GEOLOGICAL SURVEY CIRCULAR 550 

Discharge in the lower 

Columbia River Basin, 

1928-65 

By Hollis M. Orem 

GEOLOGICAL SURVEY CIRCULAR 550 

Washington 1968 
United States Department of the Interior 

STEWART L. UDALL, Secretary 

Geological Survey 

William T. Pecora, Director 

Free on application to the U.S. Geological Survey, Washington, D.C. 20242 
Abstract ----------------------------------· 

Introduction -------------------------------· 

Purpose and scope ---------------------· 

Description of the study area -----------· 

Acknowledgments ----------------------· 

Estimation of discharge ----·----------------· 

Summation method ---------------------· 

Gaged areas -----------------------· 

Ungaged areas --------------·------· 

Precipitation and evaporation -------· 

Time of travel ---------------------· 

CONTENTS 

Page 

1 

1 

1 

1 

3 

3 

3 

3 

4 

4 

4 

Correlation method ---------------------· Major inflow segments ________ , _____ _ 

Precipitation, evaporation, and time 

of travel ------------------------· 

Adjusted monthly mean flows -----------· 

Accuracy of estimates -~----------------· Comparison of estimated and ·measured flows ------------------------ Comparison of estimates by correlation and summation methods -----· 

Known deficiencies in methods ------· 

References --------·----·--------------·------· 

ILLUSTRATIONS 

page 

5 

5 

6 

8 

9 

9 

9 

9 

10 

Page 

Figure 1. Map of lower Columbia River basin --------------------------------------------·-------· 2 

2. Correlation for inflow between The Dalles, Oregon, and Vancouver, Wash ----------------- 6 

3. Correlation for Willamette River at mouth ---·-------------------------------------------· 7 

4. Correlation for inflow below Vancouver, Wash -----------------------------------------· 8 

TABLES 

Page 

Table 1. Outline of summation method for estimating flow of Columbia River at mouth ,..---------· 13 

2. Comparison of estimated and measured flows-Columbia River at Vancouver, Wash _________ 14: 

3. Estimated "observed" flow8-'Columbia River at Vancouver, Wash ------------------·------·-- 15 

4. Estimated "adjusted" flows-Columbia River at Vancouver, Wash ----·--·-----------------· 16 

5. E:stimated "observed" flows-Willamette River at mouth --------------·-----------------·-· 17 

6. Estimated "adjusted" flows-Willamette River at mouth --------------------------------· 18 

7. gstimated "observed" flows-Columbia River at S.t. Helens, Oreg --·--------------·-------· 19 

8. Estimated "adjusted" flows-Columbia River at St. Helens, Oreg --------·--------·-----·---- 20 

9. E"Btimated "observed" flows-Columbia River at Longview, Wash -----------------------· 21 

10. Estimated "adjusted" flows-Columbia River at Longview, Wash ------------------------· 22 

11. Estimated "observed" flows-Columbia River at mouth ----------------------------------- 23 

12. Estimated "adjusted" flows--Columbia River at mouth ---------------------------------· 24 

m 

DISCHARGE IN THE LOWER COLUMBIA RIVER BASIN, 1928-65 

BY HOLLIS M. 0REM 

Abstract 

Estimates of monthly and annual mean discharge 

for five ungaged sites in the lower Columbia River 

are presented for water years 1928-65. These sites are 

Columbia River at Vancouver, Wash., Willamette 

River at mouth, Columbia River at St. Helens, Oreg., 

Columbia River at Longview, Wash., and Columbia 

River at mouth. Two tables of estimates are compiled 

for each site. One table lists estimates of "observed" 

flow, the flows that would be measured by a gaging 

station. The other table lists "adjusted" flows, the 

"observed" flows adjusted for storage changes in 

major reservoirs and for diversion at Grand Coulee 

Dam. 

Two methods are used in making these estimates. 

One method involves a detailed summation of flows 

from all gaged and ungaged areas, allowance for precipitation on and evaporation from the channel water 

surface, and adjustment of flow to allow for travel 

time from gaging stations at the Dalles, Oreg. 

(Columbia River main stem), and at Salem Oreg. 

(Willamette River). 

The other method is the same as the summation 

method except that flows from individual gaged and 

ungaged areas below The Dalles and Salem are not 

summed in detail. Instead, the entire drainage area 

below The Dalles is divided into three major inflow 

segments and the flow from each segment is obtained 

from a correlation with streams that are representative of the flow from that segment. 

Estimates of monthly mean flows are considered to 

be accurate within 2 or 3 percent. 

INTRODUCTION 

The need for historical streamflow data for 

the lower reaches of the Columbia and Willamette Rivers is heightened by prospects for 

increased industrialization in those areas and 

by water-quality standards that are being set. 

Because of tidal effects in the lower reaches 

of these streams, no continuous records have 

been collected there until the last few years 

and then, only on the Columbia River at Vancouver, Wash. Because actual historical 

streamflow data are lacking, the obvious alter1 

native is to estimate such records using the 

best available data. Throughout the Columbia 

River basin the Water Management Subcommittee of the Columbia Basin Inter-Agency 

Committee has used the period July 1f28 to 

June 1958 for planning purposes as this period 

includes the critical low-wa~r periods a~ well 

as high-water years such as 1948 and 195~. The 

estimates presented in this report includ ~ that 

period. 

PURPOSE AND SCOPE 

This report presents two tables of discharge 

estimates for each of five ungaged sites in the 

lower Columbia River basin for the period 

1928-65 (see tables 3-12 at end of this report). One table lists "observed" monthly 

mean discharge; that is, the flows that would 

have been measured at a gaging station at the 

site. The other table lists "adjusted" monthly 

streamflow, which is the "observed" flo"V adjusted for storage changes in major upstream 

reservoirs and for diversions at Grand Coulee 

Dam. The "adjusted" flows represent f, "noreservoir" condition. Because these runoff 

figures more nearly represent natural flmv conditions, they are convenient for studies involving different sets of reservoirs or operations. 

The report also describes methods ur~d to 

estimate these monthly and annual strean1flows 

at the four sites on the Columbia River below 

Bonneville Dam and for Willamette River at 

mouth. The four Columbia River sites are at 

Vancouver, Wash., below Lewis River at St. 

Helens, Oreg., below Cowlitz River at Longview, Wash., and at mouth. No attemr~ has 

been made to estimate daily flows. 

DESCRIPTION OF THE STUDY AREA 

The lower Columbia River basin as used in 

this report includes that part of the basin 
47" 

46° 

45° 

44° 

43° 

:<; 

~ 

~ 

() 

0 

() 

...... 

k, 

...... 

\.) 

~ 

Q.,. 

• Gaging station used also 

as index to correlate inflow in reach 

6 

Sites of estimated discharge 1. Columoia Ri11er at Vancouver 

2. Willamette River at mouth 

3. Columbia Ri11er at St. Helens 

4. · Columbia River at Long·view 

5. Columbia R1:ver at mouth 

Basin divide 

Drainage divide 

~ 

'~ 

0 50 MILES 

L-L-L-L-~~-----___j 

25 

Figure 1.-Map of lower Columbia River basin. 

2 
downstream from the gaging stations on 

Columbia River at the Dalles, Oreg., and on 

Willamette River at Salem, Oreg. (see fig. 1). 

The drainage area at the Dalles is about 237, 

000 square miles and the drainage area at the 

mouth of the Columbia River is about 258,000 

square miles. The incremental area between 

these points is, therefore, 21,000 square miles, 

lying almost entirely west of the Cascade 

Range. Only about 4,600 square miles of the 

area below the Dalles and Salem is ungaged, 

and about 400 square miles of that is river 

channel water surface or low sand islands 

which lie largely in the extreme lower reaches 

where the river becomes several miles wide. 

However, the water from the 21,000 square 

miles is an important part of the flow at the 

mouth of the Columbia River. Average runoff 

from this area is 3.62 cfs per sq mi (cubic feet 

per second per square mile) whereas average 

runoff from the area above The Dalles is only 

0.824 cfs per sq mi. 

Most of the study area is between 500 and 

5,000 feet elevation and is heavily forested; 

but some lower areas, such as the Willamette 

River valley, are largely under cultivation with 

interspersed forests. 

There is only one impoundment (Bonneville 

Dam) below The Dalles on the main stem of 

the Columbia River, but this is a Hrun-of-river" 

reservoir with inconsequential monthly storage 

changes. In determining "adjusted" monthly 

flows it was necessary to adjust for (1) storage 

changes in nine major reservoirs above The 

Dalles, (2) pumpage (diversions) at Grand 

Coulee Dam, and (3) storage changes in seven 

reservoirs above Salem in the Willamette 

River basin and three reservoirs in the Lewis 

River basin. 

ACKNOWLEDGMENTS 

The author is indebted to Vail Schermerhorn 

of the U.S. Weather Bureau, David M. Rockwood and Carlton Jencks of the Corps of Engineers, and William Haushild of the U.S. Geological Survey foJ'l information on time of 

travel used in routing flows. Basic data f.or 

gaged areas are from the Oregon and Washington district Offices of the U.S. Geological 

Survey. 

3 

ESTIMATION OF DISCHARGE 

Two methods were used for estbnating 

monthly mean flows at the five ungagoc sites. 

The first and basic method invplved summation 

of flows for all gaged areas with estimates .of 

flow for all ungaged areas (Orem, 1961). 

The second was a shortcut method tr.~t involved dividing the area between the Dalles, 

Oreg., and the mouth of the river intc three 

major segments and estimating the flow for 

each segment by correlation procedure:~. The 

second method was used for some of the early 

years before many of the gages were in~talled 

on intervening areas l>etween The Dall~s and 

the mouth of the river. 

SUMMATION METHOD 

The summation method consisted of starting with gaged flows of the Columbia River 

at the Dalles, Oreg., and adding tri"'•Itary 

flows as they entered the river. Table 1, which 

illustrates the method, is for the 15-year period 

covering water years 1943-57. The table was 

prepared about 1960 when average ftc w for 

that standard period was needed for Columbia 

River at Vancouver, Wash., and Columbia 

River at mouth. That table is shown in this 

report in preference to using a specific month 

as an example because (1) average values for 

ungaged areas were estimated in this table, 

and (2) the tabulation is for a 15-year period 

and, therefore, the computation is not complicated with travel-time adjustments. To estimate flows for individual months, travel-time 

adjustments are used when flow at the end of 

the month is materially different from fow at 

the beginning of the month. These adjustments 

will be explained in more detail later in the 

report. 

Gaged areas 

For most of the 1928-65 period streamflow records are available for all but abcnt 1.6 

percent of the Columbia River drainage area. 

This small ungaged area accounts for 4.6 percent of the flow at the mouth of the Col'lmbia 

River. The gaged areas are listed in u.ble 1. 

The "Remarks" column in the table inc.icates 

that even in the period 1943-57 there were a 

few months or years of missing record for 

several of the gaged areas and that flovr data 
for these short periods were estimated by correlation with records of a nearby stream. 

Ungaged areas 

Estimates of ungaged average inflow to the 

Columbia River for five areas are given in table 

1. Because the ungaged areas and flows are 

small compared to the flow of the Columbia 

River, estimates of monthly flow at the ungaged main-stem sites cannot be materially 

in error because of erroneous estimates of ungaged inflow. Nevertheless, con~iderable care 

and effort went into- these estimates. Average 

runoff rates for the areas were determined in 

terms of the average runoff rate for a nearby 

gaged area based on a runoff map developed 

by Hulsing and Kallio (1964) of the Geological 

Survey. Their map of isopleths pf runoff was 

developed from a st:.:dy of all records of discharge in Washington and Oregon and an 

isohyetal map (lines of equal precipitation) 

prepared by the Portland District, Corps of Engineers. 

Precipitation and evaporation 

Downstream from the gaging stations in 

Oregon at The Dalles and at Salem there are 

400 square miles of river channel and islands. 

Increments of flow were included for precipitation directly on this surface and decrements 

were included for evaporation from the surface. 

Because these components are relatively small 

and tend to cancel each other, they were included in the estimates of monthly flow for only 

the two lower ungaged sites. About half the 

400 square miles is upstream from the ungaged 

main-stem site below the Cowlitz River. Therefore, precipitation on and evaporation from 

the 400 square miles of water surface were 

taken into account f.or flow of Columbia River 

at mouth and from 200 square miles for Columbia River below Cowlitz River. Monthly flow 

increments were obtained by averaging the 

amount of precipitation recorded at Weather 

Bureau stations in Oregon at Bonneville, 

Salem, Portland, and Astoria and converting 

that average to equivalent cubic feet per 

second. Monthly flow decrements for evaporation were obtained using average monthly 

values derived from U.S. Weather Bureau 

Technical Papers 13 and 37 (U.S. Weather 

4 

Bureau, 1950, 1959). Paper 13 shows that annual evaporation averages 24 inches for the 

area downstream from The Dalles and Salem. 

Paper 37 indicates a distribution by months 

of this 24 inches on the basis of records for 

Seattle, Wash., the most repre~~ntative point 

for which year-round records are available. 

Time of travel 

When flow changed materially during the 

month, the estimates for the five ungaged sites 

required adjustment for time cf travel of the 

water. Adjustments were made only for time 

of travel from The Dalles, Oreg., to Vancouver, Wash.; from The Dalles to mouth of 

the Columbia River; and frorr: Salem, Oreg., 

to mouth of the Willamette River. Travel 

times and changes of flow for other tributaries 

were neglected. 

Range of 

flow at lou•er 

end of rea--;h (thousan~.s 

Stream a-nd reach of cfs) 

Columbia River (The Dalles to Vancouver) ____________________ Below 200 

Do ---------------------- ____ 20o-500 Do __________________________ Above 50C 

Columbia River (The Dalles to 

mn!h) --========================::J~oo 25~ Do --------------------------400-600 

Do --------------------------Above 60(' 

Willamette River (Salem to 

mn;h) --========================B2~ 25 

Do -------------------------- 50-75 

Do -------------------------- 75-100 Do __________________________ Above 100 

Travel 

time 

(days) 

1% 

1 

% 

3 

2% 

2 

1% 

3 

2% 

2 

1% 

1 

Travel times were based on data and advice 

from Weather Bureau, Corps of Engineers, 

and Geological Survey personnel, plus some 

observations of velocities at Hc0d River, Vancouver, and a few other points. 

Although the flows at the lower end of the 

reach were the basis for the assignment of 

travel time through the reach, the flows at the 

upper end of the reach were tl'e basis for the 

change in discharge used in adjusting the 

"observed" flows at the ungagen site for travel 

time. For example, in May 1948 the "observed" 

monthly mean flow at Vancouver was 493,500 

cf.s (cubic feet per second). F-:-om the above 

schedule the travel time from The Dalles to 

Vancouver was, therefore, taken as 1 day. 

The daily mean flow at The Dalles was 249,000 

cfs on April 30, 1948, and 999,000 cfs on May 

31, 1948. The change in flow at The Dalles dur-
ing May was, therefore, + 750,000 cfs and the 

needed adjustment to monthly mean flow at 

Vancouver was negative, computed as follows: 

750,000 cfs x 1 day -------= 24,200 cfs. 

31 days 

The "observed" mean flow of 493,500 cfs at 

Vancouver was adjusted to 469,300 cfs. If the 

travel time had been 2 days, then 2 days rather 

than 1 day would have been used in the numerator of the above equation. 

The adjustment of -24,200 cfs shown above 

is about the maximum needed both in amount 

and in percentage of flow and is about 5 percent of the "observed" flow at Vancouver. For 

simplicity, the assumed travel times to Vancouver were used also for the ungaged sites 

below Lewis River and below Cowlitz River , even though it is obvious that somewhat longer 

travel times to those sites should be used., 

A good verification of the applicability and 

validity of the assumed travel time from The 

Dalles to Vancouver was possible because the 

Geological Survey measured flows at Vancouver during the 1964, 1965, and 1966 water 

years. Table 2 shows a comparison of estimated 

"observed" flows and measured flows at Vancouver for those three years. In 28 of the 36 

months of record the adjustment for time of 

travel improved the agreement of the estimated 

"observed" flows with the measured flows. 

The increase in discharge during the spring 

rise in certain years was so large that application of the time-of-travel adjustment resulted in larger flows at Longview than at the 

mouth, but the difference never exceeded about 

2 percent and it is probable that the greater 

upstream flows could actually occur under certain conditions. 

CORRELATION METHOD 

The correlation, or shortcut, method for estimating flows at the ungaged sites was developed for two reasons, ( 1) many of the gaging-station records used in the detailed summation method were not available for many of 

the early years, and (2) for the past 6 or 7 

years the Geological Survey Northwest Data 

Center at Portland, Oreg., has needed a method 

for computing current monthly flows at Vancouv~r, Wash., and at the mouth of the Columbia River, and many of the gaging-station records used in the summation method have not 

been available on a current basis. 

Major Inflow Segments 

In the correlation method the area be~ween 

The Dalles, Oreg., and the mouth of the river 

was broken into three major segmentr and 

separate correlations were used to estimate 

the inflow from each segment. These segments 

are Columbia River from The Dalles to Vancouver, Wash., Willamette River from falem, 

Oreg., to mouth (including Multnomah Channel), and Columbia River from Vancouyer to 

mouth. 

Good estimates of the inflow betweer The 

Dalles ana Vancouver were obtained by· correlating monthly inflow figures for 191:3---65 

(obtained by the summation method) with the 

sum of flows in Hood and Wind Rivers., Separate correlations were made for each 1nonth 

of the year to adjust for seasonal variations 

in the relationship. Figure 2 shows the correlation developed for January. 

5 

Similarly, the flows of Willamette River at 

the mouth correlated well with flows of Willamette River at Salem after both wer~ adjusted for storage changes upstream. Figure 

3 shows the correlation for the month of October. Correlations for each month were used 

to obtain "adjusted" monthly mean flows at 

the mouth of the Willamette for the early 

years, and the adjustments were then subtracted to obtain the "observed" monthly mean 

flows. 

The "adjusted" inflow to Columbia River 

below Vancouver also correlated well with the 

sum of flows in Cowlitz and Lewis Rivers adjusted for upstream storage in Lewis River 

reservoirs. Figure 4 shows the correlation for 

the month of January. Here, too, the adjusted 

inflow obtained through correlation was converted to "observed" inflow. 

Discharges obtained by correlation for these 

three major segments of inflow were then used 

directly to obtain estimated flows at three of 

the five ungaged sites; however, estimated 

flows for the other two ungaged sites required 

further manipulation of data. Estimated flows 

for Columbia River below Lewis River were 

obtained by adding to the flow at Vanc-:mver, 
12~----T---~----r-~---r--r---------~------~----------~------~----~--~ 

11 

10 

January 1943-65 

1~----._ __ _. __ ~--~--~~~--------_. ______ _. __________ ~------~----_.--~ 

4 5 6 7 8 9 10 15 20 • 30 40 50 60 

COMPUTED DISCHARGE, IN THOUSANDS OF CUBIC FEET PER SECOND 

INFLOW INTO COLUMBIA RIVER FROM THE DALLES TO VANCOUVER 

Figure 2.-Correlation for inflow between The Dalles, Oreg., and Vancouver, YTash. 

the flows of Willamette River at mouth, Lewis 

River, East Fork Lewis River, and an increment for Engaged area prorated among the 

months based on East Fork Lewis River. 

Estimated flows for Columbia River below 

Cowlitz River were obtained by a further 

addition of flows for Cowlitz and Kalama 

Rivers and another increment for ungaged 

area distributed according to Kalama River 

monthly flows. 

Precipitation, Evaporation, and Time of Travel 

The procedure outlined above did not result 

6 

in "observed" monthly mean flows comparable 

to those obtained by the summation method 

shown in table 1. Adjustment~ for precipitation on and evaporation from the 400 square 

miles of water surface and for time of travel 

because of changing discharge also had to be 

made. This was done in the SG.me way as for 

the summation method, with tr~ following exception; the evaporation correction applicable 

to flows at the mouth of the Columbia River 

was made an integral part of the correlation 

developed for the inflow segment from Van-
GJ (!) 

<( 

a:: 

0 

len 

:::!!: c 20 <z 

~g 1-U.J 

~en 

=>a:: 

~::e LL. 1- 15 

c::tl 

U..ILL. 

1-

enu 

~iii c=> 

~(.) 

-LL. 

~0 

(!)en 

~ ~ 10 

0< 

.en 

:::!!: :::> 9 UJO 

....I :I: 

;:51- 8 

...... ~ <(u.i 

ffi~ 7 ><( 0::5 

U.Jen 

~0 6 UJ 

:::!!: 

~ ....1 

§ 5 

4 

3 

4 5 

0 

/ 

October 1943-65 

6 7 8 9 10 15 20 30 

COMPUTED DISCHARGE, IN THOUSANDS OF CUBIC FEET PER SECOND 

WILLAMETTE RIVER AT MOUTH (ADJUSTED FOR UPSTREAM STORAGE) 

Figure 3.-Correlation for Willamette River at mouth. 

7 

40 50 
~ 7 . 

/

0 

0 

January 1941-65 

/ 5L-----~----------------~--------~------~----~----~---~--L-~--J 10 20 30 40 50 60 70 80 90 100 

COMPUTED DISCHARGE, IN THOUSANDS OF CUBIC FEET PER SECOND. 

TOTAL INFLOW INTO COLUMBIA RIVER BELOW VANCOUVER, EXCLUDING WILLAMETTE RIVER 

(ADJUSTED FOR EVAPORATION AND FOR STORAGE IN LEWIS RIVER RESERVOIRS' 

Figure 4.-Correlation for inflow below Vancouver, Wash. 

couver, Wash., to the mouth. This procedure 

was used because the same annual evaporation 

of 24 inches and the same monthly distribution 

of that 24 inches were used each year. Precipitation corrections were not made in the 

same manner because the actual amount of 

8 

precipitation by months and years is known. 

ADJUSTED MONTHLY MEAN FLOWS 

The tables of "observed" mont}' ly mean flow 

for water years 1928-65 for each of the five 

ungaged sites were developed uring both the 
summation and correlation methods. Tables of 

"adjusted" monthly mean flows were then compiled by adjusting the "observed" flows for 

upstream storage changes. 

The reservoirs for which adjustments were 

made are: 

1. Nine major reservoirs in the Columbia River 

basin; namely, Kootenay Lake, Hungry 

Horse Reservoir, Flathead Lake, Noxon 

Rapids Reservoir, Pend Oreille Lake, 

Coeur d'Alene Lake, Franklin D. Roosevelt Lake, Chelan Lake, and Brownlee 

Reservoir. 

2. Willamette River basin reservoirs of Hills 

Creek, Lookout Point, Cottage Grove, 

Dorena, Fern Ridge, Cougar, and Detroit. 

3. Lewis River reservoirs of Swift, Yale, and 

Merwin. 

Adjustments for upstream storage were 

computed using the system of adjusting that 

has been standard with the Water Management Subcommittee of the Columbia Basin 

Inter-Agency Committee. In that system, adjustments are made strictly on a calendarmonth basis with no allowance for travel time. 

In other words, in any given month the adjusted flow fr<>r Columbia River at the mouth 

may include an adjustment for a storage 

change that occurred largely during the last 

day or two of a month and the effect would 

not be felt at the mouth until the following 

month. However, such events should not lead 

to consistently large errors. At times during 

the final days of the month one reservoir may 

store while another releases, and the resultant 

differences in flow would tend to cancel each 

other. 

ACCURACY OF ESTIMATES 

Because of the many approximations involved, it is difficult to place accuracy limits 

on the estimates of flow. The ungaged area 

between the mouth of the Columbia River and 

The Dalles, Oreg., is only 1.6 percent of the 

total Columbia River drainage area, and the 

ungaged flow is estimated to be less than 5 

per cent of the total flow.. Therefore, fairly 

large errors in estimates of ungaged flows 

would not greatly affect estimates of total 

flow. However, in some months, the approximations used could easily result in errors of a 

few percent if errors in the several estimates 

9 

were in the same direction. It is morfl likely 

that the errors would be compensating. 

Comparison of Estimated and Measured Flows 

The only real check of the accuracy of estimates lies in a comparison of estimat~~d flow 

for Columbia River at Vancouver, Wash., for 

water years 1964-66 with measured flC''¥S for 

those years (table 2). The estimates for 1964 

and 1965 were by the detailed sum.mation 

method whereas those for 1966 were by the 

correlation method. The mean deviation of the 

three estimated annual mean flows from the 

measured flows is 0.24 percent and maximum 

deviation is only 0.42 percent. Corresp>nding 

figures for the 36 monthly mean flows are 2.3 

and 5.7 percent, respectively. Howeve:r, this 

does not mean that the estimated flows are 

in error by this much, as the measured fLows 

in this tide-affected reach of the riv~~ may 

be a few percent in error. The comparison 

does show that the estimates are rear0nably 

close to the measured flow. It is the author's 

opinion that in general the estimates are accurate to within 2 or 3 percent. 

Comparison of Estimates by Correlation and Summation Methods 

The correlation, or shortcut, method has 

been used to. estimate fLows of the Columbia 

River at mouth for cu,rrent data releaser, Comparison of the 60 monthly estimates thus computed for water years 1961-65 with those 

computed by the summation method and shown 

in table 11 (p. 23) indicates that the z.verage 

difference is 1.7 percent and the maximum 

difference is 4.6 percent. Average difrerence 

for annual mean flows was 0.6 percent. Some 

of this difference is undoubtedly caused by 

the fact that provisional figures of disn.harge 

for index streams were necessarily u';<~d in 

the shortcut method but final published figures 

were used in the summation method to obtain 

the flows for 1961-65 shown in table 11. 

The shortcut method was used to eft;imate 

monthly discharge fr<>r 1928-40 but for those 

years it was possible to use publishe:d discharge for all index stations, thereby eliminating provisional data as a source of error. 

Known Deficiencies in Methods 

:Known deficiencies in the results pre:~ented 

herein are as follows: 
1. The 80,000 acre-feet of water supply for 

Portland, Oreg., diverted from the Sandy 

River basin as of 1955 had gr,own to 

about 110,000 acre-feet per year in 1965. 

Between one-half and two-thirds of this 

amount, or an average of about 100 cfs, 

was returned to the lower Willamette 

River in recent years, but no provision 

for this was made in the computation. 

2. The increment for precipitation on and decrement for evaporation from the 400 

square miles of river surface was inCluded 

in the tables only for Columbia River at 

mouth. Fifty percent of this correction 

was applied below the Cowlitz River. 

Actually, about 40 percent of the water 

surface is above St. Helens, Oreg., but 

these factors were not included in tables 

for the three upstream sites. 

3. Although the compilations used to estimate 

flows for this report take into account 

all known surface runoff, they do not include ground-water inflow directly into 

the rivers below the gaging stations. This 

may be important particularly for the 

Willamette River below Salem, Oreg., 

where inflow is from extensive areas of 

permeable alluvium. The extent of the 

inflow cannot be evaluated until a gaging 

10 

station has been installed at Portland. 

4. Adjustments for changing discharge 

through use of travel timer are only approximate and are used only f,or flows 

passing the gaging stations on Columbia 

River at The Dalles, Oreg., 2nd Willamette 

River at Salem; they are neglected for 

tributary streams. 

5. Adjustments for changes in r·eservoir storage, used to convert "observed" flows to 

"adjusted" flows, are made strictly on a 

calendar-month basis with no allowance 

tor travel time. This could result in occasional small errors. 

REFERENCES 

Hulsing, Harry, and Kallio, Nicholas, 1964, Magnitude and frequency of floods in ti'~ United States, 

Part 14, Pacific slope basins in ,O" .. egon and lower 

Columbia River basin: U.S. Geol. Survey WaterSupply Paper 1689, fig. 3. 

Orem, H. M., 1961, Computation of total flow of the 

Columbia River at the mouth, in, Short papers 

in the geologic and and hydrologic sciences: U.S. 

Geol. Survey Prof. Paper 424-C, p. C148-C149. 

U.S. Weather Bureau, 1950, Mean monthly and annual 

ev•aporation from free water surface for the 

United Jtates, Alaska, Hawaii, and West Indies: 

U.S. Weather Bur. Tech. Paper 13. 

U.S. \Veather Bureau, 1959, Evaporat~on maps for the 

United States: U.S. Weather Bur. Tech. Paper 37. 
TABLES 1-12 

Table !.--Outline of summation method for estimating flow of 

Columbia River at mouth 

Station 

Columbia River at The Dalles Dam 

Klickitat River near Pitt 

Hood River and conduit nr Hood River 

White Salmon River nr Underwood 

Little White Salmon ~above Lapham Creek near Willard 

Wind River near Carson 

Ungaged area-The Dalles Dam to Bonneville Dam 

Columbia River at Bonneville Dam-subtotal 

Washougal River nr Washougal 

Sandy River below Bull Run River nr Bull Run 

Ungaged area-Bonneville Dam to Vancouver 

Columbia River at Vancouver-subtotal 

Willamette River at Salem 

Mill Creek at Salem 

~outh Yamhill River near Whiteson 

Ungaged area-Salem to Wilsonville 

Mollalla River near Canby 

t:; Pudding River at Aurora 

Tualatin River near Willamette 

Clackamas River near Cazadero 

Johnson Creek at Sycamore 

Ungaged area above mouth of Willamette River 

Willamette River at mouth 

Columbia River below Willamette River-subtotal 

Lewis River at Ariel 

*East Fork Lewis River near Heisson 

*Kalama River below Italian Creek, near Kalama 

Cowlitz River at Castle Rock 

*Elochoman River near Cathltrnet 

*Youngs River near Astor~a · 

Precipitation on water surface 

Evaporation from water suiface 

Ungaged area-below Willamett.e River 

Columbia River at mouth-uncorrected 

Sum of change during period-Columbia + Willamette 

Correction for time of trave!'to mouth 

Columbia River at mouth-"observed" 

Adjustment for storage change in reservoirs 

Columbia River at mouth-"adjusted" 

!/Cubic feet per second. 

~/Cubic feet per second per square mile. 

Period Drainage 

of area record sg mi 

18.78- ._ 

1959 237,000 

1928-59 1,290 

1913-59 329 

1935-59 390 

Dec.l944-59 117 

1934-59 225 

945 

240,296 

Sept.l944-59 108 

1929-59 440 

394 

241,238 

1927-59 7,280 

1940-59 110 

1940-59 502 

508 

1928-59 323 

1928-59 479 

1928-59 710 

1908-59 657 

1940-57 28.2 

557 

11,154 

252,392 

1923-59 731 

1929-59 125 

1947-59 201 

1926-59 2,238 

1940-59 66 

1927-58 40.1 

400 

1, 776 

257,969 

257,969 

Mean Anrtuarurscnarge 

cfs!l 

1943-57 

cfsm2/ 

195,300 0.824 

1,752 1.36 

1,216 3.70 

1,219 3.13 

428 3.66 

1,256 5.58 

(1,390) (1.47) 

202,561 0.843 

878 8.13 

2,528 5.75 

(1, 703) (4.32) 

207,670 0.861 

26,560 3.65 

146 1.33 

1,839 3.66 

(1' 103) (2.17) 

1,290 3.99 

1,358 2.84 

1,589 2.24 

2,998 4.56 

57 2.02 

(1, 098) (1.95) 

38,038 3.41 

245,708 0.974 

5,094 6.97 

782 6.26 

1,211 6.02 

9,647 4.31 

385 5.84 

190 4.74 

1,790 4.46 

- 710 1. 78 

(7,246) (4.08) 

271,343 1.052 

0 

271,343 

+1,182 

272,525 1.056 

Remarks 

26 mo.correl.with Underwood. 

Add 1.1 times Wind River. 

24 mo.correl.with Wind River •. 

About 80,000 A.F. diverted to 

Portland in 1955. 

Add 2.2 times Washougal River. 

Partly diverted. 

Add 60% of Whiteson. 

Add 80% of Pudding River. 

1943-46 correl.with Toutle R. 

Avg.precip.for 4 stations. ~vg.figures used for months. 

2.76 x sum of 4 starred rivers. 
Table 2.--Comparison of estimated and measured flows - Columbia River at Vancouverz Wash. 

ater [Tnousanas of CUblC feet per secona] 

Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June . July Aug • Sept. Year ear 

1964 Summation of upstream observed flows 95.74 106.76 106.32 118.22 121.60 119.39 151.63 300.90 588.94 360.38 166.55 109.18 195.40 

Correction for time of travel - .51 + .86 - .17 - .20 - .70 - .19 - 2.20 - 8.48 - 2.23 +12.0 + 2.8 + .3 - .09 

Estimated "observed" discharge 95.23 107.62 106.15 118.00 120.90 119.20 149.43 292.42 586.71 372.38 169.35 109.48 195.31 

Measured discharge 97.5 101.8 105.3 115.7 120.8 119.4 143.3 291.1 585.5 379.3 174.1 114.3 195.6 

Difference - 2.27 + 5.82 + .85 + 2.30 + .1 - .2 + 6.13 + 1.32 + 1.21 - 6.92 - 4.75 - 4~82 - .29 

Percent deviation of estimate - 2.3 + 5.7 + 0.8 + 2.0 + 0.1 - 0.2 + 4.3 + 0.5 + 0.2 - 1.8 - 2.7 - 4.2 - 0.15 

Avg. dev. = 24.8/12 = 2.1% 

1965 Summat1on of upstream observed flows 125.16 118.84 205.15 199.30 254.54 195.78 259.73 413.-52 492.73 296.55 171.12 118.53 237.36 

Correction for time of travel + .24 - .25 - 1.97 - 4.36 + 3.86 + 2.95 - 7.51 - 3.04 + 1.83 + 7.35 + 1.35 + 2.45 + .06 

Estimated "observed" discharge 125.40 118.59 203.18 194.94 258.40 198.73 252.22 410.48 494.56 303.90 172.47 120.98 237.42 

Measured discharge 125.0 113.5 195.4 187.7 255.7 196.7 247.4 409.2 504.4 313.8 182.6 125.1 237.8 

Difference + .4 + 5.09 + 7.78 + 7.24 + 2.70 + 2.03 + 4.82 + 1.28 - 9.84 - 9.90 - 9.13 - 4.12 - .38 

Percent deviation of estimate + 0.3 + 4.5 + 4.0 + 3.9 + 1.1 + 1.0 + 1.9 + 0.3 - 2.0 - 3.2 - 5.0 - 3.3 - 0.16 1-' Avg. dev. = 30.5/12 = 2.5% +=-

1966 Summation of upstream observed flows 1/ 111.7 114.7 121.4 132.5 133.0 150.9 171.2 276.7 349.2 266.6 140.0 102.2 172.6 

Correction for time of travel - + .48 - 1.76 - 2.45 + 1.82 - .80 - 2.19 + 2.16 - 4.88 + 2.10 + 2.44 + 4.57 + .24 - .03 

Estimated "observed" discharge 112.18 112.94 118.95 134.32 132.20 148.71 173.36 271.82 351.30 269.04 144.57 102.44 172.57 

Measured discharge 114.1 113.7 117.6 134.2 129.1 146.9 167.5 266.8 349.1 277.9 152.4 107.3 173.3 

Difference - 1.92 - .76 + 1.35 + .12 + 3.10 + 1.81 + 5.86 + 5.02 + 2.20 - 8.86 - 7.83 - 4.86 - .73 

Percent deviation of estimate - 1. 7 - .7 + 1.1 + 0.1 + 2.4 + 1.2 + 3.5 + 1.9 ... 0.6 - 3.1 - 5.1 - 4.5 - .42 

Avg. dev. = 25.9/12 = 2.2% 

l/Preliminary figures. 
Water 

year 

1928 

1929 

1930 

1931 

1932 

1933 

1934 

1935 

1936 

1937 

1938 

1939 

1940 

1941 

1942 

1943 

1944 

1945 

1946 

1947 

1948 

1949 

1950 

1951 

1952 

1953 

1954 

1955 

1956 

1957 

1958 

1959 

1960 

1961 

1962 

1963 

*1964 

*1965 

Oct. 

165 

91.6 

72.9 

80.9 

76.6 

83.4 

113 

82.6 

81.3 

73.3 

78.3 

96.6 

79.6 

96.4 

128 

85.8 

93.4 

90.2 

79.0 

100 

139 

106 

92.4 

119 

136 

88.6 

105 

116 

116 

118 

103 

104 

189 

102 

97.8 

115 

95.2 

125 

Table 3.--Estimated "observed" flows -Columbia River at Vancouver, Wash. 

[Thousands of cubic feet per second] 

Nov. 

223 

87.0 

65.0 

70.2 

77.1 

113 

158 

119 

69.7 

60.9 

114 

85.7 

90.8 

106 

133 

llO 

97.1 

89.3 

102 

110 

152 

106 

98.7 

157 

125 

87.6 

115 

123 

151 

120 

103 

132 

174 

129 

104 

132 

108 

119 

Dec, 

207 

73.6 

73.8 

65.8 

68.5 

112 

238 

117 

64.3 

63.7 

127 

82.5 

96.4 

91.5 

187 

127 

86.1 

79.0 

107 

177 

126 

109 

117 

168 

135 

88.6 

133 

116 

183 

134 

120 

149 

158 

108 

110 

154 

106 

203 

Jan. 

165 

66.4 

55.0 

64.2 

79.7 

111 

257 

102 

90.9 

47.1 

119 

81.8 

82.3 

93.4 

121 

127 

84.7 

98.1 

136 

119 

143 

88.3 

111 

185 

127 

157 

130 

114 

183 

118 

121 

169 

124 

118 

123 

136 

118 

195 

Feb. 

133 

62.3 

107 

64,4 

68.5 

80.8 

174 

121 

64.0 

60.8 

100 

82.3 

112 

91.7 

131 

137 

86.0 

109 

104 

141 

132 

131 

148 

220 

154 

165 

148 

120 

140 

129 

172 

160 

148 

205 

141 

181 

121 

258 

Mar. 

183 

98.8 

85.5 

92.1 

186 

111 

172 

112 

108 

87.2 

153 

117 

152 

112 

112 

137 

88.3 

103 

154 

149 

124 

172 

191 

182 

157 

150 

148 

128 

185 

177 

166 

175 

144 

191 

124 

142 

119 

199 

Apr. 

224 

115 

151 

152 

253 

160 

301 

153 

207 

139 

244 

193 

222 

153 

204 

357 

107 

130 

246 

203 

185 

237 

235 

268 

268 

162 

175 

159 

356 

206 

228 

222 

284 

190 

230 

183 

149 

252 

May 

503 

224 

255 

250 

452 

325 

430 

295 

444 

254 

401 

350 

279 

244 

273 

367 

176 

300 

464 

456 

469 

506 

345 

474 

473 

263 

379 

214 

548 

523 

395 

358 

312 

338 

315 

267 

292 

410 

June 

518 

392 

302 

279 

488 

638 

389 

450 

430 

365 

524 

316 

324 

253 

399 

499 

295 

435 

508 

466 

854 

430 

606 

472 

421 

521 

517 

454 

658 

497 

470 

519 

397 

602 

407 

401 

587 

495 

July 

323 

230 

237 

204 

321 

440 

224 

321 

221 

257 

325 

240 

213 

148 

290 

409 

179 

257 

310 

279 

335 

202 

507 

355 

275 

330 

534 

420 

320 

211 

211 

372 

295 

242 

247 

260 

372 

304 

Aug. 

182 

142 

155 

132 

172 

220 

154 

198 

143 

149 

149 

149 

133 

125 

169 

197 

128 

134 

165 

159 

187 

134 

203 

189 

149 

163 

224 

192 

168 

132 

126 

176 

162 

128 

163 

144 

169 

172 

*See also measured (published) flows shown in table 2. 

15 

Sept. 

109 

98.4 

105 

The 

year 

244 

140 

138 

103 130 

118 197 

140 212 

108 227 

117 182 

103 169 

102 138 

107 204 

103 158 

111 158 

130 137 

111 188 

106 222 

95.2 126 

98.9 160 

120 209 

107 206 

130 248 

99.5 193 

127 232 

115 242 

100 210 

124 192 

159 223 

119 190 

121 261 

99.7 205 

99.6 193 

157 224 

105 208 

98.3 204 

102 180 

104 185 

110 195 

121 237 
Table 4.--Estimated "adjusted" flows -Columbia River at Vancouverz Wash. 

[Thousands of cubic feet per second] 

Water Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. The 

ear ear 

1928 166 227 196 163 129 195 237 582 475 298 160 99.6 244 

1929 91.0 83.1 69.3 61.5 59.6 103 125 270 392 202 129 90.0 140 

1930 68.2 59.8 74.4 50.5 113 87.7 190 265 304 217 141 98.3 139 

1931 77.7 67.8 61.3 63.9 65.2 96.2 163 286 270 185 121 98.2 130 

1932 73.1 77.8 67.8 75.9 74.4 196 278 490 485 282 157 109 198 

1933 80.6 119 110 108 76.2 113 190 361 666 388 198 132 212 

1934 120 156 257 242 162 184 356 433 355 202 141 100 226 

1935 82.6 126 113 103 117 111 172 342 443 294 177 107 182 

1936 76.4 66.9 61.5 89.4 60.4 110 258 471 403 199 132 96.2 169 

1937 68.5 56.8 63.2 43.9 60.4 88.1 153 298 369 230 136 96.4 139 

1938 78.8 115 123 116 96.0 158 282 441 514 292 136 100 205 

1939 92.7 82.2 79.6 78.6 75.8 122 219 379 303 226 144 97.2 159 

1940 77.0 856. 94.4 76.2 110 160 235 346 308 192 129 107 160 

1941 98.5 101 88.9 87.3 84.2 111 174 275 291 183 122 129 146 

1942 130 128 178 104 118 101 234 332 422 279 164 107 192 

1943 79.6 107 120 114 128 147 409 381 509 389 186 102 222 

1944 88.6 84.6 75.9 61.1 70.0 74.7 128 239 300 170 123 95.1 126 

1945 83.2 83.2 63.6 89.1 102 99.3 138 363 438 237 128 95.1 160 

1946 76.5 103 104 128 94.0 151 277 506 496 289 156 116 209 

1947 99.8 112 175 107 132 143 232 495 455 260 151 107 206 

1948 146 147 120 130 116 113 223 550 819 306 180 129 249 

1949 102 101 94.9 67.0 122 177 273 556 406 187 134 98.5 192 

1950 86.6 101 112 88.3 133 193 248 384 655 466 196 121 232 

1951 123 155 169 167 213 161 293 530 467 338 182 116 243 

1952 142 118 119 91.4 129 127 353 521 448 272 151 93.6 214 

1953 76.2 62.9 65.9 156 149 115 161 366 581 330 166 110 195 

1954 87.6 101 120 103 134 130 204 457 542 551 219 159 226 

1955 110 118 101 85.4 82.6 79.3 151 314 541 408 186 113 191 

1956 115 151 185 167 107 171 364 633 664 314 168 112 263 

1957 110 101 118 74.1 99.8 173 224 643 505 209 127 94.3 206 

1958 91.2 82.8 100 97.7 162 138 244 529 477 209 136 99.1 197 

1959 99.8 136 144 158 123 131 228 413 596 365 175 159 228 

1960 186 165 143 89.1 122 142 291 354 463 293 161 104 209 

1961 93.3 120 86.2 88.5 194 168 191 440 635 231 136 98.8 206 

1962 91.5 86.5 90.2 85.0 112 109 266 368 467 250 165 104 183 

1963 110 127 137 93.6 169 128 187 -338 444 260 148 111 188 

1964 86.5 98.0 82.7 91.5 79.1 93.2 168 361 670 365 173 114 198 

1965 119 109 201 168 202 163 290 454 575 304 178 122 240 

16 
Table 5. --Estimated "observed" flows - Willamette River at mouth 

[Thousands of cubic feet ~er second] 

Water Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Tile 

year year 

1928 22.0 74.4 58.0 69.5 35.7 58.1 72.8 29.6 10.2 6.18 4.87 5.01 35.7 

1929 5.83 13.0 22.7 45.7 35.0 37.5 47.3 35.5 24.4 8.56 5.83 4.6S 23.7 

1930 4.50 4.51 48.7 21.7 85.7 29.0 19.0 22.2 15.1 6,08 4.12 4.12 21.6 

1931 5.40 12.5 17.1 27.6 22.0 40.4 71.3 14.7 10.9 6.29 4.10 3.65 19.6 

1932 6.30 30.7 44.7 71.0 36.9 96.0 56.4 37.1 26.2 10.1 5.83 4,5r 35.5 

1933 6.54 32.7 46.8 75.4 53.6 58.3 42.6 45.4 50.4 16.2 6.88 7.5.1 36.8 

1934 6.92 15.3 83.7 77.7 26.9 28.1 32.5 14.3 8.29 5.35 4.34 4.02 25.7 

1935 11.6 50.7 75.3 66.7 49.7 47.5 43.6 30.6 16.9 8.44 5.01 4.61 34.1 

1936 6.03 12.0 18.9 116 45.0 44.3 39.9 35.2 19.8 8.62 5.25 5.02 29.8 

1937 4.42 4.30 14.5 16.2 63.4 59.7 91.2 45.4 38.1 14.2 6.46 5.65 30.0 

1938 9.29 63.5 70.1 89.7 73.0 86.8 54.4 34.2 15.0 7.04 4.89 4.68 42.5 

1939 5.04 23.0 35.9 37.6 64.0 60.2 30.0 17.9 13.5 7.25 4.43 4.53 25.0 

1940 5.80 5.88 29.9 33.4 79.4 66.8 34.5 17.8 7.09 4.43 3.66 3.92 24.1 

1941 5.76 22.1 42.0 51.2 25.2 16.4 15.0 20.9 13.2 6.76 4.46 8.13 19.2 

1942 9.11 35.3 86.4 42.9 55.2 25.7 17.9 25.0 22.5 10.4 5.37 4.45 28.2 

1943 4.39 63.0 115 103 84.0 29.7 66.4 28.5 27.2 12.8 7.15 6.08 45.5 

1944 14.1 26.4 26.6 30.5 37.0 28.0 34.4 21.3 12.8 6.50 4.27 4.37 20.4 

1945 4.58 11.6 12.9 44.1 76.0 59.0 51.8 49.3 18.2 6.83 4.67 5.73 28.4 

1946 5.75 43.6 77.1 103 57.1 68.6 33.1 26.0 18.6 10.2 5.61 5.49 37.9 

1947 12.5 51.2 98.4 43.0 62.4 42.0 45.3 15.7 17.5 10.2 6.83 5.78 34.2 

1948 44.1 72.1 41.2 93.2 63.1 54.5 48.1 44.1 24.9 10.5 7.01 6.89 42.4 

1949 12.9 33.5 90.7 27.9 104 55.4 38.5 51.3 18.6 8.89 5.82 6.07 37.3 

1950 10.2 17.2 43.9 87.7 94.2 88.6 51.4 38.6 34.7 14.2 7.01 6.19 40.9 

1951 23.0 105 82.8 109 84.7 57.1 35.6 30.4 13.0 7.33 5.60 5.67 46.8 

1952 28.7 37.0 89.7 54.3 83.9 48.4 44.7 31.8 18.0 17.1 6.74 6.23 38.8 

1953 5.62 5.46 22.4 136 102 49.2 33.3 42.7 33.9 12.3 7.54 7.40 37.8 

1954 11.7 47.7 115 88.8 98.8 40.1 44.3 19.2 22.7 12.3 8.34 10.4 43.0 

1955 14.3 24.2 30.4 55.1 34.7 39.7 66.5 36.9 31.8 14.8 8.11 9.07 30.5 

1956 25.0 75.1 155 140 50.3 69.2 49.9 37.4 26.0 11.6 7.73 8.43 54.8 

1957 12.2 33.2 57.5 28.5 43.7 96.8 44.2 25.7 14.8 7.80 6.99 7.71 31.7 

1958 11.7 17.5 77.5 82.0 109 4f.2 46.4 22.7 17.0 9.24 7.02 8.47 36.9 

1959 10.5 56.1 44.8 94.0 69.8 35.8 37.6 31.6 16.4 8.28 6.56 ll.6 35.0 

1960 24.2 22.3 22.8 27.7 71.0 61.9 63.7 50.9 23.7 8.27 7.25 8.03 32.4 

1961 11.0 65.6 53.1 43.3 134 97.0 34.6 34.4 15o4 8.13 7.02 8.13 41.8 

1962 12.8 31.5 78.2 42.3 34.3 52.7 48.2 39.8 18.6 8.47 7.81 7.9:i' 31.9 

1963 23.3 49.8 57.4 19.7 62.7 30.8 70.6 53.6 13.4 10.2 7.44 8.3~ 33.7 

1964 13.4 56.2 35.0 105 48.1 41.7 27.9 26.4 26.7 11.1 8.35 8.7'? 33.8 

1965 10.9 24.3 158 130 74.3 22.5 21.8 18.7 11.1 7.08 6.88 7.43 41.2 

17 
Table 6.--Estimated "adjus:ted" flows - Willamette River at mouth 

[Thousands of cubic feet per second] 

Water Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. The 

year ear 

1928 22.0 74.4 58.0 69.5 35.7 58.1 72.8 29.6 10.2 6.18 4.87 5.01 35.7 

1929 5.83 13.0 22.7 45.7 35.0 37.5 47.3 35.5 24.4 8.56 5.83 4.63 23.7 

1930 4.50 4.51 48.7 21.7 85.7 29.0 19.0 22.2 15.1 6.08 4.12 4.12 21.6 

1931 5.40 12.5 17.1 27.6 22.0 40.4 71.3 14.7 10.9 6.29 4.10 3.65 19.6 

1932 6.30 30.7 44.7 71.0 36.9 96.0 56.4 37.1 26.2 10.1 5.8 3 4.58 35.5 

1933 6.54 32.7 46.8 75.4 53.6 58.3 42.6 45.4 50.4 16.2 6.88 7.54 36.8 

1934 6.92 15.3 83.7 77 0 7 26.9 28.1 32.5 14.3 8,29 5.35 4.34 4.02 25.7 

1935 11.6 50.7 75.3 66.7 49.7 47.5 43.6 30.6 16.9 8.44 5.n 4.61 34.1 

1936 6.03 12.0 18.9 116 45.0 44.3 39.9 35.2 19.8 8.62 5.Z5 5.02 29.8 

1937 4.42 4.30 14.5 16.2 63.4 59.7 91.2 45.4 38,1 14.2 6.46 5.65 30.0 

1938 9.29 63.5 70.1 89.7 73.0 86.8 54.4 34.2 15.0 7.04 4.E9 4.68 42.5 

1939 5.04 23,0 35.9 37.6 64.0 60.2 30.0 17.9 13.5 7.25 4.43 4.53 25.0 

1940 5.80 5.88 29.9 33.4 79.4 66.8 34.5 17.8 7.09 4.43 3.(6 3,92 24.2 

1941 5.76 22.1 42.0 51.2 25.2 16.4 15.0 20.9 13.2 6.76 4.46 8.13 19.2 

1942 9.11 35.3 87.3 42.2 55.6 26.0 18.1 25.2 22.6 10.3 5.r4 3.89 28.2 

1943 4.30 64.1 116 102 83.8 30.3 67.0 28.4 27.2 12.6 7-,07 5,85 45.6 

1944 13.7 25.0 26.6 30.5 37.3 28.6 34.8 21.5 12.8 6.46 4,21 4.10 20.4 

1945 3.99 11.2 12.9 44.1 76.7 59.7 52.2 49.4 18.2 6.75 4.~8 5.23 28.4 

1946 4.55 43.8 77.6 102 57.8 69.3 33.5 26.1 18.5 10.2 5.~o 4. 72 37.8 

1947 11.6 51.3 98.3 43.0 63.1 42.9 45.6 15.8 17.6 10.1 6,76 5.67 34.3 

1948 42.7 71.6 41.2 93.2 63.9 55.1 48.8 44.1 24.9 10.4 6.~2 6.45 42.4 

1949 l1.5 33.5 90.7 27.9 105 55.6 38.8 51.7 18.6 8.79 5.70 5.09 37.2 

1950 9.50 17.3 43,9 88.6 94.3 89.7 52.2 38.8 34.7 14.0 6.fl) 5,14 41.0 

1951 23.2 103 82.6 109 85.1 58.1 36.1 30.9 12.9 7.12 4.f8 4.81 46.7 

1952 27.9 36.9 89.6 54.4 84.8 48.5 45.4 32.1 18.0 17.0 5.~8 5.17 38.8 

1953 4.72 5.38 22.5 139 102 51.6 35.3 44.6 33.9 12.1 6.f6 5.92 38.3 

1954 9.66 48.6 114 90.6 98.9 42.6 48.0 21.2 23.9 11.8 6.72 7.46 43.3 

1955 11.3 21.8 31.8 54.3 37.4 43.1 67.8 42.3 32.2 14.4 6.14 5.85 30.7 

1956 21.1 74.6 160 132 53.6 72.5 54.0 39.7 26.3 11.3 6.35 5.11 54.8 

1957 9.76 28.5 57.5 27.2 52.9 97.8 46.7 27.0 15.0 6.93 5.23 4.14 31.6 

1958 8.05 14.4 82.0 80.1 111 43.4 50.1 24.6 17.4 8.33 5.04 4.96 36.9 

1959 6.43 53.6 44.8 96.9 70.9 40.7 40,.9 32.3 16.4 7.17 4,.11 8.90 35.0 

1960 19.6 19.7 22.6 28.7 74.9 67.2 65.9 51.6 24.2 7.29 5.32 5.21 32.4 

1961 6.65 66.7 48.9 43.9 139 101 38.1 35.7 15.1 6. 71 4 • .17 5.69 41.0 

1962 9.62 31.5 78.4 41.3 37.8 58.3 54.6 40.4 18.8 7.59 5.86 5.19 32.4 

1963 17.8 48.5 53.8 19.8 71.9 34.6 73.6 54.9 13.5 9.42 5.20 5.44 33.7 

1964 7.79 52.6 34.8 107 49.9 47.1 32.9 28.3 28.5 10.4 6.07 4.63 34.0 

1965 5.56 21.2 170 125 70.8 25.3 27.7 21.6 11.8 6.24 4.84 3.53 41.2 

18 
Table I.--Estimated "observed" flows -Columbia River at St. Helens, Oreg. 

[Thousands of cubic feet per second] 

Water Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. The 

year year 

1928 193 314 273 244 174 254 308 542 532 332 188 115 287 

1929 100 105 102 117 99.8 143 170 268 422 240 150 104 169 

1930 78.3 70.4 129 80.7 208 121 176 282 320 244 160 110 164 

1931 87.5 85.5 86.1 99.1 92.5 142 234 267 291 211 136 108 153 

1932 85.9 116 120 160 114 300 321 497 520 334 179 125 240 

1933 92.5 158 170 198 140 180 211 382 700 461 229 150 256 

1934 127 180 358 356 206 209 339 448 399 231 160 114 261 

1935 97.2 185 204 178 179 166 203 332 472 331 205 124 223 

1936 90.4 84.4 87.6 220 115 160 254 487 456 232 151 110 204 

1937 80.6 66.4 83.3 67.2 130 154 244 308 413 274 158 110 174 

1938 90.7 191 212 220 179 249 309 442 543 334 156 114 253 

1939 104 113 125 129 155 185 229 373 333 250 155 109 189 

1940 88.2 99.6 134 122 206 230 263 302 333 218 138 116 187 

1941 105 133 141 152 121 132 171 269 268 156 131 142 160 

1942 141 174 289 169 193 143 226 304 427 302 176 117 222 

1943 92.0 186 254 236 231 175 436 402 532 425 206 114 274 

1944 110 128 118 120 129 121 147 202 311 186 133 101 150 

1945 97.1 105 96.1 152 195 170 189 360 457 265 140 106 194 

1946 86.7 155 196 251 170 232 286 498 533 324 173 127 253 

1947 116 173 295 170 214 198 256 475 487 291 167 114 247 

1948 192 235 175 247 203 186 241 523 885 348 196 139 298 

1949 122 148 210 120 244 237 285 569 453 213 140 107 236 

1950 105 126 171 210 256 294 298 393 649 526 212 134 281 

1951 149 276 266 307 319 246 311 512 489 364 196 122 296 

1952 174 170 236 186 248 213 319 513 433 294 156 108 255 

1953 95.0 94.1 113 317 282 207 202 311 561 346 172 134 236 

1954 121 170 264 230 258 197 228 405 547 551 234 171 273 

1955 135 154 155 177 163 172 234 257 495 439 202 131 226 

1956 150 243 355 337 198 264 415 595 692 336 178 132 325 

1957 135 161 202 153 179 286 260 555 515 220 140 108 243 

1958 118 127 208 215 295 215 284 424 491 221 134 109 236 

1959 117 198 200 276 238 218 267 397 541 383 184 173 266 

1960 222 206 190 159 229 214 357 372 426 305 170 118 247 

1961 116 204 170 171 360 301 232 381 622 252 137 109 253 

1962 114 143 200 176 183 185 284 361 429 257 172 112 218 

1963 142 196 222 165 250 179 263 327 416 272 153 114 224 

1964 112 176 151 237 180 171 183 323 618 387 180 120 236 

1965 140 152 379 340 342 227 279 434 509 312 181 130 285 

l9 
Table 8.--Estimated "adjusted" flows - Columbia River at St. Helensz Oreg. 

[Thousands of cubic feet per second] 

Water Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. The 

year ye~r 

1928 193 317 262 242 170 265 321 622 489 306 166 106 287 

1929 99.8 101 98.1 112 97.1 147 180 314 422 212 136 95.6 168 

1930 73.6 65.2 130 76.2 214 123 214 292 322 225 146 103 164 

1931 84.3 83.0 81.6 98.8 93.3 147 245 305 283 193 126 103 153 

1932 82.7 117 120 156 120 309 347 535 517 295 164 115 240 

1933 89.2 166 168 195 135 181 241 417 729 409 207 143 257 

1934 134 179 376 340 194 221 394 451 365 208 147 105 260 

1935 99.6 192 200 179 174 166 222 379 464 305 184 113 223 

1936 83.8 81.6 85.3 221 111 162 304 514 428 210 139 102 204 

1937 74.0 62.1 85.8 62.4 129 157 258 352 417 247 143 103 174 

1938 90.0 194 209 217 175 254 347 482 533 301 142 106 254 

1939 99.4 111 124 126 148 190 256 402 320 235 149 103 189 

1940 84.3 93.4 136 115 204 238 276 370 317 198 134 112 190 

1941 106 129 138 146 114 131 192 300 306 191 128 141 169 

1942 144 169 280 151 181 132 257 362 450 291 171 112 225 

1943 85.2 185 248 223 222 177 488 416 542 404 195 no 274 

1944 105 113 108 96.9 113 108 169 265 316 178 129 100 150 

1945 88.5 98.5 80.8 144 190 167 198 423 459 245 133 102 194 

1946 82.5 157 193 242 160 229 318 540 521 303 163 122 253 

1947 us 175 293 159 205 193 285 515 476 272 159 ll4 247 

1948 198 230 169 234 188 175 280 604 849 319 189 137 298 

1949 ll7 143 196 97.5 237 242 320 619 430 198 141 105 236 

1950 98.8 128 165 187 241 298 311 433 699 484 205 128 281 

1951 153 273 267 289 312 225 337 568 484 347 188 122 297 

1952 179 162 220 150 225 181 407 561 460 291 158 99.8 259 

1953 81.8 69.2 93.0 320 263 174 203 419 621 346 174 ll7 240 

1954 99.7 159 250 205 246 180 262 486 573 567 227 168 277 

1955 124 148 141 147 128 127 227 364 582 428 194 121 228 

1956 146 243 362 312 166 255 428 683 698 329 176 118 327 

1957 124 136 188 105 161 283 281 677 524 218 133 99.4 244 

1958 101 102 195 190 287 187 305 560 497 219 142 105 240 

1959 108 205 200 270 201 186 278 453 619 374 181 172 270 

1960 214 194 173 123 208 218 368 415 493 302 168 111 248 

1961 103 199 142 144 354 28l- 237 484 654 239 142 106 256 

1962 104 124 182 135 157 174 330 416 490 260 172 no 221 

1963 132 190 200 ll9 250 168 271 400 460 271 154 ll7 227 

1964 96.6 163 125 214 136 148 208 396 706 379 182 121 239 

1965 127 138 387 307 283 193 326 482 590 311 184 127 288 

20 
Table 9.--Estimated "observed" flows -Columbia River at Longviewz Wash. 

[Thousands of cubic feet per second] 

Water Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. The 

;rear 

1928 205 341 289 266 182 273 326 558 539 336 190 117 ~ 300 

1929 105 112 112 125 106 155 184 284 436 245 152 106 177 

1930 80.3 72.3 140 88.0 234 132 188 293 327 247 161 112 172 

1931 90.3 90.5 91.9 114 104 158 254 276 297 214 138 110 161 

1932 91.7 129 136 178 129 328 341 513 534 341 182 126 253 

1933 96.9 188 194 223 ISO 197 224 398 722 471 234 156 271 

1934 140 194 426 394 219 227 351 456 404 233 162 116 277 

1935 108 213 228 201 195 179 213 344 482 337 208 127 236 

1936 93.4 88.8 95.4 246 128 176 268 506 471 237 153 112 215 

1937 82.6 68.2 96.5 73.5 142 169 267 325 432 280 160 113 184 

1938 94.4 217 239 242 191 265 326 457 552 337 158 116 266 

1939 108 123 141 148 174 199 241 385 342 254 157 Ill 199 

1940 91.2 104 153 132 231 249 276 314 337 220 139 118 197 

1941 109 141 154 164 129 138 177 277 273 158 133 147 167 

1942 149 186 315 178 205 151 235 313 438 308 178 119 231 

1943 94.7 210 277 250 250 188 457 413 543 431 209 116 286 

1944 115 134 130 131 140 130 157 211 318 189 135 104 158 

1945 99.8 112 104 168 214 184 202 379 465 269 142 110 204 

1946 89.9 172 217 275 188 249 300 515 548 333 176 129 267 

1947 124 192 330 187 234 210 270 485 495 295 169 117 259 

1948 209 258 192 267 221 198 254 544 901 354 199 142 312 

1949 128 164 232 126 265 254 •300 591 465 219 144 110 249 

1950 110 142 191 230 283 321 316 409 668 536 216 137 296 

1951 160 301 295 331 347 260 325 526 497 368 198 125 311 

1952 188 185 256 196 266 224 334 527 442 299 159 109 266 

1953 96.7 96.2 121 356 306 218 212 326 573 353 176 137 247 

1954 126 183 297 253 285 210 244 419 563 562 239 175 288 

1955 141 168 169 191 179 183 250 271 514 450 206 134 238 

1956 165 274 391 363 210 285 434 615 708 345 182 135 342 

1957 144 172 224 161 194 308 275 569 523 224 142 110 254 

1958 121 134 228 235 318 225 300 437 500 224 136 111 247 

1959 121 224 223 306 252 231 282 411 554 388 187 180 280 

1960 236 226 208 169 249 228 375 390 438 310 173 120 260 

1961 121 232 183 191 397 325 248 397 634 256 139 112 268 

1962 119 152 222 192 195 196 300 373 439 262 176 114 228 

1963 150 219 240 175 270 190 280 339 423 276 156 116 236 

1964 117 193 164 266 193 185 195 336 636 396 185 124 249 

~965 145 165 414 367 364 237 291 445 518 316 183 132 298 

21 
Table 10.--Estimated "adjusted" flows -Columbia River at Longview, Wash. 

[Thousands of cubic feet per second] 

Water Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. The 

year ear 1928 206 345 277 264 177 285 340 637 496 311 169 108 300 

1929 104 108 108 120 103 160 194 330 4,36 217 138 97.2 177 

1930 75.6 67.1 141 83.5 239 134 226 302 328 228 148 105 172 

1931 87.1 88.0 87.4 114 105 163 265 315 290 196 127 105 162 

1932 88.5 130 135 174 135 338 366 551 530 302 167 116 253 

1933 93.6 195 191 219 146 199 253 433 751 420 212 148 272 

1934 147 193 445 379 208 239 406 459 369 211 148 107 276 

1935 llO. 220 224 202 190 179 233 391 475 310 187 116 236 

1936 86.8 86.0 93.1 247 124 179 318 533 444 215 141 104 215 

1937 76.0 63.9 99.0 68.8 142 172 281 369 436 253 146 106 184 

1938 93.8 220 236 240 187 270 364 497 542 304 144 108 267 

1939 ll3 120 140 144 167 205 268 414 329 240 152 105 199 

1940 87.3 97.4 154 126 229 257 290 382 321 200 135 114 199 

1941 110 137 151 158 121 137 198 309 311 193 130 146 175 

1942 152 181 306 160 193 140 265 372 461 296 173 113 234 

1943 87.9 209 271 237 241 190 509 428 553 410 198 112 287 

1944 llO 119 120 108 124 117 135 274 323 181 130 103 157 

1945 91.2 106 89.0 161 208 181 211 442 468 249 135 106 204 

1946 85.7 174 214 266 179 246 331 557 536 312 166 124 267 

1947 122 194 328 175 225 205 299 524 483 276 161 117 260 

1948 215 253 186 ~54 206 188 293 625 866 324 192 140 312 

1949 123 159 218 104 259 259 335 641 442 204 144 108 249 

1950 104 144 185 208 268 324 330 449 717 494 209 130 296 

1951 164 298 296 313 340 239 352 582 492 351 191 125 312 

1952 193 177 240 160 243 192 422 576 469 296 161 102 270 

1953 83.4 71.3 101 359 287 185 214 434 633 353 178 120 251 

1954 105 172 283 227 273 193 277 500 589 577 232 172 292 

1955 129 161 155 160 144 137 244 378 601 438 198 124 239 

1956 161 274 397 338 177 276 447 703 714 338 181 122 345 

1957 133 146 211 113 176 305 295 691 532 221 136 101 255 

1958 104 110 216 211 310 197 322 573 506 222 144 107 251 

1959 113 231 223 300 214 199 293 467 632 380 184 178 284 

1960 228 215 191 133 229 232 386 434 505 306 171 114 261 

1961 108 226 156 164 391 306 253 501 666 244 144 108 271 

1962 109 133 203 152 168 185 346 428 500 264 176 113 232 

1963 139 214 218 129 270 179 288 412 466 275 157 120 238 

1964 101 180 149 243 ISO 161 221 410 725 388 186 125 252 

1965 132 151 422 334 305 203 337 492 598 315 187 129 300 

22 
Table 11. --Estimated "observed" flows - Columbia River at mouth 

(Thousands of cubic feet per second] 

water Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. The 

year z:e;:tr 

1928 213 352 304 282 189 282 333 545 558 343 195 119 307 

1929 108 119 120 132 108 163 187 280 437 256 153 107 181 

1930 82.5 73.8 148 93.0 246 138 188 294 328 252 165 114 176 

1931 92.9 94.3 97.0 123 112 166 264 273 300 218 141 112 166 

1932 95.3 138 144 188 134 345 345 512 534 354 185 129 259 

1933 100 203 205 239 155 205 221 396 720 481 242 161 278 

1934 147 203 452 424 232 236 346 459 410 240 165 118 286 

1935 115 226 241 215 206 187 212 337 486 342 215 129 243 

1936 96.3 92.9 101 263 132 187 260 508 478 245 156 115 220 

1937 83.8 69.5 104 77.3 147 177 274 320 434 288 164 115 187 

1938 97.1 230 254 257 198 272 325 453 561 350 163 117 273 

1939 110 129 149 159 182 202 245 382 348 259 161 113 203 

1940 92.2 108 164 140 240 261 279 312 342 226 143 119 202 

1941 111 150 160 174 132 140 178 276 278 161 133 152 171 

1942 154 193 331 185 217 155 231 311 444 313 183 121 237 

1943 96.8 220 290 264 263 191 460 412 545 438 217 119 293 

1944 118 138 137 137 147 135 161 208 318 195 136 105 161 

1945 101 119 109 180 224 193 207 373 468 278 145 113 209 

1946 91.4 180 222 302 199 257 297 510 559 344 180 131 273 

1947 128 201 351 197 244 214 270 479 501 303 174 119 265 

1948 215 272 201 280 227 209 258 527 917 371 202 146 319 

1949 132 175 249 130 278 264 295 587 478 224 146 111 255 

1950 113 149 205 243 295 340 322 405 664 548 224 140 303 

1951 164 319 309 350 360 268 325 519 503 375 205 127 318 

1952 196 194 268 204 279 227 333 525 461 306 162 111 272 

1953 97.2 97.3 130 380 320 224 212 325 577 360 181 139 253 

1954 128 191 316 264 304 217 250 411 569 468 248 179 295 

1955 144 176 178 201 187 189 260 271 508 459 213 137 244 

1956 174 289 410 384 217 296 432 612 720 356 188 137 351 

1957 150 179 237 165 195 324 279 558 535 232 146 111 259 

1958 123 140 239 246 331 234 306 427 511 234 138 112 252 

1959 124 238 234 320 263 238 285 412 551 402 193 180 286 

1960 244 236. 220 174 263 229 388 393 440 314 181 120 266 

1961 125 241 192 202 416 342 255 384 640 268 141 113 276 

1962 121 159 236 198 203 201 300 373 444 269 180 117 234 

1963 153 230 251 182 278 194 290 335 428 285 158 117 241 

1964 119 205 172 284 201 194 199 328 635 408 188 125 255 

1965 147 173 433 378 380 244 284 445 520 327 185 135 304 

23 
Table 12.--Estimated "adjusted" flows -Columbia River at mouth 

[Thousands of cubic feet per second] 

Water Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. The 

year year 

1928 214 356 293 280 185 293 346 624 516 318 174 110 307 

1929 108 115 115 128 105 167 197 326 437 228 140 98.5 180 

1930 77.8 68.5 148 88.5 252 140 227 303 329 233 151 107 176 

1931 89.8 91.8 92.5 123 113 170 274 311 293 201 130 107 167 

1932 92.1 138 144 184 140 354 370 550 531 315 170 119 259 

1933 96.7 211 203 235 150 207 250 432 748 429 220 153 278 

1934 154 201 471 409 220 248 400 462 375 218 151 109 286 

1935 117 234 237 216 201 186 232 384 478 316 194 118 243 

1936 89.7 90.1 99.1 264 128 189 311 536 450 223 144 107 220 

1937 77.2 65.2 106 72.6 147 180 288 364 438 261 150 108 188 

1938 96.5 233 251 254 194 277 362 492 551 317 150 109 274 

1939 105 126 148 156 175 208 271 410 336 244 155 106 204 

1940 88.4 102 165 134 238 268 292 380 326 206 139 115 204 

1941 113 146 158 168 125 139 198 308 316 196 130 151 179 

1942 156 188 323 167 205 144 261 369 468 302 178 115 240 

1943 90.0 220 284 250 254 192 512 427 555 417 206 114 293 

1944 112 124 128 114 131 122 183 270 323 187 132 104 161 

1945 92.7 112 93.8 172 218 190 217 436 470 258 138 108 209 

1946 87.3 181 219 293 190 254 329 552 546 323 170 126 273 

1947 126 203 349 186 236 210 300 519 490 284 166 119 266 

1948 221 266 195 266 212 198 297 608 881 341 196 144 319 

1949 127 170 235 108 271 268 331 638 454 209 147 109 255 

1950 107 152 199 220 281 343 336 445 713 507 216 134 304 

1951 168 316 310 332 353 247 351 575 498 358 197 128 319 

1952 201 186 252 168 255 196 421 573 488 303 164 103 276 

1953 84.0 72.5 110 383 302 191 214 433 637 360 182 123 257 

1954 107 180 302 239 292 200 283 492 595 484 241 176 299 

1955 133 169 164 170 152 144 254 378 595 448 206 127 245 

1956 170 289 416 360 184 288 445 700 726 349 186 124 353 

1957 139 153 224 117 176 322 300 680 544 229 139 102 260 

1958 106 115 227 222 323 206 327 563 517 232 146 108 257 

1959 115 245 234 314 225 206 296 468 629 394 190 178 290 

1960 236 225 203 138 242 233 399 436 507 310 178 114 268 

1961 112 236 164 175 410 323 260 488 673 255 146 110 279 

1962 111 140 218 158 176 190 347 428 505 271 180 116 237 

1963 143 224 229 136 278 184 298 409 471 284 160 121 244 

1964 104 192 147 261 158 171 224 401 724 400 190 126 258 

1965 134 159 441 345 321 210 330 492 601 326 189 131 306 

24 

* U. S. GOVERNMENT PRINTING OE'FICE : 1968 0 - 286-986