WORKING PAPER NO. 51
STANDARD
FOR
HYDROLOG1C ANALYSIS PROCEDURES
DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service, Pacific Northwest
Region IX
Portland, Oregon
December 1964
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Hydrology Committee
12/7/64
HYDROLOGIC COMPUTATIONS FOR RIVER BASIN STUDIES
INTRODUCTION
The purpose of this paper is to describe a procedure for the hydrologic
computations necessary to river basin studies. For this paper "hydrology" is
defined as the science dealing with water, its properties, phenomena and distri-
bution, especially with reference to water on the surface of the land, in the
soil and underlying rock, and in the atmosphere. This definition implies that
quantity and quality are hydrologic factors that are inseparable for a complete
analysis of existing data. However, it is proposed herein to separate the
computations by obtaining and analyzing data on quantities of flow, and later
*
superimposing quality data upon the quantity analysis to determine flow and
storage needs for water quality control.
Because the river basins in the Pacific Northwest have climatic conditions
ranging from coastal, through maritime and mountain to arid semi-desert in the
space of a few hundred miles, it is necessary to describe for each basin a base
system from which decisions may be made regarding pertinent data to be used in
the analysis. It is the responsibility of the basin engineer for each basin to
set up the base system and determine where data are needed and how much informa-
tion is necessary for his particular basin or project.
RECOMMENDED PROCEDURE
A set of instructions giving procedures for determining flow regulation re-
quirements for quality control" was used as a basis for this paper and is con-
/
sidered an integral portion of this paper.
T7F. H. Rainwater, "Hydrologic Aspects of Analysis of Flow Regulation
Requirements for Quality Control", DHEW, PHS, February 1964.
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12/7/64
It is recommended that the basin or project engineer for each area start
the hydrologic analysis by defining the base system in the following steps:
1. Obtain a map(s) of the basin showing topography, streams, cities,
roads and other data necessary for location of points on the base system.
2. Draw or obtain a "stick" diagram^' (example Figure 1) showing the
schematic layout of the basin with streams, cities, industries, gaging stations,
dams and reservoirs, irrigation diversions and returns, quality data stations
and any other data that appear to affect the quality of the waters in the basin.
3. Gather all available data from the files, consolidate information and
put pertinent portions on "stick" diagram.
a. Economics
b. Water uses (irrigation, fisheries, recreation, power,
navigation, etc.)
c. Municipal and industrial water supplies'
d. Municipal and industries wastes
e. Geology, meteorology, physiography
f. Water quality .
g. Surface water hydrology
h. Ground water hydrology
i. Existing and proposed dam and reservoir data
4. Make a reconnaissance tour of the area to become familiar with areal
problems.
_!/ Some of these have been prepared by Mr. Fischman.
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12/7/64
5. Outline the proposed plan for the basin and assemble a committee com-
posed of the technical administrative group for the purpose of:
• J
a. Dividing tfye area into reaches that can be analyzed efficiently
and effectively.
b. Deciding on objectives and criteria that will be most useful for
evaluating the flows needed for quality control in each reach.
After the base system has been established, low flow frequency graphs at
selected points within each reach are needed. In the Pacific Northwest these
are not available through other agencies and this office has to supply them.
These are in general based on USGS surface water records. It is recommended
that a base hydrologic period of time from 1931 through 1960 be used. At
present there is no standard base period among the agencies in the Northwest;
however, the selected time includes 1931 which is considered by the Corps of
Engineers and the Bureau of Reclamation as the critical low flow year.
There are, of course, many exceptions such as the case in which only a
few years data are available, or dams, reservoirs and irrigation diversions
have changed the regimen of the stream during the period of record. Such cases
are unique and the project engineer must decide the validity of data and result-
ing graphs. Correlations with other stations or different statistical procedures
I/ 2/ 3Z4/
may be required for making the decisions. Several papers—'*— »—*— are avail-
able as background information.
ll USGS Water Supply Paper No. 1543A
2/ USGS Water Supply Paper No. 1541A and C
3/ Linsley, Kohler, Paulhus, Hydrology for Engineers . .
4/ Beard, Leo R., "Statistical Methods in Hydrology", Corps of Engineers,
Sacramento, Calif., January 1962.
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1
, . TWIN SPRINGS DAM
I \ (Proposed C. of E.)
LUCKY PEAK
RESERVOIR
HILL CREST PUMPING
PLANT (PROP. U.S.B.R.)
South Fk.
ARROWROCK
RESERVOIR
BOISEDIV.DAM
NEW YORK CANAL to
LAKE LOWELL and
.other DIVERSIONS
ANDERSON RANCH
•DAM and RESERVOIR
LONG TOMDIV. DAM
and TUNNEL fProp.U.S.B.ffJ
0
m>
m
o rn
— o
H>
m
GUFFEYDAM
ondRESERVOIR ^\
(Proposed U.S.B.R.) '
O
Dam a Reservoir
Diversion Dam
O Cities
CO
D*
(D
n>
rt
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12/7/64
The office procedure recommended for computing low flow frequency data
is set forth in the following description and data sheets:
1. A description of each critical point is made by filling in the blanks
of Sheet 1.
2. Flow data are tabulated for the chosen period of record on Sheet 2.
Data sources are shown. Appropriate means are calculated for the water year,
climatic year or calendar year. The June 11, 1964 memorandum from Frank H.
Rainwater in Appendix I explains the differences involved in the use of each
period of time.
3. The flow data are ranked in ascending order of magnitude (Sheet 3).
Median monthly values for the period of record are added and divided by 12 to
give a median-annual mean. Ratios of each monthly median to the median-annual
mean are computed to give an expected monthly distribution of flows.
4. The ranked values of annual means for the water year, climatic year,
or calendar year, whichever fit the particular climatic area involved in the
basin, are plotted on the frequency diagram of Sheet 4 using plotting positions
N+l
as determined by the recurrence interval T= M . These recurrence intervals
have been computed for periods of record from 10 through 42 years in Sheet 7
for convenience in plotting.
5. Tabulate at the bottom of Sheet 5 the annual means from the frequency
diagram at probabilities of exceedance of 0.9, 0.7, 0.5, 0.3, and 0.1, which
correspond to recurrence intervals 1.1, 1.4, 2.0, 3.3 and 10 years respectively.
Tabulate the ratios found in 3 above in the column headed % of annual mean.
Multiply the annual mean at each recurrence interval by the monthly ratio to
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12/7/64
obtain the expected flow for the month. These values can then be plotted on
v
Sheet 6 to give monthly hydrographs for the various recurrence intervals.
Quality data are associated with the quantity data by the equation:
Qb cb= Qa-b ca-b
where: Qb = flow in cfs or mgd at point B
Cfa = concentration in mg/1 at point B
Q b ^a-b = ^e al§ebraic summation of the
products of flow and concentra-
tion between points A and B
if
Mr. Rainwater's procedureAs based on this equation. All withdrawals
and additions of water are tabulated. Appropriate quality values are associated
with the quantities by the detailed method shown. The end result is a presenta-
tion of streamflow regulation needs for quality control.
Use of this method depends on the quality data available in each basin.
In general, it is preferable for each quality variant used to plot the changes
in the variant with changes in flow in the stream. From such a graph it is
possible to pick expected quality data that corresponds to the expected quanti-
ties computed above. It is probable in the Pacific Northwest that there are
areas in which data are not available. In such cases it may be necessary to
make spot measurements and attempt a correlation with adjacent or like areas.
Problems of this type will have to be solved individually as they appear, but
the majority of basins are expected to have adequate data for implementing
these recommendations.
\l F. H. Rainwater, "Hydrologic Aspects of Analysis of Flow Regulation
Requirements for Quality Control", DREW, PHS9 February 1964.
HYDROLOGY COMMITTEE
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Sheet 1
BASIN
HYDROLOGIC QUANTITY ANALYSIS
STATE
COUNTY
River or stream
tributary to
Gaging station designation: Name_
Data determined at station:
Flow
Quality
Temperature
No0
Location
Elevation
Drainage Area
Length of record
Discharge Data:
Average discharge
Maximum day
Minimum day
cfs_
cfs
cfs
Regulation above station
Diversions above station
Source Document(s):
Acre-feet
Date
Date
Supplemental Data:
Nearest meteorological station(s)_
Mean annual rainfall
Mean annual temperature
Sourc e Document(s):
Remarks:
Length of record_
Length o£ record
Date
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Sheet 2
HYDROLOGIC QUANTITY ANALYSIS
Station Name and No.
(All units in cfs)
Entries by
Analysis by
.Date
Date
1
2
3
4
b
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
WSP No.
Water Year
MEAN
OCTOBER
NOVEMBER
DECEMBER
JANUARY
FEBRUARY
MARCH
APRIL
MAY
JUNE
JULY
AUGUST
SEPTEMBER
MEANS
Water Yr.
Climatic Yr.
Calendar Yr.
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Sheet 3
HYDROLOGIC QUANTITY ANALYSIS Entries by
Sfaf-irm ^am^ and N" - (All iinit-s in cfs except 7.) Analysis h
/
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
29
30
31
32
33
34
35
36
37
38
39
40
41
42
NOTES
MEDIAN
Distribution Ratio
(2, medians /12)
OCTOBER
NOVEMBER
DECEMBER
JANUARY
FEBRUARY
MARCH
APRIL
MAY
JUNE
JULY
AUGUST
SEPTEMBER
' Date
y Date
MEAN OF YEAR
Water
Climatic
1
Calendar
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FREQUENCY DIAGRAM
Sheet
o
UJ
LU
o
x
o
>-
CD
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Sheet 5
EXPECTED FLOWS IN CFS AT STATION
FOR VARIOUS RECURRENCE INTERVALS
Month
January
February
March
April
May
June
July
August
September
October
November
December
7o Of
Annual
Mean
Annual \ Vfagfp.
Recurrence Interval
lol
Io4
2.0
3.3
10
Computed by_
Date
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EXPECTED FLOWS in c.f.s. at Station.
Sheet 6
.for various Recurrence Intervals
CO
u:
o
CO
=£
O
_J
U.
Q
LU
I—
O
UJ
a.
x
UJ
_LL
2.O
J.
3.3
10
RECURRENCE INTERVAL
by.
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PAGE NOT
AVAILABLE
DIGITALLY
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«M NO. It
MAT IHI COITION
••* OCM. I«IO. NO. 0
HEALTH SERVICE-BSS
DATE: •
JUN i
* ' • • '••,,» :'•.'*• l
•' :i"''-;''V";W.'•','';,.'.••!
''.'.'...'•'.'.,'••';••'-' ''""•'•'•'''••'
„• <•• ' .UNITED STATES GOVERNMENT
^'Memorandum
TO . : -Project Director .
• Columbia River Basin Project
FROM : Western Operations Officer (WPS)
••'••". Technical Services Branch
». . DWS&PC "'•• •
SUBJECT:. Hydrologic Procedures and.Methods
v Mr. Haywood and I have discussed the content of your June 9,
..--. memorandum on this subject; and he has asked me,to reply. •
>;It has not been our intent to dictate the use .of the climatic year-
data in flow regulation studies. The technical essence of its recom-
•'.v.mendation is presented in paragraph 2 of your memorandum.
• ••Enclosed are copies of illustrations showing normal periods of low ;'',:'.,-
•;. flow and normal distribution of runoff by months. These are from . -.;;;,."
'*'.. USGS Water Resources Review Supplement No. 2 by Earl Harbeck and '.V-£ •
'.Walter Langbein. In reference to figure 10, the runoff 'characteristics. '.•'/' .'•':•
'.'•'. within your Project area demonstrate the inadvisability of establishing •'£•;;
. ' a uniform nation-wide procedure. On the basis of these data describing >-•;
••". -natural runoff patterns, I would be a little sceptical of using the ^ \.^\
; .water year in .Southern Washington and in Oregon because minimum flows ' ' yiy'
'•• normally occur in August or September and the droughts may often .--.^
'•'. extend into October, as you pointed out. There certainly would be •<;£,'
.;:•'-.. no objection to using the calendar year in this area however. Conversely;^;"
•; .the calendar year would not be appropriate in the Snake River Basin y^
;;: 'because the low flow periods commonly occur during the winter months. .- „
: .It is understood, of course, that irrigation practices may. completely '.Jr
'• . change these normal runoff patterns. ' ... ." "•
; There is some merit in maintaining compatibility with work done by other
", State and Federal.agencies with whom you coordinate your activities.
. -. However, we don't-want to coordinate to the detriment of our,own .,
;: program.. The needs .of the agencies naturally differ. For example, • ;
;• the Corps is interested in controlling flood volumes and consequently
:/.. would probably use the water year. The Bureau of Reclamation is concerned'
•' ; with irrigation; hence, the calendar years serves their purpose best. .,•/,;'
,' We are interested ia low flow regulation, consequently, should pidc^-^j:.^;^1.'
''•:'• periods.to "best serve pur needs. . V.; .' -. '. \- ']'"*:-'''(&
'•01
Frank H,''Rainwater
Enclosure
;•': ^]si •:; : Buy U.S. Savings Bonds Regularly oh the Payroll Savings Plan '. ^:' ^ > L/ J'*-.••..-:•>' ^ :$
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A.-Winter.
B.-Early spring.
C.-Late spring.
D.-Mid-summer.
E.-Fall.
Figure 9.—Seasons of highest flows
A.-Late summer
and fall. .
— B.-Winter and
early spring
C.-Early summer
D.-Late fall.
Pigura 10.—Seasons of lowest flows.;.'
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. ^ A „ •!_„ _• u • * T An« •._« «f BAH/* JtlA • " • *^ .__...» __....m. « _"* _ . _ «&
— "~V" >v
tXPLAMATION
Ondinott tfion potent of annual runoff (hot
oceurt In tach moith of ttii year.
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