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SEDIMENT TRANSPORT CHARACTERISTICS
OF SELECTED STREAMS
IN THE SUSITNA RIVER BASIN,ALASKA:
DATA FOR WATER YEAR 1985
AND TRENDS IN BEDLOAD DISCHARGE,1981-85
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UNITED STATES
DEPARTMENT OF THE INTERIOR
GEOLOGICAL SURVEY
SEDIMENT TRANSPORT CHARACTERISTICS OF SELECTED STREAMS
IN THE SUSITNA RIVER BASIN,ALASKA:DATA FOR WATER YEAR 1985
AND TRENDS IN BEDLOAD DISCHARGE,1981-85
by James M.Knott,Stephen W.Lipscomb,and Terry W.Lewis
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"-~JPEN-FILE REPORT 87-229
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Prepared in cooperation with the
ALASKA POWER AUTHORITY
ARLIS
daska Rtl!\()urces library &'Information Services
Ubrary Building,Suite 111
321 f Providence Drive
Ancborage,AK P9S08-4614
Anchorage,Alaska
1987
i
DEPARTMENT OF THE INTERIOR
DONALD PAUL HODEL,Secretary
u.S.GEOLOGICAL SURVEY
Dallas L.Peck,Director
For additional information
write to:
Copies of this report can
be purchased from:
u.S.Geological Survey
Books and Open-File Reports Section
Box 25425,Federal Center
Denver,Colorado 80225
ii
CONTENTS
Page
Abstract.........1
Introduction......1Descriptionofarea....................................................4
Climate................................................................4
Data collection and analysis...........................................4
Sediment discharge.....................................................6
Sediment transport and particle-size characteristics..............6
Suspended-sediment concentration •••••••••••••••••••••••••••••••••6
Relation between suspended-sediment discharge and water discharge.8
Bedload discharge and hydraulic characteristics...................9
Relation between bedload discharge and water discharge............10
Trends in bedload discharge,1981-85...................................13
Bed rna terial.• . . . . . . . . . . . . . • . . . . . . . . • . . . . . . . . . . . . . • • . • • • • . . . . . . . . • . . . . .14
Estimated sediment load................................................14
Summary and conclusions................................................15Referencescited.......................................................16
ILLUSTRATIONS
Map showing location,major streams,and selected stream-
gaging and sediment-sampling stations in the Susitna River
basin.. . . . . . . . . . . . • . . . . . • . • • . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . 2
Figure 1.
2-8.
2.
3.
4.
5.
6.
7.
8.
9-15.
9.
10.
II.
12.
13.
14.
15.
16-22.
16.
17.
18.
19.
20.
Graphs showing sediment-transport curves of suspended silt-
clay and sand discharge for:
Susitna River near Talkeetna ••••••••••••••••••••••••••••••••
Chulitna River below canyon near Talkeetna ••••••••••••••••••
Susitna River below Chulitna River near Talkeetna •••••••••••
Talkeetna River near Talkeetna ••••••••••••••••••••••••••••••
Susitna River at Sunshine .•••••.•••..•••••••••••••..••••....
Yentna River near Susitna Station •••••••••••••••••••••••••••
Susitna River at Susitna Station ••••••••••••••••••••••••••••
Graphs showing relation of mean suspended-sediment concen-
tration and discharge to water discharge for:
Susitna River near Talkeetna and at Gold Creek ••••••••••••••
Chulitna River below canyon near Talkeetna ••••••••••••••••••
Susitna River below Chulitna River near Talkeetna •••••••••••
Talkeetna River near Talkeetna ••••••••••••••••••••••••••••••
Susitna River at Sunshine ••.••••.•••..•.••••••.••••••.•.•.•.
Yentna River near Susitna Station •••••••••••••••••••••••••••
Susitna River at Susitna Station ••••••••••••••••••••••••••••
Graphs showing bedload-transport curves of sand and gravel
for:
Susitna River near Talkeetna ••••••••••••••••••••••••••••••••
Chulitna River below canyon near Talkeetna ••••••••••••••••••
Susitna River below Chulitna River near Talkeetna •••••••••••
Talkeetna River near Talkeetna ••••••••••••••••••••••••••••••
Susitna River at Sunshine ••••••••••.•••••••••••••••••••••••••
iii
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
ILLUSTRATIONS--Continued
Page
21.Yentna River near Susitna Station............................37
22.Susitna River at Susitna Station.............................38
23-26.Graphs showing variability of water and bedload discharge
for:
23.Susitna River near Talkeetna.................................39
24.Chulitna River below canyon near Talkeetna...................41
25.Talkeetna River near Talkeetna...............................43
26.Susitna River at Sunshine....................................45
TABLES
Table 1.Summary of streamflow and sediment data for selected stations
in the Susitna River basin...................................46
2.Suspended-sediment data for selected stations in the Susitna
River basin,October 1984 to September 1985..................47
3.Hydraulic and bedload data for selected stations in the
Susitna River basin,October 1984 to September 1985..........48
4.Bed-material data for selected stations in the Susitna River
basin,May to September 1985.................................49
5.Water discharge and estimated sediment loads at selected
stations in the Susitna River basin,October 1984 toSeptember1985...............................................50
iv
CONVERSION TABLE
For the convenience of readers who prefer metric (International System)units
rather than the inch-pound units used in this report,the following conversion
factors may be used:
Multiply inch-pound unit
inch (in.)
foot (ft)
mile (mi)
square mile (mi 2 )
acre-foot (acre-ft)
foot per second (ft/s)
cubic foot per second (fts/s)
ton,short
ton per day (ton/d)
degree Fahrenheit (OF)
~
25.4
0.3048
1.609
2.590
1,233
0.3048
0.02832
0.9072
0.9072
°C=5/9 (OF-32)
to obtain metric unit
millimeter (mm)
meter(m)
kilometer (km)
square kilometer (km 2 )
cubic meter (m S )
meter per second (m/s)
cubic meter per second (ms/s)
megagram (Mg)
megagram per day (Mg/d)
degree Celsius (OC)
Other abbreviations in this report:
mg/L,milligrams per liter
NTU,nephelometric turbidity units
Sea level:
In this report "sea level"refers to the National Geodetic Vertical Datum of 1929
(NGVD of 1929)--a geodetic datum derived from a general adjustment of the
first-order level nets of both .the United States and Canada,formerly called "Mean
Sea Level of 1929."
v
SEDIMENT TRANSPORT CHARACTERISTICS OF SELECTED STREAMS
IN THE SUSITNA RIVER BASIN,ALASKA:DATA FOR WATER YEAR 1985
AND TRENDS IN BEDLOAD DISCHARGE,1981-85
By James M.Knott,Stephen W.Lipscomb,and Terry W.Lewis
ABSTRACT
The upper reaches of the Susitna River have been considered for development of a
large power-generation system for southcentral Alaska.This report presents a
summary and discussion of sediment and hydraulic data obtained from October 1984 to
September 1985 (water year 1985)at selected sites on the Susitna,Chulitna,
Talkeetna and Yentna Rivers.Sediment data include measurements of suspended-
sediment and bedload discharge,and analyses of particle-size distribution of
suspended sediment,bedload,and bed material;hydraulic data include measurements
of channel width,average depth and velocity of water,and water-surface slope.
Relations between water and sediment discharge are developed for each site.
Sediment loads for water year 1985 were estimated for the Yentna,Chulitna,and
Talkeetna Rivers and for three sites on the Susitna River.About 31 million tons
of sediment were transported by the Susitna River at Susitna Station during the
year.The Yentna and Chulitna Rivers contributed about 21 million tons of sediment
to the Susitna River.
INTRODUCTION
The Susitna is one of the major rivers in Alaska,ranking fifth in drainage area.
The upper reaches of the river have been considered as potential sites for several
large dams and reservoirs.In 1986,plans for large-scale hydropower development
of the upper Susitna River were discontinued,at least temporarily.
This report presents a summary and discussion of sediment and hydraulic data
collected at selected sites in the Susitna River basin in the area between the
proposed damsites and Cook Inlet.Figure 1 and table 1 summarize locations and
availability of data.Subsequent data presented in this report were collected
during the period October 1984 to September 1985 as part of a cooperative program
between the Alaska Power Authority and the U.S.Geological Survey.In addition,
selected data from historical records,data for water years 1981-84 (Knott and
Lipscomb,1983 and 1985;Knott and others,1986),and data collected in 1985 are
used to estimate the total amount of sediment (suspended sediment and bedload)
transported by the major streams in the basin during water year 1985.Relations
between water and sediment discharge are developed for various sites in the basin.
1
3
EXPLANATION
3 ....STREAM GAGING STATION (FLOW AND SEDIMENT DATA)AND MAP NUMBER
4 V SEDIMENT SAMPLING STATION AND MAP NUMBER
DRAINAGE BASIN BOUNDARY
o 10 20 30 40 50 MILES
1-1_-,~...1'-'-1--,,-''---.-,_-',ti~__...LI__---l1
o 10 20 30 40 50 KI LOMETERS
Figure I.-Location,major streams,and selected stream-gaging and sediment-sampling
stations in the Susitna River basin.
•
2
Io
oINSET
DESCRIPTION OF AREA
The Susitna River basin (fig.1)lies on the southern flank of the Alaska Range in
southcentral Alaska.The relief of the basin,which has a drainage area of about
19,400 mi 2 ,is a contrast of steep,rugged mountains towering above wide valley
lowlands.Altitudes range from 20,320 ft at Mt.McKinley to sea level where the
Susitna River empties into Cook Inlet.
Tributaries to the Susitna River are commonly referred to as either glacial or
nonglacial streams.The nonglacial streams are noted for their clarity,even
during intense summer rainstorms.Glacial streams are turbid throughout most of
the open-water season (May through September).Glacial and nonglacial streams in
the Susitna River basin are both characteristically low in turbidity (less than 10
NTU)during most winter months (November through March).The Susitna River and its
larger tributaries are all affected to some degree by glacier runoff.
CLIMATE
The climate of the Susitna River basin is divided into two broad categories
(Searby,1968).The higher altitude parts of the basin are included in the
Continental Zone,where diurnal and annual temperature variations are great.Mean
annual temperatures range from 15 to 25 of (Hartman and Johnson,1978).The
lowlands lie in the Transition Zone,where temperatures are less variable.Mean
annual temperatures here generally range from 25 to 35 of.Mean annual precipita-
tion in the basin ranges from less than 20 in.near the mouth of the Susitna River
to more than 80 in.at higher altitudes (National Weather Service,1972).
Climatological records for the weather station at Talkeetna probably are repre-
sentative of lowland areas.A summary of data for this station (Selkregg,1974)
indicates/that mean daily temperatures range from 38 to 62 of in summer,and from
-9 to 18°F in winter;extremes range from -44 to 85 of.Annual precipitation at
Talkeetna averages 28 in.,about 60 percent of which is rainfall.
DATA COLLECTION AND ANALYSIS
Beginning in 1981,systematic measurements of sediment discharge and stream
hydraulic properties were begun to define the amount and distribution of sediment
transported by the Susitna River and its major tributaries between Gold Creek and
Sunshine (fig.1).In 1981,data were collected at four sites in July,August,and
September.Two sites were on the Susitna River,one at Gold Creek (No.3 on map)
and the other at the Parks Highway crossing at Sunshine (No.12).The remaining
two sites were on major tributaries to the Susitna River,one each on the Chulitna
(No.7)and Talkeetna (No.11)Rivers.
During 1982 the data-collection program was expanded to obtain weekly samples
during the open-water season (May to September).A new sampling site (No.6 on
map)was established on the Susitna River upstream from the Chulitna River
confluence.The stream-gaging station and the monthly collection of suspended-
sediment samples were continued at Gold Creek.Bedload sampling sites (Nos.9 and
4
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10 on map)were established on the Susitna River in 1983 and on the Susitna (No.
14)and Yentna (No.13)Rivers in 1984.Suspended-sediment data have been obtained
for the Susitna River at Susitna Station and Yentna River sites since 1975 and
1981,respectively (Still and Jones,1985).From 1983 to 1985,samples have been
collected monthly with occasional sampling during storm periods.At each site,
data collection included:
1)Suspended-sediment samples
2)Bedload samples
3)Bed-material samples
4)Water-discharge measurements
5)Measurements of water depth and channel width
Selected samples of suspended sediment,bedload,and bed material were analyzed for
particle-size distribution.Streamflow characteristics were defined from data
available for existing stream-gaging stations.At sampling sites that did not
coincide with stream-gaging stations,sufficient discharge measurements were
obtained to develop stage-discharge relations.Summer measurements were made from
a boat;either a cableway or sextant was used to determine stationing along the
measuring section.Winter measurements were made by attaching a sampler to a rod
and lowering the sampler through holes drilled in the ice.
Depth-integrated,suspended-sediment samples were collected using a standard
point-integrating P-61 sampler (Guy and Norman,1970).Samples include those
particles (usually finer than 2.0 mm)transported in the stream between the water
surface and a point about 0.5 ft above the streambed.Two samples were obtained at
each of five selected verticals in the stream cross section (at centroids of flow)
and analyzed to determine average values of suspended-sediment concentration and
the particle-size distribution of sediment in the water-sediment mixture.The two
samples from each vertical profile were generally composited to obtain one
analysis,but in a few instances the individual samples were analyzed.
Sediment transported within 0.25 ft of the streambed was sampled using a bedload
sampler (ReIley and Smith,1971)designed for collecting coarse material (0.25-
76.2 mm).Sampling time,number of sampling points,stream width and depth,and
weight of dry sediment were recorded as a basis for calculating bedload discharge.
Trap efficiency of the sampler was assumed to be 1.0.Characteristics of the
ReIley-Smith sampler and procedures for its use have not yet been fully evaluated.
In the interim,the Geological Survey follows a provisional method of obtaining
samples at about 20 equally spaced verticals based largely on field tests by Emmett
(1980)•
Some of the sediment transported in suspension cannot be accurately sampled by the
P-61 because the lowest depth accessible to the sampler is about 0.5 ft above the
riverbed.Silt-clay concentrations are generally assumed to be uniformly
distributed throughout the total depth of the river and the concentration of this
material near the riverbed (between riverbed and 0.5 ft above bed)is considered to
be approximately the same as that in the sampled zone.The concentration of
suspended sand near the riverbed,however,is generally larger than that in the
sampled zone because sand particles tend to settle toward the riverbed if flow
velocities are not sufficient to keep them in suspension.At least part of the
5
medium to coarse sand fraction (0.25-2.0 rom)moving near the riverbed is trapped by
the bedload sampler (from riverbed to 0.25 ft).
A preliminary examination of the amount of sand transported in suspension and as
bedload suggests that attempting to account for sand that is not sampled by either
sampler would generally increase reported concentrations of suspended sand (table
2)at most sites by about 1 percent.At some sites,however,such as the Yentna
River and the Susitna River at Susitna Station,the amount of sand that is not
sampled is perhaps 10 percent of the total suspended sand.
A few bed-material samples were obtained at each site using a 6-inch diameter pipe
dredge.At some sites,deep water and a swift current,armoring,and the presence
of coarse particles on the streambed made sampling difficult.Although indicative
of the sizes of particles present in the streambed (less than 150 rom),bed-material
data presented in this report may not be representative of actual particle-size
distributions.Surface and sub-surface samples also were obtained where the
streambed was exposed or where water depths were less than 2 ft.These samples,
obtained with a sampler similar to a McNeil sampler (McNeil and Ahne11,1964)are
probably representative of actual particle-size distributions.
Measurements of water depth and channel width at sampling sections were usually
made during bedload measurements.Depths were measured by sounding with the
Re11ey-Smith sampler at 16 to 25 points in the cross section.Stream width was
determined from station markings on cab1eways or from sextant readings.Average
velocity was determined by dividing the rated discharge of the stream by the
cross-sectional area (width x depth).
SEDIMENT DISCHARGE
Sediment Transport and Particle-Size Characteristics
Sediment particles may be transported in suspension,by rolling and bouncing along
the streambed,or as a combination of both.Suspended sediment,as the name
implies,consists of particles that are transported in a stream while being held in
suspension by the turbulent components of the flowing water.Coarse sediment that
is transported on or near the streambed constitutes the bedload.C1ay-and
silt-size particles usually are moved in suspension,while gravel particles move on
or near the streambed.Sand-size particles may be transported either as suspended
load,as bedload,or both.
Suspended-Sediment Concentration
Suspended-sediment data for the period October 1984 to September 1985 are listed in
table 2.During 1985,only two significant storms occurred,and these were small
compared to those that occurred in the period 1981-84.Most samples were collected
during periods of low to moderately high flows.
6
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In July and August,glacier runoff and storms commonly result in high concentra-
tions of suspended sediment for long periods.When a major storm occurs,
suspended-sediment concentrations can increase rapidly to several thousand
milligrams per liter.During warm periods between storms,glacier runoff increases
and concentrations remain high.
The Susitna River near Talkeetna (No.6 on map)and the Talkeetna River near
Talkeetna (No.11)are least affected by glacier runoff;glaciers cover 5 and 7
percent of their respective drainage areas.Sampled concentrations of suspended
sediment at these sites ranged from about 200 to 700 mg/L during July and August
1985.Silt-clay percentages (47-62 percent)are about the same as for sand (38-53
percent).
Spring "breakup"occurred in mid-to late May at most sampling sites.The sampling
dates in May generally reflect the timing of the ice-breakup event within the basin
(table 2).Ice cover on the rivers disintegrates first in the lower basin near
susitna Station.Breakup then generally proceeds upstream and occurs last near
Gold Creek.Concentrations of suspended sediment increase rapidly during the
breakup process and then generally decrease through June.In 1985,concentrations
ranged from about 500 to 1,000 mg/L in May and then decreased to about 200 to 400
mg/L in late June.An exception to this pattern was the station Chulitna River
below canyon,where the higher concentration (l,240 mg/L)of suspended sediment
reflects glacier runoff.The percentages of silt-clay sediment in May and June
(prior to glacier runoff)are generally low (18-52 percent)relative to sand (48-82
percent)at all sites in the basin.
1984 to
from 2
April 1985).
to 21 mg/L,
A few samples were collected in the winter (October
Suspended-sediment concentrations for these samples range
typical of concentrations measured during previous winters.
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The Chulitna River is the most affected by glacier runoff;glaciers cover 27
percent of the drainage area.Summer concentrations of suspended sediment in the
Chulitna River are typically more than twice as high (1,000 to 2,000 mg/L)as those
for either the Susitna or Talkeetna Rivers near Talkeetna.Silt-clay percentages
are significantly higher (63-79 percent)than those for sand (21-37 percent)during
storm and glacier-runoff periods.
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Suspended-sediment data obtained at the sampling site designated Susitna River
below Chulitna River near Talkeetna (map Nos.9 and 10 for the right and left
channels,respectively)are representative of the combined discharge of the Susitna
River near Talkeetna and Chulitna River below canyon near Talkeetna (map No.8).
The site,about 1 mi below the confluence of the Chulitna and Susitna Rivers,
includes two major channels (separated by a stable,vegetated island)and several
minor channels.At this site,the right channel (as viewed looking downstream)of
the Susitna River carries the entire flow of the Chulitna River along with smaller
but varying amounts of "crossover"flow from the Susitna's left channel.
Suspended-sediment concentration and water discharge for the right channel were
several times higher than that of the left channel during July and August 1985.
Suspended-sediment concentrations for the Susitna River at Sunshine ranged from
about 900 to 1,700 mg/L during July and August 1985.Suspended-sediment
7
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concentrations at this site represent the result of the mixing of water from the
Chulitna,Susitna,and Talkeetna Rivers.
The Yentna River,which a drains an area of 6,180 mi 2 (above the gaging station),
is the largest tributary to the Susitna River;Concentrations of suspended
sediment in samples collected in July and August ranged from 600 to 800 mg/L.
Concentrations for the Susitna River at Susitna Station (500 to 800 mg/L)fall
within the range in concentration for the Yentna River and Susitna River at
Sunshine.The percentage of silt-clay material for these three sites was
consistently higher (61-79 percent)than that for sand (21-39 percent).
Suspended-sediment concentrations and water discharge usually decline during
September and October as cooler weather reduces the melting rate of high-altitude
snowpacks and glaciers.In 1985,a moderately large storm occurred during this
period,and sampled concentrations at the sites Susitna and Talkeetna Rivers near
Talkeetna were variable,ranging from 69 to 503 mg/L.Concentrations for the
Chulitna and Yentna Rivers declined substantially below summer values but remained
greater than 300 mg/L in September.By mid-September the percentage of silt-clay
material (34-46 percent)was less than that for sand (54-66 percent)at most sites.
Relation Between Suspended-Sediment Discharge and Water Discharge
A common method for analyzing sediment-transport characteristics at a site is to
construct a relation of sediment discharge versus water discharge.This relation
is usually illustrated as a plot on logarithmic paper and is referred to as a
sediment-transport curve.Data for May to September 1981-84 reported by Knott and
Lipscomb (1983 and 1985),and by Knott and others (1986),and data given in this
report were used to develop sediment-transport curves for the silt-clay and
sand-size fractions of suspended sediment for the Susitna,Chulitna,Talkeetna,and
Yentna Rivers (figs.2-8).Historical data (U.S.Geological Survey,1953-85)were
used to extend the curves for extreme high and low flows.Transport curves of
suspended...sediment discharge were developed by first dividing the total range of
water ..discharge into small increments and then averaging both water discharge and
suspended-sediment discharge for each increment (Colby,1956).For flow ranges at
which the trend of the data points appeared to define a straight-line relation on
logarithmic graph paper,the line of best fit was computed using the least-squares
method.
The relations between water and suspended-sediment discharge,for all sampling
sites in the Susitna River basin,follow a linear-logarithmic trend during the
open-w~er season (May to September).The relation is in the form of the equation:
Q =aQ ,where Q is suspended-sediment discharge,in tons per day;Q is water
d~scharge,in cubfc feet per second;and a and b are constants.The rate at which
sediment discharge increases relative to water discharge is defined by the exponent
"b".The constant "a"can be considered as an indicator of the amount of sediment 1
transported at a given water discharge.For example,if the exponents "b"for two 1
rivers were similar,the river having the larger value of "a"would transport more
sediment at the same water discharge.
8
raIl.sport curves of silt-clay discharge indicate that silt-clay discharge increases
~t~water discharge at exponential rates ranging from 2.37 to 3.18.The largest
exponential rates occur for sites on the Susitna River below Chulitna River,
stisitna River near Talkeetna,and Talkeetna River near Talkeetna.The increase in
~:f..lt-clay discharge with increasing water discharge is considerably smaller for
sites on the Yentna River and Susitna River at Susitna Station.
Transport curves of suspended-sand discharge indicate a greater variation in
exponents than those for silt-clay discharge.Exponents range from 1.55 to 3.54.
~~~rend of decreasing exponents with distance downstream from Talkeetna also occurs
for the transport of suspended sand.Exponents for sites on the Yentna and Susitna
RIvers near Susitna Station are also small relative to those for upstream sites.
TraIl.sport curves of total suspended-sediment discharge for winter periods (October
t?April)(figs.9-15)were prepared from historical data obtained in U.S.
9=ological Survey Water-Data reports (1953-85).Suspended-sediment data available
for winter months are few,and most relations between water and suspended-sediment
discharge for October to April periods are not well defined.
Bedload Discharge and Hydraulic Characteristics
Bedload and hydraulic data obtained for the sampling sites during the 1985 water
year are summarized in table 3.Bedload data are expressed both as discharge in
tons per day,and in terms of their particle-size distribution in percent finer
than the indicated sieve size.
Winter samples (under ice cover)of bedload have been collected several times at
all sites --in March 1983,in February 1984,and in February and April 1985.
Bedload discharges computed from samples collected in February and March probably
indicate near-minimum rates of transport,because these are the months of minimum
st~eamflow.Winter bedload discharges at the upper sites --Chulitna,Susitna,and
Talkeetna Rivers near Talkeetna --ranged from zero to about 15 ton/d.Downstream
from the confluence of the Chulitna and Susitna Rivers,bedload discharge is
significantly greater.Bedload discharge at the lower sites during February and
April ranged from 15 to 130 ton/d.Bedload at all sites was predominantly sand
during the winter.
During the 1985 open-water period (May to September),bedload discharge of the
Susitna River near Talkeetna ranged from 67 to 590 ton/d (table 3).During this
same period,water discharge ranged from 14,300 to 46,400 fts/s.The transported
material consisted primarily of sand (84-100 percent)and lesser amounts of gravel
(0-16 percent).
Bedload discharge of the Chulitna River below the canyon ranged from 3,590 to 6,990
ton/d and water discharges from 14,300 to 39,000 fts/s.During low-flow periods in
September,the particle-size distribution of bedload on the Chulitna River tended
toward a high percentage of sand (51-66 percent).Gravel was the primary
constituent of the bedload (58-73 percent)during spring and the summer.
9
During the open-water period,bedload discharge of the Talkeetna River near
Talkeetna ranged from 384 to 1,850 ton/d for water discharges ranging from 5,900 to
17,100 ft 3 /s.Typically,bedload at this site consisted mainly of sand (53-92
percent)•The percentage of gravel exceeded that of sand only during the high
flows of May 28 and August 15,1985.
Bedload discharge at Susitna River below the Chulitna River was measured separately
in each of two major channels about 1 mi downstream from the confluence.Bedload
transport rates in each channel roughly correspond to rates measured at upstream
sites on the Chulitna and Susitna Rivers near Talkeetna.A large part of the water
discharge,however,crosses over from the Susitna River and mixes with flow
originating in the Chulitna River.Bedload transport rates in the right channel
are similar to those measured at the upstream Chulitna River site.Transport rates
ranged from 680 to 5,530 ton/d with gravel constituting about 50 to 90 percent of
the bedload.The percentage of sand was higher than gravel only on September 4
during a low-flow period.Bedload rates in the left channel are typically much
lower than those in the right channel and are similar to those measured at the
SusitnaRiver near Talkeetna.Bedload ranged from 135 to 1,030 ton/d,with sand
composing about 80 to 90 percent of the material.
Bedload discharge of the Susitna River at Sunshine ranged from 584 to 2,590 ton/d
at flows ranging from 46,900 to 76,500 ft 3 /s.No samples representative of very
high or very low flows were obtained during the open-water period at this site.
During the summer,sand generally constituted from 60 to 90 percent of the bedload
discharge.The percentage of gravel was larger (56-69 percent)on September 16 and
May 31.
Bedload discharges during 1985 for the Yentna and Susitna Rivers near Susitna
Station were considerably higher than those for any of the other sites.The Yentna
River transported from 4,360 to 13,300 ton/d of bedload,most of which was sand
(85-96 percent).The Susitna River at Susitna Station transported bedload at rates
ranging from 4,690 to 20,900 ton/d.This material was also predominantly sand
(62-93 percent).
Relation Between Bedload Discharge and Water Discharge
It is generally assumed that bed material is furnished to a stream in quantities
that are larger than the capacity of the channel to transport the material and that
the stream will transport the load at capacity (Einstein and Johnson,1959).Most
theories of bedload transport are based on the assumption that bedload discharge is
a function of water discharge,and that as the discharge increases the bedload
discharge will also increase.A few recent studies,however,suggest that if the
supply of transportable sediment is not uniformly distributed along a reach of the
river an inconsistent relation between bedload transport and water discharge can be
expected (Klingeman and Emmett,1982).Klingeman and Emmett discuss the occurrence
of transport-loop relations during transient runoff events as bed material is moved
from storage areas (large supplies of sediment)to sampling sites.Meade (1985)
discusses the movement of bedload sediment as a wavelike pulse by which bedload is
moved from storage areas through riffles to storage areas farther downstream.
10
bedload-transport relations for streams in the Susitna River basin,formerly
thought to be poorly defined,seem to agree very well with the relations described
by the above authors.Bedload-transport data for all the sampling sites in this
1 study show a varying degree of scatter,depending on the supply of transportable
sediment at the sampling site,the supply available in upstream storage areas,and
water discharge.
r
1 Transport curves of bedload discharge were generally developed by first dividing
n the total range of water discharge into small increments and then averaging both
r water discharge and bedload discharge for each increment (Colby,1956).If the
"trend of the data points appeared to define a straight-line relation on a
l logarithmic scale,the line of best fit was computed using the least-squares
;;method.If the scatter was large and no reasonable relation was apparent,a
f loop-type relation was assumed and an average relation was developed by visually
+fitting a line to the data.
e Bedload-discharge data for the study period (1981-85)were divided into components
f of sand and gravel discharge.The relations developed for each component are shown
in figures 16 through 22.
d Bedload-discharge data representative of the upper Susitna River were obtained at
r two sites.Most of the data were collected at Susitna River near Talkeetna (No.6
on map)during the period 1982-85.Three measurements of bedload discharge were
d made at Gold Creek (No.3)in 1981.The river reach between the sites and the
d reach extending about 10 mi upstream from'Gold Creek consists of a straight,
uniform channel or split channels separated by stable,vegetated islands.The few
gravel bars present are unstable and shift after floods (R and M Consultants,
a 1985).The riverbed is generally armored by cobbles and small boulders.The line
a of best fit,computed by the least-squares method,provides a reasonable relation
d between bedload and water discharge for the Susitna River near Talkeetna (fig.16).
s
d Bedload-discharge data for the Chulitna River also were obtained at two sites.In
1981,the measurements were made at the gaging station.In 1982,the sampling site
was moved to a location 4.0 mi downstream.The Chulitna River,upstream from the
site "Chulitna River below canyon"(No.7),flows through a narrow canyon for about
8 mi.The river varies in width from about 300 to 600 ft and flows in a relatively
straight,single channel.The channel is constricted by bedrock in the narrow
s reaches and armored with cobbles to small boulders in the wider reaches.About 100
t to 150 ft of the channel width (center)commonly consists of sand and gravel.
t Upstream from the canyon the river divides into numerous braided channels.The
s braided reach varies in width from 1,000 to 7,000 ft and extends for a distance of
d about 20 mi.Storage of sand-and gravel-size material in the braided reach is
.e estimated to be in excess of 100 times that within the canyon reach.
e
e Bedload data for the Chulitna River site have an extremely large scatter (fig.17)
e relative to other streams in the basin.The distribution of the data is unusual in
d that bedload appears to increase with increasing discharge at relatively low flows,
)decreases abruptly,increases at higher flows,decreases abruptly again,and
,s finally increases again at still higher flows.This cascading-type of pattern,
which occurs for both sand-and gravel-size material,suggests that the supply of
this transportable bed material is limited and that the river generally transports
11
sand and gravel at less than capacity.If the extreme variability in bedload
discharge is assumed to be due largely to changes in supply,the river will
transport sand and gravel at "above average"rates (upper curve on top part of fig.
17)when the supply is large and at lower rates (lowest curve on top part of fig.
17)when the supply is small.Recent work by Emmett and Klingeman (1982)seems to
apply to the Chulitna River.Their studies indicate that,if a large part of the
transported bed material originates in upstream storage areas,the occurrence of a
transient runoff event can temporarily deplete the stored bed material at the
sampling site and bedload transport will decrease.When sufficient time passes,
bedload transport increases and large amounts of bed material continue to move past
the sampling site for a long time into the streamflow recession period.
The previously discussed concepts of a variable supply of bed material were used to
develop some approximate relations between bedload discharge for the Chulitna River
site.The scatter of data for this site is such that the definition of one or more
relations is subject to individual interpretation.
Three relations are estimated for the transport of sand and gravel at the Chulitna
River site.The transport relations for high flows (greater than 29,000 ft S /s)
assume that the supply of sand and gravel at the sampling site is rapidly depleted
during storm events and that a minimum supply exists.The transport curve for high
flows is probably indicative of bedload transport in the canyon if no large storage
areas existed upstream.
River-reach characteristics upstream from the site "Susitna River below Chulitna
River"are complex.The reach upstream from the right channel (No.9)consists of
numerous braided channels that shift daily.The reach is about 4,000 ft wide and 8
mi long.The reach upstream from the left channel (No.10)is narrower (2,000 ft)
and less braided.It extends for a distance of only about 2 mi above the
confluence of the Susitna and Chulitna Rivers.
Bedload data for the Susitna River below Chulitna River (fig.18)have a large
scatter,but the data indicate a rough trend of increased bedload with increases in
discharge.The relations between sand and gravel discharge and water discharge
were obtained by least-squares analysis.
Upstream from the sampling site the Talkeetna River follows a meandering course
through unconsolidated glacial-moraine deposits.The flow is generally divided
into several channels.Gravel bars are numerous,but do not account for a large
supply of bed material.The nearest source of a large supply of bed material
occurs in braided reaches near glaciers about 40 to 50 mi upstream.
The scatter of bedload data for the Talkeetna River (fig.19)shows several of the
same trends as described for the Chulitna River.The supply of sand and gravel is
limited and bedload discharges decrease and appear to follow a separate relation
for flows greater than 17,000 ft S /s.Sand discharges seem to occur in separate
groups that follow similar trends depending on the available supply.Three
relations between bedload and water discharge are estimated for the transport of
sand and one relation is estimated for the transport of gravel.
12
The
5,0
con
one
con
Wit
be
dat
to
ass
tra
shi
sto
Onl
Sus
the
bed
for
The
wer4
of c
of 1
the
vall
COil
Meal
des(
trar
SUP!
at ~
sedj
Thi::
reCE
samJ:
and
Sand
sugg
peri
gene
tran
(fig
low
occu
ad The river reach upstream from Susitna River at Sunshine varies in width (1,000 to
11 $,000 ft)and is braided from about 1 mi upstream from the sampling site to the
g.confluence of the Chulitna and Susitna Rivers.The sampling section is leveed on
g.one bank and is confined by riprap boulders on the other.Most of the riverbed
to consists of sand and gravel.
l1e
a With a seemingly inexhaustible supply of sand and gravel upstream,the river would
l1e be expected to transport this material at near capacity rates.The scatter of
s,data,however,is large (fig.20)and suggests an inconsistent relation of bedload
st to water discharge.The average relations developed for this site are based on the
assumption that the higher bedload discharges are due to non-uniform erosion or
transport conditions upstream from Sunshine.These conditions may include major
to shifting of river channels or bed material waves originating from large upstream
er storage areas.
re
Only 2 years of bedload data are available for the sampling sites on the Yentna and
Susitna Rivers near Susitna Station.Only one relation is developed for each of
~a these sites.There are,however,indications that inconsistent relations apply to
s)bedload discharge.The average relations are based on the same assumptions used
ed for the Susitna River at Sunshine.
gh
ge
TRENDS IN BEDLOAD DISCHARGE,1981-85
~a The transport relations developed for four sampling sites (figs.16-17 and 19-20)
)f were used in conjunction with records of daily water discharge to construct graphs
8 of average sand and gravel discharge for the period 1981-85 (figs.23-26).Values
t)of measured bedload discharge plotted on the graphs show reasonable agreement with
~e the computed values during extended periods of low to moderate flows.Measured
values show poor agreement with the computed values,however,for periods
coincident with and following major storm runoff.
ge
Ln Measured bedload discharges appear to follow a cyclical pattern similar to that
ge described by Klingeman and Emmett (1982)for bedload transport behavior during
transient runoff events.Their analysis indicated that in river reaches where the
supply of transportable sediment was not uniformly distributed,the sediment supply
se at a sampling site downstream from an area in which large amounts of transportable
ed sediment were stored would be depleted during the rising stage of storm runoff.
ge This depletion in supply would result in reduced bedload discharges.During the
3.1 recession stage of storm runoff,the supply of transportable sediment at the
sampling site would be replaced by sediment scoured from the upstream storage area
and bedload discharges would increase.
~e
Ls Sand and gravel data for the Chulitna,Susitna,and Talkeetna Rivers (figs.23-25)
m suggest that the available supply of this material is severely depleted during
te periods of high runoff.Measured bedload discharges for these periods are
ee generally a small fraction of average bedload discharge values computed from the
)f transport relations.Sand and gravel data for the Susitna and Talkeetna Rivers
(figs.23 and 25)agree reasonably well with the computed values during periods of
low to intermediate flows.Above-average discharge of sand and gravel occasionally
occurs at the Talkeetna River site following major storm runoff.
13
Extreme cyclical fluctuations in sand and gravel discharge at the Chulitna River
site (fig.24)are attributed to the effects of huge sediment storage areas located
about 8 mi upstream from the sampling site.Depletion of the sediment supply seems
to occur rapidly at the sampling site during periods of high runoff.Enrichment of
sediment supplies generally occurs a few weeks after peak flow and reaches a
maximum about 20 to 40 days after the peak.
Longer term changes in sand and gravel supply also seem to occur after extremely
large floods such as those that occurred in July and August 1981.Following
periods of severe depletion in July and August,the sediment supply increased
substantially in September 1981 and generally remained high through July 1982.
Another large storm in July 1982 resulted in another cycle of sand and gravel
depletion during high runoff.The supply of sand and gravel was then increased in
August 1982.Addi tional cycles of depletion and enrichment are indicated for
September 1982 through June 1983,August and September 1983,August and September
1984,and August and September 1985.
Cyclic trends in bedload discharge are also apparent fOT the Susitna River at
Sunshine (fig.26).The closer proximity of the sampling site to upstream storage
areas,however,probably results in less depletion of sand and gravel supplies
during periods of high runoff.Supplies of sand and gravel at all four of the
sampling sites appear to have increased in June 1982 and then followed a general
decline ill succeeding years.
BED MATERIAL
were collected during 1985.Analyses of these
4.Representative samples of bed material were
in submerged parts of the channels because the rivers
and swift for direct access to streambeds.Samples considered
of particles finer than 128 mm,however,were obtained at most of
sampling sites.
ESTIMATED SEDIMENT LOAD
The sediment load passing a site is commonly expressed in terms of weight (short or
metric tons)or volume (acre-feet or cubic meters).Sediment loads may be
estimated by different methods,depending on the amount and type of available data.
If daily records of streamflow are available,but sediment discharge has·been
measured only infrequently,the method most commonly used requires defining a
relation between instantaneous sediment discharge and water discharge and applying
this relation to daily values of water discharge.This method was used to estimate
suspended-sediment load for this study.
Relations between bedload and water discharge are inconsistent at most sites and
development of more than one relation is subjective.The inconsistent relations
are believed to be due to non-uniform supplies of bed material in river reaches
upstream from the sampling sites and limited supplies of material.
14
e/most critical relations concern the amount of sand and gravel transported
ring high flows.The supply of this material appears to be limited at all of the
mpling sites near Talkeetna.Extrapolation of the average transport curves
suIts in estimates of bedload discharge that are 4 to 17 times that of the
asured data during periods of high flow.Estimates of monthly bedload discharge
r these sites are based on the assumption that bedload discharge does not
crease above the upper limit of the transport curves shown in figures 16-19.
second type of inconsistent relations concerns the occurrence of high bedload
charges during recession flows.These high bedload discharges probably occur
ring periods of moderate flow as well as during maj or floods.A detailed
ssessment of the frequency of occurrence or duration of these high bedload
ischarges is beyond the scope of this study.The transport curves,representative
f>higher than average bedload transport (figs.17,19-20),were not used to
stimate monthly bedload discharge for the 1985 water year.
Estimated total sediment loads for the 1985 water year are summarized in table 5.
It Monthly and annual loads are given for four sites on the Susitna River and for one
~e site on each tributary,the Chulitna,Talkeetna,and Yentna Rivers.
:1
y
.g
:d
r
d
s
f
a
le Total sediment load (sum of suspended load and bedload)of the Susitna River
II increases from 3.3 million tons in the middle reach of the river near Talkeetna to
about 31 million tons near the mouth at Susitna Station.The Chulitna,Talkeetna,
and Yentna Rivers account for most of the increase,contributing 7.9,1.8,and 13.6
million tons,respectively.
Suspended-sediment load of the Susitna River and its tributaries ranged from about
;e 88 to 98 percent of the total load in 1985.A large part of the suspended load
re consisted of silt-clay size material (table 5)which is easily held in suspension
rs and generally is transported large distances at nearly the same velocity as the
~d flowing water.It is unlikely that any appreciable deposition occurs in the reach
)f from Talkeetna to Susitna Station as the monthly amount of silt-clay size material
transported at upstream sites is about the same as that transported at downstream
sites.Similar comparisons for suspended-sand loads also show a fair agreement in
the amount of this material transported at upstream and downstream sites.
Bedload,which generally consists of medium sand to very coarse gravel (0.25-64.0
Dr mm)at most sites,is subject to large variations in transport rate,depending on
be flow characteristics and the available supply of coarse sediment.
a.
en
a
ng
te
Annual bedload transport at the various sampling sites in
70,000 to 1.6 million tons.Annual bedload was smallest
Talkeetna and largest at Susitna River at Susitna Station.
accounted for about 75 to 80 percent of the total bedload.
1985 ranged from about
at Susitna River near
Medium to coarse sand
nd SUMMARY AND CONCLUSIONS
ns
es The total sediment load of the Susitna River near its mouth (at Susitna Station)
during the 1985 water year was estimated to be about 31 million tons.This
estimate and estimates of sediment load for other sites on the Susitna River and
15
its tributaries are based on measurements of suspended-sediment and bedload
discharge made during the 1981-85 water years.Suspended-sediment relations for
1981-85 are representative of similar hydrologic conditions --most data were
collected during 4-day sampling periods.Suspended-sediment data collected prior
to 1981 were used for various sites where the 1981-85 data were insufficient to
develop an adequate relation between water and suspended-sediment discharge.
Estimates of total sediment load for the major tributaries to the Susitna River and
the Susitna River near Talkeetna site account for most of the sediment passing
Susitna Station.The Yentna and Chuli.tna Rivers contributed about 21 million tons
of sediment,or 70 percent of the total for the 1985 water year.The Susitna and
Talkeetna Rivers accounted for an additional 5 million tons during the same period.
The combined drainage area of the above sites is about 17,000 mi 2 ,or 88 percent of
that for the Susitna River at Susitna Station.
Relations developed between water and suspended-sediment discharge generally
provide a reasonable fit to the data except where too few data are available
(winter relations).The most reasonable relations are shown as solid lines.
Relations based on sparse data are shown as dashed lines.
Relations developed between water and bedload discharge are less consistent than
those for suspended sediment.The inconsistent relations are believed to be due to
nonuniform and (or)limited supplies of bed material in river reaches upstream from
the sampling sites.At some sampling sites,the supply of material is temporarily
depleted during transient flows and bedload discharges decrease dramatically.
Bedload discharges increase after maj or storms and commonly reach maximum values
weeks after peak flows.
REFERENCES CITED
Colby,B.R.,1956,Relationship of sediment discharge to streamflow:U.S.
Geological Survey open-file report,170 p.
Einstein,H.A.,and Johnson,J.W.,1959,The laws of sediment transportation,in
Applied sedimentation:New York,John Wiley,p.62-71.
Emmett,W.W.,1980,A field calibration of the sediment-trapping characteristics of
the Helley-Smith bedload sampler:U.S.Geological Survey Professional Paper
1139,44 p.
Guy,H.P.,and Norman,V.W.,1970,Field methods for measurement of fluvial
sediment:U.S.Geological Survey Techniques of Water Resources Investiga-
tions,Book 3,Chapter C2,59 p.
Hartman,C.W.,and Johnson,P.R.,1978,Environmental atlas of Alaska (2nd ed.):
University of Alaska,Institute of Water Resources,95 p.
Helley,E.J.,and Smith,Winchell,1971,Development and calibration of a pressure-
difference bedload sampler:U.S.Geological Survey open-file report,18 p.
Klingeman,P.C.,and Emmett,W.W.,1982,Gravel bedload transport processes,in
Gravel-bed rivers:New York,John Wiley,p.141-169.--
Knott,J.M.,and Lipscomb,S.W.,1983,Sediment discharge data for selected sites
in the Susitna River basin,Alaska,1981-82:U.S.Geological Survey Open-File
Report 83-870,45 p.
16
d
r
e
r
o
d
g
s
.d
f
y
.e
Ln
:0
1m
-y
!s
In
3.1
3.-
):
e-
in
es
Ie
1985,Sediment discharge data for selected sites in the Susitna River
basin,Alaska,October 1982 to February 1984:U.S.Geological Survey Open-
File Report 85-157,68 p.
ott,J .M.,Lipscomb,S.W.,and Lewis,T.W.,1986,Sediment transport charac-
teristics of selected streams in the Susitna River basin,Alaska,October 1983
to September 1984:U.S.Geological Survey Open-File Report 86-424W,73 p.
,W.J.,and Ahnell,W.R.,1964,Success of pink salmon spawning relative to
size of spawning bed materials:University of Washington,Fisheries Research
Institute Report 469,14 p.
ade,R.B.,1985,Wavelike movement of bedload sediment,East Fork River,Wyoming:
Environmental Geology and Water Science,v.7,no.4,p.215-225 •
ational Weather Service,1972,Mean annual precipitation--inches:National
Weather Service [Alaska],map.
and M Consultants,1985,Susitna hydroelectric project effects on navigation:
Alaska Power Authority Document No.2746,112 p.
earby,H.W.,1968,Climates of the States --Alaska:Environmental Data Service
ESSA,Climatology of the United States,No.60-49 •
elkregg,1.L.,editor,1974,Alaska regional profiles '--southcentral region:
University of Alaska,Arctic Environmental Information and Data Center,255 p.
till,P.J.,and Jones,K.V.,1985,Alaska index:Streamflow and water-quality
records to September 30,1983:U.S.Geological Survey Open-File Report
85-332,173 p.
Geological Survey,1953-85,Water resources data for Alaska,water years
1952-84:U.S.Geological Survey Water-Data Reports,published annually.
17
50 1 I I I I 1 IIII 1 I 1 1 1 I I I I
1000 10 ,000 100,000 1000 10,000
WATER DISCHARGE,IN CUBIC FEET PER SECOND
100
500,000
~
~1952-85
•1982-84}
[]1985
0 Stream
Os+c Silt-clay
100,000~Osand Sand discharge
>-«0 t -~>-a:w «
0-f:
U)/-a:
z Qs+c =6.97 x 10-10 0 3 .00 Osand =2.07 x 10-12 0 3 .54 w
0 0..
I-er.
Z Za
w l-
e>z
a:10,000 w·«•J:<9
C,)a:
U)«
0
-j J:-l u
I-enz0w
~I-
0
Zw
w ~
CJ(
0 0
w w
0 CJ(
z 1000 ~0
w W
0-0
U)Z
:::J w
U)0-
U)
:::Jen
Figure 2.--Sediment-transport curves of suspended silt-clay and sand discharge for Susitna River near
Talkeetna,May to September,1981-85.
18
0,00
ear
500,000 ,----,--..,--,--..,.-,-,-rrT---,--,--,..,-;rTlTI
b,1967-80
•1981-84o1985
Q Stream discharge
Qs+c Silt-clay discharge
Osand Sand discharge
100,000
Qs+c =1.39 x 10.7 Q2.63
10,000
1000
100
Figure 3.--Sediment-transport curves of suspended silt-clay and sand discharge for Chulitna River below
canyon near Talkeetna,May to September,1981-85.
19
Os+c =7.90 x 10-11 0 3 .18
500,000
100,000
>-«
Cl
0:
UJ
0-
en
Z
0
I-
Z
UJ 10,000
~
0:«
:I:
()en
Cl
I-
Z
UJ
~
Cl
UJ
U?
Cl 1000
UJ
Cl
Z
UJ
0-en
:::len
100
.1983-84
01985
o Stream discharge
Os+c Silt-clay discharge
Osand Sand discharge
o
Osand =4.21 x 10-7 0 2 .35
50,(I I I I I I I I I I I I I I I I I I
1000 •----------
Figure 4.--Sediment-transport curves of suspended silt-clay and sand discharge for Susitna River bel,
Chulitna River near Talkeetna (sum of right and left channels),IMay to September,1983-
20
Figure 5.--Sediment-transport curves of suspended silt-clay and sand discharge for Talkeetna River
near Talkeetna,May to September,1981-85.
•Osand =1.20 x 10-7 0 2 .65
••
•
•
•
61966-80
•1981-84o1985
o Stream discharge
Os+c Silt-elay discharge
Osand Sand discharge
Os+c=9.13x 10-10 0 3.16
100
1000
10,000
000
elo
3-8
21
1,000,000
Qsand =4.16 x 10-7 Q2.31
•
•
Qs+c =6.45 x 10-10 Q2.93
1000 !I!I ! I I I "! I I I I .I LJ ~.......
10,000 100,000 1,000,000 10,000 100,000
WATER DISCHARGE,IN CUBIC FEET PER SECOND
Figure 6.--Sediment-transport curves of suspended silt-clay and sand discharge for Susitna River at Sunshine,May to September,1981-85.
2,000,000
I
£::::,1971-80
1,000,000l-•1981-84
o 1985
Q Stream discharge
Qs+c Silt-clay discharge
Qsand Sand discharge.•>-«
Cl
0::
W
Q.
C/)
Z
0
I-
Z
w
<.9
0::«J:
C,)
C/)
Cl
N l-
N Zw
~
Clw
CIt
Cl I •w
Cl 10,000z
W
Q.
C/)
:::>
C/)
Osand =2.29 x 10.3 Q1.55
Qs+c =4.02 x 10.7 .Q2.37
o
•1981·84o1985
Q Stream discharge
Qs+c Silt·clay discharge
Qsand Sand discharge
1000,"I I I I I I I I I I I I 1.1 ...'.1
1b,000 100,000 1.000,000 10,000 100,000
WATER DISCHARGE,IN CUBIC FEET PER SECOND
1,000,000
>-«Cl
ex:wa-
U)
Zo 100,000
I-
Z
w'
<.9ex:«J:
U
U)
Cl
I-
Zw::;:
Clw
.<1(10,000
Clw
Cl
Zwa-
U)
::::>
U)
N
W
Figure 7.--Sediment-transport curves of suspended silt-clay and sand discharge for Yentna River near Susitna Station,
May to September,1981-85.
••••
Osand =3.72 x 10-401.66
Os+c =4.68 x 10-8 0 2 .46
6.1975-80
•1981-84o1985
o Stream discharge
Os+c Silt-clay discharge
Osand Sand discharge
100,000
1,000,000
>-«Cl
ex::wa..
CJ)
Z
~
Z
w·
~ex::«
::I:
U
CJ)
Cl
I-
Zw
::2:
Clw
CJ?
Clw
Cl
Zwa..
CJ)
:::>
CJ)
N
..j:>.
1,000,000
1000,"I I I I I I I I I I I I I I I I
10,000 100,000 1,000,000 10,000 100,000
WATER DISCHARGE,IN CUBIC FEET PER SECOND
Figure 8.--Sediment-transport curves of suspended silt-clay and sand discharge for Susitna River at Susitna Station,
May to September,1981-85.
x
J 1-
I
I Susitna River at Gold Creek
II OS =1.50 x 10-6 0 3 0 2 .13
i/
i-"/..I
1;1:
)(IX
/
/XX
2S
X 1952-85
f::::,1952-81]
•1982-84 (May-Sept.)
o 1985
o Stream discharge
Os Suspended-sediment discharge
\"Line of equal concentration of~suspended sediment
'\;Sustina River near Tall<~e!l1..a
Os =1.62 x 10-10 03.20
10
100,000
l ....._-1----Jl-J.--L....Ll-U.I-_-l-l-J.l-J.-1-..L..I..J..L.JL..-_...L---L--L...............a..u
100 1000 10,000 100,000
WATER DISCHARGE,IN CUBIC FEET PER SECOND
Figure 9.--Relation ()fmean suspended-sediment concentration and
discharge to Water discharge for Susitna River near Talkeetna,
May to September,1981-85 and Susitna River at Gold Creek,
October to April,1952-85..
1,000,000
>-«
Cl
0:
UJ
0-10,000
(/)z
0
I-
Z
UJ
<.9
0:«::r:u
(/)1000Cl :\"l-<$'O;)z !:>~UJ
2 ,<:5
Cl
UJ
(/)
6
UJ
Cl
Z
UJ 1000-
(/)~'v::::>
(/)<$'0;)
~~'"
X 1967-:85 (Oct.-April)
61967-:80 }
•1981·84 (May-Sept.)
01985
Q Stream discharge
Qs Suspended-sediment discharge
'I?>\'v Line of equal concentration of~suspended sediment
Os =6.99 x 10-7 Q2.51
26
1 I J I I I I I I I I I I I I I I " I '"I I I I ,I
100 1000 10,000 100,000
WATER DISCHARGE,IN CUBIC FEET PER SECOND
Figure 10.-Relation of mean suspended-sediment concentration and
discharge to water discharge for Chulitna River below
canyon near Talkeetna,1981-85.
100,000
1,000,000
>-«
Cl
0:10,000
w
Q..
(J)
Z
0I-
Z
w·~/-:.\-'-
0 ~Ol
0:
<:)/
«"::c 1000 X /u
(J)~'V
Cl ~O)/
I-~<:)/ Xz....($
w
2 /
Clw /(J)
6w /Cl 100zw ~/Q..
(J)p}f X i-
::::><:)<:)xl(J)"/1..
/1.'1.i..
~)(
X 1983 (Oct-April)
01983-84}(May-Sept.)
01985oStream discharge
Os Suspended-sediment discharge
~v Line of equal concentration of~suspended sediment
Os =8.97 x 10-9 0 2 .79
27
1
1~0::-::0:--...l..--l...-.L..L...l.~1O~O:-::O-~---l--L-L.L..l~O~,O:L:O::-::O-...l---L--L....L.JlO~O:-':,O:L!OO
WATER DISCHARGE,IN CUBIC FEET PER SECOND
Figure H.-Relation of mean suspended-sediment concentration and
discharge to water discharge for Susitna River below
Chulitna River near Talkeetna (sum of right and left
channels),May to September,1983-85.
1000
10,000
100,000
1,000,000 r:=---r--,-..,..-.,rrrnr--r-.,-.,-rrm'--TTTTTlT'=t
>-«Cl
a:::w
0...
en
Zo
I-
Z
w
~a:::«J:
()en
Cl
I-
Zw
~
Clw
CIt
Clw
Cl
Z
W
0...en:::>en
ii;"
A f::)~'
<;)<:5
~
Qs =3.04 x 10-8 Q2.87
x Yo
/
/X
/X
X /
/
X /
X 11
X ix X Qs =1.04 x 10-5 Q2.10
~
x~)(
/'~
x/xl/
ii;V
<$'
,<;)<;)<;)
1000
Figure 12.--Relation of mean suspended-sediment concentration and
discharge to water discharge for Talkeetna River near
Talkeetna,May to September,1981-85 and October to
April,1966-85.
28
1,111111111 111111111 IIIIIIIY
100 1000 10,000 100,000
WATER DISCHARGE,IN CUBIC FEET PER SECOND
X 1966-85
61966-80}
•1981-84 (May-Sept.)
01985
Q Stream discharge
Qs Suspended-sediment discharge
~~V Line of equal concentration of
100,000 t::-<;)~suspended sediment
~
1,000,000 C I I I I I I I 11 'I I I I I I I I I I I I I I I IJ
>-«
Cl
a:w
Cl..
(/)
Z
~
Z
w
<.9a:«:cu
(/)
Cl
I-
Zw
:2:
Clw
(/)
6w
Cl
Zw
Cl..-
(/)
:::>
(/)
•
Os =7.48 x 10-8 0 2 .55
~v~OJ
,,()
x
29
X 1971-85 (Oct.-April)
61971-80 ]
•19.81-84 (May-Sept.)
01985
o Stream discharge
Os Suspended-sediment discharge
,,~~Line of equal concentration of~O:>suspended sediment
/)(
/
1000 /
/
/
/
)(/
7
100 /
/
/x
X
1 0~-~-1-....l-..L-L..LL:~-=---.l..--J---I-l.-L.L.:LJ..L__--J_..L-.L...L-L.J-U.J
1000 10,000 100,000 1,000,000
WATER DISCHARGE,IN CUBIC FEET PER SECOND
Figure 13.--Relation of mean suspended-sediment concentration and
discharge to water discharge for SusitnaRiver at Sunshine,
1981-85.
10,000
10,000,000 =--.--...-rTTTrr--r---r---r'-TTlrrr--.-r-rrTl"1"1::J
1,000,000
w
<.9a:«:cuen
Cl
I-
Zw
::2:
Clw
CIt
Clw
Cl
Zwa.en:::>en
>-«
Cl
a:wa.
~100,000
o
I-
Z
Os =4.56 x 10-5 0 1.99 iiJ'v
<;::,<f::"
"
x
I
I
/
/
I
/
/
/
I Os =9.53 x 10-14 0 4 .18
/
~
X "1/X
I
)(I X
I
I
f
I
30
1 I I I I I I I I I I I I I I I I I I'I I I I I I I I I
1000 10,000 100,000 1,000,000
WATER DISCHARGE,IN CUBIC FEET PER SECOND
Figure 14.--Relation of mean suspended-sediment concentration and
discharge to water discharge for Yentna River near
Susitna Station,1981-85.
X 1981-85
.1981-84}
01985 (May-Sept.)
o Stream discharge
Os Suspended-sediment discharge
~v Line of equal concentration of J'i
\J ~O/suspended sediment 0
100,000 I="/"_/0
1,000,000 ....-----,,--....-.-.....-...,..,-,.,.--..--,.---,...--r-rr-r,,--...,---r7TTTTrCl
>-«
£:)
0::
W
Co.
en
Z
~
Z
w·
~
0::«
::I:
Uen
£:)
I-
Zw
~
£:)
w
CIt
£:)
w
£:)
Zw
Co.en::::>en
A
A
•
~
I
(#.
'/.
/
/
/
/
/
/
/
/
/
/
/
i../Os =1.30 x 10-11 0 3 .30
'f..I
l
y.x I
/1-
y.;
"1-/t
"11'1-
I
/
Os =7.66 x 10-6 0 2 .07
X 1975-85
L:::,1975-80 }
.1981-84 (May-Sept.)
01985
o Stream discharge
Os Suspended-sediment discharge
_~~Line of equal concentration of0/0)suspended sediment
10,000,000
31
100
1,000,000
Figure 15.--Relation of mean suspended-sediment concentration and
discharge to water discharge for Susitna River at Susitna
Station,May to September,1981-85 and October to April,
1975-85.
w'
~a::«:r::u
(/)
o
I-
Zw
~
ow
CQowoz
W
0-
(/)
::J
(/)
>-«o
a::w
0-
(/)
ZoI-
Z
10,000.....iii iii iii i I I I I iii iii iii iii
100,000
•
o
•
!
•
•
Ogravel =5.52 x 10-26 0 6 .14
•
y..
Osand =1.61 x 10-8 0 2 .36
X 1983-85 (Oct.-April)
.6 1981 (May-Sept.)Susitna River at Gold Creek
•1982-84}(May-Sept.)Susitna River near Talkeetna
01985o Stream discharge
Osand Sand discharge
Ogravel Gravel discharge
Osand =1.02 x 10-11
0.1
1.0
10
I
/
/
/
/
/A
/
I
0 3.10 I
/
I
I
I
I
I
'"/I
I
I
0.011 I I I I I I III III I I I I I I II I I I I I III I
100 1000 10,000 100,000 100 1000
WATER DISCHARGE,IN CUBIC FEET PER SECOND
Figure 16.--Bedload-transport curves of sand and gravel for Susitna River near Talkeetna,May to September,
w
(9
0:«J:u
(/)
Cl
Cl«g
Clw
o:l
1000
>-«100Cl
0:
Wc..
(/)
Z
~
Z
w
N
I I I I II III I I I I I I iii •i~iii iii UlO,OOO~.'u'~1111111 I I I 111"1 ~I/!I IIIII§F
y..
•
I
I
/
/
/
/
/Ogravel =1.23 x 10-14 04.22
/
/
xl<
/
/
/
/
/
/
•
Ogravel =2.6 x 10-9 0 2 .80
(Average line)
Ogravel =5.15 x 10-10 0 2 .80
(0:>29,000 ft 3/s)
/
/
/
/
></
/
/
/
/Osand =3.51 x 10-12 0 3 .63
'X /
~
/
/
/
/
"(Oct.-April),;
/(May-Sept.).,.
/
Stream discharge .f.1 W •
Osand Sand discharge ~...l
Ogravel Gravel discharge.1 ~0
/ \••T
Osand =1.2 x 10-5 0 2 .09 L~.
Osand =5.1 x 10-6 0 2 .09 \
(Average line)Q ~
Osand =3.02 x 10-7 0 2 .09
(0)29,000 ft 3/s)
10
0.1
1.0
100
0.01,"", ,"j(""I , ,II I I I I I 114 I
100 1000 10,000 100 ,000 100 1000 10,000 100 ,000
WATER DISCHARGE,IN CUBIC FEET PER SECOND
Figure 17.--Bedload-transport curves of sand and gravel for Chulitna River below canyon near Talkeetna,May to
September,1981-85 and October to April,1983-85.
1000
~«o
a:wa.
CJ)
Zo
I-
Z
w
C}
a:«::r:u
CJ)
o
o«o
..Jo
W
lXl
ww
x
o
-
I
I
I
X I
I
I
/
/Qgravel =2.59 x 10-4 Q 1.35
I
Qgravel =2.05 x 10-14 Q3.69
I
I-
I
I
/
/
~/
/
/Qsand =2.07 x 10-4 Q 1.48
X1983-85 (Oct.-April)
.1983-84 }01985 (May-Sept.),
Q Stream discharge :f:
Qsand Sand discharge -0
Qgravel Gravel discharge - _0 0
Qsand =9.16 x 10-6 Ql.78 X o-
1.0
1000
>-«
Cl
a:g:100
(J)zo
I-
Z
w'
<.9a:«
J:10u
(J)
Cl
Cl«
9
Clwco
w
,.j:l.
x
0.1
0.01 1 1 111111....11 1 II IIJ.L.U .I II L.I."11
100 1000 10,000 100,000 100 1000 10,000 100,000
WATER DISCHARGE,IN CUBIC FEET PER SECOND
Figure 18.--Bedload-transport curves of sand and gravel for Susitna River below Chulitna River near Talkeetna (sum of
_.-------------------\.--------
•
•
••
•
•
Qgravel =8.64 x 10-26 Q6.80
Qsand=2.17xlO-5 Q1.82
:(Average line)
/
/
/
/
I'l<
/O"nd •1.43 x W 12 0 3 .99
I
jx
right and left channels),1983-85.
Qsand =7.2 x 10-5
X 1983-85
.1981-84 1
01985
Q Stream discharge
Qsand Sand discharge
Qgravel Gravel discharge
0.1
0.01,'I I)\'!I III ! I I I U I J L I I I I I IIJJ
100 1000 10,000 100,000 100 ...-.1000
WATER DISCHARGE,IN CUBIC FEET PER SECOND
Figure 19.--Bedload-transport curves of sand and gravel for Talkeetna River near Talkeetna,May to September,
1981-85 and October to April,1983-85.
1000
>-«
0
0::100w
CI.
en
Z
~
Z
w'
t?
0::
W «10
VI
:cuen
0
0«0
-l
0
Wro 1.0
100,000 c=i I I I I i II iii i I I I i II Iii iii i LJ
o
Ogravel =3.11 x 10-17 0 4 .07
(Average line)
-
/-/-¥
/-
~)(/
'1./
/
~Ogravel =3.68 x 10 2 0.820
Osand =8.16 x 10-4 01.29
(Average line)
(Oct,-April)
(May-Sept.)
/
/
/
I
I
XI
Ix
)<x
/
Osand =2.45 x 10-3 01.29 -.-!\I'~1-.-,.-~
I "•
_19
o 0o
X1983-85
.1981·84 1
n1985
o Stream discharge
Osand Sand discharge
Ogravel Gravel discharge
10
100
1000
10,000
>-«
Cl
ex:wa..
en
Zo
I-
Z
w'
<!Jex:«:r:uen
Cl
Cl«o
..J
Cl
W
CXl
w
0\
'I.
0.1
x
0.01 ,I I I I I I III I I I I I IIII I I I I I III I
1000 10,000 100,000 1,000,000 1000 10,000
WATER DISCHARGE,IN CUBIC FEET PER SECOND
Figure 20.--Bedload-transport curves of sand and gravel for Susitna River at Sunshine,May to September,1981-85
•o
o
W
-...l
>-«o
ex:
LU
0-
en
Zo
f-
Z
LU
(.9
ex:«:cuen
o
o«o
..Jo
LUco
10,000
1000
100
10
1.0
X 1985 (Oct.-April)
.1984}(May-Sept)01985 .
Q Stream discharge
Qsand Sand-discharge
Qgravel Gravel discharge 0/../
.:J ~o
o I
/0
/Qsand =1.93 x 10-4 Q 1.63
/
/
/
/
/
/
/
/
)(/
/
/
)(
Qgravel =1.99 x 10-9 Q2.49
•.0'I
• I
/
;eo
I
/ 0
/
/ 0
.J
/'
/'
X ./'
./'
,-/Qgravel =0.44 QO.55
x
0.1(I I I I I I III I I I I I I III I I I I IIII t
1000 10.000 100,000 1,000,000 1000 10,000
WATER DISCHARGE,IN CUBIC FEET PER SECOND
Figure 21.--Bedload-transport curves of sand and gravel for Yentna River near Susitna Station,May to September,
1984-85 and October to April,1985.
100,000 ,.-I
X1985 (Oct.-April)
.1984 ](May-Sept.)
01985
0 Stream discharge
Osand Sand discharge
Ogravel Gravel discharge ri
10,000 \:::--0#
Osand =3.90 x 10-5 0 1.66 It'
~
I'>-/«
Cl /cr::1000 Iw
0../en
Z /0l-Iz/
w /
(9 Icr::«100 /::I:
CoN ()
/Osand =1.27 x 10-8 0 2 .4200en
Cl I
Cl 'f./«0 /...J
Cl /w
!Xl /'1.10
1.0
o
/
Ogravel =5.52 x 10-11 0 2 .69 /
-cP
oi-
/~
/
;'
/
/
/
/
/
/
/
/
/Ogravel =2.77 x 10-9 0 2 .31
l<
/
/
/
l<
0.1 "..I I I I I I III I I I I I I III I I I I III II
1000 10,000 100,000 1,000,000 1000 10,000
WATER DISCHARGE,IN CUBIC FEET PER SECOND
Figure 22.--Bedload-transport curves of sand and gravel for Susitna River at Susitna Station,1984-85 and October
SAND
GRAVEL
SANDSAND3200SAND
2400
>c(
0
a:1600w 0Q.
l/)0zfi0800I-
3:
u.i
Cl 0
a:4000c(GRAVEL::t:
0
l/)
C 3200
0
c(
0
..I
0 2400w
III
1600 0
SEPTAUGJULY
1985
JUNEMAYSEPTAUGJULY
1984
JUNEMAYSEPTAUGJULY
1983
JUNEMAY
800
o 0 ~===::=:s:=====:::;==:::=;====:=~==:::~z 60,000
u.i8
ClW
a:l/):2 ffi 40,000
OQ.
!!21-Owffi~20,000
1-0c(-==~o OL-L-__---l ----L -'-__--'
3:MAY JUNE JULY AUG SEPT
1982
EXPLANATION
o Measured bedload discharge
o Stream discharge
Osand (Sand discharge)=1.61 x 10-8 0 2 .36
Ogravel (Gravel discharge)=5.52 x 10-26 0 6 .14
Figure 23.--Variability of water and bedload discharge for Susitna River near Talkeetna,May to September,1982-85.
39
SEPTAUGJULY
1985
JUNEMAY
SAND
SEPTJULY
1984
JUNEMAYSEPTAUGJULY
1983
JUNEMAY
SAND
o
SEPTAUG
oo
JULY
1982
o
o
JUNE
o
MAYSEPT
o
AUGJULY
1981
JUNEMAY
GRAVEL
Ol-__-L .L-__--L ..l-__---l
2000
4000
2000
6000
20,000
60,00g~====::::;======::;:======::=====:::::;=====~
40,000
~o
0:
W
0.
Ul
Zo...
~
iii
Cl
0:
~0 ;::======:;::=======:;::=::;:::==;:::=:;::;::;:::=;::==~======:;o 12,000
Ul
Q
o<5 10,000
..Jo
W
IXl 8000
10,000
4000
12,000 SAND
6000
8000
oz
-0woClw
O:Ul
<0::J:w~o.-...Owo:wwu.
"'0<-:::1Xl::>o
~
EXPLANATION
o Measured bedload discharge
o Stream discharge
Osand (Sand discharge)=5.1 x 10-6 0 2 .09
Ogravel (Gravel discharge)=2.6 x 10-9 0 2.80
Figure 24.--Variability of water and bedload discharge for Chulitna River below canyon near Talkeetna,May to September,1981-85.
41
l
SEPT
a
AUGMAYJUNEJULY
1985
SAND
GRAVEL
SEPT
a
AUGJULY
1984
JUNE
a
MAYSEPTAUG
a
JULY
1983
JUNE
,SAND
L
~
~I ~~~:=;:::::=~~
1 r
l ~
MAY
'-
i
I GRAVEL
~
L
I
Ir
L
f--
l
:SAND
L
SEPTAUGJULY
1982
JUNEMAY
SAND I I I I
I-a -
a
I-a -
a
-~~~a ,,\
GRAVEL I I I
--
I
l-I -
P
I--
--
a
-
a
-
It ,.,~J2 al~,.,a a <,j>\
-
-
-
-
SEPTAUGJULY
1981
JUNEMAY
2400-
3200 I
\
ISAND
2400 --
~111600~II .A~U~800 I-~\a
0
5600 GRAVEL I I
II
I
4800 I--
I
40001-
3200
>«c
c:w
Cl.
C/)
Z
C
I-
~
ui
Clc:«:r
(.)
C/)
C
c«o
..J
C
W
£II
EXPLANATION
o Measured bedload discharge
o Stream discharge
Qsand (Sand discharge)=2.17 x 10.5 0 1.82
Ogravel (Gravel discharge)=8.64 X 10.26 0 6 .80
Figure 25.--Variability of water and bedload discharge for Talkeetna River near Talkeetna,May to September,1981-85.
43
SEPTAUGJULY
1985
JUNE
~I
MAY
SAND
GRAVEL
;
J
I
I
1
o
o
SEPTAUGJULY
1984
JUNEMAY
GRAVEL
~
I
I SAND
~
o
SEPTAUG
o
JULY
1983
oo
o
JUNE
o
MAY
SAND
SEPT
o
AUG
o
JULY
1982
MAYAUG
o
JUNEMAY
OL-__---L l-__--L --'--__--'
SEPT
2000
4000
800g~====::::;::======~:;:::;==~::;=::;::::;:===:=====~
GRAVEL
2000
>4000
<:c
a:w
Q.
CIl
Zot-
~
W
Cla::2 6000o
CIl
is
c<:o
..I
C
W
IX!
6000r-----.----.----.----,------,
SAND
160,00g:====~===~~==:;::===~==~
EXPLANATION
~140,000
oow
CIla:120,000
w
Q.
t-
W~100,000
o /.iiiB 80,000
:S-o"A AI:60,000 I~V~40,000 rv
~20,000/
o Measured bedload discharge
Q Stream discharge
Osand (Sand discharge)=8.16 x 10-4 Q 1.29
Qgravel (Gravel discharge)=3.11 x 10-17 Q4.07
Figure 26.--Variability of water and bedload discharge for Susitna River at Sunshine,May to September,1981-85.
45
Table l.--Summary of streamflow and sediment data for selected stations in the Susitna River basin
[From Still and Jones,1985 and U.S.Geological Survey,Alaska District files]
Drainage
Map No.area Period
(fiR.1)Station number Station name (square mile)Data type of record
625000149223500 Portage Creek near Gold Creek --Streamflow 1984
Suspended sediment 1984
Bedload 1984
Bed material 1984
2 624718149393600 Indian Creek near Gold Creek --Streamflow 1984
Suspended sediment 1984
Bedload 1984
Bed material 1984
T
3 15292000 Susitna River at Gold Creek 6,160 Streamflow 1949-85 ;
Suspended sediment 1952-57,1962, 1967,1974-85 ~
(Bedload 1981 .;
Fed material 1981 (
C
4 ---Susitna River at river mile 128.7 S
near Sherman Creek --Bed material 1984 "
c
..r.
5 ---Susitna River at river mile 125.6 ~
near Skull Creek --Bed material 1984 .~
p:
6 15292100 Susitna River near Talkeetna 6,320 Streamflow 1982-85 ~
Suspended sediment 1982-85 ~
-I'Bedload 1982-85 .~
Bed material 1982-85 rJ.
7 15292400 Chulitna River near Talkeetna 2,570 Streamflow 1958-77,1979-85 (l..s:
Suspended sediment 1967-72,1980-85 .;.:
Bedload 1981 .~
Bed material 1981 fL
i=
C815292410ChulitnaRiverbelowcanyon2,580 Streamflow 1982-85 +:
near Talkeetna Suspended sediment 1982-85 CIi.;.:>
Bedload 1982-85 CIJ
Bed material 1982-85 '0
(l)
.;.:>
9 15292439 and Susitna River below Chulitna 8,950 Streamflow 1983-85
Q
(l)-10 15292440 River near Talkeetna Suspended sediment 1983-85 (l)
Bedload 1983-85 en
'"'Bed material 1983-85 .s
C1$11 15292700 Talkeetna River near Talkeetna 2,006 Streamflow 1964-85 .;.:>
C1$Suspended sediment 1966-85 '0
Bedload 1981-85 ~
Bed material 1981-85 i=:
(l)
S
12 15292780 Susitna River at Sunshine 11,100 Streamflow 1981-85 .....
'0
Suspended sediment 1971,1977,1981-85 (l)
Bedload 1981-85 ~
'0Bedmaterial1981-85 (l)
'0
13 15294345 Yentna River near Susitna Station 6,180 Streamflow 1980-85 i=:
(l)
Suspended sediment 1981-85 Q,en
Bedload 1984-85 ::l
Bed material 1984-85 U?,
14 15294350 1974-85 eNSusitnaRiveratSusitnaStation19,400 Streamflow (l)
Suspended sediment 1975-85 :0
Bedload 1984-85 ~Bed material 1984-85
46
Table 2.--Suspended-sediment data for selected stations in the Susitna River basin,October 1984 to Se~tember 1985
[fts/s,cubic feet per second;DC,degrees Celsius;mg/L,milligrams per liter;ton/d,tons per day]
Sediment
Water concen-Sediment Suspended sediment
Hap No.Ststion name Date of Discharge tempera-tration discharge Percent finer than size indicated.in mil Jimeters
(fig.1)and nUDlher collection (ft'/s)ture (OC)(Dlg/L)(ton/d)0.002 0.004 0.008 0.016 0.031 0.062 0.125 0.250 0.500 1.000
3 Susitna River May 29 ----610 -------- --
33 46 58 97 100
at Gold Creek June 27 29.800 --419 33.700 3 7 --15 --35 49 74 99 100
(15292000)July 24 25.500 --435 29.900 20 27 34 42 50 58 67 83 99 100
Aug.28 14.700 --97 3.850 ---- ------69 77 89 100 --
Sept.24 14.400 --38 1.480 ---- -- ----36 47 70 98 100
6 Susitna River May 29 46.000 4.0 703 87.300 6 9 --18 --37 54 84 99 100
near June 26 30.900 9.0 251 20.900 5 8 --22 --47 62 81 100
Talkeetna July 26 21.000 12.5 310 17.600 25 29 41 50 56 62 70 88 100
(15292100)Aug.13 30.000 9.5 474 38.400 8 12 18 25 35 47 65 87 100
Sept.6 14.200 7.5 69 2.650 24 34 43 52 62 68 74 85 99 100
Sept.19 18.900 3.5 110 5.610 ---- ------43 50 78 99 100
8 Chulitna River May 31 18.000 2.0 594 28.900 12 18 25 33 43 53 64 82 97 100
below canyon June 27 22.700 6.5 1.240 76.000 19 29 40 53 71 80 91 99 100 100
near July 24 24.600 6.5 985 65,400 28 40 52 64 72 79 84 92 98 98
Talkeetna Aug.16 38.900 7.0 1,920 202,000 18 26 35 43 53 63 74 89 97 100
(15292410)Sept.5 13,800 4.5 410 15.300 22 31 41 50 57 64 69 80 96 100
Sept.17 18.200 3.0 544 26.700 16 23 30 36 42 49 58 76 99 100
Susitns River May 30 34,000 2.5 912 83.700 9 14 20 28 38 52 66 81 99 100
below Chulitna June 25 31.500 7.5 591 50,300 20 29 38 46 54 64 73 85 98 100
River (right July 25 33,700 10.5 1.120 102,000 23 33 45 55 64 73 76 84 98 100
channel)near Aug.15 39.000 7.5 3,400 358.000 9 15 22 32 45 69 85 92 98 100
Talkeetna Sept.4 26.000 8.0 365 25,600 10 19 --39 --53 60 64 93 100
(15292439)Sept.18 27 .000 3.5 388 28.300 12 17 --28 --39 45 65 96 100
...10 Susitna River May 30 24.000 3.5 554 35.900 ---- -- ----37 50 80 100
-...l below Chulitna June 25 14,400 9.0 193 7.500 7 13 --26 --40 47 74 100
River (Jeft July 25 13.600 12.0 390 14.300 22 31 41 49 58 63 72 91 100
channel)near Aug.15 25.000 10.0 508 34.300 11 16 23 33 45 58 71 93 100
Talkeetna Sept.4 9.800 10.0 126 3.330 21 29 --52 --70 77 92 100
(15292440)Sept.18 10,000 4.0 222 5,990 _.--------40 48 83 100
11 Talkeetna Jan.11 712 0.0 2 3.8
River near May 28 17.100 3.0 607 28,000 5 9 --19 --39 56 83 95 100
Talkeetna May 30 12.600 --409 13.900 ----------18 30 67 94 100
(15292700)June 26 9.320 6.0 146 3,670 ----------26 38 64 100 --
July 25 9.730 --418 11.000 14 20 27 35 42 50 60 85 99 100
Aug.15 15,900 8.5 680 29.200 11 18 25 34 43 52 63 81 96 100
Aug.29 6.800 8.5 192 3.530 ----------22 33 55 97 100
Sept.5 5,860 8.0 181 2.860 ----------19 --------
Sept.16 13,900 6.0 503 18.900 ----------34 49 81 99 100
12 Susitna River March 19 4.000 0.0 21 227 ---- ------48 65 83 100
at Sunshine May 31 66.600 3.5 560 101.000 6 9 --19 --35 52 83 99 100
(15292780)June 25 55.600 --333 50.000 15 23 32 39 48 57 65 80 100
July 23 72 .200 11.0 912 178,000 18 27 36 46 53 64 72 88 100
Aug.12 67.700 8.5 1,680 307.000 8 13 20 32 52 73 88 96 100
Sept.3 46,400 --381 47.700 16 25 33 41 49 57 66 83 99 100
Sept.16 75,700 6.5 710 145.000 11 17 23 32 42 56 73 93 99 100
Sept.24 36.800 4.0 199 19,800 6 9 --19 --34 46 78 99 100
13 Yentna R:1 ver }lay 23 23.100 5.0 494 30,800 6 9 --22 --52 76 98 100
near ~t1si tna June 20 42.800 8.5 322 37,200 ---- --
-_..-34 48 83 100
Station July 17 53,700 10.5 784 114.000 21 30 40 49 57 64 73 87 100
(15294345)Aug.14 52,600 9.0 657 93.300 17 25 --42 --61 72 90 100
Aug.19 39,800 8.0 669 71,900 20 29 38 47 55 63 73 89 100
Sept.18 22.700 4.0 355 21,800 14 19 23 26 30 35 44 72 99 100
14 Susitna Rher March 27 6.020 --4 65 ----.-_.--79
~t SUf\1tna }fay 24 65.000 4.5 958 168.000 4 6 --16 --45 65 90 100
Station June 21 95.700 9.0 272 70,300 11 17 --31 --47 58 86 100
(J 5294350)July 18 116.000 12.5 656 205,000 26 38 50 61 70 79 86 97 100
Aug.14 137.000 9.5 762 282,000 14 21 29 37 49 61 74 91 100
Aug.20 101,000 --496 135.000 20 29 39 48 57 68 80 97 100
Sept.19 85,000 4.5 306 70.200 11 15 ..-28 --46 64 94 100
Table 3.--Hydraulic and bedload data for selected stations in the Susitna River basin,October 1984 to September 1985
[ft3 /s,cubic feet per second;ft/s,feet per second;ton/d,tons per day;mm,millimeters]
Water Average Average Bedload Particle-size distribution of bed sediment
Map No.Station name Date of discharge depth Width velocity discharge Percentage.by weight.finer than size (rom)indicated
(fig.1)and number collection (ft'!s)(feet)(feet)(ft!s)(ton!d)0.062 0.125 0.25 0.50 1.0 2.0 4.0 8.0 16.0 32.0 64.0 76.0
Sus!tna River Feb.21 1,600 ------0.04 ----0 81 99 99 100
near May 29 46.400 7.8 658 9.0 590 --0 2 65 82 84 86 88 91 100
Talkeetna June 26 30.600 6.3 621 7.8 348 --0 I 72 94 95 96 98 100
(15292100)July 26 21.000 5.8 607 5.9 212 --0 1 82 99 100 ------
Aug.13 29.'tOO 6.3 622 7.5 560 --0 I 68 88 89 90 91 91 100
Sept.6 14.300 4.2 560 6.0 67 ----0 70 98 99 99 100 --
Sept.19 18.900 5.2 594 6.1 212 --0 I 75 94 95 96 96 100
8 Chulitna River Feb.27 1,200 -- ----1.1 --0 2 19 68 85 89 93 100
below canyon April 4 1,100 ------15 ----0 6 76 85 98 100 --
near May 31 18.300 7.6 340 7.0 6,010 --0 1 12 35 42 53 71 82 95 100
Talkeetna June 27 22.300 8.6 345 7.5 6.990 --0 1 15 33 37 43 50 65 83 98 100
(15292410)July 24 23.600 9.2 345 7.4 3.590 --0 I 13 31 39 46 55 71 92 100
Aug.16 39.000 11.1 395 8.9 4.670 --0 1 12 24 27 34 46 61 80 100
Sept.5 14.300 7.4 338 5.7 3.900 --0 1 20 50 66 73 79 88 97 100
Sept.17 18.200 8.2 340 6.5 6.020 --0 I 18 45 51 56 63 76 92 100
Susitna River Feb.10 1.300 ------37 --0 1 10 20 24 29 38 49 57 100
below May 30 34,000 3.7 1.100 8.4 5.530 ----0 9 18 21 25 40 67 92 100
Chulitna River June 25 31,500 4.3 810 9.1 3,610 ----0 7 11 12 15 22 40 75 100
(right July 25 33.700 5.0 940 7.2 2,740 ----0 13 34 38 43 53 71 93 100
channel)near Aug.15 39.000 3.3 1.660 7.1 2,440 --0 1 22 41 45 48 55 70 87 100
Talkeetna Sept.4 26.000 4.6 820 6.9 680 --0 1 45 79 83 86 89 92 94 100
(15292439)Sept.18 27.000 4.8 820 6.9 2.320 --0 1 25 43 46 52 59 72 96 100
10 Susttns River Feb.20 1,600 ------0.10 --0 3 58 92 99 100
below May 30 24.000 2.9 1.540 5.4 290 0 1 5 59 76 78 80 82 88 93 100
Chulitna River June 25 14.400 3.6 790 5.1 741 --0 6 80 90 90 92 92 93 96 100
(left channel)July 25 13.600 3.4 740 5.4 572 --0 2 62 78 79 80 82 86 96 100
near Aug.15 25.000 2.7 1.700 5.4 1.030 --0 2 58 74 75 76 77 80 85 100
Talkeetna Sept.4 9.800 3.2 540 5.7 135 --0 1 63 84 86 88 90 98 100 --
(15292440)Sept.18 10.000 2.8 780 4.7 371 --0 I 75 85 85 86 87 88 97 LOO
11 Talkeetna Feb.28 490 ------0
River near May 28 17.100 7.0 350 7.0 1,290 ----0 8 15 20 23 29 41 61 82 100
Talkeetna May 30 12.600 ------1,570 --0 2 25 49 53 57 65 77 93 100
(15292700)June 26 9,420 5.0 340 5.6 384 ----0 42 81 85 86 88 90 98 100
July 25 9.630 5.2 334 5.5 1.220 --0 3 48 80 84 86 88 91 97 100
Aug.15 15.800 6.6 342 7.0 1.850 --0 1 16 36 40 42 44 52 69 94 100
Aug.29 6.860 4.3 328 4.8 802 --0 I 36 89 92 95 97 99 100 --
Sept.5 5.900 3.9 327 4.6 836 ----0 34 80 89 94 96 97 99 100
Sept.16 13.800 5.8 350 6.8 1.140 -0 2 31 53 55 58 63 71 88 100
12 Susitns River Feb.26 3,500 ------81 --0 I 24 46 47 50 55 59 70 100
at Sunshine April 9 3.900 ------28 ----0 46 93 98 99 100 -----
(15292780)May 31 67.400 10.6 945 6.7 2.590 --0 3 22 30 31 34 52 72 90 100
June 25 55,600 9.1 945 6.4 2,380 --0 I 44 70 71 73 75 80 92 100
July 23 72.900 ------584 0 1 6 72 87 88 89 90 92 95 100
Aug.12 63.100 10.3 955 6.4 1.260 0 1 2 48 60 62 64 69 81 99 100
Sept.3 46,900 7.8 937 6.5 919 --0 2 52 68 70 72 76 87 97 100
Sept.16 76,500 11.0 950 7.3 1,430 --0 I 27 40 44 48 57 78 92 100
13 Yentna River Feb.28 2.600 ------31 ----0 34 55 56 67 85 100
near Susitna April 4 2.400 ------130 --0 2 30 52 61 69 82 96 100
Station May 23 23.300 6.8 1.275 2.7 5.720 0 I 14 66 82 85 86 88 94 99 100
(15294345)June 20 42.600 8.5 1.280 3.9 6,130 --0 3 70 91 94 96 98 99 100
July 17 54.200 9.4 1.290 4.5 8.070 --0 3 60 90 93 95 98 99 100
Aug.14 52.800 8.7 1.290 4.7 13.300 --0 2 47 84 88 92 96 99 100
Aug.19 39.700 7.7 1,285 4.0 4,360 --0 3 57 92 96 97 99 100
Sept.18 22.600 5.5 1.285 3.2 7,490 --0 2 47 84 91 95 98 100
14 Susltna River Feb.28 6.500 ------15 --0 3 71 79 79 82 89 100
at Susitna April 4 6,500 -----30 --0 I 77 99 99 100 ----
Station May 24 64,900 8.1 1,670 4.8 4,690 0 1 6 65 81 82 82 85 90 97 100
(15294350)June 21 94.500 13.5 1,880 3.7 9,240 --0 4 65 90 93 95 96 98 100 --
July 18 117,000 12.2 1.880 5.1 11,200 --0 3 62 84 86 89 92 95 99 100
Aug.14 138.000 14.3 1.880 5.1 20.900 --0 2 34 57 62 68 76 85 94 100
Aug.20 102.000 10.8 1,870 5.0 10,100 0 I 8 63 81 86 89 91 94 98 100
Sept.19 85.000 9.7 1,880 4.6 9,820 0 1 7 53 86 91 94 96 99 100
48
Table 4.--Bed-material data for selected stations in the Susitna River basin,May!to September 1985
(Sampling point stationing from left bank)
Bed material
Hap No ..Station name Date of Sampling Percent finer than size indicated,in millimeter
(fig.1)and number collection point Sample type 0.062 0.125 0.25 0.50 1.0 2.0 4.0 8.0 16.0 32.0 64.0 128.0
Susttna River May 31 60a dredged
near Talkeetna 160a dredged
(15292100)260b dredged 0 9 17 39 100
360b dredged 0 I 4 100
460c dredged 0 100
560c dredged 0 2 100
Chull tna River May 31 50a dredged
below canyon 100b dredged 0 I 1 13 36 62 90 100
near Talkeetna 150b dredged 0 2 1I 14 18 3&45 69 100
(15292410)200b dredged 0 I 2 II 33 67 89 98 100
250b dredged 0 I 1 4 6 6 9 66 100
Susitns River May 30 3700bd dredged 0 I 2 6 12 42 100
below Chul i tna 3800bd dredged 0 I 2 4 II 47 100
River (right 3900bd dredged 6 10 23 47 85 95 100
channel)near
Talkeetna
(15292439)
10 Sus1tns River May 30 700bd dredged 0 4 4 16 71 100
below Chuli tna 800bd dredged 0 29 100
River (left 900cd dredged 0 I I 100
channel)
near Talkeetna June 26 1I00bd surface 0 I I I I I I 2 9 32 100
(15292440)1I00bd suh-sur 2 4 6 12 18 22 27 34 47 68 88 100
1300bd surface I 2 4 5 5 5 6 7 27 68 100
1300bd suh-sur I 4 8 19 26 30 35 48 69 96 100
1500bd surface,Bub-sur 0 2 15 83 100
J700bd surface 0 I 2 2 3 3 3 3 6 39 86 100
1700bd sub-sur 2 5 II 18 22 22 24 29 47 73 97 100
1900bd surface I 2 3 4 4 4 4 4 7 27 79 100
1900bd sub-sur 2 4 8 15 27 28 34 45 61 80 100
2100bd surface,sub-sur 9 27 79 98 100
2380bd surface.sub-sur 45 92 99 100
2560bd surface I 2 3 3 3 3 4 4 19 100
2560bd sub-sur 2 4 9 14 16 18 22 29 41 58 89 100
2770bd surface 0 I I I I I 5 29 78 100
2770bd sub-sur il 14 18 20 24 35 50 76 88 100
-"~~--_._-----_._,,_.-
II Talkeetna River May 28 50a dredged
near Talkeetna 100b dredged 0 7 22 100
(15292700)150c dredged 0 I 100
200b dredged 0 6 26 100
250b dredged 0 2 21 100
300c dredged 0 100
12 Sus1 tna River July 23 200c dredged 0 100
at Sunshine 300b dredged 0 II 100
(15292780)400b dredged 0 2 3 9 39 100
500b dredged 0 I 3 27 100
600b dredged 0 4 4 8 100
700b dredged 0 8
800b dredged II 52 97 99 99 100
900b dredged 0 13 57 96 96 97 97 97 100
13 Yentna River Aug.14 200b dredged-0 2 38 88 80 94 94 99 100
near Susitna 400b dredged 0 5 64 90 92 93 95 98 100
Station 600b dredged 0 6 65 92 95 96 97 99 100
(15294345)800b dredged 0 4 51 93 93 94 96 98 100
1000b dredged 0 3 40 60 62 64 66 70 78 100
14 Susitna River Aug.14 80a dredged
at Susi tna 280b dredged 0 6 60 76 78 82 88 95 97 100
Station 480b dredged 0 I 5 8 8 8 9 14 18 100
(15294350)680b dredged 0 3 55 72 75 78 81 85 95 100
880b dredged 0 I 17 47 62 70 76 89 100
1080b dredged 0 2 39 66 70 72 75 82 91 100
1280b dredged 0 3 41 72 73 76 82 92 100
1480b dredged 0 6 79 91 93 94 96 99 100
1680b dredged 0 I 27 87 95 96 98 99 100
a Streambed too coarse to obtain samples
b Representative sample obtained for particles finer rhan 128 mm
c Few particles obtained;non-representative sample
d Stationing from left bank at Susitna River.lefc channel (15292440)
49
"'~'""""~~~"'-"-~"~"~-~"~-"""""-~~-~"="-="==="=~~-~~----------------
Table 5.--Water discharge and estimated sediment loads at selected stations in the Susitna River basin,
October 1984 to September 1985 [mi2 ,square miles;acre-ft,acre-feet]
Drainage Water
Map No.Station name area discharge Suspended sediment (tons)Bedload (tons)Total sediment
(fig.I)and number (mi')Period (acre-ft)Silt-clav Sand Total Sand Gravel Total (tons)
Sus1tna River 6.320 October 349.000a 4,500 1,700 6,200 160 0.4 160 6,360
near November 186,OOOa ----1,300 25 0 25 1,320
Talkeetna December 149,OOOa ----750 10 0 10 760
(15292100)January 132,OOOa -- --
580 7.0 0 7.0 587
February 96,800a ----330 3.8 0 3.8 334
March 116,OOOa ----440 4.2 0 4.2 444
April 129,OOOa ----590 8.7 0 8.7 599
May 811,OOOa 350,000 330,000 680,000 7,500 5,100 12,600 693,000
June 1,710,OOOa 530,000 420,000 950,000 17,000 5,500 22,500 972,000
July 1,710,OOOa 540,000 440,000 980,000 16,000 6,500 22,500 1,000,000
August 1,330,OOOa 240,000 160,000 400,000 8,800 1,100 9,900 410,000
September 1,020,OOOa 130,000 77 ,000 207,000 4,700 400 5,100 212,000
October 1,160,000 ----9,290 219 .4 219 10,400
to April
May 6,580,000 1,790,000 1,430,000 3,220,000 54,000 18,600 72,600 3,290,000
to
September
Total 6,720,000 ----3,230,000 54,200 18,600 72,800 3,300,000
8 Chulitna River 2,580 October 290,600 23,000 18,000 41,000 3,300 2,000 5,300 46,300
below canyon November 159,100 ----8,900 300 110 410 9,310
near Talkeetna December '132,900 ----5,100 140 46 186 5,290
(15292410)January 117,000 ----3,800 89 26 115 3,920
February 77 ,550 ----1,600 26 6.8 33 1,630
March 71,600 ----1,100 14 3.1 17 1,120
April 67,240 ----980 13 3.1 16 996
May 351,300 170,000 96,000 266,000 30,000 17,000 47,000 313,000
June 1,125,000 770,000 430,000 1,200,000 140,000 77 ,000 217,000 1,420,000
July 1,669,000 2,100,000 1,100,000 3,200,000 180,000 140,000 320,000 3,520,000
August 1,278,000 1,100,000 600,000 1,700,000 140,000 90,000 230,000 1,930,000
September 782,700 320,000 200,000 520,000 66,000 31,000 97,000 617,000
October 916,000 ----62,500 3,880 2,200 6,080 68,600
to April
May to 5,206,000 4,460,000 2,430,000 6,890,000 556,000 355,000 911,000 7,800,000
September
917 ,000Total6,122,000 ---6,950,000 560,000 357,000 7,870,000
Susitna Ri.ver 8,950 October 624,OOOb ----60,OOOb 5,600 2,100 7,700 67,700
below Chulitna November 303,OOOb ----9,OOOb 1,900 780 2,680 11,700
10 River near December 245,OOOb ----5,OOOb 1,400 580 1,980 6,980
Talkeetna January 237,OOOb ----4,OOOb 1,300 560 1,860 5,860
(15292439 and February 182,OOOb ----3,OOOb 920 400 1,320 4,320
15292440)March 200,OOOb ----3,OOOb 1,000 440 1,440 4,440
April 212,OOOb ----3,OOOb 1,100 490 1,490 4,490
June 3,OOO,OOOb 2,300,000 1,500,000 3,800,000 63,000 140,000 203,000 4,000,000
July 3,500,OOOb 3,700,000 2,100,000 5,800,000 73,000 170,000 243,000 6,040,000
August 2,760,OOOb 1,800,000 1,200,000 3,000,000 54,000 110,000 164,000 3,160,000
September 1,920,OOOb 660,000 560,000 1,220,000 30,000 37,000 67,000 1,290,000
October 2,OOO,OOOb ----87,OOOb 13,200 5,350 18,500 105,000
to April
May to 12,500,OOOb 9,370,000 5,900,000 15,300,000 243,000 500,000 743,000 16,000,000
September
Total 14,500,OOOb ----15,400,000 256,000 505,000 761,000 16,100,000
11 Talkeetna 2,006 October 135,100 1,400 3,000 4,400 780 0.3 780 5,180
River near November 68,930 ----860 78 0 78 938
Talkeetna December 55,140 ----520 28 0 28 548
(15292700)January 44,070 ----320 12 0 12 332
February 30,410 ----170 3.8 0 3.8 174
March 30,600 ---150 3.1 0 3.1 153
April 31,060 ----160 3.3 0 3.3 163
May 256,700 84,000 85,000 169,000 4,800 8,700 13,500 182,000
June 618,800 170,000 190,000 360,000 12,000 11,000 23,000 383,000
July 684,900 240,000 240,000 480,000 13,000 16,000 29,000 590,000
August 626,200 200,000 200,000 400,000 13,000 13,000 26,000 426,000
September 501,300 120,000 130,000 250,000 8,700 5,600 14,300 264,000
October to 395,300 ----6,580 908 0.3 908 7,490
April
May to 2,688,000 814,000 845,000 1,660,000 51,500 54,300 106,000 1,760,000
September
Total 3,083,000 ----1,670,000 52,400 54,300 107,000 1,770,000
12 Sus!tna River 11,100 October 759,500 24,000 41,000 65,000 4,900 2,600 7,500 72,000
at Sunshine November 372,000 ----10,000 1,900 1,400 3,300 13,300
(15292780)December 299,900 ----5,600 1,500 1,200 2,700 8,300
January 280,700 ----4,700 1,300 1,100 2,400 7,100
February 212,200 ----2,800 900 890 1,790 4,590
March 230,500 ----2,900 1,000 980 1,980 4,880
April 243,200 ----3,500 1,100 970 2,070 5,570
~ay 1,583,000 870,000 560,000 1,430,000 15,000 17,000 32,000 1,460,000
June 3,622,000 2,200,000 1,500,000 3,700,000 37,000 33,000 70,000 3,770,000
July 4,183,000 3,300,000 2,000,000 5,300,000 44,000 59,000 103,000 5,400,000
August 3,384,000 1,800,000 1,200,000 3,000,000 33,000 26,000 59,000 3,060,000
September 2,425,000 770,000 620,000 1,390,000 22,000 11,000 33,000 1,420,000
October 2,399,000 ----94,500 12,600 9,140 21,700 116,000
to April
May to 15,200,000 8,940,000 5,880,000 14,800,000 151,000 146,000 297,000 15,100,000
September
Total 17,600,000 ---14,900,000 164,000 155,000 319,000 15,200,000,
50
Table 5.--Water discharge and estimated sediment loads at selected stations in the Susitna River basin,
October 1984 to September 1985 --Continued
Drainage Water
Map No.Station name area discharge Suspended sediment (tons)Bedload (tons)Total sediment
(fig.1)and number (mi')Period (acre-ft)Silt-clay Sand Total Sand Gravel Total (tons)
13 Ycntna River 6,180 October 843,600 110,000 190,000 300,000 36,000 3,000 39,000 339,000
near Sus!tna November 260,200 5,800 4,100 1,300 5,400 11,200
Station December 185,300 1,200 2,100 1,100 3,200 4,400
(15294345)January 182,100 970 2,000 1,100 3,100 4,070
February 158,300 760 1,700 980 2,680 3,440
March 161,100 580 1,600 1,000 2,600 3,180
April 148,800 460 1,500 980 2,480 2,940
May 1,186,000 460,000 410,000 870,000 82,000 8,900 90,900 961,000
June 2,886,000 1,600,000 1,300,000 2,900,000 250,000 29,000 279,000 3,180,000
July 3,613,000 2,600,000 1,800,000 4,400,000 360,000 48,000 408,000 4,810,000
August 2,841,000 1,500,000 1,200,000 2,700,000 240,000 27,000 267,000 2,970,000
September 1,775,000 560,000 620,000 1,180,000 120,000 9,800 130,000 1,310,000
October 1,939,000 310,000 49,000 9,460 58,500 368,000
to April
May to 12,300,000 6,720,000 5,330,000 12,000,000 1,050,000 123,000 1,170,000 13,200,000
September
Total 14,240,000 12,400,000 1,000,000 132,000 1,230,000 13,600,000
14 SusitDa River 19,400 October 1,892,000 160,000 250,000 410,000 33,000 2,800 35,800 446,000
at Susitna November 651,600 9,000 2,400 180 2,580 11,600
Station December 505,800 3,400 1,200 96 1,300 4,700
(15294350)January 489,900 3,000 1,100 89 1,190 4,190
February 385,800 1,800 710 59 769 2,570
March 399,700 1,600 650 56 706 2,310
April 405,600 1,800 720 60 780 2,580
May 2,808,000 1,200,000 880,000 2,080,000 95,000 20,000 115,000 2,200,000
June 6,706,000 3,900,000 2,700,000 6,600,000 290,000 67,000 357,000 6,960,000
July 8,281,000 6,300,000 3,800,000 10,100,000 400,000 110,000 510,000 10,600,000
August 6,686,000 3,700,000 2,700,000 6,~00,OOO 280,000 64,000 344,000 6,740,000
September 5,005,000 1,900,000 1,700,000 3,600,000 180,000 31,000 211,000 3,810,000
October 4,730,000 431,000 39,800 3,340 43,100 474,000
to April
May to 29,490,000 17,000,000 11,800,000 28,800,000 1,240,000 292,000 1,540,000 30,300,000
September
Total 34,220,000 29,200,000 1,280,000 295,000 1,580,000 30,800,000
a Estimated
b Difference between Susitna River at Sunshine and Talkeetna River near Talkeetna
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