A GEOTECHNICAL INVESTIGATION OF THE PROPOSED …akenergyinventory.org/hyd/SSH-1984-0112.pdf · A GEOTECHNICAL INVESTIGATION OF THE PROPOSED ... gation of the Proposed King Cove Hydroelectric

Ala.ka Energy Authority LIM'" COP!'

A GEOTECHNICAL INVESTIGATION OF THE PROPOSED

KING COVE HYDROELECTRIC WEIR SITE

ON DELTA CREEK, ALASKA

Alaska Department of Nat~ral Resources Division of Geological & Geophysical Surveys

(Ori inal Report)

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D~PARTMENTOFNArURALRESOUR~ES

DIVISION OF GEOLOGICAL & GEOPHYSICAL SURVEYS

17 October 1984

Brent Petrie Alaska Power Authority 334 W. 5th Avenue Anchorage, AK 99501

Dear Mr. Petrie:

BILL SHEFFIELD, GOVERNOR

o POUCH 1·028 ANCHORAGE, ALASKA 99510 PHONE: (901) 276-2653

o 794 UNIVERSITY AVENUE, BASEMENT FAIRBANKS, ALASKA 99701 PHONE: (901) 474·7147

* P.O. Box 772116 Eagle River, Alaska 99577

Phone: (907) 688-3555

.Attached herewith please find the final rep'ort entitled "A Geotechnical Investi­gation of the Proposed King Cove Hydroelectric Weir Site on Delta Creek, Alaska" by J.W. Reeder, K.J. Krause, and R.D. Allely. This report summarizes data and conclusions of an investigation executed by the Engineering Geology Section, A18$ka Division of Geological and Geophysical Surveys, under a Reimbursable Services Agreement with Alaska Power Authority (08-73-4-490-389).

I trust that you will find that the report provides the data specified in our original agreement including:

1. Seismic refraction survey, three lines. 2. Subsurface exploration. 3. iO-component peizometer array installation. 4. Boulder distribution assessment. 5. Stream discharge variance study. 6. Indentification of material resources. 7. Ground-water flow net modeling.

In addition, the project team has been able to make some evaluations of down­stream transport of suspended and bed load sediments of the creek, is providing a description of the regional geology and potential hazards to the site, and offers suggestions of an alternative weir site.

It was a pleasure executing this work for Alaska Power Authority and we hope that our final report will be helpful in accomplishing design and construction of the facility. If we can be of any further assistance on this or other APA projects, please feel free to contact me.

l' Sincerely yours,

7-~....u k,~~ ~~. Randall G. Updike ---Chief, Engineering Geology Section

RGU/jlw

cc: D. Denig-Chakroff R. Loeffler

A GEOTECHNICAL INVESTIGATION OF THE PROPOSED

KING COVE HYDROELECTRIC WEIR SITE ON

DELTA CREEK, ALASKA

Final Report to the State of Alaska Power Authority Department of Commerce and Economic Development

334 West 5th Avenue Anchorage, Alaska 99501

under RSA 08-73-4-490-389

by

J.W. Reeder, K.J. Krause, and R.D. Allely Alaska Division of Geological and Geophysical Surveys

September 1984

This document has not received official DGGS review and publication status, and should not be quoted as such.

State of Alaska Department of Natural Resources

Division of Geological and Geophysical Surveys P.O. Box 772116

Eagle River, Alaska 99577

TABLE OF CONTENTS

I. Introduction A. Purpose of Investigation B. Location of Study Area C. Physiography D. Acknowledgements E. Scope of Work and Methods of Investigation

II. Geologic Overview

III. Unconsolidated (Surficial) Deposits

IV. Seismic Refraction Surveys

V. Hydrology A. Surface Water and Sediment Transport B. Ground Water

VI. Potential Rock Sources

VII. Conclusions and Recommendations

References

Appendix

Page # 1 1 1 3 4 4

8

17

22

27 27 39

57

58

61

63

Figure 1. 2. 3. 4. 5. 6. 7. 8. 9.

10. 11. 12. 13. 14. 15. 16. 17. 18. 19.

20. 21. 22. 23. 24. 25. 26. 27. 28.

Plate 1. Plate 2. Plate 3.

List of Figures

Location map of study area Photo of Mount Dutton and study area Photo of King Cove and glacial valley Photo of Delta Creek valley near proposed weir site Photo of coulees near proposed weir site Photo of Clear Water Tributary and bank slump Map showing Quaternary landslides and photo lineaments Photo of Delta Creek alluvium exposed in CAT trench Particle size distribution curve for alluvium, till, and suspended sediment Photo of CAT trenching alluvium Photo of John Reeder sampling till Seismic refraction profile for 550-foot line Seismic refraction profile for 1100-foot line Seismic refraction profile for 55-foot line 1982 discharge hdyrograph for Russell Creek Photo of Delta Creek high water flow Photo of Delta Creek before storm Photo of Delta Creek after storm Graph showing affect of depth to mean velocity and discharge of bed material Photo of painted red stripe across Delta Creek Close up photo of painted red stripe Slug test for piezometer no. 10 Slug tests for piezometers 1,2,3,4,5,6,7, and 9 Curves for seepage volumes beneath weir structures Flow net for 7.5 foot deep sheet-pile weir Flow net for 15 foot wide concete-apron weir Graph showing maximum exit gradients for weirs Photo of alternate DGGS site on Clear Water Tributary

Plates located in back pocket

Aerial photo enlargement of Delta Creek Study area

Page # 2 9

11 12 13 15 16 18

19 20 21 24 25 26 28 30 32 33

36 40 41 43 44 50 52 54 56 59

Map showing seismic refraction lines and piezometer locations Map showing ground-water gradient in relation to piezometer locations

INTRODUCTION

Purpose of Investigation

In August of 1984, Alaska Power Authority (APA) approached the

Engineering Geology Section of the Division of Geological and Geophysical

Surveys (DGGS - Alaska Department of Natural Resources) concerning collection

of additional geotechnical data that were needed for the proposed King Cove

hydroelectric facility on Delta Creek. APA was ready to finalize the design

criteria for the King Cove hydroelectric facility; however, several

geotechnical issues needed to be addressed before they felt this could be

properly done. The two primary geotechnical issues of APA concern were:

depth-to-bedrock beneath the proposed diversion weir site, and the expected

ground-water seepage flow through the unconsolidated deposits under the

proposed weir. Because the above geotechnical issues were within the

capabilities of DGGS, the Engineering Geology Section (EGS) was contracted to

do the geotechnical work. In addition, EGS proposed to study and classify

the unconsolidated deposits, measure stream discharge at several sites along

Delta Creek, and identify bedrock quarry sources that could be used for

construction. In the process of doing the geotechnical investigations, EGS

identified two other concerns that are also addressed in this report. These

additional concerns are (1) local landslide and potential fault hazards, and

(2) sediment problems due to suspended sediment and bedload transport.

Location of the Study Area

The study area is located approximately six miles north of King Cove

(fig. 1). King Cove is a fishing community located on the Pacific Ocean side

of the Alaska Peninsula approximately 19 miles southeast of Cold Bay

(abandoned Fort Randall), Alaska.

-Deer P

30' Scale 1-=4 miles

Figure 1. Location map of the Delta Creek study area.

-2-

Phys i ography

The proposed hydroelectric site is located in the glaciated and eroded

Alaska-Aleutian Range physiographic province at the southwestern tip of the

Alaska Peninsula. The proposed site is located on Delta Creek, which drains

the southwest flank of Mount Dutton, a 4,884 foot high, glaciated Quaternary

volcano (fig. 1).

The Mount Emmons-Pavlof volcano region is located 10 miles northeast of

Mount Dutton. Frosty Peak is located 20 miles west of Mount Dutton. Mount

Dutton, Mount Emmons, Pavlof volcano, and Frosty Peak are all Quaternary

stratovolcanoes. Both Pavlof and Pavlof Sister of the Mount Emmons-Pavlof

volcano region have been active within historic times (Coats, 1950).

Over 40 inches of rainfall occur in the Delta Creek area per year. At

least fifty inches of average snowfall usually contribute to this

precipitation (Selkregg, 1974-77). Storms are a frequent occurrence in the

Alaska-Aleutian Range province. They can occur any time of the year and are

usually due to the passage of east-moving Aleutian lows. The climate is

maritime with an approximate mean annual temperature of 38°F. Mean annual

maximum and minimum temperatures vary less than 10°F (Waldron, 1981).

The dominant winds, which also bring the wettest weather, are from the

south-southeast. Winds from the Bering Sea usually bring colder and dryer

weather, which is more frequent during February and March. August is usually

the foggiest month; although it is not unusual for fog to occur throughout

the year. In general, the Aleutians are notorious for unpredictable weather,

and "bad" weather can occur anytime of the year.

-3-

The rich marine life of the Alaska Peninsula and Aleutian Islands has

supported mankind for at least 8,000 years (Black, 1976). King Cove was

founded in 1911 as a Pacific American Fisheries Cannery (Biery, 1966).

Fishing is still the main economic backbone for the community. On land, the

sea bird and other animal life is plentiful. Large brown bears are the most

ominous of the animal life, and are quite numerous in the province.

Trees are sparse in the province; however, tundra, alder and willow grow

on lower slopes and usually blanket lowland areas. Grasses, mosses,

flowering plants, and berry bushes are the dominant tundra vegetation.

Acknowledgements

This project was made possible through a Reimbursable Services Agreement

between APA and DGGS. We would like to thank Brent Petrie, David

Denig-Chakroff, Robert Loeffler, and Remy Williams of APA for their input

into the investigation and the assistance given in logistical planning. We

would also like to thank the City of King Cove and the King Cove Native

Corporation for their interest and logistical support of the field work.

Special thanks goes to Chester Wilson, our CAT operator, who transported our

equipment between the weir site and King Cove using the city's CAT.

Chester's operating ability also enabled us to install the piezometers which

was considered a doubtful task in our proposal. Special thanks also goes to

Jenny Weir, our typist-editor, for assisting with the report preparation.

Scope of work and methods of investigation

Geotechnical field investigations were conducted between August 20-26,

1984. Travel time required to go to King Cove and return to Anchorage was

-4-

three days. A storm during the week of field work caused Delta Creek to rise

and overflow its banks for approximately 24 hours, precluding any field work

during that period. During the three remaining days, the proposed objectives

described below were accomplished.

APA was concerned about two main geotechnical issues involving the King

Cove hydroelectric project. As mentioned earlier, these issues were

depth-to-bedrock beneath the proposed weir site, and groundwater seepage flow

within the unconsolidated sediments beneath the proposed weir. APA also

expressed concern about the erosion and sedimentation stability of the Delta

Creek channel.

The Engineering Geology Section proposed the following scope of work.

The depth-to-bedrock information would be acquired by employing standard

seismic refraction survey methods. A I2-channel signal-enhancement

seismograph and 55-foot, 550-foot, and 1,100-foot geophone lines were used.

Explosives designed for use in seismic exploration were used as energy

sources for the two longer lines. The depth-to-bedrock and thickness of the

glacial till and alluvium overlying the bedrock were determined.

It was also proposed that an excavation pit be dug and accurately logged

and sampled. It was not possible to get a backhoe to the site, so the

proposed pit investigation was done with the CAT. The CAT was able to trench

into the alluvium to the top of the glacial till. A I50-pound representative

alluvium sample and a I50-pound representative glacial till sample were

collected from the trenches. The samples were mechanically analyzed for

-5-

particle size distributions by the Department of Transportation and Public

Facilities (DOTPF) lab.

An array of 10 well-point piezometers at pre-selected locations were

installed below the water table. The CAT trenched to the water table. then

the piezometer screens were driven below the water table with the aid of a

steel fabricated driver-hammer tool. Piezometer elevations and locations

were surveyed after all were installed. The gradient for the water table was

determined from the water levels in the piezometer. Slug tests were

successfully used for determining hydraulic conductivity values on 9 of the

piezometers. Ground-water flow nets were constructed for the unconsolidated

deposits underneath the proposed weir structures in order to determine

seepage losses.

Boulder distr-ibutions were photographically documented as trenches were

dug for piezometer installations. Stream discharge measurements were also

proposed and were successfully completed at the powerhouse site and proposed

weir site. Surface-water loss was determined from the discharge measurements

for the portion of Delta Creek between the weir site and powerhouse site. In

addition to the discharge measurements. a suspended sediment sample was

collected from the stream at the weir site. The ratio of suspended sediment

to discharge was then calculated. Above the weir site. a I-foot-wide channel

cross-section strip of alluvium was painted bright red. Survey stakes with

flagging were also installed along the painted strip. The painted strip of

alluvium was photographed so that approximate erosion and/or deposition of

bed-load can be measured in the future.

-6-

Investigation for competent bedrock that could be used for backfill

ballast revealed that the best source would be from a rock quarry between

King Cove and the airport.

-7-

GEOLOGIC OVERVIEW

The region around Mount Dutton consists dominantly of well-bedded

tuffaceous sandstones and conglomerates. These were originally mapped as the

Belkofski Tuff which is prevalent in the Belkofski Bay area (Kennedy and

Waldron, 1955). The Belkofski Tuff is thought to be late Eocene or early

Miocene in age (Waldron, 1961). On the southern flank of Mount Dutton at the

1,500 foot elevation (fig. 2), the Belkofski Tuff strikes N to NE and dips

about 12 degrees south. Approximately 2-3 miles south of the weir site, the

Belkofski Tuff strikes N to NE and dips about 14 degrees south. Belkofski

Tuff beds exposed along Delta Creek also dip to the south.

North of King Cove, the Belkofski Tuff is intruded by a quartz diorite

porphry. The contact between the quartz diorite and Be"lkofski Tuff has never

been mapped, so the size of the intrusive is not known. Kennedy and Waldron

(1955) recognized this intrusive and another intrusive on the east flank of

Mount Dutton. The Belkofski Tuff appears to be highly altered in the Delta

Creek canyon above the weir site. The alteration could be a result of nearby

intrusive activity. No plutonic (intrusive) clast were seen in the alluvium

along Delta Creek, suggesting that the intrusive is not yet exposed on the

southern flank of Mount Dutton. Waldron (1961) assigned a middle-upper

Tertiary age to these intrusives.

West of the weir site, the Be"lkofski Tuff has been unconformably capped

by massive andesitic lava flows. These flows form the ridge shown on the

right in figure 2. The lava flows have not been dated but they are probably

late Pliocene or Quaternary in age. The lava flows may have come from Mount

Dutton or the Emmons Lake-Pavlof volcano region to the northeast.

-8-

Figure 2. Looking north from the airport towards Mount Dutton and the Delta Creek study area. Note the d«rk basaltic flows on the upper flanks of Mount Dutton that dip away from the sunma area of this Quaternary volcano.

-9-

The upper flanks of Mount Dutton consist of thinly layered basaltic lava

flows. These flows dip away from the summit and are exposed on the north and

northeastern flanks in the summit region. In figure 2, the volcanic flow

units can be seen dipping as steeply as 33 degrees on the upper eastern flank

of the mountain. The Mount Dutton region has never been mapped by the U.S.

Geological Survey (Kennedy and Waldron, 1955; and Waldron, 1961). Coats

(1950) claims that Mount Dutton is not a volcano. Based on our observations,

it appears that the basaltic lava flows originated from Quaternary Mount

Dutton eruptions.

Most of the unconsolidated deposits in the region consist of glacial

drift. The valley between King Cove and the airport is a classic U-shaped

glacially-carved valley {fig. 3}. King Cove itself is situated on a gravel

spit that formed across a fiord. Dense, well-compacted glacial till

underlies the alluvium in Delta Creek and forms the benches bordering Delta

Creek near the proposed weir site. The bench on the south side of Delta

Creek contains scabland-type topography which resulted from meandering

glacial outwash streams. The glacial till and outwash are deposits remaining

from middle to late Pleistocene glaciations occurring on Mount Dutton.

I~umerous abandoned stream channels (coulees) are present in the vicinity of

the proposed weir site (plate 1). Delta Creek previously occupied these

coulees (figs. 4 and 5) prior to entrenching itself to its present position.

Delta Creek, in the past, flowed where the Clear Water Tributary now exists.

Soil solifluction is an active process in this region. Solifluction is

more pronounced on vegetation-free slopes, and is visible in the photographs

as patterned ground. Talus fans occupy lower slopes west of the weir site.

-10-

t, "'"T' ; - .'~. . ..:.

Figure 3. Looking south-southwest towards King Cove which is located on a gravel spit. Note the U-shaped, glacially-carved valley in the foreground.

-11-

Figure 4. site.

Looking north-northwest up Delta Creek from near the proposed weir Note Quaternary landslide and coulees.

-12-

Figure 5. Close-up view of the coulees located above proposed weir site.

A small slump has occurred after 1980 on the east bank of the Clear

Water Tributary just above its confluence with Delta Creek (fig. 6 and plate

1). Two large landslides west of Delta Creek are shown on plate 1 and figure

7. The landslide below the weir site and on the slope above the powerhouse

site appears to be stable. This landslide did not move below the 450 foot

contour (fig. 7 and plate 1). The second landslide is located upstream above

the proposed weir site (fig. 4). Delta Creek is cutting into the toe of this

slide, thus it may not be stable. If this landslide failed again it could

temporarily dam the Delta Creek channel. No other landslides or small

bank-slumps have been recognized in the study area.

Two prominent air photo lineaments were recognized crossing Delta Creek

(figure 7 and plate 1). One is in the vicinity of the proposed powerhouse,

the other is near the proposed weir site. These lineaments trend N 41°W and

N 45°W respectively. The direction of maximum horizontal compression in

this region is N 40oW. This compression is from the Pacific Plate

underthrusting the Aleutian Arc (Nakamura et al, 1977). Southwest of this

region, on Unalaska Island, numerous small Holocene faults also strike in the

direction of maximum horizontal compression (Reeder, 1984). The Delta Creek

lineaments are traceable across both bedrock and Quaternary glacial deposits.

Therefore, these lineaments are thought to be Holocene faults. The

lineaments trend across the two large landslides and may have been

responsible for triggering these failures. Since these lineaments may

represent small Holocene faults, they probably would not generate large

earthquakes.

-14-

Figure 6. View of recent bank slump east of Clear Water Tributary. This view is just upstream from the Delta Creek confluence. Piezometer no. 1 is shown in foreground.

-15-

-16-

~ Quaternary Landslide

\ Air Photo Lineament/Possible \, Quaternary Fault

'\

Scale 1-=1 mile

Figure 7. Map showing locations of Quaternary landslides and photo­lineaments (possible faults) in relation to study areas as outlined.

UNCONSOLIDATED (SURFICIAL) DEPOSITS

Stream alluvium overlies glacial till along Delta Creek in the vicinity

of the proposed weir site. The glacial benches bordering Delta Creek near

the weir site consist of till with a thin mantle of overlying colluvium.

Figure 8 shows a CAT trench wall in the alluvium near piezometer no. 8 (plate

2). The alluvium was approximately 6-8 feet thick near piezometer no. 8. As

shown in figure 8, the alluvium is poorly sorted and poorly stratified, and

consists of boulders, gravel, sand, and silt. A 150-pound alluvium sample

was collected above the water table in a CAT trench near piezometer no. 6

(plate 2). Material analyses were performed on the sample and the cumulative

probab-ility plot for the particle size distributions is shown in figure 9.

The material analyses revealed that the alluvium consisted mainly of boulders

and gravel with about 17 percent of the sample consisting of sand and 3

percent consisting of silt. Boulders weighing more than 2,000 pounds are

scattered throughout the alluvium (fig. 10).

A 150-pound glacial till sample was collected near piezometer no. 8

(plate 2, fig. 11). Till exposed above the water table in the CAT trench was

dense and well-compacted and was difficult to excavate with the CAT. A blow

from the pOinted end of a rock hammer would only penetrate the till about 1

inch. When the till became water saturated, it would flow easily. The

material analyses for the till is also shown in figure 9. The cumulative

probability plot for the different particle size distributions indicates that

the till consists of 53 percent sand and 9 percent silt. Glacially rafted

boulders weighing upwards of 20,000 pounds tend to be most prevalent along

the glacial bench east of Delta Creek (fig. 10).

-17-

Figure 8. Three-foot vertical section of Delta Creek alluvium exposed in CAT trench near piezometer no. 8 (plate 2). Alluvium is poorly sorted and consists of boulders, gravel, sand, and some silt.

-18-

ENGINEERING GEOLOGY LABORATORY

Particle Size Distribution Curve

A.8.T.M. Cla •• lflcatlon Boulders!

100 Cobbles Gravel Sand Sill Clay I

90

80

\ \

I' \

• --- - -- ----- r-- -- - -. --._.

~\ \ .~ 'e~ SE dim. \- --- -- f--- _. - -- ..

- 70 z: CI

•

\ 1'1~

1\ I \ '11.. I

\ ...... ---- - -.-- . --_ . .

\ I

.c-_ .. .. 1---( laci ~ 60 f--- 1--f-. ------ ... --

>-.Il ~

f\ ~ _. __ . • 50

~ --. - .- .-

C

LL - 40 c •

~f\ vS lreal I~ ri.~-, -1-- -. 1\

f---._. ---- 'r- . ---- ..

u ~ • 30 4.

20

~ ~~ -

1\ +- -.' .-

~ --- -- ... -- --'---

'\ ---- - - -- --

~ r\ t- - -_ ...

~<~ _. __ . ~ .. ._-~- .

h '" "-

"'-k _ .. -----10 I-- . -_.

jI ._--

.- -- f----

~ • ~ ". " ~,

100 10 0.1 0.0 1

Particle 81ze Dlame.er In Mlillme.er.

Figure 9. Particle size distribution curves for stream alluvium, glacial till, and suspended sediments. Stream alluvium and glacial till samples were collected above the water table. Stream alluvium was sampled near piezometer no. 6 and till was sampled near piezometer no. 8 (plate 2). Suspended sediment sample was collected at Upper Delta Creek discharge site (plate 1).

-19-

. ._--

. -

-."._--

-----

-- -

1------

0.0 01

Figure 10. Picture of King Covels CAT at work trenching alluvium for a piezometer installation. Note large boulders in the alluvium and the large glacially-rafted boulders on the glacial bench in the background.

-20-

Figure 11. John Reeder collecting a 150-pound till sample in the CAT trench near piezometer no. 8 (plate 2).

-21-

SEISMIC REFRACTION SURVEYS

Three seismic refraction surveys were conducted in the vicinity of the

proposed weir site to determine depth-to-bedrock and thicknesses of overlying

glacial till and stream alluvium. A Geometrics 12-channel signal enhancement

seismograph was used for the surveys. An average of 5 pounds of high

velocity Kinepak explosives per shot and instantaneous blasting caps were

used for energy sources. As shown in Plate 2, locations for the profiles

are: a 550-foot geophone line (50-foot spacing) trending N-S along Delta

Creek and Clear Water Tributary (1090 ft long, Au - AD profile, fig. 12); an

1100-foot geophone line (100-ft spacing) trending N-S on the glacial bench

east of Delta Creek and the Clear Water Tributary (1280 ft long, Bu - BD

profile, fig. 13); and a 55-foot geophone line (5-ft spacing) trending N-S

across the proposed weir site (65 ft long, Cu - CD profile, fig. 14).

The seismic refraction method consists of measuring the initial arrival

times of compressional seismic waves at points along a line by means of

geophones. The elastic compression waves refract at various geologic

boundaries according to Snell's Law. Based on this law, the velocities of

and depths to interfaces between layers of differing density can be

calculated from the initial arrival time with respect to distance from the

energy source (shot point). The specific analysis technique used in this

study is called the "time intercept method" as described by Dobrin (1960).

The seismic profiles shown in figures 12, 13, and 14 represent corresponding

arrival times versus distance from the shot point.

The velocities found for glacial till vary between 5,820 and 7,520

ft/sec. Bedrock velocities were found to vary between 10,000 and 13,000

-22-

ft/sec. This is the approximate velocity range for a metasedimentary rock

(Dobrin, 1960), which is the assumed bedrock type beneath the site. The

depth-to-bedrock along the 1090-foot profile (fig. 12) is approximately 150

feet on the south end and 190 feet on the north end. The depth-to-bedrock

along the 1280-foot profile (fig. 13) is approximately 320 feet on the south

end and 225 feet on the north end. Beneath the weir site, the bedrock is

approximately 170 feet deep. Along the 1280-foot seismic profile, Bu - BD,

low surface material velocities of approximately 1800 ft/sec are inferred for

a shallow layer from 15 to 40 ft deep. This may represent a loosely

compacted glacial outwash which overlies the till. Glacial outwash features

are evident on the photos for this area (plate 1). The alluvium beneath the

weir site has an average velocity of 4,200 ft/sec (fig. 14). Based on

seismic profile Cu - CD the alluvium varies between 10 and 12 feet in

thickness. Near piezometer no. 8 the alluvium was found to be between 6 and

8 feet thick in a CAT trench which bottomed in glacial till.

-23-

120

100 Slope = rr:Itl U)

080 z --0 ..... .....

<.J -..... UJ U) - 60 ..... ...J .....

---...J

:E o

c 40 SIOpe.~ SIOP.·~ UJ

2 - 20 ~

If ~ I ..

* I A ; '. 6 I,h I', I,~

GEOPHONES - ---Till ~ = 613,9 fls

----------------------Bedrock Vz- 12,612 f/'

NO 400 600

LINE DISTANCE in FEET

Figure 12. Seismic refraction profile Au - AD for 550-foot line along Delta Creek and the Clear Water Tributary (plate 2). of figure represents first arrival seismic travel times and of figure represents velocity model. A geophone spacing of used.

-24-

-

trending N-S Upper part lower part 50 feet was

SHOT PT.

l

1000 s

140

C/) 01 Z o (.)

&&.I ~ 100 ..J ..J

2 1: 80

/

/ /

/

I 2

Slope· 11,776

/

I I I I I 3 .. II 6 7

GEOPHONES

I I .' a

" "

I 10

" " "

6

I I * II 12 SHOJ. "T.

~~---------------------~-------------u

i * ZC&&.I 0&&.1&&.1400 j::C/)1L Till VI = 6883 C &&.I I: '2J'V'\ »'_ OJVV

&&.Io..J __ _ ..Jm~ 200 - - - - __

---- - --- --&&.IC&&.I Bedrock Vz • 1Q,582

..J IOOO~--~~--~400~--~~~~--~~~---"IOOO~---"I~~~ LINE DISTANCE in FEET

Figure 13. Seismic refraction profile Bu - BD for 1,100-foot line trending N-S on glacial bench above Delta Creek and the Clear Water Tributary (see plate 2). Upper part of figure represents first arrival seismic travel times and lower part of figure represents velocity model. A geophone spacing of 100 feet was used,

-25-

12

en 010 Z o (;)

IAJ enS. ...J ...J

2

./ /,

t:. -L Slope a 6381

'" '"

o o

" 1 o Slope.~

0* 1 1 1 I I I I I I I * SHOT PT. 1 2 3 4 5 , 1 • • 10 II II SHOT PT.

GEOPHONES

* 432

N 0

------1 Alluvium V, = 4230 fls

....... _- .......... - --- -Till Vz= 6683 fls s

Figure 14. Seismic refraction survey profile Cu - CD for 55-foot line

trending N-S along Delta Creek at proposed weir site (see plate 2). Upper part of figure represents first arrival seismic travel times and lower part of figure represents velocity model. A 5-foot geophone spacing was used.

-26-

HYDROLOGY

Surface Water and Sediment Transport

The Delta Creek watershed is situated on the southern flanks of Mount

Dutton. These flanks face the Pacific Ocean and receive substantial

precipitation from passing Pacific storms, which are most common between

summer and mid-winter.

mid-winter to spring.

Dryer storms from the Bering Sea are most common from

Increased discharge will occur in Delta Creek during

any storm that contains significant precipitation. Precipitation falling

during the winter is usually stored in the snow pack at higher elevations

until it melts in spring and summer. Because of the maritime environment for

this region and its mean annual temperature of 38°F, heavy rainfall and

runoff can occur even in winter.

Figure 15 is a 1982 hydrograph for Russell Creek near Cold Bay (fig. 1).

The hydrograph shows numerous high water flow periods which occur during and

after storms. Russell Creek drains the eastern and northeastern slopes of

Frosty Peak, a Quaternary volcano like Mount Dutton. Low water flows

occurred for Russell Creek between February and the middle of May. Short

periods of high water flows occurred throughout the rest of the year. High

surface flows occurred during September and October. May through August also

marked a period of continuous high surface flows; however, this is probably

partly due to snow pack and glacial melt. Because Russell Creek and Delta

Creek are in similar hydrologic environments, it is felt that their

hydrographic discharges would be roughly similar.

While the field work was underway for this investigation, a

southeasterly storm occurred on the evening of August 23. The storm caused

-27-

2000

1100

1100·

1400, >-• I .. I ... 1100r---r I • It.

(J

• 1000r- I .. • .. • 100; • <C

eool

4001

"Q 1111 1 •• 2

• • .! .. 20 Q."Q E­; ..... 10 • iie 3~ coCO • • - O+--O~c-t-_-'~H~o-v-.-'~D-.-c-.'-·JLa-n-.~~F~.~~-.~Ir-~U~a-r.~'-A~.-r-.~Ir-u~a-y--rlr-Ju-n-.-'--J~u~l-y-'---A~u-g-.-'--S-.-p-t."

" ..... , Cr •• k H •• r C.,4Ii •• Y. AI •• ka

L.t. II 10' 10· Lu,. 111 41' 01·

Figure 15. 1982 discharge hydrograph for Russell Creek near Cold Bay (fig. 1). Suspended sediment data for four samples is shown in lower graph.

-28-

Delta Creek to rise and overflow its banks. The high water was impossible to

cross on August 24, and therefore the weir site was inaccessible. The water

in the channel rose almost 1 foot and flooded many of our previously

installed piezometers (fig. 16). The water in Delta Creek, which was

previously milky-white in color, changed to a muddy-brown color. Yet, the

water in the Clear Water Tributary rose only 2 inches during the storm and

remained crystal clear.

Prior to the storm, discharge measurements were taken on August 23 at

the powerhouse site and just upstream from the proposed weir site (plate 1,

App. A-I and A-2). After the waters in Clear Water Tributary had subsided

from the storm, a discharge measurement was taken (App. A-3).

A discharge measurement of 54.3 cfs± 8 percent was measured at the

powerhouse site, and a discharge of 57.8 cfs± 10 percent was measured at the

proposed weir site. Of the 57.8 cfs± 10 percent, 42.0 cfs was measured in

Delta Creek above the Clear Water Tributary and 15.8 cfs was measured in the

Clear Water Tributary. The discharges at the weir site and powerhouse site

are similar. Some surface water loss due to ground water storage probably

was occurring between the weir and the powerhouse sites during our visit,

since several small tributaries were flowing into Delta Creek between the

weir and powerhouse sites and the measured discharge upstream was found to be

larger. It would be expected that some of the ground water would be released

during periods of very low flow, such as in winter.

The Clear Water Tributary has a drainage basin area of approximately 1.4

square miles. The Delta Creek drainage basin area above the Clear Water

-29-

Figure 16. Delta Creek high water flow the day after the August 23, 1984 storm. Creek overflowed its banks in many places. Weir crosses where gravel island occurs.

-30-

Tributary confluence is approximately 2.0 square miles. Collectively, this

represents a total drainage area of 3.4 square miles. The Clear Water

Tributary contains 41 percent of the total drainage area but only 27 percent

of the flow. No glaciers exist in the Clear Water Tributary drainage basin.

A glacier with an approximate 0.39 square mile area exists in the Delta Creek

drainage basin. The higher discharge rate per drainage basin area for Delta

Creek is probably due to glacial melt water. The gap between the discharge

measurements for Delta Creek and the Clear Water Tributary would probably be

narrower during winter when glacier and snow pack melting at higher

elevations is negligible.

After the high water from the storm had subsided, extensive storm

related sand and silt deposits were observed along Delta Creek. Figure 17 is

looking south before the storm and figure 18 is looking northeast at

approximately the same location after the storm. Prior to the storm and

while taking the stream discharge measurement at the powerhouse site, the

stream discharge wading rod tended to sink continuously in loose sand, making

the discharge measurement somewhat difficult to obtain. During the storm,

large boulders, cobbles, and pebbles could be heard moving along the Delta

Creek stream bottom.

After the storm waters partially subsided, a 500 milliliter water sample

was collected on August 25 at the upstream Delta Creek discharge site. The

sample was collected one inch from the water surface at the approximate

position of maximum surface water velocity (i.e., sta. 17.5 ft, App. A-2).

This sample contained 0.7 gram of suspended sediment, of which 52 percent was

sand (fig. 9).

-31-

Figure 17. Looking south from weir site just before August 23, 1984 storm.

-32-

Figure 18. Looking northwest from weir site two days after storm (August 25, 1984). Note sediment deposition differences between this and the previous photo.

-33-

Two different diversion weir structures have been proposed for this

project. One weir would have a 4.5 foot water level (Dowl Engineers et al,

1982), and the other weir would have a 8.0 foot water level (APA design).

The 4.5 foot diversion weir would create a reservoir volume of 9,100 cubic

feet, and the 8.0 foot diversion weir would create a reservoir volume of

40,600 cubic feet.

In order to make an estimate on how long it would take for the two

reservoirs described above to fill with sediment, the following assumptions

were made: (1) average suspended load for the stream is 0.7 grams per 0.5

liter; (2) 52 percent of the suspended load is sand; (3) the average

discharge for Delta Creek above its confluence with the Clear Water Tributary

is 42.0 cfs; (4) the Clear Water Tributary contains no suspended sediments;

(5) all suspended sand will settle and be deposited behind any diversion weir

structures while all other suspended sediments will pass over or through the

structure; and (6) the dry bu"lk density for settled sand is 122 pounds/ft3

(Hough, 1969). Based on the reservoir volumes and the assumptions described

above, the 4.5 foot diversion weir reservoir would be filled with sand in 6.6

days, and the 8.0 foot diversion weir reservoir would be filled with sand in

29.2 days. In actuality, the upper foot or so would probably not fill with

sand because of turbulent water flow, and the sand would most likely be

transported over the top of the weir structure or through the penstock.

Independent of the validity of the above assumptions, it should be emphasized

that these calculations are based on only one suspended sediment sample which

mayor may not be the statistical norm for suspended sediment load in Delta

Creek. The suspended sand will need to be addressed in the final weir

design.

-34-

Most of the suspended sand in Delta Creek is probably being eroded from

the Quaternary glacial tills which blanket the drainage basin. The particle

size distribution plot for the glacial till that was collected near

piezometer no. 8 showed 52 percent sand (fig. 9). During the Holocene, Delta

Creek eroded and transported a large volume of sediment. Between the

powerhouse site and the proposed weir site, Delta Creek flows through a

canyon that is approximately 50 feet deep and 100-300 feet wide. The canyon

was cut into glacial tills. These eroded glacial deposits, and other eroded

glacial deposits from upstream, have been deposited on the large alluvial fan

located between the airport and the powerhouse site (fig. 7). The airport

gravel quarry is located on this alluvial fan.

Einstein (1950), after extensive field work in the western United States

and after extensive laboratory experimentation, developed an empirical

derivation for total sediment transport in streams. Colby (1961) revised

Einstein's procedure and empirically derived discharge of sediments at 60°F

with respect to water depth and mean water velocity. In figure 19, Colby

shows such a relationship for a streambed of well-sorted (0.3 mm median

diameter) sand. Bed material discharge in figure 19 means bedload sediments

plus suspended sediments being transported by flowing water. By using figure

19, an empirical calculation of total bed material discharge can be made for

the upper Delta Creek discharge measurement site by determining the sediment

transported for each section of velocity measurement (App. A-2) and then

adding them together. The calculation comes to 244 tons/day. If an average

depth and velocity of 1.0 feet and 3.33 feet/second respectively is assumed,

then the Delta Creek channel at the upper discharge measurement site will

need to be 12.73 feet wide. Based on figure 19, the discharge of sand for

-35-

J: ~ 1000 0

:;: L>-

a ~ a a L>-

0::: 6 w 0-

100

r <I 0

0::: W 0-

U) 3 z a ~ 10

Z --

-' <I

0::: W

~

<I ::;;

0 1.0 W ID ~s

L>-

a w C)

0:

<I J:

~o

u UJ - 0.1 0 0.1 1.0 10 100

DEPTH. IN FEET

Figure 19. Shows the affect of depth on the relationship between mean velocity and empirically determined discharge of total bed material (i.e., suspended and bed load sediment) for a well sorted 0.3 mm median diameter sand channel at 60°F (Colby, 1961).

-36-

this simplified channel would be 19.35 tons/day per foot width of channel, or

246.33 tons/day. Sand deposition of 84.89 tons/day was calculated using the

sediment data derived from the water sample collected; namely, 0.7 grams per

0.5 liter of which 52 percent is sand. The 84.87 tons/day of sand

calculation is far below the 244-246 tons/day empirical calculation.

In actuality, the Delta Creek channel alluvium consists mostly of

boulders and gravel with only 20 percent sand or finer sediments (fig. 9).

Therefore, the actual sand transport in Delta Creek would be expected to be

less than the empirically estimated sand transport. The calculations derived

from the water-sample suspended load may not be unreasonable since the values

were much lower than that estimated by the Colby-Einstein technique. The

U.S. Geological Survey, in monitoring the Chulitna River near Talkeetna,

Alaska, has recorded suspended load values as high as 0.715 grams per 0.5

liter for flowing water having a mean velocity of 8.2 feet/second and a

0.0014 (7.4 ft/mi) channel slope gradient (Knott and Lipscomb, 1983). Delta

Creek at the weir site had a channel gradient of 0.055 (290 ft/mi) and an

average flow velocity of 3.3 feet/second. At such a high gradient, large

suspended sediment loads would be expected.

For Russell Creek near Cold Bay, the suspended sediment transport was

0.39 tons/day in January, 7.6 tons/day in June, and 30 tons/day in September

(Lamke et al, 1983). The gradient at the discharge site on Russell Creek is

only 0.002 (10.5 ft/mi). One percent of the Russell Creek drainage basin

contains glacial ice. Based on this information it would seem that the

suspended sediment transport for Russell Creek would be much lower than that

for Delta Creek. This assumption may be realistic since the total calculated

-37-

suspended-sediment transport for Delta Creek on August 25, 1984, was 158.6

tons/day.

During the August 23 storm and resulting high water, we heard pebble,

cobble, and boulder-size bedload material moving along the Delta Creek stream

bottom, which suggests significant bedload transport. The large alluvial fan

near the airport and the high stream gradient (0.005 slope or 26.4 ft/mi)

also suggest significant bedload sedimentation. The general lack of brushy

vegetation along the Delta Creek canyon bottom indicates that Delta Creek

overflows its channel frequently during storms. Based on the above, bedload

sediment transport should be investigated for Delta Creek.

In contrast, the Clear Water Tributary canyon bottom contains a

continuous moss cover which indicates the stream does not overflow its banks

very often (fig. 6).

Both the suspended sediment and bedload transport are considered to be

fairly low for this tributary drainage. For example, even during the peak

flow period from the August 23 storm, the water in the tributary was crystal

clear.

It is not unusual for stream bedload transport in the western United

States to be an order of magnitude less than suspended load transport (Colby,

1961). This relationship appears to hold for streams examined in the Susitna

Valley of Alaska also (Knott and Lipscomb, 1983). The calculated total

suspended-sediment transport for Delta Creek is 158.6 tons/day. This again

is based on the surface water sediment sample we collected. Average bedload

-38-

sediment transport for Delta Creek would therefore be about 10 percent of the

158.6 tons/day or 16 tons/day. We suspect this estimate is probably lower

than what is actually being transported.

To assist in future investigations of the bedload transport for Delta

Creek, a one-foot wide strip of stream alluvium was painted bright red across

the entire canyon floor bottom (plate 1, fig. 20 and 21). If this paint

sticks to the alluvium, then any changes due to the channel scour or

deposition can be noted. Scour chains have been used in the western United

States for the purpose of determining the depth of channel scour (Leopold et

al, 1964). Scour chains were not installed in the coarse alluvium of Delta

Creek because of difficult excavation conditions.

Suspended load sediment transport for most glacial streams in Alaska is

1-4 orders of magnitude higher during spring, summer, and fall than during

the winter (Lamke et al, 1983). Stream bedload transport is usually at a

minimum during the winter. Most winter precipitation is stored as snow or

ice and glacial melt is low. In the winter, if channel bank ice is present,

it helps protect the banks from being eroded. Recent studies by Knott and

Lipscomb (pers. commun., 1984) for the Susitna River drainage indicate the

bedload transport in the winter is much smaller than the suspended sediment

transport. Because this region has a mild maritime climate large sediment

transport could occur in glacial streams anytime during the winter.

Ground Water

Ground-water seepage beneath the proposed Delta Creek weir was one of

APA's primary concerns. To investigate this problem, an array of 10

-39-

/

Figure 20. Shows the 1 foot wide red stripe painted across the Delta Creek canyon bottom above the proposed weir site on August 24, 1984 (see plate 1). Future channel scour or deposition can be monitored using this stripe.

-40-

I ~ ~

I

/

Figure 21. Looking up Delta Creek at painted stripe and survey stakes, August 24, 1984.

piezometers were installed (plate 3) in the vicinity of the proposed weir

site. Hydraulic conductivity for the alluvium was determined by performing

slug tests on each piezometer. These tests required measuring the rate of

water infiltration for each piezometer after it was filled with water. The

hydraulic conductivity values were used with the Darcy equation and

appropriate flow nets to calculate ground-water seepage under the two

proposed weir designs.

The design and dimensions of the piezometers used are shown in the upper

part of figure 22. Each piezometer consisted of a 47.8 cm long sand screen

(manufactured by Mark Controls Corp., trade number SBD 2460) threaded into a

coupling that was attached to a 5 foot long steel pipe. The CAT was used to

trench to the water table at the pre-selected piezometer sites (fig. 10).

The piezometers were then driven into the alluvium and till using a 30 pound

fabricated driver-hammer device. Each piezometer was driven into the

sediments until the top of the sand screen was several inches below the water

table. Fine sand and silt was then hand packed around the piezometer pipe

before backfilling. Hand shoveling and the CAT were used to backfill around

the installed piezometers. The trenches were backfilled as much as possible

to their original state. The piezometer array was then surveyed for control

(plate 2). Piezometer spacing was measured using a Brunton pocket transit

and a 300-foot tape, and elevations between the top of the piezometer pipes

were measured using a hand level and survey rod. Horizontal accuracy between

piezometers is ±2 feet, and vertical accuracy is ±1 foot. The ground-water

table was then measured at each piezometer. The ground-water table has been

contoured from this data and is shown on plate 3.

-42-

h Ho

Delta Creek, King Cove, Alaska ~~--~--~--~---r---r---r~~----~----------------------,

\ [J Piezometer No. 10, To = 225 seconds

L=478mm = 47.8cm=0.478m r= 17.5mm = 1.75cm = 00175

R= 22.!Smm z 2.25cm=0.0225m

Figure 22. Slug test data for piezometer no. 10. Piezometer schematic is also shown.

-43-

Delta Creek, King Cove, Alaska 1.0

o PiezOtnlter No. I , To= 7.5 seconds

.7

o Piezometer No.2, To= 46.5second1

l\' 0 PiezOlMtw No.3, To = 4.5 seconds

r'\. o Piezometer No.4, To= 12.5.econds

~ .. "", • Piezometer No.5, T6= 12.5 seconds

[\. • Piezometer No.6, To = 110 seconds

~ \\\ • Piezometer No.7, To = 69.0McOndS

~ • Piezometer No.9, To = 30.0 seconds

'\ \~ ~ L=478mm = 47.8cm=.478m

~ r= 17.~,"", = 1.7~cm: .017~m R: 22 .5mm: 2~m:.022l5m

~ 1\ "\

1'\ \. l\.-

I

\ \ \ ~

~ 1'\ 1\ ~

\ \ ~ \\ ~

~\ \\ ~ ~~ ~ ItO \

~ i "\ ~.

~ ~ ~ \. ~

" ~ \ ~ 1\\

~

\ \ \

\ \ \ • \ \ \

.9

.8

.6

.5

.4

.3

.2

.I a 10 20 30 40 ~ eo 7'0 9J 90 100 110 120 I~ 140

Secondl

Figure 23. Slug test data for piezometers 1, 2, 3, 4, 5, 6, 7, and 9.

-44-

Slug tests were performed by quickly filling each piezometer using a

gasoline engine pump, and then measuring the water level drop with time. A

battery operated water level indicator (Watermarker manufactured by Johnson

Division of U.O.P., Inc.) and a stop watch were used. The water levels

dropped rapidly for each test performed and required fast data recording.

Data for the slug tests show an exponential decline in water level drop with

respect to time. The straight lines on the logarithmic graphs shown in

figures 22 and 23 represent the normalized pressure-head difference between

the water table and the piezometer water level with respect to time.

Hydraulic conductivities for the sediments surrounding each piezometer

were calculated using the slug test data. The calculations assume that the

sediments are homogeneous, isotropic, incompressible, and infinite in volume,

and that the ground-water flow is laminar and incompressible. Given the

above criteria, Darcian ground-water flow will occur where the rate of water

flow out of the piezometer screen is proportional to hydraulic conductivity,

K, of the soil and to the pressure head of the piezometer with respect to the

water table. Assuming the above situation, Hvorslev (1951; and described by

Cedergren, 1967) has shown if L/R:;::. 8, that:

K = r 2 1n(L/R) ; 2LTo

where K = hydraulic conductivity; r = inside radius of steel piezometer pipe;

L = length of piezometer screen; R = outside radius of screen; To = basic

time lag which is equivalent to the time value when h/Ho = 0.37, and h =

water level height in the piezometer above the water table at any given time

and Ho = water level height in the piezometer above the water table after the

piezometer has been filled (i.e., at time = zero for the test). The To

values for each slug test as shown on figures 22 and 23 are as follows: TOlD

-45-

= 225 seconds; T09 = 30 seconds; T07 = 69 seconds; T06 = 17 seconds; T05 =

12.5 seconds; T04 = 12.5 seconds; T03 = 4.5 seconds; T02 = 46.5 seconds; and

T01 = 7.5 seconds. Based on Hvorslev's calculation, Equation (1), the

following hydraulic conductivities for the sediments surrounding each

piezometer are:

KlO = 1.43 X 10-5 ft/sec = 1.23 ft/day;

Kq = 1.07 X 10-4 ft/sec = 9.25 ft/day;

K7 = 4.65 X 10-5 ft/sec = 4.02 ft/day;

K6 = 1.89 X 10-4 ft/sec = 16.32 ft/day;

K5 = 2.57 X 10-4 ft/sec = 22.20 ft/day;

K4 = 2.57 X 10-4 ft/sec = 22.20 ft/day;

K3 = 7.14 X 10-4 ft/sec = 61. 67 ft/ day;

K2 = 6.91 X 10-5 ft/sec = 5.97 ft/day; and

Kl = 4.28 X 10-4 ft/sec = 37.0 ft/day.

The lowest hydraulic conductivity value, 1.43 X 105 ft/sec for

piezometer no. 10 (K10 ) is in the range of silty sand, and the highest value

of 7.14 X 10-4 ft/sec for piezometer no. 3 is within the range of sandy

gravel. The hydraulic conductivity values for various sediments are

summarized by Freeze and Cherry (1979). The large variation in hydraulic

conductivity values is probably due to the fact that the alluvium is not a

homogeneous and isotropic sediment as assumed.

Piezometer no. 8 was installed in glacial till (fig. 11). The first

slug test on this piezometer was unsuccessful because, when the pipe was

filled with water, the till sediments surrounding the screen failed and a

"blowout" occurred. A "blowout" is when the water flows up the outside of a

-46-

piezometer pipe to the surface (i.e., the seal around the piezometer has been

broken). In a "blowout" the pumped water can flow out so fast that the

piezometer cannot be filled. When this occurred with piezometer no. 8, we

moved it to a new location and tried another slug test. This time a

fast-setting concrete designed for underwater application was packed around

the piezometer in hopes of sealing it. After pumping water into the pipe, a

second IIblowout ll occurred within 4 seconds. The slug test for the glacial

till piezometer was then abandoned. Two other IIblowouts" occurred for two of

the piezometers installed in the alluvium. These piezometers are shown in

figure 23 and they are identified with the notation IIseal breakingll. The

IIblowouts ll fortunately occurred long enough into the test so that reliable

conductivity values were obtainable. The occurrence of IIblowouts" during our

slug tests points to the possibility of ground-water piping underneath the

weir structure especially if the weir is placed on glacial till. Remembering

that the glacial till consists primarily of sand and silt, and that it is

well-compacted, suggests that it would have a very low hydraulic

conductivity.

Freeze and Cherry (1979) describe the simple Hazen empirical approach

for determining hydraulic conductivity based on grain size diameter. This

relationship is: K = dID; where K = hydraulic conductivity (cm/s); and dID =

grain size diameter (mm) at which 10 percent by weight is finer. Using the

Hazen approach and a dID of 0.5 mm for the alluvium near piezometer no. 4

(fig. 9), the K for the alluvium will be equal to 0.25 cm/sec (8.2 X 10-3

ft/sec or 708 ft/day). Using a dID of 0.083 mm for the glacial till (fig.

9), the K for the glacial till will be equal to 6.9 X 10-3 cm/sec (2.26 X

10-4 ft/sec or 19.5 ft/day). The hydraulic conductivity for the material

-47-

surrounding piezometer no. 4, as determined from the slug test, was 2.57 X

10-4 ft/sec, which is 32 times lower than the Hazen empirical estimate. The

Hazen approach was derived in a laboratory test using well-sorted sands.

Because the alluvium and the glacial till are not very well sorted, the

previous Hazen empirical estimates for hydraulic conductivity are considered

to be poor. Because we were unable to obtain the hydraulic conductivity of

the glacial till with piezometer no. 8, an empirical estimate is presented

below. In the previous Hazen approach calculation, the K for glacial till is

36 times lower than the K for alluvium. It is assumed that this ratio for

hydraulic conductivity holds. The average hydraulic conductivity for the

alluvium, using the Hvorslev calculation, is 2.31 X 10-4 ft/sec or 19.98

ft/day. Assuming this value represents the K value for the material actually

collected near piezometer 4, then the glacial till would have an approximate

K value that is 36 times smaller than the average K value for the alluvium

(6.42 X 10-10 ft/sec or 0.55 ft/day). Naturally, this is only a rough

estimate for the hydraulic conductivity of the glacial till. In actuality

one should expect even a smaller value due to the dense compaction of the

till.

The approximate saturated ground-water flow through the alluvium can be

calculated using the well known Darcy equation: Q = A!t K; where Q = total

discharge across a vertical cross-section; A = area of vertical

cross-section; jt = unconfined water table gradient perpendicular to the

vertical cross-section; and K = hydraulic conductivity of material at the

cross-section. The alluvium beneath the proposed weir site is approximately

10 feet thick. The water table is about 2 feet deep, thus 8 feet of alluvium

is saturated with ground water. Beneath the weir site the alluvium is

-48-

approximately 100 feet wide, and it has an average K value of .00023 ft/sec

which was previously calculated from the slug test. Using this information

and the Darcy equation, the total ground-water flow beneath the weir site is

about 0.015 cfs or 1,300 ft 3 /day.

Based on the theory of saturated ground-water flow, Polubarinova-Kochina

(1939) has determined the two-dimensional confined flow per unit normal to

the direction of flow underneath various weir structures (fig. 24a). If a

sheet pile weir was built so that the sheet piles penetrated the 10 feet of

alluvium, and if the surface water head on the reservoir side was 8 feet,

then seepage estimates under the weir can be made using figure 24a. One such

estimate for seepage assumes that the sheet pile foundation rests entirely in

glacial till that is 200 feet thick. The estimated hydraulic conductivity

value of 6.42 X 10-6 ft/sec for the till is considered to be representative

throughout its entire thickness. Applying this information to figure 24a,

the SIT will be 0.05, and the bit will be o. Then q/Kh will equal 1.2375,

where q is the quantity of ground-water flow per unit normal to the direction

of flow, K is the hydraulic conductivity of the till which is 6.42 X 10-6

ft/sec, and h, the total head behind the weir, is 8 feet. This assumes that

the ground surface adjacent to the downstream side of the weir represents the

water table. If the weir is 116 feet long, and assuming no piping occurs

beneath the weir and that only two dimensional flow occurs, then the total

seepage would be 7.0 X 10-2 cfs or 637 ft 3 /day. If we took the highest

hydraulic conductivity value for the alluvium, K = 7.14 X 10-4 ft/sec, and

substituted this K value (we are assuming 200 feet of alluvium and no till),

then the total seepage flow would be 0.88 cfs or 7.57 X 104 ft 3 /day. The

actual seepage flow is probably between these two extreme cases.

-49-

q kll

0.8

0.6

0.4

1.5

1.4

1.3 \

\ 1.2

\ 1.1

1.0

0~77~7-~-7~~-7~~~~~~ o . 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 sir

~ __ I ~ositioJn A I

~ --- Position 8 or 8'

~ I I I I

biT = '12 \\ f-- i ~ "-k1b}T= '}4

T~~ ~ ~ --,,,:::::-- :::::--.-

T

(a)

l'"~~ ! bIT='£. --'.::::-::::-~ I-

0.2 ~d~,\\;L\\0~"~It;,~G0'\\\I/l\\'

o o 0.2 0.4

sir

I

0.6 0.8

(b)

Figure 24. Seepage volumes beneath weir structures per unit normal to the direction of flow divided by hydraulic conductivity and total pressure head. (a) Polubarinova-Kochina, 1952; (b) Harr, 1962.

-50-

Another procedure often used for estimating seepage flow beneath dam

structures is the construction of a flow net which consists of a set of

equipotential lines and a corresponding set of orthogonal flow lines. A flow

net for the sheet-pile weir structure is shown in figure 25. In constructing

the flow net, the alluvium and till are considered to be homogeneous,

isotropic, and water saturated. In figure 25, the foundation base for the

sheet pile is 7.5 feet deep. It would probably be a good idea not to disturb

the glacial till during construction. A total seepage flow can be calculated

by combining the flow net with the Darcy equation. Assuming only two­

dimensional flow, a weir length of 116 feet, an average K of 1.87 X 10-4

ft/sec for the alluvium, and a K of 6.42 X 10-6 ft/sec for the till, then

total seepage flow, Ql16' would be 4.04 X 10-2 cfs or 3,490 ft 3 /day. This is

our best approximation of seepage flow for this design.

If the same weir design were constructed on the Clear Water Tributary at

the proposed DGGS site (plate 1), then the total seepage flow would be 4.4 X

10-2 cfs or 3,800 ft 3 /day. This calculation contains the same assumptions

and similar conditions as used for the Delta Creek site, except that the K

value for the alluvium is 4.28 X 10-4 ft/sec (value determined from

piezometer no. 1) and the weir length is 60 feet.

A 15-foot wide concrete apron weir as described in the Dowl Engineers

report (1982) has also been proposed. The weir design has a water head of

4.5 feet, and a basal apron foundation depth of 2.5 feet (fig. 26). A

calculation for seepage flow beneath this weir design can also be done using

figure 24a. In this calculation it is assumed that the glacial till is

impermeable. Seepage flow is not affected much by the position of the

-51-

5X Enlargement

8'

1-=10'

.hee~le 10' high 7.5' deep

~~---------8.0"-----r--'---+-~--Jr--------0'·---------

10' AlluviuM

I' ~~-----I.O~'----------------------~~--------------------------O'~------------

10'

190'

7.2'

8.4'

Fi gure 25. site.

6.8'

AlluviUM

0.8~

Glacial Till

1.8'

~

Bedrock

Flow net for a 7.5 foot deep sheet-pile weir at proposed weir

-52-

concrete apron legs (Harr, 1962). Figure 24b shows that a leg placed under

the middle of the apron, or under one side results in little seepage

difference. If the foundation contained a single 2.5 foot leg positioned

under the middle of the apron, then SIT is 0.25, biT is 0.75, and q/Kh is 0.4

(fig. 24a). In the above calculation, q is ground-water flow per unit normal

to the direction of flow, K {2.31 X 10-4 ft/sec or 19.96 ft/day)is the

average hydraulic conductivity calculated for the alluvium and h (4.5 feet)

is the total head behind the weir. If no piping occurs, and if the flow

beneath the weir is two-dimensional, then the total seepage flow under this

weir, which is 93 feet long, would be 3.87 X 10-2 cfs or 3,340 ft 3 /day.

A flow net was also constructed for this weir design as shown in figure

26. In calculating the seepage flow for this weir design, the same

conditions and assumptions were used as applied to the sheetpile weir

flow-net calculations. The alluvium and till are homogeneous, isotropic,

water-saturated, and are assumed to contain only two-dimensional flow. The

average K determined from piezometers 4, 5, 6, and 7, which are the closest

to the weir, is 1.87 X 10-4 ft/sec. The K for the till is 6.42 X 10-6

ft/sec. Combining the Darcy equation and flow net shown in figure 26, the

total seepage flow beneath a 93 foot long weir would be 2.39 X 10-2 cfs or

2,065 ft 3 /day. This is our best approximation of seepage flow for this

design.

If this same weir design were constructed on the Clear Water Tributary

at the proposed DGGS site (plate 1), then the total seepage flow would be

2.26 X 10-2 cfs or 2,390 ft 3 /day. This calculation contains the same

assumptions and similar conditions as used for the Delta Creek site, except

-53-

5X Enlargement t4

'I

' 4.I' __ r-~r--r~~ __ ~L1_._=_10_' ____ .-<r-'~~~_0'-________ __

Allyv'",

10'

4." ----4.0.' T 10'

0"----Allyv'UM

Glee'a. TIU

.-J.OI'

110'

Figure 26. Flow net for a 15 foot wide concrete-apron weir at proposed weir site.

-54-

Gla.'al Till

that the K value for alluvium is 4.28 X 10-4 ft/sec (value determined from

piezometer no. 1) and the weir length is 50 feet.

Ground-water piping is a major concern in seepage flow calculations.

The IIblowouts ll with piezometer no. 8 in the till and the IIblowouts" with

piezometers no. 2 and 9 in the alluvium are examples of piping. Piping leads

to substantial increases in ground-water flow. Harr (1962) numerically

defines the reciprocal of the maximum exit gradient for seepage flow, IE, as

a factor of safety estimate against the occurrence of piping. Estimates for

IE can be determined from the theoretical work of Khosla et al (1954), whose

results are shown in figures 27a and 27b. IE for a sheetpile weir with a

foundation 10 feet deep and an 8 foot water head is 0.25465 (fig. 27a). This

has a factor of safety of 3.93. IE for the concrete apron weir with a 2.5

foot deep leg and a 4.5 foot water head is 0.246. This has a factor of

safety of 4.06. Khosla et al (1954) recommends a factor of safety of at

least 4 for gravel, 5 for coarse sand, and 6 for fine sand. This suggests

that a concrete apron weir with a 4.5 foot water head may actually be safer

with respect to piping than a sheetpile weir, although piping could be a

problem with either.

-55-

__ C:- b --1

~ IEs 1 II = 1i7f

A=I+~ 2

E

(a)

0.35 t--t--t--I--+-t.--J-.-f-+--+----j

0.05' I

0.3°1\ 0.25 t-\-t-\--+-+-+--+---r---+--J.-J----.j

1S0.20 I\.:

0.15 I'--... 0.10 r! -r--t--ti"'---="i'-;;;::::/--t--+--+-l-­

-f--.....'----,f--...L ......

(b)

0 0 10 20 30 40 50

"/s I

Figure 27. Maximum exit gradient for various weir configurations (Khosla, Bose, and Taylor, 1954).

-56-

POTENTIAL ROCK SOURCES

The best source for competent, angular shot rock is from the rock quarry

situated along the road between King Cove and the airport. The rock in the

quarry would be durable and consists of slightly altered diorite. The

alluvium in the vicinity of the weir site is the best source for coarse

gravel. The alluvial fan near the airport is a gravel quarry source and

contains large volumes of gravel. Gravel for the airport runway came from

this source. Numerous glacially rafted andesite boulders, weighing upwards

of 10 tons are present on the glacial bench east of the weir site and Delta

Creek canyon. Coarse rock fall talus is present west of the weir site at the

base of the mountain. Therefore, whatever the construction specifications

require, several local material sites are available.

-57-

CONCLUSIONS AND RECOMMENDATIONS

Sediment transport is probably the most important condition to be

addressed in the final design phase for the Delta Creek weir site. Total

sediment transport includes both suspended load and bedload. Approximately

50 percent of the suspended load is sand. Most of this sand will settle out

in the reservoir or be transported through the penstock. Bedload consists of

sand and gravel. This material also will be deposited in the reservoir. The

total sediment transport will be substantial from early spring to late fall.

Further study of the annual sedimentation cycle (at least one spring to late

fall cycle) should be considered before a final design and final site

selection is made, especially since our data calculations are based on only

one suspended sediment sample.

If sedimentation is a problem in the final weir-design phase, then the

DGGS alternate weir site should be seriously considered (plate 1 and fig.

28). The only drawback to the Clear Water Tributary is the lower discharge.

If this is a problem only during the winter, then possibly some of the main

Delta Creek flow could be diverted into the Clear Water Tributary reservoir

by way of the coulees.

Seepage losses should be low and not a problem if piping does not occur.

Seepage flow losses in the range of 2,000 to 4,000 ft 3 /day would probably

occur. A concrete apron weir design would probably be less conducive to

piping flow than the sheetpile design. A concrete apron weir might also be

easier to build because the numerous large boulders in the alluvium would not

have to be removed. Also, because the glacial till appears to promote piping

when saturated and disturbed, we recommend that the weir be anchored and

-58-

Delta Creek

Figure 28. Looking up Clear Water Tributary at alternate DGGS weir site. Note recent slump on right (east) bank.

-59-

penetrate alluvium only. Depending upon weir design, further soil

engineering tests of the till may be required especially if the weir

abutments penetrate into the till. At the proposed weir site as based on the

seismic refraction surveys, the stream alluvium is about 11 feet deep in the

middle of the stream canyon and the till is about 170 feet deep.

The air photo lineaments interpreted from the photography may be active

Quaternary faults. There does not appear to be any significant offset

associated with these lineament/fault structures, and our mentioning them is

not intended to inhibit design progress. However, it would be advisable to

trench these structures in order to accurately document their existence and

nature.

-60-

REFERENCES

Biery, G., 1966, King Cove, Alaska, The Buyer, Oct. 5 issue, p. 12.

Black, R.F., 1976, Geology of Umnak Island eastern Aleutians as related to the Aleuts: Arctic and Alpine Research 8(1), p. 7-35.

Cedergren, H.R., 1967, Seepage, Drainage, and Flow Nets: John Wiley and Sons, New York, 489 p.

Coats, R.R., 1950, Volcanic activity "in the Aleutian Arc: U.S. Geological Survey Bulletin 974-B, p. 35-49.

Colby, B.R., 1961, Effect of depth of flow on discharge of bed material: U.S. Geological Survey Water-Supply Paper 1498-0, 12 p.

Dobrin, M.B., 1960, Introduction to Geophysical Prospecting, 2nd ed.: McGraw-Hill Book Company, New York, 446 p.

Dowl Engineers, Tudor Engineering Company, and Dryden and LaRue, 1982, Feasibility Study for King Cove Hydroelectric Project, Vol. B, Final Report to the State of Alaska Power Authority, Anchorage, Alaska.

Einstein, H.A., 1950, The bedload function for sediment transportation in open channel flows: U.S. Department of Agriculture Technical Bulletin 1026, 70 p.

Freeze, R.A., and Cherry, J.A., 1979, Groundwater: Prentice-Hall, Inc., Englewood Cliffs, New Jersey, 604 p.

Harr, M.E., 1962, Groundwater and Seepage: McGraw-Hill Book Company, Inc., New York, 315 p.

Hough, B.K., 1969, Basic Soils Engineering, 2nd ed.: The Ronald Press Company, New York, 634 p.

Hvorslev, M.J., 1951, Time lag and soil permeability in groundwater observations: U.S. Army Corps of Engineers Waterways Experimental Station Bulletin 36.

Jacob, K.H., and Hauksson, E., 1983, A seismotectonic analysis of the seismic and volcanic hazards in the Pribilof Islands - eastern Aleutian Islands region of the Bering Sea: final report to U.S. National Oceanic and Atmospheric Administration under contract NOAA 03-5-022-70, Lamont-Doherty Geological Observatory of Columbia University, New York, 224 p.

Kennedy, G.C., and Waldron, H.H., 1955, Geology of Pavlof Volcano and vicinity, Alaska: U.S. Geological Survey Bulletin 1028-A, p. 1-19.

Khosla, R.B.A.N., Boss, N.K., and Taylor, E.M., 1954, Design of weirs for permeable foundations: Central Board of Irrigation, New Delhi, India.

Knott, J.M., and Lipscomb, S.W., 1983, Sediment discharge data for selected

-61-

sites in the Susitna River Basin, Alaska, 1981-82: U.S. Geological Survey Open-File Report 83-870, 45 p.

Lamke, R.D., Still, P.J., Bigelow, B.B., Seitz, H.R., and Vaill, J.E., 1983, Water resources data, Alaska water year 1982: U.S. Geological Survey Water-Data Report AK-82-1, 363 p.

Leopold, L.B., Wolman, M.G., and ~1iller, J.P., 1964, Fluvial Processes In Geomorphology: W.H. Freeman and Company, San Francisco, California, 522 p.

Nakamura, K., Jacob, K.H., and Davis, J.N., 1977, Volcanoes as possible indicators of tectonic orientation - Aleutians and Alaska: Pageoph 115, p. 87-112.

Polubarinova-Kochina, P.Ya., 1939, On the continuity of the velocity hodograph in plane steady motion of ground water: DAN 24(4) (Russian).

Reeder, J.W. 1984, An analysis of fault and volcanic dike orientations for the Makushin Volcano region of the Aleutian arc, Proceedings of the International Symposium on Recent Crustal Movements of the Pacific Region: held February 9-14, 1984 at Victoria University, Wellington, New Zealand, Royal Society of New Zealand Bulletin, in press.

Selkregg, L.L., ed., 1974-77, Alaska Regional Profiles -- Southwestern Region: University of Alaska Arctic Environmental Information and Data Center, 313 p.

Waldron, H.H., 1961, Geologic reconnaissance of Frosty Peak volcano and vicinity, Alaska: U.S. Geological Survey Bulletin 1028-1, p. 677-708.

-62-

Appendix A

Discharge measurement notes for Delta Creek and the Clear Water Tributary of Delta Creek

-63-

Appendix A-1

5 tat e 0 f A I a s ka Dept. of Natural Resources Div. of Geological & Geophysical Surveys

jJ ,.5 C • M .... N ... ___________ _

WATER RESOURCE INVESTIGATIONS Comp. by _____________ _

DISCHARGE MEASUREMENT NOTES Chrd..d by ___________ _

Sla. No __ ._. ________ .. __ _

i'(lf~ &. ~( r.;'J' (!'c,;~ (t:tr /lIP. /!-~ ~,..:z:.-,....) Date __ ~_~.?_~ _______ . 19J~l Party _::--:: __ (rE.-?.f/?: ___ ! __ ~:_~_t~~ __ "!!~h_~_ ... __ Width ____________ Are. ____________ Vel. ___ . ____ C. H. ______ .___ DiKh. ____ . _______ . ___ _

Method __________ No. OWl. ____________ C. H. chang. ____ . _______ in ________ hn. Su.p. ______ _

Method coef. ___ ._____ Hor .ngle cod. _~. ____ Su.p. cod. __________ Meter No. ------ _________ .

GAGE READINGS Typ" of meter ._f!.!_r~ __ /!../l._r:'.~_t~_~ __ __ - Ti~e [=-=-;~-ecoTder! In,jd~ Outside

____________________________ ..1 __________ -- _______ _

~-:::::::- -:~:::::~: ::~~::::~:I:::::::::: ::::::::----------- ---------- ---------1---------- ---------.

:::::::::r:::::::: :-::::::-- :-::::::-. :::::::-i ,

::: .-----i~I=I~1 Weighted M. G. H··--f--- 1 __ '_1-· --.--G. H. ('orTl"'Ction -·--l---- --.~-l---. ______ . ___ _ COlT"" M G. H.! ! 1

Date rated ______________ . ______ . for rod. other.

Meter ___________ . ____ . ft. above oottom of weight.

Spin before meas . .L~3.fi:'_~ after L'~_~. Meas. plots ____ ';( diff. nom rating ______ _

~able. ICe, boat. upstr_. downstr .. side

bridge _.

gage. and.

. ___ feel mile. above, below

Ch,.ck-bar. found ____ . ____ __

chang..d to '. at

Corr!"Ct _ _ __ .

Lntl, obtain..d

Me.h'<fTtent rated excellent (2<;C) good (5~:C) air {8% . , (o"" Bo/c). k.ed on following

conditions: Cross section -t~~5.rY--Ji;n-~· G/:-i!;~~r-~~~':'i!'"I-~::r_-_~~~::_:::~:_::_:_:-:~:::_-_: _::-:--- .... ----___ ~_~a:her -fp:f~7-'~: __ -~~J~~~-~~:~~~:~ G~e ____________________________________________ .. ___________ . ___________ W.ter _______ °f@ _______ _

u _____________________________ Record felll<lved . , ___ .. ______ .________ Intale flu.~d ':-______________ _

Observe!' __ . __ . _______________________________________________ . ____ . ____ . _____ ... _________________________ _

C. H. of lao flow . . ft.

S 168 _ ............. "C-." ~ ... ~~ _____ 0.-."

Appendix A-1

.0 .10 .to .8\1 .60 .60 .70 .75

Ri ... ·rat-

~ Diol. ,J: T_ VELOCITY Adjust""

.~ Rno. far 1-. fn.m Width Otpth Jl oft.. in M ... n .,..k 01 Asea O;'Ch .... < initial

tiono -. At m Ya'""

<ill! point and> paiat tical .~--. ----

1',1 I II' ,,~ () L f 1". V ~.~ 1&'" ti liM) I~,' YS; --

-Li, f1 , (117 .~-~ ,t /(i /7 , ) 'I> , ~ 'I~ 7«,.." ,§~ , /96

b.t) I, C·t' ,7$- ,6 11/ 'f£) , 5'6~ ,>6~ . 7~- .'I~'I

7,/J /.00 .~() ,t 20 'f'/ /.01 /, h ,f? ,90 7 g',f) I,v() 1,1 (; 16 'Iv ;;6 I,~-e I,>~. l,IlJ /,7~~

f{,(} j.t/O I, 'It· rb to tl ZIt 2. It I, '-If-J 3. (J2,/

It,!! I,r-( 1.1~ ,/ to !?-3 .z. '17 2.'f9 /,71/ '1.23.3

II ,77 2,0 ,t Ie ~;,- ;2. 'to ;Z, 'Iti I,~-b 3.6~t> i----'

II,S' .5/' 2.{; ~- 6& -~ 2.27 2.Z7 /, I) () 2.27 ~ j--_. .- _. ~-

12.0 .'SIJ 2.0 6 ceo II 2.cp~ .2,~~ /.00 2.~g- . ~ -_.- --

12.5" ,§"i/ 2.0 ,e fO §t 3,o~ l~2 /,eo ~.().<.

13.0 ,7tJ I.go ,t 1(;0 S-~ ~. 77 3.77 (J.90 j.373 - -.

13.~;- ,'7'0 /.ctO.t J~() 5"t }.'ltJ J.Yp 0.7U 3.>/tJ ~----'---

. /if.O ~S-O /.<i§ ,6 11)0 >6 J.9p J,9~ v.~25 3. 6O?J -" II Y.> ,._,=c /.7; .1 IN) tV 3 i;; J.Y2 {),~lS- :<.7tJ'

=--t!§,~,'~O I. 7,.1 SO '--0 iz·'; 2.'2 ~,~J> ~.~sS-

~£.~ _./~ 1.60 .{ It) ~3 :<.Y~ 2.'ff u/60{) I, 'i7.? ----

16,0 ,"70 1.70 ,6 60 §'/ ~.'1r 2.,/'/ C,600 I, '1£ 'I /t.!?- ,~-o 1.'10 ,t b{> '.1/ ;;.53 ~.Sj ().71Pt) /,771 ---f-

lZ.f~_ .~~ ~.~S~_L'6() 72 ).J! J.Jl t;, t l!> 2./0{

_ 1/7,~i'5'P !'!.7 .t 8 0 t~ 2.!>8 2.~ O.7l.S I. tj 7/ Ilj' .7~ j·20 ,1 to '?-5'f;:.'10 .2.'1tJ ,70012,/60

-... "'7 II. o-;t-/. b ,( lo S:-S 22712.27 /, Of). 2.27---

-'12l--'~s-t? .6 2'0-- ~-f,- ~~7i'2 --.~ to To.-yt-~-~Tni,l~ Ii? ,';;W~,'d~nf/l:~O ~ -T- --' --I' '3"1,/,2--1---- --1 - t--1

-r--1--~F-TT- -- - --1-·-- --__ . __ J__ _ ___ ___ .. __ . __ =r .0 .\0 .20 .3~ .40 .50 .60 .70 .75

.SO

.to

.12

.14

.95

.97

.98

.tt

1.00

."

.IS

.97

.9£

.14

.'2

.9!I

Appendix A-2

S tat e 0 f A J as ka Dept. of Natural Resourc~s Div. of Geological & Geophysical Surveys

Me ... No. _ ~_~._?:.~_!_.

WATER RESOURCE INVESTIGATIONS Compo ~Jo1:f _____ _

DISCHARGE MEASUREMENT NOTES Ch«ked by ____________ _

~;:;(~:::~~~>:;!.:it-~h-:---"·;}:i.¥_'7/}-pRt!-:'-!-;(;;~{;id~;..f~~(: ~ Date _Jl.Mj~_.1.,.t . _______ • 19_'i:.{ Party --,?-&~dl~.-------------------.·---------------------Width ____________ Area ____________ Vel. ________ G. H .. ___________ Dilch. __________________ _

Mtthod __________ No. IcC!. ____________ G. H. change ____________ in ________ hn. Suap. ______ _

Method coeE. __________ Hor. angle cod. ____ Susp. coeE. __________ Meter No. _______________ . ------------"-------, Typ" of meter __ !!:!._~_t' ___ ,,!'._"":'.e._~~_'":. __ ._ ~ ______ G ... GE_R_E~!N_G_S'___.____--

Time I I Rec.order! Insidt Outside ===1==-[== = ~~~~:::~:: :::::~:::: ::::::::::1:::::::::: ::::~:::-: ---------- ---------- ._--------'---------- ---------.

:~~::::::: i: ::::~ ~~~: I. ::: ::: ~:: c::::::: ::~ _::::: I . I ------ --- -'. -- -- -----1- ----- --_. I .• -- - --- - - • - - --- ---

I i I ---.- -----!- -- --- -. --i- -------- -;- -- -- --: - ----. -- ---

Date rated _______ . ___ ._. for rod. other.

Meter . _______________ . ft. above bottom of weight.

" .. ' -Spin before meas. l._,(p.s_~__ after l.~!>.'~c.

Mea,. plot, ____ "-; diff. from rating _. __________ _

Gable. ice. boat. up,tr .. downstr .. side

bridge ________________ feet. mil.. above. below

gage. and ... _. ______ . __

Check-bar, found . _____ ._ ..

changed to _._

Correct.

Ltvel! obtained .. _

. at

---~ .=---, Measurer:-..nt rated excellent (2(,~). good (j%). fair (8%). ~~~.r'based on following

condition!: Cross .. etion _f?~c.!: __ J:/~~~~~_~_~_"'_t!..!·_:.:f-::.~-~----!:!..*:-'"'--~~!-~ .. /- arr-"ss ">C--L-c-"""

Flow _____ !lc5~ __ _ r:~I!'.~ ___ ':""_ __ ___ __________ Weather __ If.~.~,!~ __ ~- .E.~J~:T- -- -- -- ---------Other _______________ ______ __ ____ __ __ _ ___ _ _ _______ _ __ _ _ _ _____ _________ Air ______ . ____ 0 f@ _______ _

Case --------- ------- ----- --- ----- --- --- --- --- -- -. ------- -- --- ----- ---- --.- Water __ . __ . __ of@. _______ _ U

Record removed _____________________ _ Intake Au,h.,d L_. ____________ _

Ob~rver ________________________________________ . _. ____________________________ . __________________________ _

----- ----- --- -- ---- -- -- -- ---- ---- _. ----- - --

/~' .. // Control _____ ~ ___ ~·(J_r __ ,r.:.L.,.. ____ _________ . ______ . _. ___ . ______________ . _____ . ___ . _ -_. ___ . -- _______ -____ _

RernarIY ~ _________ . __________________ .

G. H. of ,ero flow __ 0 ________________ _ _ ____ . _. __ . __ ft.

S-7b8 .J __ O".L"." cc ... ·.<'0 .... _"._ .., ...

.0 .10 .zo .341

Appendix A-2

.50 River at-

.611· .70 .75

Appendix A-3

State of Alaska x:. Dept. of Natural Resources Div. of Geological & Geophysical Surveys

Meu No, _t!~'~£_! WATER RESOURCE INVESTIGATIONS Comp. by _~;;:~ ___ _

DISCHARGE MEASUREMENT NOTES Chechd by ____________ _

s .. 0;,;Eii~~(·, Yi?"'··R,)i~/:J···elf!4f,!-(/~<"d Date __ , __________ , _____ " ___ • 19___ ___ Party _" ________________________________________________________ _

Width ____________ Area ____________ Vd, _______ G, H ____________ Di6ch. __________________ _

Melhod _________ No, 'ees. ____________ G, H. change ____________ in ________ hrs. Su'p. ______ _

_ M_f_th_o_d_c_o_d_. _--_-_--_--_--_._H_or_, _a_n!!::.,.le_co_t_f._'_-,--- Su.!), wef. ' __________ Meter No. ________ ,. _____ . _, ____ , __ C~C~E_A_D_I~G_'_S_~__ Typ" if meter __ .!L~·r.~ ____ R.~_"':',~ ____ ~_'- _ _ ~~~_ , __ ~_:_Re(.order !_!naid~ ~~~__ Datt rat~d _______________________ for rod, oth~r.

::: .. ::: I::::: I ::::::::. ::: .:..... ~::·~ro~=~·. L' ~;;;";. '::::;201;::,

------"-- ---------T---------I--------- ---------- Meas, plots ---_ % diff. fr~m raling -- __________ _

::j:~]:~::i •••.•••••. ~b1 .. i~ ~:'f~:·:;,.d:::::~~~ I I I !:age, and ----------, ----- ----------------

--- --- ---[---- -----f ,--::-r -::-: _: ::-:: ::::: Check-bar. found -- - -- -- ---

"

- - changed to __________ ~ _______ at W.igh,.d M C. H. __ " "_ •. __ , ___ --'-~

G, H, co,,.,,,on------i--- !_~ ______ _

Con-tel M, G, H ____ ,, ___ 1 ___ _

Measurement rated excellent (2 %), good (5 '7~. air (8 %), ,'PO?! ~o';~r 8 %),' ~ on following

d" "C. . f( I c.k y p ~'-~'~--""'" /~_---con ,lion, rO@'Z~--:.EC/[--Ci-~~-------------------c-=---------'

~::r -_ :::_ :~~_~~~~~~~~~~~~~~~~ ___ : ,-~-. ,- ,--' -----~ __ ~~a:~~T __ ~~~--._-_:~ -_-~-_-_~~~~~~~~~ Gillie _________________________________ " ___________________ ... ___________ " _ W .t~ _______ 0 F@ _______ _

u _ _ _ __ __ _______ _______ _________ Record r • ..,oved ___ ,____ _ ___________ __ Intal« Ru,h~d L ___ , __________ _

Obaerv"," -- - - -- -- ---- --- --- - ------ - -" - ------ - -- -- --- ---, -- --,--- --.7-- ---- --- -----, ------ ---' ----- -------

, ~:~~;~~~~;f~i~~I~~~~;:~1f~ G, H. of WU flow _J: p.. __ ~_o:_;;!~,~,/-,,~?'-~/ ft. ;.; ~ ~-'lc!'..e~~ • /

'.c_ ~,c. r"~"z..// ~ l't" r ~ /1::--9,7 -'7":..e /'-::-:~."~~ ",;,;,:-:-.~,;;-;. I./,~/+ v • 2:.:/' C::'f S2168G-Y /1."<4J .----/_, tlltf -::;.CO~~ -.r~

.0 .10 .~ .341

W;Jth I 1~ Diot. ,-" ."6-

from > u

i:i iDitial Depth Aj ~ point

q/ tJ.>- (/0 J

f/) /. dO o.!F .6 I

1/ /,PO p,t~ .6 I

!2 IJ.75 tJ.7p ,6 1.2.~ U. ';J-c- ~. 9";'- ,6

V.lit 13.e '. I) 0 ·6 - r---- .. - f----\---. i ;.:;;- t/.~{) )./0 ,t

- _._-- 1----~-

I tJ.o v'. 50 o 9() ·6 - -_ ... - c---- -,--'

/ '"".:7 o.t;u /.J() ,6 - f-;5-o-I~. TLJ /,~ 0 .6

1-- • - .... -~--.. '---

'5" §.5'0 !I. 0> .6 -

'~, C~E70 O. 9~- .t i.5> ,IJ.'7"{, I, 05 .6

~

'7~O-~.~O /.1 t/ ,6 - ~- --I---0 I 7. ~- tJ.7"v

+-O.tD ,6

!p,O (),§l) O.7~ ,6 - 1-----_.

!~.7- 0. '7t tJ,90 It If,o ~.§o 1J.90 t If. ~- IJ. '7-0 it?, SO ,6

20.fJ 0,7'i [I; '17 ,t 21.0 1.00 ~. '17' ,6

22.0 l.tlO ~,J~ ,t 2ro /,00 0, YO .(

2 'f. 0 t.'SO a."§ ,6 2'11 IJ. :f/ -

.0 .10 .20 .30

Appendix A-3

Rev· aIu-t;"'"

.50 Rive!" at-

.60 .70

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