Surf ace-Water Hydrology of 

California Coastal Basins 

Between San Francisco Bay 

and Eel River

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1851

Prepared in cooperation with the 

California Department of 

Water Resources
Surf ace-Water Hydrology of 

California Coastal Basins 

Between San Francisco Bay 

and Eel River

By S. E. RANTZ and T. H. THOMPSON

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1851

Prepared in cooperation with the 

California Department of 

IVater Resources

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1967
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

Library of Congress catalog-card No. GS 67-264

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

Washington, D.G. 20402
CONTENTS

Page

Abstract ._____________________________________ 1

Introduction...___________________________________________________ 2

Purpose and scope_____________________________________________ 2

Other investigations__________________________________________ 4

Acknowledgments. ____________________________________ 5

Description of region_____________________________________________ 5

Geology and physiography____________________________________ 5

Climate._____________________________________________________ 6

Description of the individual basins__________________________ 7

Napa River basin_________________________________________ 7

Sonoma Creek basin_______________________________________ 8

Petaluma River basin______________________________________ 8

Marin County basins____-_______________________-________- 8

Russian River basin_______________________________________ 10

Small basins in Sonoma, Mendocino, and Humboldt Counties _ 11

Precipitation______________________________________________ 11

Runoff______________________________________ 14

Mean annual volume_________________________________________ 14

Average annual water loss and evaporation from water surfaces_____ 15

Flow duration and regimen of flow_-____-_______----_-------_~_- 16

Low flow magnitude, duration, and frequency______________________ 24

Flood frequency_________________________________________ 28

Method of analysis____________________________________________ 28

Application of regional flood-frequency relations.__________________ 30

Maximum recorded peak discharges____________________________ 31

High flow magnitude, duration, and frequency.______________________ 32

Selected references_________________________________________________ 34

ILLUSTRATIONS

PLATE 1. Hydrologic maps of California coastal basins between San

Francisco Bay and Eel River___________________ In pocket

FIGURE 1. Index map showing location of report area_______________ 3

2. Graphs showing trends in precipitation and runoff________ 13

3. Flow-duration curves of daily discharge for selected gaging

stations for period 1931-63____________________ 18

4-7. Graphs showing relation of:

4. Pmean tO Qmean------------------------- ------ 20

5. QiotoQUe_n 21

6. QSQ to Qmean .__-___.____-.___,_----- -- 22

7. Q90 toQm- an ___-________________--_--___-__-_ 23

m
IV CONTENTS

FIGURE 8. Low-flow frequency curves for Navarro River near Navarro_

9. Frequency-mass curve and storage-draft lines for Navarro 

River near Navarro for 20-year recurrence interval_____

10. Flood-frequency curve for Russian River near Hopland. _ _

Page

26

27

29

TABLES

Page 

TABLE 1. Mean monthly distribution of precipitation at selected

stations.________^_________________________________ 36

2. Mean annual precipitation for period 1931-63 at stations

in north coastal California.____ ______________________ 36

3. Hydrologic budget for watersheds upstream from key

stream-gaging stations, for base period 1931-63_______ 37

4. Bar chart of records for stream-gaging stations in north

coastal California___________________________________ 39

5. Flow-duration summary of daily discharge for selected

stream-gaging stations_____-__-___---_-_-_--_-_______ 41

6. Mean monthly distribution of runoff at selected gaging

stations._ ________________________________________ 48

7. Low-flow frequency table for selected stream-gaging

stations.________ __________________________________ 48

8. Composite low-flow frequency table_____________________ 52

9. Summary of results of flood-frequency analysis.__________ 53

10. Multiple-regression equations and associated statistics for

peak discharges at selected recurrence intervals_______ 54

11. Comparison of maximum recorded peak discharge and QS o

computed from regression equation ___._._____._._____ 55

12. High-flow frequency data for selected stream-gaging

stations.__________________________________________ 57

13. Multiple-regression equations and associated statistics for 

high flows of various durations at selected recurrence 

intervals_____________ ._ ._ ________________________ 60
SURFACE-WATER HYDROLOGY OF CALIFORNIA COASTAL

BASINS BETWEEN SAN FRANCISCO BAY AND

EEL RIVER

By S. E. KANTZ and T. H. THOMPSON

ABSTRACT

This report presents an analysis of the surface-water hydrology of the coastal 

basins of California that lie between the north shore of San Francisco Bay and 

the south boundary of the Eel River basin. Its purpose is t<? provide hydrologic 

information in convenient form for use in project planning by the California 

Department of Water Resources and other water agencies operating in the 

State.

The report area, comprising about 5,000 square miles, lies wholly within the 

northern California Coast Ranges (physiographic section). Most of the streams 

are small and drain watersheds of less than 100 square miles. A notable exception, however, is the Russian River, which has a drainage area of almost 

1,500 square miles.

Precipitation is distinctly seasonal, and very little occurs from June through 

September. About 80 percent of the total precipitation falls during the 5 

months November through March. Mean annual precipitation increases from 

south to north and is strongly influenced by the altitude, shape, and steepness 

of mountain slopes. Mean annual precipitation ranges from a low 20 inches 

in the Napa Valley to a high of 110 inches on the mountain divide of the Mattole 

River basin. Snow has an insignificant influence on the hydrology of the region.

Average annual natural runoff from the region is about 5.5 million acre-feet, 

which is equivalent to about 21 inches from the entire region. Runoff, however, 

has an areal distribution similar to that of precipitation and ranges from 

about 5 inches in the south to about 85 inches in the north. About 80 percent 

of the runoff occurs during the 4 rainy months December through March. The 

rains of November, falling on rather dry ground, generally contribute little 

runoff. Flow in the summer and early fall is poorly sustained, and many of 

the smaller streams go dry. This seasonal distribution of runoff reflects not 

only the seasonal distribution of precipitation but also the influence exerted by 

the geologic characteristics of the California Coast Ranges. The low permeability of the soil and surficial rock and the limited capacity for subsurface storage 

impede infiltration, and as a result there is little lag between rainfall and runoff.

Study of the runoff regimen indicates that, for any stream, there is a close 

relationship between the flow-duration curve and the frequency curves for low 

flows of various durations. Both are influenced by basin characteristics, and 

the relationship is maintained by the regional consistency of the seasonal pattern 

of precipitation. The recurrence intervals of low flows sustained for periods 

ranging from 1 day to 274 days may be derived from the flow-duration curve

1
2 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

with considerable confidence. The characteristics of the flow-duration curve 

were found to be roughly related to mean discharge.

Seven major floods have occurred in the region in the past 25 years. In many 

of the coastal basins south of the Russian River, six of the seven floods were of 

nearly equal magnitude. In the Russian River basin the flood of December 

1964 was generally the maximum of these events, but in the coastal basins north 

and west of the Russian River the flood of December 1955 generally produced the 

greatest peak discharges. A flood-frequency study of the region indicates that 

the magnitude of floods of any given frequency can be related to size of drainage 

area and to mean annual basinwide precipitation. This precipitation is an 

excellent index of the relative magnitude of storms of any given frequency 

because the bulk of the precipitation occurs during several general storms each 

year, and the same number of general storms occur at all stations in any given 

year.

The magnitude and frequency of high flows, for durations ranging from 1 day 

to 274 days, were analyzed by a method that closely paralleled that used in 

the flood-frequency study. Average discharges for each selected duration and 

frequency were correlated with drainage area and mean annual basinwide precipitation. Results were highly satisfactory because all correlations had coefficients of multiple correlation that were equal to or greater than 0.99.

INTRODUCTION 

PURPOSE AND SCOPE

This report on the surface-water hydrology of coastal basins in 

northern California has been prepared to provide hydrologic data for 

use in project planning by the California Department of Water Research and by other water agencies operating in the State. The broad 

objective of this project planning is the full conservation, control, 

and utilization of the water resources of California to meet future 

water needs.

The region studied has an area of 5,000 square miles and comprises 

the coastal drainage basins that lie between the north shore of San 

Francisco Bay and the south boundary of the Eel River basin. (See 

fig. 1.) The average annual runoff from the area is about 5.5 million 

acre-feet; the estimated ultimate water requirement of the area (California Water Resources Board, 1955) is 1.4 million acre-feet annually. 

Although runoff within the area varies greatly from basin to basin, the 

large total volume is indicative of a more-than-adequate water supply 

for the region. The bulk of the runoff, however, occurs in the winter, 

when the need for water is least. Consequently, there is a need for 

storage facilities to overcome the difference in time between periods 

of abundant supply and heavy demand for water, to provide flood 

control, and to enhance fishlif e and the recreation potential of the region. A prerequisite, however, to the planning for full development 

of the water resources of the region is a detailed inventory of the water 

supply, covering the distribution of runoff with respect to both area
42

INTRODUCTION

124' 123' 122' 12f 120*

33" -33"

120* 119' 118°

i;7« 116' 115*

0 100 MILES

FIGUKE 1. Location of report area (shaded).

and time. This report is directed toward filling the need for that inventory. The great mass of surface-water data compiled by the U.S. 

Geological Survey has been analyzed. These data have been published 

in the water-supply paper series titled "Surf ace-Water Supply of the 

United States, Part 11, Pacific Slope Basins in California," and, since 

1961, in an annual report series titled "Surface Water Records of California." The results of the study are reported in this paper.

A 33-year base period, 1931-63, has been used in this report for 

studying the hydrologic budget (mean annual precipitation, runoff, 

and water loss) of watersheds upstream from key gaging stations. 

Three factors influenced the selection of this base period: (1) No stations on natural streams in the region have records for more than 33 

years; (2) rainfall records suggest that the average annual runoff for 

the period 1931-63 closely approximates the long-term mean annual 

runoff; (3) this 33-year base period includes years of extreme drought
4 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

and severe flooding. (Unless otherwise specified, year is used in this 

report, to refer to the water year, a 12-month period ending September 30. The water year is commonly used in water-supply studies and 

is designated by the calendar date of the last 9 months of the period; 

for example, the period October 1,1951, to September 30,1952, is designated the 1952 water year.)

The regimen of the various streams is discussed in the report and is 

analyzed in studies of flow duration, flood frequency, and frequency 

and duration of sustained high and low flows. For all these aspects of 

the hydrology of the study area, except flood frequency, the latest data 

used were those for the 1963 water year. However, before this report 

was completed the disastrous floods of December 1964 occurred, and 

the time base of the flood-frequency analysis was extended to include 

this major event.

Few stream-gaging stations were operated during all years of the 

base periods used in this report, and it was necessary, therefore, to resort to correlation techniques to produce synthetic streamflow figures 

to fill existing gaps in the records. Greater refinement in these correlative estimates of flow would have been possible if this study had 

been postponed for several years to permit the collection of additional 

data. The pressing need of the planning agencies, however, for information of the type presented in this report permitted no delay.

OTHER INVESTIGATIONS

Shortly before this study was completed, a report on the water 

resources and future water requirements of north coastal California 

was published by the California Department of Water Eesources 

(1965). That report discusses not only most of the present report 

area but also many of the coastal basins to the north that were treated 

in an earlier U.S. Geological Survey report (Eantz, 1964). The 

scope of the State report is much broader than that of the Geological 

Survey reports, and although there is some duplication in the reports 

of the two agencies, they in general complement each other. The 

Geological Survey reports stress frequency studies and regional 

relationships that deal with the regimen of streamflow. These 

relationships enable the runoff characteristics of ungaged streams in 

the area to be deduced. The State report is more strongly projectoriented, to meet the immediate needs of the Department of 

Water Resources.

The ground-water resources of the report area have been studied 

in recent years, and the results of the investigations have been 

published in three US. Geological Survey water-supply papers 

(Cardwell, 1958, 1965; Kunkel and Upson, 1960). A summary of
DESCRIPTION OF REGION 5

ground-water conditions is given in the report of the California 

Department of Water Resources (1965).

The quality of water in the region has also been investigated. 

Information concerning surface-water quality is published by the 

U.S. Geological Survey in its water-supply paper series titled 

"Quality of Surface Waters of the United States, Parts 9-14." The 

California Department of Water Resources publishes information 

relating to the quality of both surface and ground water in its annual 

Bulletin 65 series titled "Quality of Surface Waters in California," 

and Bulletin 66 series titled "Quality of Ground Waters in California." There is no duplication of quality-of-water data in the 

Geological Survey and State reports.

ACKNOWLEDGMENTS

This study was made under the terms of a cooperative agreement 

between the U.S. Geological Survey and the California Department 

of Water Resources. The report was prepared by the Geological 

Survey under the supervision of Walter Hofmann, district chief of 

the Water Resources Division.

Acknowledgment is made of the assistance given by the California 

Department of Water Resources, Sacramento, Calif., in furnishing 

information on consumptive use of water in the region. Runoff data 

for the ungaged Lagunitas Creek basin in Marin County were obtained through the courtesy of the Marin Municipal Water District.

DESCRIPTION OF REGION

Most streams in the report area are small and drain watersheds of 

less than 100 square miles. A notable exception, however, is the Russian River, which has a drainage area of almost 1,500 square miles. 

This drainage basin and other comparatively large basins in the region are delineated on plate 1. The region is mountainous except for 

about 550-square miles of relatively flat area, 45 percent of which lies 

in the Russian River basin and the remainder in the lower part of the 

basins tributary to San Francisco Bay. (The term "relatively flat," 

as used here, refers to a land slope of less than 200 ft to the mile.) 

The principal watershed divides range generally from 2,000 to 3,000 

feet in altitude, but there are a few isolated peaks that exceed 4,000 

feet. The mountainous areas are well covered with timber, and lumbering is the principal industry.

GEOLOGY AND PHYSIOGRAPHY

The study area lies wholly within the northern California Coast 

Ranges physiographic section (Fenneman, 1931). The rocks of the

258-151 67 2
6 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

northern California Coast Eanges consist chiefly of an inadequately 

mapped and poorly understood assemblage containing mostly sandstone and shale, with minor altered basalt and chert, which together 

compose the Franciscan Formation of Jurassic and Cretaceous age 

(Bailey and others, 1964). The rocks are locally intruded by sill-like 

masses of ultramafic rock that is now largely altered to serpentine. 

Volcanic rocks, ranging in age from Pliocene to Recent and in composition from basalt to rhyolite, overlie the Franciscan rocks in the 

mountains between Clear Lake and the San Pablo embayment of San 

Francisco Bay. The Franciscan rocks and, to a much lesser degree, 

the younger volcanic rocks, are folded and faulted so that their erosion 

has yielded a northwest-trending series of ridges and valleys. Some 

of the valleys are broad and flat because they contain thick deposits of 

gravels derived from the erosion of the surrounding mountains; others 

are narrow because they are still being actively eroded and contain 

almost no gravel. Because many of the valleys follow zones of brecciated rock along major faults, hummocky topography and landslides 

are prominent features of the landscape.

The major drainage of the area is provided by the Russian River, 

whose valley trends eastward from Jenner, on the coast, through the 

coastal mountains to Healdsburg, where it bifurcates into a long northwest-trending branch and a short southeast-trending branch. South 

of Healdsburg, parallel ranges separate the longitudinal valleys of the 

Napa River, Sonoma Creek, and Petaluma River; the Petaluma River 

valley is the southern extension of the Russian River valley. Extending northwest of Healdsburg and forming a narrow belt between the 

Russian River and the coast, is the Mendocino Plateau. It is a submaturely dissected upland rising from about 1,600 feet on the west to 

2,100 feet on the east (Fenneman, 1931). The Mendocino Plateau is 

drained westward by the Gualala, Navarro, and Mattole Rivers, and 

other shorter transverse streams; but in a part near the coast, the South 

Fork Gualala River and a reach of the Garcia River have longitudinal 

trends where they flow in the rift valley of the San Andreas fault. 

North of the 39th parallel the ranges form a broad mountainous belt 

with only scattered alluvial-filled valleys.

CLIMATE

Climatologists and geographers have classified the climate of the 

study area as Mediterranean because of its mild wet winters and cool 

dry summers. Along the coast the climate is marked by moderate and 

equable temperatures, heavy and recurrent fogs, and prevailing west 

to northwest winds. Inland, temperatures have a wider range and 

winds are generally moderate. Temperatures are influenced largely
DESCRIPTION OF REGION 7

by altitude and by local topography. Precipitation is likewise orographically influenced and decreases generally from north to south. 

Precipitation is distinctly seasonal, and very little occurs from June 

through September. The seasonal distribution of precipitation is 

largely controlled by the anticyclonic cell that is normally present off 

the California coast, particularly in summer. The frequent winter 

precipitation generally occurs when this anticyclone either is absent 

or is far south of its usual summer position. Snow occurs in moderate 

amounts at altitudes above 2,000 feet but rarely remains on the ground 

for long periods of time, and it has little or no influence on the regimen 

of runoff.

DESCRIPTION OF THE INDIVIDUAL BASINS 

NAPA RIVER BASIN

The Napa Eiver heads on the south flank of Mount Saint Helena, 

flows southeastward for about 40 miles, and empties into San Pablo 

Bay. Its principal tributaries are Conn, Dry, Milliken, and Redwood 

Creeks, all of which enter the river in a 10-mile reach upstream from 

the city of Napa. The central alluvial plain of Napa Valley is about 

30 miles long and ranges in width from less than 1 mile at the north 

end to nearly 4 miles just north of Napa. The basin is not gaged 

downstream from Napa because the city is at the head of tide and 

because there is little accretion to the flow of the river downstream 

from, the city. This study of the hydrology of the Napa River basin 

is therefore confined to the drainage area of 230 square miles upstream 

from Napa.

The principal use of water in the basin is for municipal and domestic purposes and for the irrigation of about 2,500 acres of agricultural land in Napa Valley. The principal towns in the valley are 

Napa, St. Helena, and Calistoga. Prior to 1945 almost all water was 

obtained from wells. The only surface-water supply of note was Milliken Creek, on which, in 1924, the city of Napa constructed a reservoir having a capacity of 2,000 acre-feet. The supply, however, failed 

to keep pace with expanding demands, and in 1945 the city built Conn 

Dam on Conn Creek. The impounding reservoir, Lake Hennessey, 

which has a capacity of 31,000 acre-feet, became the chief element in 

the water supply for the city of Napa. In subesequent years the municipal systems of the towns from St. Helena south and many ranches 

made connections to the pipeline from Lake Hennessey. The only 

other major surface-water reservoir in the basin is on Rector Creek, 

a tributary of Conn Creek. Rector Creek is the source of supply for 

Yountville Veterans Home and Napa State Hospital.
8 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

All streams tributary to the ISTapa Kiver go dry in summer. ISTapa 

Eiver is a perennial stream at the St. Helena gaging station but is 

usually dry at the Napa gaging station for one or more months during 

the summer. This loss in streamflow between the two gaging stations 

is attributed to pumping for irrigation both from the stream and from 

the ground-water reservoir.

SONOMA CREEK BASIN

Sonoma Creek heads on the west side of the Mayacmas Mountains, 

flows southeastward for about 28 miles, and empties into San Pablo 

Bay. The gaging station farthest downstream in the basin is at Boyes 

Hot Springs, 1.5 miles north of the city of Sonoma; only the 62-squaremile drainage area upstream from this gage is considered in this study. 

The alluvial plain in this basin extends north from Boyes Hot Springs 

for about 4 miles and is about 1 mile wide. The only tributary stream 

of appreciable size is Calabazas Creek, which enters Sonoma Creek 

at Glen Ellen.

The principal use of water in the basin is for municipal and domestic 

purposes and for the irrigation of about 500 acres of agricultural land. 

Almost all water is obtained from wells, but in 1963 importation of 

supplemental water from the Eussian Eiver began. At present (1964) 

the area served with Eussian Eiver water is small, but it is expected 

to increase rapidly.

PETAI/TJMA RIVER BASIN

The Petaluma Eiver has its source about 1 mile south of Cotati, on 

the south side of the low divide (altitude of less than 500 ft) that 

separates Petaluma Eiver drainage from Eussian Eiver drainage. 

The river flows southeastward for about 23 miles and empties into San 

Pablo Bay. The single gaging station in the basin is 1 mile upstream 

from Petaluma, the only urban center in the basin. This report is 

concerned only with the 31-square-mile drainage area upstream from 

the gage. The alluvial plain in this basin comprises about 20 square 

miles and has a maximum width of about 3% miles at the gaging station. The tributary streams are small; Lichau Creek is the largest 

one upstream from Petaluma.

The principal use of water in the basin is for domestic and municipal purposes and for the irrigation of about 200 acres of agricultural 

land. Water is obtained from wells and small streams diversions. 

Since 1962 the city of Petaluma has imported more than half its water 

supply from the Eussian Eiver.

MARIN COUNTY BASINS

The principal streams in Marin County are Novato, Corte Madera, 

Lagunitas, and Walker Creeks.
DESCRIPTION OF REGION 9

Novato Creek flows eastward in a valley adjacent to Petaluma Valley and empties into San Pablo Bay. The only gaging station in the 

basin is on Novato Creek 1 mile west of Novato, the single urban center 

in the basin. This report deals with the 17.5-square-mile drainage 

area upstream from the gage. The only significant use of water in this 

basin is related to the operation of Stafford Lake, a 4,500-acre-foot 

reservoir on Novato Creek upstream from the gage. Since early 1952, 

when the reservoir was completed, water has been diverted from Stafford Lake for municipal use in Novato. Since 1961, part of the water 

needs of the town have been met by importation of water from the 

Russian River.

Corte Madera Creek flows southeastward through a highly urbanized 

valley in southeastern Marin County and empties into San Francisco 

Bay. The principal water use in the basin is for domestic and municipal purposes. The single gaging station in the basin is 4 miles from 

the mouth of the creek and gages the runoff from a drainage area of 

18 square miles; flow is partly regulated by Phoenix Lake, a reservoir 

whose capacity is 612 acre-feet.

Lagunitas Creek heads on the north slope of Mount Tamalpais at 

an altitude of about 2,300 feet, flows northwestward along the base 

of Bolinas Ridge, and empties into Tomales Bay. The stream has a 

steep gradient in its upper reaches it falls 1,500 feet in iy2 miles. 

It is joined by its principal tributary, Nicasio Creek, about 4 miles 

from its mouth; another large tributary, Olema Creek, joins Lagunitas 

Creek about 1 mile from its mouth. The total drainage area of the 

Lagunitas Creek basin is about 80 square miles. The streams in the 

basin are highly regulated by four reservoirs Laguiiitas Lake, Bon 

Tempe Lake, Alpine Lake, and Kent Lake on Lagunitas Creek, and 

Nicasio Reservoir on Nicasio Creek. Nicasio Reservoir was completed 

in 1961. The five reservoirs are operated for municipal and domestic 

supply by the Marin Municipal Water District, and they have a combined capacity of 52,500 acre-feet. The only streamflow records obtained in the basin by the U.S. Geological Survey were from a gage 

on Nicasio Creek at the site of the present reservoir. This station was 

operated during the period 1954-60.

Walker Creek heads 011 the west slope of the divide that separates 

its drainage from that of Novato Creek. Walker Creek flows northwestward for 16 miles through rough mountainous terrain and then 

westward for 7 miles through gently rolling country; it empties into 

Tomales Bay. The principal tributaries are Chileno Creek and 

Arroyo Sausal. The basin is sparsely populated, and there is little 

irrigation. The principal economic activity is dairying in the Chileno 

Creek subbasin. The only streams in the basin that have been gaged
10 SURFACE WATEB, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

are Arroyo Sausal and Walker Creek above the mouth of Chileno 

Creek.

RUSSIAN RIVER BASIN

The Eussian Eiver drains an area of 1,485 square miles that is approximately 100 miles long and from 12 to 32 miles wide. From its 

source, about 16 miles north of Ukiah, the river flows southward for 

90 miles through Redwood, Ukiah, Hopland, and Alexander Valleys, 

and through the northwestern part of the Santa Eosa Plains. The 

river then turns abruptly westward at Mirabel Park and flows for 22 

miles through a canyon in the mountains before entering the Pacific 

Ocean at Jenner. The several alluvial valleys through which the river 

flows are separated by mountain gorges. Altitudes in the basin range 

from 4,480 feet to sea level. The principal tributaries of the Eussian 

Eiver are East Fork, Sulphur Creek, Maacama Creek, Dry Creek, and 

Mark West Creek. The principal tributary of Mark West Creek is 

Laguna de Santa Eosa, which drains a large flat marshy area and 

enters Mark West Creek about 5 miles upstream from its mouth. The 

flow in the lower reaches of Mark West Creek reverses during periods 

of medium and high stage on the Eussian Eiver. At those times Eussian Eiver water enters Mark West Creek, flows into Laguna de 

Santa Eosa, and spreads over the surrounding lowlands. These lowlands, when inundated, act as a natural detention basin and thereby 

reduce peak discharges on the lower reaches of the Eussian Eiver.

The principal use of water in the basin is for the irrigation of about 

36,000 acres of agricultural land; it is also used for municipal, domestic, and industrial purposes, notably in the communities of Ukiah, 

Cloverdale, Healdsburg, Santa Eosa, and Sebastopol. Evapotranspiration from the irrigated areas accounts for most of the water 

actually consumed.

Several major water developments have been made in the Eussian Eiver basin. The Pacific Gas and Electric Co. annually diverts 

about 150,000 acre-feet of Eel River water into the East Fork Eussian 

Eiver through its Potter Valley diversion tunnel and powerplant 

northeast of Ukiah. This diversion, which began in 1908, is now regulated by storage in Lake Mendocino, a flood-control and waterconservation reservoir that was built in 1959 on the East Fork Eussian 

Eiver near its mouth. Lake Mendocino has a capacity of 122,500 

acre-feet. Its releases maintain runoff on the main stem of the Eussian 

Eiver during the dry season to satisfy irrigation and water-supply 

requirements downstream. This is done by maintaining a minimum 

flow of 125 cfs (cubic feet per second) at the Geological Survey gage 

near Guerneville, 74 miles downstream from the mouth of the East 

Fork.
PRECIPITATION 11

At a site on the Russian River just upstream from the mouth of 

Mark West Creek (3 miles upstream from the Guerneville gage), 

the Sonoma County Flood Control and Water Conservation District 

diverts water for municipal use in the cities of Santa Rosa and 

Forestville within the Russian River basin and for other towns outside the basin. This diversion, which began in 1959, increased from 

6,600 acre-feet in 1959 to 12,000 acre-feet in 1964. Water for this 

diversion is pumped from a gallery 60 feet beneath the streambed.

Some water is also diverted from Copeland Creek 9 miles south of 

Santa Rosa. This water is exported outside the Russian River basin to 

Petaluma in amounts of less than 100 acre-feet annually.

To meet the increasing water needs in the basin, construction has 

been authorized for a flood-control and water-conservation reservoir 

on Dry Creek near the Geyserville gaging station. The authorized 

capacity of the reservoir is 277,000 acre-feet. This volume of storage 

would provide an increase of about 90,000 acre-feet in the annual 

water supply available to the lower basin for municipal use and for 

such industrial uses as processing lumber, agricultural, and dairy 

products.

SMALL, BASINS IN SONOMA, MENDOCINO, ANI> HUMBOLDT COUNTIES

Many small coastal streams north and west of the Russian River 

basin drain the Mendocino Plateau. The principal ones are the Gualala, Navarro, Noyo, and Mattole Rivers. Virtually the entire area 

is mountainous; the principal ridges range in altitude from 2,000 

feet in the south to 3,000 feet in the north. The mountainous parts are 

well covered with timber, and lumbering is the principal industry. 

Some crops are raised in the small valleys, but dairying and sheep 

raising are of greater commercial importance. Of the 2,100 square 

miles in the area, only about 500 acres is irrigated, and most of this 

acreage is near Boonville, in the Navarro River basin. Commercial 

fishing is centered in the vicinity of Fort Bragg. This city, which had 

a population of 4,430 in 1960, is the largest in this part of the report 

area. Utilization of the available water resources is almost negligible 

in this sparsely populated area.

PRECIPITATION

Precipitation in the report area is distinctly seasonal about 80 

percent of the total occurs during the 5 months November through 

March. The distribution of annual precipitation is shown in table 

1, which gives mean monthly precipitation, in percentage of the total, 

at four representative stations in the region. The bulk of the precipitation occurs during moderately intense general storms of several 

days duration. Hourly precipitation in excess of 1 inch is uncommon.
12 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

Snow falls in moderate amounts at altitudes above 2,000 feet, but it 

seldom remains on the ground for more than a few days.

Mean annual precipitation generally increases from south to north 

and is strongly influenced by the altitude, shape, and steepness of 

mountain slopes. The isohyetal map on plate 1 presents a generalized 

picture of the areal distribution of mean annual precipitation during 

the 33-year period 1931-63. The wide range in mean annual precipitation is striking; precipitation decreases from 110 inches in the 

north to 20 inches in the south. Plate 1 also shows the location of the 

43 U.S. Weather Bureau precipitation stations whose records were 

used in the construction of the isohyetal map; precipitation stations 

outside the region, whose records were used, are not shown. Table 2 

lists mean annual precipitation at each of the 43 stations for the base 

period 1931-63. (Correlation procedures have been used, where necessary, to adjust station records to the base period.)

Annual precipitation varies greatly from year to year at any particular station. For example, at Fort Bragg the mean annual rainfall 

for the period 1931-63 was 37.9 inches, but during that period annual 

precipitation ranged from 19.8 inches in 1931 to 60.3 inches in 1941. 

Time trends in precipitation are illustrated by graph A of figure 2 

which shows accumulated departures of annual precipitation from the 

68-year mean at Fort Bragg during the period 1896-1963. The progression shown is typical of that for the entire report area. In a graph 

of this type, the plotted position for any particular year has little 

significance, and only the slope of the curve is important. A downward slope indicates less than average precipitation; an upward slope 

indicates that precipitation exceeded the mean. The graph shows that 

northern California underwent a prolonged wet period from 1900 to 

1916, followed by a dry period from 1917 to 1937. The 26 years since 

1937 have been predominantly wet. The driest single year in the 68 

years of record was 1924, when the annual precipitation totaled 16.6 

inches; 1931 was the second driest year. The wettest single year of 

record was 1941. During the base period (1931-63), chosen for use 

in this report, the mean annual precipitation at Fort Bragg differed 

by only 0.7 percent from the mean for the entire 68 years of record 

at that station.

Mean annual basinwide precipitation has been estimated from the 

isohyetal map on plate 1 for the larger watersheds in the area and for 

those watersheds having a potential for development. The watersheds 

considered are upstream from the stream-gaging stations listed in 

table 3; these stations can be located on plate 1 by their identifying 

numbers. Estimates of basinwide precipitation obtained from the 

existing network of precipitation stations are not precise because of the
ACCUMULATED DEPARTURES FROM MEAN, IN P

o >O
14 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

mountainous nature of the terrain. The estimates are useful, nevertheless, as indexes of precipitation. The basinwide averages are given 

in table 3.

RUNOFF

MEAN ANNUAL VOLUME

Mean annual runoff in the report area is directly related to mean 

annual precipitation and is influenced principally by (a) latitude, 

(b) distance from the ocean, (c) altitude and steepness of the 

mountain slopes, and (d) exposure and orientation of the mountain 

slopes. Thus, mean annual runoff tends to increase from south to 

north. The Mattole River basin, in the north end of the report area, 

has an average annual runoff of 67.7 inches, or the largest annual 

volume of runoff per square mile of any of the basins studied.

Runoff trends during the period 1931-63 are illustrated by graph 

(B) of figure 2, which shows accumulated departures of annual 

runoff from the 33-year annual mean for Napa River near St. Helena. 

This 33-year period is the longest practicable for studying long-term 

runoff trends for the area (p. 3). The trends depicted are similar 

to those shown by the precipitation graph (A) for Fort Bragg. 

The driest single year of record was 1931, when runoff was generally 

about 15 percent of the 33-year mean. The driest 5-year period of 

record was 1931-35, when runoff was about 50 percent of the longterm mean. The wettest year of record was 1956, when runoff was 

more than twice the 33-year mean.

Plate 1 shows the location of the 63 stream-gaging stations in the 

area for which runoff data have been compiled. The stations are 

numbered in downstream order using the permanent numbering 

system adopted by the U.S. Geological Survey in 1958. The stations 

identified by a symbol as being partial-record stations, are sites where 

discharge measurements of either low flow or both low flow and peak 

discharge, were systematically made. Stations where only one 

annual measurement of minimum or maximum discharge.was made 

are not shown. Table 4 lists the 63 gaging stations, with their 

drainage areas and identifying numbers (pi. 1), and also presents a 

bar chart showing the period of record at each station.

Table 3 lists estimated mean annual natural runoff from basins 

upstream from key stream-gaging stations for the period of 1931-63. 

The runoff figures have been adjusted, where necessary, for the effect 

of manmade changes in stream regimen. For example, the construction of a reservoir upstream from a gaging station distorts the record 

of runoff because of evaporation losses and the varying volumes of 

stored water. Diversion of either surface or ground water for irri-
RUNOFF 15

gation, domestic, or industrial use likewise affects the runoff record. 

Where the diverted water is used upstream from the gaging station, 

the figure for natural runoff in table 3 includes only that part of 

the diverted water that is lost through evapotranspiration; the 

remainder is assumed to return eventually to the stream or effluent 

ground-water body. Table 3 lists average annual consumptive use 

of applied water in areas upstream from the key gaging stations. 

Because consumptive use has increased through the years, the average 

annual consumptive use is less than the present use (1964), and for 

this study it was assumed to equal two-thirds of the present use. 

The figures for consumptive use in table 3 are crude approximations, 

but they are considered satisfactory for this study because they 

represent only a small part of the natural runoff.

The 33-year average annual runoff figures in table 3 have been 

obtained by a series of runoff correlations involving short-term 

stations with longer records. Some of the short-term stations used 

have been in operation only a few years. Runoff estimates, however 

carefully made, that are based on short periods of observation are subject to considerable error, but their inclusion is justified because the 

records are needed now for use in preliminary project planning.

AVERAGE ANNUAL WATER LOSS AND EVAPORATION FROM 

WATER SURFACES

As considered in this report, the average annual water loss from a 

drainage basin is the difference between the 33-year mean annual precipitation over the basin and the 33-year mean annual runoff. The use 

of long-term average figures in this computation minimizes the effect 

of changes in surface or underground storage. Computed average 

annual water loss for each watershed under consideration is listed in 

table 3. Because basinwide precipitation totals for the area are considered index figures, rather than absolute values, the computed annual 

water loss figures should also be considered as indexes (of annual 

water loss or evapotranspiration).

Variations in average annual water loss between basins are caused 

by variations in the factors that influence evapotranspiration, namely: 

(1) Temperature and other climatic elements, (2) precipitation, (3) 

soil, (4) vegetation, (5) topography, and (6) geologic factors. The 

climatic factors temperature, humidity, windspeed, and solar radiation fix the upper limit of loss, or the potential evapotranspiration. 

An index of potential evapotranspiration is the evaporation from the 

surface of bodies of water such as lakes and reservoirs. A study by 

the U.S. Weather Bureau (Kohler and others, 1959, pi. 2) produced a 

generalized map of average annual lake evaporation in the United
16 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

States, and a part of this map is reproduced on plate 1. Not enough 

evaporation stations and first-order Weather Bureau stations are present in the area to permit refinement of the isopleths shown. Plate 1 

indicates that lake evaporation, and therefore potential evapotranspiration, increases with distance inland from the humid and often 

foggy coast.

Potential evapotranspiration cannot be attained in a basin unless 

the basin affords the opportunity for evaporation. Evaporation opportunity is related, therefore, to the available moisture supply and is 

influenced laregly by the volume and time distribution of precipitation ; it is influenced to a lesser degree by such basin characteristics as 

soil, vegetation, and geology. Because all watersheds in the study area 

have the same pattern of monthly precipitation and because the annual volume of precipitation is generally equal to or greater than the 

annual value of potential evapotranspiration, variation in average annual water loss in the region is closely related to variation in average 

annual potential evapotranspiration. Inspection of plate 1 and of the 

tabulation of water loss in table 3 shows that average annual water loss 

from any basin in the study area is equal to about six-tenths of the 

average basin wide value of the isopleths of lake evaporation shown on 

the map. Departures from this ratio are to be expected because of 

variability in the factors that influence annual loss, but some of the 

variation undoubtedly results from inaccuracies on plate 1 and from 

discrepancies in the values of water loss computed for this report. 

These discrepancies reflect the complexity of estimating basinwide 

precipitation in mountainous terrain.

FLOW DURATION AND REGIMEN OF FLOW

The basic factors that affect the distribution of streamflow with 

respect to time are topography, tributary pattern, hydrogeology, soil, 

vegetation, and meteorological conditions. The flow-duration curve 

is the simplest means of expressing the time distribution of discharge 

it shows the percentage of time, for a given period, that any specified 

discharge is equaled or exceeded. It thus provides a useful device for 

analyzing the availability and variability of streamflow.

Flow-duration curves of daily discharge were prepared for 23 

gaging stations that have 5 or more years of complete record of daily 

discharge not seriously affected by regulation or diversion. Included 

in the 23 station records are those for stations on the East Fork and 

the main Kussian Kiver for the years prior to regulation by Lake 

Mendocino. The Russian River records were adjusted to natural 

flow conditions by subtracting the measured daily importations of 

Eel River water. Flow-duration curves were also prepared for 10
RUNOFF 17

partial-record stations where low and medium flows have been systematically measured for 5 years. At those 10 stations the measured 

discharges were considered equivalent to daily mean discharges. 

Duration percentages for high flows could not be computed for the partial-record stations, however, because of the lack of high-water data for 

those sites.

The information given by the 33 flow-duration curves is summarized 

in taJble 5, where discharges equaled or exceeded during specified percentages of time are tabulated both in cubic feet per second and in 

cubic feet per second per square mile. All discharges have been placed 

on a common basis for comparison by being adjusted to the base period 

1931-63. To do this, the shorter records were extended by the use 

of correlation procedures. Some personal judgment was required in 

the extrapolation of short-term flow-duration curves to the lower discharges; consequently, the low-flow values given in table 5 are, to a 

considerable degree, subjective estimates. The number of significant 

figures used in the discharge columns of table 5, therefore, do not 

imply great precision; they were included to enable the user of the 

table to conveniently reconstruct smooth flow-duration curves on 

logarithmic normal-probalility paper from the tabulated values.

Duration curves for three gaging stations, selected for broad areal 

coverage in the area, have been plotted on logarithmic normal-probability paper in figure 3. Streamflow is shown as a ratio to mean 

annual discharge to facilitate comparison of the runoff characteristics 

indicated by the curves. Flow-duration curves, however, present 

an incomplete picture of the distribution of discharge, as they ignore 

the chronology of streamflow. The value of a flow-duration curve 

is enhanced, therefore, when it is supplemented by a knowledge of the 

regimen, or time distribution, of flow. The average monthly distribution of runoff in the area is summarized in table 6, which lists 

mean monthly runoff, in percentage of the annual total, at the three 

gaging stations shown in figure 3. The regimen of the Napa Eiver 

near St. Helena (sta. 4560) is representative of streams in the southern 

part of the area, and the regimen of the Mattole Eiver near Petrolia 

(sta. 4690) is representative of those in the northern part.

Examination of figure 3 and table 6 shows that all three streams 

have runoff patterns that are closely similar. Table 6 shows that 

about 80 percent of the runoff occurs during the 4 rainy months December through March. The rains of November, falling on fairly 

dry ground, generaly contribute little runoff. Flow in the summer 

and early fall is poorly sustained, particularly in the southern part 

of the area, where many small streams often go dry. The southern 

basins not only receive the smallest amount of annual precipitation,
18 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

0.2

0.1 

0.08

0.06 

0.05 

5 0.04 

>j 0.03

O 0.02

0.01

0.008

0.006

0.005

0.004

0.003

0.002

O

0.001

\ _________ Napa River near

s \ St. Helena (sta. 4560)

Navarro River near 

Navarro (sta. 4680)

** v

* \ v 

*X **'*\ \

**.\\ Mattole River near 

' \\ """"""""""""""Petrolia (sta. 4690)

\

V

\

\\w

V*-

\ X--.

0.01 0.1 I 5 10 20 30 40 50 60 70 80 v90 95 99 99.9 99.99 

PERCENTAGE OF TIME INDICATED DISCHARGE WAS EQUALED OR EXCEEDED

FIGURE 3. Flow-duration curves of daily discharge for selected gaging stations

for period 1931-63.

but they also are less likely than the northern basins to receive occasional summer and early fall rains. Pumping of water from wells 

and streams is partly responsible for the low summer flow in some 

sectors. In those places, hydraulic continuity generally exists between the stream and adjacent groundwater body, and the natural 

movement of ground water is toward the stream. Wells adjacent to 

the stream channel may temporarily reverse the hydraulic gradient;
RUNOFF 19

wells farther from the channel may intercept water that would otherwise be discharged 'to the stream.

In figure 3, the steep slopes of the three curves show that flow is 

highly variable; that is, the streams have a wide range of discharge. 

This usually indicates that there is little lag between rainfall and 

runoff; in this area this condition is due to the shallowness and low 

permeability of the 'soil and surficial rock, to the absence of lakes or 

large marshy areas, and to the lack of mountain snowpacks where 

precipitation might be stored for delayed runoff. The low-water 

end of the flow-duration curve for Napa River at St. Helena is steeper 

than that of the curves for the other two streams, and this relation 

indicates that low flows of the Napa River are the least sustained of 

the three.

The general characteristics of the flow-duration curves for the 33 

gaging stations can be related to the mean discharges at the stations. 

Key points that were examined on the curves are Qw, $50, $90> Qmea.*, 

and Pmean, where

Q 10=discharge equaled or exceeded 10 percent of the time

during the period 1931-63, 

Q 50=median discharge for the period 1931-63, 

Q 90=discharge equaled or exceeded 90 percent of the time

during the period 1931-63,

Q mean mean discharge for the period 1931-63, and 

P mean=percentage of time, in the 1931-63 period, during which

Q mean was equaled or exceeded.

Values of $10, $50, and $90, are given in table 5; values of $mean are 

given in table 3; and values of Pmean are obtained from the individual 

station flow-duration curves.

In the graphical analyses that follow in figures 4-7, discharges of 

each of the 33 stations are expressed in cubic feet per second per square 

mile. For clarity, identifying station numbers are not shown with the 

plotted points on the graphs.

Figure 4 shows the relation of Pmean to $mean. For the range of mean 

discharge in the area, values of duration time (Pmean) range from 10 

percent of the time for low mean discharge to 22 percent of the time 

for high mean discharge. The values of Pmean offer a comparative 

index to the skewness of the distribution of daily discharges at a station the lower the value of Pmean, the greater the skew in the distribution pf flows. Skewness reflects the fact that much of the runoff occurs 

during rather short periods of high flow. Figure 5 shows the relation 

of $10, $mean, and figure 6, the relation of $5 o, to $mean.

Figure 7, which shows the relation of Q90 to $mean, indicates that 

for mean discharges less than 1.3 cubic feet per second per square
o 

<O M 

 Ors 

fn

Ol
RUNOFF 21

20

a

C/)

a: ui 

a.

a z. 

o 

o

0,6 

0.5 

0.4

0.3 I I I I

I

0.4 0!6 1 2346 

Qmean .IN CUBIC FEET PER SECOND PER SQUA8E MILE

FIGURE 5. Relation of Qv> to Qmean.

mile (940 acre-feet per year square mile), Q90 is usually zero. Q90 is 

a significant index in water resources studies in areas of perennial 

streamflow for example, in the northern part of the study area. In 

such places Q90 is often considered an appropriate measure of the 

quantity of water available for continuous use, without resorting to 

surface storage and without permanently depleting water in underground storage.

The scatter of plotted points on the graphs in figures 4-7 indicates 

that for the percentile flows investigated, only a part pf the variation 

in discharge is explained by variation in mean discharge. A large

258-151 67 4
22 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF. 

1.0

f

0.001

0.4 0.6 1 2346 

Q mean. IN CUBIC FEET PER SECOND PER SQUARE MILE

FIGURE 6. Relation of QK> to Qm..B
Qgo, IN CUBIC FEET PER SECOND PER 

pop

2

b 

CD 

TO

s *

n

01
24 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

part of the variation in Q50 and Q90 is related to. variation in the geology of the basins, and, consequently, there is relatively poor correlation 

with $mean alone. Nevertheless, figures 4-7 are helpful in providing 

a generalized picture of the characteristics of flow-duration curves in 

the report 'area.

Although it is common practice to compute indexes of streamflow 

variability when analyzing the characteristics of flow-duration curves, 

it was not done for this report. An index of variability, such as that 

introduced by Lane and Lei (1950) or that used by Eantz (1964, p. 

43-45), is significant for perennial streams but is meaningless for 

streams that go dry or for streams of highly variable discharge whose 

low flows are minute. Many streams in the southern part of the 

area are not perennial, so the computation of index figures of variability was not warranted.

LOW FLOW MAGNITUDE, DURATION, AND 

FREQUENCY

A prerequisite for any study involving water supply during periods 

of critically low runoff is a knowledge of the magnitude, duration, and 

frequency of deficient flow. To fill the need for this information, lowflow frequency graphs and tables were prepared for 31 sites to show 

the probable recurrence interval of low flows of various magnitudes and 

durations. The 31 sites included all 23 complete-record gaging stations 

and 8 of the 10 partial-record stations that were used in the flow-duration analysis. The gaging stations are those having 5 or more years 

of discharge record that was not seriously affected by regulation or 

diversion, or having a discharge record (such as that for the Russian 

River stations) that could be adjusted to natural flow conditipns from 

a record of measured diversions. The duration periods used in this 

analysis were 1, 7, 14, 30, 60, 90, 120, 183, and 274 days. A 3-day 

duration period was not included because the lowest mean discharge 

for 3 consecutive days during each year was almost identical with the 

minimum daily discharge of «ach year. The base period used was 

April 1,1931, to March 31, 1963. Using March 31 as the closing day 

of each year eliminated the possibility of a period of sustained low flow 

starting in one year and extending into the next.

Low-flow frequency graphs for a gaging station were constructed 

by applying the following procedure:

1. The smallest mean discharges of each year for each of the nine duration periods (1, 7,14 ... 274 days) were listed and ranked in ascending order of magnitude, starting with "1" for smallest discharge in the array.
LOW FLOW MAGNITUDE, DURATION, AND FREQUENCY 25

2. The plotting position of each discharge was computed by use of 

the formula

Recurrence interval = N+l

M

where N is the number of years of record (32 yrs), and M is the 

rank or order number.

3. The discharges and their corresponding recurrence intervals were 

plotted on logarithmic extreme-value probability paper, and 

smooth curves were fitted to the plotted points.

Because no station in the report area had a complete array of dischare data for the 32-year base period, it was necessary to estimate 

many of the discharges needed for the analysis. In making these estimates, discharges at each gaging station for each of the nine duration 

periods were correlated graphically with concurrent discharges at a 

nearby station in or near the report area. It was practical to include 

8 of the 10 partial-record stations in this analysis because their 

periodically measured discharges correlated linearly with discharges 

at complete-record gaging stations, and therefore the correlation equations were valid for discharges averaged over each of the 9 duration 

periods. The two remaining partial-record stations Garcia River 

near Point Arena and Greenwood Creek at Elk were not used because 

their discharges did not correlate linearly with those for nearby complete-record stations.

Figure 8 is an example of the low-flow frequency curves derived in 

this study; the flat roughly parallel curves are typical of those for 

streams in the northern, or more humid, part of the report area. The 

nine low-flow frequency curves for streams in the southern, or less 

humid, part of the area are much steeper because the low flows of these 

streams are poorly sustained. The spacing of the curves in figure 8 is 

typical, however, of all streams in the area. The curves are closely 

spaced for durations of 1 to 120 days because virtually no runoff-producing rain occurs in the region for at least 4 consecutive months in 

each year. The curves for durations of 183 and 274 days are spaced 

farther apart because these longer durations include periods of storm 

runoff.

Table 7 lists the discharges at each station corresponding to selected 

recurrence intervals on the frequency curves for each of the 31 study 

sites. Personal judgment was required in the extrapolation of discharges to the higher recurrence intervals, and, consequently, the 

smaller discharges in table 7 are rather subjective estimates. The number of significant figures shown in the discharge columns of the table, 

therefore, do not imply great precision, but were included to enable the
26 SURFACE WATEE, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

C/5 u

K ^

Id >

Q. 9

o§

1000

700

500

400

300

200

100

70

50

40

30

20

10

I I 1 I I I I 1 J * 1 1 111 1

J_r

1.02 1.1 1.3 1.5 1.7 2 3; 4 5 7 10 

RECURRENCE INTERVAL, IN YEARS

15 20 25 30 40 50

FIGURE 8. Low-flow frequency carves for Navarro River near Navarro (sta.

4680.)

user of the table to reconstruct smooth low-flow frequency curves on 

logarithmic extreme-value probability paper.

Examination of the low-flow frequency curves and the flow-duration curves indicates that the two sets of data are fairly closely related. 

This is not surprising because all streams in the area have similar regimens. It was possible, therefore, to prepare a composite low-flowfrequency table (table 8) for the area; in this table the discharges are 

replaced by corresponding percentiles from the flow-duration curves. 

For example, table 8 indicates that for any station the 1-day discharge 

with a 10-year recurrence interval is about equivalent to the discharge 

at that station that is equaled or exceeded 99 percent of the time (Qss) . 

To carry this example further, if we check this relationship for Navarro River near Navarro, we find that the 1-day discharge with a 10-
LOW FLOW MAGNITUDE, DURATION, AND FREQUENCY 27

year recurrence interval is 2.9 cfs (from table 7), whereas Q9 » is 3.1 

cf s (from table 5). In general, the composite percentiles listed in table 

8 are slightly smaller than the percentiles for individual stations in the 

northern, or more humid, part of the report area, and somewhat larger 

than the percentiles for individual stations in the southern, or less 

humid, part of the area.

The data in table 7 are in convenient form for use in studies of water 

supply, water power, and pollution control during periods of critically 

low flow, in those situations where the construction of storage facilities 

is not contemplated. Where the need for within-year storage is apparent and economic considerations govern the design of the storage 

facility, the data in these tables may be used to construct a frequencymass curve that represents the total runoff available for a critical period 

of specified recurrence interval. The traditional mass-curve method of 

analyzing the storage required to maintain given draft rates may then 

be applied (Linsley and Franzini, 1964, p. 154-157). An example of this 

method of analysis, shown in figure 9, is self-explanatory. The curve

11,000

10,000

8000

6000

4000

2000

Duration 

period 

(days)

1

7 

14 

30 

60 

90 

120 

183 

274

Mean 

Discharge 

(cfs)

2.5 

2.6 

2.8 

3.1 

3.4 

3.8 

4.8 

12 

37

Total 

runoff 

(cfs-days)

2 

18 

39 

93 

204 

342 

576 

2,196 

10,138

Example: For a 20-year recurrence interval, 

a storage capacity of 1900 cfs-days allows 

a draft of 20 cfs (cubic feet per second)

50 100 150 200 250 

DURATION PERIOD OR PERIOD OF MINIMUM DISCHARGE, IN DAYS

300

FIGURE 9. Frequency-mass curve and storage-draft lines for Navarro River near 

Navarro (sta. 4680) for 20-year recurrence interval. Mean discharge from 

table 7.
28 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

of total available runoff, corresponding to a 20-year recurrence interval, 

is obtained by plotting the volume of runoff, for various durations of 

minimum flow, against the duration period. Water stored in a reservoir 

may be depleted by evaporation or seepage; thus, the amount of storage required for a given draft must be increased accordingly.

FLOOD FREQUENCY

The magnitude and frequency of floods are essential elements in 

studies involving flood-control design or the economics of structures 

within the reach of flood waters. Accordingly, this report provides 

regional flood-frequency relations that may be used as guides in determining "design" flood flows for streams, both gaged and ungaged, 

in the coastal basins discussed in this report. The method of analysis 

used in deriving the regional relationships is only briefly described 

here; it was discussed in detail by Benson (1962) and by Gruff and 

Rantz (1965). The regional concept of flood-frequency analysis is 

used because flood-frequency curves for individual stations, particularly for those stations with short records, are considered inadequate for establishing flood criteria for design purposes. The flood 

series for a single station is a random sample and therefore may not 

be representative of the long-term average distribution of flood events 

at the gaging station.

The stations used in this study were those that had 10 or more years 

of record of momentary peak discharge not seriously affected by regulation or diversion. If a stream, for example, is now regulated by a 

reservoir, but had at least 10 years of record before construction of 

the reservoir, it was included in the analysis; only the years of record 

before construction of the reservoir were used as basic data. For the 

preceding sections of this report, the latest data used were those for 

the 1963 water year. For the flood-frequency analysis, however, the 

time base was extended to include the disastrous floods of December 

1964. The 17 stations listed in table 9 were the only ones in the area 

that met the criterion of 10 or more years of unaffected peak discharge 

record.

METHOD OF ANALYSIS

The first step in the regional analysis of flood frequency was the 

preparation of individual flood-frequency curves for the 17 stations. 

Because a time base of at least 35 years was desired, it was necessary 

to obtain a value of maximum peak discharge at each station for each, 

year of the period, 1931-65. No station had a complete array of 35 

annual peak discharges, and the gaps in the arrays were filled by 

graphical correlation of concurrent peak discharges at nearby stations 

in or contiguous to the report area. At each station the completed
FLOOD FREQUENCY 29

array of 35 peak discharges was ranked in. order of magnitude, 

starting with "1" for the greatest discharge and ending with "35" for 

the smallest. Next, the plotting position or recurrence interval, T7, 

for each discharge was computed by use of the formula :

~ M '

where N is the number of years of record (35 yrs) , and M is the rank 

or order number. Thus, the computed recurrence interval at each 

station for the greatest flood discharge since 1930 was 36 years, a 

value that is consistent with qualitative information concerning historic floods in the region.

Individual station flood-frequency curves were then prepared by 

plotting peak discharge against recurrence interval on extreme- value 

probability graph paper. Only those peak discharges that were observed were plotted ; the peak discharges computed by correlation were 

used only to rank the observed discharges and thereby obtain more 

meaningful values of recurrence interval. A straight line or gentle 

curve was fitted to the plotted points and extrapolated to a recurrence 

interval of 50 years, as shown in the example in figure 10.

The individual flood-frequency curves were used to obtain regional 

flood- frequency equations that relate the peak discharge for selected 

recurrence intervals to basin and climatic parameters. The recurrence 

intervals selected for study were 2.33, 5, 10, 25, and 50 years. The 2.33- 

year recurrence interval was included because of its widespread use 

in statistical analyses of flood frequency that involve the extreme-value

Q 60,000

z 

o 

o

UJ

50,000

40,000

30,000

20,000

£ 10,000

EXPLANATION

o

Years prior to reservoir 

control

Years of reservoir control; 

discharge adjusted for 

regulation by Lake Mendocino

a.oi 1.1 1,2 1.3 1,5 1.7 2.0 2.33 345 7 10 

RECURRENCE INTERVAL, IN YEARS

15 20 25 30 40 50

FIGTJRE 10. Flood-frequency curve for Russian River near Hopland (sta. 4625).
30 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

probability distribution. Investigation of numerous basin and climatic parameters showed the most significant ones to be drainage 

area and mean annual basinwide precipitation. The relation between 

peak discharge and drainage area is obvious in almost all humid environments, the greater the area contributing runoff, the greater the 

peak flow. The relation between peak discharge and mean annual 

basinwide precipitation is less obvious, but it can be explained rationally. Mean annual precipitation is an excellent index of the relative 

magnitude of storms of any given frequency because of the bulk of 

the annual precipitation in the study area occurs during several 

general storms each year, and the same number of general storms 

occur at all stations in any given year. The multiple-regression equations relating peak discharge for each of the five recurrence intervals 

to drainage area and to mean annual basinwide precipitation are listed 

in table 10. The constancy of the exponent of drainage area in the 

equations is noteworthy.

The coefficients of multiple correlation listed in table 10 show a high 

statistical significance and the listed standard errors of estimate are 

reasonably low for a regional flood-frequency study. Table 9 summarizes the results of the analysis. The drainage areas of the stations 

used in developing the regression equations ranged from IT to 1,340 

square miles; mean annual basinwide precipitation ranged from 31 to 

92 inches. Table 9 shows that values of peak discharge computed 

from the regression equations compare reasonably well with those obtained from individual station flood-frequency curves.

APPLICATION OF BEGIONAL FLOOD-FBEQTIENCY BELATIONS

The regional flood-frequency equations that were derived may be 

used to construct flood-frequency curves for ungaged sites or for sites 

with short records of peak discharge in the study area. The first step 

in the process is to determine the drainage area upstream from the site. 

The next step is to obtain the mean annual basinwide precipitation 

from plate 1 of this report. Those values of drainage basin area and 

precipitation are then used in the equations in table 10 to obtain the 

peak discharges corresponding to recurrence intervals of 2.33, 5, 10, 

25, and 50 years. The computed discharges are plotted against recurrence interval on extreme-value probability graph paper, and the 

desired flood-frequency curve is obtained by drawing a smooth curve 

through the plotted points. The regression equations in table 10 

should be used with caution when it is necessary to apply them to 

watersheds whose drainage basin area or mean annual basinwide precipitation lie outside the ranges of values given in the preceding paragraph.
FLOOD FREQUENCY 31 

MAXIMUM RECORDED PEAK DISCHARGES

In this section of the report the maximum recorded peak discharges 

at gaging stations in the study area are examined and compared with 

the theoretical peak discharge for a 50-year recurrence interval as 

computed by the flood-frequency regression equation. In the years 

following 1931, major floods occurred on the following dates: February 1940, December 1955, February 1958, February 1960, February 

1962, January 1963, and December 1964. No single flood of this 

group of seven events produced the maximum recorded peak discharge at all gaging stations in the area. In many of the coastal 

basins south of the Russian River, six of the seven floods were of nearly 

equal magnitude. In the Russian River basin the flood of December 

1964 was generally the maximum event, but in the coastal basins north 

and west of the Russian River the flood of December 1955 generally 

produced the greatest peak discharges.

Another notable flood occurred in northern California in 1937, but 

it has been excluded from this discussion because it was not the maximum event at either of the two stations at which its peak discharge 

is known. At the station on Conn Creek near St. Helena, where 

records of natural flow terminated in 1945 with the construction of 

Conn Dam, the peak discharge of December 1937 was greatly exceeded by that of February 1940. At the station on the Russian River 

near Guerneville, the peak discharge of December 1937 was exceeded 

in four of the seven floods listed above.

Relatively few gaging stations were operated during the entire 

25-year period (1940-64) that includes all seven floods. However, 

because no single flood peak predominated in the entire area, it is 

interesting to examine, with respect to recurrence interval, the maximum peak discharge that occurred at each station whose record includes at least one of the seven floods. Those stations are listed in 

table 11. Stations whose recorded maximum peak discharge was appreciably affected by reservoir regulation have been omitted, but the 

lower Russian River stations were included because their recorded peak 

flows could be adjusted for the effect of regulation by Lake Mendocino.

The maximum discharge ($max) for each of the 37 stations in table 

11 was compared with the theoretical peak discharge for a 50-year 

recurrence interval ($50), as computed from the last equation given 

in table 10. The ratios of $max to $50 are shown in the last column 

of table 11. From qualitative historical records we expect the largest 

flood of the past 25 years to have a recurrence interval of about 35 

years. On the basis of the average slope of the flood-frequency curves 

prepared for this study, the 35-year flood is approximately equal to 

93 percent of Q50. Therefore, we expect the largest flood of the past
32 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

25 years to be roughly equal to 0.93 ($50 ). The ratios of Qma.x to Q5o 

in the last column of table 11 are centered about a value of 0.85, and 

half the ratios lie between 0.65 and 1.05. The results of this comparison are therefore consistent with the assumptions made concerning the 

recurrence interval of maximum observed floods.

HIGH FLOW MAGNITUDE, DURATION, AND 

FREQUENCY

Studies involving the storage of flood waters require a knowledge 

of the magnitude, duration, and frequency of high flows. To fill the 

need for this information, high-flow frequency curves were prepared 

for the 17 stations used in the flood-frequency analysis. The stations, 

listed in table 12, are again those having 10 or more years of discharge 

record that was not seriously affected by regulation or diversion, or 

having a discharge record (such as that for the Russian River stations) that could be adjusted to natural flow conditions from a record 

of measured diversions.

The high flows selected for analysis were the maximum average 

rates of discharge each year for the following duration periods: 1, 3, 

7, 15, 30, 60, 90, 120, 150, 183, and 274 days. The maximum 24-hour 

flow would have been much more significant than maximum flow for 

1 calendar day. The users of Geological Survey streamflow data, 

however, seldom have maximum 24-hour flow rates available to them, 

and, in addition, the maximum flow for so short a time interval is 

generally not a critical factor in reservoir design. For these reasons, 

the rather artificial duration period of 1 calendar day was adopted 

for use in this study. The results obtained for discharge of this duration were surprisingly consistent.

The method of analyzing the high-flow data closely paralleled that 

described in the flood-frequency section of this report. This method is 

most appropriate for use on streams having one major high-water 

period per year, and its principal advantage is that it allows estimates 

of required storage to be made for ungaged streams. In the analysis 

each of the 11 duration periods was studied separately, and the 33-year 

base period October 1930-September 1963 was used. For each station 

and each duration period the data were arrayed in order of magnitude, 

after first filling gaps in the arrays by graphical correlation of concurrent discharges at nearby stations in or near the report area. The 

recurrence interval of each observed discharge in each array was computed and then plotted with its corresponding discharges on extremevalue probability paper, and the plotted points were fitted with a 

straight line or smooth curve.
HIGH FLOW MAGNITUDE, DURATION, AND FREQUENCY 33

The individual-station frequency curves for each of the 11 duration 

periods were used to relate the magnitude of sustained high flows for 

selected recurrence intervals to regional basin and climatic parameters. 

A regional analysis of this type reduces the statistical sampling error 

that might be introduced by treating each station individually in a time 

series. The recurrence intervals selected for study were 2.33, 5,10, 25, 

and 50 years; table 12 lists the discharge indicated by the individual 

station frequency curves for each of these recurrence intervals. The 

basin and climatic parameters selected for correlation with these discharges were drainage-basin area and mean annual basinwide precipitation. These parameters, too, are listed in table 12. The multipleregression equations relating discharge to the 2 parameters for each 

of the 5 recurrence intervals and for each of the 11 duration periods 

are summarized in table 13.

The coefficients of multiple correlation listed in table 13 show an 

extremely high statistical significance, and the listed standard errors 

of estimate are low for a regional high-flow frequency study. Examination of the regression constants shows that the drainage-area exponent, 5, closely approximates unity for all but the smaller duration 

periods, and the small range of variation of this exponent about the 

value of unity suggests that the variations may be random.

The regression equations in table 13 may be used to construct frequency curves for various duration periods of high flow at ungaged 

sites in the study area. The procedure that would be followed in this 

construction is similar to that for constructing flood-frequency curves 

for ungaged sites. The user of the equations is reminded that the 

equations were developed from records for watersheds whose drainage areas range from 17 to 1,342 square miles and whose mean annual 

basinwide precipitation ranges from 31 to 92 inches. The equations 

therefore should be used with caution if it is necessary to apply them 

to a watershed whose drainage area or mean annual precipitation lies 

outside these ranges of values.

The information furnished by magnitude-duration-frequency curves 

is useful in studying the hydrologic and economic aspects of reservoir 

design for flood control. Data picked from the curves can be used to 

construct a frequency-mass curve that represents the total flood volume 

produced, for a specified recurrence interval, within duration periods 

of various lengths. The traditional mass-curve method of analyzing 

the storage required to limit reservoir outflow rates to some given 

value would then be applied. This method of analysis is similar to 

the method explained and illustrated in the closing part of the lowflow analysis section of this report.
34 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

SELECTED REFERENCES

Bailey, E. HM Irwin, W. P., and Jones, D. L., 1964, Franciscan and related rocks,

and their significance in the geology of western California: California Dept.

Conserv., Div. Mines and Geology Bull. 183, 177 p. 

Benson, M. A., 1962, Factors influencing the occurrence of floods in a humid region

of diverse terrain: U.S. Geol. Survey Water-Supply Paper 1580-B, 64 p. 

California Department of Water Resources, 1965, Water resources and future

water requirements, north coastal hydrographic area, southern portion

(preliminary edition) : Bull. 142-1, 450 p. 

California Water Resources, Board, 1955, Water utilization and requirements

of California: Bull. 2,227 p. 

Oardwell, G. T., 1958, Geology and ground water in the Santa Rosa and Petaluma

Valley areas, Sonoma County, California: U.S. Geol. Survey Water-Supply

Paper 1427,273 p.

 1965, Geology and ground water in Russian River Valley areas and in 

Round, Laytonville, and Little Lake Valleys, Sonoma and Mendocino Counties, California: U.S. Geol. Survey Water-Supply Paper 1548, 154 p.

Gruff, R. W., and Rantz, S. E., 1965, A comparison of methods used in floodfrequency studies for coastal basins in California: U.S. Geol. Survey WaterSupply Paper 1580-E, 56 p.

Fenneman, N. M., 1931, Physiography of western United States: New York, 

McCraw-Hill Book Co., 534 p.

Kohler, M. A., Nordenson, T. J., and Baker, D. R., 1959, Evaporation maps for the 

United States: U.S. Weather Bureau Tech. Paper 37, 13 p.

Kunkel, Fred, and Upson, J. E., 1960, Geology and ground water in Napa and 

Sonoma Valleys, Napa and Sonoma Counties, California: U.S. Geol. Survey 

Water-Supply Paper 1495,252 p.

Lane, E. W., and Lei, Kai, 1950, Stream flow variability: Am. Soc. Civil Engineers 

Trans., v. 115, p. 1084-1134.

Linsley, R. K., and Franzini, J. B., 1964, Water-resources engineering: New York, 

McGraw-Hill Book Co., 654 p.

Rantz, S. E., 1964, Surface-water hydrology of coastal basins of northern California : U.S. Geol. Survey Water-Supply Paper 1758, 77 p.

U.S. Geological Survey, 1960, Compilation of records of surface waters of the 

United States through September 1950, Part 11-A, Pacific slope basins in 

California except Central Valley: U.S. Geol. Survey Water-Supply Paper 

1315-B, 413 p.

 1964, Compilation of records of surface waters of the United States, October 1950 to September 1960, Part 11, Pacific slope basins in California: U.S. 

Geol. Survey Water-Supply Paper 1735, 715 p.
TABLES
36 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, OALIF. 

TABLE 1. Mean monthly distribution of precipitation at selected stations

Station

Kentfleld (No. 

16). 

Healdsburg (No. 

26). .........

Fort Bragg (No. 

42).............

Upper Mattole 

(No. 43)-. 

Mean 

annual 

precipitation 

1931-63 

(in.)

46.4 

39.6 

37.9 

79.7

Mean monthly distribution of precipitation, as percentage of mean annual 

precipitation

Oct.

5.3 

5.4 

6.9 

7.3

Nov.

10 

10 

11 

12

Dec.

20 

20 

19 

19

Jan.

22 

21 

20 

20

Feb.

18 

19 

16 

16

Mar.

13 

12 

13 

13

Apr.

6.9 

7.0 

7.1 

6.0

May

3.2 

3.2 

3.9 

4.0

June

0.7 

1.2 

1.7 

1.3

July

0 

0 

.1 

.2

Aug.

0.1 

.3 

.3

.2

Sept.

0.8 

.9 

1.0 

1.0

TABLE 2. Mean annual precipitation for period 1931-63 at stations in north coastal

California

No. 

(pl. 1)

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

43

Station

Angwin Pacific Union College. ..

Saint Helena 4 WSW ... ._

Oakville 1 WNW_ ...........

Oakville 4 SW... .... 

Napa __ _ _ __ .. .. .....

Napa State Hospital _ . 

Petaluma Fire Station 2 __ .....

Novato 8 NW_- .................

Hamilton Air Force Base ........

San Rafael ____________

Kentfleld ___ .. ___ ... ......

Muir Woods ___ ____ ______

Sebastopol 4 SSE. __ - _ ....

Graton 1 W... ... ....... .........

Occidental ______ ____ .

Fort Ross ___ ___ .- .....

Cazadero. _________ .... 

Venado.- - _ _________

Healdsburg _ .. .. ______ .

Healdsburg 2 E ..................

Kellogg ____ .. . . . .._...

Skaggs Springs Los Lomas 

Ranch _________ ........

Cloverdalell W-_.- _ .. ... ..

CloverdaleS SSE--...-- __ - ...

The Geysers __ ._ __ ....

Point Arena USCG.. ..........

YorkvUle __ _.__.._____

Hopland Largo Station. .........

Ukiah.. _. ....

Ukiah 4 SW.... .............

Redwood Valley _ _ .. ..

Potter Valley Powerhouse.. ....

Fort Bragg Airway. .__ .......

Fort Bragg- ... .. .. _ .. --

Upper Mattole ______ ......

Latitude

(N)

38°34' 

38°35'

38°30'

38°30'

38°27'

38°23'

38°18'

38°17'

38°12'

38°17'

38°15'

38°14'

38°08'

38°04'

37°58'

37°57'

37°64'

38°21'

38°27'

38°26'

38°25'

38°30'

38°31'

38°32'

38°37'

38°37'

38°37'

38°38'

38°41'

38°46'

38°46'

38°48'

38°55'

38°55'

39°01'

39°09'

39°16'

39°22'

39°24'

39°27'

40°15'

Longitude 

(W)

122°26' 

122°35'

122°28'

122°32'

122°25'

122°28'

122°17'

122°16'

122°18'

122°27'

122°38'

122°38'

122°43'

122°31'

122°32'

122°33'

122°34'

122°49'

122°42'

122°53'

122°59'

123°00'

123°15'

123°08'

123°01'

122°52'

122°52'

122°39'

123°08'

123°13'

122°59'

122°49'

123°42'

123°43'

123°16'

123°07'

123°12'

123°16'

123°12'

123°08'

123°49'

123°48'

124°11'

Altitude 

(ft)

1,815 

365

255

1,792

160

1,465

16

60

20

20

30

16

350

3

31

45

171

145

167

210

1,000

115

116

1,040

1,260

102

102

1,360

1,930

1,820

320

1,600

197

235

1,100

550

623

1, 550

718

1,014

61

80

255

Period of 

record

1939-63 

1931-63

1907-63

1940-63

1953-62

1943-62

1945-63

1877-1963

1955-63

1952-63

1943-63

1871-1963

1943-63

1934-33

1947-63

1888-1963

1940-63

1942-63

1888-1963

1896-1963

1940-63

1939-63

1875-1963

1939-63

1939-63

1877-1963

1952-63

1943-63

1939-63

1940-63

1887-1963

1939-63

1940-63

1938-57

1941-54

1943-63

1877-1963

1940-63

1939-63

1909-63

1940-63

1896-1963

1886-1963

Estimated 

33-year mean 

annual 

precipitation 

(in.)

37.8 

36.1

33.1

39.8

31.2

37.3

23.2

23.8

20.0

27.2

22.7

23.9

30.6

25.2

36.6

46.4

35.7

30.6

28.9

40.6

50.9

45.8

39.0

71.1

56.1

39.6

36.3

42.7

57.4

59.6

39.3

53.9

39.3

32.9

46.0

34.9

35.6

49.5

34.6

43.9

38.5

37.9

79.7
TABLES 37

TABLE 3. Hydrologic budget for watersheds upstream from key stream-gaging 

stations, for base period 1931-63

Gaging station

No.

(pl. 1)

4560 

4565 

4570 

4580

4585

4590 

4595 

4600

4605

4608

4610 

4615

4625 

4627 

4629 

4630 

4632

4637 

4639 

4639.4 

4640 

4645 

4648.8

4652 

4653 

4658

4670 

4670. 5 

4672

4675 

4675. 5

4676

Name

Napa River basin

Conn Creek near St. Helena-. __

Sonoma Creek basin 

Sonoma Creek at Boyes Hot

Petaluma River basin 

Petaluma River at Petaluma 

Novato Creek basin

Corte Madera Creek basin

Lagunitas Creek basin

Lagunitas Creek above Nicasio 

Creek 2. __.___ ______.._.. 

Nicasio Creek near Point Reyes

Walker Creek basin

Russian River basin

East Fork Russian River near

Russian River near Hopland. . 

Cummisky Creek near Cloverdale. 

Russian River near Cloverdale ... 

Big Sulphur Creek near

Sausal Creek near Healdsburg. ...

Russian River near HealdsburgWarm Springs Creek at Skaggs

Santa Rosa Creek near Santa

Russian River near Guefneville 

Big Austin Creek at Cazadero... .. 

Austin Creek near Cazadero- -- _

Gualala River basin 

South Fork Gualala River near

North Fork Gualala River near

Garcia River basin 

Garcia River near Point Arena_ _

Drainage 

area 

(sq mi)

81.4 

53.2 

17.4

218

62.2 

30.9 

17.5 

18.1

42.5 

36.2

37.1

99.7

93.0 

362 

31.1 

13.4

502

82.3 

11.2 

43.4

15.7 

793

87.8

32.7 

162 

11.8

12.5 

1,340 

26.5 

63.1

161 

39.2

98.5

Average annual basinwide values

Consumptive use 

of applied 

water 

(acre-ft)

1,200 

(0 (') 

5,000

500 

500 

(0 

(')

(') 

C)

W

250

4,500 

8,000 

(') 

100 

10,000

(') (!)

1,300 

400 

18,000 

(>)

0) 

200 

0)

100 

31,000

0) 0)

0)

O

0)

Precipitation 

(in.)

43 

37 

44 

41

45 

31 

30 

40

48 

38

40

46

40 

45 

47 

44 

44

52 

47 

56 

42 

45 

50

54 

50 

50

48 

45 

70 

65

58 

67

64

Natural runoff

Thousands of 

acre-feet

63.1 

23.9 

13.0 

135.0

43.8 

11.5

8.4 

17.2

44.0 

27.0

31.1

121.0

77.5 

332.0 

30.4 

13.2 

476.0

126.0 

13.7 

58.7 

13.4 

808.0 

110.0

49.9 

198.0 

14.8

12.9 

1, 367. 0 

68.2 

135.0

272.0 

100.0

238.0

Inches

14.5 

8.4 

14.0 

11.6

13.2

7.0 

9.0 

17.8

19.4 

14.0

15.7

22.8

15.6 

17.2 

18.3 

18.5 

17.8

28.7 

22.9 

25.4 

16.0 

19.1 

23.5

28.6 

22.9 

23.5

19.4 

19.1 

48.3 

40.1

31.7 

47.8

45.3

Water 

loss 

(in.)

28 

29 

30 

29

32 

24

21 

22

29 

24

24

23

24

28 

29 

26 

26

23 

24 

31 

26 

26 

26

25 

27 

26

29

26 

22 

25

26 

19

19

See footnotes at end of table.
38 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

TABLE 3. Hydrologic budget for watersheds upstream from key stream-gaging 

stations, for base period 1931-68 Continued

Gaging station

No. 

(pl. 1)

4676. 5 

4677 

4677. 5

4678 

4680

4680.7 

4681

4685

4686 

4686.5 

4687

4690 

4695

4695. 5

Name

Alder Creek basin 

Alder Creek near Manchester __ 

Elk Creek basin 

Elk Creek near Elk. __ . .........

Greenwood Creek basin

Navarro River basin 

Rancheria Creek near Boonville _

Big River basin 

South Fork Big River near

Big River near Mendocino.. __ _

Noyo River basin

Ten Mile Riser basin

Middle Fork Ten Mile River near 

FortBragg.. .... __ ___ .

North Fork Ten Mile River near

South Fork Ten Mile River near

Mattole River basin

Mattole River near Petrolia . ..... 

North Fork Mattole River at

Bear River basin

Drainage 

area 

(set mi)

26.6 

24.8 

24.2

65.6 

303

36.2 

152

106

33.3 

39.1 

26.5

240 

37.6

78.3

Average annual basinwide values

Consumptive use 

of applied 

water 

(acre-ft)

0) 

(') 

0)

100 

500

0) (')

0)

(') 

(') 

(')

0) 

(')

0)

Precipitation 

(in.)

60 

58 

54

52 

53

50 

52

56

58 

58 

54

92

82

75

Natural runoff

Thousands of 

acre-feet

58.6 

51.0 

34.8

96.5 

322.0

35.2 

138.0

138.0

60.0 

68.0 

34.2

874.0 

122.0

237.0

Inches

41.3 

38.6 

27.0

27.6 

19.9

18.2 

17.0

24.4

33.8 

32.6 

24.2

68.3 

60.8

56.8

Water 

loss 

(in.)

19 

19

27

24 

33

32 

35

32

24 

25 

30

24 

21

18

1 Negligible

2 No gaging stations in basin; estimate of runoff furnished by Marin Municipal Water District.
TABLES 39

TABLE 4.-2?af chart of records for stream-gaging stations in north coastal California,

Legend: Complete-record station Partial-record station C

Period of record

, | rH r-| rH

Gaging station

Drainage

area 

(sq mi)

Station 

No.

Napa River basin: 

nrtl I Sulphur Creek near St. Helena............ 4.49 4559.5

Napa River near St. Helena-- --- .. 81.4 4560 

Conn Creek near St. Helena..____ . 53.2 4565 

Dry Creek hear Napa________.-.-_. .17.4 4570 

Dry Creek near Yountville__ ______. 18.8 4575 

Napa River near Napa.--........^.......... 218 4580

Redwood Creek near Napa. ....- . 9.81 4582

Sonoma Creek basin: 

HI_ Sonoma Creek near Kenwood.-.--_. .... 6.06 4584

Sonoma Creek at Boyes Hot Springs...._. 62.2 4585

Petaluma River basin:

Petaluma River at Petaluma__ _*____. 30.9 4590

Novato Creek basin:

Novato Creek near Novato.. ___ __ __. 17.5 4595

Corte Madera Creek basin:

CorteMadera Creek at Ross......_....... 18.1 4600

Lagunitas Creek basin: 

Lagunitas Creek:

Nicasio Creek near Point Reyes Station_. 36.2 4605 

Walker Creek basin: 

Walker Creek:

Arroyo Sausal near Marshall___-__. 19.2 4607 

Walker Creek near Tomales........... .... 37.1 4608

Salmon Creek basin:

Salmon Creek at Bodega________.__. 15.7 4609.2

Russian River basin:

Russian River near Ukiah..._...... ... 99.7 4610

Potter Valley powerhouse tailrace near

Potter Valley.. _- ___----- ...... 4710

East Fork Russian River tributary near 

Potter Valley.. .-... ... .15 4614

East Fork Russian River near Calpella . 93.0 4615 

East Fork Russian River near Ukiah . 105 4620 

Robinson Creek near Ukiah..-,. ----- 19.9 4621

Russian River near Hopland.------ 362 4625

Feliz Creek near Hopland 31.1 4627

JL ]_ Cummisky Creek near Cloverdale.. 13.4 4629 

Russian River near Cloverdale . 502 4630 

Big Sulphur Creek near Cloverdale____- 82.3 4632 

Russian River, at Geyserville .___- .... 656 4635

Sausal Creek near Healdsburg.. . 11.2 4637 

Maacama Creek near Kellogg:. - ... 43.4 4639 

nrtl I Franz Creek near Kellogg. .. 15.7 4639.4 

Russian River near Healdsburg.....-------.-. 793 4640

Dry Creek near Cloverdale---...---------. 87.8 4645

Warm Springs Creek at Skaggs Springs.. 32.7 4648.8 

Dry Creek near Healdsburg_____.._.. 131 4650 

Dry Creek near Geyserville--.... . 162 4652

Mill Creek near Healdsburg--. .. 11.8 4653 

Mark West Creek at Mark West Springs 30.5 4654.5 

I I I I Mark West Creek near Windsor _. ____. 42.8 4655 

Laguna de Santa Rosa:

Santa Rosa Creek near Santa Rosa .. 12.5 4658 

Santa Rosa Creek at Santa Rosa__. 56.4 4662 

Russian River near Guerneville....._........ 1,340 4670

IQ_1 Big Austin Creek at Cazadero.. __.... .26.5 4670.5

Austin Creek near Cazadero .. 63.1 4672
40 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

TABLE 4,-Bar chart of records for stream-gaging stations in north coastal

California Continued

Legend: Complete-record station Partial-record station i HU

Period of record

3 N * * § S ? Gaging station

__

__

__

m 

 i

 i

 i

 i

 i

i

 

 i

 i 

i

 i

 i

 i

 _

i

 _

t_

i_

Gualala River basin: 

South Fork Gualala River near Annapolis 

North Fork Gualala River near Gualala . 

Garcia River basin: 

Garcia River near Point Arena.. .. 

Alder Creek basin:

Elk Creek basin: 

Elk Creek near Elk ______ ____ ...

Greenwood Creek basin:

Navarro River basin: 

Navarro River:

Albion River basin:

JBig River basin: 

Big River: 

South Fork Big River near Comptche ..

Noyo River basin.

Ten Mile River basin: 

Middle Fork Ten Mile River near Fort Bragg.. 

North Fork Ten Mile River near Fort Bragg-.. 

South Fork Ten Mile River near Fort Bragg. . 

Cottoneva Creek basin: 

Cottoneva Creek:

Mattole River basin"

Bear River basin: 

Bear River at Capetown.... . 

Drainage 

area 

(sq mi)

161 

39.2

98.5 

26.6 

248 

24.2

65.6 

303

144

36.2 

152

106

33.3 

39.1 

26.5

1,88

240 

37.6

78.3

Station 

No.

4675 

4675.5

4676 

4676.5 

4677 

4677.5

4678 

4680

4680.1

4680.7 

468.1

4685

4686 

4686.5 

4687

4688..S

4690 

4695

4695.5
TABLE 5. Flow-duration summary of daily discharge for selected 

Time (percent)

99.9-_ 

99 

98. 

95 

90 , .. .. __ __ _

80 _ 

70

60-- -

50 . . _ 

4.n

30- 

20

10 . . ...

5 .. . __ 

2 _ _. . _ ..... . ___ .. ._ 

1. . . 

0.5. . 

0.1---- 

Napa River basin

Napa River near St. 

Helena (4560)

1929-32, 1939-63

81.4 sq mi

Conn Creek near St. 

Helena (4565)

1929-59

53.2 sq mi

Dry Creek n

(4570

1951-

17.4 sq 

Dischage that is equaled or exceeded during perce

cfs

0 

0 

.05 

.08

.15 

.30 

.75 

1.5

2.9 

6.2 

13 

25

55 

158 

380 

900

1,450 

2,030 

4,200

cfs per 

sq mi

0 

0 

.0006 

.0010

.0018 

.0037 

.0092 

.0184

,035ft 

.0762 

.160 

.307

.676 

1.94 

4.67 

11.1

17.8 

24.9 

51.6

cfs

0 

0 

0 

0

0 

0 

0 

.02

.30 

2.1 

4.7 

9.3

21 

64 

162 

405

660 

950 

2,000

cfs per 

sqmi

0 

0 

0 

0

0 

0 

0 

.0004

.0056 

.0395 

.0883 

.175

.395 

1.20 

3.05 

7.61

12.4 

17.9 

37.6

cfs

0 

0 

0 

0

0 

0 

.06 

.21

.54 

1.3 

2.7 

5.2

11 

32

77 

182

300 

420 

850
TABLE 5. Flow-duration summary of daily discharge for selected stream

Gaging station _ .. ______ . _________

Time (percent)

99.9 

99.5 __ - - _ . .. 

99 ...... .- ... .. _ .. _ _ . ...

98 ... ____ -- __ ......... _____ --. ....

95 .. . _ __ .. _ _ . . _

90 - __ . __ __ . - - __ _ ..

80-. 

70 -

60

50 ... ...

40 

30 ....

20 

10.. 

5 ... .

2 ___ . ..... ___ _______ 

1 . . _ . _. __ _ .

0.5 .... _ ... .. - __ . 

0.1 

Novato Creek near 

Novato 

(4595)

1946-63

17.5 sqmi

Corte Madera Creek 

at Ross 

(4600)

1951-63

18.1 sq mi

Nicasio Cre

Point Reyes 

(4605)

1953-6

36.2 sq 

Discharge that is equaled or exceeded during percent 

cfs

0 

0 

0 

0

0 

0 

0

0

.02 

.14 

.62 

1.9

5.5 

18 

50 

135

230 

350 

810

cfs per 

sq mi

0 

0 

0 

0

0 

0 

0 

0

.0011 

.0080 

.0354 

.109

.314 

1.03 

2.86 

7.71

13.1 

20.0 

46.3

cfs

0

0 

0 

.05

.10 

.18 

.36 

.60

1.0

1.9 

3.3

5.5

11

36 

94 

235

390 

540 

1,200

Cfs per 

sq mi

0

0 

0 

.0028

.0055 

.0099 

.0199 

.0331

.0552 

.105 

.182 

.304

.608 

1.99 

5.19 

13.0

21.5 

29.8 

66.3

cfs

0 

0 

0 

0

0

0 

.06 

.10

.18 

.66 

2.8 

6.0

16 

56 

155 

400

650 

970 

1,900
TABLE 5. Flow-duration summary of daily discharge for selected stream

Drainage area . _ _ _ _ _ _

Time (percent)

99.9. 

99.5

99.. _ 

98 

95-.- 

90 

80

70

60

50 

40 

in

20 

10 

5.. 

2 _ .... _

1 .. . . . .....

0.5 __ _ . . .. ....

0.1-. 

Eussian Eiver bas

Russian River near 

Hopland (4625)

1939-63

362 sq mi

Feliz Creek near 

Hopland (4627)

1958-63

31.1 sq mi

Russian Ri

Cloverdal

1951-

502 sq 

Discharge that is equaled or exceeded daring percen

cfs

0 

0 

0 

0.05

0.1 

.2 

.5 

1.7

5.5 

23 

88 

203

470 

1,050 

2,000 

3,750

5,400 

7,400 

13, 300

cfs per 

sq mi

0 

0 

0 

.0001

.0003 

.0006 

.0014 

.0047

.0152 

.0635 

.243 

.561

1.30 

2.90 

5.52 

10.4

14.9 

20.4 

36.7

cfs

0 

0 

0 

0

0 

0 

0 

.06

1.1 

3.2

7.2 

14

36 

86 

170 

415

640 

870 

1,350

cfs per 

sqmi

0

0 

0 

0

0 

0 

0 

.0019

.0354 

.103 

.232 

.450

1.16

2.77 

5.47 

13.3

20.6 

28.0 

43.4

cfs

0

0 

0 

.08

.15 

.3 

.8 

3.0

10 

40 

135

275

650 

1,510 

2,950 

5,850

8,600 

12, 100 

22,200
TABLE 5. Flow-duration summary of daily discharge for selected stream

Drainage area. ____________________

Time (percent)

99.9

99.5 ___ . __ __ .. __ .. __ .

m........... .....................................

98

95.--..... .......... _ ............ __ ........

90.. 

80 _ ._

70 . 

60.. .... ......... .................

50-. ... ..... ... . .- .- ... ...

40.. 

30.... ....... ........ . ..... ........

20 .

10.... ...-.... ...................... .......

5 ___ _ ....

2...-..... . ...................................

1 _______ . ________ __ .....

0.5. _ ........................

O.I......... ...... .. . .

Russian River basin Continued

Dry Creek near 

Cloverdale (4645)

1941-63

87.8 sq mi

Russian River near 

Guerneville (4670)

1939-63

1,340 sq mi

South Fork 

River near A

(4675

1950-6

161 sq 

Discharge that is equaled or exceeded during percent 

cfs

0.03 

.05 

.06 

.09

.16 

.37 

1.3 

3.1

6.8 

15 

34 

66

145 

320 

660 

1,280

1,880 

2,620 

4,600

cfs per 

sqmi

0.0003 

.0006 

.0007 

.0010

.0018 

.0042 

.0148 

.0353

.0774 

.171 

.387

.752

1.65 

3.64 

7.52 

14.6

21.4 

29.8 

52.4

cfs

6.0 

8.0 

9.5 

11

15 

19 

26 

38

55 

110 

310 

720

1,700 

4,000 

8,000 

15, 000

21,000 

29,000 

48,000

cfs per 

sq mi

0. 0045 

.0060 

.0071 

.0082

.0112 

.0142 

.0194 

.0284

.0410 

.0821 

.231 

.537

1.27 

2 99 

5.' 97 

11.2

15.7 

21.6 

35.8

cfs

0.3 

.6 

.8 

1.2

2.1 

3.4

6.7 

12

23 

40 

76 

140

320 

810 

1,600 

3,200

5,000 

7,100 

12,600

See footnote at end of table.
TABLE 5. Flow-duration summary of daily discharge for selected stream

Gaging station

Time (percent)

99.9 __________ - ___ - - - __ .

99.5

99__________ ............ ...........................

98 . __ . . ... __ . .. ....

95

90 - _ . ....

80 ----- . .. ___ ... _- _ -- --

70 

60 

50

40

30 - __ ------- ...

20 . -

10 

5. .. _ . .... ___ - ...... .

2

1

0.5 _. . .

0.1

Alder Creek near 

Manchester i (4676.5)

1951-56

26.6 sq mi

Elk Creek near Elk 1 

(4677)

1951-56

24.8 sq mi

Greenwood 

Elk i (4

1951-

24.2 sq 

Discharge that is equaled or exceeded daring percen

cfs

0.9 

1.2 

1.4 

1.6

2.1 

2.7 

3.7

4.7

6.8 

10 

17 

31

69 

172

cfs per 

sqmi

0.0338 

.0451 

.0526 

.0602

.0789 

.102 

.139 

.177

.256 

.376 

.639 

1.17

2.59 

6.47

cfs

0.9 

1.2 

1.4 

1.6

2.1 

2.7 

3.8 

5.1

7.4 

11 

18 

32

64 

155

cfs per 

sqmi

0.0363

.0484 

.0565 

.0645

.0847 

.109 

.153 

.206

.298 

.444 

.726 

1.29

2.58 

6.25

cfs

0 

0 

.10 

.15

.3 

.6 

1.3 

2.3

3.9 

6.4 

11 

21

44 

107

See footnote at end of table.
TABLE 5. Flow-duration summary of daily discharge for selected ste

Time (percent)

99.9 

99.5 

99 

98 

95

90 

80 

70-. 

60 ___ ____ - -

50 

30-.- 

20 

10

5

2

1.- 

0,5 

0.1 

Big River near Mendocino i (4681)

1951-56

152 sq mi

Noyo River near Fort 

Bragg (4685)

1951-63

106 sq mi

Middle Fork 

River near Fo

(4686

1951-5

33.3 sq 

Discharge that is equaled or exceeded during percent 

cfs

0.6 

1.0 

1.3 

1.7

2.7 

4.2 

7.5 

12

21 

33 

56 

95

190 

440

cfs per sq mi

0.0039 

.0066 

.0086 

.0112

.0178 

.0276 

.0493 

.0789

.138 

.217 

.368 

.625

1.25 

2.89

cfs

0.6 

1.0 

1.3 

1.7

2.7 

4.2 

7.5 

12

21 

33

56 

95

190 

440 

810 

1,500

2,200 

3,000 

5,400

cfs per sq mi

0.0057 

.0094 

.0123 

.0160

.0255 

.0396 

.0708 

.113

.198 

.311 

.528 

.896

1.79 

4.15 

7.64 

14.2

20.8 

28.3 

50.9

cfs

0.3

.5 

.7 

1.0

1.7 

2.7 

4.7 

7.0

11 

16 

26 

42

83 

190

cfs 

See footnote at end of table.
TABLE 5. Flow-duration summary of daily discharge for selected steam

Time (percent)

99.9 ..

99.5 .____._. _._-_. _._..-..__ __._._.

99........... _ . ____ ............ _ ..........

98. _ ............. _ ....... ____ ______.___._--

95........... _ ... __ ..... _ . _ . .. .........

90................................................

80-........................................ .......

70 _-_._._._.__..._.._._..._-_....._.__.___.-...

60............................... _____ ___

50 . _.____ _...__.______. __ _.__

40 _- .-._._. _ _-_--_-.___________. -

30 . _ .. . _.__ _. .

20-................................. ..........

10,.- __ _ _.______ ___ .

5...... __ .. _ . __ . _ . __ .............. _ ..

2 _ ......... ___ ............. _ __ .... _ ..

1...... _ . _ . ....... _ ..... . __ _

0.5........ _ ..... _ ..... ____ ... _ ..........

0.1......... _ . ____ ............ __ ...... ...

Mattole River basin

Mattole River near 

Petrolia (4690)

1950-63

240 sq mi

North Fork 

River at Petro

1951-5

37.6 sq 

Discharge that is equaled or exceeded 

adjusted to base p

cfs

4.5 

7.2 

9.0 

12

18 

28 

49 

81

138 

240 

420 

710

1,420 

2,950 

4,950 

8,600

12,100 

16,000 

25,000

cfs per 

sq mi

0.0188 

.0300 

.0375 

.0500

.0750 

.117 

.204 

.338

.575 

1.00 

1.75 

2.96

5.92 

12.3 

20.6 

35.8

50.4 

66.7 

104

cfs

0.7 

1.1 

1.4 

1.8

2.8 

4.2 

7.4 

12

20 

34 

59 

99

200 

413 

693 

1,200

1,700 

2,240 

3,500

i Partial-record station.
48 SURFACE WATE.R, SAN FRANCISCO BAY TO EEL RIVER, CALIF. 

TABLE 6. Mean monthly distribution of runoff at selected gaging stations

Gaging station

Napa River near 

St. Helena 

(sta. 4560)...... 

Navarro River 

near Navarro 

(sta. 4680)......

Mattole River 

near Petrolia 

(sta. 4690) ......

Mean 

annual 

runoff 

1931-63 

(thousands 

of acreft)

63.1

322 

874

Mean monthly distribution of runoff, as percentage of mean annual runoff

Oct.

0.3

1.2 

2.5

Nov.

1.7

2.4 

6.4

Dec.

20.2 

17.4 

17.8

Jan.

27.5 

28.7 

27.1

Feb.

27.1 

25.6 

20.9

Mar.

12.6 

13.3 

11.3

Apr.

7.6 

7.1 

7.0

May

2.1

2.6 

4.5

June

0.6 

.9 

1.4

July

0.2 

.4 

.5

Aug.

0.06 

.2 

.3

Sept.

0.04 

.2 

.3

TABLE 7. Low-flow frequency table for selected stream-gaging stations 

[Discharge adjusted to base period Apr. 1,1931-Mar. 31,1963]

Station 

No.

4560

4565

4570

4585

4590

Gaging station

Napa River

near St.

Helena.

Conn Creek

near St.

Helena.

Dry Creek

near Napa.

Sonoma Creek

at Boyes Hot

Springs.

Petaluma

River at

Petaluma.

Number of 

consecutive 

days

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

Ordinates of low-flow frequency curves, in cubic feet per second, for 

indicated recurrence intervals, in years

1.02

1.1

1.2

1.3

1.5

1.7

2.2

3.2

9.5

120

0

0

0

0

.25

.45

.75

3.3

50

0

0

0

0

0

.45

.65

2.0

24

0.85

.90

1.0

1.1

1.3

1.6

2.3

6.6

84

0

0

0

0

0

.01

.03

.35

28

1.10

0.80

.90

1.0

1.1

1.3

1.6

2.2

6.4

86

0

0

0

0

.10

.22

.45

2.1

34

0

0

0

0

0

.32

.45

1.3

17

0.60

.70

.80

.85

1.0

1.2

1.6

4.5

60

0

0

0

0

0

0

.01

.15

16

1.3

0.45

.55

.65

.80

1.0

1.2

1.6

4.5

53

0

0

0

0

.03

.07

.22

1.3

20

0

0

0

0

0

.24

.32

.90

11

0.30

.40

.48

.60

.80

.90

1.2

3.2

37

0

0

0

0

0

0

0

.07

7.0

2.0

0.15

.22

.30

.40

.55

.70

.90

2.5

19

0

0

0

0

0

0

.01

.55

7.0

0

0

0

0

0

.12

.17

.50

4.0

0.03

.09

.16

.26

.40

.50

.70

1.8

13

0

0

0

0

0

0

0

.01

1.3

5.0

0.02

.03

.06

.11

.23

.33

.40

1.0

6.3

0

0

0

0

0

0

0

.03

2.1

0

0

0

0

0

.02

.04

.20

1.3

0

0

0

.01

.10

.20

.26

.80

4.4

0

0

0

0

0

0

0

0

.15

10

0

.01

.02

.05

.12

.19

.24

.55

3.8

0

0

0

0

0

0

0

0

1.0

0

0

0

0

0

0

0

.08

.80

0

0

0

0

.02

.06

.10

.40

2.7

0

0

0

0

0

0

0

0

.05

20

0

0

0

.02

.07

.11

.14

.32

2.5

0

0

0

0

0

0

0

0

.55

0

0

0

0

0

0

0

.02

.50

0

0

0

0

0

.01

.03

.18

1.8

0

0

0

0

0

0

0

0

.01

30

0

0

0

.01

.05

.08

.11

.23

2.1

0

0

0

0

0

0

0

0

.40

0

0

0

0

0

0

0

0

.42

0

0

0

0

0

0

.01

.10

1.6

0

0

0

0

0

0

0

0

0

50

0

0

0

0

.03

.05

.07

.15

1.8

A

0

0

0

0

0

0

0

.30

0

0

0

0

0

0

0

0

.36

0

0

0

0

0

0

0

.03

1.4

0

0

0

0

0

0

0

0

0
TABLES 49

TABLE 7. Low-flow frequency table for selected stream-gaging stations Continued

Station 

No.

4595

4600

4605

4610

4615

4625

4627

Gaging station

Novato Creek

near Novato.

Corte Madera

Creek at

Ross.

Nicasio Creek

near Point

Reyes Station.

Russian River

nearUkiah.

East Fork

Russian

River near

Calpella.

Russian River

near Hopland.

Feliz Creek

near Hopland.

Number of 

consecutive 

days

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

Ordinates of low-flow frequency curves, in cubic feet per second, for 

indicated recurrence intervals, in years

1.02

0

0

.01

.02

.03

.05

.10

.56

20

0.55

.58

.62

.65

.75

.87

1.1

2.6

31

0.09

.09

.10

.11

.12

.14

.22

1.6

55

0.78

.84

.92

1.1

2.0

3.0

4.7

26

180

0.10

.11

.13

.17

.40

.67

1.1

10

110

0.85

.90

1.0

1.2

2.2

3.4

5.5

58

530

.08

.10

.12

.16

.40

.70

1.2

7.6

52

1.10

0

0

0

0

.01

.02

.05

.33

12

0.45

.50

.53

.55

.62

.70

.87

1.9

22

0.07

.08

.09

.10

.11

.12

.15

.80

35

0.31

.36

.43

.50

.78

1.2

2.0

12

117

0.02

.03

.04

.05

.10

.19

.38

4.0

68

0.38

.42

.50

.58

.85

1.3

2.2

17

350

0

0

.01

.02

.08

.19

.40

3.3

34

1.3

0

0

0

0

0

0

.02

.18

6.4

0.30

.35

.38

.45

.53

.58

.70

1.4

13

0.05

.06

.07

.08

.09

.10

.11

.36

18

0.14

.16

.20

.23

.31

.54

1.0

6.2

75

0

.01

.01

.02

.03

.05

.14

1.8

41

0.21

.24

.28

.31

.38

.60

1.0

7.5

230

0

0

0

0

0

.03

.14

1.6

22

2.0

0

0

0

0

0

0

0

.06

1.5

0.10

.15

.20

.27

.35

.40

.50

.95

4.7

0.01

.02

.03

.04

.06

.07

.08

.16

4.5

0.05

.06

.07

.09

.12

.20

.44

2.8

38

0

0

0

0

0

.01

.04

.56

18

0.11

.12

.14

.16

.19

.28

.50

3.0

105

0

0

0

0

0

0

.01

.64

11

5.0

0

0

0

0

0

0

0

0

.30

0

0

.04

.07

.16

.23

.27

.53

1.8

0

0

0

0

.02

.03

.04

.09

.75

0.01

.02

.02

.03

.04

.06

.14

1.0

14

0

0

0

0

0

0

.01

.13

4.5

0.05

.06

.07

.08

.10

.14

.21

1.0

22

0

0

0

0

0

0

0

.14

4.0

10

0

0

0

0

0

0

0

0

.13

0

0

0

.02

.08

.13

.17

.35

1.3

0

0

0

0

0

.01

.02

.06

.28

0

0

.01

.01

.02

.03

.06

.61

7.4

0

0

0

0

0

0

0

.07

2.0

0.03

.04

.04

.05

.07

.09

.13

.69

9.5

0

0

0

0

0

0

0

.04

2.0

20

0

0

0

0

0

0

0

0

.06

0

0

0

0

.03

.07

.10

.22

.97

0

0

0

0

0

0

.01

.04

.16

0

0

0

0

.01

.02

.03

.32

4.3

0

0

0

0

0

0

0

.02

1.0

0.02

.02

.03

.04

.05

.06

.08

.40

5.0

0

0

0

0

0

0

0

0

1.1

30

0

0

0

0

0

0

0

0

.04

0

0

0

0

.01

.04

.07

.16

.87

0

0

0

0

0

0

0

.02

.14

0

0

0

0

0

.01

.02

.21

3.3

0

0

0

0

0

0

0

.01

.72

0.01

.02

.02

.03

.03

.04

.06

.29

3. 7

0

0

0

0

0

0

0

0

.78

50

0

0

0

0

0

0

0

0

.03

0

0

0

0

0

.01

.04

.10

.79

0

0

0

0

0

0

0

.01

.13

0

0

0

0

0

0

.01 .11

2.4

0

0

0

0

0

0

0

0

.49

0

.01

.01

.02

.02

.03

.04

.18

2.6

0

0

0

0

0

0

0

0

.52
50 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF. 

TABLE 7. Low-flow frequency table for selected stream-gaging stations Continued

Station 

No.

4630

4632

4640

4646

4670

4675

4675. 5

Gaging station

Russian River

near Cloverdale.

Big Sulphur

Creek near

Cloverdale.

Russian River

near Healdsburg.

Dry Creek near

Cloverdale.

Russian River

near Guemeville.

South Fork

Gualala

River near

Annapolis.

North Fork

Gualala

River near

Gualala.

Number of 

consecutive 

days

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

1S3

274

1

7

14

30

60

90

120

1S3

274

1

7

14

30

60

90

120

183

274

Ordinates of low-flow frequency curves, in cubic feet per second, for 

indicated recurrence intervals, in years

1.02

1.4

1.5

1.7

2.1

4.0

6.4

10

92

730

7.0

7.2

7.5

7.8

9.2

11

14

37

160

19

20

21

22

27

32

40

170

1,200

2.0

2.1

2.3

2.6

3.9

5.0

7.5

26

175

31

32

34

36

43

51

63

250

1,900

8.8

9.4

9.8

11

15

19

23

72

420

6.5

6.8

7.0

7.5

9.1

11

12

29

150

1.10

0.58

.65

.78

.91

1.4

2.3

4.0

30

480

5.0

5.2

5.6

6.0

6.6

7.6

9.2

22

112

14

15

16

17

19

22

27

72

810

0.92

1.0

1.2

1.4

1.9

2.8

4.0

12

115

24

25

27

29

32

36

43

110

1,230

5.5

6.0

6.6

7.2

9.0

11

15

41

275

4.9

5.1

5.4

5.7

6.5

7.5

9.1

18

100

1.3

0.32

.36

.42

.47

.59

.94

1.7

12

320

3.9

4.1

4.4

4.6

4.9

5.6

7.3

14

80

11

12

13

14

15

17

20

46

550

0.45

.52

.60

.67

.92

1.5

2.4

7.5

75

19

20

22

24

26

28

33

72

800

3.7

4.1

4.5

4.8

5.5

7.3

10

28

180

3.8

4.1

4.3

4.6

4.9

5.8

7.1

14

67

2.0

0.17

.18

.21

.24

.29

.42

.78

5.2

155

2.9

3.0

3.2

3.4

3.7

4.1

5.3

9.8

48

8.6

9.0

9.5

10

11

13

15

31

270

0.18

.21

.24

.28

.38

.60

1.2

4.8

38

15

16

17

18

19

23

25

49

390

2.2

2.5

2.7

3.0

3.4

4.5

6.5

18

97

2.9

3.1

3.3

3.5

3.7

4.3

5.4

10

38

5.0

0.08

.09

.11

.13

.15

.21

.32

1.8

38

2.0

2.1

2.2

2.4

2.7

3.0

3.8

6.7

24

6.2

6.7

7.2

7.7

8.4

9.5

11

20

85

0.08

.09

.10

.12

.16

.23

.44

2.4

14

11

12

13

14

15

17

19

33

115

1.2

1.4

1.5

1.7

2.1

2.8

3.6

9.8

46

2.1

2.3

2.4

2.6

2.8

3.3

3.8

7.0

20

10

0.05

.06

.07

.08

.11

.14

.20

1.1

17

1.6

1.7

1.8

2.0

2.2

2.5

3.0

5.7

16

4.9

5.4

5.8

6.2

7.2

8.0

9.2

18

52

0.06

.07

.08

.09

.11

.14

.22

1.7

8.4

9.5

10

11

12

13

14

16

30

81

0.78

.95

1.0

1.2

1.5

1.9

2.6

7.9

31

1.6

1.8

1.9

2.1

2.4

2.7

3.2

6.0

15

20

0.03

.04

.05

.06

.08

.09

.13

.60

9.4

1.3

1.4

1.5

1.6

1.8

2.1

2.5

4.6

11

3.8

4.2

4.7

5.3

6.0

6.8

7.6

15

38

0.04

.05

.05

.06

.07

.09

.13

.98

6.2

7.4

8.0

9.0

10

11

12

14

25

60

0.53

.61

.70

.86

1.0

1.3

1.8

5.6

24

1.3

1.4

1.5

1.7

1.9

2.2

2.6

5.0

12

30

0.02

.03

.03

.04

.06

.07

.09

.44

6.9

1.1

1.2

1.3

1.4

1.6

1.8

2.2

3.9

10

3.3

3.6

4.1

4.6

5.2

6.0

6.8

13

33

0.03

.04

.04

.05

.06

.07

.10

.64

5.4

6.6

7.1

8.0

9.0

10

11

13

22

52

0.38

.42

.53

.69

.77

.94

1.4

4.6

20

1.0

1.1

1.3

1.5

1.6

1.8

2.3

4.4

11

50

0.01

.02

.02

.03

.04

.05

.06

.27

4.8

0.90

1.0

1.1

1.2

1.3

1.4

1.8

3.1

9.0

2.8

3.1

3.4

3.8

4.2

4.9

5.6

10

29

0.02

.03

.03

.04

.04

.05

.07

.36

4.4

5.8

6.2

6.8

7.5

8.2

9.4

11

18

46

0.22

.26

.32

.43

.49

.61

1.0

3.3

16

0.73

.80

.92

1.1

1.2

1.4

1.9

3.6

9.5
TABLES 51

TABLE 7. Low-flow frequency table for selected stream-gaging stations Continued

Station 

No.

4676.5

4677

4678

4680

4681

4685

4686

Gaging station

Alder Creek

near Manchester.

Elk Creek near

Elk.

Rancheria

Creek near

Boonville.

Navarro River

near

Navarro.

Big River near

Fort Bragg.

Noyo Eiver

near Fort

Bragg.

Middle Fork

Ten Mile

River near

Fort Bragg.

Number of 

consecutive 

days

1

7

14

onoU

60

90

120

183

374

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

Ordinates of low-flow frequency curves, in cubic feet per second, for 

indicated recurrence intervals, in years

1.02

4.1

4.2

4.4

4.6 

5.4

6.1

6.9

16

90

4.3

4.5

4.7

4.9

5.9

6.8

7.7

18

80

4.1

4.4

4.7

5.2

6.7

8.6

11

27

147

17

18

19

21

26

32

38

94

450

9.2

9.6

10

11

14

17

20

48

215

9.2

9.6

10

11

14

17

20

48

215

5.5

5.7

6.0

6.5

7.9

9.3

11

23

95

1.10

3.3

3.4

3.6

O o

O. O

4.2

4.6

5.4

10

60

3.4

3.5

3.7

3.9

4.4

4.9

5.9

12

54

2.7

2.9

3.2

3.5

4.1

5.2

6.8

18

100

12

13

14

15

17

21

26

60

310

6.2

6.6

7.2

7.8

9.2

11

14

31

147

6.2

6.6

7.2

7.8

9.2

11

14

31

147

3.8

4.1

4.4

4.8

5.5

6.5

7.9

15

65

1.3

2.7

2.9

3.0

O 1 o. 1 

3.3

3.8

4.4

7.9

40

2.8

2.9

3.1

3.2

3.4

3.9

4.7

8.7

38

1.8

2.0

2.2

2.4

2.7

3.5

4.7

13

66

8.6

9.4

10

11

12

15

19

43

208

4.4

4.8

5.2

5.5

6.2

8.0

10

23

101

4.4

4.8

5.2

5.5

6.2

8.0

10

23

101

2.8

3.0

3.2

3.4

3.8

4.9

6.0

12

46

2.0

2.2

2.3

2.4

O K &,a 

2.7

3.0

3.6

6.0

22

2.2

2.3

2.4

2.5

2.7

3.1

3.7

6.6

23

1.1

1.2

1.3

1.4

1.7

2.1

3.2

8.0

37

5.7

6.3

6.7

7.3

8.2

10

14

30

120

2.9

3.2

3.4

3.7

4.2

5.2

7.2

16

62

2.9

3.2

3.4

3.7

4.2

5.2

7.2

16

62

1.8

2.0

2.1

2.3

2.6

3.3

4.4

8.9

29

5.0

1.6

1.7

1.8

2.1

2.4

2.7

4.4

11

1.6

1.8

1.8

1.9

2.1

2.4

2.8

4.7

12

0.62

.68

.74

.81

1.0

1.3

1.8

4.7

19

3.7

4.0

4.2

4.6

5.5

6.9

8.6

19

65

1.7

1.9

2.0

2.3

2.8

3.5

4.4

10

34

1.7

1.9

2.0

2.3

2.8

3.5

4.4

10

34

1.0

1.1

1.2

1.4

1.7

2.2

2.7

6.0

17

10

1.4

1.5

1.5

1.8

2.0

2.3

3.9

8.5

1.4

1.5

1.5

1.6

1.8

2.0

2.4

4.1

9.4

0.45

.51

.55

.61

.74

.90

1.2

3.8

14

2.9

3.2

3.4

3.7

4.3

5.0

6.5

16

47

1.2

1.4

1.5

1.7

2.1

2.5

3.3

8.4

25

1.2

1.4

1.5

1.7

2.1

2.5

3.3

8.4

25

0.67

.79

.85

1.0

1.2

1.5

2.0

5.0

13

20

1.1

1.2

1.3

1.5

1.7

2.0

3.4

7.1

1.2

1.2

1.3

1.4

1.5

1.7

2.0

3.4

7.9

0.38

.41

.44

.50

.55

.64

.90

2.7

10

2.5

2.6

2.8

3.1

3.4

3.8

4.8

12

37

0.90

1.0

1.1

1.3

1.5

1.8

2.4

6.4

20

0.90

1.0

1.1

1.3

1.5

1.8

2.4

6.4

20

0.48

.54

.60

.73

.85

1.0

1.5

4.0

10

30

1.0

1.0

1.1

1.4

1.5

1.8

3.1

6.3

1.0

1.1

1.2

1.3

1.4

1.5

1.8

3.1

7.0

0.33

.36

.39

.42

.46

.51

.72

2.1

8.6

2.2

2.3

2.5

2.7

2.9

3.2

4.2

10

32

0.70

.75

.90

1.1

1.2

1.4

2.0

5.3

17

0.70

.75

.90

1.1

1.2

1.4

2.0

5.3

17

0.35

.39

.47

.60

.66

.79

1.2

3.3

9.2

50

0.80

.85

.93

1.1

1.2

1.5

2.6

5.6

0.80

.86

.95

1.1

1.2

1.3

1.5

2.6

6.1

0.27

.28

.30

.33

.36

.40

.55

1.6

7.4

1.8

1.9

2.0

2.2

2.4

2.6

3.4

7.9

28

0.46

.52

.62

.76

.85

1.0

1.5

4.0

15

0.46

.52

.62

.76

.86

1.0

1.5

4.0

15

0.22

.25

.31

.38

.44

.54

.85

2.5

8.4
52 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, OALIF. 

TABLE 7. Low-flow frequency table for selected stream-gaging stations Continued

Station 

No.

4686.5

4687

4690

4695

4695. 5

Gaging station

North Fork

Ten Mile

River near

Fort Bragg.

South Fork

Ten Mile

River near

Fort Bragg.

Mattole River

near Petrolia.

North Fork

Mattole

River at

Petrolia.

Bear River at

Capetown.

Number of 

consecutive 

days

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

1

7

14

30

60

90

120

183

274

Ordinates of low-flow frequency curves, in cubic feet per second, for 

indicated recurrence intervals, in years

1.02

6.3

6.5

6.8

7.4

9.0

11

13

26

108

1.8

1.9

2.0

2.2

3.0

3.7

4.5

12

53

61

63

65

70

92

111

135

370

1,650

9.1

9.4

9.7

11

13

16

20

52

230

19

20

21

23

27

32

40

102

445

1.10

4.3

4.7

5.0

5.5

6.3

7.4

9.0

17

74

1.0

1.1

1.2

1.4

1.7

2.2

3.0

7.4

36

41

44

47

50

61

73

90

220

1.150

6.2

6.7

7.2

7.7

9.1

11

13

31

160

13

14

15

16

19

22

27

61

310

1.3

3.2

3.4

3.6

3.9

4.3

5.6

6.8

14

52

0.63

.72

.80

.87

1.0

1.5

2.0

5.2

25

29

31

34

36

41

51

65

160

810

4.4

4.7

5.1

5.5

6.2

7.7

9.6

23

110

10

11

12

13

14

16

20

46

215

2.0

2.1

2.3

2.4

2.6

3.0

3.8

5.0

10

33

0.33

.39

.43

.48

.59

.82

1.3

3.5

15

20

21

23

25

28

35

47

105

490

3.0

3.2

3.5

3.8

4.2

5.3

7.2

15

69

7.3

7.7

8.3

8.8

9.6

12

15

30

133

5.0

1.1

1.2

1.4

1.6

1.9

2.5

3.1

6.8

19

0.13

.16

.18

.23

.31

.44

.62

2.0

8.0

12

13

14

16

19

23

30

65

250

1.8

2.0

2.2

2.5

2.9

3.5

4.5

9.7

35

5.0

5.4

5.8

6.3

7.1

8.3

10

21

69

10

0.76

.90

.97

1.1

1.4

1.7

2.3

5.7

15

0.07

.09

.11

.14

.20

.26

.40

1.6

5.7

8.9

9.5

10

12

14

17

22

55

170

1.4

1.5

1.6

1.9

2.2

2.6

3.4

8.3

25

4.2

4 4

4.7

5.2

5.7

6.5

8.1

18

50

20

0.55

.62

.68

.83

.97

1.1

1.7

4.6

12

0.04

.05

.06

.08

.11

.15

.24

1.1

4.5

6.7

7.2

8.3

9.3

10

13

17

42

130

1.0

1.1

1.3

1.4

1.6

2.0

2.6

6.3

19

3.5

3.7

4.0

4.2

4.6

5.4

6.5

14

38

30

0.39

.44

.54

.68

.75

.90

1.4

3.8

11

0.02

.03

.04

.06

.07

.10

.18

.82

3.8

5.3

5.7

6.7

7.7

8.5

10

14

35

112

0.83

.89

1.0

1.2

1.3

1.6

2.2

5.3

16

3.1

3.2

3.5

3.8

4.0

4.6

5.7

12

32

50

0.22

.26

.33

.43

.50

.62

.97

2.8

9.0

0

.01

.02

.03

.04

.05

.11

.55

3.3

3.8

4.2

4.8

5.6

6.5

7.4

10

27

98

0.60

.66

.76

.87

1.0

1.1

1.6

4.1

14

2.7

2.8

3.0

3.2

3.4

3.6

4.6

9.4

28

TABLE 8. Composite low-flow frequency table

Number of consecutive 

days

1 ________ ....... ....

7 . ., 

14__.__ _-_.._____ 

SO...........................

60...- ...... ..... ....... .

90..... ................ ...

120..... ... ... ___________ .

183.... .

274. . ... _ 

Ordinates of composite low-flow frequency curves, expressed as percentiles 

of flow duration, for indicated recurrence intervals, in years

1.02

75 

74 

73 

71 

67 

63 

59 

43 

16

1.10

82 

81 

80 

78 

75 

71 

67 

51 

21

1.3

88 

87 

85 

84 

82 

77 

72 

57 

27

2.0

94 

93 

92 

91 

89 

85 

80 

64 

37

5.0

98.0 

97.5 

97.0 

96.0 

95.0 

92.0 

89.0 

73.0 

49.0

10

99.0 

98.7 

98.4 

98.0 

97.0 

95.3 

93.0 

78.0 

55.5

20

99.6 

99.5 

99.3 

99.0 

98.5 

97.5 

95.5 

84.0 

61.0

30

99.8 

99.7 

99.6 

99.3 

99.1 

98.5 

97.0 

87.0 

63.0

50

a 

6 

99.9 

99.8 

99.6 

99.4 

98.5 

91.0 

66.0

NOTE. Symbols a and 6 indicate percentiles greater than 99.9. Ordinates represented by a and b are 

discharges in cubic feet per second, where a=0.90(Q9».6) and 6=0.95(Q98.9>.
TABLES 53

TABLE 9. Summary of results of flood-frequency analysis

Station

No.

4560

4565

4570

4585

4590

4600

4610

4615

4625

4630

4640

4645

Gaging station

Napa River near St.

Helena.

Conn Creek near St.

Helena.

Dry Creek near Napa .....

Sonoma Creek at Boyes 

Hot Springs.

Petaluma River at Petaluma.

Corte Madera Creek at

Ross.

Russian River near

Ukiah.

East Fork Rnssian River

near Calpella.

Russian River near

Hopland.

Russian River near

Cloverdale.

Russian River near

Healdsburg.

Dry Creek near Cloverdale.

Drainage 

area

(sq mi)

81.4

53.2

17.4

62.2

30.9

18.1

99.7

93.0

362

502

793

87.8

Mean

annual

basinwide

precipitation

(In.)

43

37

44

45

31

40

46

40

45

44

45

50

Peak discharge for indicated

recurrence intervals

Recurrence

interval

(years)

2.33

5

10

25

50

2.33

5

10

25

50

2.33

5

10

25

50

2.33

5

10

25

50

2.33

5

10

25

50

2.33

5

10

25

50

2.33

5

10

25

50

2.33

5

10

25

50

2.33

5

10

25

50

2.33

5

10

25

50

2.33

5

10

25

50

2.33

5

10

25

50

Peak discharge, in cfs

Qc (from

individual

station

frequency

curves)

6,400

9,200

11,000

12,700

13,800

3,200

5,200

6,800

8,600

9,900

1,220

1,980

2,510

3,080

3,500

4,300 

6,200

7,700

9,600

11,000

1,080

1,410

1,630

1,820

1,930

2,020

2,740

3,180

3,600

3,880

9,900

13, 500

16, 200

19, 800

22, 000

7,670

10,600

12, 800

15,600

17,500

21, 800

33, 000

40, 500

50, 000

56,000

24,200

36, 800

47, 000

59,000

68,000

35,800

50,000

60, 500

72, 000

80,000

10, 100

15, 200

18, 000

22,000

25,500

Qr (from

regression

equation)

5,660

8,250

10,100

12, 300

13, 900

3,280

4,720

5,720

6,810

7,540

1,700

2,520

3,100

3,770

4,260

4,870 

7,150

8,830

10,800

12,200

1,660

2,360

2,810

3,260

3,530

1,540

2,250

2,750

3,300

3,600

7,320

10, 700

13,300

16, 300

18, 500

5,710

8,260

10, 100

12,200

13,600

20, 000

29,000

35, 800

43, 900

49,600

25, 100

36, 300

44, 800

54,800

61,800

37,400

54,000

66,700

81,900

92,600

7,430

11,000

13, 700

17, 000

19,500

Percent 

difference

100(Qe -Qr)

Qr

+13

+12

+9

+3-1

-2

+10

+19

+26

+31

-28

-21

-19

-18

-18

-12 

-13

-13

-11

-10

-35

-40

-42

-44

-45

+31

+22

+16

+9

+5

+35

+26

+22

+21

+19

+34

+28

+27

+28

+29

+9

+14

+13

+14

+13

-4

+1

+5

+8

+10

 4

 7

-9

-12

-14

+36

+38

+31

+29

+31
54 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF. 

TABLE 9. Summary of results of flood-frequency analysis Continued

Station

No.

4670

4675

4680

4685

4690

Gaging station

Russian River near

Guerneville.

South Fork Gualala

River near Annapolis.

Navarro River near

Navarro.

Noyo River near Fort

Bragg.

Mattole River near

Petrolia.

Drainage 

area

(sqmi)

1,340

161

303

106

240

Mean

annnal basinwide

precipitation

(in.)

45

58

53

56

92

Peak discharge for indicated

recurrence intervals

Recurrence

interval

(years)

2.33

5

10

25

50

2.33

5

10

25

50

2.33

5

10

25

50

2.33

5

10

25

50

2.33

5

10

25

50

Peak discharge, in cfs

Qe (from

individual

station

frequency

curves)

50,200

68,000

80,000

93,000

102,000

25,500

35,400

43,000

52,200

59,000

16,800

29,000

41,000

57,000

71, 500

7,300

11,500

15,900

22, 400

28,000

30,800

46,000

58,700

74,700

89,000

Qr (from

regression

equation)

56,900

82,000

101,000

125,000

141, 000

14,800

22,200

28,100

35,600

41,600

21,800

32,200

40,400

50,600

58,400

10, 000

15,000

18, 900

23, 900

27, 700

38,900

61,000

80,800

109,000

134,000

Percent 

difference

100(Qe -Qr)

Qr

-12

-17

-21

-26

-28

+72

+59

+53

+47

+42

-23

-10

+1

+13

+22

-27

-23

-16

-6

+1

-21

-25

-27

-31

-34

TABLE 10. Multiple-regression equations and associated statistics for peak discharges 

at selected recurrence intervals

Recurrence interval 

(years)

2.33............ ...........

5 

10... _____ __ _.... ....

25..................... ___ ..

SO............................

Multiple-regression equation

Q2.33-0.922/10.800 pi .38_____ __ . .......

Qs =0.929 .40,794 pi. 49 __ __ ..... 

Qio= 0.793/10. pi .59. ...............

Q25=0.580 /10.796 PI .«.. _____ . _____ -

Q6o=0.416/io. >pi.84__.. ______ _ ....

Coefficient 

of multiple 

correlation

0.972 

.976 

.978 

.977 

.976

Standard error of 

estimate

Logarithmic units

0.128 

.119 

.115 

.119 

.124

Percent

30 

28 

26 

28 

29

NOTE. Q=discharge, in cubic feet per second. 

A=drainage area, in square miles. 

P=mean annual basinwide precipitation, in inches.
TABLES 55

TABLE 11. Comparison of maximum recorded peak discharge and Qso computed from

regression equation

Station

No.

4560

4565

4570

4580

4582

4585

4590

4600

4605

4608

4609.2

4610

4615

4625

4627

4630

4632

4639

4639.4

4640

4645

4652

4658

4670

4672

4675

4675. 5

4676

4678

4680

4680.1

4680.7

Gaging Station

Napa River near St.

Helena.

Conn Creek near St.

Helena.

Dry Creek near

Napa.

Napa River near

Napa.

Redwood Creek

near Napa.

Sonoma Creek at

Boyes Hot

Springs.

Petaluma River at

Petaluma.

Corte Madera Creek

atRoss.

Nicasio Creek near

Point Reyes Station.

Walker Creek near

Tomales.

Salmon Creek at

Bodega.

Russian River near

Ukiah.

East Fork Russian

River near Calpella.

Russian River near

Hopland.

Feliz Creek near

Hopland.

Russian River near

Cloverdale.

Big Sulphur Creek 

near Cloverdale.

Maacama Creek

near Kellogg.

Franz Creek near

Kellogg.

Russian River near

Healdsburg.

Dry Creek near

Cloverdale.

Dry Creek near

Geyserville.

Santa Rosa Creek

near Santa Rosa.

Russian River near

Guerneville.

Austin Creek near

Cazadero.

South Fork Gualala

River near

Annapolis.

North Fork Gualala

River near

Gualala.

Garcia River near

Point Arena.

Rancheria Creek

near Boonville.

Navarro River near

Navarro.

Albion River near

Comptche.

South Fork Big

River near

Comptche.

Drainage

area

(so. mi)

81.4

53.2

17.4

218

9.81

62.2

30.9

18.1

36.2

37.1

15.7

99.7

93.0

362

31.1

502

82.3

43.4

15.7

793

87.8

162

12.5

1,340

63.1

161

39.2

98.5

65.6

303

14.4

36.2

Mean

annual

basinwide

precipitation

(in.)

43

37

44

41

35

45

31

40

38

40

36

46

40

45

47

44

52

56

42

45

50

50

48

45

65

58

67

64

52

53

57

50

Period of

record

1929-32,

1939-65 11929-45

1951-65

1929-32,

1959-65

1958-65

1955-65

1948-63

1951-65

1953-60

1959-65

1962-65

1911-13

1952-65

1941-65

1939-65

1958-65

1951-65

1957-65

1958-65

1955-65

1939-65

1941-65

1959-65

1959-65

1939-65

1959-65

1950-65

1951-56

1951-56,

1962-65

1959-65

1950-65

1961-65

1960-65,

Maximum discharge

during period of record

Date

Dec. 22,1955

Feb. 27,1940

Feb. 28,1958

Jan. 31,1963

Jan. 31,1963

Dee. 22,1955

Dec. 22,1955

Dec. 22,1955

Dec. 22,1955

Feb. 13,1962

Jan. 31,1963

Dec. 22,1964

Dec. 22,1964

Dec. 22,1964

Dec. 22,1964

Dec. 22,1964

Dec. 22,1955

Dec. 22,1964

Dec. 22,1955

Dec. 22,1964

Dec. 22,1964

Dec. 22,1964

Feb. 8, 1960

Dec. 23,1964

Feb. 13,1962

Dec. 22,1955

Dee. 22,1955

Dee. 22,1955

Dec. 22,1964

Dec. 22,1955

Dec. 21,1964

Dec. 22,1964

Qma*

(cfs)

12,600

7,700

3,460

16,900

1,330

8,880

1,860

3,620

9,010

3,430

1,430

19,500

18,800

2 57, 500

6,080

2 67, 100

20,000

8,920

4,130

'81,400

18,100

32,900

3,200

8101,000

15,100

55,000

11,900

26,300

20,000

64,500

2,050

8,200

Quo

from regression

equation

(cfs)

13,900

7,540

4,260

27,900

1,770

12,200

3,530

3,690

5,830

6,510

2,710

18,500

13,600

49,600

7,620

61,800

19,900

13,700

3,600

92,600

19,500

31,800

3,840

141,000

24,300

41,600

17,600

33,600

16,600

58,400

5,900

9,650

Ratio,

Qma */

QM

0.91

1.02

.81

.61

.75

.73

.53

.98

1.55

.53

.53

1.05

1.38

1.16

.80

1.09

1.00

.65

1.15

.88

.93

1.03

.83

0.72

.62

1.32

.68

.78

1.20

1.10

.35

0.85

See footnotes at end of table.
56 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

TABLE 11. Comparison of maximum recorded peak discharge and Qso computed from 

regression equation Continued

Station 

No.

4681 

4685 

4686

4690 

4695

Gaging Station

Big Elver near 

Mendocino. 

Noyo River near 

Port Bragg. 

Middle Pork Ten 

Mile River near 

Port Bragg. 

Mattole River near 

Petrolia. 

North Fork Mattole 

River at Petrolia.

Drainage 

area 

(sqmi)

152 

106 

33.3

240 

37.6

Mean 

annual 

basinwide 

precipitation 

(in.)

52 

56 

58

92 

82

Period of 

record

1951-56 

1951-65 

1964-65

1911-13, 

1950-65 

1951-57

Maximum discharge 

during period of record

Date

Dec. 22,1955 

Dec. 22,1964 

Dec. 21,1964

Dec. 22,1955 

Dec. 22,1955

Qma*

(cfs)

31,300 

24, 000 

5,670

90,400 

9,600

Qm 

from regression 

equation 

(cfs)

32,400 

27,700 

11,800

134,000 

24,700

Ratio,

Qmax/

Qso

0.97

.87 

.48

.67 

.39

1 Regulated by Lake Hennessey after 1945.

2 Adjusted for reservoir regulation by Lake Mendocino on the basis of provisional computations by U.S. 

Army Corps of Engineers.
TABLE 12. High-flow frequency data for selected stream-g

[Discharge, in cubic feet per second, from individual station freque

Station 

No.

4560 

4565 

4570 

4285 

4590 

4600

Gaging station

Napa River near St. Helena _____ -

Sonoma Creek at Boyes Hot Springs. ..

Drainage 

area 

(sq mi)

81.4 

53.2 

17.4 

62.2 

30.9 

18.1

Mean 

annual 

basinwide 

precipitation 

(in.)

43 

37 

44 

45 

31 

40

Recurrence 

Interval 

(years)

2.33 

5 

10 

25 

50

2.33 

5 

10 

25 

50

2.33 

5 

10

25 

50

2.33 

5 

10

25 

50

2.33 

5 

10 

25 

50

2.33

5 

10 

25 

50

Mean discharge, a

n

1

3,410 

5,190 

6,610 

8,420 

9,780

1,330 

2,090 

2,700 

3,470 

4,060

620 

980 

1,260 

1,600 

1,870

1,960 

3,000 

3,980 

5,400 

6,760

660 

960 

1,210 

1,520 

1,760

880 

1,340 

1,710 

2,180 

2,540

3

2,030 

3,170 

4,080 

5,210 

6,090

800 

1,260 

1,710 

2,270 

2,690

380 

590 

760 

970 

1,130

1,180 

1,860 

2,400 

3,100 

3,630

410 

630 

800 

1,020 

1,200

550 

840 

1,080 

1,380 

1,600

7

1,200 

1,880 

2,410 

3,100 

3,640

520 

820 

1,050 

1,360 

1,580

240 

390 

520 

690 

830

800 

1,250 

1,670 

2,290 

2,830

260 

410 

535 

690 

800

350 

530 

680 

900 

1,070

15

810 

1,250 

1,600 

2,050 

2,380

330 

530 

690 

900 

1,060

170 

260 

335 

425 

495

560 

850 

1,090 

1,400 

1,620

178 

287 

370 

470 

550

220 

350 

450 

580 

680
TABLE 12. High-flow frequency data for selected stream-gaging 

Station 

No.

4610 

4615 

4625

4630 

4640 

4645

Gaging station

East Fork Russian River near Calpella.

Drainage 

area 

(sq mi)

99.7 

93.0 

362

502 

793 

87.8

Mean 

annual 

basinwide 

precipitation 

(to.)

46 

40 

45

44 

45 

50

Recurrence 

Interval 

(years)

2.33 

5 

10 

25 

50

2.33 

5 

10

25 

50

2.33 

5 

10 

25 

50

2.33

5 

10 

25 

50

2.33 

5 

10 

25 

50

2.33 

5 

10 

25 

50

Mean discharge, a

n

1

4,240 

6,180 

7,820 

10,400 

12, 800

3,300 

5,050 

6,280 

7,400 

8,000

12,000 

19, 500 

25,100 

32,300 

37, 500

18,000 

25,200 

31,300 

38,800 

44,500

26,500 

39, 900 

50,000 

62,200 

70, 500

4,800 

7,300 

9,000 

10,700 

11,600

3

2,890 

3,990 

4,950 

6,420 

7,900

2,050 

3,050 

3,780 

4,530 

4,950

7,750 

12, 300 

15, 600 

19,200 

21, 200

12,000 

17,000 

21,300 

26, 200 

29,800

18,600 

28,500 

36, 000 

44,300 

49,400

3,630 

5,580 

7,100 

8,810 

9,990

7

2,010 

2,900 

3,630 

4,600 

5,380

1,320 

1,990 

2,500 

3,030 

3,340

5,000 

7,620 

9,800 

12,600 

14, 600

7,500 

10, 600 

13, 100 

16,200 

18,600

12, 400 

17,800 

22, 400 

28,000 

32,400

2,000 

2,990 

3,790 

4,800 

5,550

15

1,330 

1,850 

2,280 

2,820 

3,240

880 

1,330 

1,620 

1,830 

1,900

3,480 

5,010 

6,200 

7,420 

8,200

5,100 

7,020 

8,600 

10, 400 

11,600

8,500 

12, 200 

14, 600 

17,000 

18,200

1,270 

1,800 

2,250 

2,790 

3,220
4670

4675

4680

4685

4690

South Fork Qualala Rivernear Annapolis. 

1,340

161

303

106

240

45

58

53

56

92

2.33

5 

10 

25 

50

2.33

5 

10 

25 

50

2.33

5 

10 

25 

50

2.33

5 

10 

25 

50

2.33

5 

10 

25 

50

39,200

57,000 

71, 100 

86, 200 

95, 100

11,600

17,500 

21, 700 

25,600 

27,500

12,200

19,200 

25, 600 

34, 500 

41,500

5,100

8,100 

10, 800 

14, 400 

17, 100

18, 200

24, 600 

30,200 

38,500 

45, 000

30,290

45, 200 

57, 500 

73, 000 

84,900

7,060

10, 200 

12, 800 

16, 000 

18, 400

8,700

12, 100 

14, 800 

18,200 

20,800

3,320

4,950 

6,220 

7,720 

8,750

16,200

22,100 

26, 500 

32, 000 

36,200

20, 400

30, 600 

39,500 

51, 300 

61,000

4,500

6,620 

8,210 

10,200 

11,500

5,580

7,810 

9,700 

12,000 

13, 800

2,150

3,020 

3,750 

4,650 

5,320

11,800

15, 800 

19, 000 

23, 200 

26,300

14,000

20,000 

25, 000 

31, 300 

36,000

3,100

4,100 

4,800 

5,650 

6,300

3,600

4,830 

5,810 

7,090 

8,020

1,410

1,950 

2,380 

2,940 

3,360

7,900

10, 600 

12, 600 

14, 800 

16, 200
60 SURFACE WATER, SAN FRANCISCO BAY TO EEL RIVER, CALIF.

TABLE 13. Multiple-regression equations and associated statistics for high flows of 

various durations at selected recurrence intervals

Number of 

consecutive 

days

1. .............. .

3. . 

7.... 

15. _ .-- 

30... 

60... 

90.... 

120.... . .

150.. . . 

183 _ .

974.

Recurrence 

interval 

T (years)

2.33

5 

10 

25 

50

2.33 

5 

10

25 

50

2.33

5 

10 

25 

50

2.33 

5 

10 

25 

50

2.33 

5

10 

25 

50

2.33 

5

10 

25 

50

2.33

5 

10 

25 

50

2.33

5 

10 

25 

50

2.33

5 

10 

25 

50

2.33

5 

10 

25 

50

2.33 

5 

10 

25 

50

Values of constants In 

multiple-regression 

equation: Qr=aAbp°t

a

0.341 

.657 

1.054 

1.041 

1.172

.070 

.171

.284 

.438 

.557

.032 

.087 

.148 

.236 

.308

.022 

.070 

.123 

.196 

.258

.0109 

.032 

.058 

.110 

.162

.0039 

.0177 

.042 

.104 

.167

.0022 

.0122 

.036 

.090 

.155

. 00130 

.0085 

.024 

.063 

.109

.00078 

.0053 

.0161 

.043 

.072

.00071 

.0044 

.0105 

.021 

.030

.00040 

.0025 

.0062 

.0154 

.024

b

0.928 

.920 

.915 

.908 

.898

.960 

.953 

.949 

.941 

.934

.968 

.952 

.946 

.937 

.932

.975 

.952 

.940 

.926 

.913

1.002 

.982 

.974 

.965 

.959

1.018 

.993 

.981 

.966 

.958

1.039 

1.008 

.988 

.972 

.964

1.036 

1.015 

.997 

.980 

.965

1.046 

1.016 

.996 

.976 

.961

1.032 

1.019 

1.008 

.988 

.972

1.024 

1.005 

.996 

.988 

.981

1.327 

1.272 

1.222 

1.292 

1.311

1.591 

1.473 

1.407 

1.363 

1.347

1.671 

1.534 

1.466 

1.419 

1.394

1.655 

1.480 

1.406 

1.356 

1.334

1.705 

1.554 

1.473 

1.381 

1.325

1.857 

1.601 

1.451 

1.294 

1.218

1.919 

1.626 

1.439 

1.284 

1.193

2.011 

1.664 

1.485 

1.320 

1.234

2.084 

1.740 

1.542 

1.380 

1.303

2.078 

1.736 

1.591 

1.498 

1.468

2.141 

1.801 

1.643 

1.479 

1.408

Coefficient 

of 

multiple 

correlation

0.991 

.990 

.989 

.992 

.992

.992 

.992 

.992 

.992 

.992

.994 

.994 

.995 

.994 

.994

.995 

.995 

.995 

.995 

.994

.995 

.995 

.995 

.995 

.995

.994 

.996 

.997 

.997 

.997

.995 

.996 

.997 

.997 

.997

.994 

.996 

.996 

.996 

.996

.994 

.996 

.997 

.997 

.997

.993 

.994 

.995 

.996 

.996

.994 

.995 

.996 

.996 

.997

Standard error of 

estimate

Logarithmic 

units

0.080 

.083 

.087 

.076 

.075

.080 

.078 

.078 

.077 

.077

.070 

.066 

.064 

.065 

.067

.065 

.063 

.061 

.060 

.064

.068 

.063 

.061 

.060 

.065

.073 

.059 

.051 

.051 

.051

.071 

.059 

.053 

.051 

.050

.078 

.064 

.057 

.054 

.055

.080 

.062 

.054 

.048 

.048

.084 

.071 

.064 

.057 

.054

.079 

.066 

.060 

.055 

.052

Percent

18 

19 

20 

18 

17

19 

18 

18 

18 

18

16 

15 

15 

15 

16

15 

15 

14 

14 

15

16 

15 

14 

14 

15

17 

14 

12 

12 

12

16 

14 

12 

12 

11

18 

15 

13 

12 

13

18 

14 

12 

11 

11

19 

16 

15 

13 

12

18 

15 

14 

13 

12

Range of percentage differences between 

individual 

station discharges and 

discharges 

computed from 

regression 

equations

-20 to +40 

-23 to +30 

-25 to +38 

-26 to +28 

-26 to +28

-25 to +40 

-22 to +44 

-21 to +46 

-19 to +44 

-18 to +42

-21 to +39 

-18 to +35 

-17 to +33 

-17 to +35 

-18 to +37

-21 to +32 

-18 to +35 

-17 to +35 

-16 to +36 

-15 to +37

-23 to +29 

-20 to +31 

-21 to +32 

-21 to +30 

-21 to +31

-24 to +31 

 19 to +21 

-18 to +18 

-20 to +17 

-15 to +20

-22 to +31 

-16 to +26 

-14 to +25 

-15 to +25 

-15 to +24

-25 to +34 

-21 to +29 

-20 to +26 

-19 to +23 

-18 to +20

-24 to +33 

-20 to +31 

-18 to +28 

-16 to +24 

-16 to +21

-26 to +36 

-24 to +33 

-21 to +31 

-16 to +28 

 15 to +25

-23 to +35 

-20 to +34 

-19 to +34

-18 to +31 

-17 to +28

Where QT=Discharge, in cubic feet per second, corresponding to recurrence interval of T years; 

A=Drainage area, in square miles; 

P=Mean annual basinwide precipitation, in inches; 

a, 6, and c are constants.

o