assumed velocities and
information other than that resul ting directly from data
reduction,or that are inferred by the data but are not
mathematically explicit.
3.0 LIMITATIONS
Seismic refraction is a widely used and well suited
exploration tool for engineering projects but is subject to
certain limitations which should be kept in mind when
evaluating the interpretations presented in the following
sections.The effects of inhomogeneities,irregular
contacts,"blind zones"and hard-over-soft conditions are
discussed below.Other limitations which result from the
site environment and from the specified scope of these
surveys apply particularly to seismic work performed at the
Susitna sites.
The seismic refraction technique depends upon measuring the
first arrival of a seismic wave at geophones placed on the
ground surface progressively further from an explosive
charge or other seismic source.Arrivals at nearest phones
generally indicate travel directly through low-density
surface materials.At points further from the source,the
seismic wave arrives sooner than would be expected from
travel through surface materials,having traveled in part
through deeper,more dense,and therefore higher velocity
layers.If subsurface layers are uniform,horizontal and
the seismic velocities progressively increase with depth,a
mathematical model can be developed from the arrival time
data that approximates actual conditions.Several condi-
tions exist in nature,however,which make interpretation
of the data less precise and introduce ambiquity into the
model.
In ideal situations,plots of arrival times versus distance
(see Appendices Ai B,and c)produce straight lines,the
inverse slopes of whi¢h represent the seismic velocity
of the subsurface material.Deviations of the data from
straight lihes indicate inhomogeneity within layers i
3-2
irregular layer contacts,or inaccuracy in identification
of first arrival time.Sufficient data is seldom available
to distinguish amoung these possibilities.It is also
difficul t to determine if irregulari ties occur in near-
surface layers or at depth.In many cases,the data
resulting from local or lateral velocity changes can also
be interpreted as contact irregularities.
Thin layers at depth also present a problem.Ideally each
layer is represented on a time-distance plot as a separate
straight line.Thin layers may produce no indication of
their existance in the data regardless of the detail of the
survey.Such lIblind zone ll cases can affect the calculated
depth to deeper layers,such as bedrock,by a theoretical
maximum of 30 percent.
Layers with seismic velocities less than overlying layers
are not de tee tab 1e by ref rae t i on .Th iss i t ua t ion i s
suspected to exist in several areas,at the Watana site in
particular,where less dense sediments may underlie frozen,
more dense ground.Non-seismic information,such as boring
data,is required to resol ve hard-over-soft condi tions,
enabling correction of the refraction model,which is
otherwise likely to be in error by as much as 30 percent
for the depth of deeper layers.
Several conditions occur which preclude collection of the
optimum quantity and quality of data.These include
weather,ground conditions and,of course,the time
available to resolve operational problems which may arise.
For the Susitna work,field data reduction was performed to
assure the sufficiency of results from each line.In some
cases,however,time and budget constraints precluded
running additional lines which may have resolved some
uncertainties.
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3-3
In interpreting data which is less than straight forward,
the tendency is to produce as simple a model as possible
wi thout violating the restraints of the data.In these
cases,the experience and judgement of the interpreter is
important in producing a geologically reasonable picture.
The presence of an experienced geologist during shooting of
the lines and during interpretation,combined with the
results of previous investigations,increased the likeli-
hood that profiles presented herein reflect a fairly
accurate model of existing conditions suitable for evalua-
tion of the feasibility of the project.Further explora-
tion is required to resolve the uncertainties identi-
fied during these surveys.
4.0 SPRING TRAVERSES
The twelve traverses (lines 81-1 through 81-12)run during
April each crossed the Susitna River,which was almost
completely frozen at the time.Geophones at ice locations
were placed in holes bored through the ice to soil or,in
some cases,water.The phones were then firmly affixed to
the soil or river bottom by weights.Explosive charges
were detonated away from the river to provide the seismic
energy source.
During the surveys,ice thickness ranged up to four feet
with only a few open leads.The Susitna River was at its
low point for the year but still retained sufficient
velocity to interfere with seis~ic signals.Explosive
charges up to 20 Ibs were required to overcome the river
noise in some cases.Also,seismic signals traveling
through the ice at 11,000 fps (feet per second)often
masked first arrivals through shallow,less dense sedi-
ments.
The locations of lines 81-1 through 81-6 are shown in
Figure 1.Lines 81-7 through 81-12 are shown in Figure 2.
4.1 Traverse 81-1
This traverse consists of one 1,000 ft geophone spread and
three shotpoints.The line crosses the Susitna River near
the mouth of Deadman Creek.The south terminus is at the
base of the steep slope on the southern bank of the Susitna
River while the northern terminus is at the toe of the
slope at the northern side of the valley.The southern
third of this line is over the ice-covered Susitna River.
The interpretated profile for traverse 81 ...1 is shown
in Figure 4.Bedrock has a oalculated velocity of 16,700
fps.Bedrock appears to be very near the $urface at the
4-2
southern end of the profile and reaches a depth of about
120 ft near the northern end of the profile.There is a
bedrock high in the center of the profile which brings
bedrock to within 70 ft of the surface at that point.
An average velocity of 4,600 fps was found for the sur-
ficial materials.In our experience,this velocity is
typical of recent river deposits of varying saturation and
grain size.
4.2 Traverse 81-2
This traverse consists of two 1,000 ft spreads and six
shotpoints.The line setting is similar to that of
traverse 81-1 but is 3,000 ft further west,downstream.
The northern half of the traverse was over the active river
channel at the time of the survey.Ri ver ice with a
veloci ty of about 11,000 fps ,effectively masked the
arrivals from the surficial materials under the river.
The interpreted profile for traverse 81-2 is shown in
Figure 4.The calculated bedrock velocity on this profile
averages about 16,000 to 18,000 fps but is not well con-
strained due to the masking effect of the ice.Bedrock is
near surface on the south end of the profile and becomes
deeper towards the north to a postulated depth of about
150 feet.There appears to be a bedrock high simi lar to
that noted on profile 81-1,which brings bedrock to within
100 ft of the surface.
Surficial layer velocities vary from 5,000 fps on land to
possibly 8,000 fps under the river.These velocities
probably represent recent water saturated ri ver deposits.
4-3
4.3 Traverse 81-3
This traverse consists of one 500 ft spread and two shot-
points.The line crosses the Susitna River approximately
3,000 ft downstream from traverse 81-2 in the area where
the ri ver and valley are narrow.The southern traverse
terminus is on exposed bedrock and the northern terminus is
near the base of steep northern valley slope.
The interpreted profile for traverse 81-3 is shown in
Figure 5.Ice velocities of 11,100 fps were encountered.
The bedrock velocity and depth is unknown.A minimum depth
calculation indicates there is probably at least 50 ft of
5,000 fps overburden under the center of the river.The
bedrock gradient noted on the upstream profiles (81-1 and
81-2)suggests that the probable depth is more likely to be
at least 100 ft.
4.4 Traverse 81-4
This traverse consists of one 1,100 ft spread and three
shotpoints.A prominent structural feature on the north
abutment,the II Fins II,trends toward the location of the
line.Rock is exposed near both ends of the line.
Virtually the entire length of the line is over the ice-
covered river.
The interpreted profile for traverse 81-4 is shown in
Figure 5.Bedrock appears to be shallow and to have a
relatively low veloci ty of 14,000 fps.This velocity is
similar to that measured across the IIFins"on the north
abutment (Shannon and Wilson,1979,and line 81~15,this
report).It is also possible that the 14,000 fps material
is unusually high velocity frozen gravels and boulders
derived from local talus slopes and that competent bedrock
may be present at a greater depth.A minimum thickness
calculation was made which assumed a higher bedrock
4-4
veloci ty (e.g.,17,000 fps).This calculation shows that
the depth of such high velocity material would have to be
greater than 120 feet.This deeper contact places bedrock
at an elevation similar to that both upstream and down-
stream from this traverse.It is also possible that the
boulder deposit,which is exposed at the surface,has
approximately the same seismic velocity as underlying
weathered rock.In this case it would not be possible to
detect the contact by refraction.
A thin wedge of surficial materials with an average
velocity of about 6,500 fps may be as thick as 35 ft near
the north terminus of the line.A similar wedge appears to
be present at the south end.
4.5 Traverse 81-5
This traverse consists of one 650 ft spread and three
shotpoints.The line crosses traverse 81-4 and is slightly
farther downstream for most of its length.
The interpreted profile for traverse 81-5 is shown in
Figure 5.The calculated apparent bedrock velocity of
12,000 fps is very low but not inconsistant with the 14,000
fps of velocity on line 81-4.The small difference could
be due to anisotropy across a linear fracture zone or to
inhomogeneity of the boulder deposit.If present,higher
veloci ty rock (1 7,000 fps)would probably be over 100 ft
deep.
Thin surficial materials appear to be as thick as 15 ft at
the north terminous of the traverse.
4.6 Traverse 81-6
This traverse
shotpoints.
consists of one
The line crosses
500 ft spread with two
a narrow portion of the
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4-5
Susitna River under the upstream shell of the proposed dam.
Both ends terminate at the rock walls of the Susitna
Ri ver valley.The traverse connects the two segments of
traverse 80-3 (Woodward-Clyde Consultants,1980).
The interpreted profile for traverse 81-6 is shown in
Figure 6.The bedrock velocity and depth is unknown from
the present data because of the masking of first arrivals
from the bedrock refractor by direct arrivals through the
river ice.Delayed arrival times at the end-points of the
present line suggest there is about 30 to 40 ft of over-
burden near the river banks.Minimum depth calculations
as suming the higher velocities interpreted for the rock
slopes (line 80-3)suggest that the overburden is at least
60 ft thick near the center of the river.This interpreta-
tion is similar to that of Dames and Moore (1975)for a
line across the river at about the downstream toe of the
proposed dam.
4.7 Traverse 81-7
This traverse consists of three spreads,each about 1,000
ft long,and a total of nine shotpoints.The line crosses
the river near the downstream limit of Borrow Area E.The
Susitna River divides into several branches with the main
course near the north terminus of the traverse.
The interpreted profile for traverse 81-7 is shown in
Figure 6.Bedrock has a velocity which varies from 19,000
fps at the south terminus to 15,000 fps at the north
terminus.bepth to bedrock is typically 100 ft deep.The
bedrock surface has a gently undulating interface.The
bedrock depth appears to increase near the north terminus
of the line and correlates well with previous line SW-14
which is located about 1,000 ft to the northeast of line
81-7.
4-6
The surficial materials,probably saturated recent river
deposits,have velocities of about 5,000 fps.There is no
evidence in the data for an intermediate velocity layer
although previous lines in the area indicate this is
possible.A thin,undetectable layer underlying the 5000
fps layer with a velocity of 7,000 to 9,000 fps (typical of
glacial materials elsewhere),if present,could cause an
over estimation of overburden thickness by about 30 per-
cent.
4.8 Traverse 81-8
This traverse consists of three spreads,totaling about
2,500 ft long,and six shotpoints.The line crosses the
river valley about 5,000 ft downstream from traverse 81-7.
The eastern end of the profile crosses the active river
channel.
The interpreted profile for traverse 81-8 is shown in
Figure 7.Bedrock velocities range from 15,000 fps at the
west end of the line to 18,000 fps over most of the line.
The depth to bedrock typically varies from 50 to 100
feet.
The surficial sediments have velocities of 3,800 fps to
4,800 fps,suggesting only partial saturation.As in
traverse 81-7,an intermediate velocity layer,if present
as a hidden layer,could decrease the interpreted low
velocity overburden thicknesses and increase depth to
bedrock by up to 30 percent.
4.9 Traverse 81-9
This traverse consists of two spreads about 1,000 ft.long
and six shotpoints.This line crosses the Susi tna Ri ver
about 2 miles downstream from traverse 81-8.The line
4-7
crosses the river at its northwest terminus.
ice prevented complete data acquisition.
Thin,unsafe
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The interpreted profile for traverse 81-9 is shown in
Figure 7.Bedrock velocities range from 14,000 fps at the
southeast end of the line to 18,000 fps elsewhere.The
depth to bedrock varies from 100 to 180 feet.The deepest
portion is under the center of the valley.
An intermediate layer having a velocity of about 6,500
to 7,500 fps occurs under the entire line.This layer
probably represents older and more consolidated gravels
possibly of glacial origin.Recent surficial materials,
probably alluvial sands and fine gravels,form a thin
veneer,20 to 30 ft thick,with velocities of 3,800 to
4,800 fps.
4.10 Traverse 81-10
This traverse consists of two spreads,each about 1,100 ft
long and six shotpoints.The line crosses the valley at a
westward bend of the river about 8 miles downstream from
the proposed dam.The south~rn end of the line crosses the
river.
The interpreted profile for traverse 81-10 is shown in
Figure 8.No bedroCk velocities were observed on this
traverse.Minimum depth calculations show that the depth
to bedrock is probably greater than 300 ft based on an
assumed velocity of 18,000 fps.Lower assumed bedrock
v~locities would produce a shallower calculated depth.
An intermediate layer velocity of 8,300 fps to 9,500 fps
occurs under the entire line.The depth to this layer,
which appears to be well consolidated or possibly frozen
glacial deposits,decreases from about 70 ft at the north
4-8
end of the traverse to 10 ft at the south end.
materials have velocities of about 4,000 fps.
Surficial
4.11 Traverse 81-11
This traverse consists of three spreads and nine shot-
points.Two spreads are about 1,000 ft long while the
third is 700 ft long and offset from the other two.This
line is about 6,000 ft downstream from traverse 81-10 and
crosses the Susitna River bottom lands.The center section
of the line crosses the river.
The interpreted profile for traverse 81-11 is shown in
Figure 8.Bedrock appears to be about 400 ft deep assuming
a bedrock velocity of 18,000 fps.
An intermediate layer,similar to that beneath line 81-10,
wi th a veloci ty of 8,000 to 10,000 fps occurs under the
entire line.The highest velocities occur near the south
end of the line.The depth to this layer is 20 to 30 feet.
Thin surficial materials,which are probably partially
sa turated sands and gravels,have velocities of 3,000 to
3,500 fps.
4.12 Traverse 81-12
This traverse consists of two 1,000 ft spreads with seven
shotpoints.The line is about 4,000 ft downstream of traverse
81-11.The north end of the line crosses the river.
The interpreted profile for traverse 81-12 is shown in
Figure 9.No bedrock veloci ties were observed on this
traverse.Minimum depth calculations indicate that the
depth to bedrOck is probably greater than 300 feet,assum-
ing a bedrock velocity of 18,000 fps.
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4-9
An intermediate layer velocity of 6,700 to 8,000 fps occurs
under the entire profile.Velocities increase northwards.
Although they are somewhat lower than encountered on lines
81-10 and 81-11,they probably represent similar deposits.
Surficial materials 10 to 30 ft thick have velocities which
range from 4,500 fps at the south terminus to 3,500 fps at
the north terminus.
5.0 SUMMER 1981 SURVEYS
Traverses 81-13 through 81-19 were located on the north
side of the river,upstream from the proposed Watana Dam.
This area is underlain by a buried or II relict II channel.
Velocities of channel fill material vary considerably as
discussed in relation to the individual traverses below.
From borings discussed in the 1980 report (Woodward-Clyde
Consultants,1980),these materials are known to include
well consolidated glacial tills and outwash deposits,
younger alluvial deposits,and some lacustrine sediments,
all possibly frozen in part or entirely.Although the
seismic velocities of the channel fill referenced with each
traverse are a reflection of material properties,no
subsurface boring data was available in the vicinity of the
1981 traverses to identify the type of material that might
be represented by a particular velocity range.
Traverses 81-20 through 81-22 were run in areas of shallow
bedrock on the south abutment at Watana and on the south
abutment at Devil Canyon.For these as well as for the
other lines,higher velocity bedrock (ie 15,000 to 20,000
fps)is presumably more competent than lower velocity
bedrock (ie 10,000 to 14,000 fps).Specific rock types or
degrees of weathering,however,cannot generally be distin-
guished by velocity alone.Correlation of the seismic
veloci ties reported herein with the most recent surface
mapping and boring information may provide a better
idea of the extent of particular mapped units and struc-
tural features away f:r;-om their locations Known from out-
crops or cores.
5.1 Traverae 81-13
~hree 1,100 £t geophone spreads OVerlapped line 80-1 b¥50Q
ft and continued that traverse an additional ~,aoo ft to
5-2
the northeast as shown in Figure 1.The traverse crosses
undulating topography which rises gently to the northeast.
The interpreted profile of traverse 81-13 (Figure 10)shows
a continuation of the relict channel with a relatively
uniform depth toward the northeast end of the line where it
shallows.Bedrock,wi th seismic velocities ranging from
13,000 to 15,000 fps is from 200 to 250 ft deep beneath
most of the traverse.Channel fill material ranges from
6,000 to 8,000 fps and surficial sediments,which are
thicker toward the southwest end of the line where it
overlaps 80-1,average 2,200 fps.Several irregularities
in the time-distance plot (Figure B-1)appear to be due to
topographic effects.
5.2 Traverse 81-14
The southwest end of traverse 81-14 is located about 600 ft
from the northeast end of traverse 80-2.Three 1,100 ft
lines were used to extend traverse 80-2 to the northeast.
The northern end of the line turns north to the edge of a
small lake as shown in Figure 1.Relatively smooth topo-
graphy rises gently to the northeast to within 1,000 ft of
the small lake,then drops gently toward the lake.The
topography along the northern 1,000 ft was not surveyed;
the profile shown in Figure 11 for that area was approxi-
mated from small scale maps and field notes.
The interpretation of traverse 81-14 (Figure 11)shows
18,000 fps bedrock to be 500 ft deep beneath the southwest
end of the line.This requires a drop of about 200 ft from
the northeast end of line 80-2 which is not inconsistent
with the 1980 interpretation.The 500 ft depth places the
thalweg of the channel at an elevation of about 1,700 ft,
which is similar to that found on line 80-1 to the west and
somewhat deeper than on lines to the southeast.This
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5-3
deepening to the northwest is consistent with the interpre-
tation from other considerations that the ancient stream
flow was in that direction.
To the northeast,on traverse 81-14,bedrock shallows to a
depth of 100 ft,effectively the edge of the relict
channel,about 1,000 ft south of the lake.Along the
northern extension towards the lake,bedrock maintains a
depth of between 100 and 150 ft,and an average velocity of
15,000 fps.
Two layers of channel fill are apparent on the profile.
Material with a velocity ranging from 9,000 to 10,500 fps
as thick as 400 ft occupies the bottom of the relict
channel and is overlain by a 50 to 150 ft thick 6,000 fps
layer that continues to the north beyond the limits of the
relict channel.The veloci ty of the deeper layer is
similar to that interpreted as possible permafrost else-
where in the area.If it is indeed frozen,then it may be
underlain by less dense,unfrozen sediments and the depth
to bedrock may be as much as 100 ft shallower than shown in
Figure 11.This is assuming that only the upper 100 ft is
frozen and that the velocity of the underlying material is
about 7000 fps.
Velocities of surficial deposits range from 1,200 to 1,800
fps beneath traverse 81-14 and vary from 20 to 30 ft in
thickness.
5.3 Traverse 81~15
The center portion of traverse 81-15 consisted of two
550 ft geophone spreads across the apparent topographic
expression of the Fins structure near the top of the v~lley
wall on the north side of the l:"iver.Topography across
this central portion is somewhat irregular d~e,presumqbly,
5-4
to the underlying structure.Slopes to either side of this
central portion were too steep for continuation of the
line.Therefore,two extensions were run off the east and
west ends of the central traverse but shifted about 200 ft
further upslope to an area of more subdued topography
(Figure 1).
Data from traverse 81-15 indicates no intermediate layer
( 7 ,000 fps)such as found on nearby line SW-3.Instead,
the most reasonable interpretation (Figure 12)of the data
shows relatively low velocity bedrock (11,000 to 12,700
fps)underlying relatively thin surficial materials with
velocities of 1,000 to possibly as much as 4,000 fps.
A bedrock velocity change at the southwest end of the
extension to 16,000 fps may indicate the downstream boun-
dary of the shear zone.
All apparently anomalous arrival times (Figure B-3)can
be explained by topographic effects or by slight thickness
changes in surficial materials.Two possible locations of
resistant ridges in bedrock within the zone are beneath the
northeast end of the extension where arrivals are consider-
ably more irregular than elsewhere.No such irregularities
occur along the central portion of the line.
5.4 Traverse 81-16
This traverse consisted of two 1,100 ft geophone spreads
across a deep section of the relict channel adjacent to
the Susitna River slopes upstream from the proposed dam
site.Topography in this area is gently rolling and fairly
level.The east end of traverse 81-16 is within 100 ft of
the south end of traverse 80-7.
The interpretive profile of traverse 81-16 (Figure 12)
shows the depth to bedrock to vary between 200 ft at the
5-5
west end and 450 ft at the east end of the line.Bedrock
velocity is 18,000 to 19,000 fps.Channel fill ranges from
5,500 to 10,000 fps and thin surficial materials,1,300 to
1,800 fps.The 5500 fps materials appears to be a younger
filled channel.The shape of this channel,however,is not
well defined.
Bedrock elevation near the east end of the line is about
1,775 feet.This appears to be about the deepest part of
the channel in the area .The elevation agrees with that
noted on SW-3 to the north.
5.5 Traverse 81-17
A single 1,100 ft geophone spread was run northerly from
the east end of traverse 81-16.The line is about 300 ft
east and parallel with traverse 80-7.The configuration
and velocities shown on the interpretive profile (Figure
13)agree with those interpr~ted for traverse 80-7.
Bedrock with a probable maximum velocity of 20,000 fps
shallows from 400 ft at the south end,near the east end of
line 81-16,to about 200 ft at th~north end.Channel fill
material averages about 8,000 fps and surficial materials
about 1,800 fps.
5.6 Traverse 81~18
This traverse consisted of a,single 1,100 ft line which was
run in conjunction with line 81-19 across the southern edge
of Borrow Area D north of Quarry SOUrce B.A prominent
gully separated the two lines and precluded their being run
as a single traverse.The topography along traverse 81~18
is relatively flat,sloping gently to the east.
The profile of line 81 ....18 shown in Figure 13,indicates
20,000 fps bedrock at a fairly uniform depth of 325 feet.
5-6
Bedrock depth at the eastern end of the line is based on
depths interpreted for line 81-19.Intermediate velocity
material is predominently 6,500 fps with a wedge of 8,000
fps material,below the eastern end of the line which is
consi stent wi th travers e 81-19.Surf icial rna terials
ranging from 1,200 to 2,000 fps thin toward the east from a
maximum thickness of 60 ft near the west end.
5.7 Traverse 81-19
This traverse consisted of two 1,100 ft geophone spreads
extending easterly from about 600 ft east of traverse
81-18.The traverse crosses line 80-8 near the midpoint.
The line was approximately parallel to contours sloping
gently toward the west.The slope is very steep toward the
south.
The interpretive profile of line 81-19 (Figure 14)shows an
irregular bedrock surface ranging from 300 to 450 ft deep.
The deepest portion is near elevation 1700 which is the
lowest noted during this survey.Bedrock velocity ranges
from 13,000 to 16,000 fps.
Two layers of intermediate velocity materials are apparent.
They consist of a 6,000 fps layer 80 to 150 ft thick
overlying a 7,500 to 8,000 fps layer.Although thicknesses
vary somewhat,this is consistent with the interpretation
for line 80-8 where the lines cross.Surficial deposits
are up to 40 ft thick with velocities from 1,200 to 2,500
fps.
5.8 Traverse 81-20
This traverse extends line SW-l on the south abutment of
the proposed Watana Dam.Total extension was about 1000 ft
to the east.The traverse consisted of overlapping 550 and
300 ft geophone spreads wi th two 225 ft spreads over the
r
!
r-
i
5 ...7
east side of the traverse to produce more detailed data in
that area.Gently rolling topography along the traverse
rises slightly toward the east.
Figure 15 shows that bedrock,interpreted to be about
18,000 fps,underlies the entire traverse at shallow depth,
generally less than 10 ft.A small wedge,up to 50 ft
thick,of intermediate velocity material,averaging
7,000 fps overlies bedrock near the east end of the line.
This material was identified as varved silts and clays in
boring DH-25 (U.S.Army Corps of Engineers,1979).
5.9 Traverse 81-21
Four overlapping 550 ft geophone spreads and several 225 ft
detail spreads were run across the suspected projection
of the Fingerbuster structural feature on the south
abutment of the proposed Watana Dam.The total length of
the line was about 1900 ft.It crosses line 81-20 near its
northeastern end.The topography rises steeply to the
southwest along the traverse.
The purpose of traverse 81-21 was to delineate,if possi-
ble,the Fingerbuster zone in order to locate a drill site
for further exploration of the zone.As shown on the
interpretive profile of the traverse (Figure 15),the
structural zone appears to occur as an area of 12,000 fps
bedrock flanked by more competent 18,000 fps bedrock.This
is overlain by 1,500 to 3;500 fps surficial materials which
range in thickness from zero to 40 feet.
The location of the zone was thought to be khown more
preHjisely from appa.rerit anomalies on field time dista.hce
plots ~Several anomalies apparent on the time ....distance
plot (Figure 8 ....6),cati be attributed for the most part to
tbpeg~aphi6 irregula.rities ahd to changes in thickness of
5-8
the near surface layer.The zone appears to be delineated
by a prominent slope break to the west and a rapid thinning
of surficial deposits to the east.It appears that a
topographic low exists over the central portion of the
zone.The depression appears to be due to erosion by a
crossing stream.
5.10 Traverse 81-22
This traverse was run as three overlapping 550 ft geophone
spreads along the ridge on the south abutment of the
proposed Devil Canyon Dam.The eastern portion of the
traverse crosses the southern ends of lines 80-12 and
80-13.The somewhat irregular ground surface along the
traverse slopes downward toward the east end.
The interpretive profile of traverse 81-22,shown in Figure
16,shows very shallow bedrock ranging from 11,000 to
15,000 fps overlain by surficial materials of 1,800 to
2,000 fps.The surficial material appears to average
about 10 ft thick but thickens to as much as 30 ft at one
location near the east end.Intermediate layers of 5,000
and 10,000 fps interpreted for the south ends of 80-12 and
80-13 were not apparent from the data for 81-22.
6.0 FALL TRAVERSES-FOG LAKES AREA
The Fog Lakes traverse consisted of 48-500 ft geophone
spreads with common end shot points.The location of
the traverse was selected to cross areas of possible
buried channels which could contribute to seepage from the
reservoir.Topography along the line is gently rolling and
relatively flat locally.Elevations range from less than
2,300 ft across the Fog Lakes valley,approximately fi ve
miles east of the proposed Watana Dam,to about 2,400 ft
near the proposed south abutment.
The interpretation of the data for the traverse,shown in
Figures 17 through 23,indicates that apparent bedrock
velocities vary substantially along the traverse,from
20,000 fps to as low as 10,000 fps.
Two types of intermediate material are apparent.The
first ranges from 4,500 to 7,000 fps and is interpreted
to consist of poorly consolidated,saturated glacial
deposits.The second ranges from 8,000 fps to as much as
10,500 fps.This is suspected to be well consolidated
glacial sediments in part or entirely frozen.Surf icial
deposits range from 1,000 to 3,000 fps,are as thick as 50
ft in some areas,and are absent in others.
Several areas along the traverse appear to be underlain by
buried channels which extend below the proposed reservoir
level.The two most prominent of these are near the west
end of the traverse (Figure 17)and beneath the Fog Lakes
Valley (FigUres 22 and 23).Near the west end,a channel
which may be as deep as 300 ft (to elevation 2,030)is
filled fuainly with low velocity (4~60 to 6000 fps)de~
posits;,Higher velocity ChOintlel fill (9000 ips)is indi ....
cated near the east side of the channel bUt the contact
6-2
between the two types of channel fill is uncertain.It is
possible that the higher velocity material is permafrost,
in which case unfrozen sediments (with lower velocities)
could be present below it and the total depth of the
channel could be somewhat less than shown on the profile.
The width of the deepest part of the channel appears to be
about 1,000 feet.
The apparent channel in the Fog Lakes Valley is more than a
mile wide.The deepest part appears to underlie the lowest
part of the valley at an elevation of about 1,940,350 ft
be low ground surface.Much of the rest of the channel,
which extends below the topographic high northwest of the
valley,is below an elevation of 2,100 feet.
The shape of the channel shown on the profile is based
on marginal arrival-time data from distant offsets and
from minimum depth calculations where distant offsets did
not penetrate sufficiently to detect rock.The shape,
therefore,could be significantly different,especially
on the west side where depths could be greater.The
interpretation shown,however,is considered to be a
reasonable estimate of the maximum depth within the limits
of the uncertainties of the data.
The most critical uncertainty is the nature of the 8,000
to 11,000 fps apparent channel fill material.If this
material is interpreted to be well consolidated glacial
deposits then the interpreted profile as shown in Figures
22 and 23 is appropriate.However,if the material is
frozen,then lower velocity material could underlie the perma-
frost and depths to bedrock could be shallower than shown
on the Figures.
-
6-3
A third possibility,which is not likely,is that the
apparent channel fill could instead be weathered bedrock,
at least in part.If this were true the bedrock velocity
would be so close to that expected for frozen or well
consolidated sediments that the contact between them could
not be distinguished.It is remotely possible that the
apparent indications of high velocity bedrock at depth
are the result of irregularities in shallower,very low-velocity weathered rock or from steeply dipping contacts
between weathered bedrock and high velocity channel fill.
!""'"
i
!
r
i
l
-
-
An attempt was made to resolve the nature of high velocity
apparent channel fill material using shallow reflection at
the location of refraction line 81-FL-3.Results were
not definitive but the most likely reflection appears
to place the bedrock contact at a depth of 170 ft below
ground surface which is similar to the depth indicated by
refraction in that area.This depth,however,indicates an
anomalous high near the middle of the broad channel which
makes the interpretation even more tenuous.
Other areas of apparent channeling are present along the
central portion of the traverse.These channels,although
broad in some cases,are all above elevation 2,150 and
generally shallower than elevation 2,200.
At several locations along the Fog Lakes Traverse,bedrock
lows appear to coincide with higher seismic velocities
which is contrary to conditions elsewhere in the vicinity.
No explanation for this is evident from the present data.
.....
-i
.....
r-
!
.....
r
7.0 MAGNETOMETER SURVEYS
Approximately 3,000 ft of magnetometer surveys were run as
two long traverses and three shorter traverses in an
attempt to locate buried mafic dikes on the south abutment
of the proposed Devil Canyon Dam.One of the long tra-
verses was run along the alignment of refraction line
81-22 .
No significant anomalies were detected which could not be
attributed to cultural features or to topography.The
method was found to be not applicable for mapping the dikes
and therefore the program was discontinued after these
trials .
-
r
-
.....
8.0 GENERAL OBSERVATIONS AND CONCLUSIONS
In general,results of the 1981 seismic refraction surveys
are in good agreement with surveys interpreted during 1980
and in previous years.Only a few cases were found where
independent interpretations did not agree.The most
notable of these were the lack of intermediate velocity
material indicated on lines 81-15 and 81-22 which crossed
or were near to existing lines for which shallow,interme-
diate velocity material had been interpreted.This
difference may be a simple result of differing interpreta-
tion procedures or possibly an indication of rapid lateral
changes.Boreholes,or possible additional,more detailed
seismic lines,are needed to resolve these differences.
As previously discussed,the seismic refraction method
is subject to a number of limitations which affect the
confidence one can place on the details of interpretations
based soley on refraction data.For example,a great deal
of uncertainty exists as to the nature of the apparent
channel-fill material along the Fog Lakes traverse.A few
borings in the interpreted channel areas,however,should
resolve these uncertainties and provide a basis for further
evaluation of possible seepage problems during design
studies.
The interpretation of material types represented by various
velocities have been discussed in previous reports and are
covered only in general terms herein.The present profiles
were developed assuming the material types and velocities
encountered in this survey were simi lar to those encoun-
tered in previous surveys which were based,in part,on
boring information.
-
-
-
-
REFERENCES
Dames and Moore,1975,Subsurface exploration,proposed
Watana Dam site on the Susitna River,Alaska:Report
for Department of the Army,Alaska District,Corps of
Engineers,Contract DACW85-C-0004,12 p.
Redpath,B.B.,1973,Seismic refraction exploration for
engineering site investigations:U.S.Army Engineer
Waterways Experiment Station,Explosive Excavation
Research Laboratory,Livermore,California,Technical
Report E-73-4,55 p.
Shannon and Wilson,Inc.,1978,Seismic refraction survey,
Susitna Hydroelectric Project,Watana Dam Site:
Report for Department of the Army,Alaska District,
Corps of Engineers,Contract DACW85-78-C-0027,17 p.
U.S.Army Corps of Engineers -Alaska District,1979,
Southcentral Rai lbel t Area,Alaska Upper Su si tna
River Basin Supplemental Feasibility Report:
Appendix Part I.
Woodward-Clyde Consultants,1980,Final Report,Susitna
Hydroelectric Project Seismic Refraction Survey,
Summer,1980:Report for R &M Consultants,22 p.
TABLE 1
1980-1981 Seismic Refraction Li
Line
WCC R &M Location Profile Time-Distance Length
Line No.Survey No.Figure Figure Plot Figure (ft)
80-1 80-1 2 **6,600
80-2 80-2 2 **5,500
80-3 80-3 2 **2,000
80-4
80-5
80-6 80-6 2 **1,100
80-7 80-7 2 **2,200
80-8 80-8 2 **2,200
80-9 80-9 1 **1,100
80-10
80-11 80-11 2 **2,200
80-12 80-12 3 **1,120
80-13 80-13 3 **1,120
80-14
80-15 80-15 3 **440
81-1 81-1 2 4 A-I 1,000
81 ....~81-2 2 4 A-I 2,000
81-3 81-3 2 5 A-I 500
~...;-;;-""
,101lo#-"
81-4 81-4 -2 5 A...J..900
*Profiles and time-distance plots included in previous report (Woodward-Clyde Co
Data
Number of
~gments/Shots
8/31
5/19
4/11
2/5
2/10
2/10
1/3
4/13
3/8
3/8
1/2
1/3
2/6'c
1/2
1/3
lltants,1980).
Comments
Watana Rt Abutment-Relict Channel--Extended
NE by 81-13
Watana Rt Abutment-Relict Channel--Extended
NE by 81-14
Watana Rt &Lft Abutments Upstream--81-6 Crosses
River in Middle
Not Used
Not Used
Watana RT Abutment--Relict Channel Area
Watana RT Abutment--Relict Channel Area
Watana Quarry Source B--Extends SW-5 to South
Watana Borrow Area E--Extends SW-14 to NW
Not Used
Watana Borrow Area E--Adjacent to Tsusena Creek
Devil Canyon Saddle Dam Area--Left Abutment
Devil Canyon Saddle Dam Area--Left Abutment
Not Used
Devil Canyon Saddle Dam Area--Left Abutment
Run Over River Ice,2.1 Miles Upstream from
Proposed Watana Dam Centerline.
R~Over River Ice,1.6 Miles Upstream f~om
Proposed Watana Dam Centerline.
Run Over River Ice,1.1 Miles Upstream from
Proposed Watana Dam Centerr'ine.
Run Over River Ice,0.6 Miles Upstream from
Proposed Watana Dam Centerline.
TABLE 1 (Continued)
Line
WCC R &M Location Profile Time-Distance Length
Line No.Survey No.Figure Figure Plot Figure (ft)S
81-5 81-5 2 5 A-I 450
81-6 81-6 2 6 A-I 450
81-7 81-7 1 6 A-2 3,200
81-8 81-8 1 7 A-2 2,500
81-9 81-9 1 7 A-2 2,000
81-10 81-10 1 8 A-3 2,100
81-11 81-11 1 8 A-3 2,800
81-12 81-12 1 9 A-3 2,000
81-13 80-lX 2 10 B-1 3,200
81-14 80-2X 2 11 B-2 3,300
81-15 &15X BH-ll 2 12 B-3 2,100
81-16 16-81 2 12 B-3 2,200
81-17 2 13 B-4 1,100
"-81-18 QSB 2 13 •B-4 2,200
81-19 QSB 2 14 B-5 1,100
4-....~'
81-20 Svl-IX 2 15 B-6 ","1,600
81-21 .BH-12 2 15 B-6 1,850
81-22 17 3 16 B-6 1,500
81-FL-l
to Fog Lakes 1 &2 17 -23 Cl -C7 28,800
81-FL-48
Number of
~gments/Shots
1/3
1/2
3/9
3/6
2/6
2/6
3/9
2/7
3/10
3/5
4/11
2/8
1/5
2/10'
1/6
,'..,
5/11
5/19
3/6
48/138
Comments
Run Over River Ice,0.5 Miles Upstream from
Proposed Watana Dam Centerline.
Run Over River Ice,0.1 Miles Upstream from
Proposed Watana Dam Centerline.
Run Over River Ice,4.0 Miles Downstream from
Proposed Watana Dam Centerline.
Run Over River Ice,5.2 Miles Downstream from
Proposed Watana Dam Centerline.
Run Over River Ice,7.3 Miles Downstream from
Proposed Watana Dam Centerline.
Run Over River Ice,8.2 Miles Downstream from
Proposed Watana Dam Centerline.
Run Over River Ice,9.3 Miles Downstream from
Proposed Watana Dam Centerline.
Run Over River Ice,10.1 Miles Downstream from
Proposed Watana Dam Centerline.
Watana Relict Channel Area--Extends 80-1 to NE
Watana Relict Channel Area--Extends 80-2 to NE--
North Extension Not Surveyed
Watana Rt Abutment--Fins Area
Watana Relict Channel Area
Watana Relict Channel Area--Not Surveyed
Watana Relict Channel Area--N of Quarry
Source B
Watana Relict Channel Area--N of Quarry
~/
Source B
Watana Left Abutment--Extends SW-l East
Watana Left Abutment--Crosses 81-20
Devil Canyon Left Abutment--Crosses 80-12
and 80-13
Watana Fog Lakes Area--Continuous Profile
i
w
DR-13\\/~:<.
\C J )r '-S ··~·i '~\
r"(7 Ii ~l~-,_(r'WATANA )jJ I
/...~LOCATION OF DETAIL AREA'c>---.SEISMIC REFRACTIO
)/..
~.,.,.'DR-27 8
45 46 47 48
§~g
'"Ie
w
I'-
q-
W
I'-
W
':',.
o
1
FOG LAKES TRAVERSE
,:;-=~.l..-3_,5 36 37.38 39
-,
N 3,234.000'-
N 3,?&l.ooo
N 3.232.000
N 3.226,000
~3.224,000
PREPARED BY.WOODWARD -CL YDE CONSULTANTS
8.o
;!:
w
2.300
))
AREA
FRACTION LINES
4 8 MILESSCALE:O~~lIIIIIi;iiiiiiiiii __!I~
\500 ----------
1600-
~
\100 ~-
\'600,--../'
~
-N-
~
1000 2.000 FEETSCALE:~~~~~iiiiiii_!
NOTES !100 FEET
I LOCATION ACCURATE TO OF DIRECTIJN NOT SHOWN
;.MINOR MID -LINE CHANGES
FIGURE I
~
-N-
1
0 2 3
I I I I
SCALE IN MILES
/
WATANA DETAIL AREA
(Figure 1 )
12
-~----:-&.-_-~.-""'t___-33 34 41 42---_-"~---23 -e-=28 29 48
Fog Lakes Refraction Traverse
Lines 81-FL-1 to 81-FL-48
__~..-----r-----
FLOW
...-------
_.
P.
/
/
/
/
/
/
/
/
/
/
/
t1
I
I
DM-B
WATANA DAM
-..
...~..-.'
I
WATANA ,
APPROXIMATE LO(
LINES OUTS
PREPARED BY WQODWARD -CLYDe:CONSULTANTS
FIGURE 2
...~...~
\
"."'~
FOG ···~~.EEK
/
-V'"
ICINITY MAP-
:ATION OF REFRACTION
DE DETAIL AREA
-\
\
o
I
200 400
I I
SCALE IN FEET
600
I
1450
SW-16
sw 15 -
PREPARED BY WOODWARD -CLYDE CONSULTANTS
1400 -
(
1300~
---1-2~OO~
----1000~
~
800
................
SUSITNA RIVER
...~
LOCATION OF
SEISMIC REFR
,1450
...~.~."~~.....~.
~::::::~.~~DEVIL C~NYON ~'-
REFRACTION LINES
=:.
FIGURE 3
1600
South .......
81-2
.....
Q)
Q).....
1500 ~--------------------------------
8000co.....
(lJ>Q)
w 1400
1300
1600
_7----_0-.-.-1/
/.
O/
,./
S35E ~
81-1
?_-O--?---
7000
?-----.-?
16000 -18000
1600
co.....
~
Q)
LU
1500
1400
1300
4600
--
1500
1400
1300
SEISMIC REFRACTION PROFILES
81-1 AND 81-2
lD -CLYDE CONSULTANTS
"'--.-?
-18000
)00
5000 "
""/
"/
0/
---?-~......
1600
1500
1400
1300
iOO
~OO
:00
~ILES
Compressional wave velocities in feet per second
Horizontal Scale:1 inch =200 feet
Vertical Scale:inch =100 feet
FIGURE 4
1500
South~
81-3 1500
6
+-'1450 5000 1450ClJ
ClJ
'+-
c'.........O _0/
a -1-?--
+-'
,,"M'inimum
Cll>~
UJ Assumed 17000 Depth
1400 1400
1350
1500
+-'1450ClJ
ClJ'+-
"ca
+-'ro>,
ClJ
UJ
1400
1350
S5E~
-----6500 "..................
./'--0-......-
-?--0--?-
-'
1350
81-4
----------
14000
Minimum
Depth ---....._ 7 - '-.
Assumed 17000
SEISMIC REFRACTION PRI
81-3,81-4 AND 81-f
PREPARED BY WOODWARD -CLYDE CONSULTANTS
1500 -
1450 -
1400 -
1350 -
S75E ---..
81-5
5000 - - - -
-0--
12000
7---0 --_7
Minimum /
Depth:/Assumed 17000
c-1500
Crosses 81-4-
------
?--0-7
10
r-1500
f-1450
f-1400
'-1350
Crosses 81-5-Compressional wave velocities in feet per second
10
Assumed 6000--------0-
~-?--
ILES
1-1450
-.
f-1400
'-1350
Horizontal Scale:
Vertical Scale:
1 inch =100 feet
inch =50 feet
FIGURE 5
15000co.....ro
~
W
1450
1300
1150
South --....
81-7
5000_0--°-_---?-_--O0,/--_.....--__- --O-"...........,/---0-
S8E -+--
1500 81-6 1500
.....1450 /1450
Q)Assumed 6000Q)/'+-,
/c 'O0 7_°-""'';:;
---;>ro .---.>\M"~
w '~1400 -Inlmum ,1400Assumed18000Depth
Horizontal Scale:1 inch =100 feet
-"";-:...->w...
1350 Vertical Scale:1 inch =50 feet 1350 --
SEISMIC REFRACTION PROFILES
81-6AND81-7
IWARD-CLYDE CONSULTANTS
FILES
1450
0-0.......,--".........--"""0__0-----.1300-
19000
1150
Horizontal Scale:1 inch '=300 feet
Vertical Scale:inch '=150 feet
1000
Compressional wave velocities in feet per second
-
FIGURE 6
East~
1500 81-8
t)1400
~
1300
4800
-0-----0--.--.....,....<:.:,/
'0 ~-------------------.....---15000
1200
S55E~
81-9
3000 _----0--0------__
----0----0 ---------
18000
7500
-7·-0.........
"-"................
---0 --0---_-------------0---
1500
1200
+-'1400
Q)
Q).......
c
.Q
+-'
Ctl>Q)
w 1300
"-"
SEISMIC REFRACTION PFi
81-8 AND 81-9
PREPARED BY WOODWARD -CLYDE CONSULTANTS
1500
1400
3800 0/
./-------../-~----------------
1300
18000
1200
1500
Compressional wave velocities in feet per second
1400
3500-0-------------0--
6500
-Ii·':'.•
:"ILES
1300
1200
Horizontal Scale:1 inch =200 feet
Vertical Scale:1 inch =100 feet
FIGURE 7
co
'';:::;
ttl>Q)
UJ
1400
1300
1200
1100
1500
1400
S23E ---...
81-10
4000
___-0---0--- - - - ----0--0 ------0------
8300
Greater than 300 feet deep assl
S17W~
81-11
1300
1100
1200
30--- - - --0---0------- -------0-------0·--
8000
Horizonta
Vertical ~
1000 J Approximately 400 feet deep assuming 18000 bedrock
SEISMIC REFRACTION PROF
81-10 AND 81-11
'REPARED BY WOODWARD CLYDE CONSULTANTS
1400
___0
----_--------0--0------
1300
9500
Horizontal Scale:1 inch =200 feet 1200
ming 18000 bedrock
Vertical Scale:
1500
inch =100 feet
1100
Compressional wave velocities in feet per second
10000
Scale:1 inch =300 feet
cale:inch =150 feet
ILES
1300
-1200
1000
FIGURE 8
1300
South~
81-12
1400 L ----::::::---------
-?-0--0 __2.500
----0-0----------
co
+"ro
6)
W 1200
:1100
-
8000
Greater than 300 feet deep assuming 18000 bedrock
SEISMIC REFRACTION PROF
PREPARED BY WOODWARD -CLYDE CONSULTANTS
-4500 __?---
-0--&-_---
6700
ILE 81-12
1400
1300
1200
1100
Compressional wave velocities in feet per second
Horizontal Scale:1 inch =200 feet
Vertical Scale:inch =100 feet
FIGURE 9
--
--------
N35E--
81-13
2500
2000,,------ - - -
",.
----------------
7000
-----l
I
I
I
I
---.;'
",---........-.......
/'
----
13000
Overlaps
80-1C
2200
2100
f-
LlJ
LlJu..
z·
0
i=2000
<t:.....r .'"...
>LlJ
....J
LlJ
Dotted lines from
1980 interpretation
1900
.
...................-
1800
1900
2300 I N35E-2300
I LlJ
Z
::::i
r~-----....2500-------.......--22002200•.",.f-,/f-LlJ
LlJ ,/LlJ
LlJ"u..-,/u..
z 2000 ..,/z00f-f-<t:>6000 2100 <t:
LlJ ~..>
-<j:--,....J "LlJ
LlJ ./....J
,/LlJ
/
,.",
2000 ,.",.2000---'-----8000 --15000-
PREPARED BY WOODWARD -CLYDE CONSULTANTS
,,---.,."..........
/-_/
12200
__2000,.,
"6000~'~2100
8000
.--------
13000
-
•
l.U
Zn2000
~1
-1900
Compressional velocities in feet per second
o 100 200'
f---1 I I
HORIZONTAL SCALE
IN FEET
~...
SEISMIC REFRACTION PROFILE
LINE 81-13 (80-IX)
FIGURE 10
2300 N47E-81-14
1570
1200
---
2300 r NORTH-.---.
F-.......·----
I------_--ww
~2200k-_
~I ~--------
u
2100 r~
10500
---------- --"---------
1200 __--------
18000
9000
--~-
,;'
6000 "
./
./
;/
;/
..""
-
LI NE 80-2 600 ft.
1700
1800
2200
2100
I-
LU
LUu...
Z
0 2000
I-«>LU
..J
LU
1900
SEISMIC REFRACTION
LINE 81-1 {80 -2
PREPARED BY WOODWARD-CLYDE CONSULTANTS
N80E-
81-16
2200 13001-_;--__------'
2100
\-
u.J
u.J
U.
Z
0 2000
\-"-et>""u.J
...J
u.J
1900
1800
,
",
'\
'\
"10000 "
""
2200
N50E-
-
11000
12700
-......
//"'----~~-
/
..---;I"--
81-1581-15X(SW)
11500
"-,1500.-.....,""--
16000 ?~_1000
:-~I
?
I,zo
\-et>
u.J
...J
W 2000
\-lli 2100
LL-;'·-';;···
1900
SEISMIC REFRACTION P
LINES 81-15,15X AND:
PREPARED BY WOODWARD -CLYDE CONSULTANTS
-----2200
5500
"-"""'".........
"-~------/'-~
/'---/'18000
/'
2100
I-
UJ
UJ
U.
Z
0
2000 I-
<{
>UJ
--l
UJ
/'
7/1900",.
~
7 ,.,.----.9000----1800--........
2200
81-15X(NE)
a 100 200
..-E""3 I I
HORIZONTAL SCALE
IN FEET
Compressional velocities in feet per secondI-
UJ
UJ
U.
2100 6
I-
<{
->
UJ
--l
UJ
2000
?
120007?
1100 __-
- ? - --------~-J;.-~
I~o
I~
I~
:>ROFILE
81-16 1900
FIGURE 12
2400 NORTH-81-17 2400 2200 N73E-
2000
2300 2300 2100 ---
2000 ----.---1800 -----•-----2200 1500 -2200 2000-----I-
UJ
UJ 7600u..
z
0
I-2100 8200 2100 1900<!/>UJ
-I
UJ
/
/'----~...
2000 /'2000 1800
/~
/'
/'20000
1900 /1900 1700
--
1800 1800 1600
~;-.:.,~"
SEISMIC REFRACTION PROFILE
LINES 81-17 AND 81-18
WOODWARD -CLYDE CONSULTANTS
N73E-81-18 2200
2000
------------
LINE 81-19
600 ft.to East
--.---........---o
2100
6500
•----~------20000 --____----
-
---
2000
I-
UJ
UJ
LL
Z
0
1900 I-«>UJ
...J
UJ
1800
1700
1600
_0 100 200
I---l I I
HORIZONTAL SCALE
IN FEET
Compressional velocities in feet per second
'-J PROFILE
)81-18
FIGURE 13
2300 N78E-81-19
LINE 81-18
600 ft.to West
Crosses
LINE 80-8
2200
---
-----
-------------------
.
6000
2000
2100
8000
1900
1800
1700 '-
8000 --,.-
/'
/
/
./
~/16000--
"ii-:-.
1600
SEISMIC REFRACTION PROFILE
LINE 81-19 (QSB)
ODWARD CLYDE CONSULTANTS
---~-
2300
rosses
~E 80-8
JL-------..:--
2
-
o
-
oo
-----------.~_::-::-=::=12200---------
6000 7---_.2100~-,1
---2000
7500
1900
1800
--1700
Compress.ienal velocites in feet per second
o 100 200
F"l I I
HORIZONTAL SCALE
IN FEET
PROFILE
3)
FIGURE 14
EAST-
81-20
2100
?
C
LIN
--:::=:-=::------'::"':-- - -
7000 ~.....?",
"""'----------".
Crosses
LINE 81-21
I
-------
f-
LlJ
LlJ
LL.
z2 2000
f-«>LlJ
...J
LlJ
1900 18000
18000
N45E-
18000
/'
/
/
/,
/"
/
81-21
12000
~
',1500
....................
.......,
".....?
................3000........
""----
?
\
\
\
\
-
18000
2300 __---.,---..........
1900
2100
2200
zo
f-«2000>LlJ
...J
LlJ
f-
LlJ
LlJ
LL.
1800
SEISMIC REFRACTION PROFILES
LINES 81-20 (SW-IX)AND
81-21 (BH-12)
:JODWARD -CLYDE CONSULTANTS
Crosses
LINE 81-23
?
.,/......-
)0
2100
I-w
W
LL
z
2000 2
1-«>w
...J
W
1900
2200
-.;...'.
:>ROFILES
X)AND
2100
I-w
W
LL
Z
0
2000 i=«>w
...J
W
1900
1800
Compressional velocities in feet per second
o 100 200
H I I
HORIZONTAL SCALE
IN FEET
FIGURE 15
Crosses
Line SW-17 EAST-81-22
11000
15000
Crosses Crosses
Line 80-12 Line 80-13
......._---,!!
""_-'_--.1180iO:;;O~-_--",,--_--_-'-_-""---.-"'~~
1500
I-
LlJ
LlJ
LL.1400
z
0
i=«>
LlJ
..J
UJ
1300
1200
"'l -
~,.
FOG LAKES SEISMIC REFRACTION PROFILI
LINE 81-22 (RaM 81-17)
ODWARD -CLYDE CONSULTANTS
81-22
1500
f-w
'00 1400 w
L.L
Z
0
f-
<.(
>
11000 w
-J
w
1300
1200
-
ON PROFILES
17)
.
Compressional velocities in feet per second
o 100 200
Eii"l I I
HORIZONTAL SCALE
IN FEET
FIGURE 16
81-FL-48 81-FL-47 81-FL-46
4300
..........--.........
..........
"-
\
"...
5000
13700
LU
(f)
a::
LU 14700>(f)z
<!a::
I-
u..
0
0
Z
LU
l-
t/)
LU
S
2300
2200
2100
f:~~~==~~(:~0~3~)=~S~7~7E~=~O~~J§i;:::=-:=:-:=:=-=~~~~~J~~_2400 2500
-- -2000 (99 4 )-__3000
-_".---1500--0-_ _1800-.--.....--------
.
)
81-F L-44
S77E-
(906)
81-FL-43
1100
2300 r-
______12~~~~--,_1620 2300
zo
I-
<!>
LU
-l
LU
I-
LU
LUu..
-2200
co
LU
Z
-l
I
U
I-
~-2100
5000
18000
----------_.......,.;
4200
9000
LU
Z
-l
-7-."~----7-)/'
......7-/
/-/
I
/
/
/
/
/"
""..-"
I
-.i..~
2100 -~
2200 r--"<t:
2000 r--2000
FOG LAKES SE ISMIC REFRACTION PROF
SHEET 1 OF 7
OODWARD -CL'l'DE CONSULTANTS
81-FL-46 81-FL-45
2400
:-~:__:-:~:__:-=:-:-~i"3c}o~~::-~('::90~,5~)J
- -__13~0 1300------....-2000 2300
4300
'""-
\
\.
"'-"-
5200
<I:
UJ
Z
....J
I
U
f-
<I:
:2:
------....--15000 .-'
2200
2100
2000
f-
UJ
UJ
U.
zo
f-
<I:>UJ
....J
UJ
-,,'--
:TION PROFILES
-Compressional wave velocities in feet per second
Numbers in parentheses above topographic
profile refer to survey points
o 100 200
1-=-1 I I
HORIZONTAL SCALE
IN FEET
FIGURE 17
2400 I-
81-FL-42
S77E-
81-FL-41
~S88E-
(907)
I
I-2300 I-1800 2200.L 1800 _ - --~"'.--.....,_----~-----_2000 .'---
l.L - - - - - - - -2000 - _V4000- _ _6000
12500UJz
:::i
-'------------........---........
',6000 /................
'J '........"I 12500 ".......,I 12800 '\
........-_./
z·
o
I-«>
UJ
u:j 2200 I-co
I
U
I-«
i 2100 _:2:
81-FL-38 81-FL-37 81-FL-36
2400 I-S88E-1-1----S85E-
16000
13500
......18000
l_-----""-::::::----,w)-h~i(~90~,9:)~=-:==:-::=:::-:=:1~8~0~0-=1_1~.8~0~0~_==~=:-::-~.:-------2500 3000 _ - - -----,_.-----.----.......
//~23~0 ~7000 _".
~'!'".,/,~/'--zo
f=«u
~-.-..UJ
-l 2200 I-~
UJ -l
I
U
I-«
:2:
[
i
!
,
,
;
2100 I-
FOG LAKES SEISMIC REFRACTl
SHEET 2 OF 7
PREPARED BY WOODWARD -CLYDE CONSULTANTS
-40 81-F L-39
-2400
(908)--2500 ............5200-----....2300 I-......--------."'-UJ.,;'...UJ.,;'u../'"
/'z
057007000/'I-
/u <t:
/UJ >
Z UJ
/'::J-2200 ....J
14000 UJ
......./'I
"-"U
.",I-.......~.<t:......._-......::2:
-2100
2400
5000.,.,
-~_......
I-Compressional wave velocities in feet per second
0-2300 UJw -Numbers in parentheses abov,e topographicUJu..
profile refer to survey pointsz
....J Z
0
0 100 200II-U <t:I----l I II-
<t:>...-,""......UJ HOR IZONTAL SCALE::2:....J-2200 UJ IN FEET
-2100
ION PROFI L ES
FIGURE 18
81-F L-35
S85E-
81-F L-34
~N67E-
2500
5000
(912}
I
17000
~o
e .........-.............-.....
e----2800 ~---_e-
3000 _-----_e-I-2400
ww
LL
zo
I-«>~2300
w
14600 C-
ell
(9
oo
1.D
15200
2200
81-FL-31 81-FL-30 81-FL-2
N67E-
15500
15400
70005800
12500
w
w
Z
....J
I
U
I-«
::2:
-------------.-.....
I-w
W
LL
-,,'
z 23000
I-«>w
....J
UJ
2200
FOG LAKES SEISMIC REFRACTION PROFI
SHEET 3 OF 7
WOODWARD -CLYDE CONSULTANTS
81-FL-33 81-F L-32
-2500
(916)(915)
""'--I--2800
I 2400 I-
.::::::::-2800
w
."",-.--______2000 w
~-_--/---~.
LL
............Z
............7500 8500 0
"-.'"I-
15200 "8000 ./'«
./'>
"w
,,/w_2300 -J
~"..w w
........Z
"..---J-.---Iu
12000 I-«
2:
-2200
81-F L-29
(91 7 )
2800 -2400--...-----.
I-
15500 ww
LL
.-s;-~,LL Z
W -2300 0
z f=
-J «>
I w
U -J
I-w
«
2:
-2200
ON PROFILES
Compressional wave velocities in feet per second
Numbers in parentheses above topographic
profile refer to survey points
o 100 200
H I I
HOfUZONTAL SCALE
IN FEET
FIGURE 19
81-FL-28 81-FL-27
S80E-
I-
LU
LU 13,500LL
LL
Z LU02300r-~I-«....J
>I
LU U....J I-LU «
2:
2200 -
:::~GO -LSaO-.------
(918)
I
- -..2.§2~..,.._1_50_0 E2..0_1100--
14,000
(9
.."..
LU
Z
::::i
Iu
2200 r-~
2:
S80E-
3800 --
6500
---
-
...............-
81-FL-23
r-N83E -
(9t O)
5500-.------
81-FL-24
11,000
-......---2300...----
2400 I-
I-
~2300 l-
LL
zo
f=«>
LU
....J
LU
2100 -
FOG LAKES SEISMIC REFRACTI
SHEET 4 OF 7
PREPARED BY WOODWARD -CLYDE CONSULTANTS
81-F L-26 81-FL-25
(919)-2400
I
1800 1500 2100----.-__e_----------.-f--
UJ
UJ
LL
15,000 z
12,500 (,:J-2300 0
f--
UJ «
z >UJ:::i ...J
UJ
I
U
f--«
~-2200
81-FL-22
-2400
4000 1-7-.--,-"-
"....f--."..-2300 UJ",/'LJ.J
~LL
~...-I Z
UJ 0
14,600 z f--
:::i «>
I UJ
2200 ...Ju-UJf--«
~
Compressional wave velocities in feet per second
Numbers in parentheses above totographic
profile refer to survey points
o TOO 200
~I I
HORIZONTAL SCALE
IN FEET
ION PROFILES
-2100
FIGURE 20
8000
---
81-FL-19
2100
--1----
_e---2000
e
8000
(922)
81-F L-20
9000
(921 )
13,500
81-FL-21
N83E-
4500
2400 f-
:;;>'"--
5000 ....-__---
5000 //I-10-......__
~2300 f---__/
u.-----....~/
..........
'...../e--
~,//
"/"'--""15,000
zo
I-«>~J:
llJ 2200 ~llJ
Z
....J
J:
U
I-«
:2:
2100 t-
81-FL-17
N83E-
81-FL-16 81-F L-1
15,000
20,000
2400 ~--------:'::'::":'"""----+---::7------------lr----=::-:::::-=_I---_
2200 -3000 2600 /5000 5000 __-"_--_5500 __
-----~4500.-........--e------......~---.........../7----........../-~.'-.,."...,.~
7/---.I-2300
llJ
llJ
U.
2200 UJ
Z
....J
J:
U
f-«
:2:
2100
zo
I-«>llJ
...J
llJ
FOG LAKES SEISMIC REFRACTION PRl
SHEET 5 OF 7
lY WOODWARD -CLYDE CONSULTANTS
81-FL-19 81-FL-18
2200 1800-------.------
(923):-2400
2400___e __
8000 9700
I-
-2300 ~
LL---__1--7-----~-~---.
18,000 -
LlJ
Z
::::i
I
U
l-
e::(
~
-
zo
l-
e::(
>
LlJ
...J
2200 LlJ
2100
81-FL-15
I-
-2'300 ~
LL
.-'..
o 100 200'
H I I
HORIZONTAL SCALE
IN FEET
Numbers in parentheses above topographic
profile refer to survey points
Compressional wave velocities in feet per second
zo
l-
e::(
>
LlJ
...J
2200 LlJ
2400
-,
LlJ-
Z
...J
-"l-:._
15,000
............_2100-------_.---"'\6500
'\
\
\
\,
I
U
l-
e::(
~
-2100
"ION PROFILES
FIGURE 21
81-FL-14
N83E-
81-FL-13
(925)
2400 2000--
2000-------.-------1800.18qo
81-FL-l
1500--7000
-,
UJ
2300 z
...J
8700 11,500I10,500u9000f-«
~
f-
UJ
UJ
LL
zo
f-«>
UJ
Ld 2200
2100
\
"'-...----18,000 --"""-
?..........
"""----...?-!-----?------
20000
81-FL-2
2400
81-FL-3
(927)81-F L-l
8700
7000
-,
20,000?"
\
.,J
"
9500
Apparent Reflector
10,000
-
9500
~
UJ
Z
...J
I
U
f-«
~
2300
f-
UJ
UJ
LL
Z
0 ",..
f-2200«>
UJ
...J
UJ
--1i--.:.-,
2100
2000 (20,000)
18000
FOG LAKES SEISMIC REFRACTION PROFILE
SHEET 6 OF 7
DWARD -CLYDE CONSULTANTS
81-FL-l81-FL-12
1500----
7000
t-S63E -
(937 (926)
-_2000 1~- ---..1000~"50e;;- -4500
5000 /-...,/
\/'"/'"/'"-'",-/
2400
2300
I-w11,500
~wu...11,000 wz Z
..J 0
I l-
e:(u 2200 >l-
e:(W
..J:E w
2100
----?-----7--? -------.
2000
81-F L-4
(928):::,
-~5Q.L _3000 2300-------.--
Compressional wave velocities in feet per second
/'
,/
?,/
/',....,-.-
8000
..J
""I:l:!<
Z
..J
I
U
l-
e:(
:E
2200
2100
I-wwu...
zo
f=
e:(
>W
..J
W
Numbers in parentheses above topographic
profile refer to survey points ,
a 100 200
1--1 I I
1"fORIZONTAL SCALE
IN FEET
3000
ON PROFILES
-.
2000
FIGURE 22
r-S48E --2300 ~~0~-:------(~91?~9~)~J ~(9:~~0~)_~O.~
---__3800 2000 _----
--_1--'--
81-FL-5 81-F L.-6
3000_e--
81-F L-7
---
2200 I-8500
8500 8500
............
""----
.~
18,000
i...U
Z
....J
/--..,
.........
"-"""
I
U
~<t
2:
2000 I-
~
LlJ
LlJ
Ll.
zoi=2100 I-....J
<:(
>
LlJ
..J
W
23,000
1900 I-
81-F L-9 81-FL-10 81-FL-1
S48E-
17,000
9000
20,000
10,500
1
w
Z
....J
I-:r:
U
~<t
2;
l :::::--,""';:----1iiiiii~--,,~=::Z~~§"_:~-~;;;;;-~t...1~8~~2o=-==-:-:..!-!1!litC-:-9'"'"-1800 ~"3800 3000 1>--2300 -2000 1~c;;......- _...:-"
2500 - - - -8000'-----------.......
~
W
W
Ll.
..;.,
Zo
~
<:(2200
>w
..J
W
2100 I-
FOG LAKES SEISMIC REFRACTION PRC
SHEET 7 OF 7
Y WOODWARD-CLYDE CONSULTANTS
81-FL-7
---
10,000
3000 3600---
81-F L-8
---
9300
-2000--2300
2200 ~
LU
u..
1.-.-....._-............-?---
zo
I-<r:>
2100 ~
LU
81-FL-11
17,000
L.lJ
Z
...J
:I:
U
I-<r:
2 2000
-(933)
-__2100
-',--
_ ___8000--"17,000----""'........
L.lJ
Z
...J
u..o
o
Z
LU
LU
C/l
"ION PROFILES
2300
I-
LU
LUu..
z·
0
I-
2200
<r:>
LU
...J
LU
Compressional wave velocities in feet per second
Numbers in parentheses above topographic
profile ref.e.f to survey points
o 100 200
H I I
HOR IZONTAL SCALE
FIGURE 23
.....
'"'"'I
,....
I
I
-.
APPENDIX A*
TIME-DISTANCE PLOTS -SPRING SURVEYS
*This appendix deleted from Task 5,Appendix T.Refer to project files
for Woodward-Clyde Consultants report.
-
r
r
ii
-
r
!
I
r
-
r
APPENDIX B *
TIME-DISTANCE PLOTS -SUMMER SURVEYS
*This appendix deleted from Task 5.Appendix I.Refer to project files
for Woodward-Clyde Consultants report.
r
I
~t
i
l
r""
I,
I'""'"
I
\
r
~
I
l
-
I'""'",
APPENDIX C*
TIME-DISTANCE PLOTS -FALL SURVEYS (FOG LAKE)
*This appendix deleted from Task 5,Appendix I.Refer to project files
for Woodward-Clyde Consultants report.
...-,
I,
r
I
I
r
l
I
!
I
I
-
APPENDIX J
AIR PHOTO INTERPRETATION
~..
ALASKA PC\I\IER ~
SUSITNA HVDRCELECT
SUBTASK5.0
PHOTO INTERPRE
TERRAIN U,NI'
R&M CONSULTANTS!INC.
ENGINEEF=lS GEOLOGISTS PLANNERS SUF=lVEVORS
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5R AUTHORITV
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.ECTRIC PRC..JECT
=lPRETATICN
:NIT MAPS
INTRODUCTION
Th.r.aslbility study ror the Su.ana Hydr-oalectrlc ProJ.c~Includ.s
Q4IOloglcal and g.a~echnlC81 Inv..~lga~lon of the 11,..11 .)(~.ndlng from
the P.rk,Highway &0 mil .....t to ~h.moutt'l of ~h.Tyon.Alv.r
.nd from the o.nall Highway SO mll.,SoOUth ~o Stephan Llk..Th.
mos~co.~.ffec:tJv.m.thod or g.n.ratlng .nd compiling blll.lin.
geologic InfOl"TT\ll~lon about this larg.,Ilttre-lnv"Ugllt'd region il
thr"OUOh U'l4I methodl of photolnt.,.p,..tltion .nd ~rrain unl~mlp-
ping.
Terr"in uni~s compos,d of or Including bedrock ~re shown on the
Int,rpretulon.How.v.r,these divisions .re int.rpreted only u
we.tn.red or un......thered b.drock.Detail.d petrologic designa-
tiOi'll ..nd ..g.r.l.tlon,of the rock units hoOlve been synthesized
frorr'l U.S.Geologic...1 Survey ,ources (Csejtey,1978)and project
fi.ld mapping accompli,hed ~o d"te.Rock unit de,ign..tions 'rom
these sources ..r.includ,d on lhe m.ps.lin....ments.fe.tures-
or-inlarest,end polentlal f.uns hlva not bun shown as their
delinution is outside the scop.or R&M's work.
.authors defined ~h.m and the rock unl~s are ,hOwn only whert thl
photolnterpret.tlol1 loc~hd b.drock on the m.ps.There has be.r
no att.mpt to correl~te units .cross areas of Iimi~ad e)(pOlure or tc
modiry the outcrop p.tt.rn.B.drock symbols are shown In slante<
I.tters with ~he c.pital lett.r,d.finlng the ...g.of the uni~.Inc
following lower cn.letter,de.scribing the rock lYD"
Terrain Unit Descriptions
For thIs photo in~erDretation .xercis••the soil ~ypn,engin,,"in,
prop.rtles end geologicill conditions have been d,veloped tor the !(
l..nd'orms or indivldu.1 t.rrain units briefly describ.d below.
Sev.ral of the I...ndforms h.ve not be.n mapped independently bul
rather u compound or complex t.err-ain units.Compound ~.rraln
units resull when on.I.ndrorm ov.rlies a ,e<end recognil:ed unit
at •sh.,llow depth (less than 2~reet),such as a thin ,heet of
gl ...cill till o....erlylng bedrock or a m.ntl.at I.cu,trine sedim.nts
overlying till.Complex t.rroOlln unit.5 have been mapped were the
surficial .xposure p...ttern or lwo I.lndf:)rms oOIr.so lntricatly relat.d
that they must be m.lpped oOIS •terr.lin unit complex,such .I,,oma
are<ls of b&dro(;k ,lnd colluvium.The compound and complel(
terrain units behave .nd are described iIS a composite of Individu.1
l<lIndforms comprising them The strat:graphy,topographic position
and aruJ extent at all units are SUr.lmarized on the terrain unit
properties and engineering InterpreUtions chart.
Deposits of widely vuying com-
positi~n tha~hoOlve been moved
down$lope chiefly by gravity.
Fluvl~~1 slopewash deposits are
usu.lty intermixed with colluvial
deposits.
orainoo colluvial fans formtd
where solifluction deposits emerge
from confined channel on a hill-
side onto a level plain or valley.
These landforms are often frozen
as derated by "·f".
SOlifl~.clion deposits are formed
by f·o~t creep and tne slo...·
down-slope,viscous flow 0'
satur..t~d soil material and rock
debris in the acti....e layer.This
unit i.generally used only where
obvious solifluction lobu ar.
'ine-Includesid.n~i(iable.
A lobe-or tongu.-shaped d.poslt
of rock.rubble or unconsolidat.d
debrl~th<l~ha,moved downslope.
InCludu rock Ind debris slid..,
.5Jump blocks,earth flows and
debrl1 flow.5.Young slides are
generJlly unfrozen while older
slides m.y be 'roun.
In pl~ce rock that is ov.rlain by
•vary thin man~le of unconsol-
id...tec materl.1 or exposed .~the
surface.Two modifiers h ......
been used (or aU types of b.d-
rock whether igneous,,edimen-
t.,.y )r me~amorphlc.We.~hered,
high I\'frac~ured,or poorly con-
,olidated bedrock is indlcllted by
the ~i(ierio "w"(.II in Bxw);
unweathered,consolidated b.d-
rock i,indicated by the modlfi.r
"u"(as in Bxu).A modifier or
,pedlil symbol 'or 'rozen bedrock
has not been used,although
bedro.:k at higher elevations may
be'r(zen.
CI -Landslide:
Bx -BEDROCK:
c -COLLUVIAL DEPOSITS:
Cs-f .Solifluction DepoSits:
On the maps e.ch terrain unit is identified by letter symbols,the
first of which is capitalized .nd indicates the genetic origin of the
deposit.SubseQuent letters dlHer.ntiate specitic terr.in unin in
uctl group and when separated by a dash,identify the pre,ence
of permafrost.
The terroOlin uni~maps for the proposed SusilnoOl Hydroelectric
Project area show the areoOll extent ot the speci'ic terr"in uniu.
which were identifit-d during Ihe air-photo in....estigltion and were
corroborated in p.rt by a limited on-site surface investiga~ion.
The ~errajn unils,a.5 shown on ~he followino;j sheets and described
in this tex~,do(;ument the general geology ...nd geotechnic<lIl cnu"
a(;leristies 0'the Susitna Hydroelectric Projecl are•.
TERRAIN UNIT ANALYSIS
Limitations of S~udy
A I"nd'orm is detined (Kreig end Reger,1976)u any element of
the I.ndscape which hilS •defineable composition and range of
physic...1 lind visuoOll ch.racteristlcs.Such characteristics can
include ~opogr..phic form,drainage p.ttern.and gully morphel<>gy.
Landforms clilS.5itied into group,bes.d on common modes of origin
<Ire mos~useful b.coOluse similar geologic processes us.ually produce
simil.r top<>graphy,soil properties,and engineering character-
istics.The terrllin unit is defined as I special purpose term
comprising the I.ndforms expecled to occur from the ground sur-
fi!l(;e to a depth of oIbout 25 'eet.It ha,lhe c.pabilily to describe
no~only the mo,t surfical '.ndform,but Ilso,an underlying loOInd-
form when the underlying ma~erioOll is within Ibout 25 feet of the
surftlce (Le.a compound terrain unit),..nd areas wh.re the
surticial exposure pattern of two landforms "re so intim..~ely or
compleXly rel"ted ~hoOlt they muSl be mapped .IS •terrain unit
complex.The lerr.in unit i,used in mapping lanCiforms on an
..real ba.5is.
Thi.!>is a generllized study which is intended to colle-<:t g.cIOQic
and geotechnical materials d.ta tor a relatively large area.Tow...rd
this go"l,the work has b,en su(;cessful,however,there are
cert.in limitations to ttle da~a Ind Interpretlllons which should be
considered by the unr.The engineering ch.rac.teri.!>tics of the
t.rr.in units h.ve been generalized oOInd described Qualitatively.
When evaluating the suitability of iI terrain uni~for a specific use,
~he actu,,1 propertlu of that unit should b.lI.rified by on-site
subsurtace invntig.tion,sampling,<lind labor.tory tesling.
During t.rrain unit m.pping bedrock was identifIed,a,per u-
Ubllshed techniQUes,only <lIS we,thered bedrock or unweathered
bedrock.Details 0'bedrock geology shown on lhe mosaic maps is
deri...,~d from C,ejtey's USGS open file report on The Geology of
the Talkeetna "'Its.(1979)and (rom Acres American (unpublished
data,1981)Th~letter designations are uud here as those
An important fac~or in evaluating the engineering proper~ies,
composition and geologic characteristics of each terrain unlt is
ex~enioiv.(leld checking and subsurfilc.inves~igoOltion.The scope
of ltle current project II110wed only limited field checking .nd all
5ubsurface Investig.tions to d ...te have bftn restricted 10 three
terr.in units clustered around the WaLiin ..site.This lac.k of
ground-truth d ..ta further restricts the use of the terrain unit
mlps and engin.ering ;n~erpretation chart tor site sped fie .pplica-
tions.
Physic.1 ch.lr.derlstlcs and typic.1 engineering propertiu wer-
dev.loped tor ..ch terrlin unit ...nd I,...displayed on •single
ubi•.
The uacutlon or this project progressed through ...number 0'
11ep,that an,urad ~h.accur.cy .nd Quality of the product.The
flrlt Itep conli.~ad of •re....i.....of the literature concerning the
gtOlogy or the Up~r Su,itne Riv,r Buin .nd tr..n,fer 0'the
Inforn'lAlIon galn.d 10 high-level,photographs at •,(;ale 0'1:
12$,000.Interpret.tion or the high-I,...,el photos ,r.ated ...r.glonal
terr"n framework which would h.lp in t~t.rpretation of ~h.
10w-l.v.1 1 :24,000 project photos.M.Jor t.rraln divisions id.n~l
fi.e!on the high-level photos wer.then us.d ,as an .rul guide for
delln,uion of mora deUliled terr.in unih on the low-level photos.
Th.primary .Hort of the subtuk was the Int.rpre~atlon of
JOO-plus photo,cov.ring .bout 800 ,qu.re miles of varied ~errain.
Th.lind ar..cov.r.d in the mapping .x.rclse is shown on the
Ind.x m~p ,hNt <lind displayed In doltail on the 21 photo moules.
Work on th.<IIlr photo Interpr.tltlon .5ubtuk consist.d of severlll
KUvitles culmln"lng in I sel ot T.rr.ln Unil M.ps d.llne.t1m~
surface m.t.ri.ls and geologic features lind condition,in the
project .,..•.
Scop.of Work and Method,of An.lysls
During the low .Itl~ud.photo Interpr'Ulllon a prelimln...ry work
r.vlaw and flald chack was undertak.n by R&M Ind L.A.RJ .......rd,
terrain analYII,consul~an~.A dr.ft edition of the T.rrlln Unit
m...ps and r.por~wu completed and submitted for review to ACRES
.nd L.A.Rivlrd.Comm.nlS and questions generated in the
r.view at the dr..tt report were .nalyzed by R&M and a ,.cond
fl,ld chack wu undertak.n.Th.tinal revised maps lire included
herein.
This tex~and the Iccompanylng t.rraln unit maps pres.nt the
r'hults of ..rlal photograph lnurp,..tatlon and t.rrllin unl~IIn.lysls
for the .,..."Including the proposed W.t.na and Devil C.nyon
d.".,lte .,....,the Susl~.,:llv.r ru.rvolr .r•••,construction
mllledal borrow .r...,and Kce..and tran,mlsslon lin.corridor,.
Th.task wal parformed ror the Aluka Pow.r Authority by R&M
Consultants,Inc.,working und.r the dlr.(;tlon of Acres Am.rlc.n,
In<.
Th.g.n.rll objecllve of lh••xerci,.wn ~o document gtologlcal
taalur.s and g.clkhnieal GOOditlons thllt would significlntly aUKl
lha d.slgn .nd construction of the project fealures.More
specifically ~h.tuk objec~lv"included the d.llnutlon of t.rrain
unl~s of v.rlou,origins on .,rl.,pho~rlphs noting ~h.occur-
r.nce lind dis~ribu~lon of geologic tactor,such u p.rm.frost,
potantlally unstabl.SIO~I,potentially erodible soli $,possible
burl.ct channell,poten~i.1 construction m.t.ri.I".cti.....flood
pl.in,and organic m.~.rlal,.Engineering ch.racteristics lilted ror
the d.llneAted .r..s Iliows .ssessment of ..ch terr...ln uni~'s
Influence on project f....ture'.Th.terr.in unit ...n.lysi,serv.,as
•data b.nk upon which inl.rpr.tatlons conc.rning geomorphoiooic
d.v.lopm.nt,gl.clll geology,.nd geologic history could b.b.ud.
Addl~lon.lly,thIs subtask provides bu.m.p$for the complilltion
and pr.,.nt..tlon of v.rlou,other Suslln..Hydroelectric project
.cllvlllu.
Th••rell of photo cover.ge ....as dlvid'd into unit,of ....orkable
size,r.sultlng in 18 m.p sh.'U.B<lIse maps were prepared from
photo mollieS ..nd ~he terr...ln units were deline.lled on overl.y
sh.els.
SEE SHEET II FOR CONTINUATION
Tel"rain Unit Pr"Operties and Engineering Interpretation Ch.rt
EXisling jeep .nd/or winter sled t"ails have been nOled on (he
Tel"r.in Unit m.aps by a d.sh·dot line.
,
Oeposits of humus,muck and
pUl generally cxcurring In bogs,
fen'and musk.gs.Frequ.ntly
o....rll.s frozen maurial.
o -ORGANIC DEPOSITS:
In order to eVllluate the impact of a lerrain unit with r-a.pect to
.pecifie project f..tures In interpreution of the en9in"rino char-
acteristics of each unit Is.providlN:l.On the chart the terrain
units arlt listeod in horitontal r"Ows and the engineerino pr"Operlies
and p.arAmeters beinQ eV.llu.ted ue listed as headings tOf"uch
cOlumrr.-Within the malrilc formed are relative Q~.litativlt ch,r-
aeterluttons of nch unit.Seve.-..I of the enginee,.ing prope,.tiu
and evalu.ltlon c,.iterl.ar.briefly discussed below,The ch.rt is
presented for general englnnring pl,nning,And envi"lltmmental
auessment purposes.In thl'farm,the data Ire not adequate for
design purpose'but when ~dditional laoor.tory and field inform..-
tion is ,cquired and synthesized,site specific developme.nt work
can be mlOimized .
Hill"crescent,and conea of
gr.nurar ice-cont.c.t deposits
formed by streoMl'a,they now
on or throuOh •gl-eier.
l-f -LACUSTRINE DEPOSITS:Generally fin.·greined materl.l,
lAid down in the Copper River
proglacl.I l.ke .lind grAvelly
nnds depo,itltd In the Watana
CrHk -Steph.n Lake ProgliIC'.1
I.ke.Orten fro:en lIS denoted by
modirier "-f",
Speci.1 Symbols .nd L.ndfo"ms
Buried ch.nnels along the Susilna Rivltl"have been delinul.cj by
\hit LlSit of opposing p.rallel rows of triangul.r leeth.Most of
th...'eatures ara minor .lind should hAva no impact on the present
stUdies,howltver three buried channels.soulh 0'the southern
abutment .t thlt Devil C.nyon d.msite,'hould De In ....utigated to
U'UU potential lukage .round the dam.A.,imll.r but large,.
buried channel extends from ne.r the mouth of Deadman Crull.to
TsuSitna Creek.The trtlugh is filled with qu.ternary sedIments of
$4Iver.l diffe,.ent typ.s and ,oes same or which may ha....e •high
tr.nsmiuibility.Bec.use this chol"nel byp,un the Wataln.damllt..
det.iled work should be dire<:ted towuds delermining its width,
deplh,soil typu,and potenti'l for reurvoir lukage.
In addition to U'le l.a,.rain unit symbols,'flveral special ,ymbol'are
used on the Terrain Unit mllps to denote land,lIde scars,te"rotCe
'carps,fr"Ozen solis,buried ch.nnel,and Iraila.
Well defined '.ndslide scarps,which indl~t.rtlatl...ely recent
'.ilu,...,are shown as tine,following the sc.rp trilCe wIth erraws
indicating the direction or movement.Vi,lble on the ..rial photo,
within m.ny of the terraces .nd outwnh deposit,are '.......1".1
different su,.facu whict'l may be related to Sedimentation .at a
temporary b.,.levltl which wu followed by renewed Incision.The
vllrious outwa,h and streMll t.r,.,ces .Ira noted bY'lines following
the scarps ,eparatlno the different elev.atlon ,urflie-ltS,with tick
m.rks on the side of the lower surt.ce.Permafro,t solis h.v.
been dltline.ted 00 the tltrr.ln unit m.p,through the uu of an -,
'01l0..,in9 the terr.in unit 'eUer d.,19n.tI00.By (:.OOvantion the
symbol -f is u,ed wher-e the permAfro,t i,thought to occur .It
reut dlscontlnou,ly.Sparadlc.elly frozen areas halo'.not been
defined on the maps,however,the possIble OCcurrane.of frozen
"".terill withIn a terrain unit is described in the pree-edlng
se<.tlon on definition'and on the engin..rlng interpretaltion chart.
C~rn,gr.nut.r relatively level
floodpl.in fo,.med by,..l...braIded
streolm flowing from a glacier.
A Oltntly sloping ,one gltnerally
composed of granuLlr material
with v.rying amOunts of silt
deposited upon .a plain by I
stre.m where it inues from I
narraw valley.The priA14ry
depositional .gent is running
water (for solifluction fans,
Colluvial landfor1"ls).Can in-
clude vlrying proportions of
aval"nche a,.mudflow depo,its.
It,peciilly in ll'IOunuinous regions.
Fans are generally untr"Ozen.
Deposits laid down by ..river or
ltrum and flooded during periOd'
of highesl waler in the presenl
s.trum regimel"\.Floodplain,are
composed or two major types of
alluvium.Cenerally granular
riverbed (I'teral accretion)de-
posits .nd gene,.ally fine-grained
cover (vertical ..ceretlon)depoSits
laid down above the riverbed
deposits by strums It bank
overflow (flood)stllQes.
B.ul glacial till sheets,with
,ubdved morphology,
which in the Wat.nil Creek-
Stephan lolk.e ...,"ea are rltl.tively
older (prob.bly deposited during
Eklulna and older glaciations)."d
elsewhere lIS young
Naptawne age.Often f,.ozen in
the W.U1na -Stephan Lake ilrea
with.higher silt ",nd ground ice
content as denoted by modifier
-·f";generally unfrozen In the
Gold Creek -Indi,n River aru;
,nd pOSSIbly frozen between
Wel.na C,,,,p .nd the Denilli
Highw.y.
Rel.tively younOltr abl.tion 1111
sheeh with mor.pronounced
hummocky mo,..ine toPOQr.phy ilnd
less dissected than alder till
sheets.Thne dltposits are pre-
donllne-nlly of the N.ptowne
Claciuion,conlllin .bundent
cobbles and boulders,.nd consist
of wUer-wo,.l(ed till.The .bla-
tlon lill may be sporadic.lly
froun in the D.n.li Highway
ilCCUS corridors.
An old,elevata-d floodpl.in
surface no longer subjKt to
freQuent flooding.Occurs lIS
horizont"l benches abO..,e present
floodplains,and generoily com-
posed of m.tltrl.l$very similar to
ilctive floodplains.
Long ridges of gr.nulolr ielt-
contact deposils formed by
Slreilms as they flow in or under
•glacier.
Fpt -Old Ter,..ce:
GFo -Outwash:
G~e -Esker Deposits:
-
Fp -Floodpl'in:
Fro -Granular Alluvial Fan:
Glb-f -8aul Till:
Ct.-~:
Ice rock that is overl.in by
y thin mantle of unconsol-
m'terlat or ex pond at the
Two modifiers h.ve
used for all types of b.cl-
whether ign.cus,sedimen-
>r tnetMfl(lrphic.Wuthered,
fractured,or poorly con-
led bedrock is indicated by
'IOdifiers "w"(as In Bxw);
thltred,conlOlldated bed-
is lodie,lited by the modifier
as In Bxu).A tI'IOdifier or
I symbol for fr"Olitn b~rock
not been usIN:l,.lthOlJgh
:k at higher ele....tions molY
its of ....idely vilrying com-
)0 that have been moved
lope chiefly by gravity.
I slopewash deposits are
y intermixed With colluvi.1
its.
e-or longue-shaped deposit
:k rubCle or unconsolidated
.that hu moved downsloplt.
les roCk and debris slides,
blocks,earlh flOWS .nd
flo.ws.Young slides a,.e
lily uMroun wh'r.older
moly be frozen.
clion depos'ts .re formed
'ost creep and the slow
slope,viscous flow of
led SOil m.lIleri.1 "nd rock
in the ,,~!-I,yer.-This
;gener.lIy used only where
SOlifluction lobes Ire
·iable.Includes 'Ine-
colluvi.l filns formed
solifluction deposits emerge
confined channel on .a hill-
..,to •level plain or v,lIey
l.andforms are orten frozen
oled by "_f".
its are shOwn only where the
the maps.There hn been
..s or limited exposure or to
symbols ..re shown In slanted
'0 the ~e of the unit and
h.rack type.
the soU typn,engineerIng
"e been developed for the '4
:s briefly d.scribed below.
In mapped independently but
in units.Compound terrain
ies •second recognized unit
:).sueh u •thin shut of
Intle or l.custrine sediments
h.ave been mapped were the
)N'!1S OI,.e so Intricatly releted
I unit complex.such as some
rhe campound and complex
I as a eampesite of individu.l
graphy,topogr"phic position
!'Imarized on the lerrAin unit
,ns chart.
L
oml ALASKA POWER AUTHORITY~~nlO II,I---s-u-s-,T-N-A-H-Y-O-R-O-E-L-E-c-r-R-,-c-P-R-O-J-E-C-T---J
SUMMARY REPORT
.U.TA.K 8.0.
PHOTOINT.RPR.TA~ON1/\
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1/\
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OAT(NO.REV1$1(lHS tH.An.An.
,l[~fr\'\7II1.""OCTOBER 19BI I ~".~J/~J..\J'.!--l.....,•..,1····'··0•..all~u.l"C.
·"01\1:'062502 ,...., I O'Mil IA
EnglnHrlng Interpr-etltlon Definitions:Ground Watlr Table Depth to th,ground water t.blt
is described in relalive terms
ranging from very shallow to
deep.'n construction inVOlving
excavation and founddtion work"
speditl techniques dnd pldnning
will be required in most .redS
with II ShdUOW water (.bl.and in
somt of the arus with a mod.r-
ately deep wllir t.ble.In IIrlllS
of impermedlble permilfron ..
shilliow perched lacill wlter table
m.yoccur.
preStnc.of permafrost moly
signitic.nUy the
.trer gth of some 'ine grained
solis (as indicaled on the Chart
by Itle Ihermal state qualifying
statlm.nt).
Gre..:quanties o(borro.....mati"
rials.wilt be needed ror all
phas~s or construction.ihe
rating considers su1tilbil,ty as pit
run and processed aggragete Of
impe,'vious core dnd takes intc
accotlnt Ihe materials present al
well as the problems associate,
with extracting material (rom tht
varicus terrain units.
The slope .tabililY C!uillit.ti\l!!
rating deri\led throuoh
eVilhl.tion of ~ach terrain units'
toponrilphic position,slope,soil
composItion,waler content,Ice
cont'!nt,The stability
asse~sment consIders .11 rllpid
wuting processes (slump,
rock slide,debriS slide,mud-
flow,etc.).Sevllral terrain
units which hCl\le character-
istic"lIy g!!nt1e slopes and are
comrn:mly in stable topographic
positions ha\le been oversteepend
by the reclnt,ilctiv.under-
cutting of Slreams ilnd/or m.n
(or by older p ..oeenu not
curr~ntly active such .s glllci.l
erosi:>rl and tectonic uplift and
fault ng).The stability of lhe
ttrr<;in units on ovt'rsteepend
slopu and "iltur.'slopes is
described on Ihe Engineering
Intel-pret<ttion Ch.rt.
Suitability as a Source of
Borrow
The major topographic features of southcentral Alaska were es'
tablished by the end of the Tertiary Period.What is now the
5usilna p ..oject area was located in the relatively low northern
portion of the Talkeetna Mountains,which separated the broad
anCUtral Copper River Basin lying to the east from the ancestral
Susitna Cook Inlet Basin lying to the west.North and south of
the i alkeetna Mountains and the adjacent large river basins stood,
respectlvily,the great arc of the Alask..Range and Chugach
Mo,,!~alns.Streams draining the region that would become the
project stUdy area may have flowtM:I into either the ancestral
Copper or Susitna River systems.During the Pleistocene the
l!ntirl!Susitna Project study area was repeatedly glaciated.Eac"
of the glacial events would be e)(pected to follow the same general
pattern with several advances most I.kely reilching the maximum
event described here.
REGIONAL QUATERNARY GEOLOGy
Slop!!Stability
Quaternary glacial e\lents throughout South-Central Alaska pro-
foundly affected Ihe soils,landforms,and terrain units occurring
10 the project areil.ThtS history has been discussiKt and parli"lIy
deciphered in paper~by Karlslrom (1964).Pewe (1965).Ferr'ians
(1965).and wahrhafting (1958).However,these in\lestigations are
of such scope as to make them of IirnltiKt v<ilue here.The phOtO"
interpretation and resullanl lerrilin unit mapping is the most
detailed study or the Upper susitnil River Basin.The following
discussion o(Ouaternary Geology IS a synthesis of the new infor-
mation,deriv!'d durinQ the pholointerpretation,supplemented by
data from published sources.
Permafrost sotls with iI sign-
ificant volume of ice may shOw
some settlement of the ground
surlace upon thawing.In gen-
eral,Clays,silts and fine sands
have tne g~iltest settlement
potential,torming the buis for
the three told classification
presented on the chart.Un-
frolen soils do not hilve Ihe
potential for thaw settlemenl,as
denoted by "not applicable"
(NA).Thawing problems may be
initiated accelleraled by
disturbance of the surficial soil
la~~_r;..s or the organic mal.
Based on the terrain unit soil
types and stratigraphy a qualita-
tive description of bearing
strength is given.In general
CO<lrse grained soils have a
higher bearing strength than
fine grained soils,bul the
Thllw Settlement Potential
Prob.ble Permdlfrost Distribution The occurance of perrn.rrost
and the degree of continuily of
frozen soil is described on thl
Engineering Interpretation
Chart,by th,following relative
terms:Unfrozen-generally
without .ny permafrost;
Sporadic -signific.ntly large
areas are frozen.Site splcifiC
work may be required before
designj Discontinous -most of
the arell is underLain by frozen
soils -site specific work is
required unless design incorp·
orates features relating to perma'
'rost;Continous -lhe enlire
area is frozen.All designs
stlould be based on occurrance
of permilfrosl.
FrOSI Helve Pot.nlial "Those soils which contain signi-
ficant amounts or silt and fine
sand have the potenlial to pro-
duce frost heave problems.
quaiitative low,moderate,and
high scale rates the various soils
bilsed on the potenlial severity
of the problem.Where Ihe soil
stratigraphy is such thaI a frost
susceptible soil overlies a coarse
grained deposit,a dual classifi-
cation is given;for these soils il
may be possible to strip off the
frost sU5eptable material.
8ued on the IlIbor.illory test
results,field obser-vlltlons,
pr,wlous work in sirnillir IIr..s,
and definitions of th,soils,II
rllnge of unified soli types hili
b,en nslgned to uch terrilln
unit.Often se\ler.1 soil types
,r.Ilst.d,som,of which .re
much less pre\lel.nt th.iln others.
Informlltlon In the soil
str.iltlgrllphy column will lid in
understandlno the r.ng.Ind
distribution 0'soli types.Study
of the borehole loos lind Ilib tut
rnults will glv.site specific
unified soli types.
Erosional potential as described
here,considers the matenals
likelyhood of being moviKt by
eolian and t1uviill procesns such
as sheetw.sh,rill and gully
formation,ilnd larger channelized
flow.In generill this reliltes to
Ihe par~sile of the wil,
however,the coars~sediments of
floodplains have 'been rdled as
high because the surface is very
dctive,dnd likewise
terrace depOsits Cdn have a high
r.ting because of their proximdty
(by virture of the their origin)
streams.(MiSS wil~ting
potential is conSidered under
slope stability).
Following guidelines estlblished
by the U.S.Forest S,r\lic.,th,
Bur...u of L,nd Mln-oement ,nd
the Am,ric.iln Society of lllnd·
SClipe Architects,,lopes in the
project corddor h.il\le been
divided Into the following
dun,:Flllt·0 to 5\;GenUe -
5 to 15\.Mode,..te •15 to 2S\
lind steep •grellt.r than 25\.
R.fe~nces hll\le been mild.to
steep loelll slopes to Kcount for
."...11 IClirps Ind the slmll.r
short but steep slopes which
c.hllrllcterize iCe conLKt glifCili1
drift.
How the solis comprising the
t,rr.in unlts handle the Input of
w.ter is chllrllcterlzed by th,ir
drainllge ilnd prerneabilily.
Permellbillty (hydraulic conduc-
tivity)refers to the rllte .t
which water can fiow through a
soil.Drain.ge describes the the
wetness or the terrain unit,
taking into account iI combinatIon
of premeability,slope,topo-
graphic po~ition,ilnd the prox-
imaty of the water table
Prol»ble Unlfl.c:J SOU Types
Erosion Po(enti.1
.;
tnce of permarrost m<1ly
fk.ntly Incruu the
gth or some fin,grained
(as indicated on the chart
he thermal sUte (;lu.Jifying
ment).
slope st-lIbiHly (;lualit,lItive
dtrived through
'ation of e.ch terrain units'
lraphic position,slope,soil
osition,w<1lter corltent,ice
,nt,Th.stability
,sment considers .11 rapid
wasting procenu (slump,
slide,debris slid.,mud-
etc.).Sever.1 terrain
which have Charicter-
Illy gentle slopes .lind are
only in stable lOpogrtiphic
ions htive been Oversteep.nd
the recent,.ctive under-
'101 of streams and/or man
by older prOCesses not
tntly active s\.lCh lIS glticial
on and tectonic uplift and
ng).The slability of the
in units on over-sleepend
sand naturtil slopes is
'Itled on the E.ngineering
pretation Charl.
I quanties of borrow male-
will be needed for all
~s or construction.The
9 considers suit.Jbility as pit
and processed aggragete or
'vious core anCl takes into
Int the materiills present as
u the problems auo(.idted
extr.Jcting materiAl from the
us terrain units.
South-Centr.JI AI.Jska pro-
and terrain unilS occurring
been discussed and partially
964),Pewe (1965),Ferrians
lier,these investigations are
ted value here.The photo-
unit m.apping is the most
River 8.asin.The follo....ing
synthesis of the new infor-
'prel<ltion,supplemented by
Juthcentral Alaskil .....ere es-
I Period.What is now the
the relatively low northern
which separated the broad
the eilst from the ancestral
NO\l~and sou.th of
lnt large river basins stood,
ll,luk.J Range and ChugaCh
lion th,at would bKome the
into either the ancestral
During the Pleistocene the
repeatedly glaciated.Each
d to follow the same general
ikely reaching the maximum
The onut of a given glaci.1 adv.nc.in Southce.ntr.1 Alask.a would
be.mark.d by the lowering of the snowline on th.regions
numerous mounUiin ranges and the Or"Owth of vailly glacilrs,first
in tht higher ranges .Jnd those closer to the Gulf or Alaskti.
Ad",.ancing glaciltr$from the Chugach,Wrangell,Alaska .and
southern Talkaetnd ranges would flow out of their ",.alleys Ind
coalesce to form I.rge piedmont gllciers sprUding across the buin
floors,while the ice of the northern Talkeetna Mounlains (in the
project ar,,)would still exist iI$valley glaciers.The piedmont
glaciers of the ChugtiCh and Wrangell MounUiins would at some
point be expected to merge,damming the ancestral Copper RI",er
and creating an extensive prOQlacial Like in the Capper Ri"'er
Ba~jn.Alaskd Range glaciers flowing southward would block.
ponible ancestral drain.Jge piths of the upper Susltna River
creating.second lake which COvered much of the project area and
merged with the lake filling the Copper River buln.Glaciers
flowing from the Kenai Mount,ins and southern Alaska Range ....ould
also merge creating another proglacial lake in Knik Arm,Cook
Inlet,and the Southern Susitn4 Basin.Continued glacial itdvance
would fill the basins eliminating the lakes and ponibly forming an
ice dome.ICe shelves may hll"'e extended mlnv miles into the Gulf
of A/l5k.J.At this maximum stage many mountains in the Pl"Ojtct
<1Irea were completely buried by ice as evidenced by their rounded
summits ....hile numerous others e;.;isted as nunataks.
The deglaciation of Southcentral Alaska would rolla....a similar
pattern but in ..everse.w.sting of Ihe ice would unCO"'er p_ks in
the project aru and the thinning "nd retrellt of the glacien in the
Copper Ri"'lr,Uppe..Susitna anCl Cook Inlet regions would again
allow lakes to torm.Continued melting of the glaciers would
remove ice dams blOCking the proglacial lakes possitlly creating a
catastrophic (trench cutting)outburst flood.Intervals between
glacial ad"'ances would be characteriUd by the fuvial entrenching
of the Susitna and Copper Riven and the,r tritlutades.The
earlier glacial events of the Quaternary Period are poorly known in
the Upper Susitna Basin due to bOlh the erosion of the older
deposits and tntir burial beOtalh young@r deposits.How@ver,
from the alpine topography Ind minor glacial sedIments left on high
slopes il can tle demonstrated that early Pleistocene glaciers
completely (overed Soutncent..al Alask.il as in the maximAl event
described tibove.Most of the glaei.l deposits th.t remain and the
terrain u.,its used to describe them ha",e resulte.d from later glacial
events.
The last gl.Jciation to completely COVelr the project area is of un-
certain age.1t has been interpreted to be of Eklutna dge by
Kolrlstrom (1964)which may be cerrelate.d with the Illinoiln glacia-
tion or ttl.Continental United 5l<)ttS (Pewe,1975),hOWII'''''er,with
the limited datil a"ailable .In early Wisconsin (Knlk)~e may be
just as vi.Jble.Whatever the age,ice flowing from the Alaska
Range,the Talkeetna Mountains and several local highland c@nters
spread across the proj@ct lowlands depositing a sheet of gray,
gra",e!ly,sandy and silty,basal till (Glb-f).The till ",aries
greatly in lhi,kness,ranging r..om the 100~feet,displayed in some
river cut e)(posures,to a thin bl"nket ovu bedrock.This till
presumably overltes older,poorly exposed Quatern.ry sediments.
It IS recogniz.d that the basal till,mapped as Gttl-r in the
Stephan la~t-ana Creek Area may actually represent several
closely related e"'ents and th.t basal till in "'alleys north of
Deadman l.Jke and downstream of the Devil Canyon site was
p ..obably deposited durrng younger glacial Cldvances.Prominent
lateral mor.Jinu of the major .Jd"'ance occur on the flanks of
mount.ins bordering the central Watana Creek-Stephan lake
lowland.
Overlying tne bdsal till unit and representing the next major
depositional evei'll is a lacustrine seQuence.Pres':l.,T.bly the
Idcustrine materidls were deposiled during the Eklutna (?)Glacial
retreat and during mUCh of the younger Knik and Naplowne glacial
events.During these st.1di.J1 events glaciers from the Alask.a
Range blocked drainage down the present Susitna channel and
probably througn a low divide between Watana Creek and Butte
Creek;Talkeetna River Valley glaciers tllocked low divides between
1/\
Stephan \..Ike .lnd the Talke.tna River;end the Cop~r River
Bollin wu occupied by an ext.nsiv.progl.c:I.l1 l.k..Th.
l.aeustrln.deposits mApped wIthin the project ilru as Land
L/Gtb-f,cover much of the W.lIna Cr••k-St.ph.n L.ke lowland
And ell tend upstream .lIang the Susana River to the Susltn.-
Copper Ri.......Lowllnd.In the WIUna CrMk-Stlph.In Lak.
Lowland the unit Is generilly l.n th.n zo te.t thick and compos.d
of medium to fin.sand with.signiflc'nt grav.1 content.Th.lak.
deposits of the Copper Rivtr Lowl.nd .Ire thought to b.mueh
thicker Ind finer-gnlined.Th.coarseness of thl lacustrin.
sediments (i.•.grAvelly unds in the W.~nl Cr"k~St.phan l.ke
.aru )is not unexpected .IS the .ncient l.k.wu impound.c:l b.hlnd
and ringed tly glaciers which w.re activity c.lving into the I.ke.
During tn.Idte Neptowne glaci.1 event,In the W.lUin.Cretlk-
Stephan L.ke portion of the preglaci.1 l.ake,severaf delt..".nd
strand line futures we,..form~.t .bout the 3,OOO·foot .Ievation.
This shoreline lev.!Is higher th.n most ....portld snorelines of the
p"OQlacitil I,k.occupping the Copp.r River Buln.It is possible
then,thlt during the N.ptowne s~ldial the WlUina CrMk -
St.ph.n L"ke progl.d.l I.k.stood It a higher l.vel bee.un It was
impounded tllhing another ice dam in the Kosina Cr..k •J.y Cre.k
It IS .Iso possible In.Jt .In outlet exsist.d for much of the
life of the I<lke (conceivably in Kosina -Jay Cretk .ru).Flow
from the I,ke would remove greet qu.ntitles of fine grained
suspended s«diment,c.ilusing •rellti",.increls.in the coarsen.ss
of the sediment deposited in the I.ke.
HummockV coarse gr/llned deposits of .ablation till (Gt.l)overly
lacustrine sediments between Tsusen••nd Deadm.n C....ks .nd
basal till in tne valleys north or Oudm<ln Creek And in the Den.aJl
Highwtiy aru.These millerlals may be correl.tive with eskers and
kames found Iiong the Susitna RIver between thl Oshetnl and
Tyone Rive"s,and together they repruent the ext~nt of the last
major Adv.nce of gllcill ice into the prolect .rl!.l.Thev Ire ten-
tatively determined to be of N.plown.age (Late Wisconsin)
(Karlstrom,1964)suggesting th.t the Knik Age glaciers wire less
extensive and their deposIts were overridden .nd m.lsked by
Naptowne deposits.Lacustrin.sediments of the large glACi.1 I.ke
occupying the Stephtin Lilke ~W.tana Creek lowland l"l.",.not been
mapped oVil'rlying the abl4ltfon till,indictiting th.t some of the
abl<ltion lill Ind ancient W.tln.Creek-Steph.n ll""l lacustrine
sediments were time syncronus Ind thAt the pr09laci.1 I.kes were
drained shortly .fter the Napto.....ne mAximum.One should note
that stver,l isolated deposits or ablation till .Ire not necessarily
indlcati",e of this lite .dv.nce and ice.of Nllptowne .ge did not
deposit .blation till In all 1()(~i1ities (most importantly In the
Portage-Devil Cruk Irel Ind in the .ru between DUdm.n Lake
Ind the Denali Highw.y);and that lacustrir')e sedimenu deposited
in s.mlllil isolOitea progl<lcial I.kes have been found oVlrlVing
abloiltion till.
Interv.ls between glacial .Jd"'OInces would be chlrOieterized by
fluvial erosion And entrenChing of the project areA po..tion of the
ancestr.1 Susitnd and its tributary stre.ms,however_the majority
of the inlentadial fluvi.l hisory hn b.en destroyed by subsequent
glacial and r1uvial history.Remnants of Ihe older entrenching
events a ....preserved in several .Jbandoned and buried chlnnel
sections along the modern Susitn.River ..~ne of the largest o-Ider
channels fOund,.It the Vee Canyon damSlte has.bedrock f1GOr
(cut below 'he tledrock floor of the pruent Susitna chann.l)which
Is now filled wrth fluvial and glacio-flu",i.1 debris.The second
tluried chotnnel,tletween Deadman .Jnd ·husen.Creeks,just north
of the W.Jtana site Is filled with out....uh and lacustrine materials
with intervening till layers (Corps of Engineers,1979).Bec.use
ice oI:>,.~',r"apto....ne and Knik ilges presumably did not completely
cover the project area,and the tll!s in the channll ha""character~
istics simil.r to the btisat till unit attributed to the
Eklutna GI.Jciation,it appears that •portion of lhe .~ceslral
Susitna River v,llley of similar size and depth to the pres.nt valley
existed .IS ur1y as the EklutnA GIACi.1 event (Illinoian).Eklutna
age till and associated l.Jcustrine sedim.nts also filled some of the
presltnt Susitna v"lIey,however,most have be-en substQuently
excavated The Eklutnl .e;te v.Jlley may have bun grade<l to drain
SEE SHEET III FOR CONTINUATION
J
[IPO[P I!I--_A_LA_S_K_A_PO--,.W_E_R_A-:-U-,---T-:-HO-,-R_IT_Y----I
ItUnlO J,SUSITNA HYDROELECTRIC PROJECT
IIUBTABK B.OII
PHOTO INTBRPRBTATION
1/\
1\
/\
/\
NO.CH.An.A"".
SUMMARY REPORT
S2»~IAl-::::,,~~:OBER19BI ::::~.a.a I~'"a.Ltom"illt'B'MH-1\.
~O\OJfCT 052502 '....T II O'1111
REGIONAL BEDROCK GEOlOGY
Tbgd Tertiary biotite grano<lIorite forming slocks ..../lich
MiljOr bedrock lithOlogies as mapped by (wltey,and included on
the terrain unit map},df"e summarized as follows:
On numerous slopes in highland areils (as long Dtvil Creek)and
on the broad lowl"nds solirluction hdS modified the surficial glacial
till "nd/or lacuslrine d.posits.
Tertiary schist,mignatite.and granite which
display gradational contacts.The schist dnd
lit-par~lil migmatite are probably products of
contact metamorphism \~ith the enlire unIt pOSSibly
repre.senting the roo:of ,)l..roe stock.The
rocks occur in apprxolmately equal proportions
wilh the largest exposures occurring in Tsusena
Bulte,wesl of Deadmdn Creek,and in the rec-
Ulngul,)r sovthern jog in lhe Susitna River.
Csejtey maps this unil at the Watana ddmsite,
howevltlr,more recent field work (ACRES,1981)
h,)s shown that thl"Watana damsite bedrock
consists of diorite and ~ndesite.
Creek.
Tertiary and/or Cretaceous grdnitic rocks forming
small plulon$the largest of which is found in tht
headwaters of Jay Creek.
Cretaceous argillite and graywacke of a thick
intensely deformed f1yschlike turbidite sequence.
LOw grilde dynametam"rphism to the low green"
schist facies ha~<Il1c ...·ed se...eral edrly inve51i-
gators to rn,)p portions of this unit as phyllite.
The graywacke beds f::/rm about Jot to 40~af the
unit and tend to bf'clustered in zones 1 to 5
meters thick.This [,nit is exposed at the De...il
Caflyon site.It exter..ds downstream beyond Gold
L'·eek and forms the nountain 'mmed;,)tely easl of
Gold Creek.
Tria:ssic basaltic met,wolcanic rocks form in a
Shdllow milrirle environment as evidenced by thin
interbeds of metachert,drgillite and marble.The
indi...idual flows are I"tported as op to 10 meters
thick dnd displdying pillow structure and colum-
nar jointing.This un I is mapped,in the project
area,in the mountains ~dSt of \Valana Creek.
Triassic metabasalt and sl"te in an interbedded,
sn..llow marine sequence found In two allochth"
blocks in the upper sections or Portdge
L",le Palt'Ozoic basallic dnd andesitic metavolcano-
genic rocks which forrn of broad band across the
central Tall<.e~tna Moult<.iins from the southweSl to
the northeast.The 5,000.foot sequence is
dommantly marine in ilrigin suggesting ttlat it 15
part of d complex '/olc.lnic ore syslem.The
majority of the band of this unit crosses the
project area just west cf T5isi,Kosina dnd Jay
Creeks.Near the lop of this unit several
metamorphosed limestcre red deposits (Pis)ha...e
been mapped.
Jur,)ssic amphibolite with minor inclusion~of
greenSChist and o<:cas'onal inlerlayers or marble.
The unit Is probably deri...ed from neighboring
bdSlc volcanic formdt!Qns.The dmphibollte ex-
tends (rom the Vee Cdnyon ddmsite downstream
for about 12 miles..)ther Jurassic rocks .....hich
occur in extremely limiled exposures include
Trondjemite (Jlr)and granodiorite (Jgd)
lithologies.
dre believed to be the plutonic equivalent of unll
Tv.The most exlensi...,exposures are found on
eilher side 0'the Susitna River from just up-
Slream of the Devil Canyon damsite to the
northward b.nd in the river ilbout sill:miles
upstream or Devil Creo!k.An outcrop of Tertiary
hornblende granodiorite (Thgd)is located just
west of Stephan lake.
Tsmg
TRvs
TRv
TKgr
J.M
Tertiary volcanic rocks of subaer;"l :lOd sndllow
intrusive origin with a total Ihic~nf'SS of oller
1,50;:1 feel.The lower part or I "It!sequence
consists of small Stocks,Irregular dikes,flow:;
and thick layers of pyrocld..tic rocks of quartz
Idtite,rhyolite and lalile comPOSItIon.The upper
part of the $equence consists of andesite ,)nd
basalt flows interlay~.....ith tuff.These rocks
are mapped in Fog Creek dnd its malor tributary.
Tv
J=iNllly,revegetation of poorly drained portions of the landscdpe
hu produced numerous sCdttered deposits of organic materialS
(0);,lind permdfro5t has de...eloped in m,)ny are,)s.
Tht bedrock geology of the Talkeetna Mounldins and Upper Susitna
Ri ...er Basin is ell:amined in numerous public<iltions varying in
nature from sile specific to regional.The mOSI comprehensive
report is by Be'a Csejtey (1978).entitled the Gt'OIogy of the
Talkutna Mounta)ns Quadrangle This paper ind map deals with
the <!Iges,lithology,structure,"I"ld tectonics of the regions rock
units His rnults,supplemented by unpublished data from recenl
project field mapping,are Ihe b,)$is of Ihis report's bedrock unit
identification.Csejley (1973)concludes that soulhern Alaska
de...eloped by the accrellon of a number of northwestward drlltlng
continental blocks 01"1 to the North American plale.E,)ch of these
terrain5 had a somewhat indepel1dent dnd varied geOlogic history,
consequently,many lithologies with abrupt and complex contdCU
,)re found.(sejtey notes that "the rocks Or lhe Talkeetna
Mountdins region have undergone complell:and intense IhruSlin9,
folding,faUlting,shearing,and differential uplifting with as-
s.ociated regional metamorphism,and plulonlsm".He recognizes at
least three major periods of deformation:"a period of inlenle
metamorphism,plutonism,and uplifting in the Late Early to Middle
Jurassic.,the plutonic phdse of which persisted into Ldte Jurassic;
a Middle to Ldte Cretdceous alpine"type orogeny,the most intense
and Important of the three;and a period of 1""It,ll"mal and high-angle
rellerse fdulling and minor folding in the MlddHIL Tertiary,possibly
extending into nl.Quaternary".Most or the major structural
reatures of the Talkeetna Moun~dins lrend northeHt to south.....est
and \<!o'ere produced during the Cretaceous Orogeny
Tsu Tertiary nonmarine sedImentary rock~inclUding
flu ...iatilt conglQmtrllte,sandstone,<'Ind claystone
with 11 few thin :il)nile beds The only known
exposure:s of this unit ,ve in Watana Creek
The development of a number or landslides (C I)has occurred
throughout the project i1reoil.Most landslides were found within
th.,bual till unit (Gtb-f or L/Gtb-f)on steep slopes "bove
acti ...ely eroding streams.The Incidence of failure within this
lmlteri"l ilppears to De strongly reldted to th,)wing perm.frost "nd
consequfllnt soi!utUI"i1tion.The baul till unit is frequently over-
I"in by Idcustrine material and the lacuslrine materials rail with the
till.Most railures occur as small shallow debris slides or debris
flOws,however,a few I.arge slump failures occur.The slumps and
deDri~flows are marked with d special symbol on the Te.rrain Unit
"".liPS Steep rock slopes are a~5umed to be slable.However,Ihis
;s undoubtedly not the case where unfavorably oriented dis-
continuitiflS dip out of th.rock slope.Such discontInuities must
be identdie<l and their effects assessed during on-site rock slope
stability investiguiof"ls.
The present course of the Susltn"River wu probably established
durIng-or betoNl the Wisconsin GI.cial events.Sandy gl"c;al till
observ.d nur the river level .t the O....iI Canyon site m"y h,we
been deposited by the gldciers forming the Naptowne Age ice dam.
If this Is the cue,,lind the till is in-situ then most of the bedrock
downcuttlng and removal of Quatun"ry sediment from the Susltnd
channel was "cc..omplhhed b.rore the end of the Wisconsin If the
till daposit near w"ter lev.l in Devil C"nyon is older than the
N"plowne event (Knik or Ekultnil),it would
indiclte,"n '411"lier Incision date .nd Iha!the river followed its
present course since the E.Jry Wisconsin at least.
Other minor ch.ilnnel remn.ilnt5 include three buried channel5 .ilbove
.nd ~th of the soulhern .butment at the Devil Canyon dam51le
that m.y be ,..I.ted to the dridn.ge of ,proglaciil lake or an older
position of the Susitna River.The channels are prob.bJy 5hallow
but shOUld be thorougnly Investig.ted to usus potent;"J leak.ge
.round the dMTI.A.small,p"rtlally b\.lried channel downstream of
Port-oe Creek "nd another nur the mouth of Devil Creek are
~n.nts of the aownc\.ltting phase of the Susitna Ri ....r.Similar
chann.l,are round n••r the river level Just upstrum of the
Wayn.Damslte .llInd downstream of W.tana Creek.
Frost craCking,cryolurDdtion snd gravity nave combined to form
numerou.s colluvial deposits.Steep rubbley tillus cones hllve
accumulated DeJow cliff5 and on slightly less precipitiOus slopes
thin deposites of frost churned soils cover bedrock terraIn (C).
Numerous rnodifiCoIItlon,of the glacIated tourtacu and Ihe develop-
ment or non-gllclll Iindrorms 1"1011$ch"racteril.ed the Sustinl project
.ral sinc.the PleisloCel"le.The strum incision,as previously
discussed,hIS produced or at leut eXcllvltfl'd tl'le V-shaped
Susltna River V"lIay within the wide "I",(l"t.d v"lley floor.This
holls rell.N.nated mllny tribut"ry stream,which are now down -
cutting In theIr channels,.IS is e...ideI"lC.d by the steep gradients
In the low.r portions or their channels,lower gradients in the
mld-chollnnel sKtlon "nd frequently •waterfall niche -point
sepollr.ting these stre.m segments.Severdl low terr.cfl~(fpl)
h.v.been formed .bo....the modern floodplain (Fp)of the Susilna
lind Its major tribut.riu.TerraCf15 at several different levels
were found throughout the Susitn.Rlv.r Valley.Some occur high
on the v,lIly w"lIs .IS eroded terrace remnants (upstream of W.tanil
Creek);while others "ppur as very recent,10.....,flilt plimar
futures.N..r the moulh or Kosin.Creek and In severdl other
loclltions,the terrace mat.rials overlie relatively shallow bedrock
such that they m.y more "ccurltely be called be.drock benches).
Between the Oshetna and Tyone RI ...ers the thin terrace gravels
overlie gllct"l till.The terrdces lire frequently modi(ie-d by the
deposition 0'oIIl1uvllll riln debris (frg)and/or the flow of solitluc-
tlon lobu .nd sheets (Cs)across theIr surfilces.Correliltion of
the terrace levels on the dir pholos is dIfficult because of the lack
of continuity ilnd was,therefore,not attempted.In the Gold
Creek are"three diffarent,low Ilvel t.rraces are clearly visible
"nd in the Tyone-Osnetnl Rivers are,ll four terrace levels un be
disc.~ed.Between these IredS the le!"T'K&4 rdrely occur in
groups "nd i1Nl more widely sp,Ked.Most tributary str.ams also
show multiple terrdce levels with Ihe best example being in
Tsusena Creek where fi ...e or more levels ,)ppear as steps on the
vililey wilf!.
The stream terr"ces are rrequently modified by the deposition of
oillluvial totn debris (Ffg)and/or the flow of solifluction lobes and
sheels (Cs)ilcross Iheir surfilces.Alluvial fans have also been
deposited whllf"1l steep sm,lll drainages deDouch onto floors of wider
glaciated vall.ys.
..st Into the Copper River Buin.The f"ct th"t the pruent
Susltn.RIver flows in "deep canyon KroSS mount.illnOllS terrain
(in the Portage-Devil Creek .nd Jay·Kosin.il Creek <lIrus),iilnd not
KroSS the low Susitna-Copper River of lhe Stephln lake-Talk_tna
River Divldu may be the rnult of glaci.ill derangement and/or the
rapid drainage of proglacial lakes causing .iI pirilting of portion5 of
the Copper and Talkeetna River drain"ges.
plutonic equivalent of unit
ve expo!wres are found on
.silna Rivu from jusl up-
Canyon damsile (0 the
:he river .bout ~ix miles
~k.An outcrop of Terti.ry
:e (Thgd)is located just
latite,and granite which
ont~cls.The schist and
are probably products of
~ith the entire unit ponibly
r of a l'lrI~e stock.The
<oimately equal proportions
sures occurring in Tsusend
an Creek,and in the rec-
g in the Susitn~River.
lit at the Walalla damsite,
field work (ACRES,1981)
Watana d<ilmsite bedrock,
mdesite.
:eous granitic rocks forming
1St of whIch b found in tl'le
k.
with minor inc.lusians of
(mal interlayers of marble.
derived rrom neighboring
The amphibolite ex-
:anyon damsite downstream
)lher Jurassic rocks whiCh
limited exposures include
and granodiorite (Jgd)
>volcanic rocks form in it
ment as evidenced by thin
Itrgillite and marble.The
~ported as up to 10 meters
)illow structure and col urn-
t IS mapped,in the project
~asl or Watana Cree ....
and andesit,c etavolcano·
l'd broad bane-"eross the
lains (ro."O Ihe southwest to
5,000.(001 sequence IS
lrigin suggesting Ihat it is
'olcanlc ore system.The
of this unit crosses lhe
r Tsisi,Kosin.and Jay
op of this unit several
e reef deposits (Pis)'have
nd graywacke of ~,Ihick
s<.hlike turbidite sequence.
)rphism to the low green-
wed several early investi-
s or this unit as phyllite.
)rm about 30~to 401.of the
clustered in ZOlle~1 to 5
nit Is e:xposed at the ~evil
d~down.trl!If1 beyond Gold
nounilltn immediately easl o(
d slate in an interbedded,
ICe found In 1WO allochth-
upper sections of Portage
Several of the above units have been used 10 describe rocks
m~ppe<l by Acru between (he Watiln,)and Oevil Canyon d~msites.
Where Ihl1:dat~wiiU dvailable it took precidence over Csejtey's
map.
Listed betaware some references which may be o(help in provid-
ing background information and/or details concerning tn.soils and
bedrock of the project area.
Anon.(1978)Seismic refraction velocity profiles and discussion,
Watanil and Devil Canyon Damslt.,.Sh.jmnon &:Wilson,Inc.,
Geologic..!Consultants,in the Corps of Engineers,1979,
Supplemental Feasibility Report an the Southcentral Railbelt
Area,Alask..;Upper Susitna River Buin,Hydroelectric
Power and relilted purposes.
Anon,(1975)Southcentral R.ailbelt Areil AI,nka,Upper Susitna
River Basin Interim Feasibility Report.Hydr~lectric Power
and related purposu.Prepared by the Alaska District,-
Corps of Engineers.
Anon.(1915)Subsurface geophysical exploration,pr"Oposed Watana
Damsite on the Susitna River,Alask~:by Oilmes S'Moore.In
the Carps of Ellgineers (1975)Inteilm Feasibility Report on
Ule Southcentral Railbelt Area,Alaskil,Upper Susitna RivH
Basin,Hydroeloctric Power and reldted purposes,
Anon.(1962)Engineering Geology of the Vee Canyon Oamsite:
Bureau of Reclamation unpublished report 37,p.4,
Appendies.
Anon.(1960)U.S.B.R.Report on the feasibllity or hydroelectric
development in the Upper Susitna River Basin,A!il$ka
An::n.\':<'19)ioulfl~."lr ..1 ~.I'Diltll Area Alaska.lIPl:e'~1.111n.1
"Iver 6 ...10 SUQpl eM.t ea'l ilily l\~por:HytlrQ'lrlpI.,,.it
Po""'"''.l"'d rel..teo llu~o.)~.~r~~l"'Itd by 1M'.~.f"l-It.a r.i~:I'IC:\
<Of'1)S Clf UtQ.t,,,e.,....
C"DDS,i.A.t1HO)"GK09)of Ihe Atnlo.oI n111r-;:ad "1:;,;1.:11.
U.i G.S.BlJill!!t-n 007
Csejley,B.Jr.,W".'~r,;'tln ~l.Jones.N.l ~ilJ)el"'inQ,R.M.
Oean,M.S.Morr'<;,f·'.A u!1~f'!I~rf!.1 G.3m:lh .•"'ll 1.1 L
~.lbl!:'rlT\.l"(HHtJ I Recu{;:\.,""'fI".ljt8U1QO.l:"1'1'0 ."rl ;1-0·
.:hOnmoqV,.....cclr[]:,",ts.OW'IJ.,no"U".e""Pdf(('If Ar",f'\g~~
Q.iCld.bid ~~u1"''''''lot co"re,'01 t1l1!illly oBIOrll:\~,".J:...UK •.
U.SG_;Ope""f".tt Ro:po~t 78·:58-A.
Fern..r~,O.J.,Jr.,R,K.[ho-UDQ"f'iilllr~,and G,W.Greene (1969)
f'~'-rilorr.:so~H and r~laled IIrJIlHttld"Q p"Obll'lmfo in Alaska.
U S,O ..".ofessl~rr,ll Paper 61"1t.
Fo:I ..nar~,O.J and Nlet1Ol~,Donald R.(1965)Re)L.irre gf
Quaternary G~lcgy of Ihe Cepowr Rl\l,.r Ba:;1l1.III G!..ldf'tmc"
to the QUdtilrl'1,lry GiIOlOUY .Jf Cl'nlrl!arlld Sou.'~·C.nlrar
Al4sl.a,G"ic!ebGOk tOl NQUA Field C~Or"rl:!l\(e I'Troy L.
Pewe Editor.
,.,,,.I'I,I.»OI"!,ln,R.,...10 11 ~.·.~nor.f 'I!,l"r·.li"'i....ry ""'POr:0"
Ute "!';Cr"l;ic-;y or !'lIt IJ ge.Scd Utevil ,-tiny ('~Wa:Jna
d.lt"'.slt~s.~",trLl HIVf"",A.!,u"a.'.1 '''r,.C:WI"<:'"gtncers.
31!...uppIR!tlcn:,,1 fc,;;sit:l.lly I\"oo,'t on !he Sc;<l.~"n-"~"~l
R,llbeh A~Al.a·,k;l.UQne"SU)ltn..-qlver B".,tn.H~drtl·
el~c.t ric Pe...er and t"l)'loled {lur"csi.'s.
/\
Kach~oorian,R.,O.Hopkins,and D.Nichols (1954)Prelimin~ry
report ot geolOQic hcton dhcting highway construc.tion in
Ihe are.blttween Ihe Susitn.and Mac.l.ren Rivers,Alaska.
U.S.G.S.Open-File Report 54-1)7.
Kachadoorian,R.,T.Pe....e (1955)Engineering geology of the
southern halt or U'le Mt.H.yes A·5 Quad,Aluk...U.S.G.S.
Open-File Report 55-78,
Kreig,Raymond A.anCl RiChard D.Reger,(1976).PreconSlruction
Terrain Evaluation ror tl'le Trans-Alaskill Pipeline Project;in
Geomorphology and Enginearing,D.R.Co.tu,Ed.Dowden,
Hutchinson and Ros,Inc.,(Wiley),360 pp.
Kreig,Rdymond A.(1977).Terrain Analysis for the Trans-Alaska
Pipeline.Civil Engineering -ASCE,July,1977.
Karlstrom,T.N.V.(1964)QuaUlrn.ry Geology the Kenai low-
lands and Glacial History of the Cook Inlet Region,Alask•.
U.S.C.S.Professional Paper <l43.
Miller,J.M.,A.E.Belon,l.O.G~ney,and L.H.Shapire (1915)
A look at Alaskilln resources with L.ndUI data.Int.Symp.
RemOle Sensing of thoe Environment.,Pt"OCeltdings,No.10,
vol.z.p.879-883.
Pewe,T.L.(1975)QUilternary Geology of Aluka U.S.G.S.Prof.
paper 835.
Pewe,T.l.(Ed.)(1965)INQUA Conrerence guidebook to centrilll
~nd Soulhcentral A!iI~ka VII Congrus of the Internlltional
Association for Quaternillry Reuarch,p.141.
Rieger,S.,0.8.SchoephorSler,and C,E.Furbush (1979)
Exploratory Soil Survey of Alask...Soil Conservation Servic.e
Repor!.
Steele,W.C.and J.R.leCompte (1978)Map Showing interpretation
of L.mdsat imdgery of the Talke-etna Mountains Quadrangle,
Alask•.U.S.C.S.Open-File Report 78-558-0.
Wahrhaftig,Clyde (1958)Quaternilry and Engineering Geoclogy in
the Central P.r(o(the Alaska Range.U.5.G.S.Protessional
Paper 293.
-
L
\IPDW 'I!I--_A_L_AS_K_A_PO_W_E_R_A_U_T_HO_R_I_TY----j
flUnlO JI SUSITNA HYDROELECTRIC PROJECT
eU.TABK 15.011
PHOTO INTERPRETATION
1\
/\
/\
DA.TE
/\
RieVI$lOHJ.
SUMMARY REPORT
~•."OCTOBER 19BI I,m,~i}~w ••••,..I...·'·.~
Rail CO ..'ull....n!.I..C
CH.1lPf>.1'1'9.~"O'IC'052502 s"nT III o~11I1 17\
TERRAIN
UNIT
SYMBOL
BlCU
TERRAIN
UNIT
NAME
Unwe.th.r.a,
conJolid3led
bedrock,
TOPOGRAPHY
AND AREAL
DISTRIBUTION
Cllrh in rive,.cilInyon rounded
knobs on broad vilIlley floor .nd
mounLllin peaks.
SOIL
STRATIGRAPHY
SLOPE
CLASSI-
FICATION
Mod,r.te to Neu'-
Vertlcill
PROBABLE
UNIFIED
SOIL TYPES
DRAINAGE
AND
PERMEABILITY
IN UNFROZEN
SOILS
EROSION
POTENTIAL
Low
GR(
WA
TA
C
CI Landslide deposits
Predomin.ntly fOund .1 the billse
of st..per bedrock slopes IS Anguli"frcsl cricked,blOCks of
coalescing cones Ind f.ns .nd rock,lome silt ..nd $II1'ld.
rock Ol,ci.r.
Moderate to Steep
Moderate to Steep
GP,GW,eM
SW,3M
GM,SM,ML
Good/High
Poor/Low Hign ShAllow
Cs-f
FfO
Fp
Fpt
GFo
GF,
SOlifluction deposits
Grilnul.r .Huvilll
I,n
Floodplain deposits
R.,ut...."y smooth to I.b.te topo-
gr.phy (rUled by the flow of
mlt.ri.ls subjected to frequent
fre.z./th.llw cycl.s.
Low cone sh.ped deposit~formKl
where niOn grlldlenl ~lrlam~flow
onl0 Uet surtace~.
Flat plains,slightly .DOve .and
adjacent to the pres.nt Su~itn"
Rlv.r Ind ih mljor trlbut"..les.
Fl.l surhc.r.mnants of form.r
floodplaIn d.posin Isolated .bove
prese"l rloodplilln.
Bottom,of U-sh.ped t ..lbut.ry
v.ltays and Idjacent to Susltlla
• r ••.
Rounded to sh.rp crested sinuous
ridges in upper Susitn••r ...
Silty und .nd undy sill showing
contorted layering.
Rounded cobbles lind grevel with
s.nd and SOffle ~111,~",e sorting
end I'ylrino of materi.h,
Rounded cobbles,grevel end sand
sorted end Iilyered.'With or
without silt cover.
Rounded cobbles,gr.vel and und
wllh some silt covered by a Ihln
slit Ilye,.,.Sorted .nd l.yar&d.
Rounded &striated cobbles,
or.avel .nd s.nd,crudely so..t,d
.lind I.yer-ed .
Round.d ~Irl.ted cobbles,
Qr.vel,.nd sand.Crud.tv to
w.1t sorted and I.yered.
Gently to Steeping
Sloping
Moderate
,clal to Gentle
Flal to Gentle
Sleep Local Slopes
SW,SM,ML.
GVo',SW
GW GP SW
SP:SM'
GW,GP,SW,
SP,SM,ML
GW,SW
GW,SW
Fro:e"
Good/High
Good/High
Good/High
Good/High
GOOd/High
High
Modl!rale
High
Low
Mode ..",te
Moderate
Shallow
She
Very
Shalla,"
GFk Rounded to
hummocky hili •.
RoundeC &striat.ed
gr.v.I,Ind sand.
sort.d and layared.
CObbl,s,
Crud.ly Steep Local Slopes GW,SW Good/High Moderate 0,
Gta
Trlbulary v.lI.y ,Id.w.lI.and
vllIly bottoms In g.ner.I,
betw.en Tlulen,Ind D••dm.n
Cr••k hummocky roiling sur-f.cI,
num.rous Channels.
RoundeCS .nd stri.lad cobbles,
gr.vel,.nd SAnd,no so..tlng or
lAyering.Boulder-cobb)e lAg
cov.rlng ,urface.
Gentll':to Steep GW,GM,sw,
SM
Moder.le/Moderate Moderale Shill/O,,-
Madera'
Gtb-f Bottoml'
v.lleys
.Iopes
0',nO
lArger U-ShApKl
.dJ.cent gentle
Gravely silty .und And gr.vely
sandy ,lit;no IAyerinQ or sort-
Ing;coDble.and bould41rs poorly
rounded ,no stri.t.d.
Genlle to Sleep GM,SM,ML Frozen Moderate
o
L-f
_L_
Gtb-f
Qtl.Gtb-f
C.-f
Gta·
Cll-f
Fpt
C.-f
BlCU
Gtb-f
BlCU
Gta
BlCU
Llcuurln.s
(froun)
LAcustrln.
sediment.ave,.
IIbl.tlon 1111
LacustrIne
deposits over
bani till
Solifluction
deposits (froun)
over b.ul till
(frozen)
Solifluction
deposits «(I"01'en)
ov.r eblation
till
Solifluction
deposit.(frozen)
over terr.ce
ndllTltl~
SollfluCllon
d.poslts (t..oun)
ov.r b4Idrock
Frozen b•.1II1 till
over bedrock
AblatIon WI o ....r
un-W'••thered
b.drock
Colluvium o....r
bedrock and
b«trock
••po,ure'
In l'Wlt.S b,elwe.n ,m.1I .....s on
lowllnd.and In hlQh ellvltlon
bedrOCk .r....FIAt surf.c.to
st.pUke tlrr-ACIS.
lowl"nd.(below 3000')fl.1 sur-
face in the Tyon.O.heln"
River .rea.
Gently roiling to numrne>eky
f.ce surrounding Butte l.lIke
Lowl.nds,(below 3000')between
Stephan l.ke Ind Wat.n&Creek,
and .)((.ndlng upstr.am pa.t lhe
Tyone Riv.r,
Smooth to lobat..tepllke tope·
grlphy on g.ntle slopu 1I1)ove Ihe
progtaclll lake level,we.I at
Tsusenl Cr..k.
SmooH'I (0 lob.te And hummocky
topoor.phy .Iong Oeadmen
Creek
Smooth to lobllte flows of froun
fIne g ...ln.d milterillls,found on
te,.rece of the Susltna,freQuent
belw..n th.Tyone lind Osh.tnll
Rive,...
Smoo'h to lob.l..1.pllke topo-
gr.phy on the flank.of lome
mount.ln.,north and south Of the
Devil Cenyon ar.,.
Hummocky roiling 'uriace
trln,itlon.1 to higher-mounWJ"Q.a
.dJacent 10 Oe.dm.n Cr.ek.
Hlgh.r ele....tlon mounUln are••
Ind lteep slop.s liang the
Susltna River and It.major
trlbuterle•.
O.composed lind undecomposed
crg.nic m.terJal wJth some silt.
Silndy .ilt And silty und with
occasion,I pebbles,to gr.velly
sand.Ofl.n ,0rUid .nd I.yered.
Str.tified undy silt and silty
sand ave·"unsorted silty Sllndy
grlvel.
Well sorted ~Ilty sand .nd undy
~II(overlying blS.l till.
Unsort.d gr.v.ls,und."slit.
with thin Ice layers,contorted
soli Ilyerlng.
Silty,undy,gravel end ~Uty
grevely und .howlng contortad
I.yerlng.
Silty,und end sandy slit show-
Ing contort.d Illyering over oentle
sorted end layered rounded
cobbles,gravel and s.nd.
Mixed O"I".ls sand..nd slits
with thin lc.layers .nd hint
contort.d soli l.y.rlnQ ov.r
bedrock..
Rounded lind .triat.d cob!)lel,
g~...el .nd lall1d,no ,orting or
l.yerlnQ,ave..bedrock.
AngulAr blOCks of rock wllh .ome
sand and silt ov.rlylng bedrock.
Fillt
Gentle to Moderate
Gentle 10 Moderale
Moderale to Steep
Modena to Steep
C.ntl.
Moderete to Steeo
Gentle to Steep
Steep to
Ne.r V.rtic.1
PT,OL
SP.SW,Ml
SP,5W,ML
CW,GM,SW,SM
SP,$\11,ML.
SM,SM,ML
GM,SM,ML
G\lI,SW
GM,SM
~cw,SP,SW
SP,SM,ML
CW.GM
SW SM,ML
b.drock
~bedrock
GW,GM,
SW.SM
bedrock
GP,GW,GM,
~."'.-0<"
Poor/Moderllte to High
Frozen
Poor/Moderate
Lacustrlne-GOOd/GOOO
aaul Till-Frozen
Fr-ozen
Frozen
Frozen
Frozen
Frozen
Good/HIQh
Good/low to HIQh
Low
High
MOderale
Lllcustrine-HIgh
BUI+I Till-Moderate
Moderate
Moderate
High
Moderate
AtS
5hi
MOder.,
S~...lIow
Sh.llow I
to Deep
Sh.llow
Sh.llow
Sh~1I0"'"
Moderat
CIriW+BllW
Collu"lum
w••th.red,pOOrly
consolld.ted
b,edrock
Sm.ll cliffs cut Into
non-m.rln.ledl,.,..nts
Wat.n.C,...k .nd
volcanics In Fog Cr..k.
t.rtl.ry A,nguler ..ubbl.with sIlt .nd sand
.Iong ov.r poorly c-onsolld.t.d sand
tertIary over poorly consolld.ted or highly
w..ther-ed bedr"Ock.
Steep to
Nur VerticilI
CM,SM,Ml,
Cw,SW
TERRAIN UNIT PROPERTIES AND ENGINEERING INTERPRET ATIONS
ROSION
ITENTIAL
High
High
Moderate
High
Lo ...·
Mcder~te
Moderate
Moderate
Moder-olte
LOw
High
Moderate
strine-High
J Till-Moderate
Moderolte
Mod~rate
High
Moder.le
ler..te to High
GROUND
WATER
TABLE
Deep
Deep
5"0I1iow (perched)
Shallow 'perched)
Shallow
Ve ..y Shallow
Deep
Sh•.r!ow (0 Delep
Deep
Deep
Shallow to
Moder.tely deep
Sh.llaw (perched)
to Deep
At Surfilce
Shallow (perched)
ModerAtely dMP
Sh.llow (perched)
S".lIow (perched)
10 Deep
Sh..llow (perched)
to De.p
Sh..lIow (perched)
Shillow to
Moder.tely d_p
Deep
Deep
PROBABLE
PERMAFROST
DISTRIBUTION
Spo,..~lc It low
ElevalJol1.
Discontinuous at
High El.vations
Active -Unfrozen
Inactive -Sporadic
Discontinuous to
C(lntinuous
Unfrozen
Unfrozen
Unfrozen
Unfrozen
Unfrozen
Unfr-ozen
Unfrozen 10 Spor..dic
Ou,contl"uous to
Continuous
DI~contlnuous
Olf,continuou~to
Continuous
Spondlc
l lpar-.die
Oiscontlnuous
Gtb-r Ollcon-
tlnUOUS to Can-
""'
Olscontinuous to
Continuous
Discontinuous to
Continuous
Disconlinuous
Discontinuous
Oiseontinuous to
Continuous
Spar.dlc
Spor.dic
Sporadic to
Oi,contlnuous
FROST
HEAVE
POTENTIAL
Nil
LOw to High
High
High
Low
Generally low (High
for surface cover)
Gene"ally Lo....·(HiQl'1
for lurface c:over
Low
Low
Low
High
High
Moder"le to High
High
High
High
High
High
High
Low to High
low to High
THAW
SETTLEMENT
POTENTIAL
Nil
Higt'l
Low
Low
Low
Low
Low
Low
low to Moder.te
High
High
High
Moderlle to High
High
High
High
High
High
High
low to Moder..te
BEARING
STRENGTH
Very High
Low
High
High
Surficial Silt,
Low,Sand'
.Ind Gr"vel,
High
High
.-,Ig"
High
High
ModerUe to High
Low If Thlwed.
High when frozen
Very Low
low whe"
n"wed.
High wh.n
Frozen
low If Thflwed.
High wh.n
Frozfln
Low If Th.wed.
High when frozen
Low wh.n
Tholw.d.
High ....h.n
Frozen
low If Th.....ed.
....Igh whln frozl"
High when
Froz.n.low
wh.n Th.w.d.
High
low If Th.wed.
High wh.n F roz.n
lOW If T h.wed
High when Frozen
Low to Very
High
Low to Moder.Ite
SLOPE
STABILITY
Low
Low
High
High
La....·to Mode"lta
LOW to High
Moder-ate
LOw
Low
Low
Low
Low
Low
Low
Low
low-
Mod.rflte
SUITABILITY
AS SOURCE
OF BORROW
FIne'Poor
C~,.,.-Good
Fine -Poor
Co.,...•Verlable
FIn••Poor
Coe..,••Good
Fine'Poor
Coa",••Good
"lna •Poor
Co.,.•.••Good
Fine -Poor
Co...,••El(callent
Fine -Poor
CO.".e -Excellent
Fine -pggr
COAru -[xc_lIe"t
Fin.-Pgg,.
Coar.e -F.I,.
Fin.-1".1,.
Co.r••-Poor
""
Poo,
FI"e -Poor
Co.r.e·Fell"
Poo'
Fin.-Poor
Co.,.••-Good
Fin.-Poo"
Coar.e -Felr
Fin.-Poor
Co.,.••-Felr
Fin.-Poo,.
C04I,....Poor
L
,
TATIONS
/\
/\
IIPDI~1!I----=A=LA=S::-:-K_A~P:::-:O=W:-:-ER=A:-::U T:-:H=O~R:-:::IT'::"'"Y--tRUn0.11 SUSITNA H YDIIO[LECTIIIC PIIOJECT
I~,\ra~fr;.\IA1I-:_"_._;,;,;··;,;,;·c.:ll:....;.;";,;,;II'---lI..~u;';;;;'=.------..;;;:i
1/~'\JL..f---.-.10"0 NO.,.,'
l---CO=-=."TE:--I'",,=-'.\----------=•.,;'.""1:::''''''=.----------1":0<:-:.+_.,,-1.f-:_=f.••M CXJINaLTAN'T"!J...":I......,.0••101 T 11M 1/\
L
[j~ALASKA POWER AUTHOR ITY~U~[O 1---,s"U-,S"'=T""N-=-A-H=Y=O-=R-=O-=Ec:-L-:E"C'"'T=-R=-'--:Cc:--:P:-:R:-:O"J:-:E'"'C:-:T=----j
BUBTASK !5.D2
PHOTO INTERPRETATION
f--------+7rl--------------t-+-I----lTERRAIN UNIT INDEX MAP
Bedrock
Mapplflq
Units
Tv Tsu -Tbqd Tsmq TKqr Jom (Jtr)(Jqd)liv Pzv (Pts)Kaq
Abbreviated
Descriptions
T~"'IJllry Vtlll,....,.\
roc,,~:•.rull!)....
ifltru~jve~_flews,
il'1d pyr.::claHlcr.;
rn'to!llllic to t ..~",II~c.
;~I'\\ar'y nIH'l-rr:\rlll~
~.O,I'fl.lI"l'''''Y f'O(l<.~:
C'('t""9'ClI'I'lIlf,U.,',1ltd"
f10'"t',IIIUJ ...loIyH nt:.
1 "n'<lry 1)1-0'.!~I i .-\.~-y ~,",'I.
;'''51'101;1'0''-'1_;«oil'"".;1","1 'tt aro;1 9r.,_,
t"lOl""t1tllotllQe Ii'.'or,.~.r;t1""~"ltl''''';1 I".·QU'
(·t10d J.llf ..larqe 'Uak.
ttl-".-y "n,'('If
C ...f1I .........go,.j \1'.'11 1;-='31
101""1'<1..;;~-4I11 j:ILj:l p',
'..roll 1:10 "~ol'nlln If!i"1
1 III 'II,.r ~"lin·
....h,~;..~hl.:.'
, r 11:11..,ltr (tr .~"~
Llr",r.,..\;11
-,,,....:l.l,,-,>I
r...tl>"ol.4lr"'\~C:"''\
,r11.ut I J 10i0
.""...llKltQ-C 010 ,",('"I ;;;;'r'·~~·W;;OLJ .rOlH I"
_nQ ,"Cl.",qllE:..:..-.1I11 'iii""'"1<.,o(
'"'OLI:....MO;.""(:ro;ll.r..:llll'Ot d.'.;lI"'1l1......
1<Ii ..rt1"L~'OT"'."M'r hl7'rllf'lilt:"ill ·
"1~1 IOw,.r ..oo ,".I ..rtIQ..p",~",
rrlelll[
:l1'1:t '\loll
,nlt'rn.t
not",e
Miscellaneous Map Symbolg
Scarp ~Slide scar;<\1T Buried Channel ~Trail
D"U APRIL 1981
L-f 10."'1;<'1(1"'"1"5
d'-Ql_"l
L .'o,.J~1 rll1~
GiQ ,.0'"'ll!>0 ....,-
..tJllHiQ'n lill
L ....l..u~lr .,..
dt'llXl.lt~O"lI!r
Gtb-f :luU!litt \tr(.,IIn)
Cs-f
SoUfh.lnloro
depOSita (f'"97f'"j
Gtb-f ove-"t>-/I~.l till
~rpou,,)
Cs-f ~hh......w'Jl\
C!.Dpo:S "(fr-o.unl
Gf(J Ov......ftf,llIO",,,,
Cs-f
5--::1 !i.t-\ltWl
'Ilep<lllu (fru.ter)
FPT ')Ve";.''-&1;_
3lIt.l1,m_"""
Cs-f ,;Kl.IIPI.;.t.Ht:n
<lI~:JOI-·'~('•••1 0 ',l3"Xu"o....e·~tlrl'lck
Gtb-f F--Ql'e"~...,.I lill
13XU (.>v"r to4';1-.;:c"
AW&!.lIIr'1111l
Gta 0 ..."'''un"s-;;:u ."",..,-eel
be4rt:<:k
CD hlV ~,gVllr
C +B d.-oCl<..,ndBXUXU~c!lJ"o.:..-k
"-:pe'IVrt-"
sS+Bxw
Cl:llluvhJ.....(lvfll'
w"...Ult"~..d .
par;lrl.,.l:~l~J"
dillied n~'l)C;1l
Terrain Terrain
Unit Unit
Symbol Name
Un.....ea··H'.:red,
Bxu cunsolidated
bedrock
C Colluvial depo!io;ls.
CI l ..ndsliCl~
Cs-f 501;11u:~.:...
deposits (r'"JZI!I"I)
Ffg Grdnul.lr alluvial'.n
Fp Floodpl..in
deposit~
Fpt TerraeI'!
GFo Outwash deposit,:
GFe Esker (jfOPOf,ll ~
GFk k.'jl*Cepo'l~'
Gta AtI,.thon ,ill
Gtb-f ~..s.",(lr::l'ftt)
0 (h"an :,'tJ(lraih
SUBTASK 5.02
PHOTO INTERPRETATION
TERRAIN UNIT MAPS
[-APm~II--_A_L_A_SK_A_P_O--:-W::-E R-::-::-:-:A-::-U."--T_H",,,O---,RI,-::-T'---Y-I
MUn[O SUSITNA HYDROELECTRIC PROJECT
O~~~2~O~O~O__4~OO.O FEET
SCALE
RVS
Trl""IIC ."....{;,U.Ultlt
;i'Ul 111t·...."u,
II ,,,,.t>,,,I1~"O'~h~ll(,lw
",..,."lv ~'··UJ"IV:l!
Kaq
.,y,.;.~u~.I·gll,,~
;3t".¥'.,L ...,:,r ~
..dp'.,t"llIIll
,;Ow,-&t)".....r.-.
I~U.Mo'lillf"'rQr~n;.m
/
---'/
Rock Contact -./Buried Channel ~Trail///
Bedrock
Moppinq
Units
'.,..r~~"'~.T,.."T:'~~HI..,T:~~I~~.."~~~rAbbreviatedIoUOt""I DI·'"lHbnUI:."0[""~..l.l••!J -,,I..dol ..'f'\-.
/-,--D""e_s_c_r""iP_I_i_o_n_s-..JL.-'--;_:,._··_'_.'_.u_:~_:._~_~.._:,._·._..J-~~_n_':_.,_,·"""__·_·_n_'._,_"_,.--l._~_,o_~_':_:_~ll!_'~_'_":_._'''_'I:'~"''''0 '"ill
Miscellaneous Map Symbols
Scarp ~Slide Scar ,<\l'
OAT(APRIL 1981
~"'OJICT 052502
Terrain Terrain
Unit Unit
Symbol Name
Un.....ttl.l"'..a,
Bxu cOI"llOlldated
b.-dl"OCk
C Colluvial depoalu
CI Laneullct.
Cs-f Sollnuctlon
d.,po,lla (tl"'O"")
Ffg C,...,ula,..Iluvl~
r...
Fp FloodplaIn
deposIts
Fpt T.,.,.Ka
GFo OutwaiUl d.po.I~
GFe Esk.,.deposits
GFk K.me deposits
Gta ....bl.tlon till
Gtb-f S.ul till (frozen)
0 Org.nic daposits
SUBTASK 5.02
L-f Lacustrine,
(fronn)
----I...-lacustrine
sediments ov.,.Gta ablation till
Gtt-f
Lacultl"'lna
dapollu ov.,.
0 ...1 till (frozen)
Cs-f '
Solifluction
deposits (froan)
Gtb-f ov.,.b •••1 tIll
(froun)
Cs-f SolIfluction
deposita (fr-o.zan)
GiCI ov.,..elilion
till
Cs-f Solifluction
dapoIIU ('!"Onn)
FPi""ov.,.t.rrace
sedlmentl
~Solifluction
aapo,its (frolen)
XU ov.,.bedrock
Gd b -f Frozen DaW'till
XU ov.,.biKt.-.:ICk
Anl.tion till
~ov.,.un-
w ..th."d
bedrock
Colluvium ove,.,
tfxu+BxU bedrock .nd
bedrock
aKposure,
~+BXW Colluvium aver
w••thered CU"
poorly consoll-
datMi bedrock
PHOTO INTERPRETATION
TERRAIN UNIT MAPS
I ar..O._lPJI--_A_L_A_S_K_A_P_O_W_E_R_A_U_T_H_O_R_I_T_Y_-t
LltUn[O SUSITNA HYDROELECTRIC PROJECT
R"f\'lIIO"'S
2000 ~OO FEETo
SCALE
.".
Bedrock
Moppinq
Units
Abbreviated
Descriptions
Tv Tsu -Tbqd Tsmq TKqr Jom (Jtr )(Jqd)RV Pzv (Pis)Koq
-epu..,v ~'Q't:•.,,~TI',"t ..ry no,.-m..nru .....rtl...y tl!01'\4 ~."1I.ry .C:.,.i1.Tj·rll."~·.an4 (or JL.:-"'oIl.~.t .'IT:JHI ut~,"~"~IL G~j,1:-l.:..1:..It...tc 0".1 I.t (,'"~la ''"\0''.,-""!:It""J:~'tlw tl'dl"...nlltr y ~"''';Q'/l.o<.l!onlt'_l~,l I"~lnr ""(,Inr."I'!',...T'?I~"",·9"~'"·-s ~~1~~n"':r~:bf.~;lIfl~••n ..;av'fr.;"'''.0<:....,e".04'~I,e "',1\.1-1t'1(l'1,.........r-•.0',.n"",l',l~U~>vl!!~"QAt.:-:>"U'O<\IOf',1l1':...ntl-~M",DI"l"'Jo:gr,,<t;)('jl ,"'.p..."••f,-r,r·W ,no ""'"f"""-",I1'C .Pl.1 flllt!)!"'I.lol"lt",~;~'Hl -Ow ~O·f."'::'.~<r;;clo<s,'"acol;,M"(1 ",,<':tIC:
..no ..Dyr"(.'tJ.5l,o;-"'H~n".'""(.1"\H~n ..rnO
"
ei\.,....;"~Iock.·"O"'.cl'41"',:e ~.:.'.II'<,:!'ttl•c'1V,.....""",unt .10U,1 ",411111 1Y11l,IQTH.:I'JI'u(llt,·."J.lu."t..,
"'n~l:Illh:'0 nll,,~lli;;';'·,I.!#.J,.:!rrt...(Jg.u,.('1"1").1ll~."1 ""i"mnr;:."'·'rn
Miscellaneous Map Symbols
Scarp ~Slide Scar ;(\1'~/
Buried Channel ~Trail .~///
Rock Conlacl r~/
Terrain
Unit
Symbal
Terrain
Unit
Name
Bxu
Un ....e ..thtred,
consolid ..ted
be<j roc k
C Colluviall depo~lts
,
Abi<ll,on till
ovc"un'
....':"'th'''....:1
bedr"~'"
Frozen basal till
aver beorock
Or".nic decosits
Granul»,.alluvi.-'
t.n
LaCl"jJ\~,r,e5
(Irozen)
501lfluctton
d.posils (froz.en)
over bas,,1 till
(frozen)
Latust,.'ne
se~Ir'r,ents over
ablation lill
Lacustrine
d~oosLIS over
basAl till (froz.en)
COlluvium over
..'todlher",d or
po:>dy tonsoli-
d.,te-d bedrock
SOlif'lJClion
deoposil:i (frozen)
over abldtion
till
Solifluction
deposits (frozen)
aver terrace
sediments
~Iluv,um over
bedrock af'ld
bedrock
e'~o:,ures
.,,,~~.u·
depo~·.IS (r"'Hen)
over b~,,::;;"k
Baul till (frozen)
Floodpl..in
dliposiis
l.llndstide
Terr'-CIJ
Out....ash deposih
SOlifluction
deposiu (froun)
GFk
CI
GFe
Cs-f
F""P""l
Cs-f
GiO
Cs'f
BXiJ
Gta
GFo
L-f
°
Fpt
L
GiO
Fp
Cs-f
Ffg
Gtb-f
tlXiJ
L
Gtb-f
Cs-f
Gtb-f
Gtb-f
tfxu+Bxu
SUBTABt(5.02
P.MOTO INTERPRETATION
TERRAIN UNIT MAPS
[A PD(.~I---::A::ccL:-:::A S::ccK,-A---:-:-:c-:P:-::-OW:-::E-::R:-:-::-:Ac:-:UT-,H:-::-O::-:R::-:IT:-::-Y-----jflUn0SUSITt-4A HYDROELECTRIC PROJECT
2000 4000 FEET------=ao
ESCALE
DAH
n:::tn..!<lOlilwil
'*l.J ~..to:II"
,,'..~tl·Jd~~_~.q~'
,-".,S""ll.'·'Cr.
RVSKaq
~'J'S .":111-1.
u'.y .....o<o.u'..
\Otl('r-m~'.l
10'1_"',:_.r'1~lL
'.el,.'"Clt.f'OlC·;"'."'
Bedrock
Moppinq
Units
Abbreviated
Descriptions
Tv TSiJ -Tbqd Tsmq TKqr Jam (JtrJ(Jqd)RV Pzv (PIs)Koq
T ..rt.",.y VOI':;ilII "j r~\i ""'C""I'T',lrll'"jer'Jl,r."niOllte ':"ar'"llry .t::...·r.t.re",'y .''''l(:/Q'',"'I'~~~'C <l.Ilj"lllloel·\e rr 11:0"''''b.$"'lIC ~..t"'"110010.1;~N\lllIc Cre'dCob..s M:;Jlllll_irl~ulI
"ock,,h.llo...~.t~.m.·ll.Rf ~rcx.fo,\:O"··,adIDr,[u ",(1 m'"mAllll'.·0 ;,..n·t.,:,..,...;:.o"'i grll1ll1{s Illu~,II """r~,,"·..·."vl~".-,...;ron11-e ~I~-"'t'Ifl Q··a:y ...ll;;:L.....",......~,I.
•....V\'S;VIU.'10....'1,cOOQ,(Jl'"'itltr,iltl :l"(l~-Ql"l"Il:r<1~"d..~!rill't-'J IID-~I t ',;p1"t~t"ll1"''Ol ,.,ru.;f r"rm'''':,"1;11'Ulilt~"'"¥J,U •....Cl ~,.t;....,..t2
"
".'"vOIl;....IXjl."'C re<:"J.1111(10.....c1g...",.,.;,Iller".:
~"l)vr«'!lIosttl ~;'tll;J~·C.MI~~'ll~'tune \tl"'~}.of .,,""~.,t.oco<,II"OlU]I(!.""te It,...•.no nlnn"..'"."C~"""\"".,t1'ltIl,,-!,m otllon c turbld'lf ,.g".nt:.m..,.n"
rh"ul,lll."l\.~llof·lr .\Jr-1)11OQt!:"'I.''WU ~.....,..I:>.....!]"-.d.I'l'llt"-;(l'rh.!lm
Miscellaneous Map Symbols
Scarp ~Slide scar,<\1T
/./~7 ~/Buried Channel ~~Trail /'
I_pow li--_A_L_A_S_K_A__P_O_W_E_R_A_U_T_H_O_R_'_T_Y_-i
HUn[O SUSITNA HYDROELECTRIC PROJECT
Terrain Te rra in
Unit Unit
Symbol Nome
Unwe<Jthl"red,
Bxu consoliddted
bedrOCk
C ("ollu"'.<I ....:o.:posits
CI Land~lide
Cs-f ~.:.f uction
depc:..a «roan)
Ffg Granul..,.all ....",ial
r.n
Fp Flc:::dpl",in
depo,>lt ..
Fpt Terrace
GFo Outwash deposits
GFe E.sker llr;lJo~ts
GFk Kame depos.ts
Gta AbLiI\<m1 I,ll
Gtb-f Basill till ""oan)
°O"g..nic deposits
Kaq Jivs
L-f
L
Gtb-f
Cs-f
Gtb-f
Cs-f
GtO
Cs-f
F"P"I
Gtb-f
l3XU
C +B-gxu XU
~+Bxw
1.1l~U!Hr·f1~
(rrozen)
La:CuHrtrH!
Sl.'rlJrtMI....'s over
..blQtI'lf(,lill
L ..custrint
dt>POIU ~~\Ie~
b.au!t'(f~lllen)
SOlifluction
deposits (frozen)
over baul till
_(froze;")
SOlJflu":lion
deposits (rrozen)
0"."abbllon
lill
sallfll:ction
deposits.(frozen)
over terrilce
sedimen\:l,
~lIn Ltion
dlllpoaSI\S 'f ozen)
ov.r bedroCk
Fn;.j'..n ItU U.
Ovll"[}~"'Q(;K
,Q.OIIl:II.<I;ti
;I"er~
.....II'fI':'...d
11C-:;In;Jol;;W.
Q'!,",,,,.U'"0 .....
wa~k ...,.~
t;eUroc:k.
CIllIlIol",lu!',over
wf',I''''er"a or
poorly ~c'~'t;)li
dated bad..ock
L
:*t.~arQlll1le"
QI'.Iy>V.ckt<,0'a
~!:I1,1t!
Illfn.JCQuent.c.
lraClIIj!~t ..marl/"I.",
-,·.1I1'C'me,rr~lo)••11
at1d :tl ..\e.4n
,··tRrl.<!13'detl ~Mllll .....
",."n.tlllfjUI!'I"'"
o~~~2~o5o~Oiiliiiiiiiii~4~O!O.OFEETSCALEI.,SUBTASK 5.02
PHOTO INTERPRETATION
TERRAIN UNIT MAPS
/\
Cs-f
"""Gitrl"
Bedrock
Mopping
Unils
Abbreviated
Descriptions
Tv
T.-l"·,_'"
"..t'I'"
'I I"LI~v"".101"".
..~'·~.1\-='
I'tt'\'(!lL t~H"'~."f
Tsu
,t'-";U ~
·.1''''''1I'T")'1'0":'"
al"'.'JIQI"I\.oo'.I~.,,.nlj.
,,1'."L .•.•u _1".1>:~ne.
Tbgd
....!~~I'h~··l.
Qr,O'lQO.1'.,.:'1;0(,.1
hO ..n:tlI.HC..ilr;oll¢Cl ':)1",:
,....,.;:::1).
Tsmg
.~t"ry ~M·,.t,
/f'I'l1l'1ltft If!jI-'a or"'lll
,..."rco':oc/Il f'lU 1t~..:It
1)1 ol .oll..-e )!\)~I(
TKgr
••101r,",/'1"
:'r"'d{""~u'gr.,.,'r~
Ian 101;)~.....,,'10';".
Jam (Jtr)(Jgd)
...r.~J'r..lII'lp":JQ,.:.
I III.I'Il'·"tJt ~r.,,"
.Lt".Il.:.oil'I..;lo.:.J
-'""f"!I.e (t.).r,>
;'-;lno,;J cr,l.Jj,1d i.
RV
r""-.1.-11o
ortt''''r ....
I ..·...oJ II ll'ulll''''
-,~r.""·,J',.....'·r~
Pzv (Pis)
~..I1o ".IC"Or-illu:•
'l:'111 ,-,If .ia.-
,"'"
"",".
Kag
c....:.niH 011"11111 'is
llIr~d1 lC '.a.\""...."'"',1;1'•
1I\1t:1l;J',"",,~
l!Wf'It ,eoq •••r,..
t'I,wl),..ao rrnU~r;:'ll 1m
-,,Hie
and ,WIt.
j,,'(ll!',J,
Miscellaneous Map Symbols
Scarp ~Slide Scar ,<\TT ~/
Buried Channel -$7 Trail ././
/
/~
Rock Contact r~/
Kag
4.OJ1I.'",I.
,.a,"~c....::JT ~
".,.~"Il'lt -'<'-Hi"It"
.,.;I'n'ljoll""l;oq.:I'lam
RVS
Trll,::'II',,'.,fi",~lt
~t.O 41.'",...
II t~rotl~atd 111
'"'"'~,~
SCALE
o 2000 4000 FEET
!
R!:.YISIONi
Terrain Terrain
Unit Unit
S ymbal Name
Hr"Iw."lr~red,
Bxu :cnloc.lid<lled
tjedrOt'k
C r"llu"iAI [!e;lcsH1O
CI Llil',l~lIdc
Cs -f C,nI1tIU<;tiQp
dlllpa..ill lr,.ozen)
Ffg Gr.nul~r oillluvi ..1,.n
Fp Floodpl"in
deposits
Fpt Ttlrr..ce
GFa Out.....sh deposits
GFe Esker u""~o5its
GFk Kame deposIts
Gta Ahrallon till
Gtb-f B.s.!till (f,-oan)
°Oro;...n Y (1"QO.lirs
L-f l ....c:l.ut,.mrs
(r~L.m)
L l<l(;:;sl,'jne
GTO sed'mO!nts over
Iblatmn till
L Lacustrine
Gtb-f deposits over
basal till (frozen)
Cs-f Sohfluction
deposits (trOHn)
Gtb-f ov~...ti ......1 till
(frQ.Ien)
Cs-f SQ4.lll,,1ction
d>':(:Io.ll\(frozen)
Gta Dver ablollion...
Cs-f 5UlltlUCUCln
dll;j..lOS,ts (frozen)
FPt over terrKf:
ledin,.,llls
~...1 uellon
dl'fJO~lts l'renen)Bxu over bedroe"
Gtb-f ~ro.l'"tn-ul till-exu ova","!::i"jrXk
-~Atlt.l!,Dll till
(IVtr un-
wl!!-~Hl"~"'"
t:ti1r;Jl;"
Jfxu+Bxu
c~vw~CV"
bl!Il::lnx:k ....d
~'edrock
e:-ootou"c1I
iw+Bxw
ColIl"lviull'OVIjI'
••..If:.'Itl'..~d ,-
tIOQI I Y _0IU1)1 -
dnl.....i b_T1TTK"
L
I_pow If-_·A_L_A_S_K_A_P_O_W_E_R_A_U_T_H_O_R_I_T_Y_---j
"UmO SUSITNA HYDROELECTRIC PROJECT
SUBTASK 5.02
PHOTO INTERPRETATION
TERRAIN UNIT MAPS
CH.~..,pp
Bedrock
Moppinq
Unils
Abbrevialed
Descriplions
Tv
""~n.~ry 1;'91(.~,(
..~..,U11 lD'"
!':I'.."velO IU';,w,",
•nt.I i'Y"_'oI~"("".
'-h)'l:il til:In bllt.lt.c.
TsiJ -
l"~I,.ry 1'\Or>--"'T\'''~lfW
Ioe:;llfTltl'lC..ry .;~:
to"'~Ic:n""{I\",,.....'10'-
~:r..,,,,.1"0 rl"'i'''fltn~
Tbqd
-..,II .r~O'01,r..
9'~.m::.dI~~llc ,......'
"u..""ll........'Qlt'1.""11
O·
Tsmq
·"rll."y &:~.u.
10"\1"'0111.1 ~.d Q."ld•.
rt-llr...M'I'"'O 11',,,.......1
M a .Il.__110<:".
TKqr
",,"1 "'-y .•n(j10if
"......eavlo <;If.rllt •.:...
form,nQ ""'.111 ~lu:::rU:
Jom (Jlr)(Jqd)
....IT'nfoC "mg",r.,Alol ••
hl\","l!,,,,..,-
..-.".:1 -.rb'.Ioc..'
Iron<1toll"ftotlll_f "tja".<-~,Ju:;nIl,tilll
RV
......II~,t l:.JlI,.j,ll..:
m"'tol"'\1 c:..lIn't'-""...,
IIJ.........~,n 'I':"lIl""
.Inl".,Illl",ret-tl":
Pzv (PIs)
",till -..~"l~
flrt<l .f'le •••II<...1[""
\,l'lIl'"'''O'"'''
Weil .,..1.-hlll·.UOhlt
""j.
Kaq
C ....IA r,J<·'"'"'i::I\:~
,rHI .'.Y"'#!""'.rf ..
L1I1U <~l'fO"".d
tUI"e-.J I.'ealJ.:,..,<....
l.,..~~~1!'...~,1,..t'll ~".
,I"I)'I"
!l'{ltrl'l""
Miscellaneous Map Symbols
Scarp ~Slide Scar ;(\IT ~.~//Buried Channel ~Trail /
/
/-
Rock Contact r~/
~[P if-------:A_L:-::AS----:K----:A---,-,-,-,PO--,,-W,.-::E----:R:-:-=A----:UT----:H--,,-0:-cR-::-:1T_y-------jHUn[~SUSITNA HYDROELECTRIC PROJECT
1\
~Llv,...mo\'.r
b.d~k an,g
tieolko(k
e!"tlosur~s
LaclIsl rl""~
(fro....n)
'sul,f,;"l,;tlon
dllloosits (IrOlen)
ov'ltr lerr"ee
sediments
Abl"th::l'"till
over'"un-
....ol'.lhllor~d
btldroc.k
J':-oz..r to.i~1 till
")v,·~tl'llGmd,
Sollfluttlon
dtogosib (frozen)
o..."r bas...1 till
Ul";.zen)
Ctllluv'um.over
""elltiUt.....a or
pocrly <:C1f1:.oli-
dIlled b!ll1'"'Ptk
L
t.~uHrI/'1e
seOI"'tl·,ts over
Ilbhtion till
La~ustrlne
d.t:jXI!.iu,over
b'l.loliJ lill (frozen)
$cllFll.lUlcn
depcilllS ((rOlen)
QVIIJ'o.e-O;()(;;I<
S(llJfJUl;;t i on
dllll;l.::;~11s ('rozen)
Q.~.r ;It;1111ion
tIll
L-f
J3J([
BXU
L
Gta
Cs-f
FPt
Cs-f
(jj(J
Cs-f
BXU
Gtb-f-exu
Cs-f
Gtb-f
Terrain Terrain
Unit Unit
Symbol Nome
Unweathered,
Bxu consolidated
bedrock
C Colluvial depoJ;its
CI Landslide
Cs-f Solifluction
deposits (frozen)
Ffg Grollnular <llluvi.1
t,n
Fp Floodplain
deposits
Fpt Terrace
GFo Oulw<lsh deposits
GFe Esker o ...pos,ts
GFk Kame deposits
Gta Ablolltion lill
Gtb-f 8"...,~dl (frozen)
°Organic deposits
B~w +Bxw
BUBTASK 5.02
C +B"BXU XU
PHOTO INTERPRETATION
TERRAIN UNIT MAPS
2000 4000 FEET
==::7
o
SCALE
RVS
'·I,n.SH rn"l::ltlJl£.lll
In(l ~I,.l...<111
,r'\I"'f":".ao.::Iri~d \.I,.lIa-....
"""...,...~~..C1I_...!'L.
Kag
jotll'3\a ""-0 \"
";';:,.v ....ol ..l!,ll,r ill
~..'~d
d :.~~':'OlJtlllt:e,
'ilflt:l.l"i1']Ill'\QrPlllIl'tI
FOR CONilNUAT'ON,SEE
Bedrock
Mopping
Units
Abbreviated
Desaiplions
Tv
"fr'\I.ry V~M-,c:
ro..lo5·,.II U ..
.."f'".'Vll~.r 0"",
•"d p"ro:;:::...,10(:1;
""~'U 'l..c.:to b,,,,.lh,,
....~.I-'"It gO',r<111'-'_
..,,':I"T.....t,flr-y ...cu·...
n"'O·Ol"\.r"l~:JII''I'1;1'
..t .,.>d ..,,10101'1"'.
Tbgd
r"'l'a"'y LlllI,t.
IliT't"'o'Jd'lIrt •.I ('Jl'f'
1"''''"rt'4III'-'C't:OIr.-a';Q 1'I
I Ti,..,:}
Tsmg
•w't Ilry ~"',lot .
rrr QI'l";\oI 1411I .rla or:l"'..
....,,-••••,1<1 liP 1"_"DOr
al •".Q~uot.•.
TKgr
,.1'1'~y ""r','~
;;:~,II.Ll!'o ....O·,n'I ~~
'"Ot'rn,'IJ It,.'tl1ulan..
Jam (Jtr)(Jgd)
J,'I",'.'-''''lP'''l'I,t•.
"n,I llr~
~tt t.l ~ml..1::lC.1
,·l:,..~.....'t.I ~II'J ,tJ
p""""•.rlH1r'Ilit ,Q.:I.
RV
t,u"q t
r pl.:_C.III1I:to(•
·".....-rLJ '":Jf'1,,'~'"1'1"..lit .'~V
Pzv (PIs)
.•l.tit ea~l~lt I:..&~•.
~"O ••1J•..1 ,.1.'..u.
"'.,......u .-._.kt..
'f'!"'lIlt ..""":rt,"
'.J.
Kaq
rill.·.·1"!".f"gol (II.n"~~41'"I'kiJ ,.
tlltr"(1~'tlr I
'I tll.'NlII""
'~W91',.o."i1I.-n(.r~,"''"'
Miscellaneous Mop Symbols
Scarp ~Slide Scar ;<\IT
./
Buried Channel d Trail ,-r-./
/
/~
Rock Contact r~/
1\
Lacustrine"
(frozen)
SO'~;uCllon
deposit.."rozen)
ove..at;.lJltlOn
till
Solifluction
deposits ('rozen)
over u~r".CIII
sediments
SOlifluction
deposit!>(frozen)
over bas.i1 till
(frozen)
Colluvium over
weathered or
poorly consoli-
dateCl b('drock
L<lcu$lrine
:l.ed;~lefH"over
ilblOition lill
c~u".'J'"over
bedroCk "nC!
U-edrock
exp<ulur-es
Lacustrine
deposlH over
bilul till (fro;t,en)
Ablation t,lt
over un-
wU nltred
bearotk
SoIl'Iu.ttion
dpPOs""(frozen)
0-......bedrock
Frozen basill lill
over blt<Jrock
GtaBXU
L
~
Cs-f
GiCJ
L-f
Cs-'Y
BXU
Cs-f
FPl
L
Gtb-f
Gtb-f
1JXU
Terrain Terrain
Unit Unit
Symbol Nome
unweathltreCl,
Bxu COI"l$olidated
DeC rOCk
C C:Olluvl$1 deposit"
CI Land:lolid"
Cs-f Sr.llffuction
df!PO~jU (frozen)
Ffg Granular 01 I hJ\I'I;l1
t,n
Fp Floodpl<lin
depOsit"
Fpt Terr.C..
GFa Oulw,n"dl!po~uU
GFe E)k....(Jr.~Qsitl
GFk Kame (fepos.ts
Gta Ablation till
Gtb-f Baul till (frozen)
°Orll""l.(.Cleposiu
SUBTA6K 5.02
tfxu+Bxu
Efxw+Bxw
PHOTO INTERPRETATION
TERRAIN UNIT MAPS
-,
I APDr ~II--------=A-,L-=-A-,-S-,K:-A-----=-c::PO:-:W-:-:-E-c::R:-::-::A-,-U:-:T_H::-:O::-::--R::-1T:-::Y,--------jffUn[O SUSITNA HYDROELECTRIC PROJECT
CH.Al'J>.
2000 4000 FEET=::::a
REVISIONS
o
ISCALE
DATE
RV5
Tn••'l:"·"r.n...~.,\
"'l[I[I.l..\c,llr,
'''ltrn..,Hlc::l ~'1Jllvw
,/tor'"~.l1l.ttl'l.~
Kaq
10l.oi,~rQ Ill:
Q".~"'"k",j"
k OtH.,,,,,,,...:!
~r lot"'~1II ~.
;"'110.""'I<V'lOl'pnl''Il
Kaq
'.•'ll
nl1 •••11
I'l.,-ll~:":
Miscellaneous Mop Symbols
Scarp ~Slide Scar ;(\Tl ~/
Buried Channel Y Trail .~./
/
,r/
Rock Contact r~/
Terrain Terrain
Unit Unit
Symbol Nome
Unweathered,
Bxu c:an:solid"ted
bedrock
C Colluvial depO$its
CI landslrde
Cs-f Solifluction
deposits Uroun)
Ffg Gr,imular alluvial',n
Fp Floodpl"in
deposits
Fpt Terr""ce
GFo Outwiuh deposits
GFe Esker 1..I"'~05;ls
GFk Kame deposits
Gto Ablillt;on till
Glb-f B.s.l Llll (frozen)
----
°OrQanic Clepes;ts
L-f l".cuS!r1nIB
(froun)
L laCUSlrine
Gto sediments over
ab'C1tion lill
L l,n:uslrine
depo!>ih overGi""b-f bas",'till (fro~en)
Cs-f Solinuclion
dePQsits (lroan)
Gtb-f over DasOil till
«(rolen)
Cs-f Solifluction
depos,ts (frozen)
GtO over <lbl...tian
till--
Cs-f Solifluction
deposits (froun)
FPt over terrace
sediments
Cs'f Son.Kllon
BXU dllposits (frozen)
o-....er bedrock
Gtb-f FroZ4n bllsal till
""8XU over otKIrOCk
Aholation t,ll
~over Ut!-
w ..dlt'lIVt-d
bedrc(:k
:'.:.·Iuvium over
C +B Oed rock and ,"ElXU XU bedrOCk
rf:w+BXW
CollUVIum over
wt'31hercd or
poorly consoli·
dolled bedrcck
SUBTASK 5.02
L
PHOTO INTERPRETATION
TERRAIN UNIT MAPS
[i£P II---_A_L_A_S_KA__PO_W_E_R_A_U_TH_O_R_I_T_Y---l
HUnlO SUSITNA HYDROELECTRIC PROJECT
2000 4000 FEET---~iiiJ
o
SCALE
RVS
T '.">-Ir ".,t ..r••l",
.,.d lOt"••'
fl.,•~.."
"U"...fl ,..,';1'
Kaq
":'fII)~,.";'II
V".Y ....Lloilo.(If II
{ •.,...,~~e.:J:
'0,1 ...e·II'Il....'-'.
......."'t;llll'Ol""tJ,n ....
Bedrock
Mappinq
Units
Tv Tsu -Tbgd
FOR CONTINUATION,SEE SHEET 15
Tsmq TKqr Jam (Jtr)(Jqd)RV Pzv (PIs)Kaq
Abbreviated
Descriptions
-enl.ry Vol(llnic
roc...~;,h.HOw
+flfrus,,,..s ..tI~ws ..•..,.tJ ~..rccl.'tlts;
I"flyglltll;Ie 1)...~tl<.
T.·".·V j.DI"'-'."111"
~.d'ml''''':'''f :)(10(-;;
tlin9f""le~:",..d-
,IQnll,1f'''C C"'4Y$lor-.,.
,,tU....\·t et Ie 'I '."'y ,,~"l t,
1l,,.l1t..'11f'r~'IT_Ill".('ld 'W"ilr,lIe.
n;Jrntlll"nCIt W~"I\Od C'.'"•..;)1'11 0 tl-j.1"Q01
fT'"lJlj)of Q.'~I)("'.
16fti.'y.'14 0'-
\""",r~'U"A gr.,...lies
r:>rm""o :t""...C)I'll'",
JI.V'UI _,"It;.!'i~'~'"
"1..11..1 'Ira [If Q!'"W_'"
)t:n·t !.",~rf)!loe.1
tro"dltlln I.I Jll )1I,'d
JoI.-.AJ ..It:.e l JII>.!.I.
~~,:'~,~,,~:~-:·,I..:.~
l~...o '"""11 w
....nnlt itllvlrol.lI,.ht.
Lalit .',HdUO.c.Lloi)l"I\t.
iIIrld "'N1~'\o ,.e:mel.'
volc6tnDQ_fuC'''OeM,
~t);:~met",·h,.,..~IOI'I"
'""\
...reI1lo..IIIJu!;,)"'Villite:
11'1(1'Or1ly....ka,of •
1I.1<f:1t.delo.r",.d
lur-b.lltilt.~QUt:·lCt;'.
Q ....or.d,r.'''HLlitmDrph'I!Jn
1rl.io~IC
~"l4 ,Jatl
,nteP"beJ:!1
Miscellaneous Map Symbols
Scarp ~Slide Scar ,<\f'Buried Channel
~/-~Troilr-'/
/j
Rock Contact r~/
Terrain Terrain
Unit Unit
Symbol Name
Unweathered,
Bxu consolid"ted
bedrock
C Colluvial deposits
CI landslide
Cs-f So/if'velien
deposits (frozen)
Ffg Granulilr i1l1uvial
f,n
Fp Floodpl"in
deposiU
Fpt Terracll
GFo Oulw<tsh deposits
GFe Esker deposils
GFk Kame deposit)
Gta Ablation till
Gtb-f Ras,,'till (frOlen)
°Organic deposiU
L-f lOlcustrll ,.,
(lrO/"n)
L l.cvstrine
GiCl sediments ove,.
ablation till
L Ldcustrine
deposits over
Gtb-f basal till (froan)
£tl
Solifluction
deposits (f~oun)
Gtb-f over bl.ul tIll
(frozen)
Cs-f Solifluction
deposits (froun)
G:tO over "br.\flln
titl
Cs-f
So!;Huction
Oepos,tlS (fronn)
Fill over terro1lca
sediments
C s-[~',fl4Jl..tll<m
Bxu del)(ltits (rrcw.zen)
over :le-tf~k
Gtb-f Frozen u,n.'till
tlXU over bedro.::.k
,;:.:$
Abl.Uon lill
~eve.,.1.1"-
weathllrc.d
OaOl'OCk
tfxu+BxU
Cl!iiuvlum fh'er
bedr«k and
tJe.:lrOck
Il(JJD.ure~
rE:w+BXW
Colluvrum over
wpathered or
poo..ly co"."oll·
dal.a b.(lroCk
BUBTABK 15.02
PHOTO INTERPRETATION
TERRAIN UNIT MAPS
IAPo[~II----::A--::L:c::A Scc-K:-A~P:-::-OW::-::E--::R=A~UT--::H:-::-O::-:R:;-:IT:-::-Y---jHUn[O SUSlfNA HYDROELECTRIC PROJECT
RE ....SIOHS.
2000 4000 FEETo
SCALE
DATE
livs
fl"l.5';':'etah-.,,,lt
"vIa il.,*,.)n
!1\1",.D4<{lo~d ~ihlllllow
JI\Ilr tile Se.:::j ~"e".
Kaq
.AOoO".rQIIIH,.
r.y......"It.f ..
oerO~,"fI(J
111elolllC:\'I"r'Cr;.
"01.."'1I:lAl'''''qU,'111.
-.
Bedrock
Moppinq
Units
Abbreviated
Descriptions
Tv
lcr-:"rv \'.o'C4-:1C:
roc.as:~,...t1l)w
Il'lt',.~......to r 1.0 .....
lil'lo~p...,'Vr 6S1.C-$,
r"ytll tiC.to o,!t1I1i\i.c
Ts'u -
Te-t,..""'o""-rnolll "fO.
.\l~lJN'I.r·:.r,.-c,.(1U,
lO'~lor"'~"4:'e ).4lf"CJ-
•!.ltr"l:,""'1':1 i..V.lo1P"H'
Tbqd
i er tI~ry c,olll ..
O'."'ot11cr-'te:loc:,1
"Ol"Tlbl""d...~r""~dl!:!nl
I;t1gd}.
Tsmq
l'HII"'-Y Idllst,
'''gft .111 ...."d .;r.nlre.
I ..nr">-e'll.ng 111'1'roof
gl ..I.,'U'.ICCI.,.
TKqr
Toerflol.ry .,no 'Qr
e rrl ....eou..Ur.It••,to s
r",""",If"~!,,",.I'~j C.!".
Jam (Jtr)(Jqd)
.,lurli'\.;;<II;.m>p'''''OCJ.l•.
II:tl~••.or"l"lo"'~;~j-
st:!:-.\",~...-cj.ltk..'Il
l r cndlllL..,,11l \Jtrl ,,11,1
ioI ......nod!Qr'lc (~ijd).
RV
Tn...."l(;lU'\....IlIL
rr..I.\I(lI~",nlC::'oc'"
•--m~l I"~tl ..II"..
mOli ...."'VlriP-,,,,,..nl.
Pzv (Pis)
tAle P".liDztllC o.&n.r;:
jj,,.,d lIl"'aIRltlle I'll.\.
V'tlt.:.''\CO*'mt:"oc'.
:.-c....J ~.lil·'flI~U~..,..
Kaq
C"ttUC.O~.~_"OIIl,Ii-
'""q.ayw.ao.ka,of ,)
\.,Ic ..",,1Qf<_n
lurr ojll«\cQUtlfICtL
1I)....Cjnde 1...r.-rnorpnl'Jln
I ,.'\.~,j;
.,.n...:tat!
,!v,·rue.1,
!T'A;"''''"
Miscellaneous Map Symbols
Scarp ~Slide Scar ;(\f'.-4 .~//Buried Channel ~Trail,
/j
Rock Contact r~/
1\
Unweathered,
con~olid.led
bedrock
Terrain
Unit
Name
,Solifluction
deposits (frozen)
Gr.nul.a,..Il1uvi,oI
r.n
Fluodpliiln
deposits
Outwash deposits
Kame deposits
Ablilt;on till
nils,.1 t,1l (froun)
SOliflu(tion
deposits (frozen)
over terrace
sediments
lacustnnes
(Irozen)
Laetatrine
1ediments over
ablation till
L
Collvvium over'
we<lthert'd or
poorly consoti-
d<lte<1 bedrock
L/lcustrine
deposits over
basill till (fro.zen)
Solirluction
deposits (frOlen)
over b'u.lIl till
(trozen)
Org.Jnic deposits
s.a!ifluct1vn
drpOS'U (frcnen)
over Oed~ock
At,llilion lill
over \/.....
weaU)t!roH:!
l:ledrocloo
Frozen oaul till
over bedrock.
Sclltluction
df'posits (frozen)
over ablation
tIll
Colluvium over
I!ftItIroCk and
b"drock
exposures
Cs-f
Bxu
L
Gtb-f
Cs-f
GIO
C
Gta
~
Gtb-f
Cs-f
CI
Ffg
L
GiO
L-f
GFk
Bxu
°
Fpt
GFo
GFe
Fp
G tb-f
~
C s-f
FPT
Gtb-f
Terrain
Unit
Symbol
SUBTABK 5.D2
""Efxu+Bxu
iw+BXW
PHOTO INTERPRETATION
TERRAIN UNIT MAPS
rAPD[~]I---_A_L_A_SK_A_P_O_W_ER_A_U_T_H_O_R_IT_Y~
HUn[O SUStTNA HYDROELECTRIC PROJECT
REVISIONS
O~~~2~O~O~Oiiiiii~4~O!.OO FEET1-ISCALE
OA.TE
RVS
~rUl:"'("'81 ..0"'0111
"Ill:.llite ...of'
,'·Ier i,ool,(lp!.l'1l~,I:;....·
.......'1 ...~Iln'.""r ..·
Kog
.a;:1l0US a1"Jiltl!+t~
O(.ywJl~k~,6f a
~Uc'ero-m",d
,,((It....IKlUI!'1~It.
r~[]1i!~t.anxlrpjl,.m
Bedrock
Mopping
Units
Tv Tsu -Tbgd Tsmg TKgr Jam (Jtr)(Jgd)liv Pzv (Pis)Kag
Abbreviated
Descriptions
't'rll~ry VCICilnl(
reeks.:,n..llow
'....\ru'tlve\.HowL
Mid Py ...::>t.l ..'h(~:
rl1yolillc :00 DoU,.'IIC
I.nO;)r"t'~"-'I <\l"lrle
:.IlI<l'nl ~ry ,:.<.i<s.:
conlJkIPt>~r31",",,-d-
s\on,.Jno CIGY~lo'1•.
r~tl...ry biotite -."IIBry SUllt[,
Q'-IU1!:K1 ,or,lot";Wof.ltl ""WIi"HILe ~1'Ul gr""II.,
hu~,.,.~llInC1'"gn'f'lpd,orite 'titl"-"IU'lII.'g Hut l"C'Ot
t TI''iJ,j).cr =J l"r'"CIlII Sl~~k
T,·rll.()rv .<In(l,~r
~cr,,:~::J~';..Yir~~I,,~~~.
.our.ss,!;lImorlO:JIHllt,
.tl'i;I••:>oi·H·"~01 Q....-.,•.-
stf'l'·lI.c.mlll1"01,,:lQoC;:)1
tr(lrtl:!I'l'l'In1~'Jlr i W·,(l
rJrlllI'Od O"'l~,,'9::1).
'-.,hStl.~dUoillJ;
f11illl .....IlII".'nIC ,QoC"lo
rg~j Ir'I 1h411ow
m.rll"l~.-nvlrQln.mlllnl.
_:"iIII ~'JH"C blOll ..lll,;
,...,..,~I "-'Ce;,'\,-"",I ..·
vC).C....~""'C;rl;K"~
0:.1",.,:,.II 1'nr'"11
,:J ~j
C.".I,,~eav~IIT~.I 'Ie
PIa 7"....'~...c:"..,"r ...
l"'oc;~",,1"""'1110
lurl1,Glli11 )ltQlf9l'tl;lII,
,nw!::lru1..Irlltlitr'ltJr'PI'I"'l'l.
lr"ul.C.,
"ttd ~''''\''
In/erDouet
Miscellaneous Map Symbols
Scarp ~Slide Scar J01'~/
Buried Channel ~Trail ,/J
I
/
/
Rack Contact ~~
Terrain Terrain
Unit Unit
Symbol Name
Unwe.thered.Bxu consolidlted
bedrock
C ColluvIal aePD~ltJ
CI Landslide
Cs-f Solifluction
deposiu (frozen)
Ffg Grlnull:lr OIliuvill
r.n
Fp Floodpl",in
deposits
Fpt Terrac.
GFo Outwash dtposiU
GFe Esker deposit"
GFk Kame deposits
Gta Ablation till
Gtb-f RCilal till (frozen)
°Organic aeposiu
L-f lacuslrone!>
('rozen)
L Lacustrine
Gte sediments over
olIbl.tl,on till
L Lacustrine
deposits over
Gtb-f ba:;;al till (frozen)
..c.ll
Solifluction
deposits (frozen)
Glb-f over basal till
(frozen)
Cs·f Solifluction
deposits (frozen)
Gte over ablation
till
Cs·f Sollfll.lction
deposits (froan)
FPT over terrace
sediments
Cs·f Solifluction
BXU Clepo!>'ls (fr'olen)
over l)ed~oc'"
Glb·f Frozen b~ul till--sxu over bedrOCk
Ablation till
~over un-
weathered
bedrock
Cc3?ruvium over
-ePxu+Bxu bedrOCk and
be-arock
exposures
~+BXIY
Colluvium oVllr
weathered or
poorly consoli-
d ..led bear-oel<
PHOTO INTERPRETATION
SUBTABK 8.02
TERRAIN UNIT MAPS
lj.[QJ f---_A_L_A S_K_A----:PO_W:-::E-,R,...,--A-,UT_H_O-,R-,IT_Y----j
RUn 0 $USITNA HYOROELECTRIC PROJECT
2000 4000 FEET
!
REVISIONS,.
o
ISCALE
D....TE
RVS
T....,U,.(..,eu:.o..osalt
..r"t2 'i.•n ....,.,
I le~::ead..l'~s··..lIa.....
,."~~e;:,\4.,.,c•.
Koq
"o(lOU""'";;JllIlle
r ..y ..~(""..f d
d.IQrrn I;l
ott'"~Q\J""::".
lC1fo -·!'I.>t",:,"-pl1 'rn
L
Gtb-f
-
Gtb-f
8Ql
Bedrock
Mopping
Units
Abbrevioted
Descriplions
Tv
I ••:"'~'r'VOIC0I1'J ~
r1)r;;h'~·I.IIU'"
t"",l>'V1!l~..l-pw""
ana OV·~(.i.Il:.
"n)'oI1.1:.:0 b4J.1j11t~(
Tsu
1.,flJ.ry oon '1'1111"1"'"
~IN otn\lll1f ",....:i .
'f't[1QIOIl'llrl,H:,,.lInl:Z-
$-!.a"f .•M r.1.IHIlII"•.
Tbqd
1 en,.,y "'lO~,.
~r.nel'!lorltc;,""'-"
"arTInl",nQI'l 1i11".~IO"-'
(T''II;l'1I.
Tsmg
"lin.ary ~(:"'llJl.
1'1,~":t.dina ;;;.,-""",.le
"clI'rl!lllocll1"'O 111ft -=(
of oil a'OIl!11ol:k.
TKqr
T .,:;~~,y .,nil ~r
...rJ'l..-(..D.....g:"""IlLt
ftl""'''''i3 :""',11111 (Io1I1l'lI.
Jom (Jtr)(Jgd)
,ILJr_u l..'JI':)~.CJlJdl".
1"Tt''''.7rl><";n.,..n·
•.:....,·~l ':l'I'l",rtll,,;~I
I~O"lJllII!"".(e I H')&00
'"8.'00IC r"11 t r .rllJd ~
RV
r :.~l:t ..d't'
,.",r I1'I:."x:.rr..c"~
'conn.C:1 t ..411 :W...-.nc t'''''II'(]'''~111
Pzv (PIs)
lJl~"~.h·;::w :...,''r
\nf1 ~...,:••,r """1 ..-
,:;'I:.I'l~!10".,
I'::JI:~rntl'\011 IOUUll;»...•
~l,;
Koq
C OJ'"a..Il ;J"Iii'"II
'Or':'~r"y-6<"•.""J
tn ....o...IQrwl.)O
u..."I,i·al'.:h:,J.nlll<:.e.
ItJ"'<Jfa.JIiIII~L.tlloGrO"'ttll
f"'••"ll:
oJ,1.111'
1111 ..rt:I.o::
Miscellaneous Mop Symbols
Scarp ~Slide scar;(\Tf
~/
Buried Channei 9 Trail //
/
/-
Rack Contact r~/
..
,
/\
L.lIcustrine
deposits over
bonal till (frozen)
Terrain
Unit
Name
Unwe~thered,
consolrdated
bedrock
Colluvial deposits
landslide
Solifluction
deposits (frozen)
Granulilr alluvial
Ion
Floodpldin
deposits
Terrae"
Outwash depOSits
Kame deposits
Ablation till
L
Sol,!I"ction
de»o!>I!!>(frol:en)
over terrace
sediments
Colluvium ov~r
wedthert'd or
poorly (c~',>olt·
dated l\.,<zrOCk
Organic oeposits
Lacustrine!>
(frozen)
Bdsal till (frozen)
~-QJlrIOctltln
d"P'O,tts I'rozen)
o ....r b~':r"Pck
Lacustrine
sediment s over
C1bl.;ltion till
Abl ..tion till
over un-
weathered
bedrock
Sol,fluction
deposits (frozen)
over ba.s.1 till
((rozen)
Froan b.a,,1 till
over bedr:>''''
Solifluction
deposits (rroan)
over ablCltion
till
Ci,g!luvlum over
1J'8<;rQ<;;k <lnd
Dl!'drock
exp~~Jres
Cs-f
F""ii"t
L
GtO
Cs-f
GiCl
GFk
Gte
~
Gtb-f
Bxu
Cs-f
Fp
L-f
Fpt
GFo
°
CI
C
Ffg
GFe
Cs-f
1l""Xcr
Gtb-f
tfXU
Gtb-f
Terrain
Unit
Symbol
BUBTASK 5.02
tfxu-+Bxu
~+Bxw
PHOTO INTERPRETATION
TERRAIN UNIT MAPS
1_,nofP If------,-AL:c:-A.,....S.,...,K_A...,..,.."P:-:OW..,..,E::-:-R-=-:-::A:c:-U:c:-T.,...,H:c:-0.,....R",..1T""Y,------jRUn0SUSITNAHYDROELECTRICPROJECT
CBxu I B~u
Jam
CM.A/".AP1'IiEVISIQNS
O~~~2~O~O~O_iiIIii4~OOO FEETSCALE
L
RVS
",I~SJ.'....·,,:jt.CI.aa...ll
""10 11":R"..-,1
Irlf"r-brdltttD "fo1l"'P""
~T-cl(o,(U-ltl"'ri:!.
-v-.
Kaq
LGfb
:...:4.:tl.a .."VI.to
~r ..v,,-~~,...Jt .lI
k O'l·or,.-.·...,
>I:tll"Ilq"."f:,..
iltalllllrJil(Ii./f'CIl"ttlll.m
-
-
L
Gtb-f
~--£.+B)tUBxu
''1m
FOR CONTINUATION.SEE SHEET 12
Bedrock
Mappinq
Units
Tv Tsu -Tbqd Tsmq TKqr Jam (Jtr )(Jqd)RV Pzv (Pis)Kaq
Miscellaneous Mop Symbols
Scarp ~Slide Scar ;(0'Buried Channel
)
/'
/
Rock Contact ,--..J
Abbreviated
Descriptions
1""'-\''1'',.(111;111''';;
r;;.c",.:'''.''r;lW
""~fiU"..es.(I"...·!>,
IIlld r,:,rg~I.,tl~';
rhyOJII C LO IIJJU.jIlIC
r.,1,{I"V ncJ'o"nl;;u"lIte,
"lo.:-d'l'l',.t tll'Y .."-::k,,
;:..-'1 CJt-I"'Il....:ot ~.;"l,d
Slon..(l -c:UlIYlolont
lltr I .,rv tll()tl:\I r,,"'\1.''1-'~~"I.l
G'"n.:J.!f·~rl'.~:::'II;"J "'IT"~~.."II~Iilr';,nlll'
Mg,rl)l:Ilt'1"!u.gr"nodl;;;nle ~'lr""~I'ltll'Q Int·rQa'
\1 t.'O(1),::or ..lfIG\!';1)(",
--::;:?Trail ///
""".rt'llI r y"rrc!,qr
.re"iJ:.-ea..,OlrOl'\lti-;
fCl"""'1"\'iiI ,m~1 nllllttn'
J.J".U ••mpr1 tID I...,
,nrll.'I·......."I If'"""~
~~hISI f.1'I1.r::.0'.Q..I;;.III
lrr:r1(111f'T1'l'lr:o Jl'l .no
qr,Lr,;JJj'a"':U:9:;l1
'r I "~~Ir :...:.-'"
"'.'I.,·nlt".r~,,;~',1
!orlll"[1 I'"."..mw
I"'1J·II·"IIInVI~~ll'l\
:r ,-~".:...l '~.........I tit.
.";1 -"10",.,1,'tpv11fl-
ol~lIrKll,;""'"r...,......
':Joe.1 1I1I:.'III'''I1I'1:IQ,'"
I'::'h.'
r~~t...~...lOra II I.
,'f'''!P~~V'""roo".'II "\p.,.,"r',rml,,"l
1o.1I14"\.t-M::lJo;'ll;'.
I)"Iil -"C:~fI'Ir'Hl"lDI 10't..!1"
T,"'.J~;
....d'.~..Tf
'Ai ....04!!.l'
mart II '"
Ablation till
Over un-
we.lll..~"j
CIOroc ...
l.Cvslrine
deposits over
b"ul till (frozen)
Solifluctior'l
deposits (frozen)
Over basal t,lI
((rozen)
s.ohhuc~oft
,jl'po:l.l~1I''Ozln)
ever :',e\7fT'c"
FrOll!!'''baul till
over bedrock.
Colluvi-um over
....'e..lh.....e(J 0"
poorly ~fOlI
dated b~rtt"'C("..
Solifluction
deposits (frozen)
Over terrace
5ediments
Lacustrine
5"d,m"nls over
.blation till
SOliflv:tion
deposits (froz.en)
ever "blat,on
\ill
L.KUslr",e5
(I ~Olt!'1)
~l'Ijl.uv .In-over
O..drOCI("nd
....-::~~~es
.-L-
Gtb·f
L-f
Cs-f
Bxu,
Cs·f
GiCi"
C s-f
FPt
~
Gtb·f
Gtb-f--exu
BUBTABK 5.D2
tfxu+BXU
E&w+Bxw
Terrain Terrain
Unit Unit
Symbal Name
U"w~.ltlered,
Bxu co"~OlidaleCl
bedrock
C Con...",ial depot,,;ts
CI l.ndsf'de
Cs-f Solifluction
deposits (f.-oun)
Ffg C,.."vl,Jr alluviilll
r.n
Fp Floodplilin
deposits
Fpl Terracf!
GFo Outw,nh depOSits
GFe ESk,lr l.Ieposill>
GFk I(~me depos,ls
Gta Ablation till
Gtb-f Io'\a:..'lill (rro.lcnl
°O,.","n,""lIilIPOS'U
PHOTO INTERPRETATION
TERRAIN UNIT MAPS
IAPDI~Ij--_A_L_A_SK_A_P_O_W.,,--ER-,---A_U..,....T_H--:O--:R:-:-1T_y------lnunaJSUSITNAHYDROELECTRICPROJECT
REVISIONS
o 2000 4000 FEETc::=.---JSCALE
DAl£
RVS
,,.,:t,l;~",III~"D"&F''l
......c:la·1lI1c."11
11e""E:l(j~d 1~,jlII4I1W
rr..u-..nr lIf.J..."nt.,.
Kaq
.c:ttOtll!'l"~ill:11R
l'.ly"'tK"~Ir I
..:14)""1"(:
,f ,.,......,.I"f"'Il,
~~."".f9lClTpl 1m
"".:-.
Bedrock
Moppinq
Units
Abbreviated
Descriptions
-
Tv Tsu -Tbqd Tsmq TKqr Jam (Jtr)(Jqd)RV Pzv (Pis)Koq
lllrU..,.y VDlunic 1er'tl.ry non-mOil If't~"7 t'~t lOry tI,utl..,""I"t,u,·v ~(..III'I.-,:""tl..,.,,.il~ltj/O'"JU11lU:""pfillol>-,",r"'1,,",CJ..I+II'::t·o1l'\.>,\'~C;"'Jtl baSlt,1 C t.:''''a!~,..:"'II',.lite T r,.'\~."
roi,;,,~;.olIlIow 31edl",,,ntary ro;x<"\s;grhHod tlrqe;IUl ul r-7tlilmcllli'.~ICI 'l)r...,ilt,_rl!~Il:~I~gr.nill.n ~lrll"c)IU 0',;t'Cf'lIl-"'1"v()lr.).".c ~;.:~.""Il"U.I\lQ 1'101"-,no :;l'''.''w~l:''.,",.""."tr·u~,v.!o,"")ws.~M.gIOme.rat.",~nd-t1"r.Jr'"\ble"oe .;r"Il"dlj)'·l,..""Q~"l1""'l I\g 11'"'00'rr;:rmlni]_II plUI~ll.fll'l ,'1"1 ...1:11_;(01;.""10"1"'"'..:1 ·t.)....a·'t'...'"~Il;..r-oi1 ...nIC t'oc:~~,~~'-':$1.'1"'I'f'0.no pyrOCI<l!ilIICS;Slone,'Od Cl..ystone ('Jgd'."'-lJ r :g4-$:~k.1rt)l1fll..,·ll.(J11'.no rlne ",'\VIl"O'IL"••,\L 1=0 mll'll.-I.m"SLa"..,flll~'n\JL.oI......e.
rr'lyol'llC '0 ba'aJtic.~ra".u(ll""lc:,Jv<.l ~.\",t-p.lct ....'I"'.Iln 'ft"!a1I:KI~f1tl'l'"
Miscellaneous Mop Symbols
Scarp ~Slide Seor ;(\l'~.~j/Buried Chonnel ~Trail r
,---/
Rock Contact r~/
-
L
'GtD-"f Terrain Terrain
Unit Unit
Sy-mbal Nome
Unweathered ,
Bx~consolidated
r>edrOCk
C \.olluvia'depo,its
CI Land:l.lide
Cs-f Solifluction
depo)it,(froun)
Ffg Grolllnular ,Illu....i.1
I,n
Fp Floodplain
deposits
Fpt Terril'.
GFa Outw,uh deposiu
GFe E)ker unlJosits
GFk KClme de~:l(uit5
15 Gta Ablaloon t,"
"-
Gtb-f BitUl till (lrcan)
0 Organic deposils
L-f Lacu51rlnes
(frozen)
L LacU!lrinlP
sedimenu overGtailblationtill
L L<.icustnne
d~posjts over
Gtb-f b"sal till (frOzen)
SOlirluctionCs-f depo~.ts (frozen)
Gtb-f over b,uall toll
(frozen)
SolifluctionCs-f deposih (fro,an)
GiCl ov~r ablation
till
SOlifluction
Cs-f depos,t)(frozen)
FPI over lerrilce
sediments
~:!iovliflu~liOf'l
dopo~'U (f"'Olen)Bxu 0";8"be!lrlKk
Gtb-f Frozerl !l~1i11 lill
1rxU over be~"'Ot:k
Ab·lI\ion \.11~Dver un-
welllt""~d
be.(Jr~k
~nuvium over
tfxu+Bxu ~r.oc:k"'r')d
tledn:lc:k
o:"wsures
COltuvium ov.r
Ff-+BXW wr4llher.d or
POOrty cgnJol!-XW dOlled bedroek
O~2~02
L
TERRAIN UNIT MAPS
BuaTABK 5.02
PHOTO INTERPRETATION
&nom I ALASKA POWER AUTHOR ITY_II--~s:":u~s'':'T=-N--A-;-:H-::Y::D::R::D::E:-:L~E~C;T-;;R-;;'C::-~PR~O~JE~CCTT-I
RE ....ISIONS
O~~~2~O~O~Oiiiiiiiiiiiii4~O!OO FEETtSCALE
DATE
RVS
rr.4I'·."'1'M/IIl:l.4I~4:
•.,..,"fl~./11'-
""'''r'1llllld::llq 1"'''110''-
"..,r.ne ,...q"'lI1lt"e
Kaq
..".;:0.,.010 frg.t~
r;...·Y\'..c~.,,..'.•
<0"'0","l1li(1
~:;:~~==.t,~
L
Gtb-f
L-f
FOR
-
Bedrock
Mapping
Units
Abbreviafed
Descriptions
Tv Tsu Tbgd Tsmg TKgr Jam (Jtr)(Jgd)RV Pzv (PIs)Kog
Teniary V"lt .~lrc leni~"'Y """"'n111rlnll ;jr~tuvy tI'Cllte T(Olrtiary ~cllist ,Ter"ary dlor ,",ur.:;'uc .Il111flnlCDI.te,-r iJI'Ifi("o.u,llioc;L<)tl':iI',t4eo.l.oie~..,C"'-noll~.Ou~~lIllte T r'/I~.s-<
'-0r;;;10..:·,!'..lIow ,,,.~,,,","[.I,..y rc:;::".lijJI"al"\Miar:le;JI:'tfll l'"IiO'"'I.·uiu.a;',d gr.."r1co,Cr*tact<n.!'\Onlni'in .r'1(tl.lllCK'!..,grr~"-rnltl,...DlcOIn'l:"",,,~nd mdMH c=I.,.t~-.I(1(l'Jr•.,,"'.iII.('ke,of .M1d ~,a
.nlrU)oIVIIl),rio ...~,~1llIn.g1CIT.~r3{e.IlIT~L1'~DrrJQI d''-Jr"N;Id~Vrll ~pre~!wllng ,h,roof forrllln'O 111'1\.&11 lllt;!lms.~ctlill ,,";Hul.;I~~tl rOl"~d In ,-t'".llow '/Q 1::.•1'>09.....c c~k ..,trllck dt!l~rmed tritt-roe,
.nd oyrQCI."LJ~s;st(Jne,U7ld (11I\'~to::;ne.(''''Od).0'.Illr..,e .'Stock.lrQrdjeoro,le t ~t~,'nd n.lrfrl-""nV'M'!'·-tnr11 I~~'!PHIII"''l"'1dto..ne-lurbj~lll"Se'l.lUflf\CI'I,
rhyC'jti;:;"ba3.illt c Jrltnod"lur;le (..I,t~I"11'111;lo·...'t;Jf.de.I't1t!UI"r.on:lr'"'"'1
Miscellaneous Map Symbols
Scarp /Slide scar;(\TT .-4 .~//Buried Channel ~Trail /
/
/~
Rock Con locI /'~/
Terrain Terrain
Unit Unit
Symbal Name
Unweathered,
Bxu consolid<lted
bedrock
C Colluvial deposits
CI L,mdslide
Cs-f Solifluction
deposits (frozen)
Ffg Granul.:lr alluvial
I.n
Fp Floodpl"in
deposits
Fpt Terrace
GFa Outwtlsh deposits
GFe Esker <.Jeposil~
GFk Kame depos,ts
Gta At-I,)tion till
Gtb-f Hasil)till (frOlen)
°Organic depoSits
L-f L"custrines
(frOLoin)
L Lacustrine
GtO sediments over
ablation till
~Lacustrine
deposits over
Gtb-f b,nal till (frOlen)
£U.Solifluction
deposit.s Uroan)
Gtb-f over basal till
(frozen)
Cs-f SolifluctIon
deposits Uroan)
GtO over ablation
till
C s-f
SOlifluction
deposits (frozen)
FPt over lerrace
sediments-SolirluctionCsd
Bxu deposit!.(frozen)
over bedrock
G tb-f Frozen b",s,,1 till
"llXiJ over bedrc~k
-Abldl,:in till
~over ur>-
weatn~rf'd
bedro;:k
tfxu-+Bxu
~Iluviunn over
bedrock and
bedrock
exposures
~+BXW
Colluvium over
v.'e,)lhered or
poorly con~oli-
dated bedrock
SUBTABK 5.02
PHOTO INTERPRETATION
TERRAIN UI\IIT MAPS
~i f---_:A-:L-:AS-:K-:A~PO__=_W=_=E_:R:_::_=A_:UT-:H:-::-O,...,.R::-:IT-::-Y-----iHUn[O SUSITNA HYDROELECTRIC PROJECT
REVISIONS.
0'iooo........2~O~O~Oiiiiii~4~O!OO FEETSCALE
OATE
RVS
Trr;".~lr rt"1I(.,oIlUH
lind ....I .....In
t"1\~"b(:l;1o"d ~hdliQW
ni!or,ne :"CQuence.
IFfOUS.~rOlil ..(e
.;('.....w~'t:ke.of a
I<.d,.·o""~lI!Id
).0 II!'~eqlI,,("lCe,
in;,1e mf·(...m(J··ptll~~
Kaq
I
...c...
B t Bxu •.,xu _.,.'.~
FOR OONTINUATION,SEE
FOR CONTINUATION,SEE SHEET 9
Bedrock
Moppinq
Unils
Tv Tsu Tbqd Tsmq TKqr Jam (Jtr)(Jqd)liv Pzv (PIs)Koq
Abbreviated
Descriptions
,.,,-\Jil"'y \Cl'Ic.llnlC
rorln.I .110 ....
nl~"'~lvl!'S,(IOWL
<lnd Oyroc;lI,·,Il.(.S;
rh~(tIll Ie t(.L!.:lul\ic
T~',.W¥l"C!···"'I..-n..
:r,'·:1,ft.II'IU""'Y rO'l..'U;
Co""'CitI()llllIlT.,e,5ll1i"'1d-
Slognt,oilno:CI .....'lor'\O!
iert,"'ry 11lIl'te I ...·:,;rv sc UI.
g ..~IlOOIOI"II.;local m'Dm...\1...lf~1')OT"",',,!,'.,
hDrrl~I"rlde (;r"r<;Jdlonle "opres~:.nc ltl"r(Jor
(T.'gd).0:..'."qe Hrx;....
-.fliary ,lnd/or
,,.ctllC~U~.grln'tle,
fQrl"'lll1'<lJ~lIol.J:c•.,s.
lur.s!>,c n.:'lt'oJ,t_
kJ..I;;IuJlOrU of ~t''''''.
,;l'l;lst &m..rD',,:'Q(41
\~~I~If'lJlr)'"<:I
gr.H~l'llar 1"i JQd I
...~1'f'lt:b.••'Lu:
....ljj·~.:JI(;.nlt roc...,:-
lorm~.(l ,ll ,h"ow
....rHlP ..nv7TOT·'·.......I.
;'<J("1>~,~··7{".C ~iI-:li ...~'c:
.....:j n;,.,II'1;l'I'I.h,
,.;p'(.I~..n'(.rock,.,
III '"m........-.I'T\c.:dl1"lI!
Ilr1,1
\-!,"rt"<:lIEl1.a _nJdhl'"
~"d g.-a,......-:l\...,IH if"l.d.~.'OM":c.r;;I
t ...ra !),Ie ,eQUiline.-•
Im''Q'I"rtn""'1I1.",nNlnllm,
Tr ...,\:
.r'll ..I_1
·nc"r!)..d't,.,1!~1t }
Miscellaneous Map Symbols
Scarp ~Slide Scar A0'Buried Channel
~/~irail //
I
./
/
Rock Con tact ,-.J
-
Terrain Terrain
Unit Unit
Symbol Name
Un.....eathered,
Bxu consolidilted
bed.-oek
C Colluvial deposits
CI L"ndslide
Cs-f Solifluction
d"'poslts (fro.:en)
Ffg CI"..nulor .lIlluvi.1
r,n
Fp Flo.;>dpl,.,n
deposIt!.
Fpt Terracfl
GFo Outwun deposils
GFe Esker lJ.po>il~
GFk Kame <;lfposits
Gta Ablation till
Gtb-f Bonal till (frozen)
°g.-nk deposits
L-f Lacust,.;,,1U
(frou"')
L LClCLoslrine
GtO sediments ove"
OIol ..llon till
L L"Custrine
d4lPClSiU ov.,.Gt"b-7 tlilUI ill (f~Ol41n)
CS-f SolIfluction
deposits (froun)
Gtb-f over b.tul till
(frOler,)
Cs-f Solifluction
depOlllts (froun)
GTO ov~..ablation
till
Cs-f !lat.huction
dep(ldl$(frozen)
FPt ave"terrace
sediments.
Cs,f Sollfluctlon
aeooi.ts (f,';::u'n)BXiJ e ..UlIc:,.<X;k
Gtb-f Fr()l bUill till
""BX"U O....er tle.dI""QC1<,-At)l.thm till
~Ol,/tr un-
XU wulth.....d
bflO"oc;k
C +B
IliiiAItuvlll.~LlVQr
t11Kl"rocl<.""d"ElXU XU u-.er'6ek
~,,~:Sures
~+Bxw COlluvium over-
we"tn-Ifr-ll'r:l or-
p<Xlr-ly ,:;onsQII-
dAted btl(lr-Oc.:k
SUBTASK !S.Oii!
PHOTO INTERPRETATION
TERRAIN UNIT MAPS
i APOW II-----:A:cc-L::c:A:cc-SK.,-A~P:-::-OW=E--:R:-::-::-:A:-:UT--:H=O_R...,..,IT"""Y---lHUn[O SUSITNA HYDROELECTRIC PROJECT
2000 4000 FEET
:
REVISIONS
o
iSCALE
DATE
f'n.q,,:"....I/lnA"lll
.I"I~~I.l•.'In
1'\1 ..t'"~"l}.QrrO s"'~llow
~Oll .::~~'t'Qu"nl;e.
livsKaq
'c ....'I,;Ililft
1,l'·lIIv\~.a,"kft,Dr ...
.JlrCl'ft'lIld
elite HQuel"lti
-~af!'ll't1*llIOrOfIU1II.
/
FOR CONTINUATION,SEE SHEET 18
FOR CONTINUATION,SEE SHEET 16
I,,
Bedrock
Mopping
Units
Tv Tsu Tbqd Tsmg TKqr Jam (JtrJ(Jqd)RV pzv (PIs)Kag
Abbreviated
Descriptions
1 f"rI'd~)VI,I,I;;:':\1'_
roc;..~:'1r .\llol)'W
In:....III'VIi'.~.lit)ws.
~nc \·~t"l'l;""
rrlycll\'c 10 'u..,4Itic.
;"t~l'ilr\,n'l-·-wn"nnll:
!I ""'iII'"\'roc"":
(;C1roo.OF'l~·.t","-.'no·
'IClne.a;,b t.I",,,SIC:'U.
Tt.rl,.Hy I1ro\",_-.:~(\..~...iC"I\I,
Or.Nott ::IC".I ..;local ""O~iftllc Ina gr.'l.Illlt..
norTibl"-IlClI g .....nov,ol".a I t!~'.!"t:-lll"tJ 111e-.::;o(
CTtIQfl).'of It fAr-Cltt 'j(OC:".
T~I;.""y 1111 ,Cit
C,IHK,r.:J.l1"1I"'iIIot\'l .s
!~I'""I"r\1.l :>"'''11 t..l'~~.
,~"'..s.'I'1:A"f\OOn';OQllllfJ
'1'1(;"~·Ol"l'.or lJl'"c~l
:."lil ~I'I~",)I.'I ....,,'
\r']I'\",.....,,,,(.fr,-.0
,;,,,<"IOQO"II.fig;])'
Tt!iUSj':to",...'",",
..l~vdoll ~':31;'"
"11 ",'UIlUw
,".'lI'...."'v ~1:l'1fl'1tl"1
ioU-1',,'r-~I"'C"p",j;.~c;
6:J '.t1~:llt'1'1101 .....
,,~.I-,:u,.""l 0;;10...,
"'lo;:..j .,..,.l ..."".,,,,r....
:r ..tK'lOloo1o ""Olllli'
All!:!"".,.".,,';"••or ~
1f1'(.'-a ..u:no ..d
lut roll tOf ........,,,,,".
1C1"rr.afl "'..I,rNlrl'lt'1m.
-~.,,;.-
.".,"I'"·.,.,rt:lorc.:
Miscellaneous Mop Symbols
Scarp ~Slide Scar A0'~.~//Buried Channel ~Trail /
/
/
/
Rock Contact r---J
o....n APRIL 1981
,"'O...cT 052502
L
SUB TASK 5.02
PHOTO INTERPRETATION
TERRAIN UNIT MAPS
I APII W\I---,A_l:-:-A:-:-SK:-:-A-----,Pc::-0W::-:::E-,R::-::-=A-,UT-,Hc::-0,,-Rc:-:I T-,,-Y-----jnu[0 SUSITNA HYDROELECTRIC PROJECT
Terrain Terrain
Unit Unit
Symbal Name
Unwe.lhcr'lld,
Bxu consotid.tlld
bedrOCk
C (:olluvi~t depo"lu
CI Landslidll
Cs-f SolifluctIon
dlpos.ts (frozen)
Ffg Gr<lnvliu"alluvi,l
r.n
Fp Floodpl.in
deposits
Fpt Terrie'll
GFo Outwash depos;ts
GFe Esker ui'!~osiu
GFk Kame deposits
Gta Ablation till
Gtb-f Baul till ('roun)
0 Organic depos'ts
l-f Lacustrines
(frozen)
l Lacustrin.
GIcl sediments over
..blat,on 1111
L L~lCustrine
Gtb-f
deposits over
bits.1 till (frozen)
~Solifluction
deposits (frozen)
Gtb-f over bdsal till
(frozen)
Cs·f Solifluct;on
deposits (froun)
GTcl over .blalian
till
Cs-f
Solifluction
deposits (frozen)
Fiil over terr.ce
sediments
Cs'f Solifluction
Bxu deposiU :fro.ten)
over b ,,,,,"
Gtb-f FrQZert b ••al Ii'
"""BXU ov.r b.~dt'oc.k
"...Abt.,;.g,'t ~'i
~ov.~.1"'-
",,,.I"'pr ..~
bedroc.k
~lIu"11\over
tfxu-+BXU be(i'-OCk "nd
t:J~Ol"OCk
e:<poOosures
EEw+BxW
Colluv,um over
weillf"1ered or
poorly consOli-
dill&Cl b&drack
O..._~2~O~O;O_~4;;:j0'OO FEETE
REVISIO~'
SCALE
livs
r,.fC1ir l1".ttlo!:Uu'l
.It I II "1",t~
"l....b.odollh:slU ~o.....
Kog
EET 16
..:cau~.....'"'II"."........."c"•.01 ..
.:Illlul"""'ItId
"II'fl "1'lut'nl'C'
".lld".....~.I'O(l,.Dl"I .,.,.
-
Bedrock
Mappinq
Units
Tv Tsu I Tbqd Tsmq TKqr Jam (Jtr)(Jqd)RV Pzv (Pis)Kaq
Abbreviated
Descriptions
-.pt'lillry \,!'OLC-.".t
11"«,"-,:I-I"u,.lIow
'''t'J'tJVC'i.(lows,
twd P\"I;l(U'~l .:s;
r"y o~11'1:10 tle s.a1l ic .
Terry '''C:Il'l'I''''IJlrl'Ht
H'Id,~,t'·ll ..·y rCCl<.Io~''''.-'Lft'''l ..·"le>"'10"""",0
'\11111"'_lIl.d il'.V'!.to".
T."t ,.rv bttlllll,·ll.n",-·y ~("'1'lI'l,
Or.orJOdIOl".'...tI~ol "I,IF...I Ie J d ;J"Jn.\e
t'\.O,···t:j~'.,,*lC ,,~~'1.><1111'';00 rel'"~""IiI')i'''''ijI 1~1"....cor
(i!')GcJ'(It.J .roe ~W~lo.,.
~~rl lit."illld/lJor
C ....t.~<...'!Ju!l !,I'",lll!lLS
frir""'l1"1/11'11",11 DJu:-:;r'~
IIoJr-Dtsi,"mpt 1;.;1 t",I:.
'n...I.I:l''l:'1'\.''""f '....,
•"Ill!.l.''''''Ilr '111 .1
t°'1')f1I1Itr1"1 1...(.Ll.)til l\'~
gr..rN::r.'''~''''.,190;1)
I r·~..t11o b,hilll,(:
W""h't'.JoI'",'k",
1~,..-.nI'l:1 n "'1(1"",
'."11'''''''''-(11'\''"111
l ;H."01 .Q~QoC tJU.fltlc
al'd "'ndI~~t II:m.IItil-
vblc..r.Og..,,11;rw":,.
I~"I I"lllt..ll·I"'""lon"
(~t,.)
Cr-o:u.e.Ou~arglll \1
""nt!Qr...."wa..:~tt,(,;1'<l
1'\,'1:_OlllT;1"""".~d
~ur nIl!!'llu:~~Jon~o:.,
lC',,~.,lhlllll.lIll:Il"'(1ltllm
11'",.1..2'1;
~~..L.
,m"rt:l~'
rTI~r'rr;c :
Miscellaneous Map Symbols
Scarp ~Slide Scar ,<\T'
//~y ~/Buried Channel ~Trail'
//
Rack Contact r~/
Terrain
Unit
Symbol
Terrain
Unit
Name
Bxu Unweathered,
consolidated
bedrock
C Colluvial deposIts
CI l4ndsljde
Cs-f Solifluction
deposits (troun)
,
1\
Solifluction
deposits (frolln)
over lerrdee
sedi/1li!nts
FloodpLoIin
deposits
Esker cJeposib
P>bl.ttion ti'l
Lacustrine
sediments over
ablation till
lacustrine
deposit..Ovt'r
b<lUI till (irozen)
Coll...vium over
WHI .n~d or
poorly coft'lOlli-
ddtfil o~rock
Granuli:1r lllluvi.,1
ron
SCI1l"Ul;tron
amQ\to.It,-ol.en)
o"..r ~e~~k
Fro.ze-(l lUIul till
over bedrc<:k
I,tll.'IQoO till
et",ltr un"
""'It;l.tf to'-o;,d
bMlll"OC"
~hlVil.m over
hedr.x:k ll"'d
bt''C!rc..k
...",pl).II..lres
Solifluction
deposits (t,-o<:eo)
over bas._till
(f.-alPn)
Soliflu(~:on
<:leaos;ts'(frOlen)
Over 4t.alion
till
Ld(Uslr''1I1S
(froz.en)
Tl!irracf!
OUIW<lsh deposits
Fp
Fpt
Ffg
Cs-'f
Bxu
GFe
GFo
Cs-f
GtO
GFk
L-f
Gte
°
L
Gtb-f
~
Gtb-f
Cs-f
FPI
Gtb-f
tlXU
Gtb-f
BUBTABK 5.02
:cfxu+Bxu
1hw+BXW
PHOTO INTERPRETATION
TERRAIN UNIT MAPS
I APD~f---::Ac-c:L:c-:A S-::-K:-A~P0c::-W=-=-E-::R=A-::UT--,Hc::-0::-cR::-::1Tc::-Y------j"Un~J SUSJTNA HYDROELECTRIC PROJECT
CH.APP.APf'
2000 4000 FEET==::a
REVISIONS.
o
ISCALE
;"~.1oS'C ,..,...,,,'!lll ....
lind ,'At...."
..,te,"t1ezltHU.l "'H}lla'"
fNInr'tl lICUI".!,'llt~.
RVSKaq
....~u~<Ir;lIlil.
groayw<l.(lo;.,.:>1 iii
,O-I'·ur-lTnd
11J1Ie.~I'I.Il;:ll~e.
r.l1.m.1.mt>f"l"'M'5M
-
~-
Cs-f
Glb-f
Bedrock
Moppinq
Units
Tv Tsu -Tbqd Tsmq TKgr Jom (Jtr)(Jqd)RV Pzv (Pis)Koq
Abbrevioted
Descriptions
T ~'''i'Y \lllIlc-anle
1""O'I:f..,~••",lIf0""
"'It1"J"r1 v«•.'1'QlN5,
""0 P""oc .sl'!;5;
~nyolll'C:Ie bill:t.U :;:.
,':1"1 llry ,"".!'II.'-,"'"
";t<lu'n""!Ilr-y -m::;"J;"
-on<g'om~~;,te.-'''''0:.:-
'-\OIH,.ilnd ~liyJ.IDn•.
I "nll)"y r'l>\lte 'Ten .II!"y l-4:11l"'il.
UIIJrn;;gIDf"I1~,'oc..1 m'ljiimill4 Ie jjl)~gnU'I.'le,
tlorr>gflf"l;1.<;if,UtOa,oQr'~.r~rll!",,{l~,"'c.I (h~rt-of
(Tt'l9d)(If ..tUr;tt;:niX:'
Tllrt Jiry all;J!flr
Cr.l~~t'CluS <;.1ratlil.i<..'
fonnlng \m,ll1 plulo.',
~'J'~I ..I';;..~~"It'-:;lIt~,
,r,<;;III'on.,.Cli or •..,-
-,:;n.H .$.1lUor:!-14:IC!lO.1
I r tl'l"ll1ll1ml!..-IJlr!..no
U'l"..'T!'=J1 ....rlfll \.'U;J11
r l:hlr ~••111Ic
Plt.l"...ot::;mll:I"!;KkiI
f(l"rl'1tt;:l ,n -,t'I.llo...
fILM/"It:""T...lro"O;f'111
l,He 1J,,1~:'Q1(0,,1,,';.,
.rrd llir;fJil:lfIlC m"la·
vOlu"O!i/llnlc Nx."!>,
1;,.f.161 .'JH<l-1 1"t:~'U"~
(PI~).
Crfl!.c«ous .tro.1hte
.'it\ti ;r"vw kl1l.(,~it
Itl't,_(Jllf<::nrDd
IUl"ultJllor .i.ItQUeft<.e,
u,...g""O~e 1TWiamorphl,-n
Tro,u,$l
"TIll :.IIH'
ttHII:U4O(
""",'lIlc ~I
Miscellaneaus Map Symbols
Scarp ~Slide Scar ;(\Tl ~j
Buried Channel Y Trail~///
Rock Contact r~/
,
1\
Solifluction
deposits (frozen)
over b<l$/JI till
((rozen)
L.<Icustrine
deposits over
basal till (frozen)
Lacustrine
sediments over
ablation tlll
Terrain
Unit
Name
Gr<Jf'\ular ,Jlluvi.ll
r.n
Kame deposits
Abl;,\ion till
Colluvial deposits
8dsill till (rrOlen)
Solifluction
deposits (frozen)
OrgClnic deposits
Solifluction
deposits (frozen)
over terrace
sediments
Lacu,trines
(frozen)
FrOlen b"sal till
over bedrock
Floodpl"in
deposits
CollUvium.over
wlO3th"red Qr
poorly Can.\-oli·
d<lled U4!droCk
Outwash deposits
,"oU...viul"ll over
t;;lj.r<Dck "nd
bedrock
e:-.pcluf*,t
SOlifluction
deposits (frozen)
over abl<ltion
till
A~oII\io"till
ovtr l,In-
WlJIl->en:d
bedrock
Unweathered,
consolidilled
bedrock
SOlifluction
d..-posits (frozen)
over bedrock
Cs-f
FP!
L-f
Cs-f
GtO
Fpt
Ffg
GFa
o
CI
Fp
Cs-f~
GFk
C
Cs-f
Gta
Bxu
GFe
Gtb-f
l3XU
L
Gtb-f
Cs-f
Gtb-f
"lOOnCT 052502
Q:oLU AUGUST 1981
Gtb-f
Terrain
Unit
Symbal
tfxu-+Bxu
~+BXW
BUBTASK !5.02
PHOTO INTERPRETATION
TERRAIN UNIT MAPS
CH.APP.APf'REVISIONS.
O~i........~2~O~O~O~~4~OOO FEETSCALE
RVS
~n"~Jlt rr-"~"hl'o~.ll
j ....c .."\".•n
111\(-<'r:lI'ld.-d u.,>l ()w
''1.I'",~~·e'l:J'C.I~'1
lC(':}US ....;;:;-dllh
~'..ywKke,0'a
~l",rortl,..d
1:11 •....CI;L.illtl~
·"a.I'fltHalMl""oh,,,.ItI
Kaq
Miscellaneous Map Symbals
Scarp ~Slide scar·;(\I'Buried Channel
~/~Trail/J
Koq
C .1,.(otOV.-;I"'~H.
~It.'!~."~'w"':",,,til III
,,..-"1.1~r>ntLCl
I "0 nlte ~IHIUllt'tl!.
'0\">':1'JOti'..t.I.-mc(":..n•.,.,.
Pzv (PIs)
,.:111 ..I'C':'C:"OlliilH C.
aliI).''t!.t'~I Ittllll'"
IOIUl"'ClQIOI"l',~..."
.~.....'fJ'Il'ltoi "'.~tcy.'lll
"-lSI.
RV
J .•r-'ll~Mr':T1I~
Iltll1"'oO"~cl ,::;riM"'''''
_t:MI~,',m ....(ll.:oJl;1l
IrGl"llllllll.lI .Ill ~I';:
jl.lol'lOlJ·I<!·,;",(''rJJ.
Jam (Jtr }(Jqd)
/
./
/
r--J
TKqr
Rock Contact
"rll,jj"y "'HI o;.r
.1'flt.'l"""-'<J''tJr.,11t;l:t
IQr1"I nO ,",.It fllulOn.
TsmqTbqd
T'-l atl"v 0 Olll~•.,••'..."n'll
QI"'IlTIo.""d "rte;'«JCd'...,~",,,l I ...rrf);"'A(tl~e .
t~..:)-"'r...J)ar.gr.,..Qa.Q~'le rotcr "'111'1 ..I •rPO'
(Tnac I.Dr ..'tll"r,;",t\~...
~.rl'.I"V rton''qil'''l,e
•(lC.rllllll"llu .....'·Ot.KS:
Gl"'I\I':rll·y.~..\e.u.uj-
slO".ana "ay~lgl'•.
-
Tsu _Tv
~.II,..ry \'Qlcenl(
roc ...~:Uli1l1ow
,1'1 ru~l~es rio ....).
,wd DyrllXl.,J,CS:
f1'lyaj,IIC 1C:C t1tu.llk..
Bedrock
Moppinq
Units
Abbreviated
Desc riptions
Terrain Terrain
Unit Unit
Symbol Name
Unweillthered,
Bxu consolid~led
hedrock
C C:olluviill deposiu
CI L.IIndslide
Cs·f :;olifluction
deposits (fronn)
Ffg C,...nul...alluviill'.n
Fp Floodplain
aeposiU
Fpt Terr.c.
GFo Oulw.nh depOSIts
GFe E.sker tJ~lJosils
GFk Kc\ml!depoSIts
Gfa Ab'<ltion lill
Gtb·f BaUl \ill (froun)
0 Org.llnic deposits
L·f lClcustrines
(frozen)
L Lacustrine
GiO sediments over
<tbla(ien till
_L_Lacustrine
deposits overGtb·f bds.1 till (fronn)
Cs·f Solifluction
depoSIts (frozen)
Gtb·f over bClSill t,lI
Uraz"n)
Cs·f SOlifluction
deposits Urozen)
GiO over IiIblillien
till
SolifluctionCs·f deposiu (frozen)
FPT over terrace
sediments
Cs.-f 501lfluction
deposits (frozen)BXU over bedr')c",
Gtb·f Frozen bas"l till
1JXU over Otldrock
A.blation till-~over vn-
weilthered
bearack
"Efxu+BxU
~~hJVIIJm over
oeot"CCK ilno
tledrock
I!xpOsures
~+BXW Col~"vium over
""'lIl1ler-eO or
poorly c.on:.ol,-
dale.a bedrook
1\
!I.D iii:aUBTAsK
PHOTO INTBRPRETATION
TERRAIN UNIT MAPS
~I---------i
CH.APP.APP.
2000 4000 FEET
:o:
REVISIONS.DATi
RVS
--f't~..·.110.....11
,,1"'1 :<'I1e ,.1\
ll",r~?o.d :,tl.llgw
.........."'J"."CA.
Kog
C"et.:.;lD()l,.~.rqUm.
..lJ g1'.\...."'t ...,.,vI '"
If'COl,Q"(t'rn-atJ
lurbld,:......ljl.l..nc;..
IO ....CI'·.d "·.I-.w.:-rUfll,m
Bedrock
Moppinq
Units
Abbreviated
Descriptions
Tv
T.,.-ll"ry Volc..nic
rDClu.)"nltllow
Inlru$,vIU.fIOw~.
..."d Qyr;r.;:llllirlcs;
,'nyQIIt"t 10 oaSd/(,C
Tsu -
TfT'IJ'''v 1\1>n·"'''''''.
..ltdll1"l."t.ry rOf,c.s:
a')"~31J1 ...ralc.lJlnd-
i'll"ot,',"n c <Il~"Ilb·'.,
Tbqd
T"rlUIIrV OIO(lt.
Ql"llr.ot:l.or,!e:Igc;.~1
t~OI"J'\t)I.l'Tde ".V.,;')Ot'J1orit
(Tngal.
Tsmq
Tert,,,.-y $CTIllt,
""Igrr'''llte .."d ",...rllle,
rII!:l"~s."'J'1"Ig lih.,~r
or •Ilt'QIl ,IOCIl,
TKqr
Tl!rll~ry .....,(1/0"-
Cr"tilt;'e..,ua ~r.,.lI(1CS
[pmllnlil ,mdH n-lll1.:n1.
Jam (Jtr)(Jqd)
JlJt ~UIC JI",PtlltH:I,:""
''''11'"rf 9rtoe...•
u;ll,.t j ·...rbl •.Ioc.JI
U''::orrClI/!'"l'ottlt iJI ..al'll'1
Qrll'lodlcl"U'"C"oJ0).
RV
r~~~:.';;w ......til;
""""0,,1'I~_C"rQ\:,",S
ll)r"T"IllO ,"1"."1)""
'fTII""lnlll e-(l""'l:!.,,,,,,"1
Pzv (PIs)
Ull'PillRie'.i:o,e \._1,
~,·OI1Ulhl:."'f'l,,-
IrJr~Jl/oog.n,c .c:-........
1l)t:,A1 ll"'f:l.~I'mlll$lt,n •
(PI...,.
Kaq
~nrUi ~:>•.a ..r~n,:..
and ~r"v",,,("1<,#I.1;1
Ul'c:.oOI:lI"'J'TfI4Id
lur-tl·alc.:1I'q.,.,f'1COl.
IlJl'o'g'""'JI:!ptIHn.~.t:~"·"ln
't,......
l",r.~1I
"l.rt>.l
"'4iI'IIUI
Miscellaneous Map Symbols
Scarp ~Slide scar;(\TT
~/
Buried Channel 9 Trail /~./
,052502
~...,.AUGUST 1981
BUBTAIIK 15.0a
PHOTO INTERPRI!TATION
TERRAIN UNIT MAPS
Terrain Terrain
Unit Unit
Symbol Nome
Unweathered ,
Bxu consolidated
bedrock
C Colluvial!deposits
CI Landslide
Cs-I Solifluction
deposits (frozen)
FIg Granular "Uuv,al'.n
Fp Floodpl.-in
deposits
Fpt Terracll
GFo Outw.uh deposits
GFe Esker deposit!>
GFk Kame deposits
Gto Ablati(ln Jill
Gtb-f II.~;)I lit \"'t'lc:nl
0 Organic deposits
L-f Lltt:uslrtnes
(ft"'Cl..I"I)
L Llto:ll.ulrine
GtO $e,[hrr.,.,ts over
.m[.tt,on till
L ~"_l.stdne
ClIJposiu over
Glb·f ~....I 111 ('¥ozen)
£§.:l...Sg,lif!ucllon
d.pos'11 (Ir:nen)
Gtb·f over b ....1 tlll
(trozen)
Cs·f smirluct.~n
d~~sits (I~.:en)
GtO (!ve,.aDLII!I:;>u
1111
~linU('litlnCs-I deposiu (rl"Qzen)
FPT ov,'~te"...,:e
Ud,m."ts
Cs·f li'IlJt'ti~fl
Bxu dOp(l"U l·....turn)
over I)oIIl;Sr(:lCI<.
Gtb-I Frozen bllUI till
trXU over cedr.:x;k
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APPENDIX K
RESERVOIR GEOLOGY
APPENDIX K
RESERVOIR SLOPE STABILITY
1 -INTRODUCTION
1.1 -General
Impounding of the Susitna River valley a.nd its tributaries will influ-
ence the slope stabi 1 ity of both the Devi 1 Canyon and Watana Reser-
voirs.Currently on the slopes above river elevation there is evidence
of shallow landsl ides and discontinuous permafrost.Impounding of
water will result in raising the groundwater table and thawing the per-
mafrost which will likely cause slope instability and failures within
certain areas of the reservoirs.
Because of the complexity and uncertainties of analyzing slope stabili-
ties in a thawing permafrost environment,a "best estimate"has been
made in this study to identify those areas in the reservoir that may be
subject to future beaching,erosion,and slope failures.
The following sections discuss slope stability as it relates to the
Watana and Devil Canyon reservoirs.Section 2 briefly discusses the
type and causes for slope instabil ity while Section 3 and 4 evaluate
the type of instability that may occur after impoundment at Watana and
Devil Canyon.The last two sections provide a summary and conclusions
with recommendations.
2 -TYPES AND CAUSES OF SLOPE INSTABILITY
2.1 - Gener a1
Shoreline erosions will occur as a result of two geologic process:(1)
beachi ng and (2)mass movements.The types of mass movement encoun-
tered in a permafrost terrain and which are pertinent to this study are
described below (4,5,12):
(a)Bimodal Flow - A slide that consists of a steep headwall contain-
ing ice or ice-rich sediment,which retreats in a retrogressive
fashion through melting forming a debris flow which slides down
the face of the headwall to its base.
(b)Block Slide -Movement of a large block that has moved out and
down with varying degrees of back tilting,most often along a pre-
existing plane of weakness such as bedding,joints,and faults.
(c)Flows - A broad type of movement that exhibits the characteristics
of a viscous fluid in its downslope motion.
K-1
(d)Multiple Regressive Flow -Forms a series of arcuate,concave
downslope ridges as it retains some portion of the prefailure
rel i ef.
(e)Multiple Retrogressive Flow/Slide -Series of arcuate blocks con-
cave towards the toe that step backward higher and higher towards
the headwa 11.
(f)Rotational Slides - A landslide in which shearing takes place on a
well defined,curved shear surface,concave upward in cross sec-
tion,producing a backward rotation in the displaced mass.
(g)Skin Flows -The detachment of a thin veneer of vegetation and
mineral soil with subsequent movement over a planar,inclined sur-
face,usually indicative of thawing fine-grained overburden over
permafrost.
(h)Slides -Landslides exhibiting a more coherent displacement;a
greater appearance of rigid-body motion.
(i)Solifluction Flow -Ground movements restricted to the active lay-
er and generally requires fine-grained soils caused by melting and
saturated soils.
Aside from the formation of beaches due to erosion,instability along
the reservoir slopes can result from two principal causes:a change in
the groundwater regi me and the thawi ng of permafrost.Beach eros ion
can give rise to general instability through the sloughing or failure
of an oversteepened backslope,thereby enlarging the beach area.
2.2 -Changes in Groundwater Regime
As a reservoir fills,the groundwater table in the adjacent slope also
rises as shown in Figure 2.1.This may result in a previously stable
slope above the groundwater table to become unstable due to increased
pore pressures and seepage acting on the slope.The slope shown in
Figure 2.1,whether in soil or rock,is less stable after filling than
it was prior to the existence of the reservoir.This is not to say
that this slope will necessarily fail,si'nce failure is dependent on
the strength parameters of the soil or the rock.
Rapid drawdown of a reservoir may also result in increased instability
of susceptible slopes.
2.3 -Thawing of Permafrost
The instability of thawing slopes in permafrost is addressed by
McRoberts and Morgenstern (4).They i ndi cate that the characteri st ic
features of solifluction slopes,skin flows and the lobes of bimodul
flows are caused by instability on low angle slopes resulting from
thawing of permafrost.Mobility is often substantial and rapid as the
movements are generally distributed throughout the mass.
K-2
2.4 -Stability During Earthquakes
There are certain conditions which can exist after reservoir filling
which will cause slides to occur during earthquakes.This section will
address only those situations which may exist after reservoir filling
in which slopes are more susceptible to sliding under earthquake load-
ing than they are in their present condition.
Submerged slopes in granular materials,particularly uniform fine
sands,may be susceptible to liquefaction during earthquakes.This is
one example where a small slide could occur below the reservoir level.
In addition,areas above the reservoir rim in which the groundwater
table has re-establ ished itself could have a greater potential for
sl iding during an earthquake due to the increased pore water pres-
sures.
Thawing permafrost could generate excess pore pressures in some soils.
In cases where this situation exists in liquefiable soils,small slides
on flat lying slopes could occur.The existence of fine-grained sands,
coarse silts and other liquefaction susceptible material is not exten-
sive in the reservoir areas.Therefore,it is considered that the ex-
tent of fa il ures due to 1i quefact ion dur i ng earthquakes wi 11 be sma 11
and primarily limited to areas of permafrost thaw.Some slides could
occur above the reservoir level in previously unfrozen soils due to the
earthquake shaking.
2.5 -Slope Stability Models for Watana and Devil Canyon Reservoirs
Following a deta-iled evaluation of the Watana and Dev"il Canyon reser-
voir geology,four general slope stability models were defined for this
study.These models are shown in Figures 2.2 and 2.3 and consist of
several types of beaching,flows and slides that could occur in the
reservoir duri ng and after impoundment.Based on aeri a1 photo -j nter-
pretation and limited field reconnaissance,potentially unstable slopes
in the reservoir were classified by one or more of these models as to
the type of failure that may occur in specific areas.In addition to
identifying potential slope instability models around the reservoir,
attempts were made to delineate areas of existing slope failures,and
permafrost regions.These maps are shown in Figures 2.4 through 2.28.
Table K.1 provides a summary of soil types as they relate to the type
of slope instability.As stated above,these maps have been construct-
ed using photo interpretation and limited field reconnaissance and are
intended to be preliminary and subject to verification in subsequent
stUdies.
3 -DEVIL CANYON RESERVOIR
3.1 -Surficial and Bedrock Geology
The topography in and around the Devi 1 Canyon reservoir is bedrock con-
trolled.Overburden is thin to absent,except in the upper reaches of
the proposed reservoir where alluvial deposits cover the valley floor.
K-3
A large intrusive plutonic body composed predominantly of biotite gran-
odiorite with local areas of quartz diorite and diorite,underlies most
of the reservoir and adjacent slopes.The rock is light gray to pink,
medium grained and composed of quartz,feldspar,biotite and horn-
blende.The most common mafic mineral is biotite.Where weathered,
the rock has a light yellow-gray or pinkish yellow-gray color,except
where it is highly oxidized and iron stained.The granodiorite is gen-
erally massive,competent,and hard with the exception of the rock ex-
posed on the upland north of the Susitna River where the biotite grano-
diorite has been badly decomposed as a result of mechanical weather-
i ng.
The other principal rock types in the reservoir area are the argillite
and graywacke,which are exposed at the Devil Canyon damsite.The ar-
gillite has been intruded by the massive granodiorite and as a result,
large isolated roof pendants of argillite and graywacke are found
locally throughout the reservior and surrounding areas.The argillite/
graywacke varies locally to a phyllite of low metamorphic grade,with
possible isolated schist outcrops.
The rock has been isoclinally folded into steeply dipping structures
which generally strike northeast-southwest.The contact between the
argillite and the biotite granodiorite crosses the Susitna River just
upstream of the Devil Canyon damsite.It is non-conformable and is
characterized by an aphanitic texture with a wide chilled zone.The
trend of the contact is roughly northeast-southwest where it crosses
the ri ver.Several large outcrops of the argill ite completely sur-
rounded by the bi ot ite granodi orite are found withi n the Devi 1 Creek
area.
A general discussion of the regional geology is presented in Section
4.1 of the main text.
3.2 -Slope Stability and Erosion
The Devil Canyon reservoir will be entirely confined within the walls
of the present river valley.This reservoir will be a narrow and deep
wi th mi nima 1 seasonal drawdown.From Devil Canyon Creek downstream to
the damsite,the slopes of the reservoir and its shoreline consist
primarily of bedrock with localized areas of thin vaneer of colluvium
or till.Upstream of Devil Canyon Creek,the slopes of the reservoir
are covered with increasing amounts of unconsolidated materials,espe-
cially on the south abutment.These materials are principa ly basal
tills,coarse-grained floodplain deposits,and alluvial fan deposits
(see Appendix J).
Existing slope failures in this area of the Susitna River,as defined
by photogrammetry and 1 imited fi e1d reconna i ssance,are sk in and bi-
modal flows in soil and block slides and rotational slides in rock.
The basal tills are the primary materlals susceptible to mass move-
ments.On the south abutment there is a possibility of sporadic perma-
frost existing within the delineated areas.Upstream of this area
K-4
the basal till is nearly continuously frozen as evidenced by field in-
formation in Borrow Area H.
Downstream of the Devil Creek area,instability is largely reserved to
small rock falls.Beaching will be the primary process acting on the
shoreline in this area (Figures 3.1 and 3.2).Although this area is
mapped as a basal till,the material is coarser grained than that which
is found in the Watana Reservoir and is therefore more susceptible to
beaching.
In areas where the shore 1i ne wi 11 be in contact wi th steep bedrock
cliffs,the fluctuation of the reservoir may contribute to rockfalls.
Fluctuation of the reservoir and therefore the groundwater table,ac-
companied by seasonal freezing and thawing,will encourage frost heav-
i ng as an eros i ve agent to accelerate degradati on of the slope and
beaching.These rock falls will be limited in extent and will not have
the capacity to produce a large wave which could affect dam stability.
In Devil Creek,a potential small block slide may occur after reservoir
or dam.
Above Devil Creek up to about river mile 180,beaching will be the most
common erosive agent.Present slope instability above reservoir normal
pool level will continue to occur,with primary beaching occurring at
the shoreline.At approximate river mile 175,there is an old land-
slide on the south abutment.This large rotational slide is composed
of basal till which,for the most part,is frozen.A large bimodal
flow exists within this block headed by a large block of ground ice.
Year 1y ab 1at i on of the ice results in flowage of saturated materi a1
downslope.The 1ands1 i de has an arcuate back scarp whi ch has become
completely vegetated since its last movement.However,this landslide,
which has an estimated volume of 3.4 mcy,could possibly be reactivated
due to cont i nued thawi ng or change in the groundwater regime brought
about with reservoir filling.
Since the maximum pool elevation extends only to the toe of this slide,
it is unlikely that a large catastrophic slide could result from normal
reservoir impoundment (See Figure 3.3).However,potential for an
earthquake-induced landslide is possible.A mass slide in this area
could result in temporary blockage of river flow.
The distance from the dam,the meandering of the river valley,and the
shallow depth of the reservoir in this area makes the potential of a
wave induced by a massive landslide that could affect the dam stability
very remote.
In general,the following conclusions can be drawn about the slope con-
ditions of the Devil Canyon Reservoir after impoundment:
-Minimal drawdown of the reservoir is conducive to stable slope condi-
tions.
K-5
-The lack of significant depths of unconsolidated materials along the
lo\'/er slopes of the reservoir and the exi stence of stabl e bedrock
conditions is indicative of stable slope conditions after reservoir
impounding.
An old large landslide in the upper reservoir has the potential for
instability,which,if failed,could conceivably create a temporary
blockage of the river in this area.
The probability of a landslide-induced wave in the reservoir over-
topping the dam is remote.
4 -WATANA RESERVOIR
4.1 -General
Preliminary reconnaissance mapping of the Watana Reservoir was perform-
ed during this study and principal rock types and general types of sur-
ficial material were identified.
The topography of the Watana Reservoir and adjacent slopes is charac-
terized by a narrow V-shaped stream-cut valley superimposed on a broad
U-shaped glacial valley.Surficial deposits mask much of the bedrock
in the area,especially in the lower and uppermost reaches of the
reservoir.A surficial geology map of the reservoir,prepared by the
COE,and airphoto interpretation performed during this study (Appendix
J),identifies tills,lacustrine and alluvial deposits,as well as pre-
dominant rock types (11).
4.2 -Surficial Deposits
Generally,the lower section of the Watana Reservoir and adjacent
slopes are covered by a vaneer of glacial till and lacustrine deposits.
Two main types of till have been identified in this area;ablation and
basal tills.The basal till is predominately over-consolidated,with a
fine-grain matrix (more silt and clay)and low permeability.The abla-
tion till has less fines and a somewhat higher permeability.Lacus-
trine deposits consist primarily of poorly-graded fine sands and silts
with lesser amounts of gravel and clay,and exhibits a crude stratifi-
cation.
On the south side of the Susitna River,the Fog Lake area is character-
istic of a fluted ground moraine surface.Upstream in the Watana Creek
area,glaciolacustrine material forms a broad,flat plain which mantles
the underlying glacial till and the partially lithified Tertiary sedi-
ments.Significant alluvial and outwash deposits exist in the river
valley.Ice disintegration features such as kames and eskers have been
observed adjacent to the river valley.
K-6
Permafrost exists in the area,as evidenced by ground ice,patterned
ground stone nets and slumping of the glacial till overlying perma-
frost.Numerous slumps have been identified in the Watana Reservoir
area,especially in sediments comprised of basal till.Additional
details regarding this subject will be given in subsequent sections.
In addition,numerous areas of frozen alluvium and interstitial ice
crystals have been observed in outcrops and identified from drill hole
drive samples.
4.3 -Bedrock Geology
As discussed in Section 6 (Main Report),the Watana damsite is under-
lain by a diorite pluton.Approximately three miles upstream of the
Watana damsite,a non-conformable contact between argill ite and the
dioritic pluton crosses the Susitna River.An approximate location of
this contact has also been delineated on Fog Creek,four miles to the
south of the damsite.Just downstream of the confluence of Watana
Creek and the Susitna River,the bedrock consists of semi-consolidated,
Tertiary sediments (8)and volcanics of Triassic age.These Triassic
volcanics consist of metavolcaniclastic rocks and marble (3).From
just upstream of Watana Creek to Jay Creek,the rock consists of a
metavo 1canogeni c sequence domi nant ly composed of met amorphosed flows
and tuffs of basaltic to andesitic composition.From Jay Creek to just
downstream of the Oshetna River,the reservoir is underlain by a meta-
morphic terrain of amphibolite and minor amounts of greenschist and
foliated diorite.To the east of the Oshetna River,glacial deposits
are predomi nant.
The main structural feature within the Watana Reservoir is the Talkeet-
na Thrust fault,which trends northeast-southwest (3)and crosses the
Susitna River approximately eight miles upstream of the Watana damsite
(Figure 4.1 -Main Text).Csejtey and others (2)have interpreted this
to have a southeast dip,while Turner and Smith (10)suggest a north-
west dip.The southwest end of the fault is overlain by unfaulted
Tertiary volcanics (2).A detailed discussion of this fault is pre-
sented in Woodward-Clyde Consultant's Task 4 Report.A general discus-
sion of regional geology is presented in Section 4 of the main text.
4.4 -Slope Stability and Erosion
Most of the slopes within the reservoir are composed of unconsolidated
materials.As a generalization,permafrost is nearly continuous in the
basal tills and sporatic to continuous in the lacustrine deposits.In
Figures 2.12 through 2.28,the distribution of permafrost has been de-
lineated primarily on the flatter slopes below elevation 2300 feet.
Inclined slopes may be underlain by permafrost,but based,on photogra-
metric characteristics,the active layer is much thicker indicating
that permafrost soi ls are thawing,and/or that permafrost does not
exist.Existing slope instability within the reservoir (as defined by
aerial photographic interpretation (Appendix J)and limited field re-
connaissance),indicate that the types of mass movement are primarily
K-7
solifluction,skin flows,bimodal flows,and small rotational slides.
These types of failure occur predominantly in the basal till or areas
where the basal till is overlain by lacustrine deposits (Appendix J).
In some cases,solifluction,which originated in the basal till has
proceeded downslope over some of the floodplain terraces.
Three major factors which will contribute significantly to slope in-
stabi 1 ity in the Watana Reservoir are changes in the groundwater
regime,large seasonal fluctuation of the reservoir level (estimated at
60 feet),and thawing of permafrost.These factors were analyzed to
determine their effects on typical conditions in the reservoir.From
this,four basic models of shoreline conditions were developed (Figures
2.2 and 2.3).The two processes affecting the shoreline of the reser-
voirs are beaching and slope stability.lhese models were applied to
selected reaches of the reservoir shoreline and evaluated for condi-
tions at or near normal pool levels.It should be noted that the slope
stability of the Watana Reservoir was evaluated for the "worst"case
which considered the maximum and minimum pool levels.In cases where
sliding wHl occur,it will not be uncommon for some flows or possibly
beaching to occur over the same reach.Slope instabil ity during and
after reservoir impounding will be addressed below.
It is estimated that filling of the reservoir to normal pool level will
take approximatel'y three years.Due to the relatively slow rate of
impounding,the potential for slope instability occurring during flood-
ing of the reservoir will be minimal and confined to shallow surface
flows and possibly some sliding.Slopes win be more susceptible to
slope i nstabil ity after impoundment when thawi ng of the permafrost
soils occurs and the groundwater regime has reestablished itself in the
frozen soils.
Near the damsite,assumi ng that the present contours wi 11 remai n un-
changed,the north abutment wi 11 primarily be subject to beaching
except for some small flows and slides,which may occur adjacent to
Deadman Creek.On the south abutment,thawing of the frozen basal
tills will result in numerous skin and bimodal flows.There is also a
potential for small rotational sliding.to occur primarily opposite
Deadman Creek.
On the south abutment between the Watana dams ite and Vee Ca nyon,the
shoreline of the reservoir has a high potential for flows and shallow
rotational slides (Figures 4.1 and 4.2).In contrast to the north
abutment,the shoreline is almost exclusively in contact with frozen
basal tills,overburden is relatively thick,and steeper slopes are
present.Thermal erosion,resulting from the erosion and thawing of
the ice-rich fine grained soils,will be the key factor influencing
their stability.On the north abutment below Vee Canyon and on both
abutments upstream of Vee Canyon,the geological and topographic condi-
tions are more variable and therefore have a potential for varying
slope conditions.In the Watana Creek drainage area,there is a thick
sequence of lacustrine material overlying the basal till (Figure 4.3).
K-8
Unlike the till,it appears that the lacustrine material is largely un-
frozen.All four types of slope instability could develop here,de-
pendi ng on where the seasonal drawdown zone is in contact with the
aforement i oned strat i graphy.In addi t ion,slope i nstabi 1i ty resul t i ng
from potential liquefaction of the lacustrine material during earth-
quakes may occur.Overall,slopes on the north abutment,in contrast
with the south abutment,are less steep and slightly better drained,
which may be indicative of less continuous permafrost and/or slightly
coarse material at the surface with a deeper active layer.
In general,the potential for beaching 'is high due to:(a)the wide
seasonal drawdown zone that will be in contact with a thin vaneer of
colluvium over bedrock;and,(b)the large areas around the reservoir
with low slopes (Figure 4.4).In the Oshetna-Goose Creeks area,there
is a th i ck sequence of 1acustr i ne materi a 1.Permafr ost appears to be
nearly continuous in this area based on the presence of unsorted
polygonal ground and potential thermokarst activity around some of the
many small ponds (thaw lakes/kettles).The reservoir in this area will
be primarily confined within the floodplain and therefore little
modification of the slopes is expected.Where the slopes are steep,
there could be some thermal niche erosion resulting in small rotational
slides.
The potential for a large block slide occurring,and generating a wave
which could overtop the dam is very remote.For this to occur,a very
high,steep slope with a potentially unstable block of large volume
would need to exist adjacent to the reservoir.This condition was not
observed withi n the limits of the reservoir.In approximately the
fi rst 16 mi 1 es upstream of the dam,the shore 1i ne wi 11 be in contact
with the low slopes of the broad U-shaped valley.Between 16 and 30
miles upstream of the dam,no potentially large landslides were
observed.Beyond 30 Illi 1es upstream,the reservoir begi ns to meander
and narrows,therefore any wave induced in this area by a large land-
slide would,in all likelihood,dissipate prior to reaching the dam.
In general,the following conclusions can be drawn about the slope con-
ditions of the Watana reservoir after impounding:
-The principal factors influencing slope instability are the large
seasonal drawdown of the reservoir and the thawing of permafrost
soils.Other factors are the change in the groundwater regime,the
steepness of the slopes,coarseness of the material,thermal toe
erosion,and the fetch available to generate wave action;
The potential for beaching is much greater on the north abutment of
the reservoir;
A large portion of the reservoir slopes are susceptible to shallow
slides,mainly skin and bimodal flows,and shallow rotational
slides;
K-9
-The potential for a large block slide which might generate a wave
that could overtop the dam is remote;and
-The period in which restabi1ization of the slopes adjacent to the
reservoir will occur is largely unknown.
In general,most of the reservoir slopes wi 11 be totally submerged.
Areas where the filling is above the break in slope will exhibit less
stability problems than those in which the reservoir is at an interme-
diate or low level.Flow slides induced by thawing permafrost can be
expected to occur over very flat-lying surfaces.
5 -'SUMMARY
Some amount of slope instability will be generated in the Watana and
Devi 1 Ca nyon reservoirs due to reservoir fi 11 i ng.These areas wi 11
primarily be in locations where the water level will be at an interme-
diate level relative to the valley depth.
Slope failure will be more common in the Watana reservoi r due to the
existence of permafrost soil throughout the reservoir.The Devil Can-
yon reservoir is generally in more stable rock and the relatively thin
overburden is unfrozen in the reach of the ri ver upstream from the
dam.
Although skin flows,minor slides and beaching will be common in parts
of the reservoirs,it will present only a visual concern and poses no
threat to the project.Many areas in which sl iding does occur wi 11
stabilize into beaches with a steep backs10pe.
Tree root systems left from reservoir clearing will tend to hold shal-
low surface slides and in cases where permafrost exists may have a
stabilizing influence since the mat will hold the soil in place until
excess pore pressure have dissipated.
6 -RECOMMENDATIONS
It is recommended that typical slope conditions out1ined in this report
be further investigated during subsequent phases of the project in
order to determine:
-The magnitude of the potential for instability at a given location;
and
-Whether beaching or sliding will exist at major migrating herd cross-
i ng sites.
K-lO
This investigation should include drilling,instrumentation and labora-
tory analysis to confirm the findings in this study.Since only one
significant existing landslide has been identified in this study,it is
also recommended that further study be directed to this site to deter-
mine the potential for future sliding in this area.
K-ll
TABLE K.1:CHARACTERISTICS OF SLOPE MATERIALS
Unit
Bedrock
Colluvium,over
bedrock and bedrock
exposures
Floodplain
Floodplain Terraces
Granular Alluvial Fan
Kame Deposits
Lacustrine
Basal Till
Terrain Unit
Symbol""
Bxu
C +Bxu
Bxu
Fp
Fpt
Ffg
GFK
L
Gtb-f
Mater ial
Consolidated bedrock
Angular blocks of rock with some
sand and silt overlying bedrock
Rounded cobbles,gravel and sand
sorted and layered with or without
silt cover
Rounded cobbles,gravel and sand
with some silt covered by thin silt
layers.Sorted,layered
Rounded cobbles,gravel,with sand
and some silt.Some sorting and
layering of materials
Rounded and striated cobbles and
sand.Crudely sorted and layered
Fine sand to sandy silt with
occasional pebbles.Sorted and
layered
Gravelly silty sand and gravelly,
sandy silt cobbles and boulders
poorly rounded and striated.No
layering,poorly graded
Slope Cona it l.Ons
Permafrost I Current Slope After Reservoir Filling
Condit ions Stabilit Low Stee
unfrozen I stable Beaching (1)**
unfrozen stable Beaching (I)
unfrozen stable Beaching
Lnfrozen I stable I Beaching (1)
mfrozen I stables I Beach ing (I)
unfrozen I stable I Beaching (1)
unfrozen I st able I Beaching (I)Slid ing (II 1)
frozen stable Flows (II)Sliding (IV)
frozen I unstoole I Flows (I 1)Sliding (IV)
Ablat ion Till
Ablation till over
unweathered layer
Gta
Gta
"BrU
Rounded and striated cobbles,
gravel and sand,no layering,well
graded.Boulder and cobble,lag
covers surface
Rounded and striated cobbles,
gravel and sand,no layering,well
graded over bedrock
unfrozen
frozen
unfrozen
stable
st able
stable
Beaching (I)Sliding (IV)
Flow (II)Sliding (IV)
Beaching (1)
""See Appendix J for mapped terrain unit sylTtJols.
**1,II,III,IV -refer to Figures 2.2 and 2.3.
REFERENCES AND BIBLIOGRAPHY
1.Brown,W.G.,and Johnston,G.H.,"Dikes and Permafrost:Predicting
Thaw and Settlemene,Canadian Geotechnica1 Journal,Vol.7,
pp.365-371,1970.
2.Csejtey,B.Jr.,Foster,H.L.,and Nokleberg,W.J.,"Cretaceous
Accretion of the Talkeetna Superterrane and Subsequent Devel-
opment of the Denali Fault in Southcentral and Eastern
Alaska",Geological Society of America,Abstract with Pro-
grams,p.409,1980.
3.Csejtey,B.Jr.,Nelson,W.H.,Jones,D.L.,Silberling,N.J.,Dean,
R.M.,Morris,M.S.,lamphere,M.A.Smith,J.G.,and Silberman,
M.L.,"Reconnaissance Geologic Map and Geochronology,Tal-
keetna Mountain Quadrangle,Northern Part of Anchorage Quad-
rangle,and Southwest Corner of Healy Quadrangle,Alaska,U.S.
Geological Survey,Open File Report 78-588A,p.60,1978.-----
4.Johnston,G.H.(ed.),Permafrost Engineering Design and Construc-
tion,John Wiley and Sons,1981.
5.McRoberts,E.C.,and Morgenstern,N.R.,"The Stability of Thawing
Slopes",Ca.nadian Geotechnical Journal,Vol.11,No.4,pp.
447-469,1974.
6."Stability of Slopes in Frozen Soil,Mackenzie Valley,N.W.T.",
Canadian Geotechnical Journal,Vol.11,pp.554-573,1974.
7. Newbury,R.W.,Beaty,K.G.,and McCullogh,G.K.,"Initial Shoreline
Eros ion ina Permafrost Affect Reservoi r,Southern 1ndi an
Lake,Canada",in North American Contribution to The Third
International Conference on Permafrost,Edmonton,Alberta,
National Academy of Sciences,Washington,pp.833-839,1978.
8.Smith,LE.,"Regional Geology of The Susitna-MacLaren River Area",
Alaska Division of Geological and Geophysical Surveys,Annual
Report,p.356,1974.
9.Smith,I.E.,Bundtzen,ToK.,and Trible,T.C.,"Stratabound Copper-
Gold Occurrence,Northern Talkeetna Mountains",Alaska DiVi-
sion of Geolo ical and Geo h sical Surve s,0 en File Re art
E,p.1 ;19 5.
10.Turner,D.L.,and Smith,I.E.,"Geochronology and Generalized Geo-
logy of the Central Alaska Range,Clearwater Mountains,and
Northern Talkeetna Mountains",Alaska Division of Geological
and.Geophysical Surveys,Open File Report 72,p.11;1974.
REFERENCES AND BIBLIOGRAPHY (Cont'd)
11.U.S.Army Corps of Engineers,Upper Susitna River Basin,Alaska,
Hydroelectric Power Supplemental Feasibility Report,1979.
12.Varnes,D.J.,"Landslide Types and Processes",in Eckert,E.B.,
(ed.),Landslides and Engineering Practice,-Highway Reserve
Board Special Report No.29,p.20-45,1958.
NEW GROUND WATER TABLE
'""
RESERVOIR LEVEL
RIVER
..,...
RIVER
POTENTIAL FAILURE SURFACE
_CD SURFACE
ORIGINAL GROUND WATER TABLE
o 500 1000 FEET
SCAL E ~i~~~~~~;;;;;;;;;;;;;;;~
TYPICAL SLOPE FAILURE
FIGURE 2.1 m
BEACHING (I)
BEACHING (I)
MINOR
INITIALLY
-
AFTER SEVERAL
,;,FLOWS (II)
.,,:.',..::0,
~?;'J·02
Q'.?.'~,,,.o···'....o.,,.0,,..,?:"~''''''
.,">.~.-.;..:.'r-.
,,
SLOPE
AND
MODELS FOR
DEVIL CANYON
TH
RE
'EARS
'.'00,
I
I
E WATANA
SERVOIRS
I
-
ASSUMPTIONS:
FLAT SLOPES.
COARSE GRAINED DEPOSITS OR UNFROZEN
TILL AND LACUSTRINE DEPOSITS.
STEEP BEDROCK SLOPES.
FLUCTUATION OF RESERVOIR AND
GROUNDWATER TABLE CAUSES FROST
WEDGING TO OCCUR CAUSING ROCKFALL.
FLAT SLOPES.
"""GENERALLY FINE GRAINED DEPOSITS,
FROZEN.
FIGURE 2.2
INITIALLY AFTER SEVERAL
"·"'·S~~n}1:.\'::·
,"",.,,'
.~:,·0'
,.,.:."
(JIT)SLI DING
SLIDING (I~[)
.,"...,
.',.flo',
',0'C ",~';,1 ••
."'.....<>.'.";.'.r'·'
.......,.
.,
o •
Q"•••' •~
.,',0'
(rl)
THE
RESE
MODELS FOR
CANYON
SLOPE
AND DEVIL
'(EARS
~;ff:?!:~.;···:;:···'~···'·:
~- .'.'•'.-0'"
WATANA
tVOIRS
-
ASSUMPTIONS:
STEEP SLOPES.
TWO LAYER CASE,LOWER LAYER IS FINE
GRAINED AND FROZEN.UPPER LAYER IS
COARSER GRAINED,PARTLY TO COMPLETELY
FROZEN.
FLOWS IN LOWER LAYER ACCOMPANY SLOPE
DEGRADATION
STEEP SLOPE:S.
FINE GRAINED AND UNFROZEN.
STEEP SLOPES.
FINE GRAIN~D AND UNFROZEN.
NOTE:POSSIBLE FURTHER SLIDING IF THAW
BULB EXTENDS INTO SLOPE WITH TI ME.
FIGURE 2.3
WATANA lWiI
FIGURE 2.12
\
\
FIGURE 2.10
".~
"'-
----:)Jx~'\()~r".~O
DEVIL CANYON RESERVOIR
INDEX MAP
250
'<I~tJ c.~~~-
'(-)
!-.-
\"'-,I
,~..,..-..../
~.--_/
/../
./WATANA RESERVOIR
\
:lURE 2.8
LOCATION MAP
-
SCAU:O 4~i~~§iiiiiiii..l8 MILES
-----.--NORMAl MAXIMUM
OPERATING lEVEL
El.14!l!l
-----ZooO ~CONTOUR IN FEET
A80VE MSl
SCALE:0,,;~~§iiiiiiiiiiii~Z MilES
-!
ERVOIR
FIGURE 2.4
........'t
\
,
\
/
t .........
.J
·.....
"-...
.',..
C'ANYON.'."
"
...."
,',
!.../
"\..'
\,
"
'.
""'"
,'"'...•'/""
I I
/
I·:
/
DEVI L CANYON
SLOPE STAB·ILlTY MAP
AREAS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY:
!
1I
m
III
III
Imr>
r-n
A A
tJ
o
BEACHING
FLOWS
SLIDING (UNFROZEN)
SLIDING I PERMAFROST)
DENOTES AREA EXTENT AND TYPE OF INSTABILITY
PRIMARY BEACHING INSTABILITY WITH SOME
POTENTIAL SLIDING
BEACHING AND FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
RIVER MILES
SECTION LOCATION
AREA OF POTENTIAL PERMAFROST
-.
I.REFER m FIGURES 2.2 AND 23 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABILITY MODELS
2 NO OELiNEATION OF PERMAFROST AREA ABOVE EL EVATION
2300 FEET
1 AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION AND WILL REOUIRE
FUTURE VERIFICATION.
o 1000 2000 FEET
SCALE ~E--~~_~~!
,NYON
JTY MAP
FIGURE 2.5
~..,
'..,'.'.
"',.~
,.-.~':<,
,..'''':\.,
".~..~
'.\\"
~-,,'-~-/~;~~'-~~-"~"':~...;f'.-.,../:-....c=,
.·····V~1/·..,.
I
D AREAS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY:
I REFER TO FIGURES 22 ANO 23 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABILITY MODELS
2 NO DELINEATION OF PERMAFROST AREA ABOVE ELEVATION
2300 FEET
AREAS OF POTENTIAL PERMAFROST BASEO PRINCI PALL Y
ON AIR PHOTO INTERPRETATION ANO WILL REQUIRE
FUTURE VERIFICATION
I
1I
m
llZ:
III
r (Il[)
r-n
A A
tot
BEACHING
FLOWS
SLIDING (UNFROZEN)
SLIDING (PERMAFROST)
DENOTES AREA EXTENT AND TYPE OF INSTA81l1TY
PRIMARY BEACHING INSTABILITY WtiH SOME
POTENTIAL SLIDING
BEACHING AND FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
RIVER MILES
SECTION LOCATION
AREA OF POTENTIAL PERMAFROST
oc.~~~10~O~0~_~20~OO FEETSCALEE.
NYON
.ITY MAP
FIGURE 2.6
"t'·-·
r ;171 --lD~,~l-;~--L-'I
DEVI L CANYON
SLOPE STABILITY MAP ;
D AREAS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY:
r
1I
]I
Jll
III
I (Il[I
I'U
,
A A
t.t
o
BEACHING
FLOWS
SLIDING (UNFROZEN)
SLIDING (PERMAFROST)
OENOTES AREA EXTENT ANO TYPE OF INSTABILITY
PRIMARY BEACHING INSTABILITY WITH SOME
POTENTIAL SLIDING
BEACHING ANO FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
RIVER MILES
SECTION LOCATION
AREA OF POTENTIAL PERMAFROST
'/1I~
r
\~J 'I',<II'
".'".;~.,.ofr;1"")/.
~~--~'..t/
"j"
'ff>.:..-./"r 1-=~-~/I
~NYON
_ITY MAP
I.REFER TO FIGURES 2.2 AND 23 FOR DETAILED
DESCRIPTION OF TYPE Of SLOPE INSTABILITY MODELS
2 NO DELINEATION CF PERMAFROST AREA ABOVE EL EVATION
2300 FEET
3.AREAS OF POTEI'JTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION AND WILL REQUIRE
FUTURE VERIFICATION
o 1000 2000 FEET
SCALE ~i~~~iiiiiiiiiiii_!
FIGURE 2,7
I ..,
'1'......
n
I
DEVIL CANYON
SLOPE STABILITY MAP
o AREAS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY,
I
1r
ll[
N
III
IlI71
ron
•A A
tJ
o
BEACHING
FLOWS
SLlD~NG (UNFROZEN)
SLIDING (PERMAFROST)
DENOTES AREA EXTENT AND TYPE OF INSTABILITY
PRIMARY BEACl-IING INSTABILITY WITH SOME
POTENTIAL SLIDING
BEACHING AND FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
RIVER MILES
SECTION LOCATiON
AREA OF POTENTIAL PERMAFROST
I.REFER TO FIGURES 22 AND 23 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABILITY MODELS
NO DELINEATION OF PERMAFROST AREA ABOVE EL EVATION
2300 FEET
3.AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION AND WILL REQUIRE
FUTURE VERIFICATION
O~~....;,;IO~OOiiiiiiiiiiiiiiii2~OOO FEETSCALEi:
.NYON
-lTV MAP
FIGURE 2.8
\
\,
j
~;:
••0
',,-,""':,,·=~'~·-·~~~__~.i~~~~_>~"y_._~
......
••,i.
DEVIL CANYON
SLOPE STABILITY MAP
AREAS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY,
1
]I
m
III
III
I (ULI
1-11
xA A
t.t
o
BEACHING
FLOWS
SLIDING (UNFROZEN I
SLIDING (PERMAFROST)
DENOTES AREA EXTENT AND TYPE OF INSTABILITY
PRIMARY BEACHING INSTABILITY WITH SOME
POTENTIAL SLIDING
BEACHING ANO FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
RIVER MILES
SECTION LOCATION
AREA OF POTENTIAL PERMAFROST
I
I
.......
\.REFER TO FIGURES 2.2 AND 23 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABILITY MODELS
NO DELINEATION OF PERMAfROST AREA ABOVE ELEVATION
2300 fEET
l AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION AND WILL REQUIRE
FUTURE VERIFICATION
O,-__I0io;OO;;;;;;;;;;;;;~2~OOO FEET
SCALE e::::::
.NYON
-1TY MAP
FIGURE 2.9
'..'.,
"...'-""'=-~;:~:7-:,,~'.~''."-,-.-~.'-.
,."".'.
.rr
I '
/'t:
I .-.1
'~~.'C:'";?~'I ""
..',11."..;.~';,;
,.lS~o~~V~iA~~L~i$NMAP~r~) _..
'.
,'
;,
....~...'.
.'\'1,1 '"
\It,.~
".
',,1
I .•)
C,JJ AREAS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY:
SECTION LOCAT ION
AREA OF POTE NTIAL PERMAFROST
BEACHING
FLOWS
SLIDING (UNFROZEN)
SLIDING (PERMAFROST)
DENOTES AREA EXTENT AND TYPE OF INSTABILITY
PRIMARY BEACHING INSTABILITY WITH SOME
POTENTIAL SLIDING
BEACHING AND FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
RIVER MILES
I -n
O~~~'O~Oi0ii;;;;iiiiiiiii2iiOOO FEETSCALEC
"A A
t.t
o
I
1I
m
ll1:
III
I tIll)
I REFER TO FIGURES 2,2 AND 2,3 FOR DETAILED
DESCRIPTION OF TYPE OF SLOP€INSTABILITY MODELS
2.NO DELINEATION OF PERMAFROST AREA ABOVE ELEVATION
2300 FEET
3,AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION AND WILL REQUIRE
FUTURE VERIFICATION
I
"."'",
.'-.~'
3,3)
~I
-.',,")1'
;~---------";---/.
"
Q"~."
"',',./"
mf1\.~
ki'
.',',
~i.,\
,~
,'
I
f
J
NYON
JTY MAP
FIGURE 2.10
..".-Q
I ("...<~~./
I
,......(1)0
.,....~r '"~,
r
I
:..,/',
1-"/
:.>,:.
I
\
-
/
/
DEVIL CANYON
SLOPE STABILITY MAP
o AREAS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY:
I
n
m
III
III
I (Ill)
I-n
A A
t.t
BEACHING
FLOWS
SLIDING (UNFROZEN)
SLIDING (PERMAFROST!
DENOTES AREA EXTENT AND TYPE OF INSTABILITY
PRIMARY BEACHING INSTABILITY WITH SOME
POTENTIAL SLIDING
BEACHING AND FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
RIVER MILES
SECTION LOCATION
I.REFER TO FIGURES 2.2 AND 2.3 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABILITY MODELS
NO DELINEATION OF PERMAFROST AREA ABOVE ELEVATION
2300 FEET
3 AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION AND WILL REQUIRE
FUTURE VERIFICATION
-
o 1000 2000 FEET
SCALE ~I~~~~iiiiiiiiiiiiil'
~NYON
L1TY MAP
FIGURE 2.11
~~
_T
if
-
...--.
'.
.....
-
,..(------)
/../
"-..~;
/'
(
(
,/
-_...-or -,
."
'.
"
)
\
"
DEVIL CANYON
SLOPE STABILITY MAP
/
/
/
ED IIREIIS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY:
I.REFER TO FIGURES 2.2 AND 2.3 FOR DETAILEO
DESCRIPTION OF TYPE OF SLOPE INSTABILITY MODELS
2.NO DELINEATION OF PERMAFROST AREA ABOVE ELEVATION
2300 FEET
3.AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION AND WILL REQUIRE
FUTURE VERIFICATION
liTE WIITIINA
'ERLINE
<'./
0....
.I
/
"
./
I
1I
!II
]l[
III
ICIlZ:)
I-lI
)(A A
t.t
BEACHING
FLOWS
SLIDING (UNFROZEN l
SLIDING (PERMAFROST)
DENOTES IIREA EXTENT AND TYPE OF INSTABILITY
PRIMARY BEACHING INSTABILITY WITH SOME
POTENTIAL SLIDING
BEIICHING liND FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
NORMAL MINIMUM OPERATING LEVEL
RIVER MILES
SECTION LOCATION
.'.=.<,."'
y'//
/
O~~~'O~0li;0iiiiiiiiiii2iiOOO FEETSCALEi:
\JYON
ITY MAP
FIGURE 2.12
FIGURE 2.28
WATANA RESERVOIR
INDEX MAP
FIGURE 2.2C
FIGURE 2.19
",.
II
-
FIGURE 2.22
FIGURE 2.26
FIGURE 2.23
FIGURE 2.27
FIGURE 2.25
FIGURE 2.24
DEVIL CANYON RESERVOIR
LOCATION MAP
SCALE:O~~~4__~8 MILESC!
---_---NORMAL MAXIMUM
OPERATING LEVEL
218!1'
-----2300-----CONTOURS ARE IN
FEET ABOVE MSL
--'-
FIGURE 2.20
FIGURE 2.19
2.17
/
.pO /
1>00
FIGURE 2.16
FIGURE 2.15
-
FIGURE 2.14
FIGURE 2.13
"I
:/:~\.._._.,J_;r (
..."'-\.,-...
WATANt
SLOPE STABILI
AREAS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY'
NOTES
I.REFER TO FIGURES 2.2 AND 2.3 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABILITY MODELS
2.NO DELINEATION OF PERMAFROST AREA ABOVE ELEVATION
2300 FEET
3.AREAS OF POTENTIAL PERMAFROST BASED PRINCI PALLY
ON AIR PHOTO INTERPRETATION AND WILL REOUIRE
FUTURE VERIFICATION.
'/
1
II
m
N
III
I (IIO
I -lI
SCALE
BEACHING
FLOWS
SLIDING (UNFROZEN)
SLIOING (PERMAFROST)
DENOTES AREA EXTENT AND TYPE OF INSTABILITY
PRIMARY BEACHING INSTABILITY WITH SOME
I'OTENTIAL SLIDING
BEACHING AND FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
NORMAL MINIMUM OPERATING LEVEL
RIVER MILES
SECTION LOCATION
AREA OF POTENTIAL PERMAFROST
O~"""",,~10~0~O_~20~iOO FEET
WATANA
)PE STABILITY MAP
FIGURE 2.14
II
•.H
.---.
WATANA
SLOPE STABILITY MAP
I-]I
I
]I
m
Xl
III
IIJl[)
TYPES OF SLOPE INSTABILITY'
AREAS OF CURRENT SLOPE INSTABILITY
AREA OF POTENTIAL PERMA FROST
BEACHING
FLOWS
SLIDING (UNFROZEN)
SLIDING (PERMAFROST)
DENOTES AREA EXTENT AND TYPE OF INSTABILI TY
PRIMARY BEACHING INSTABILITY WITH SOME
POTENTIAL SLIDING
BEACHING AND FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
-'---NORMAL MINIMUM OPERATING LEVELA Atj SECTION LOCATION
,1-N
I.REFER TO FIGURES 2.2 AND 2.3 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABILITY MODELS
2.NO DELINEATION OF PERMAFROST AREA ABOVE ELEVATION
2300 FEET
3.AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION AND WILL REOUIRE
FUTURE VERIFICATION
SCALE 0~1IIIIIIIII~IOO~Oiiiiii~2~0!.OO FEET
IA
OlTY MAP
FIGURE 2.15
'.
I,-(0 '.
....-•......~...:'~..:;'.
....-1WATANA
SLOPE STABILITY MAP
~.
~"
::
o AREAS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY:
I
l[
1lI
I!l
III
I (]J[}
I-]1
xA A
tt
Oi
BEACHING
FLOWS
SLIDING (UNFROZEN)
SLiOING (PERMAFROST)
DENOTES AREA EXTENT AND TYPE OF INSTABILITY
PRIMARY BEACHING INSTABiliTY WITH SOME
POTENTIAL SLIDING
BEACHING AND FLOWS POSSIBLE IN OEFINED AREA
NOR MAL MAXIMUM OPERATING LEVEL
NORMAL MINIMUM OPERATING lEVEl
RIVER MILES
SECTION LOCATION
AREA OF POTENTIAL PERMAFROST
REFER TO FIGURES 2.2 AND 2.3 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABILITY MODELS
2.NO DELINEATION OF PERMAFROST AREA ABOVE ELEVATION
2300 FEET
3.AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION AND WILL REOUIRE
FUTURE VERIFICATION
/
-/
._----"':'.........
","--:::"'~--.....
..---=0
FIGURE 2,16
0~~~~IOOO~_~2~O:X>FEETSCALEI:,
i
1-N:(lL:DIl
{,
~"
!*-0"--.-.~.".-..';.~~,•H'_ •••
""'".",
......
"-J
[
/
/
r'---.--'
/
\"-
"'.....
I.(-~. !--..--''\
,.
I
__r
,-~,-.-......':.,<::~::'1[
\J-,I
m-li
S OP
AT.N
A81 T,AP
8 ~.
.~:1:-'-.>
I.
".'
..•../
ij"f.
,/
.f ,'.'/
...\u......",
u
I
WATANA
SLOPE STABILITY MAP
...
o AREAS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY:
I
II
III
Il[
III
.l(ll[}
I -II
y.
A A
tl
o
BEACHING
FLOWS
SLIDING (UNFROZEN I
SLIDING (PERMAFROST I
DENOTES AREA EXTENT AND TYPE OF INSTABILITY
PRIMARY BEACHING INSTABILITY WITH SOME
POTENTIAL SLIDING
BEACHtNG AND FLOWS POSSIBLE IN DEFINED ARE A
NORMAL MAXIMUM OPERATING LEVEL
NORMAL MINIMUM OPERATING LEVEL
RIVER MILES
SECTION LOCATION
AREA OF POTENTIAL PERMAFROST
NOTES
REFER TO FIGURES 2.2 AND 2.3 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABILITY MODELS
2.NO DELINEATION OF PERMAFROST AREA A80VE ELEVATION
2300 FEET
3.AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION ANO WILL REQUIRE
FUTURE VERIFICATION
o 1000 2000 FEET
SCALE i~~~~iiii;iii=aiiiiii;iij
N
-._.~
1~2
.~,,
II
....'--:-;.:..
--z---------------J',~
II
I
'y MAP
;.••.J
.,,"
FIGURE 2.18
·,'.00('
!lot ••,.•'.'"•
lu'~'f'll.',j'I,.I ..)
-
I '
t
I-II (TIl)
WATANA
SLOPE STABILITY MAP
D AREAS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY:
I
]I
]I[
N
III
liN)
I-]I
A A
t.t
BEACHING
FLOWS
SLIDING (UNFROZEN)
SLIDING (PERMAFROST)
DENOTES AREA EXTENT AND TYPE OF INSTABILITY
PRIMARY BEACHING INSTABILITY WITH SOME
POTENTIAL SLIDING
BEACHING AND FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM DPERATING LEVEL
NORMAL MINIMUM OPERATING LEVEL
RIVER MILES
SECTION LOCATION
-
I.REFER TO FIGURES 2.2 AND 2.3 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABILITY MODELS
2.NO DELINEATION OF PERMAFROST AREA ABOVE ELEVATION
2300 FEET
3.AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION AND WILL REOUIRE
FUTURE VERIFICATION
0~~~IO~O~0:i;;;;;iiiiii2~Oiii?O FEETSCALEl:,
MAP
FIGURE 2.19
-
.,
I
WATANA
SLOPE STABILITY MAP I'_:
.'0 .,(.~.-.~In
I -lI
BEACHING
FLOWS
SLIDING (UNFROZ EN)
SLIDING {PERMAFROST}
DENOTES AREA EXTENT AND TYPE OF INSTABIliTY
PRIMARY BEACHING INSTABIliTY WITH SOME
POTENTIAL SLIDING
BEACHING AND FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
--_.-NORMAL MINIMUM OPERATING LEVEL
RIVER MILES
I
II
III
:Ill
III
I(lll:)
o AREAS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY'
.~...
--~
A Atl'SECTION LOCATION
o AREA OF POTENTIAL PERMAFROST
'y
~';:"
,,
/...../
.,
"/"
I REFER TO FIGURES 2.2 AND 2.3 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABIliTY MODELS
2.NO DELINEATION OF PERMAFROST AREA ABOVE ELEVATION
2300 FEET
3.AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION AND WILL REQUIRE
FUTURE VERIFICA1,ON
FIGURE 2.20
WATANA
SLOPE STABILITY MAP
I -JI
I
]I
m
:Ill
III
I (:Ill I
Ie,
['"j AREAS OF CURRENT SLOPE INSTABIU TY
TYPES OF SLOPE INSTABILITY;
BEACHING
FLOWS
SLIDING I UNFROZEN)
SLIDING (PERMAFROST)
DENOTES AREA EXTENT AND TYPE OF INSTABILITY
PRIMARY BEACHING INSTABILITY WITH SOME
POTENTIAL SLIDING
BEACHING AND FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
-----NORMAL MINIMUM OPERATING LEVEL
X RIVER MILES
A Ati SECTION LOCATION
U AREA OF POTENTIAL PERMAFROST
NOTES
I.REFER TO FIGURES 22 AND 2.3 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABILITY MODELS
2.NO DELINEATION OF PERMAFROST AREA ABOVE ELEVATION
2300 FEET
3.AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION AND WILL REOUIRE
FUTURE VERIFICATION
-0~~~'0~0ii;i0i;;;;;iiiiii2~O?0 FEETSCALEi:,
JA
_ITY MAP
FIGURE 2.2\
I
I
•411"..
/
II R
.......""'•.....
I I
''1 '~-,'
-::...'~j ,,_..-
\
P...?'."
-"
Eii:....!.L.~..·.itZ8I
~
WATANA
SLOPE STABILITY MAP
LEGEND
r;;1 AREAS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY:
I.REFER TO FIGURES 22 AND 2.3 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABILITY MODELS
2.NO DELINEATION OF PERMAFROST AREA ABOVE ELEvAnON
2300 FEET
3.AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION AND WILL REQUIRE
FUTURE VERIFICATION
I (TIl)
1
II
m
llz:
III
l(N)
l-ll
xA A
tot
o
BEACHING
FLOWS
SLIDING (UNFROZEN>
SLIDING (PERMAFROST)
DENOTES AREA EXTENT AND TYPE OF INSTABILITY
PRIMARY BEACHING INSTABILITY WITH SOME
POTENTIAL SLIDING
BEACHING AND FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
NORMAL MINIMUM OPERATING LEVEL
RIVER MILES
SECTION LOCATION
AREA OF POTENTIAL PERMAFROST
- I O..._I0'iOO~iiiiiiiiii;2~OOO FEETSCALEI~.-
\lA
LITY MAP
FIGURE 2.22
......*:',}"....
k'u 'I AREAS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY:
\
I
II
m
:r;r
III
I(N)
I -lI
A A
t.t
Cl
BEACHING
FLOWS
SLIDING (UNFROZEN)
SLIDING (PERMAFROST I
DENOTES AREA EXTENT AND TYPE OF INSTABILITY
PRIMARY BEACHING INSTABILITY WITH SOME
POTENT IAL SLIDING
BEACHING AND FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
NORMAL MINIMUM OPERATING LEVEL
RIVER MILES
SECTION LOCATION
AREA OF POTENTIAL PERMAFROST
REFER TO FIGURES Z 2 AND 2 3 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABILITY MODELS
Z,NO OELINEATION OF PERMAFROST AREA ABOVE ELEVATION
2300 FEET
3,AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PMOTO INTERPRETATION AND WILL REQUIRE
FUTURE VERIFICATION
O~~~IO~0i;i0iiiiiiiiiiiiZiiiI~OO FEETSCALE'_,
FIGURE 2.23
1,------
WATANA
SLOPE STABIL ITY MAP
PERMAFROSTOFPOTENTIALAREA
SECTION LOCATION
I -Il:
ES
DETAILEDNOTAND2.3 FOR ILiTY MODELS
REFER TO FIGURES P:~F SLOPE INS TAB ELEVA nON
I DESCRIPTION OF TY ARE A ABOVE
TION OF PERMAFROST
2.NO DELINEA 0 PRINCIPALLY
2300 FEET NTIAL PERMAFRO~TD 8:L~REQUIRE3.AREAS OF PO~TERPRETATION A
ON AIR PHV~~FICATIONFUTURE
A A
t.t
D
+-,
"
-
--------------------:----------------LEGEND E INSTABILITY
NT SLOPAREASOFCURREi:,:~~]PE INSTABILITY:TYPES OF SLO
BEACHING
I FLOWS FROZEN)~SLIDING (UN RMAFROST)YPE OF INSTABILITY
Ill:SLIDING (:~EA EXTENT AND \WIT H SOME
II DENOTES ACHING INSTABILIT EA~(llZ:)~~~~~iA~ESLIDING POSSIBLE IN DEFINED AR
BEACHING AND FLOW~PERATING LEVEL
NORMAL MAXIMU:OPERATING LEVEL----NORMAL MINIMU
RIVER MILES
JA
ITY MAP
SCALE
o 2000 FEETIOQQ••.:=?
FIGURE 2.24
,/,
WATANA
SLOPE STABILITY MAP
I-lI:
I
n
II[
Ilr
III
ICIll:1
AREAS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY'
BEACHING
FLOWS
SLiOING (UNFROZEN)
SLIDING (PERMAFROST)
DENOT ES AREA EXTENT AND TYPE OF INSTABILITY
PRIMARY BEACHING INSTABILITY WITH SOME
POTENTIAL SLIOING
BEACHING AND FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
-----NORMAL MINIMUM OPERATING LEVEL
)(RIVER MILESA Atl'SECTION LOCATION
,--------::----.J AREA OF POTENTIAL PERMAFROST
I.REFER TO FIGURES 22 AND 2.3 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABILITY MODELS
2.NO DELINEATION OF PERMAFROST AREA ABOVE ELEVATION
2300 FEET
3.AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION AND WILL REQUIRE
FUTURE VERIFICATION
IA
.1TY MAP
SCALE O~~~'O~0;ii0iiiiii~2~OO.0 FEET
FIGURE 2.25
I (N)
I
I
-
]I
'\
~.
I
WATANA
SLOPE STABILITY MAP
I-II
I
II
1II
]l[
III
I(]l[)
''''',~,
D AREAS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY:
BEACHING
FLOWS
SLIDING (UNFROZEN)
SLIDING (PERMAFROST)
DENOTES AREA EXTENT AND TYPE OF INSTABILITY
PRIMARY BEACHING INSTABILITY WITH SOME
POTENTIAL SLIDING
BEACHING AND FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
-----NORMAL MINIMUM OPERATING LEVEL
•RIVER MILES
A At1 SECTION LOCATION
I.REFER TO FIGURES 2,2 AND 2.3 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABILITY MODELS
2.NO DELINEATION OF PERMAFROST AREA ABOVE ELEVATION
2300 FEET
3,AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION AND WILL REQUIRE
FUTURE VERIFICATION
-
C\J,'.~,.
...",'.'..~,/,
. ..".....
.:;':'~
-
0,__I0o;O;;;0;;;;;;;;;;;;;20~PO'FEET
SCALE ;.,
NA
ILiTY MAP
FIGURE 2.26
,K
·1~·
'}
I
-
,-.....-.~.
WATAf'JA
SLOPE STABILITY MAP
I-ll
I
1I
m
ll[
III
I (ll[)
A At.l SECTION LOCATION
BEACHING
FLOWS
SLIDING (UNFROZEN)
SLIDING (PERMAFROST)
DENOTES AREA EXTENT AND TYPE OF INSTABILITY
PRIMARY BEACHING INSTABILITY WITH SOME
POTENTIAL SLIDING
BEACHING AND FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
-----NORMAL MINIMUM OPERATING LEVEL
RIVER MILES
I.REFER TO FIGURES 2.2 AND 2.3 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABILIl)'MODELS
2.NO DELINEATION OF PERMAFROST AREA ABOVE ELEVATION
2300 FEET
3.AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION AND WILL REQUIRE
FUTURE VERIFICATION
!::;;,d AREAS OF CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY:
I (N)
-
o 1000 2000 FEET
SCALE iIIIIc:::......~~~!
~A
L1TY MAP
FIGURE 2,27
I
t
]l-II
N-II~
SLOPE
WATANA
STABILITY
ill-I
I
MAP \.'.•-y,
\'.,y.I "',~'<......:\".
I
/.
(;".
/-,
it ..;,/';
o AREAS Of CURRENT SLOPE INSTABILITY
TYPES OF SLOPE INSTABILITY'
REFER TO FIGURES 2.2 AND 2.3 FOR DETAILED
DESCRIPTION OF TYPE OF SLOPE INSTABILITY MODELS
2.NO OELINEATION OF PERMAFROST AREA ABOVE ELEVATION
2300 FEET
3.AREAS OF POTENTIAL PERMAFROST BASED PRINCIPALLY
ON AIR PHOTO INTERPRETATION ANO WILL REQUIRE
FUTURE VERIFICATION.
I (I[)
II
I
n
ill
rr
III
I(rrl
I -I!
SCALE
BEACH IN
fLOWS
SLIDING (UNfROZEN)
SLIDING (PERMAfROST)
DENOTES AREA EXTENT AND TYPE Of INSTABILITY
PRIMARY BEACHING INSTABILITY WITH SOME
POTENTIAL SLIDING
BEACHING ANO FLOWS POSSIBLE IN DEFINED AREA
NORMAL MAXIMUM OPERATING LEVEL
NORMAL MINIMUM OPERATING LEVEL
RIVER MILES
SECTION LOCATION
AREA OF POTENTIAL PERMAFROST
0~11IIIIIIII1IIIIIIII~IO~OO~;;;;;;;2;;l0F FEET
FIGURE 2.28
~··~~·1
2000
"-~1 1 ~~l 1 1
~1500
I.LJ
I.LJu..
~
z
0
~
~
I.LJ
..J 1000w
500
...---TILL
RESERVOIR LEVEL ~
BEDROCK
\&'"~.~RIVER
ASSUMPTION:THIN UNFROZEN VENEER
OF·SANDY TILL
NOTE:SEE FIGURE 2.6 FOR
SECTION LOCATION
o 500 1000 FEET
SCALE i !
SECTION A-A
DEVIL CANYON RESERVOIR
POTENTIAL MINOR BEACHING
FIGURE 3.1 liU
2000
i='
I.LI
I.LI
LL.-
Z
0 1500r-et>
W
...J
W
1000
~.RESERV~LEVEL ••~~~,7"..~COLLUVIUM a
-~RIVER
BEDROCK
1
ASSUMPTIONS:COLLUVIUM.UNFROZEN BEDROCK PROBABLY IN
CONTACT WITH THE RESERVOIR LEVEL
NOTE:SEE FIGURE 2.7 FOR
SECTION LOCATION
o 500 1000 FEET
SCALE i !
SECTION B-B
DEVIL CANYON RESERVOIR
POTENTIAL MINOR BEACHING
FIGURE 3.2 m
"-----1 c---~~-l "-1 C~~--l ~--~I 1 -)
2500
"n NG£.~\~p..R?.~.,'~s __.-.I \)•.\0.I!II'_.-"""_·.#J~C·~,~~.,..
.,--•.p •.•.Q'••,:_"POSSIBLE TOE EROSION .'.'...,•.s;:f:.
_•.4._p:·:~~·:::.··~.~·.:·.~"."....,.•.,~.~.~~P~Wi.:-,..:.,.
..•._,.~~......~::c;..
.....~~-:...,...~.>E.:~~.!':.::.0'·0"~POTENTIAL FAILURE SURFACE..._.s
2000
I-
UJ
It-rz1500 RESERVOIR LEVEL0
I-~~~.--'UJ
•·······-:IVER
.....J
UJ
1000
ASSUMPTIONS:BASAL TILL,FROZEN
500
NOTE:SEE FIGURE 2.10 FOR
SECTION LOCATION
O.500 1000 FEET
SCALE i !
SECTION C-C
DEVIL CANYON RESERVOI~
POTENTIAL LARGE SLIDE
\
II FIGURE 3.3 m
,_..]~··--·l •...-..~)
2500
i='w
LLI
~
Z
0~2000
~
W
...J
IJJ
1500
RESERVOIR LEVEL (HIGH)~
T'":~.', .~'q~'°t'~.o.7
RESERVOIR LEVEL (LOW)...,...•...;.;:...,.~.,"'"&:1l;T'::~'~:\§M~~....'.~~...•~Ia~(-
,••••: • • ",0 ,\TIL L"'ar'Wi .
BEDROCKJ
ASSUMPTIONS:BASAL TILL,THIN VENEER OF
LACUSTRINE MATERIAL FROZEN
IN PLACES.
NOTE:SEE FIGURE 2.16 FOR
SECTION LOCATION
o 500 1000 FEET
SCALE i !
SECTION D-D
WATANA RESERVOIR
POTENTIAL BEACHING
FIGURE 4.1 m
<~~~l '~~~'~"-~~-l -~'~~--.~.~-~l
2500
~
IJJ
IJJ
~
zQ 2000
~>
IJJ
-'IJJ
1500
LACUSTR;kNE
-----
RESERVOIR LEVEL (HIGH)&=================_-~=~=~
,.•a .I ••:-r-~o·.:,.::··:-,~":-.~::..~.;.:'.:~'.~{].:~:.:<:.'0'
RESERVOIR LEVEL (LOW)~~''''''-:Q'.":'•.·.1 :-,.1 '•,,,0 •..···.4··.·Il>I....'0 .••••',".•••-•.~..·-:.·.-.·'t·'€1\t;I'.......'r,'"'if'".'"...: ·.•,.0:;...0·::..7"•,[• ••...,.....'0
"rWATANA CREEK J'AIL'-·0 ...I
"_BEDROCK TILL
<J
ASSUMPTIONS:STRATIGRAPHY CONSISTS OF GLACIO -LACUSTRIN E
SANDS AND SILTS,TILL.TILL IS FROZEN J
LACUSTRI NE MAY BE PARTLY FROZEN.
NOTE:SEE FIGURE 2.17 FOR
SECTION LOCATION a sao 1000 FEET
SCALE i !
SECTION E-E
WATANA RESERVOIR
AREA OF POTENTIAL FLOWS
FIGURE 4.2 m
1 ~1 '~'~~~-~l ~'~~-1 )
LACUSTRINE
PLAIN TERRACE
RESERVOIR7"LEVEL (HIGH)
RESERVOIR
~~:.:?,-::",.~.~,......-...--...~---:;.=~_'o'•••~._c o •.~.~,··'e'···Q «.~,....~~....,"fr"0;•.,•..•••.,~r -"",I~
-...~.;.>.~~:''.,"':;'~'."""-. .'
,.'a":'*.~.::y'?~\""l-'-......~.:::"y.BEDROCK
~1'~,,'.'~.~~t>...'\../."•.;.'.~yl"/\'TIL L
2500
2000
1500
ASSUMPTIONS:BASAL TILL,PRIMARILY FROZEN
NOTE:SEE FIGURE 2.21 FOR
SECTION LOCATION
a 500 1000 FEET
SCALE i !
SECTION F-F
WATANA RESERVOIR
POTENTIAL ROTATIONAL SLIDES AND FLOWS
FIGURE 4.3 m
-,~--~l "']~·-·~1 ~...-•..."]
2500
-I-
l1J
l1Ju..---
z
Q 2000
~>
UJ
...J
w
1500
~-I'RESERVOIR LEVEL (HIGH)",~-':,~~':~~::~7\~>:~·:,)~·:~:·~.~.·j'~·~;·,,:POTENTIAL
.•'_"'...~:o"-,.:..."0~.)',t~.~,;-:\~.;:~\<::,~:~>.:_~1:,~~:\.~·~'T.~~~{/~.:~~,,~:,:'..:~~'~~}FOR FLOWS
RESERVOIR LEVEL (LOW)_,',:'0..';:",'-:~':",.0.::;',::'u~·.~:','.~",,:~.:.:~.:,:.:":."i~'·:,:?',~',<:\'.":~:.0'.:.-::.',~::~.:0::':;
ASSUMPTIONS:SANDY MATERIAL,FROZEN
NOTE:SEE FIGURE 2.26 FOR
SECTION LOCATION
500 1000 FEET0
!SCALE i
SECTION G-G
•
WATANA RESERVOIR
A"'OF FLOW FAILURES
4.4
ARE
FIGURE