Evaluation of Bank Storage 

Along the Columbia River 

Between Richland and 

China Bar, Washington

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1539-1

Prepared on behalf of the U.S. Atomic 

Energy Commission and published with 

the permission of the Commission

Evaluation of Bank Storage 

Along the Columbia River 

Between Richland and 

China Bar, Washington

By R. C. NEWCOMB and S. G. BROWN

CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1539-1

Prepared on behalf of the U.S. Atomic 

Energy Commission and published with 

the permission of the Commission

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1961
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY 

« Thomas B, Nolan, Director

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington 25, D.C. - Price 15 cents (paper cover)
CONTENTS

Page

Abstract_________________________________________________________ 1-1

Introduction______._______________________________________________ 1

Purpose of the study-_________________________________________ 1

Location and characteristics of the area________________________ 2

General geologic characteristics___--__-____----______-__---________ 4

The bank-storage effect_______________________________^____________ 5

Zone of influence of river stage__________________________________ 5

Manner of occurrence___-_-_-_-_______________----___-_____-___ 6

Geohydrologic data____________________________________________ 9

Estimate of the magnitude of the bank stor&ge________________________ 11

Projection of the derived values along the main stem of the Columbia River. 12

Summary. ___________________________«_________________________ 12

ILLUSTRATIONS

Page 

FIGURE 1. Index map___________________________________________ 1-2

2. Map showing the location of the observed bank-storage effect 

along the Columbia River on the Hanford Reservation, 

Wash________________________________ 3

3. Hydrographs of three wells compared with the hydrograph of

the Columbia River at Richland__________-_____________ 6

4. Hydrographs of two wells compared with the hydrograph of

the Columbia River near old White Bluffs townsite.______ 7

5. Hydrographs of wells compared with the hydrograph of the

Columbia River near Coyote Rapids.___________________ 8

m

585227 61

CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

EVALUATION OF BANK STORAGE ALONG THE COLUMBIA

RIVER BETWEEN RICHLAND AND CHINA BAR,

WASHINGTON

By R. C. NEWCOMB and S. G. BROWN

ABSTRACT

During hydrologic investigations at the Hanford Reservation of the Atomic 

Energy Commission, the bank-storage effect was noted. The bank storage is 

indicated by the uniform rise and decline of ground-water levels in agreement 

with the annual flood flow in the river. The rise in water levels is observed 

in a 100-square-mile zone along 60 miles of the right bank of the Columbia 

River. The amount of water placed in bank storage by the high stages of 

the average annual flood is estimated to be about 170,000 acre-feet. Most of 

this water is removed directly from the river channel, whereas only about 1 

percent is ground water that is prevented from entering the river. During a 

45-day rise in the river, water from the river may infiltrate to the groundwater body at an average rate of about 3,700 acre-feet per day. During the receding stages, an average of about 1,000 acre-feet of this storage returns to the 

river per day. The bank storage along this reach of the river amounts to 

about two-thirds the volume placed in channel storage by the river's rise to 

the annual flood peak.

Because of known but unevaluated differences in geologic conditions along 

other parts of the main stem of the Columbia River, the values for bank storage in this 50-mile area must be weighted properly before they are projected 

elsewhere along the stream.

INTRODUCTION

PURPOSE OF THE STUDY

Few evaluations of bank storage are recorded in the literature. 

Even the definition of bank storage is uncertain. In this work the 

writers consider bank storage to include all the surface water that 

seeps through the bed (and banks) of the river into the rocks underlying the valley, plus the ground water that is prevented from entering the stream during the storage period.

The U.S. Geological Survey has been doing hydrologic and geologic work in cooperation with the Atomic Energy Commission and 

the companies operating the Hanford Plant near Bichland, Wash. 

Data collected during this work permits an estimate of the bank

1-1
1-2 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

storage and its effect on the flow of the river along one segment of 

the Columbia Eiver.

LOCATION AND CHARACTERISTICS OF THE AREA

The Columbia River flows through the Pasco Basin in a locally 

broadened segment of its characteristic gorge. This locally broadened segment includes 90 miles of the river between its passages 

through mountain ridges in Sentinel and Wallula Gaps (fig. 1) Its

\ i. Sentinel Gap

U Priestly

Yak.ma") Rapid

Daim

FIGURE 1. Index map showing the location of the area covered by figure 2.

topography is a diverse mixture of flood plains, terraces, river bluffs, 

and low plateaus with some mountain ridges (fig. 2). McNary Dam, 

15 miles downstream from Wallula Gap and 42, miles downstream 

from Eichland, impounds the river to an altitude of about 340 feet, 

and the slack water of the reservoir reaches upstream about halfway 

through the Pasco Basin to a point several miles above Eichland. 

The Priest Eapids damsite lies at the north foot of Umtanum 

Eidge, about 4 miles upstream from China Bar which is at the northwest edge of the Hanford Eeservation. Thus, the reach of river 

treated in this report extends from the slack water of the McNary 

Eeservoir to the bedrock channel near Priest Eapids. In this 50- 

mile segment the river descends evenly from an average low-water 

level of about 392 feet at China Bar to the 340-foot level of the 

McNary Eeservoir, except for a drop of about 8 feet in the ^-niile 

length of Coyote Eapids. The low-water level at Eichland prior 

to closure of McNary Dam was about 326 feet, as shown on figure 3.
BANK STORAGE, HIGHLAND TO CHINA BAR, WASH. 1-3

R. 25 E. R. 26 E. R. 27 E. R. 28 E.

3Q1 !"" (^ Gaging station 

China Bar 11D1

FIGURE 2. JMap showing the location of the observation wells and the zone of observed 

bank-storage effect along the Columbia River between Rlchland and China Bar on the 

Hanford Reservation, Wash*
1-4 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

The Pasco-Kennewick area, just downstream, from Richland, and 

the Hanford Reservation, upstream from Richland, are two large 

areas of terraced land. The altitudes of the terraces range from 

about 340 feet at reservoir level to about 700 feet on the high terraces in the northwestern part of the Hanford Reservation.

GENERAL GEOLOGIC CHARACTERISTICS

The Columbia River basalt of Miocene and Pliocene(?) age is a 

layered sequence of lava flows several thousand feet thick. It forms 

the bedrock of the area and is exposed in the ridges that bound the 

Pasco Basin and in a few knobs, such as Gable Mountain and Gable 

Butte, which project above terrace lands. The basalt is permeable 

mainly along the contact zones between some of the lava flows. The 

overall permeability of the basalt is much less than that of the coarsegrained members of the unconsolidated deposits which overlie it.

In the downwarped syncline beneath the Pasco Basin the basalt is 

overlain by the Ringold formation, which is a lacustrine deposit composed predominantly of silt. The Ringold also contains much sand, 

some clay, and one prominent member of weakly consolidated gravel 

and sand that commonly is called "the conglomerate." The Ringold 

formation in places lies on the basalt at an altitude in general near 

sea level and extends up to about 1,000 feet. The 600 feet of strata 

exposed above the level of the Columbia River are horizontal or 

nearly horizontal, but some of the lowest strata, now below river 

level at The White Bluffs, may have been folded and tilted in the 

last deformation of the basalt bedrock. The conglomerate member of 

the Ringold formation consists of gravel and sand and was deposited 

in a trainlike band about 10 miles wide across the lacustrine basin of 

deposition from near Sentinel Gap to Wallula Gap. The member 

is about 160 feet thick; throughout much of the Pasco Basin it lies 

between altitudes of 290 and 450 feet. The conglomerate is not 

present in The White Bluffs northward from Ringold Flat to 

Wahluke.

A mantle of glaciofluviatile and fluviatile deposits overlies the 

eroded surface of the Ringold formation throughout the lowlands 

between The White Bluffs and the several mountain-sized ridges, 

collectively known as the Yakima Ridges, and throughout the PascoKennewick area southeastward to Wallula Gap. The deposits range 

in thickness from 20 to 100 feet and consist largely of gravel but 

contain some sand beds. The gravel is mostly of granule and pebble 

size but in places includes many cobbles and some boulders. In a 

few places it includes thick beds consisting almost entirely of boulders. 

In other places, especially in the upper part of the deposit along
BANK STORAGE, HIGHLAND TO CHINA BAR, WASH. 1-5

embayments in the mountain fronts and in areas sheltered from 

erosion, silt lenses and other fine-grained deposits predominate. The 

glaciofluviatile and fluviatile deposits occur as a deep mantle upward 

from the river level to an altitude of about 700 feet and as a thinner 

mantle to about 1,150 feet. They lie above the low-water level of 

the riverbed in all but a few places and above the natural level of 

the water table in large parts of the reservation and the PascoKennewick area.

The most important aspect of the geology as related to the problem 

of bank storage is the position of the irregular but nearly horizontal 

contact between the Eingold formation and the overlying more permeable glaciofluviatile and fluviatile deposits. Along the right bank 

of the river near North Eichland this contact lies at an altitude of 

about 340 feet (very near to the average level of the reservoir) and 

about 10 to 20 feet above the average river level along most of the 

right bank upstream from North Eichland to China Bar. In the 

vicinity of the old Hanford townsite and the broad bench just downstream from China Bar, the contact lies below the average river level. 

The ground-water flow toward the river at low-water stages is largely 

in the Eingold formation, but the bank storage occupies a vertical 

zone lying both in the Eingold formation and in the glaciofluviatile 

deposits.

THE BANK-STORAGE EFFECT

ZONE OF INFLUENCE OF RIVER STAGE

Water levels in wells within a zone along about 50 miles of the right 

bank of the Columbia fluctuate with the stage of the river. They 

fluctuate in marked contrast with water levels in wells in other parts 

of the reservation, where seasonal changes in water level are insignificant. In general, fluctuations are greatest near the river and decrease 

in magnitude with distance from the river. The extent of the zone in 

which ground-water levels fluctuate in response to river stages is shown 

in figure 2. The observed water-table fluctuations range in height 

from 2.9 to 19.3 feet (figs. 3-5) and average 9.4 feet over an area of 

about 100 square miles.

The wells whose hydrographs are shown in figures 3-5 are numbered 

according to the following system: The township and range form the 

first two numerals and are separated by a slash; the section gives the 

third numeral. The letter refers to the 40-acre tract by a successive 

order in which A is the northeastern, D is the northwestern, E is 

SW%NW*4, M is NW%SW*4, N is the southwestern, and E is the 

southeastern. The letters I and O are omitted. The final numeral 

gives the order in which wells were numbered in that 40-acre tract.

585227 61 2
1-6 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

Altitude of measuring point 

395.15ft

JFMAMJJASONDJFMAMJJASONDJFMAMJJASOND 

1950 1951 1952

3. Hydrographs of three wells in the southeastern part of the Hanford Reservation compared with the hydrograph of the Columbia Kiver at Kichland, Wash.

MANNEB OE OCCUBBENCE

The bank storage is a direct result of the seasonal fluctuations of 

river stage. When the river is at low stage, the water table lies mainly 

within the Eingold formation and slopes about 5 feet per mile toward 

the river. At that time, the flow of ground water into the river is 

small. As the river begins to rise in flood, at the start of the average 

45-day period of increasing flow, the gradient of the water table 

toward the river is lessened and ground-water flow into the river decreases. As the river continues to rise, the gradient of the water table 

near the river is reversed and, by direct contribution of water through 

the bed and banks, the stream feeds the ground-water reservoir. The 

water is stored in the ground-water reservoir beneath land adjacent to 

the river, thus depleting the flow of the river slightly during periods 

of rising stage. After the stage of the river has peaked and begun to 

decline, the gradient again is reversed, and the bank-stored ground
I I I I I I I I I I I

-365-

Altitude of measuring point 434.23 ft 

Distance to river 11,200 ft

13/27-17J1

 360^

LU 

O

ca

en

UJ

o

UJ

Q

ID 

I13/27-21L1

Altitude of measuring point 414.20 ft 

Distance to river 10,500 ft

 365-

-385-

Columbia River near old White Bluffs townsite

 375-

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 i i i i I 

JFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJ

1949 1950 1951 

FIGURE 4. Hydrograph of two wells northeast of Gable Mountain compared with 

White Bluffs townsite, Washington
-l405| | | |

13/25-11D1

-400-

Altitude of measuring point 416.91 ft .

Distance"1^ river 1300ft --''

395 "405

-400-

13/25-12P1

Altitude of measuring point 498 ft__ 

Distance to, river 6100 ft ,--'

- 395 

7400" Altitude of measuring point 540 ft^ 

Distance to river 9300 ft,--''

13/26-18C1

_

. 405*

Altitude of measuring point 433 ft 

Distance to'river 1000 ft

-400-

-395-

390

405 / \Columbia River near (three 

fourths of a mile above) 

Coyote Rapids

r395

13/25-3Q1

i i i i i i i i i

JFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFM

1949 1950 1951 

FIGURE 5. OETydrographs of wells south and west of Coyote Rapids in 

Reservation compared with the hydrograph of the Columbia R
BANK STORAGE, HIGHLAND TO CHINA BAR, WASH. 1-9

water percolates to the river until the normal average gradient toward 

the river is restored. During this period of draining, water levels 

within the bank-storage zone along the river decline for about 150 to 

180 days.

This percolation into the bed and its complete direct return characterizes the bank-storage zone in all but a few places. The area inside the river bend near the old White Bluffs townsite has one variation from the normal pattern of direct-return percolation. The 

influent percolation along the upstream side of this large river bend 

can raise the water table sufficiently to cause some of the water to 

percolate eastward across the bend, escaping the zone of direct return 

and entering the river above the old Hanf ord townsite.

Radioactive tracers demonstrate that the bank-stored water has 

some downstream movement and that its return to the river is slightly 

oblique downstream rather than normal to the river's edge. However, this detail does not diminish the general directness of the infiltration and return of the bank storage.

GEQHYDBOLOGIC DATA

Bank storage is confined to a mixed zone of conglomerate of the 

Ringold formation and the overlying glaciofluviatile and fluviatile 

deposits, except in a few places such as part of the old White Bluffs 

townsite area, which lies northeast of the train of conglomerate in 

the Ringold. There, during the high levels of ground water, the 

materials saturated are the silt and sand of the Ringold and the 

overlying glaciofluviatile and fluviatile deposits.

From several pumping tests and computations, the permeability 

of the conglomerate of the Ringold formation has been determined 

to range from 100 to 800 gpd (gallons per day) per square foot. 

As determined in two places on the reservation, its effective porosity 

is 11 percent.

The glaciofluviatile and fluviatile deposits are much more permeable 

than the conglomerate of the Ringold formation. Aquifer tests indicate that the permeability of these deposits ranges from about 16,000 

to 60,000 gpd per square foot. Their effective porosity is about 20 percent. As about two-thirds of the water in bank storage is in the conglomerate of the Ringold formation (average permeability about 

450 gpd per square foot) and the other third is in the overlying 

glaciofluviatile and fluviatile deposits (average permeability about 

38,000 gpd per square foot), an overall average permeability of about 

13,000 gpd per square foot can be assumed for the wedge of permeable materials that are saturated and dewatered during each an-
1-10 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

rnial flood cycle. In a similar manner, an average effective porosity 

of about 14 percent may be assumed for these materials.

By the end of the drain-back period, the water table has declined 

until it lies in the Ringold formation throughout most of the bankstorage zone. Hence, in computing an estimate of the normal amount 

of ground water percolating to the river during the low-water part 

of the year when there is little or no bank-storage contribution, the 

average permeability of the Kingold formation (450 gpd per square 

foot) is used. Computations employing Darcy's law indicate that 

the normal ground-water contribution to river flow at low-water 

stages would be equal to less than 1 percent of the water that accumulates in bank storage during the average 45-day period of rise 

in river stage.

The hydrographs given in figures 3 to 5 are typical of those of the 

observation wells in the zone of bank storage. Water levels of three 

wells north of North Eichland rose and fell in close agreement with 

the level of the river, as observed at Eichland (fig. 3). The average 

amplitude of the annual bank-storage rise decreases from about 16 

feet in the well 250 feet from the river to about 12 feet in the well 

4,000 feet from the river. Changes in ground-water levels lag slightly 

less than 1 week behind changes in river level, and the lag is only 

slightly greater in the well at 4,000 feet than in the well only 250 feet 

from the river.

The special type of fluctuation induced in ground-water levels near 

the inland edge of the bank-storage zone north of Gable Mountain 

is illustrated by the hydrographs of two wells in figure 4. The hydrographs show that the peak levels of ground water follow about 2 

months behind those of the river nearby and that ground water rises 

to peak levels and declines to low levels at a slower rate than the river. 

These wells lie near the land edge of the area in which ground water 

moves across the circuitous bend at old White Bluffs. The length 

of the flood-time fluctuation of the water levels in these wells may 

represent ground water transmitted from the northwest rather than 

entirely bank storage.

In figure 5 the hydrographs of five wells show a greater lag and 

a decreasing amplitude of the annual bank-storage wave with progressively greater distance from the river. They also show a lesser 

altitude of the crest of that wave in the wells farther downstream. 

These hydrographs illustrate that the observed fluctuations are not 

all uniform and consistent; irregular heights and times are observed 

in the ground water at some wells within the bank-storage zone.
BANK STORAGE, HIGHLAND TO CHINA BAR, WASH. 1-11

ESTIMATE OF THE MAGNITUDE OF THE BANK

STORAGE

In the 100 square miles of the zone of observed bank-storage effect 

(fig. 2), the average observed fluctuation in water level is 9.4 feet, 

and the average effective porosity is 0.14. The volume of water in 

bank storage may be computed as follows:

Vs=Ahp 

where:

Vs=volume of water in storage,

A area of the zone of observed bank-storage effect,

h average range of water-level fluctuations, and

p=average effective porosity of material newly saturated

or drained

Fs= (100X640) X (9.4) X (0.14) 

Vs=84,000 acre-feet

The assumption that the conditions on the left bank are equal 

would indicate that the bank storage between North Eichland and 

the bedrock reaches of the river near Priest Eapids at the time of 

the average flood peak is about 170,000 acre-feet of water. However, 

this assumption is not entirely true because the glaciofluviatile and 

fluvial deposits lie at higher levels along much of the left bank.

The bank storage occupies the thin wedge between the inwardsloping preflood water table and the outward-sloping water table at 

the flood peak. For a river rise of 20 feet this bank storage should 

contain about 99 percent, or 168,000 acre-feet of water, contributed 

by the river and about 1 percent of ground water whose normal movement toward the river is temporarily halted. The writers consider 

both types of water to be bank storage. If the 168,000 acre-feet of 

water is prorated over the 45-day rise to flood peak, the average 

diminution of the river at Eichland is about 3,700 acre-feet per day.

The actual average distance that the influent water penetrates the 

ground is much less than the width of the zone in which the water 

table rises. This actual penetration is in the range of hundreds of 

feet at a maximum. An approximate solution may be obtained for 

the question of how far from the river this 168,000 acre-feet of river 

water actually moves: The volume of water moving to bank storage 

may be divided by the area of the riverbed at the flow peak (taken 

as 50 miles long by 0.50 mile wide) divided by the effective porosity 

(0.14), and an average penetration of about 75 feet is indicated for 

the infiltrating water.

The seasonal low-water level in wells in this zone is reached 150 to 

180 days after the annual high; consequently, on the receding stage
1-12 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

bank storage may contribute an average of 1,000 acre-feet per day 

or about 500 cfs (cubic feet per second) to the flow of the river.

For comparison, the channel storage added by the flood rise in this 

same segment of the river can be estimated by assuming an average 

change in width from 14 to % mile during the 20-foot rise to flood 

peak. The resulting estimate of 240,000 acre-feet of channel storage 

is about 1.5 times the estimate for bank storage resulting from the 

same average annual flood.

PROJECTION OP THE DERIVED VALUES ALONG THE 

MAIN STEM OP THE COLUMBIA RIVER

Upstream from China Bar, the natural channel of the Columbia 

Kiver is on bedrock over much of its length to the Canadian border. 

The effective porosity and permeability of these rocks is less than 

that of the conglomerate member of the Kingold but is not known 

sufficiently to permit this type of an estimate of the bank storage. 

In places between China Bar and the Canadian border, glaciofluviatile 

-and fluviatile deposits as well as glacial deposits and Eecent alluvium 

are known to accept and discharge considerable bank storage; the 

bank storage may be large where these deposits border the river in 

reservoirs. The probability that water entered and withdrew from 

bank storage in amounts measurable at the gaging stations is indicated 

for certain years by a comparison of the discharge records at Bridgeport and Grand Coulee Dam, 165 and 220 river miles respectively, 

above China Bar. At the present time, however, estimates of bank 

storage at the Hanf ord Keservation would require at least large adaptive weighting to be applicable to other reaches of the main stem of 

the Columbia Eiver.

In recent years water-management agencies have attributed to bank 

storage some of the apparent losses and gains of water in certain segments of the river during particular changes in the river flow or 

river level. The filling of reservoirs behind hydroelectric-power 

dams has at times taken more inflowing water than the carefully 

measured reservoirs were expected to hold. Likewise, the lowering of 

the level in some reservoirs has yielded more water than their surface 

storage would indicate. The necessity for integration of bank 

storage into river-management operations is evident.

SUMMARY

During the annual flood-runoff cycle, the Columbia Eiver rises and 

falls about 20 to 30 feet, and the water level in wells along the river 

on the Hanf ord Eeservation rises and f alls in response to the changes
BANK STORAGE, HIGHLAND TO CHINA BAR, WASH. 1-13

in the river stage. The observed annual rise in ground-water levels 

averages about 9.4 feet beneath a riverbank zone, which averages 

10,000 feet in width and has an aggregate area of about 100 square 

miles on the right side of the Columbia Kiver.

The rise and fall of the water table indicates that throughout the 

zone adjoining the right bank of the river, in the reach from the 

bedrock channel near China Bar to the head of McNary Reservoir 

near Richland, there may be stored and released annually about 

85,000 acre-feet of water. About 99 percent of this water is believed 

to be diverted from the river and about 1 percent to be retarded 

ground water. A projection of this derivation to include the somewhat different left side of the river, with the storage averaged for 

a 45-day period of river rise, indicates that an average of about 3,700 

acre-feet of water per day is diverted directly from the river to bank 

storage during the average 45-day rise of the river to flood peak. 

The water returns to the river at an average rate of about 1,000 acrefeet per day during the 165-day period of the river's decline.

The bank storage is equal to about two-thirds of the water placed 

in channel storage by the average annual rise to flood peak. In the 

future, bank storage may need to be derived systematically and its 

effects on streamflow integrated into the management of the water 

resources of many rivers.

o