HomeMy WebLinkAboutAPA Board of Directors Meeting May 3 1985OLD BUSINESS
ALASU POWll AOTBOI.In
BOil.D OF D li.!CTORS Hl!TISG
Juneau Borough Chamber•
Friday, May 3, 1985
8:30a.m.
I. A. Action Items
5. Liceasing Review and Consideration of Proposed Sta~in g of
Construction of the Susitna Hydroelectric Project
SUPPLEMENTAL INFORMATION
Supplement -ENGINEERING
Supplement 2 -PROJECT COSTS & ECONOMICS
Supplement 3 -POWER & ENERGY PRODUCTION
Sup~lement 4 -FINANCLAL ANALYSIS
Supplement 5 -ENVIRONMENTAL ANALYSIS
STAGED COr~STRUCTIOH OF THE SUSITNA HYDROELECTRIC PROJECT.
A. Action Item
Approval tu incorporate stag!d construction of the Watan1 facilities into
the Susitna Hydroelectric Project, and to update and/or optimize other
features, as appropriate. See Figure 1, Plan and Schedule.
B. Background
The Application for License before the Federal Energy Rt9ulatory Commiss-
ion (FERC), submitted February 1983, proposes a two-stage project on the
Sus1tna River. The first stage would be 1 facility at the Watana site
with the dam built to an elevation of 2,205 feet, 1 second facility at
the Devil canyon site would have a dam built to an elevation of 1,465
feet. Several planning studies determined that this arrangement opti~i
zes the power development of the Sus1tna River.
At the February 1985 Board ~neeting, Staff repornd on a preliminary
analysis of staged construction of the Watana facility which. indicated
that the Project, as presented in the FERC License Application, is still
the opt1trum plan, however, the staged construction would (1) result in
lesser 1n1tia1 cost (and thereby mf9ht facilitate financing}, (2) require
a smaller State contribution, and (3) provide additional decision points
in the project plan and schedule that would allow project development to
be more closely aligned with actual system growth. The benefits of
staging would be at the expense of a scmewhat higher eventua 1 tota 1
project cost.
Staff recommend~. and the Board authoriz!d, further studies be completed
to confirm the preli~inary assessments of the staged project in the areas
of engineering, econOCDics, finance, and environment. This Action Item
reports on those studies.
C. Issues
1. Engineering. The stag!d project would be constructed in three
stages instead of the currently proposed two stages. The stages
would be:
Stage I -Wauna Initial Dam -Dam Crest Elevation 2025
Stage II -Devil Canyon Dam -Dam Crest Elevation 1465
Stage III -Watana High Dam -Da~ Crest Elevation 2205
Supplement 1 descri~es the engineer ~ng aspects of construction
staging. and contains the report of the Engi~eering External Review
Panel on Staging.•
2. Project Cost and Economics. Staging the Watana development would
reduce 1n1tial construction costs and the re<~uired state contribu-
tion for rate stabilization. However, total construction costs of
9217/307
the three-stage development wi 11 be higher than those of the two-
stage development, and bonding requirements will be greater.
Staging the Watana Oam reduces the benefit/cost ratio of the License
Application scheme by a modest degree as reported in February.
Supplement 2 provides estimated construction cost in both real and
nominal dollars and provides an economic comparison between the
two-stage and three-stage projects.*
3. Power and Energy. The three-stage project would provide the oppor-
tunity to align project capacity ·and energy more closely with actual
regional demand growth as it occurs in the future. There would be
increased flexibility in timing the Susitna project increments to
match the utility needs.
Supplement 3 describes energy and capacity data for the staged
project, and provides a -comparison between the two-stage and three-
stage projects.*
4. Finance. The amount of bonds required to fund the construction of
the first two stages of the three-stage project is 1 ess than that
required under the FERC concept. However, due to inflation and some
real cost differences, the bonds required to construct all three
stages is greater than that required under the FERC concept.
Due to the relatively greater usability and lower initial costs, the
three-stage project reduces the amount required for the utilities to
be fully rate stabilized.
Supplement 4 provides an analysis of financing alternatives for the
two and three stage project, the cash flow requirements, and an
analysis of state contributions.*
5. Environment. The aquatic impacts of the Stage III of the project
(Watana High Dam and Devil Canyon Dam) would remain essentially the
same as the currently proposed project. The intermediate stages,
Stage I (Watana Initial Dam) and Stage II (Watana Initial Dam and
Devil Canyon Dam) would have different downstream effects because of
less capability to reregulate the annual river flows, and
consequently, a somewhat different thennal r!9ime for the Watana
reservoir. During the early years of the ProjP.ct this cooler
thermal regime results in an increased ice cover downstream from the
dams as compared to the full developme·t, with a resultant increase
in overtopping fl~ of cooler water into aquatic habitat in the
side sloughs of the middle river. This may have a negative impact
on the survival of incubating salmon in these sloughs. However, it
is possible to mitigate for this impact by placing berms and dikes
so as to completely protect the slough from overtopping flows.
A decision to pursue three stage developrr~nt of the Susitna
Hydroelectric Project would generally have no major adverse impacts
or. any w11dlife or botanical resources within the project area.
From 1 wildlife or botanical resource viewpoint, three stage
development would 1n fact have several advantages over the current
license application project. Under this plan approximately 15,000
acres of w11dlife habitat, which would be inundated by the High
Watana impoundment, would not be inundated for roughly 10 years.
Construction acttvities would continue over a longer period of time,
and thus disrupt wildlife for 1 longer period. However, the level
of disturbance to wildlife during Stage III construction would be
1 ess due to the reduced magnitude of the construction effort, the
presence of an existing infrastructure developed during Stages I and
II, and the extension of the time period during which public ~ccess
would be prohibited. Since Devil Canyon pool would inundate one of
the principal borrow areas for fill material for the Watana Damsite,
it would be necessary ta ·open additional borrow areas when Watana
Dam is raised in Stage III.
The primary eff ect of staged construction on cultural resources are
twofold. First, 1t would reduce the nunter of archeogical sites
initially impacted by reservoir f1ooding. Second, i t would allow
more time for studying those sites and for implementing the cultural
resources mitigation plan. While t~e total construct ion workhouM
would be less and the construction period would be less, and the
construction period would be reduced by one year for Stage I as
compared to High Watana, the total nunter of workeM required at
peak construction would be similar. Workforce requirements for
Stage II (Devil Canyon) would not change. A workforc e {which waul~
be smaller than for Stage I) would be required to ct onstruct Stage
III. Therefore, the general size and timing of socioeconomic
effects are not anticipated to differ substantially for Stages I and
II than for the License Application. Adding Stage III would result
in continued but smaller project-related employment opportunities
and attendant socioeconomic effects.
Supplement 5 provides an assessment of the environmental effects of
the staged project and a comparison with the currently proposed
project.*
6. Licensing. The staged project will require additional environmental
evaluation by FERC staff to pennit preparation of a Final
Environmental Impact Statement (FEIS). This additional period of
evaluation could delay the completion of the FEIS, resulting i n a
corresponding delay in the current hearing schedule. FE~C has asked
to be promptly apprised of Board action so that appropriate resource
planning can take place.
D. Costs of Revising License Application
9217/307
A decision to proceed with revising the application is anticipated to
increase the Power Authority project licensing costs by approximately
$972 ,000 not 1 nc 1 udi ng 1 ega 1 fees. Tab 1 e 1 shows the source of the
additional costs.
Table 1. Estimated Additional Consultant Costs for Licensing
to Cover Project Staging
Engineering
Environment
Geotechnical
Licensing and Permitting
Logistics
Need for PO'fier
Transmission
Hydrology
External Review Panel
Management and Adminis~ration
Total
Grand Total
FY85
$94,000
56,000
20,000
as ,ooo
56,000
54,000
30,000
395,000
FY86
$298,000
149,000
20,000
59,000
46,000
5,000
577,000
$972,000
E. Project Schedule
Considering only the licensing delays accurru1ated to date, the project
full power on-line date has slipped from 1993 to 1997; this latter date
can be changed to 1996 with staging. Table 2 shews on-line dates for the
current and staged projects.
Table 2. Online Oates for the Current and Staged Projects
Assuming Ffnal Design Authorization in December 1985
Cun-ent Project Staged Project
Watana Initial Dam
Fi~t Unit Power
Full Power
H/A Oct. 1995
Dec. 1996
Devil Canyon Dam
First Unit Power
Full Power
2002
2002
2002
2002
Watana High Dam
Oct. 1996
Dec. 1997
2008
2008
9217/307
First Unit Power
Full Power
The shorter construction time f.)"" \latana Initial Dam results in a one
year reduction for the on-line date of the first stage. In addition,
there is increased opportunity t o adjust on-line dates of the several
stages to more closely match project eneqy and capacity with system
demands .
The on-line dates suggested here reflect the initiation of design a,.,d
geotechnical programs in December 1985. The design and geotechnical
programs are critical path activities and projected on-line dates are as
sensitive to delays in initiating these programs as they aN! to the
licensing date.
F. Staff Findings.
l. Staged construction is practical from an engineering point of view.
2. Although the Project, as presently incorporated in the Licensing
process, has the optirrum dam height from an economic perspective,
staged construction would provide several benefits:
A) Staged construction would lawer initial development costs, but
would increase real project costs about 9~.
B) Staged construction would align project ener'9)' and capacity
more closely with actual system demands, and would provide
greater flexibility in responding to future rates of system
growth.
C) Staged construction would lower the required state investment
in the project and could facilitate financing of the project.
D) The environmental impacts of the staged project are only
modestly greater than the current project and are within
acceptable bounds with mitigation.
G. Options
9217J1n7
1. Approve:
A) Incorporation of staged construction of the Watana facilities
as part of the proposed project; and
B) Co~letion by stafi of required studies and preparation of
materials necessary for their submission to FERC, including
those rev1 s ions to the phys 1 ca 1 arrangement of the project
other than staging, which are considered to be desireable means
of reducing the project cost; and
C) Staff enlisting advice from counsel for procedural action~ with
FERC to the extent necessary to assure orderly and expeditious
pursuit of the EIS process and, ultimately, the FERC license;
and
0) Staff approaching FERC with counsel to submit necessary
documentation to allay FERC's concerns with budget and
schedule, and to detennine FERC License schedule implications
2.
of staging. These implications will be corrrnunicated to the
Board as soon as they are determined; and
E) Taking funds for the License revision from the Sl .2 mil 1 ion
Board Contingency Fund.
A) Disapprove incorporation of staged constn.~ction of the Watana
facilities and thereby confinn the Board's corrmitment to the
currently proposed project, and
B) Authorize staff to prepare materials necessary for updating the
Application for License to reflect realistic on-line date.
H. Recommendations
Option 1.
9217/107
ALASU PO\l!R AUTBORilT
SUSITNA BYDRO!L!CTRIC PROJ!CT
STAGED CONSTR UC TION
!HGIN!ERING
I. Staged Construction Concept
Supplement 1
The Application for License before the Federal Energy Regulatory Commis-
sion (FERC), submitted February 1983, proposes a tvo-stage project on the
Susitna River. The first stage would be a facility at the Watana Site
with the dam built to an elevation of 2205 feet (see Figure 1-1), and a
second facility at the Devil Canyon site, with the dam built to an eleva-
tion of 1463 feet (see Figure 1-2). Planning studies i ndicate that this
arrangement optimizes the power devel o pment of the Susitna River.
While the propo sed dam height provides the most cost effective approach to
achieving the optimum power development of the river, it requires a large
initial investment in the Watana stage of the project and would result in
a period during vbich it ia anticipated there would be some e.xcess capa-
city.
A three-stage project could be initiated by the construction of Watana Dam
to a crest elevation of 202.5 feet (see Figure 1-3). With its crest at
elevation 202.5, the dam would require substantially leu material, con-
• true tion time would be reduced and only four of the planned six uni ta
would be installed. Development of the transmission system would also be
staged to match trani!Disaioo capacity with generating capacity (see Figure
1-4). These changes would allow Stage I of the project to be brought on
K3820.10
850426
line at a lover coet, although vitb reduced capacity and energy. After
completion of Stage I, Stage II, consisting of Devil Canyon Dam, vould be
constructed. The Devil Canyon facility i1 identical vith that in the FERC
Application for Licente.
~en load growth indicates the need, Stage III, Watana High Dam, vould be
constructed by raising the Watana Initial Dam to the full height des-
cribed in the FERC Application for License (see Figure 1-5).
II. External Review Panel of Consultants
The staged construction concept was presented in detail to the External
Review Panel of Consultants on 15 April 1985. Their report (copy
attsched) confirms the feasibility of the staging concept. The report
also raises the issue of the surface powerhouse in place of the under-
ground facility included 1n the FERC Application for License.
The possibility of a surface po werhouse was evaluated in the summer of
1983. It was decided at that time not to attempt this change to the
FERC Applciation for License in view of the potential for delay in the
licensing process.
Inasmuch as staging will involve a significant change in the FERC License
process, it is believed appropriate now to study the coat effects of a
surface powerhouse and, if warranted, include such a change to the FERC
Application for License along with staging.
III. Description of Facilities -Staged Concept
Watana -Stage I
The Watana Initial Dam would be built to elevation 2025 vith a maximum
normal reservoir elevation of 2000 (see Figure 1-5). The internal zoning
M3820.11
850429 2
of the earthfill dam would incline the impervioue core. The inclination
of the core would reduce the amount of shell material required for
atabi 1 i ty of the Stage II! dam that would be 1ubmerged by the S r.~ge I
pool, and therefore placed during Stage I construction. When the dam i1
being raised, all the additional fill could then be placed in the dry
during the seasonal dravdovn of the reservoir. The raiaing of Watana
Da:n involves no adverse effects oa the safety of either the Stage I or
Stage III dam, and no unusual construction operation i1 required during
raising. Ao additioaal five feet of freeboard ia added in Stage I to
facilitate flood control with the SmAller reservoir storage volume.
The spillway and approach channel excavations would be deepened by
approximately 185 feet bel o w that shovo in the F!RC license concept 1n
order to accommod ate the reservoir during Stage I (see Figure 1-6). The
rock excavated fr o m these ar e as woul d be used in the construction of the
dam 11.nd wo uld minimize or eliminate the need for opening a quarry site
during Stage I. The deeper excavation would be designed with suitable
rock reinforcement and berms. The spillway in either concept would pass
the potential maximum flood.
For Stage I, there would be one outlet facility structure and two po wer
intake structures (see Figure 1-3). The invert elevations would accoa~
modate the lover reservoir elevations. The outlet facility in conjunc-
tion with the four powerhouse units in Stage I 1o1ould be designed to dis-
charge a 50-year flood before flow would be discharged over the spillway.
The same applies to the current two-staged project.
The powe rbouse ia Stage I would have four units. With the lower head
available in Stage I, each unit would generate 130 MW for a total of 520
MW.
M3820.12
The conetructioo echedule for Stage I hat been 1hortened by one year ever
that vbich wae planned for in the F!RC licen•e concept. The shortening
of the schedule ie a result of a decrease in the q~ntitiee of the fill
material neceeaary for the Stage I conetr~ction.
Devil Canyon -Stage JI
Devil Canyon has aot changed from the F!RC licenee concept.
Watana -Stage Ill
The Watana Initial Dam would be raised to elevation 2205 with a maximum
nol"lll41 reservo1r elevation of 2185 (see Figure 5). During seasonal
drawdovn when the Stage I reservo1r elevation is belov elevation 1945
(the elevation of the upstream benn ) rockfill ~ould be in the dry on the
upstream side of the dam. The material for the rockfill would be exca-
vated from quarry A and the ~terial for the core and filters fr o m borC"oll
a•eaa D, !, and F.
The c~ncrete spillway ogee crest would be raised to !1. 2135 (see Figure
7).
The outlet facility structure and the tvo power intakes would be raised
to elevation 2201. A third power intake would be built in Stage III with
an invert elevation at 2012.
Two additional units would be added to the Powerhouse bringing the total
number of units to six. After completion of Stage III, the capacity of
the Powerhouse would increase from 520 M\i to 1020 KW because. of the
increase in head on the four Stage I unite and the addition of two more
units at 170 MW each.
M3820 .13
850425 4
LIST OF FIGURES
Figure 1-1 FERC License Plan Layout for Watana
Figure 1-2 F!RC Licenee Pian Layout for Devil Canyon
Figure 1-3 Watana Plan Layout -Staged Construction
Figure 1-4 Staged Construction Tranamission Line
Figure 1-5 Watana Dam Embankment Cross Sections -Initial and Bigh Dam
Figure 1-6 Watana Dam Spillway Cross Sections -FERC License Concept and
Initial Dam
Figure 1-7 Watana Dam Spillway Cross Sections -Initial and High Dam
M3820/13A
850426 5
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j
2/12/86
WA T ANA DAM GENERAL PLAN
FERC LICENSE CONCEPT
RESERVOIR
El.2186
SC LE
0 600Ft.
0 c
:D
m -• ...
/
DEVIL CANYON GENERAL PLAN
FERC LICENSE OR STAGED CONSTRUCTION
I r-J
SCALE: 1·. 200'
21,2185
FIGURE 1-2
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2112116
W AT ANA DAM GENERAL PLAN
STAGED CONSTRUCTION CONCE~T
/
RESERVOIR I
EL 200~
I
'"Tl
C)
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:IJ
m -' w
SUSITNA HYDROELECTRIC PROJECT
STAGED CONSTRUCTION PRESENTATION
STAGED CONSTRUCTION TRANSMISSION LINES
STAGE m
FAIRBANKS
KNIK ARM
ANCHORAGE
--EXISTINO INTI!RTI~
.,........,.. WAT ANA INITIAl OAW
·--• DEVIL CANYON
·--···• WATANA HIOH DAW
"TI
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c
:0
m
_.
I •
SUSITNA HYDROELECTRIC PROJECT
STAGED CONSTRUCTION PRESENTATION
CROSS SECTION THAU THE DAM
ST AQE I-WAT ANA INITIAL OAW
RESERVOIR EL. 218! y
L EL 220!
STAQEJII-WATANA HIGH DAM
FIGURE 1-5
SUSITNA HYDROELECTRIC PROJECT
STAGED· CONSTRUCTION PRESENTATION
WATANA SPILLWAY CROSS SECTION
RESERVOIR EL. 2185
FERC LICENSE CONCEPT
-----~r+-~ B
STAOEXOOEE
WA T ANA INITIAL DAM
Ground
Sutface
Ground
Surtac•
A -A
B-B
,
C> c
:D
rn
.....
I
(J)
SUSITNA HYDROELECTRIC PROJECT
STAGED CONSTRUCTION PRESENTATION
W AT ANA SPillWAY RAISING
------·~'-· B
RESERVOIR
EL. 2000
STAGE :X OGEE
WA T ANA INITIAL DAM
RESERVOIR EL. 2 185
WATANA HIGH DAM
Ground
Surtac•
B-B
-n
(;)
c
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m
Mr. Ja~• !. Di1chinger
Project M.an.ager
AlaaLi Power Authority
334 Welt 5th Avenue
Anchorage, Alaak& 99501
Subject : Sueitna Hydroelectric Project
External Reviev Panel
Engineering Sub-Panel Meeting
Report No. 2
Dear Mr. Diachinger:
April 16, 198S
1.8.2/9.3 .3
This letter i1 to tranamit Report No. 2 of the External Reviev Panel,
Engineering Sub-Panel for the Suaitna Hydroelectric Project prep4red
by the underaigued member•.
A;/)ev H.
~Peck
pd
!ncloaure
1. INTRODUCT10N
SUSITNA HYDRO!L!CTRIC PROJ!CT
UT!RNAL RIVI~ PA.Nn
!NCih~!RINC SU!-PAN!l MEETING
R!PORT RO. 2
April 16, 1985
The underaigned three memmbera of the !xtern.&l Review Panel met in
Anchorage on April 15 and 16, 1985 to conaider a 1erie1 of de1ign refine-
ment1 to the Project licente applicAtion. Priz.ry emphaai1 vaa given to
ataged conatruction of the project. In addition, inform& tion vu pra-
aeoted on the project achedule, aome aapecta of the project layout, and
future exploratory v o rk.
pal mattera presented.
2. STAGED CONSTRUCTION
Tbia report preaenta our vieva oo the princi-
A proposal wu pr esented to cooatruct ifataoA Dam in tvo ltagea, firat
(Suge I) to operate vith the reservoir at El 2000, and aecond (StAge
III) at a fin&l elevation of 2185. Devil Canyon D«e vould be conatruct-
ed (S~ge II) at an intermediate tim.e. The a.dvantagea of ataged con-
initiaL fin&nci&l comm.i t111ent of 1 true tion
the StAte,
agree that
lii.Ate coat.
vere indica ted al reducing the
and alloYing more fluibility
the propoaal \IOU ld accompliah
with StAge III invea t:ment, will
in aeetina local growth. We
theae objec:ti.,.ea.
be higher.
'Ibe ulti-
Technically, the propoul incl udea A modification of the internal %oni ng
of ifatana D.m to allow raiaing the dam aafely and ec onomically, and deep-
ening the spillway and approach channel to accommodate the reservoir at
the Stage I elevation.
M3730
850416
The c o re of the modified croll aection hu been incline-d upatreaa to
r~uce the 01cu nt of thell material, required for ttabil it y of the SUit
II da,., that vould be tubmeri~ by the Stage 1 pool and therefore mu tt be
placed durin& Stage I con1truction. Wben the daa ia rai1~, all the
addition.l fill can thu• be placed in· the dry vith only a ~ri.ef, modeat
lowering of the· reaenoir. We reaard thia modification to be appro-
priate. It involve• no adveru effect• on the ufety of either the
Stage I or St.a&e III daa, and no unutual conttruction operation• durin&
rai1ing. We vould anticipate that further D:>difi~tioo1 of t h<-. <.roll
aection vill be found advaotaaeou• aa more detailed info~tion ia devel-
oped re&arding the borrov uterialt.
The tpi llway and approach channel mutt be deepened &.bout 200 feet for
operation during Stage I. lc our judpent the quality of the rock vill
per'lllit the deeper excavation vith . ufety vbeo deliitled vith 1uitabl1t
alopel and ber'llll, and vith th' antici.patioo that more than routine rock
reinforcement vill be required to meet local condition• that may be dia-
closed by ob servation and i!Jstru oentation . w-hen the da11 it raised, both
the power intake and apillway atructure1 vill require uteo1ion upward.
The conce?tual 5cheoet described to u1 appear rea1onable.
3. PO\/ERBOOS!
In the Panel' 1 report of Aug-uat 1983, we wrote that rHent atudie1 had
ahovn aigoificant co•t advantage• for a turface powerhooae at compared to
the underground layout pre1ent&d ia the featibility report . It vaa alto
mentioned that the 1urface alternate required aome ujor open cutt, the
colt of wbich were difficult to a11e11 becau1e of the lack of aub1urface
infor-aatio'Q in thi1 are.&. It it 1till our view that the outdoor power-
boule duig-n hu uay advantagea principally becauu it avoid• the mAjor
unko ovn• inherect in the excavation of three large und erground chamber:~
and numerou1 tunnel• and ioteraection• vbich it not without probltl:ll
even in the best rock cooditioaJ, We recognize that c o nsiderable weight
vas given
feasibility
to the seasonal advaatagel of underg ou nd excavation in
report. However, experience with similar ttructure•
the
i a
Canada hat shovn th .lt outdoo r conttructioo can continue efficiently
t hrougho ut the winter with proper protection of the vorkt.
K.3 7 30. 1
8S0416
At pruent, there are three deep borin&• ia the riabt abut111ent in tbu
aeoeral area o! the propoted chambeu. While much of the cere indicate•
favorable rock cooditiont, there it ample evidence of clay-filled jointa,
altered diorite, and n&ll •hear zonet . Uoder tbeu condition•, the
rock cannot be u1umed to be a relatively bomoaeneout mat a but rather a
rock potteuin& numeroua planu of veuneu, the aeom.etry of vbicL i.a
unknown at thia tiae.
Geotechnical invutiaationa for final duian vould requue 1everal addi-
tional borin ga and an exploratory adit vboae total length could be in the
range of 2000 feet. Tbia proaraz vould be expenaive and require a ma;or
block of time on the overall explorati<>n acbedule. l..xploration for the
outdoo:-l&yout vould require relatively abort b<>rioga principally to
determi ne the depth of overburden and pouibly tvo or three abort a.dita,
vhoae total length vould probably not exceed 150-200 feet.
In conclusion ve believe that the 1urface powerbouae -.lternate baa aiani-
ficant coat advantagea and s ho uld be studied in 1110re detail by the !':o ~i
oeer. An urly decit i oo o n the preferred l ayout would re•ult i t: a
redirection to the pr o posed exploration pro gram.
4. SCHEDULE
An overall tcbedule of explo ration, dea i gfl and construction, includ in g
detail on tupport facilitiea , wat preten t ed. Tbia schedule thov• fin1t
power on line in 1997, 12 yeara frolll nov. !'be tchedale ia conatrained
by the decition to do only support facil i ty (acceta and camp) exploration
and study be!ora pove r ulu aareementa are obtained, and to do virtua l l .r
n o conatruct i on of acceu, c'!-•P or ~nunent vorka before the FE R1=
1 i c eoae b at been iuoed , A two-year period it thovn between it luanct!
o f the F'E RC licente and co~m:~eocement of fint ~rm.anent vork at the
di version tu ooeh. Total conttruction time of the ~nunent . workt ia
s ho wn as se v en and one-h alf yeara to first generation.
MJ730.2
850416
We aaree that the impoeed re1traint1 are reaeonable and appropriate. We
vould recommend, however, that con1truction of tbe temporary airetrii)
ebould be advanced at leaet a year (to mid 1987) to minimize acce11 and
eupport co1ta for exploration vork, and that exploration ahould be accel-
erated vitb u much accompliehed in 1986 and 1987 u pouible in the
predui111 eta&e before FERC liceneina. \'e hel that cuch of the e-xplo-
ration muat be completed before the Baru-lbuco aeueral project duian
me.morandum it final, and moet completed before feature deaian 111e111oranda
are begun. Such exploration it alto required to develop reliable colt
e1tim.ate1. Watana ia an important major project and eite data are •till
quite limited.
Tbe •even and one-half year eon1truction 1chedule for penunent worlr.a
1eem1 exceuive. !ued on our e-xperience on other 1imilar projecta in
aimilar enviroamentl, it i1 our pre•ent judgment that tbil 1cbedule can
be 1bortened by at lea1t one year.
We a ls o believe that the tvo-year interval between iuuance of the F!RC
licenu and start of diver1ion tunnel con•truction can be reduced by
aevera 1 month I.
5. !XPLORA TION PRO GRAM
Additional exploration vae done in 1984 at the reque1t of FERC. Eleven
boring• were drille<! in the Filll, channel, propoeed uoderaround pover-
bouae, and the tpillvay and diver1ion tunnel outlet•. Durin& thil meet-
ing Harza-!baaco pre1ented a ecbedule for the overall e.xploration program
vhich 1hov1 vork beina done for the 1upport facilitiu in the 1ummer of
1985. !eai nn.ina io urly 1986 and continuina euentially throuah 19 89,
exploration it done for accu1 road a, the airatrip, and all civil vorka
i ncluding divertion, the dam, required open cut•, and waterway•.
At this time , however, no document i 1 available 1hovi.ng the required
exploration for each project feature. As vu uplained, the producti o n
of such a plan i • not part of the Eng i nee r 's current work assignment. We
M.3730.3
850416
are concerned that, vitbout such a detailed plan, the exploration could
proceed in a manner which is not JUaranteed to produce the required
info~tion at the appropriate time.
our report of August 1983.
We upreased aimilar concerns in
We recou=.end that APA reconsider their current poaition regardin& the
expenditure of funds for engineering efforts. In our opinion the proj-
ect would benefit greatly from a carefully oraani&ed plan of uploration
which incorporates all available geotechnical information and speci-
fically mentions the addi tioual infonu tiou required for duigu.
It vu tentatively agreed that the next meeting of the !agineer Sub-Panel
vill be held October 1 -4, 1985, vith arrival in Anchorage September 30.
K3"30 .4
850416
Aodrev B. Merritt
Ralph ! • Peck
April 15, 1985
0900-0915
0915-0930
09 30-1000
1000-1015
1015-1030
1030-1100
1100-1130
1130-1200
1200-1300
1300-1415
1415-1430
1430-lSOO
IS00-1530
1530-1600
1600-1700+
April 16, 1985
0900-1200
1300-1400
1400-1430
SOSITNA HYDROEL!C!RIC PROJ!C!
!'ITt R NAL R.! VI !il P A.Nl1.
ME!TING ON S!AGED COHS!RUC'!IOR
Apri \ 15 and 16, 1985
Sixth floor Conferen~• looa
AG!NDA
Introduction• -Opening R~rka
Sutitna Project Description
Project M4ater Sch~ule
Project Statui
a) Licenaing Effort
b) Engineering Effort
Engineering Update
a) Design Refinement•
b) 1984 Exploration Progr&m
c) Design Memorandum Concept
Lunch
Staged Cooatruction Concept
1985 Engineering Work !ffort
a) Staged Conltruction
b) Watana Support Faci1itie•
Kuter Plan
c) Wat&na CLap Expan1ion
d) Future Geotechnical
!nvea tigatiool
DiiCUIIlOD
Consultant• Prepare Report
Ou tbriefing
Future Involvement of Conau1tantl
J. !. Diacbioger
& J. c. Stafford
c. D. Craddock
c. D. Craddock
w. !. L&raoo
w. !. Llr•on
c. D. Craddock
M. P. Bruen
c. o. Craddock
C. D. Craddock
C. D. Craddock
C. D. Craddock
C. D. Craddock
M. P. !rueo
Consu 1 tanta
Conaultanta
J. B. Diacbinger
& C. D. Craddock
)1)740.1
SUSITNA HYDRO!L!CTRIC PROJ!CT
!.IT!R.NAL UVI ~ P ANn
!NGIN!!RING SUB-PANlL M!!T1NG
REPORT NO. 2
Attendee• April 15, 1985
Dr. R.a1pb !. Peclt
Dr. Aodrev B. Merritt
Mr. Jamea w. Libby
James !. Dischinger
John C. Stafford
M. P. Bruen
c. D. Craddock
D. J. Du clr.
J. L. Ehaaz
w. !. Lara on
P. R. Sa:muolia
c. F. \fbi tehead
A. Zaaara
Conaultant
Conaul tant
Conaultant
A1aau Power Authority
Alaau Power Authority
Barza-Ebaaco
Barr.a-Ebaaco
Haru-Ebaaco
Rarza-Zbaa co
Har:ta-Ebaaeo
Ha r :ta-!ba • eo
Harz:a-!baaeo
Raru-l'll&ICO
I Project Coats
ALASKA POW!R AUlllORITY
SYSITNA HYDROELECTRIC PROJECT
STAGED CONSTRUCTION
PROJECT COSTS AND !CONOHICS
Supplement 2
Feasibility level costs of the Susitna Project have been estimated based on
the FERC license concept and on the staged concept. A c o st comparison of
the tvo concepts shows that full development of the staged con c ept is more
expensive than the n:ac license con c ept as sh owu below. However, Stage I
Watana of the staged concept is significantly less expensive than the Watana
stage of the FERC li c ense concept as indicated in Table 2-1.
Stage
I lolatana
II Devi 1 Canyon
Subtotal
Ill Raise Watana
Total
Cost Different i al
TABLE 2-1
PRO JECT COSTS
($ MILLION 1982)
FERC License
$3,371
1,47 5
$4,846
$4,846
Staged
Co ns tru e ti o n
$2,528
1,492
$4,020
1,270
$5 '290
+$444
Table 2-2 includes a more detailed summary cost comparison of the FERC
license concept versus the staged concept.
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1
II !conomica
An econom1c analyaia of the stag ed Suaitna project has shovn that it ia
somewhat leas attractive economical l y than the FERC license concept, but ia
still significantly lower in coat than the least-coat thermal alternative.
The benefit-coat ratios of the FERC license concept compared to the least-
cost thermal alternative and the staged concept compared to the least-coat
thermal alternative are essentially the same as th o se presented to the Power
Authority Board in February (i.e., 1.5 aod 1.4, respectively).
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2
Item
Land & Land Righ~a
Powerhouse
Da~, Reservoir & River Diversion
Power Generation Equipment
Roads, Rail and Air Facilities
Electric Transmission Facilities
Construction Facilities & Misc.
Total Direct Costs
Contingency Allowance
Subtotal
Licensing, Engineering,
& Administration
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850421}
Total Project Coat
TABLE 2-2
PROJECT COSTS
($ MILLIONS 1962)
Staged Constru
Stage 1 Stage 2
Watana Devil
!1. 2000 Canyon
32 22
75 72
947 561
71 67
191 119
294 113
279 154
1,889 1,108
272 160
2,161 1,267
367 225
2,528 1 ,492
tion Concept P!llC Liceose
Stage 3 Total -Vat ana
Watana Stages !1. 2185 &
!1. 2185 1 to 3 Devi 1 Canyon
19 73 73
21 168 144
589 2,097 1,928
36 174 112
51 361 332
118 525 487
153 586 491
987 3,984 3,626
142 574 533
1,129 4,557 4,159
141 733 687
1,270 5 ,290 4,846
ALASIA POii!R Atri'BORI'l'Y
SOSITNA HYDRO!L!CTRIC PROJECT
STAGED CONSTRUCTION
POWER AND ENERGY PRODUCTION
Supplement 3
Under the staged construction acheme, the initial War:sna dam is about 180
feet lover than that propoaed in the F!RC license concept. This result• in
lover head and leu flov regulation capability at Watana. The lover head
reduces the Watana pover output, vhile the reduced reservoir storage reduces
both the Watana and Devil Canyon eoerr generation. After raising the
Watana project (Stage III), the power and energy generation from the two
concepts are identical. Table 3-1 provides a comparison of power and energy
production for the two concepts.
A distinct advantage of the staged construe tion concept i a its abi 1 i ty to
more closely match the expected Railbelt loads without developing excess
capacity. Figures 3-1 and 3-2 demonstrate this effect. Figure 3-l shows
the relation between Railbelt peak power demand and installed capacity for
the least-coat thermal alternative.
Figure 3-2 shovs the pover demand and installed capacity relations for the
Sus i tna case. ~th the FERC 1 ic ease concept and the a taged concept are
shovn. !xceaa reserve capacity e~ista vith the Susitna project during ita
early years. The reserve capacity more closely matches system requirement•
under the staged concept than the FERC license concept. This is especially
true for the period 2002 through 2008.
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1
ALASU POIJ!i AUTHORITY
SUSITHA HYDROELECTRIC PROJECT
STAG!D CONSTRUCTION
FINANCIAL ANALYSIS
Supplement 4
The ttaaina of the Suaitna Project not only provide• the aaeana to better
mat._:, . · '! load requirements of the Railbelt utilitiea, but it also reduces
required rate stabilization funds. With the lover Watana Da11l, in the
initial atagee, fever bonds are required to fund the construction of the
first two stagea. However when Watana ia raiaed to ita ultim.ate height,
inflation and real coat increases act to increase the overall bonding
requirements of the staged concept versus the FERC licence concept.
The bond si~ing analysi1 is based on the construction cash flow developed by
Harza-Ebasco and the assumptions 1 is ted on Table 4-1. It is important to
note that the analysis is based on the bonds having tax-exempt status and
therefore a lover interest rate. Because over 25 percent of the Project
output will be sold to non-exempt entities, the only way for the bonds to
have tax-exempt status is thrJugh specific: legislation by the U.S. Congress
exempting the Susitna Project (as was done for Bradley Lake)', State legisla-
tion authorizing the REA cooperative utilities to reorganize into public
utility districts, or State legislation authori~ing the Power Authority to
direct bill the consumers in the railbelt area for costa associated with the
Suaitoa Project. Even though the Project has been found to be economically
feasible, the utilities' system costs with t he Project are higher than the
alternative in the early years due to the high capital costa of a hydro-
electric project. The staged approach reduces the capital costs during this
period, and the amount required to bring the utilities' coats down to the
alternative is correspondingly :educed.
After reviewing the revised construction coats, we have found the required
rate stabilization to be in the same order of magnitude as presented
previously to the Board. As can be seen in Tables 4-3 and 4-4, the three-
stage concept reduces rate stabilization from over $1.1 billion to $500-750
million if interest earnings are retained in the fund and fro11l $4.5 billion
to $2.6 billion if they are not retained. Absent such rate stabili~at i on,
the utilities' consumers would be faced with significant rate shock.
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850429
!ABL! 4-1
BOND SIZING ASSUMPTIONS
o General Inflation Rate -6.5 percent
o Bond Interest Rate -10.0 percent
o Reinvestment Rates:
-short-term -9.0 percent
-long-term-11.0 percent
o Amortization Period -35 years (level debt service)
o Bond proceeds will be used to fund construction costs, licensing costa,
debt service reserve, working capital, and reserve and contingency.
o First bonds issued after FERC license issued and all monies expended to
date are reimbursed and de posited into the Rate Stabilization Fund.
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Bond Size:
I WATANA
II DEVIL CANYON
SUBTOTAL
III RAISE WAT~~
TOTAL
Annual Debt Service:
I WATANA
II DEVIL CANYON
SUBTOTAL
III RAISE WATANA
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850429
TOTAL
TA.BL! 4-2
BOND ISSUE SUMMARY
(MILLIONS)
FERC
LICENSE
CONCEPT
$12,300
7,000
$19,300
$19,300
$ 1 '280
720
$ 2,000
$ 2,000
STAGED
CONSTRUCTION
$ 8,600
7,000
$15,600
8,400
$24,000
$ 890
720
$ 1,610
870
$ 2,480
T~L! 4-3
RAT! STABILIZATION COHT&I8UTIOH
(MILLIONS)
FERC STAGED
LICENSE CONSTRUCTION
YEAR CONCEPT CONCEPT
1985 $ 100 $100
1986 200 200
1987 200 200
1988 200 100
1989 200
1990 200
1991 40
$1,140 $600
CONCLUSION : A TOTAL STATE CONTRIBUTION IN 7HE ~~GE OF $500 to $750 ~ILLION
WILL MEET RATE STABILIZATION NEEDS
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850429
YEAR
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
200 3
2004
2005
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850429
$
TABU 4-4
STAT! CONTRIBUTION
COMPARISON OF PAY IN AND PAY OUT OF FUNDS
(MILLIONS)
FERC LICENSE CONCEPT StAGED CONSTRUCTION
RATE RATE
CONTRI-StA.BILI-CONTRI-STABILI-
BUT ION ZATIOH BUT ION ZATION
(PAY IN) (PAY OtJT) (PAY IN) (PAY OtJT)
100 100
200 200
200 200
200 100
200
200
40
250
54 0 270
550 240
510 220
450 180
410 150
740 460
670 42 0
550 381)
80
$1 ,140 $4.500 $600 $2,570
I. Introduction
ALASKA POWER AUTHORITY
SUSlTNA HYDROELECTRIC PROJECT
STAGED CONSTRUCTION
ENVIROh~NTAL ANALYSIS
Supplement 5
Analyses have been made of the environmental implications of the staged
concept for the Susitna Project. These analyses considered the
potential environmental effects of the following factors identified as
major differences from the FERC license concept:
1. Smaller reservou volume and reduced storage capacity for the
Stage I Watana reservoir.
2. Decreased flow stability for Stage I, and to a lesser extent for
Stage II in comparison to Stage Ill and the fERC license concept.
3. Lower downstream r1ver te'llperatures (abo ut l"C) and greater tee
cover development with res •.1ltant water level 1ncreases.
4. Reduced area of inundated land for the Stage I ·~atana Reservoir
which delays the loss of wildlife habitat and cultural resources
due to inundation.
5. Possible need for different borrow areas aod quarry sites for
Stage III development with atteodent 1ncrease in wildlife and
cultural res o urce impacts.
424981
850426
6. Increaaed total time required for completion of the project vould
prolona conatructioo related impacta on wildlife, aa vell aa
aocioeconomic impacta.
Findinga
In general, analyaea of the differencea between the staged and FERC license
concepti reveals no significant impacta which would effect Suaitna'a overall
environmental fuaibility. Aa detailed belov, there are both poaitive and
negative differential impacta associated witb the staged concept, most of
which are judged to be insignificant. The major exception, increased
overtopping flows into side slough salmon habitats in the middle river, is
an impact alrea~1 identified for the FERC license concept, albeit at reduced
frequency. Aa such, it has already been accounted for in the project
mitigation planning process and can be avoided by increasing the extent of
slough habitat protection.
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2
II. Retervoir Operation, Temperature and Ice Studiet
Su111111ary
Retervoir operation vat aimulated for Stage• I, II, and III. Reservoir and
river temperature analyse• and river ice aimulationt were made for a
representative c!imate year for Stage• I aad II.
These studiet of retervoir operation, reaervoir temperature, river
temperature and river ice were made to compare the enviroamental effecta of
ataged concept with the F!RC license concept, At summarized in Figure• 5-l
through 5-6 and Tables 5-l and 5-2, the changes resulting from the staged
concept would be:
1. Higher suiDIDer flow• and lower winter flow• in Stage t than vi th
the FERC license concept.
2. Greater ice cover and higher winter water l eveh in the river
below the Project in both Stages t and II.
3. Appr o ximately two weeks delay in the formation of a reservoir 1.ce
cover (from mid November to late November).
Stage Ill of the staged concept and the final stage of the F!RC li cense
concept would be the same.
Rt servoir Operation
Stage t of the staged concept has a smaller reservoir storage volume than
the FERC license concept. Less water can be sto red in the reservoir for
424981
850429
3
vioter operatioa aod the reaervoir operatina plaa for t h e ataged c oncept
att~pta to take advantage of the required higher au~D~Der flova to generate
eneru. The ruult ia that average aummer flova are about 4000 cfa. higher
and average winter flova are about 2000 cfa. lover than vith the F!RC
licenae concept.
For Stage II the Watana reservoir vould fill earlier in the sul!lller than in
the c ue for Stage t. Stage II flova would be very similar to the F!RC
license concept.
Simulation cf Stage III reservoir operation indicate• it would be the ume
as the final stage of the FERC license concept. Fl o ws at all timea of the
year are nearly identical.
Reservoir Te mperature/Ice
Stage I reserv oir t emp erature /ice simu lati on s s ho w the o utfl <"v temperatures
to be nearly identical to the FERC l i cense c o ncept in the s ummer. Winter
temperatures, h o wever , are r e duced fr o m the FERC li c e n se co ncept b y a bo ut 1•
to 1.5°C. Although this difference is slll.111 its significan c e is 1n the
additional ice pr odu c tion which would occur d o vnstream of the pro ject.
There are No apparent r e asons for the redu c tion in winter t e mperatures.
1. More flov is passed through the reservoir tn the summer carrying
heat with it, thus leaving less heat available for the winter
season.
2. The reservo1r tee cover te nds to f o rm about No weeks later than
vitb the FERC license concept. It is believed this is t he result
of the additional viod induced mix i ng in the smaller reservoir.
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4
SUSITNA HYDROELECTRIC PROJECT
COMPARISON OF PEAK CAPACITIES AVAILABLE
3000~----------------~----------------~-----
--FERC LICENSE
CONCEPT
~b~~i~T '~!':5;i';$~Jt!
2000~------4-------~~~~~----~~~--~
RAILBEL T PEAK
POWER DEMAND
0~-------L--------~-------L--------L-----~
1984 1992 2000 2008 2018 2024
YEAR
TA!LE 3-1
COMPARISON OF CAPACITY AND ENERGY
FERC LICENSE CONCEPT:
WATANA HIGH DAM
DEV1 L CANYON
STAGED CONSTRUCTION
STAGE
STAGE
STAGE
400782.3
850425
1-WATANA INITIAL
2-DEVI L CANYON
3 -~ATANA HIGH DAM
DAM
INSTALLt:D
CAPACITY
(MW)
1020
600
1620
520
600
500
1620
AVG ANNUAL
ENERGY
( GWRR)
3500
3400
6900
24 70
3120
1310
6900
SUSITNA HYDROELECTRIC PROJECT
NON-SUSITNA ALTERNATIVE PEAK DEMAND AND CAPACITY
3000
1ooof=~ ... =··'='::~F=~~--~~~~-r-------i-----l
'"---+ RAILBEL T PEAK
POWER DEMAND
0~------~--------~-------L--------L---~ 1984 1992 2000 2008 2016 2024
YEAR
,
' c
J
ii
" .
Tbe ratio of eurface area to volume ie about 30% higher for Stage
t Watana Reservoir. Tbe delay in ice cover ie important becauae
the reeervoir ice cover inaulatu the reservoir and reduce• heat
lou .
In Stage It, eummer outflow temperature• are eimilar to the F"ERC license
concept. Winter temperature• are about 0. 5• to 1•c leu than for the FERC
1 icense concept. Since flove are about the ume for Stage II and the FERC
licenee project, the uin reason for the vinter temperature difference is
the delay in reservoir ice cover formation.
River Temperature
S i mulation studies shov that rLver temperatures vould follov the same trend
as reservoir temperatures. That is, they would be similar in summer to the
FERC license concept and about 1•c colder in winter.
River Ice
Results of the ice modelit:g studies show that because of the colder winter
reservoir outflow temperatures the ice cover for both Stage I and Stage II
would extend further upstream and cause higher river levela than the FERC
1 i cense conc ept.
Computer runs for Stage I suggest an ice c over about three mi lea further
upstream than for the FERC license concept. This ice cover , in turn ,
result• in an i ncrease in water levels in the river. Water levels were uo
to four feet higher in an eight mile reach of the river between river miles
115 and 123 and about the same elsewhere. Without mitigation Slough 11
would be overtopped with Stage I but not with the FERC license concept.
Melt out of the ice cover would be delayed by approximately three weeks.
424981
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5
C0111puter runa for Stage Il reaulted in an ice cover about seven a~i lea
further upatream at ita maximum progression with water levela generally two
feet higher between river milea 101 and 126. Slough• 8A and 9 would be
overtopped with Stage I~ where they ~re not overtopped in the FERC license
concept. Melt out would be delayed by about 1 week.
Stage III river ice would be similar to the FERC license concept.
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6
III. Aquatic Habitat Studie1
The estimated "vith project" flov1, water temperature• and tee processe•
discussed above were compared between Mtural, F!RC licente concept and
the staged concept condition• for a preliminary asses!111ent of impacts on
aquatic habitats due to project operation.
This comparison hat shown only alight changes in anticipated project
impacts. These changes can be a.meliora::ed by changes in the mitigation
plan. The major change necessary would be the need to increase the height
and extent of artificial benns included in mitigation plana to protect aide
slough habitats ~rom overtopping flows during the winter.
Plow
Smaller reservoir storage capacity during Stages I and II would result in a
reduction in flow control during the summer and reduction of water available
for power generation during the winter. Summer flows would be greater and
less stable during Stages I and II than for the FlRC license concept. This
would produce a slightly greater quantity (area) of rearing habitat for
fish using the mainatem and side channels, however, the loss of flow
stability would reduce ita quality. These factors should balance one
another and result in apprvxillloltely equal production from summer rearing
habitats for either the staged or PERC license concepts.
Plows during August aod September would be higher during Stages I and II
than for the FlRC license concept. These higher flows would provide
improved access conditions for spawning chum and sockeye salmon to move into
side slough spawning habitats. However higher, more extentive artificial
benns would be required to protect these chum and sockeye salmon habitat•
424981
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7
from overtoppina flova, in p&rticul&r to protect the habitat ~dification
atructuru vbicb vould be in place for aait igat ion purpotet. At discussed
belov, theae aaore extenaive protective bermt are also required to pre·1ent
overtopping flova in vinter.
Winter flovs vould be .over during Stage I and II than for the FERC license
concept. The difference between flowa in August and September and flowa
through the winter would affect over-vinter survival of salmon eggs in the
side slough apavn ing area a. Decreaaing flows during the fall would cause
dewatering and f.-eezing of some ,..,awning locations. These flov decrease•
would be greater during Stage I and II than for the FERC 1 iceose concept;
however, both cases are an improvement over natural conditions. The
improvement would simply be less vith Stagea I and II so there would be a
loss of benefit until Stage III is operational.
Temperature
Water temperature during Stages I and II would be similar to those during
t h e FERC 1 icense concept for the mid-summer and fa 11 period. Temper at urea
through the winter and early summer would be slightly less (l-l.S°C). Such
small temperature differences between the staged and unstaged projects ue
not expected to effect survival of the evaluation species or production from
aquatic habitats.
Ice Processes
The reduced winter vater temperatures during Stagea I and II would result to
a longer duration of ice conditions, further upstream progression of tee on
the river, greater ice thicknest and greater "river staging".U due to ice
11 River staging aa used herein refers to increases in water level in the
river. This is different from use of the term staging in relation to
Project construction.
424981
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8
11 c01Dpared to the FERC 1 icenae concept. Thue condition a would have the
aruteat iaapact on over-.,intering and incubation aitu in aide alougha.
Biaher river ataging vould 1ncreaae the frequency vith which the natural
existing upstream berms on the alougha would be overtopped and ID4inatem
vater be passed through the alouah habitata.
Theae winter overtoppina event• are conaidered deleterious to juvenile
aalmon over-wintering and salmon egg• incubating in the side slough
habitats. The placement of artificial berms at the heads of important side
sloughs baa been included in mitigation plana to protect these habitata
during ope rat ion of the unstaged project. Protect ion of these habitats
during Stages I and II would require higher, more extensive artificial
benns.
Inundated Tributary Habitat
Some minor benefits would be re<.lized in that the Stage I Watana reservoir
vould not inundate as much tributary mouth and tributary stream habitat
vhich includes some good to excellent grayling habitat ~n a number of the
streams draining into the proposed reservoir area. The Oshetna River, one
of the better grayling streams 1n the area would not be affected at all by
the Stage I Watana reservoir. This habitat would be lost eventually, of
course, vhen the Stage Ill project is constructed.
424981
8501.26
9
IV. Wildlife and Botanical Reaourcea
SummAry
A deciaion to pursue the !ta&ed concept for the project vould, in general,
reduce the net project impacta on wildlife and botanical resourcea during
the initial stagea. The net effect would be positive from the standpoint of
wildlife and botanical resource• for the time between Stagea I and III. The
potential impacta of the development of Borrov Area F. a high quality
wildlife habitat area (which would eventually be rehabilitated). are not
considered to outweigh the benefits of; 1) delayed habitat lou, 2) more
time for local wildlife populations to adapt to the habitat loaa and
movement restrictions caused by the reservoir; and 3) more time to refine
and implement required mitigation programs, and the other advantages of the
staged approach.
Habitat Inundation
The major changes with the staged concept would be that approximately 17,000
acres of wildlife habitat, which would be inundated by the Watana High Dam,
would be preserved for roughly 10 years. Vegetation on the 17,000 acres of
preserved land consists moat ly of forests. On the south side of the
impoundment black spruce predominates with interspersed vertical bands of
tall shrubs. South-facing slopea on the north shore of the impoundment have
greater areal excent and more diverse vegetation patterns. White spruce 1s
the most common forest type, although open mixed forests (consisting of
white spruce and paper birch) and black spruce forests are also represented.
Birch shrub and mixed low shrub areas are present, especially near the mouth
of Watana Creek.
Much of th ia land area consists of the gentler sloping port ions of
habitat than
the
the eventual impoundment, which represeota higher
steeper canyon walls for most wildlife species.
424981
850426
10
quality
Extensive tracts on both
1ide1 of the Watana Creek confluence on the north aide of the impoundment
and band• of land on both 1ide1 of the impoundment between Wa c:ana and
Deadman Creek1 repruent about half of the 17,000 acre1. These area•
provide valuable wildlife habitat, particularly for mooae and bla c k bear.
In the caae of the black bear, staged develoment would delay the lou of
important denning and foraging habitat. The Watana Bigh Dam would inundate
about 55% of the known den aitea in the vicinity of the Watana impoundment,
while the Stage I Watana Dam would inundate only 35% of these den sites.
Another advantage of the staged developa~ent ap;>roach would be that local
wildlife populations would be allowed to adapt to the habitat lou and
movement restrictions resulting from impoundment, in atagea over a greater
period of time. This could be particularly valuable to anim.ala that are
expected to suffer carrying capacity losses such aa moose and black bear,
since overpopulationa of adjacent habitats and the accompanying overutiliza-
tion of adjacent forage resources, would also occur in stages over a greater
period of time and may result in less damage to these adjacent habitats.
Although significant impacts to Dall sheep use of the Jay Creek mineral lick
are not expected to result from the Watana Bigh Dam impoundment, the Stage I
Watana Dam would produce even fever problema relative to the Jay Creek
lick.
Big Game Movement
The width of the Stage I Watana Reservoir would also be significantly
narrower than the Watana Reservoir in the FERC license coucept. The Watana
initial reservoir would be leaa than one mile vide throughout the majority
of ita length, and would thus represent leaa of a barrier to big game
movements than the reservoir in the FERC license concept.
424981
850426
11
Rapt on
The delayed development of the Staae III Watana Oa111 vould also benefit
raptora. One golden eagle and one bald eagle ne1ting locution occur oear
the el. 2200 contour and ID&Y be ia~pacted by the development of Stage III.
However, the Stage I development vould produce a re•ervoir level lov enough
to prevent impact• to these nesting locations during the approximately 10-
year period between Stage 1 and Stage II I development. Thi• vould provide
additional time for developing and implementing the artificial nest program
to mitigate for lost raptor ne ~! locations .
Impacts of Longer Project Construction Schedule
A more subtle, but real, advantage of the staged concept approach i • that
data collected and experience gained through the monitoring of construction
and operation effects and mitigation success during Stage• I and II vould
permit refinements to construction, operation, and mit i gation plans during
Stages II and III so that the ultimate impacts on vildlife and botanical
resources would be lessened.
One potential disadvantage of the staged approach is that the construct i on
period is lengthened, thereby increasing the length of the period that
wildlife populations are exposed to construction-related wildlife
disturbance and mortality factors. Howe v er, the level of disturbance during
Stage III development would be less than during the earlier stages due to
the reduced m.agni tude of the construction effort and the presence of an
existing infrastructure and support facilities devel o ped during Stage I.
More importantly, assuming that public acces• is restricted during the
entire construction period, the elimination of public access during Stage
III and the resultant elimination of a variety of associated disturbance and
mortality factors would more than compensate for the construction-related
factors.
424981
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12
Borrow Areaa
The moat important diudvantage of the ltaged developa~ent approach ia the
probable requirement to obtain Stage III borrow material• from Borro w
Area F.
Borrow Area E, a primary source for materials for Watana Dam in the FERC
license concept and for Stage I of the st•ged concept, would be partially
inundated by the Devil Canyon Reservoir during Stage II construction,
increasing the likelihood that Borrow Area l would need to be used during
Stage III (use of Area F is cons i dered un l ikely for the FERC license
concept). Borrow Area F occupies about 5 miles of the middle stretch of
Tsusena Creek fr om just above the high waterfall to Tsusena Butte. It
includes areas adjacent to the stream and extending up to abcut 1500 ft.
away . This area provides important habitat for a variety of wildlife
including moose, black bear, brown bear, and other species associated with
tributary stream bottoms. Because of the areal extent of this bottom area
outside of the imp o undment zones, extensive use of Borrow Area F could
substantially increase the total amount of high quality wildlife habitat
disturbed by the project. Alth o ugh bo rr ow area rehabilitation would be
conducted, habitat impacts would be experienced for many years.
On the positive side, the staged concept probably would reduce the amount of
caterial required fr0111 QuarrJ Site A because all quarry material for Stage I
would be obtainable through excavation of the deeper spillway requ i r e d for
the staged concept. Although the habitat value of this area is not high ,
the general level of habitat disturbance and loss in the general project
area would be less.
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850426
lJ
v. !ffectl of Staging on Cultural Reaourcea
SUDID&r]
The primary effecta of staging on cultural reaource vould b~ to reduce, at
least initially, the number of archeological site• impacted through
construction and reservoir flooding, and allov more time for study and
implementation of mitigation plana. Both are significant positive benefit•
frat~~ the cultural reaource• atandpoint. Since ltaging doea not alter the
schedule or design of the Devil Canyon Dam and Reservoir, ita effect u
essentially neutral.
Use of Borrow Areas
The only potential effect noted is that Borrow Area E uy be partially or
completely covered by the Devil Canyon impoundment prior to Stage III Watana
construction. Alternative borrov sites uy have to be used for thia latter
construction. This could have ao impact oo other archeological remains. In
particular, the likelihood of utilizing Borrow Area F for Stage III
construction would be high. As discussed below, this is an archeologically
important area.
Staging of the Watana Dam construction would make a greater difference to
cultural resources, though on balance the effect• are positive. As the
construction schedule in Stage I would be speeded up for a completion date
of 1996 instead of 1997, there would be somewhat less time available in
which to implement mitigation plans. However the scaled-back construction
of Stage I would require less borrow, resulting in leu damage due to
removal of fill. this is particularly important in Borrow Area F (the
Tsusena Creek area), which contain a total of nine recorded archeological
sites (see Table 5-3).
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850426
14
Reduced Area of Inundation
Tbe Stage t impoundment level of el. 2000 would ruult in inundation of 49
recorded archeological eitee (see Table 5-4). Thi1 i• one-third fewer than
would be flooded perm.anently by reservoir level of el. 2185 in the PERC
license concept. The 24 sites between el. 2000 and el. 2185 contour1 would
be av~i lable for etudy for a much longer period under the staged concept
than in the FERC license concept. Staging would allow additional time for
implementation of mitigation plana for these 24 sites, as Stage Ill
construction i• nol scheduled for completion until 2008.
A final consideration concerns how staging vould affect sites adjacent to
but outside the actual project area. Adjacent sites are defined as those
lying within one-half mile of a project boundary. Though not affected
directly, these sites are subject to impacts due to ancillary construction
activity, improved access, greater likelihood of erosion, and increased
traffic. A lower reservoir level would reduce the ·eservoir perimeter
temporarily leaving more archeological sites outside the one-half mile zone.
It should be noted, however, that the adjacency distance u arbitrarily
defined, so that other factors such as topography may be more significant.
Nevertheless, approximately 15 adjacent sites would fall outside the one-
half ruile zone for a el. 2000. reservoir level. This represents 31 percent
of the sites defined as adjacent in the PERC license concept.
424981
850426
15
V1. Socioeconomic Analyeie
!mploy~ent and Population
In general, the etaged concept vould •lightly decrease pealt conatructiou
employ111ent to about 2,950 (in 1994) and extend the length of employment to
the year 2008. Tbe projected construction emplv1111ent pealt for the FER•:
license concept vould be about 3,000 (in 1994) and emplo1111ent would end il
2002 (see Table 5-5).
Population increase• generated by the Project generally follow the same
pattern as Project induced emplo1111ent. The magnitude and duration of
population impacts would therefore foll c v the trends of employment impacts.
The duration of impact would be boger by five year• under the staged
project but the magnitude at pealt would not be significantly different .
Community Facilities and Services
Impacts on demand for facilities and services are a consequence cf
population impacts. Since the magnitude of population impacts are similar
in both the staged and ITRC license concepts, impacts on communit:t
facilities and services are likely to be similar. Tbe major differenctl
would be that impacts would o ccur more gradually and last longer for thE
staged concept. The demand levels from 2002 until 2008 would be well belo10
peak demand for either the FERC license or staged concepts.
Prolonging the duration of Project-induced demand would have on~ positive
effect. That is, it delays or reduces excess capacity of facilities that
would be built to meet pt!ak demand. Since most collllllunities in the impact
ar~?s ~-·:!!constantly increasing baseline populations, the fad;,ities con-
structed to serve peak project related demand would evet.tually be needed
after the Project construction ends. The period of excess capacity, between
the time peak project demand ends and baseline demand catches up, produces a
financial burden for maintenance and operation coete for underutilized
facilities.
burden.
30411
8 50429
The staged concept would reduce or eliminate this financial
16
TA!L! 5-l
SOSITNA HYDRO!L!CTRIC PROJECT
MAXIMUM SIHULAT!D RlV!R S!AG!S
WINTER 1981-82
PLOW CAS! !-VI, INYLOW MATCHING
2001 AND 2002 !N~RGY DE}{ANDS
Stage I
High Watana +
High
Threshold Watana
River Mile Elevation Alone
Watana + Devil Canyon
Slough or
Side Channel
Devil 50' Drawdovo
Whiskers
Gash Creek
6A
8
HSII
HSII
Curry
Hoose
8A West
8A ~ast
9
9 u/s
4th July
9A
10 u/s
11 d I •
ll
17
20
21 (A6)
21
22
101.5
112 .o
112.3
114.1
115.5
115.9
120.0
123.5
126.1
127. 1
129.3
130.6
131.8
133.7
134.3
135.3
136.5
139.3
140.5
141.8
142.2
144.8
367
On known
(Opland)
476
482
487
Unknown
Unknown
57 3
582
604
Unknown
Unknown
651
657
UnknoWll
687
UnknoWll
7 30
747
755
788
LRX-3 Ice Front Starting Date
Maxi~um tee Front Extent (River Mile)
Melt-out Date
12-28
134
3-2J
Canyon 3 Levels
!3691
456
459
476
~
520
548
571
581
[ill]
616
627
649
655
667
682
714
728
746
7 52
783
12-30
126
3-19
l37o I
459
461
~
522
553
57 3
584
606
619
630
649 t
655 \
667
682
714
728
746
7 52
785
12-29
133
4-l
• c==J Indicates locations where maximum river stage equals or
exceeds a known slough threshold elevation
• All river stages in feet
30421/TBL
850426
m&XliDlliD up-
stream exten
of i c e fro nt
Slough or
Side Channel
Whiskers
Guh Creek
6A
8
KSII
MSII
Curry
Moose
8A West
8A East
9
9 u/a
4th July
9A
10 u/s
11 d/a
11
17
20
21 ( A6)
21
22
TABU 5-2
SOSITNA BYDRO!L!CTRIC PROJ!CT
MAXIMUM SIKULAT!D iiV!i STAG!S
WATAAA ONLY: 2001 !KERG'! DEMAND
CAS! !-Vl FLOWS, INFLOW-MATCHING
WINTER 1981-82
River Mile
101.5
112 .o
112.3
114.1
115.5
115.9
120.0
123.5
126.1
127 .1
129.3
130.6
131.8
133.7
134.3
135.3
136.5
139.3
140.5
141.8
142.2
144.8
'n\reshold
!levation
367
Onltnovu
(Upland)
476
482
487
Unkoovu
Onknovu
57 3
582
604
Unknovu
Unltnovu
651
657
Ooltoovu
687
Onltnovu
7 30
747
755
788
High
Wa taDA
Iofl-Matcb
IIITJ
458
460
475
~~~I
524
552
i
621
633
654
660
668
684
715
729
747
7 54
787
Ice Front Starting Date 12-28
134
2-23
Maximum Ice Front !xtent (River Mile)
Kelt-out Date
Stage I
Watana
Infl-Matcb
'n\rougbout
12-12
137
4-12
maximUIIl up-
stream uten
of-ice front
• Indicates locations vhere maximum viver stage• equal or
exceeds a knovn slough threshold elevation
• All river stages in feet
30421 /nL
850426
BORROW AR!AS :
A
B
c
D
E
F
G
B
I
J
TABL! 5-3
SITES APP!CT!D !T LICENS! APPLICATION COHSiiUCTlOH
None*
None*
TLM 054, 055, 078, 081, 084, 085, 086, 087, 088,
094,095,096,097,201,211,213
None*
TLM 022, 023, 258
Adjacent to E: 024, 035
TLM 176, 188, 202, 203, 209, 210, 212, 214
Adjacent to F: 164
None*
None*
TLM 034, 178, 259
TLM 080
Adjacent to J: 043, 058, 063, 177, 200, 229, 230,
233
K TLH 030
L Sone*
Devil Canyon Reservoir TLH 023, 034, 178, 252, 253, 258, 259
Adjacent to Devil Canyon Reservoir: 022, 024, 027,
029, 030, 118
*None: No recorded archeological 1itea
424981
850426
TABL! s-4
SlT!S A.FFECT!D !Y STAGED CONSTRUCTION OF WATANA DAM/R!SERVOil
STAG! I (2000' Reaervoir Level)
TLM 033, 040, 043. 050, 058, 062. 063, 065, 072. 075, 077, 079, 080,
102, 104. 115. 194, 199, 200, 216, 220, 221. 222, 224. 22 5, 226, 227,
228, 229, 230, 231, 232. 233, 234. 235, 236, 238. 239, 240, 241, 242,
243, 246. 247, 248, 249, 250. 2 56, 257 ( N-49).
STAGE I II (2000-2185' Reservoir Level)
TLK 039, 048, 059, 060, 061, 119, 126, 169 J 171. 173, 174, 175 , 182,
184. 196, 204, 206, 215, 217. 218, 223, 237, 244, 251 (N•24).
ADJACENT SITES (Within 1/2 Mi. of 2185 Reservoir Level)
TLM 026, 031, 032, 038, 042. 04 7. 049, 064, 073, 074, 076, 12 0. 12 1,
122. 12 3. 124, 12 5. 127, 128, 129, 130, 131. 132. 133, 134 , 135, 136,
139, 140. 141. 142. 143, 14 5. 14 7. 148, 159, 165, 166, 167 .. 177. 18 3.
185, 189, 190, 195, 198 , 207, 219 (N-48).
Sites Outside the One-Half Mile Zone, Stage I (2000' Reservoir Level)
TLM 026, 032, 038, 042, 049, 073, 074, 076, 120, 122, 159, 189, 195,
198, 207 (N-15).
Sites Adjacent to Watana Construction Area
TLM 01!», 018, 160, 165, 166, 167, 172, 192, 197 (N•9)
424981
850426
Curreat Project
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
01
02
03
04
OS
06
07
08
424981
850426
Wataaa
-o-
1,017
1, 512
1,047
1,082
1,776
2,142
2,721
2,069
938
259
-o-
-o-
-o-
-o-
-0-
-o-
-o-
-o-
-o-
-o-
-o-
Devil
-o-
-o-
-o-
-o-
-o-
167
167
321
501
482
1,182
1, 181
1,196
1, 572
74 7
126
-o-
-o-
-o-
-o-
-o-
-o-
TA.BL! 5-5
YEARLY P!Al WORKFORCE
Total Staae 1
-o--o-
1, 017 637
1,512 825
1,047 1, 028
1,082 1,164
1,943 1,384
2,309 1,837
3,042 2. 625
2,570 1, 8 31
1,420 350
1,441 -o-
1. 181 -o-
1 ,196 -o-
1,572 -o-
74 7 -o-
126 -o-
-o--o-
-o--o-
-o--0-
-o--o-
-o--o-
-o--o-
Staged
Staae II Staae 1 II Total
-o--o--o-
-o--o-637
-o--o-825
-o--o-1,028
-o--o-1,164
167 -o-1,551
167 -"o-2,004
321 -o-2. 946
501 -o-2,332
482 -o-832
1 ,182 -o-1,182
1,181 -o-1. 181
1 ,196 -0-1,196
1. 572 -0-1. 5 72
74 7 -o-74 7
126 410 536
-o-842 842
-o-1,055 1,05 5
-o-1,510 1,510
-o-1,446 1,446
-o-1,057 1,057
-o--o--o-
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Molchin Inflow, 1981-1982
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