Of Water by Phreatophytes 

And Hydrophytes Near 

Yuma, Arizona

GEOLOGICAL SURVEY PROFESSIONAL PAPER 486-F
Studies of Consumptive Use 

Of Water by Phreatophytes 

And Hydrophytes Near 

Yuma, Arizona

By CHARLES C. McDONALD and GILBERT H. HUGHES

WATER RESOURCES OF LOWER COLORADO RIVER SALTON SEA AREA

GEOLOGICAL SURVEY PROFESSIONAL PAPER 486-F

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1968
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

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

Washington, D.C. 20402 - Price 35 cents (paper cover)
CONTENTS

Page

Abstract___....__....___..__....._...____.___ T ___________......_ Fl

Introduction.______________________________________________________________ 1

Imperial Camp site.________________________________________________________ 3

Arrowweed_ __________________________________________________________ 4

Atriplex. ______________________________________________________________ 7

Bare soil.______________________________________________________________ 9

Bermuda grass._______________ _________________________________________ 13

Relation between volume of vegetation and water use.______________________ 13

Effects of salinity.______________________________________________________ 14

Mittry Lake site...---------_________________-______________-_-_-_----_----- 15

Cattail.___________________________________________________________ 15

Effects of salinity___________________________________________________--_- 17

Fluctuations of the water table.______________________________________________ 17

Meteorological data.________________________________________________________ 19

References._______________________________________________________________ 24

ILLUSTRATIONS

Page 

FIGURE 1. Map showing sites of evapotranspiration tanks near Imperial Dam, Calif., and Mittry Lake, Ariz ______ F2

2. Map showing layout of evapotranspiration tanks at Imperial Camp, Calif...____.-_.____-----.--------- 3

3. Photographs showing arrowweed (Pluchea sericea) growing in evapotranspiration tanks at Imperial Camp,

Calif__.___________________________________________________________________________________ 4

4. Graphs showing monthly water use and volume of vegetation grown in tanks at Imperial Camp, Calif .-- 6 

5-7. Photographs of 

5. Quailbrush (Atriplex lentiformis) in evapotranspiration tanks at Imperial Camp, Calif. _______i-___ 8

6. Fourwing saltbush (Atriplex canescens) in evapotranspiration tanks at Imperial Camp, Calif _______ 10

7. Surface of bare-soil evaporation tanks at Imperial Camp, Calif. _______________________________ 11

8-10. Graphs showing 

8. Relations of annual evaporation of ground water from bare soil to depth of water table below land

surface, Ariz., Calif., Utah_____________________________________-___.----_____-__---- 12

9. Yearly water use of vegetation in tanks at Imperial Camp, Calif., 1963-66.________.__---_____-- 14

10. Specific conductance of water extracted from saturated soil samples at Imperial Camp, Calif., January

1966.____--_.________________ _____________________________________________________ 14

11. Photographs of Mittry Lake, Ariz., evapotranspiration tanks showing cattail._____-_-_-_--_--------_--- 16

12-17. Graphs showing 

12. Monthly water use and volume of cattail in tanks at Mittry Lake, Ariz._______.___-__-_____-_-_ 16

13. Diurnal fluctuations in ground-water levels, air temperature, and relative humidity, Imperial Camp,

Calif., March 1963__-____-__________________________________-__-_-___--_____-_______- 18

14. Diurnal fluctuations in ground-water levels, air temperature, and relative humidity, Imperial Camp,

Calif., Sept. 1963___._._______________________________,_______________________________ 18

15. Depth of water below land surface and amplitude of diurnal fluctuations in an area of arrowweed near

Imperial Camp, Calif.__-_--____________________-_______________-_--_-_____-__-_-_---- 19

16. Relative monthly magnitude of certain hydrologic variables near Imperial Dam, Ariz.-Calif _______ 20

17. Monthly evaporation from water surface, evapotranspiration by arrowweed, magnitude of diurnal 

fluctuations of ground-water levels, and evaporation-equivalent of short-wave solar radiation 

near Imperial Dam, Ariz.-Calif_______-_______-_____-_-___-______-___----_-_-__-_--__-- 21

in
IV CONTENTS

TABLES

Page

TABLE 1. Results of surveys of arrowweed in evapotranspiration tanks, Imperial Camp __________________________ F5

2. Monthly water use by arrowweed in tanks at Imperial Camp._______________________________________ 7

3. Volume of Atriplex in evapotranspiration tanks at Imperial Camp ____________________________________ 7

4. Monthly water use by Atriplex in tanks at Imperial Camp.__________________________________________ 9

5. Sieve analyses of soil in bare-soil tanks at Imperial Camp__________________________________________ 9

6. Monthly evaporation of ground water from bare-soil tanks at Imperial Camp __________________________ 12

7. Monthly water use by bermuda grass in tanks at Imperial Camp__________________________-________._ 13

8. Volume of cattail in evapotranspiration tanks at Mittry Lake__________________--_-_____-----____---_ 16

9. Monthly water use by cattail in tanks at Mittry Lake______-________---_---_-_-_---___-__-----_---_ 17

10. Meteorological data for Mittry Lake site ______________-___--_______--____---_--_-__-_------.__---- 21

11. Meteorological data for Yuma Proving Ground, Ariz________-_______________--__-____---_-_____--- 22

12. Meteorological data for Imperial Camp__._______________________________________________________ 23
WATER RESOURCES OF LOWER COLORADO RIVER SALTON SEA AREA

STUDIES OF CONSUMPTIVE USE OF WATER BY PHREATOPHYTES AND HYDROPHYTES

NEAR YUMA, ARIZONA

By CHAELES C. MCDONALD and GILBERT H. HUGHES

ABSTRACT

Studies of transpiration by several species of flood-plain 

vegetation and evaporation from water surfaces and bare soil 

were carried out near Yuma, Ariz., during a 6-year period, 

1961-66. Arrowweed, fourwing saltbush, quailbrush, and bermuda grass were grown under controlled conditions in large 

tanks about 1,000 square feet in area, and cattail was grown 

in tanks 100 square feet in area. The larger tanks were also 

used for studies of evaporation from bare soil. Evaporation 

from water surfaces was measured by two standard U.S. 

Weather Bureau Class "A" pans and by a ground-level tank 

which was 10 by 10 feet. Related meteorological observations 

were made near the sites, and those of nearby meteorological 

stations at Yuma Proving Ground and Yuma, Ariz., were used.

The sites were on the flood plain of the Colorado River below 

Imperial Dam. Although the immediate area had a moderately 

dense cover of preponderantly arrowweed, the environment was 

principally desert, with high temperatures, low humidity, and 

a long growing season. Rates of evaporation and transpiration 

for this area rank among the highest in the United States.

Annual consumptive use by the several species increased with 

the volume of vegetation, but the consumptive use per unit 

volume decreased as the plants approached maturity. Depth to 

the water table strongly influenced evaporation from bare soil; 

for water table depths of 2.0-4.0 feet, evaporation varied from 

3 to 20 inches yearly. Water table depths moderately influenced 

transpiration by Atriplex, although the depth of the tanks did 

not permit the water table to be held at sufficient depth to 

create substantial moisture stress. Average yearly water use 

for the vegetation was as follows:

Average

Depth to yearly 

water table water use, 

in feet in inches

Arrowweed (Pluchea sericea)... 5. 5 96 

Quailbrush (Atriplex lentiformis). 3. 5-5. 5 44 

Fourwing saltbush (Atriplex 3. 5-5. 5 38

canescens). 

Bermuda (Cynodon dactylon) _ _ 3. 5 73

INTRODUCTION

Native flood-plain vegetation consumes a large 

amount of water along many river channels in the arid 

southwestern United States. The vegetation is preponderantly phreatophytes that obtain most of their 

moisture directly from ground water. They consume a

significant part of the available water supply in the 

western States; nearly 25 million acre-feet (Eobinson, 

1952) may be consumed yearly by more than 16 million 

acres of phreatophytes growing mostly on river flood 

plains. In six States Arizona, California, Colorado, 

Nevada, New Mexico, and Utah the area of phreatophytes was estimated by the Select Committee of the 

U.S. Senate (I960) to be 7 million acres, with an estimated annual consumptive use of 10-12 million acrefeet of water. In the basins of the Colorado Eiver and 

its tributaries below Hoover Dam, the annual consumptive use by phreatophytes was estimated by the Select 

Committee to be 1.2 million acre-feet. In the Colorado 

Eiver valley between Davis Dam and and the international boundary, about 200 miles in length, preliminary estimates (U.S. Bureau of Reclamation, 1964) 

indicated that 167,000 acres of phreatophytes and 

hydrophytes consumed 570,000 acre-feet of water 

yearly.

Water consumed by phreatophytes, such as saltcedar, 

arrowweed, willow, mesquite, and Atriplex, generally 

produces benefits of lower economic value than would 

be produced if the water were used for agriculture and 

domestic purposes; thus salvage of water by eradication 

of such vegetation in certain areas has considerable appeal. Control measures have been carried out in several 

areas. An outstanding example is the extensive clearing 

of saltcedar in the flood plain of the Eio Grande Eiver 

in southern New Mexico (U.S. Senate, 1960).

The quality of water available for salvage is the difference between the evapotranspiration from the area 

before modification of the vegetation and the evapotranspiration from the area after modification of the 

vegetation. Estimates of such losses, however, are subject to large errors. Eates of water use by vegetation 

vary greatly because the rates are influenced by many 

factors, including the types of vegetation, availability 

of water, wind movement, relative humidity, growth 

rates, solar radiation, and soil characteristics. Several

Fi
F2 WATER RESOURCES OF LOWER COLORADO RIVER SALTON SEA AREA

species of plants of different size and growth patterns 

may intermingle, thus complicating the problem of determining the water use in a given area. Furthermore, 

eradication of the vegetation does not assure that the 

water loss by evapotranspiration will be stopped. For 

example a rise in the water levels resulting from the lack 

of vegetation may promote increased evaporation from 

wet soil and rapid regrowth of plants. Estimates of 

evapotranspiration from the area after modification 

of the vegetation requires an appraisal of the altered 

hydrologic regimen, including the efficiency of any 

works constructed to capture the salvaged water.

Preliminary estimates by the U.S. Bureau of Reclamation (1964) suggest that in the Colorado River valley 

below Davis Dam, consumptive use by phreatophytes 

may be reduced by more than 250,000 acre-feet yearly by 

clearing flood-plain vegetation and improving the river 

channel.

Measurement of consumptive use by native vegetation 

under natural growing conditions is not readily accomplished. Many different methods for deriving a suitable 

index for consumptive use have been devised and experimentation is still in progress (Robinson, 1964), but 

all methods used to date seem to be deficient in some 

way and none provide results that are directly applicable to the determination of consumptive use by large 

areas of heterogeneous native phreatophytes. The influence of such diverse factors as vegetation density, advected energy, and the availability of water on the rate 

of water use have not been reliably determined.

Evapotranspirometers are tanks in which vegetation 

is grown under controlled conditions in extensive stands 

of native vegetation. They permit precise measurement 

of water consumed by vegetation in the tanks and provide a reasonable approximation of the natural environment. These attributes have resulted in their frequent 

use in the past. In recent studies, tanks of large size, up 

to 1,000 square feet in area (Robinson and Bowser, 

1959), have been utilized to study a more representative 

sample of the larger shrub-type plants. Still larger 

phreatophytes, such as mature mesquite and willow, 

cannot be readily grown in tanks. The diversity and 

range of factors affecting evapotranspiration in natural 

environments are so great and the relations between 

factors so complex that it is impracticable to try to 

completely reproduce all factors in tanks. Available 

tank data, therefore, usually represent only a fraction 

of the range of natural conditions affecting consumptive 

use even for the principal species. Nevertheless, the 

tank method was considered to have sufficient applicability to justify its use in studies of consumptive use in 

the lower Colorado River valley.

The first phase of the joint study by the Geological

Survey and Bureau of Reclamation, as described in this 

report, was carried out during the years 1961-1966. Two 

groups of evapotranspiration tanks (one group near 

Imperial Camp, Calif., and one at Mittry Lake, Ariz., 

see fig. 1) were installed in the Colorado River flood 

plain, about 20 miles north of Yuma, Ariz. Operation 

of the tanks at the 1 Mittry Lake site was discontinued 

on December 31, 1964, but operation of the tanks at 

Imperial Camp is expected to be continued until 1968 

as a part of the second phase of the study.

Most of the area shown in figure 1, which is outlined 

approximately by Imperial and Laguna Dams, the AilAmerican Canal and the Gila Gravity Main Canal, is 

occupied by the river channel, shallow lakes, and the 

flood plain. Phreatophytes occupy nearly all of the flood 

plain and hydrophytes grow in much of the shallow 

water. The largest body of open water in the area is 

Mittry Lake.

32°50' Impe

Imperial C

2000 4000 FEET

FIGURE 1. Sites of evapotranspiration tanks near Imperial Dam, 

Calif, and Mitty Lake, Ariz., about 20 miles north of Yuma, Ariz.
CONSUMPTIVE USE OF WATER BY PHREATOPHYTE& AND HYDROPHYTES NEAR YUMA, ARIZONA F3

The tanks were constructed by the Bureau of 

Reclamation, Yuma Projects Office, and were instrumented and operated by the Geological Survey. Mr. 

G. H. Hughes was in direct charge of operation of the 

tanks from April 1961 to July 1965; Mr. E. H. Westphal operated the tanks from August 1965 to July 1966, 

and Mr. O. M. Grosz from August to December 1966. 

The entire study was under the general supervision of 

C. C. McDonald, project hydrologist. Water and power 

for the operations were provided by the Imperial Irrigation District; their cooperation contributed greatly 

to the tank experiments.

IMPERIAL CAMP SITtf

The Imperial Camp site is in an extensive area of 

vegetation, which is preponderantly arrowweed of 

moderately uniform height, density, and vigor. The 

environment is representative of much of the Colorado 

River flood plain where arrowweed and A triplex are 

the dominant vegetation types. Some of the vegetation 

around the tanks was destroyed in the construction 

phase but was restored afterwards by transplantation 

so that a complete cover of similar-vegetation surrounded each tank.

Three tanks were planted with arrowweed (Pluchea 

sericea), and three with Atriplex (lentiformis and 

canescens) in 1961. Three tanks were used to measure 

evaporation from bare soil during 1961-64 but were 

planted with bermuda grass (Cynodon dactylon) in 

1965. Individual tanks were separated by about 60 feet 

of vegetation similar to that grown in the tanks, and 

each group of three tanks was separated from the other 

groups by about 300 feet (fig. 2).

The tanks at Imperial Camp were constructed by lining an excavation with a watertight plastic membrane 

in a manner similar to that described by Robinson and 

Bowser (1959). The sites were dug to the desired dimensions without shoring, the bottom was carefully 

smoothed, and all rocks and other obstructions that 

might puncture the membrane were removed. A sheet of 

polyvinylchloride 0.022-inch thick was then placed in 

the excavation, and the sides were brought to the ground 

surface as the soil was replaced, thus forming a flatbottomed tank with vertical sides. The soil removed by 

excavation was replaced in the tanks without deliberate 

mixing or selection. The soil at the sites of the several 

tanks varied to some extent, but in general it consisted 

of fine sand, river silt, and minor amounts of clay.

The water-feed system, consisting of three parallel 

2-inch perforated plastic pipes connected to a 4-inch 

riser, was placed in a 6-inch blanket of sand at the bottom of the tank. An observation well of 1^-inch pipe, 

about 5 feet from the feed line, permitted readings of

Atriplex

| 2 | | 3

Arrowweed

D

Weather station

I 1 I I 2 | | 3 | 

Bare soil and Bermuda grass

FIGURE 2. Layout of evapotranspiration tanks at Imperial Camp, 

Calif.

the water level and provided access for the electrical 

contacts which activated the automatic water-feed controls. The quantity of water added to each tank was 

measured by a totalizing meter that had to be read at 

specified times. Changes in the moisture content of the 

soil above the water table were measured with a soilmoisture meter. The meter recorded the return of fast 

neutrons that were emitted by a 5 millicurie radium 

element and subsequently reflected by hydrogen atoms 

in the soil moisture. Access for the probe was provided 

by a thin-walled steel tube, 1.625 inches in diameter that 

was plugged at the bottom and that extended to a depth 

below the lowest expected water level in the tank. The 

moisture content of each tank was computed at least 

once each month from readings of the moisture content
F4 WATER RESOURCES OF LOWER COLORADO RIVER SALTON SEA AREA

of the soil at 0.5-foot intervals as the probe was lowered 

into the access tube.

ARRQWWEED

In May 1961, arrowweed was planted in three tanks, 

each of which was 32 by 32 by 7 feet; but because of hot 

weather and high soil salinity, survival was poor. Additional transplanting in January to March 1962 resulted in better survival but good growth and complete 

vegetal cover were not achieved until 1963, after the 

tanks had been leached to reduce the salinity of the 

soil. Leaching was accomplished by ponding water on 

the soil surface and pumping from the feed pipes.

By October 1963, all tanks had a vigorous stand of 

arrowweed about 6 feet in height, but less dense than 

most normal stands (fig. 3). Water levels were maintained about 3.5 feet below the land surface during 1962 

to promote root development but were lowered to about 

5 feet during 1963 and 5.5 feet during 1964-66.

Consumptive use by phreatophytes is known to be 

roughly related to the volume of transpiring foliage; 

moreover, the relations are much closer for plants of 

the same species growing in similar environments. 

Methods of measuring the areal density and volume of 

vegetation for large areas have been developed by the 

Phreatophyte Subcommittee of the Pacific Southwest 

Interagency Committee and have been described by 

Horton, Robinson, and McDonald (1959). These methods utilize transects to define indices of the thickness 

and the areal extent of the canopy and of height of the 

vegetation. To aid in the application of evapotranspirometer data to other areas, careful measurements 

of foliage volume were made at least once each year.

D

FIGURE 3. Arrowweed (Pluchea sericea) growing in evapotranspiration tanks at Imperial Camp, Calif. A. Tank AW2 shows thin stand on Aug. 24, 

1962. Framework outlines margins of tank ; crossbars are 6 feet above ground. B. Tank AW1 on Oct. 25, 1963, following a period of 

vigorous growth. C. Detail of arrowweed in tank AW2, Sept. 18, 1964; maximum height is 11 feet. D. General view of arrowweed tanks 

toward northwest. Framework marks the location of tanks. Nov. 5, 1964.
CONSUMPTIVE USE OF WATER BY PHREATOPHYTES AND HYDROPHYTES NEAR YUMA, ARIZONA F5

Vegetation survey methods described by Horton, 

Robinson, and McDonald (1959) are commonly used 

for estimates of consumptive use. They employ an area! 

density factor to express the percentage of the area 

covered by the canopy, but they do not provide a measure of foliage density within the canopy. This factor 

may be important in evaluating the evapotranspiration 

by arrowweed. The authors believed some measure of 

foliage density within the canopy was desirable, though 

no completely satisfactory technique was found to measure it. The method used expressed as a percentage the 

relationship of the visual estimates of the density of 

segments of the foliage in the tanks to the usual density of the foliage of vigorous native stands of arrowweed. The areal extent of the canopy and the vegetation 

height were measured directly instead of by transects. 

The tanks were divided into segments varying in number from 10 to 100; the results for the segments were 

then weighted to arrive at a total for the tank. The same 

segments were used for the visual density estimates.

Results of the vegetation surveys are given in table 1: 

The area of the canopy was calculated as the sum of the 

areas covered by the outer limits of the foliage, without 

regard to density. The average height and relative 

density are weighted values for the total canopy area. 

The total volume of vegetation, without consideration 

of density of foliage, is the product of the area of the 

canopy and the average height, the equivalent volume 

is the product of the area of the canopy, the average 

height, and the relative density.

Prior to 1965, the depth of the canopy seemed to be 

about equivalent to the average height of the vegetation. The growth pattern of the arrowweed in the tanks 

and apparently also of the young native stands, was 

such that the foliage transpired throughout the height 

of the plant until the density of the foliage above was 

sufficient to provide nearly complete shading from sunlight. Where the foliage was thin, permitting moderate 

penetration of sunlight, new shoots and green leaves 

were commonly found. In 1966, however, following the 

addition of small quantities of fertilizer (commercial 

urea) to the feed water, the top foliage became so dense, 

especially in tanks AW1 and AW2, that the lower 3-3.5 

feet of the vegetation produced essentially no transpiring foliage. This denudation and lessening of new 

growth near the ground began in all tanks during 1965, 

but the condition became more manifest in 1966.

Measurements of the vegetation, especially the density, are highly subjective. Differences in successive surveys should be expected, even though they were made 

by the same individual. Moreover, foliage density of 

arrowweed can increase rapidly during periods of vig287-538 O 68 2

TABLE 1. Results of surveys of arrowweed in evapotranspiration 

tanks, Imperial Camp, Calif.

'rank area, in square feet, for AW1,992; AW2,999;. and AW3,1,000. Depth of canopy 

Sept. 15 1966,for tank AW1, 5.0 feet; AW2,5.0 feet; and AW3, 4.5 feet]

Date of survey

Area of Average Average Equivalent

canopy height relative volume

(square (feet) density (cubic

feet) (percent) feet)

AW1

Dec. 13, 1962_ 

July 11, 1963.. 

Oct. 8, 1963 . 

Sept. 24, 1964. 

Aug. 6, 1965 __ 

Sept. 15, 1966.

331

455

675

952

1,010

1,080

2.8 

4.6 

6. 1 

7.3

8. 1 

8.4

57

85

77

75

75

95

520

1,770

3,080

5,220

6, 110

8,620

AW2

Dec. 13, 1962_ 

July 11, 1963.. 

Oct. 8, 1963._. 

Sept. 24, 1964. 

Aug. 6, 1965_ _ 

Sept. 15, 1966.

293

347

486

982

1,020

1,060

3.9 

5. 5 

5.9

7. 1 

8.2 

8.2

39

65

72

77

67

97

440

1,250

2,090

5,340

5,580

8,420

AW3

Dec. 13, 1962_ 

July 11, 1963.. 

Oct. 8, 1963... 

Sept. 24, 1964. 

Aug. 6, 1965 __ 

Sept. 15, 1966.

351

583

617

998

1,060

996

4. 1

5. 1

6. 1 

7.6

8. 1

7.8

49

85

78

89

68

77

710

2,540

2,940

6,760

5,880

5,980

orous growth or decline quickly as a result of dropping 

of leaves during periods of reduced vigor.

Some differences in the vigor and rate of growth of 

vegetation in the three tanks were observed, and these 

differences are reflected in the results of the density 

surveys. The best early growth during 1963 occurred in 

tank AW3, but between July 11 and October 8 tanks 

AW1 and AW2 gained much more volume than tank 

AW3. Nevertheless, by September 24, 1964, vegetation 

in tank AW3 was still larger and more vigorous than 

that in the other two tanks. During the spring of 1964, 

the arrowweed in tanks AW2 and AW3 appeared to 

lose vigor: the leaves had developed a noticeable silvery 

color, which disappeared by midsummer. The vegetation survey of August 6,1965, showed a drop in equivalent volume of about 15 percent in tank AW3 and an 

average increase of about 10 percent in the other two 

tanks. Although part of these differences may be the 

result of inconsistencies in the surveys, the relative differences were confirmed by visual observations.

Monthly water use by arrowweed is given in table 2, 

and the averages for the three tanks are plotted in 

figure 4. These figures represent water added to the 

tanks through the supply system and do not include 

water added by precipitation on the surface. The principal interest in these studies was the net consumption
F6 WATER RESOURCES OF LOWER COLORADO RIVER SALTON SEA AREA

1 

J FMAMJ J ASON-DJ FMAMJ J ASONDJ FMAMJ J A S O N O J FMAMJ J ASON D 

1963 1964 1965 D 1966

FIGURE 4. Monthly water use and volume of vegetation grown in tanks at Imperial Camp, Calif. Dashed lines show

approximate volume changes between vegetation surveys.
CONSUMPTIVE USE OF WATER BY PHREATOPHYTES AND HYDROPHYTES NEAR YUMA, ARIZONA

TABLE 2. Monthly water use by arrowweed in tanks, excluding rainfall, in inches, Imperial Camp 

[Negative values indicate that gain in soil moisture in tank exceeded water added through supply system]

F7

1962 1963

Tank - . . AW1 AW2 AW3 AW1 AW2 1

March... _ . ____ .. .. . . _____________ ___ ..

May-. 

AprU--.. .. 

__ 7.7 5.5

June _ ____ _____ __ _ .. _ _____ 10.7 9.4

July- 10.1 11.4

October. __ __ _ - - 5.2 4.4 5.9 6.6 6.4

Total 64.5 58.7

of ground water by native vegetation, but adjustments 

for rainfall can be made if desired. Except for the rare 

storm rainfall, such as occurred during September and 

October 1963 and December 1965, precipitation did not 

add an appreciable amount of water to the water supply 

system. Figure 4 shows that water use tends to increase 

as the volume of foliage increases, but it also varies 

with other factors such as maturity of the foliage. 

These factors are discussed in the section on relation 

between volume of vegetation and water use.

ATBIPLEX

Two species of A triplex, four wing saltbush (Atriplex 

canescens) and quailbrush (Atriplex lentiformis) , commonly grow on the lower Colorado River flood plain; 

however, both species cover less than 1 percent of the 

total area occupied' by phreatophytes (U.S. Bureau of 

Reclamation, 1964). 

Sometimes Atriplex is found in areas that have such 

a deep water table that the plants probably subsist on 

soil moisture derived from surface sources; however, 

it grows more vigorously and probably consumes more 

water in areas that have a shallow water table. 

Three tanks, each approximately 1,000 square feet in 

area, and identical in design with those used for arrowweed, were planted with Atriplex in the late spring of 

1961. Quailbrush, the larger of the two species, was 

grown in two tanks, Al and A2, and fourwing saltbush 

was grown in tank A3. Young vigorous plants of both 

kinds were transplanted in the tanks and in a strip

surrounding the tanks to obtain a uniform cover of

similar vegetation within the tanks and in the

surrounding area.

Transplanting the Atriplex in 1961 was not entirely

successful, 

J 

probably 

- - */ 

because of the late season and highCZJ

soil salinity, which was described in the discussion of

the arrowweed tanks. Following leaching of the tanks CD C2

to reduce salinitv earlv in 1962. retransDlantine1 and

1964 1965 1966

1 W1 A W1 A W9 A Wt A Wl A W*> A W1 A W1 A WO A \H1

 1.9 1.9 2.3 1.2 1.4 1.8 _ . - 0.2 - . 

1.9 1.2 2.0 2.3 2.7 2.5 1.0 .7 0.7

 - 2.4 2.2 2.1 2.6 3.8 3.6 2.9 1.1 1.4

 - 5.4 5.4 6.0 5.2 6.2 4.9 2.8 4.6 3.4

f\ A GO Q 1 1O ft 11 ft in 9 OR fi 4 R ft Q Q

11.5 14.0 15.5 16.4 12.5 11.9 9.9 15.0 21.4 9.1

14.0 15.8 19.5 19.0 17.4 17.0 11.8 19.5 26.4. 9.8

12.0 14.8 18.7 17.7 16.6 13.2 10.9 20.1 21.9 10.8

9.9 13.2 15.1 14.3 12.2 10.5 8.3 14.4 15.8 9.1

7.2 8.8 10.5 10.4 9.1 9.6 6.4 9.8 10.0 7.3

5.3 5.2 6.5 6.1 1.6 .2 2.0 6.2 6.8 5.2

3.4 1.8 2.2 2.3 .1 -.2 -.2 6.0 5.1 4.1

69.7 95.1 107.8 109.4 92.8 86.6 71.6 106.1 122.8 64.8

seeding resulted in good cover both in the tanks and in 

the adjacent areas, but vigorous growth did not occur 

until after additional leaching during January and 

February 1963. 

The quailbrush grew very rapidly in 1963, and most 

of the volume of vegetation looked as if it were actively 

transpiring. Changes in the seasonal appearance of the 

vegetation are noticeable in figure 5. Green leaves were 

present throughout the foliage during 1963, but in the 

years following only the outer 2-3 feet looked as if it 

were made up of actively transpiring leaves. By 1964 

the plants had formed a complete outer dense canopy, 

with a skeletal maze of angular branching twigs lacking green f oilage underneath a structure that provides 

excellent cover for quail and other small wildlife. Quail - 

brush in the tanks and in the surrounding area seemed 

to become progressively less vigorous as it approached 

maturity during 1965 and 1966. 

The vegetation in the Atriplex tanks was surveyed 

annually using methods similar to those used in surveying the arrowweed, except that the density of the Atriplex foliage was nearly normal each time, and no adjustment for relative density had to be made. In making the 

surveys, the tank areas were divided into sections, which 

varied in number according to the density of the vegetation ; the dimensions of individual plants were taken to 

obtain the total volume. The results of these surveys are 

given in table 3.

TABLE 3. Volume, in cubic feet, of Atrivlex 

in evapotranspiration tanks, at Imperial Camp

Tank

Datfco suiTey ^ ^ ^

Pec. 13. 1962__ _____ _ 1,250 860 1,290

July 11, 1963___ ~- 4,810 5,020 2,150

Oct. 8, 1963 _____________ 5, 600 5,700 2,290

Sept. 24, 1964____ _________ 6,410 6,080 2,770

Aug. 6,1965 - - 7,210 6,840 3,080

Sept. 15, 1966_ ___________ 7, 720 7, 070 3, 740
F8 WATER RESOURCES OF LOWER COLORADO RIVER SALTON SEA AREA

D

FIGURE 5. Quallbrush (Atripleas lentiformis) In evapotranspiratlon tank A2, Imperial Camp, Calif. Framework at a height of 7 feet outlines tank. 

A. View from west, June 4, 1963, during vigorous growth period. B. In seed at end of growing season, Oct. 25, 1963. C. Mature vegetation, 

less vigorous than during previous year, with little seeding evident, Nov. 5, 1964. D. View of fill pipe, water-feed controls and soil moisture 

tube (at end of walkway), Sept. 18, 1964.

The water table in the quailbrush tanks, Al and A2, 

was held at a depth of about 3.5 feet during 1962 to 

expedite root development; then it was lowered to 5.0 

feet during 1963 and 5.5 feet during 1964. The lower 

depths were believed to be more representative of the 

natural environment of the plants. The quailbrush 

looked less vigorous in 1964 than it did in 1963, and 

the water use was significantly less. To determine 

whether growth and water use were influenced substantially by depth to the water table, the water level 

in tank A2 was raised to about 3.5 feet below the land 

surface during 1965. No change in the vegetation of A2 

was apparent, either in relation to the other tank or to 

the previous year, but \vater use increased. During 1966 

both quailbrush tanks, Al and A2, were operated with 

the water table 5.5 feet below land surface. Monthly 

water use by quailbrush for the years 196*2-66 is given 

in table 4 and plotted in figure 4.
CONSUMPTIVE USE OF WATER BY PHREATOPHYTES AND HYDROPHYTES NEAR YUMA, ARIZONA F9

TABLE 4. Monthly water use by Atriplex in tanks, excluding rainfall, in inches, Imperial Camp 

[Negative values indicate that gain in soil moisture in tank exceeded water added]

Tank.. ____________ .

January __ .. ............

February _ . . _ . .......

March... __ ______ __

April.... ....................

May. ____ . .. ..........

June __________ .....

July.-- ......... .........

October..... __ . ........

December... ____ ..

Total.. 

 Al

........ 3.3

 - 3.1

....... 3.4

.... .... 5.5

....... 1.5

1962

A2

3.8

4.6

3.7

2.2

1.9

A3

3.7

4.2

4.3

2.6

2.4

Al

4 0

2 1

5.9

10 7

11.8

8

O

4 fi

4.3

3.0

2.4

£3.8

1963

A9

5.0

4.0

8 n

10.6

8.2

7.6

5.5

3.4

2.1

1.4

50.8

A3

5.2

2.3

5.2

fi 9

5.2

6.2

9 8

2.0

O n

1.6

33.5

Al

5.8

1.6

.4

1.5

3.5

6.6

7.1

7.0

6.4

3.7

2.5

1.3

.8

49 4

1964

A9

5.3

1.0

1.0

9 7

4 9

3.6

4 9

3.8

9 8

2.0

1.4

.5

95S 7

A3

5.8

0.6

.2

.8

2.0

.3.7

4.6

5.2

3.9

3.3

2.3

1.7

.2

28.5

Al

5.5

0.5

.8

1.8

2 0

6.8

4.1

6.2

6.5

4.0

2.4

1.0 -.6

36.5

1965

A9

3.5

2.5

1.8

2.0

1

C

5.1

4.0

6.4

6.1

3.8

2.5

1.4 -1.2

36.2

A3

3.5

2.8 .

1.8

2.6

1.6

4 8

4 0

7.0

5.3

5.9

2.7

1 0

-.4

41.0

Al

5.6

-0.2

1 8

2.9

4.2

5.7

8.9

6.4

6.0

3.4

3.2

2.4

44 7

1966

A9

3.5

0.3

1.2

3.1

5.5

6.2

7.0

6.7

4.7

2.4

2.3

.1.8

41.2

A3

5.5

0.3

2.1

2.3

7.0

110.7

115.5

113.8

6.2

4.5

3.7

2.7

168.8

i Records not representative because of growth of young arrowweed in tank.

Fourwing saltbush, which is smaller and slower 

growing than quailbrush, commonly grows in separate 

rounded clumps with bare areas between. Tank A3 and 

the area surrounding it were planted with fourwing 

saltbush in 1961. Because of poor survival, additional 

planting was necessary in 1962 and 1963. Full area! 

coverage was not achieved during the period of operation. Photographs in figure 6 show the vegetation in 

tank A3 in two stages of growth and a natural stand 

of fourwing saltbush on the Yuma Mesa during an 

infrequent seeding period.

The water table in A3 was held at a depth of 3.7 

feet during 1962, then lowered to 5.2 and 5.8 feet during 1963 and 1964, respectively. In 1965, it was again 

raised to 3.5 feet below the land surface to test the 

effect of depth of the water table on water use. The 

vegetation was noticeably less vigorous during 1965 

than in 1964, but the water use was greater. Raising 

the water levels probably was not the only cause for 

the poor condition of the vegetation in the tank, as 

similar vegetation outside the tank also lost vigor during 1965. In January 1966, the tank was leached and 10 

pounds of nitrogen fertilizer was added to the feed 

water; the water level was held at 5.5 feet below the 

land surface. The vegetation showed renewed vigor 

during the year and made good growth, while similar 

vegetation adjacent to the tank showed little change 

from 1965.

Monthly water use by the fourwing saltbush in tank 

A3 for the period of record is shown in table 4 and 

plotted in figure 4. The high rate of water use during 

May to August 1966 was affected by an infestation of 

young volunteer arrowweed and baccharis, which was 

removed on August 20; therefore, the water use rates 

during these months are not representative of the fourwing saltbush alone. Comparison of the vigor and 

growth of the saltbush during 1965 and 1966 suggest 

that the rate of water use should be higher during 1966

than during 1965, but not so high as indicated in the 

table.

BABE SOIL

Evaporation from bare soil was measured in three 

tanks; they have the same features as the tanks previously described. Water was added from the bottom 

through feed pipes, and the surface was wet only by 

upward moving moisture except for rare occurrences of 

precipitation. The surface of the tanks was approximately level with the adjacent land surface, and an 

area at least 30 feet wide surrounding the tanks was 

maintained free of vegetation.

The soil in the tanks was fairly well mixed as a result of the method of construction. Generally, it consisted of sand and silt with a minor percentage of clay. 

The results of sieve analyses, as shown in table 5, indicate some differences in the soil of the three tanks. Tank 

BSl has the greatest percentage of clay and silt, and 

BS3 has the greatest percentage of sand.

TABLE 5. Sieve analyses of soil in bare-soil tanks at 

Imperial Camp

Type of soil

Particle 

size, in 

mm

_.__ 0.010

.020 

.037 

.074 

.___ . 140

.590

Cumulative percent, by 

weight, of particles smaller 

than size indicated

BSl

9 

14 

26 

62 

99 

100

BS2

7 

8 

16 

49 

97 

100

BS3

4 

6 

11 

37 

95 

100

Water levels in the bare-soil tanks were maintained 

at depths of 3.0 feet below the land surface in 1962. 

In 1963 and 1964 the level in BSl was held at 2.0 feet, 

and in BS3 it was held at 4.0 feet to determine the effect 

of depth on evaporation rates. Prior to August 1963, 

the water levels were maintained within a narrow range

287-538 O 6S
F10 WATER RESOURCES OF LOWER COLORADO RIVER SALTON SEA AREA

A

B

FIGURE 6. Fourwing saltbush (Atriplea; caneacena), in evapotranspiration tank at Imperial Camp, Calif. A. View of evapotranspiration 

tank A3 from northwest, July 12, 1962. B. Similar view of A3, Oct. 25, 

1963. Vegetation in seed following good growth. C. Native stand on 

mesa near Yuma following good growing season, Oct. 25, 1963. The. 

water table was about 50 feet below land surface.

by an automatic water feed, but after that date, the 

water levels fluctuated greatly because relatively larger 

quantities of water had to be added to the tanks by hand 

two or three times a week. As the depth to water was 

measured each time before water was added, the average water level after August 1963 was higher than indicated by the measurements. This effect was most pronounced for tank BS1, which had the highest water 

level and water use.

The surface of the soil in tank BS1 appeared moist 

except during periods of greatest evaporation. A crust 

of alkali that formed during 1963 was scraped off 

with a square-point shovel during the spring of 1964, 

but it re-formed within a few weeks. Pools of water 

sometimes formed briefly on the surface of the tank 

shortly after rapid manual filling; these were probably attributable to temporary hydrostatic pressure, 

which caused the water to move upward through the 

more permeable zones.

Some deposition of salts was apparent on the surface of tank BS2, but the soil surface of tank BS3 

differed little in appearance from that of the surrounding area. Photographs shown in figure 7 depict the difference in surface conditions of the three tanks.

Precipitation has not been included in the data shown 

in table 6, because the purpose of the study was to 

determine the net draft on ground water by evaporation 

from bare soil. Precipitation during the months of 

August, September, and October 1963 and August 1964, 

as shown in table 12, was sufficient to affect the draft on 

ground water significantly during those months. In 

some other months, the rainfall was greater than the 

evaporation; this resulted in a net gain of water for 

those months. Beginning with April 1963, records 

of evaporation were adjusted for changes in soil moisture during the month. These changes were small, generally ranging from 0.1 to 0.3 inch. They hardly exceeded the range of probable error of determination.
CONSUMPTIVE USE OF WATER BY PHREATOPHYTES AND HYDROPHYTES NEAR YUMA, ARIZONA Fll

t^v*

 SI

D

FIGURE 7. Surface of bare-soil evaporation tanks, June 26, 1964, Imperial Camp, Calif. A. Detail of soil in tank BS1, right side of photograph 

Ground water about 2.0 feet below land surface. Note wet surface and salt crust, in contrast with surrounding soil. B. Tank BS2, right 

side of photograph. Ground water 3.0 feet below surface. Soil in tank usually appeared dry, but salt deposits are evident. C. Tank BS3, 

on right. No difference in soil appearance inside or outside the tank. Soil surface always appeared dry. Depth to water 4.0 ft. D. General view 

of tank BS2.

Deviation from any apparent seasonal trend of evaporation from tank BS3, and to a less extent from BS2, may 

be, in part, attributed to error inherent in taking the 

soil-moisture measurements.

Annual evaporation from the bare-soil tanks at watertable depths of 2 and 3 feet, estimated from data in 

table 6 to be 20.0 and 6.6 inches respectively, are within 

the range of previous experimental results. At a watertable depth of 4: feet, however, the indicated evaporation of 3.2 inches is less than that found in some other 

experiments.

Research hydrologist T. E. A. van Hylckama (written commun., 1965), U.S. Geological Survey, reports 

that near Buckeye, Ariz., net yearly evaporation from a 

silty clay soil was about 17 inches from depths of 4 feet 

in a 100-square-f oot tank surrounded by vegetation and
F12 WATEiR RESOURCES OF LOWER COLORADO RIVEK SALTON SEA AREA

TABLE 6. Monthly evaporation of ground water from bare-soil tanks, excluding 

precipitation, in inches, at Imperial Camp

[Negative values indicate that gain in soil moisture is greater than feed water added]

1962 1963 1064

Tank

Nominal depth to water- -feetJanuary -. _ __ .. ...

February _ ......

March..- _ ......

April.......... ...... ..

May..- - __ - .... ...

June ___ . ...

July... .......... .

August __ - .....

September ____________ 

October -- _ - .. _ _

November. _ .

December.. __ ...

Total........... .

2.7

0.80

Oft

OQ

.65 

59

Afl

.28

4 v&

3.0

CO

fii

Cf\

.58 

.51

QQ

.27

A QQ

2.6

91 1 03

1.05

.76 

.68

.51

.42

5.95

1.9

I

Ofi

1 Aft

- 1.M5

1 46

1.27

1.60

I

fil

1 QA

.78

11 79

3.0

O

Q1?

QO

AQ

.55

70

CO

1.45

i-.ll 

1.42

07

.32

C CO

3.5

0.15

.10

.11

1Q

Aft

.24

1.18

10 

»-.20

.42

.30 .

O AQ

2.1

1 04

94

I

oq

1.57

2.74

2.05 2 01

21.74

3.0

AS

44

».07 

.56

97

7.17

J3B 6

4.0

0.17

.17

 £o

£1

»,27 

1.01

1 Affected by precipitation.

about 23 inches from a similar tank in a cleared area. 

Precipitation at Buckeye is only slightly more than at 

Yuma. At Glenbar, Ariz., the U.S. Geological Survey 

measured evaporation from clay loam soil in metal tanks 

4 feet in diameter in 1943^4. The records cover about 

a year but are incomplete. They showed evaporation of 

11 inches for a depth to water of 3.9 feet and about 25 

inches for a depth of water of 2.0 feet. Young (1933) 

found that for fine sandy loam soil at Santa Ana, Calif., 

the evaporation from tanks similar to those used at 

Glenbar, Ariz., was 18 inches for a depth to water of 

2.0 feet in disturbed soil, and .5 inches for a depth to 

water of 4 feet in undisturbed soil. The Santa Ana 

tanks were shielded from rainfall.

In Escalante Valley, Utah, White (1932) measured 

the evaporation from a clay loam soil in metal tanks 

during 1926 and 1927 for periods approximating the 

growing season, April to October. For soil tanks having a water-table depth of 5 feet, evaporation from May 

to October averaged 3.7 inches; for a depth of 3.3 feet, 

the evaporation from May to October was 6.3 inches 

(partly estimated); and for a depth of 1.1 feet, from 

June to October, 10.1 inches.

In all previous experiments, except those at Santa 

Ana, Calif., the tanks received natural rainfall that was 

not included as evaporated water. These records, therefore, represent evaporation of ground water from the 

soil surfaces. Data on evaporation from soil surfaces 

referred to above are plotted in figure 8.

The type of soil and degree of compaction probably 

have an important effect upon rates of evaporation. 

Certainly when the capillary fringe reaches the surface 

of the soil, the transfer of vapor to the atmosphere is 

expedited and evaporation rates are substantially 

greater than if the upper limit of the capillary fringe is 

a foot or more below the surface. The tanks near Yuma

and those near Buckeye were not compacted after filling except by rare foot traffic, by adding water through 

the feed pipes, and by rainfall. The sandy soil on the 

surface of tanks BS2 and BS3 remained loose throughout the tests; however, by 1962 the soil in the tanks 

was believed to be comparable to that of similar soil 

in the natural flood plain.

 x

o

I 2

10 15 20 

ANNUAL EVAPORATION IN INCHES

EXPLANATION

O Yuma, Arizona 

© Buckeye, Arizona 

+ Glenbar, Arizona 

 Santa Ana, California 

X Escalante Valley, Utah

Silty-loam soil 

Silty-clay soil 

Clay-loam soil 

Fine sandy-loam soil 

Clay-loam soil

FIGURE 8. Relations of annual evaporation of ground water from 

bare soil to depth of water table below land surface, Ariz., Calif., 

Utah.
CONSUMPTIVE USE OF WATER BY PHREATOPHYTES AND HYDROPHYTES NEAR YUMA, ARIZONA F13

BERMUDA GRASS

The three large tanks previously used for bare-soil 

evaporation studies were seeded to bermuda grass (Cynodon dactylon) during the early spring of 1965. Sprinkling was necessary until early May when the grass 

roots had developed sufficiently to maintain growth by 

subirrigation. The depth to the water table in all tanks 

was held at about 3.5 feet during 1965 and 1966, and 

throughout this time the grass did not seem to suffer 

from lack of water. A strip 20 feet wide surrounding 

these tanks had been maintained bare for the soil evaporation studies and was kept bare for the bermuda 

grass studies.

During the 1965 season, growth was only fair: areal 

density was estimated to be 95 percent, and the average 

height was about 4 inches. The amount of foliage represented probably less than 50 percent of the foliage 

grown commercially for seed in the Yuma area. Two 

light applications of nitrogen fertilizer proved to be 

inadequate to promote good growth. The tanks were 

leached during January 1966, and heavy applications of 

nitrogen fertilizer (commercial urea) were applied to 

each tank as follows: 25 pounds on March 14, and 10 

pounds on April 4, 22, May 23, and July 11. The bermuda grass responded quickly and grew vigorously 

during the year. The areal density in tank BGl.was 

about 90 percent, and the other two tanks were completely covered. The grass reached a height of about 

12-15 inches in June and remained at this height until 

November. A compact mat of vegetation about 4 inches 

deep was formed by the stems as they reclined while 

continuing to grow in length during the season. The 

grass in tank BG2, harvested on November 9, 1966, 

produced a dry weight of hay equivalent to 10.0 tons per 

acre.

The monthly water use, shown in table 7, was calculated on the basis of the net area enclosed by the 

redwood frame placed just inside the plastic tank liner 

to protect the liner from damage by roots. During 1966 

the average water use by the three tanks was about 68.5 

inches during the growing season, April to November. 

This figure does not include 2.94 inches of precipitation.

RELATION BETWEEN VOLUME OF VEGETATION AND 

WATER USE

The records of vegetation volume and water use of 

the tanks at Imperial Camp indicate, in general, a decrease in rate of water use per unit volume during the 

years 1963-66, as shown in figure 9. In this graph, the 

volume of arrowweed for 1963 used in computing the 

plotting position was the average equivalent volume for

TABLE 7. Monthly water use by bermuda grass in tanks, excluding 

rainfall, in inches, Imperial Camp

[Negative values indicate that gain in soil moisture is greater than feed water added]

1966 1966

Tank................ BQ 1 BQ 2 BQ 3 BQ 1 BQ 2 BQ 3

January.________________________________________________

February____________________________ 1.3 0.7 0.1

March_________________________________ 2.0 2.7 2.6

April__________________________________ 5.3 6.4 7.7

May__________________________________ 7.5 11.0 9.2

June--____--_. 6.0 6.5 6.4 10.2 11.1 11.0

July -__--_- 6.1 8.9 9.0 13.4 14.5 14.8

August-.___-__ 5.6 8.4 7.2 12.1 12.3, 10.6

September-_-__ 4.7 5.3 6.6 8.0 8.0 8.2

October.______ 3.8 4.2 4.0 3.0 4.1 J 2. 0

November--.-. 3 0 3 0. 6 3 0. 8 2. 4 2 1. 9 2.5

December. __ «-0. 5 «-0. 8 »-1. 0 .9 1.6 .3

Total.. __ 25.7 33.1 33.0 66.2 74.3 69.0

1 Estimated, tank flooded.

2 Grass out Nov. 10.

3 Affected by precipitation.

the two surveys given in table 1, July 11 and October 8. 

The volume of Atriplex (fourwing saltbush and quailbrush) was calculated in a similar manner from table 

3 by using the total measured volumes. Monthly water 

use is 'given in tables 2 and 4. The short periods of missing record were estimated so that yearly totals could 

be calculated.

The relation between the volume of vegetation and 

the consumptive use (see fig. 9) is influenced by the 

methods of measuring volume, which were too crude to 

provide an accurate measure of actual transpiring 

foliage or to define changes within the growing season. 

The amount of nontranspiring vegetation included in 

the volumes used to define the relations tended to increase with time and tended to reduce the computed 

unit rate of water use. As previously mentioned, during 

and after 1964, the average height of the quailbrush in 

tanks Al and A2 was 6-7 feet, but only the upper 2 to 

3 feet was actively transpiring. If the estimated volume 

of transpiring foliage is used to compute a rate of consumptive use per unit volume, there is no reduction 

with time.

The unit rate of water use by arrowweed is also influenced by nontranspiring foliage, although to a lesser 

extent than quailbrush. During the survey of vegetation 

volume on September 15, 1966, the lower margin of the 

transpiring foliage was estimated to be about 3.3 feet 

above ground level (table 1). Even during the 2 previous years, the amount of transpiring vegetation near 

the ground decreased. The downward trend of the curve 

for arrowweed in figure 9 is undoubtedly influenced by 

the relative increase in the nontranspiring volume, but 

by an undertermined amount.
F14 WATER RESOURCES OF LOWER COLORADO RIVER SALTON SEA AREA

30

cr ^

UJ K 

Q.JC

(/) LU

LU O

I LU

O > 20

LU uj

10

(-i/

x^Arrowweed

V,

Fourwing saltbush

- a.

Arrowweed

1963 1964 1965 1966

YEAR

FIGURE 9. Yearly water use of vegetation in tanks at Imperial 

Camp, Calif., 1963-66.

EFFECTS OF SALINITY

The Imperial Camp area is fairly typical of much of 

the phreatophyte-infested flood plain of the lower 

Colorado River. Although the bare soil in some small 

tracts was very saline, the soil at the tank sites was less 

saline and seemed to be representative of most of the 

soils in which the native arrowweed was growing. Because most of the native phreatophytes are relatively 

tolerant of salts, the soil excavated for construction of 

the tanks was considered satisfactory for growing the 

plant species to be studied. Any natural stratification of 

salts that may have existed in the undisturbed soils was 

destroyed when the soil was disturbed by the excavating 

and the refilling of the tanks. Leaching was necessary 

to establish a good stand of vegetation in the tanks. 

These experiments were not designed to determine the 

effects of salinity on water use, but the authors believe 

the effects may be significant.

The feed water was obtained from a deep well that 

supplied Imperial Camp and was similar in quality to 

Colorado River water. Chemical analyses of samples 

taken from the feed pipe and from Colorado River on 

April 21, 1961, showed the following results:

Specific conductance at 25°C

micro mhos .

Ca + Mg ___________ _ ppm_

4_ __-__-_---__--___ _ppm_

CL_ ________ _---_-____

Feed 

water

1, 160

115

174

297

108

Colorado 

River

1, 190

126

172

307

111

Soil samples were collected in 1963 and 1966 to determine the concentration of salts in the soil of the tanks 

and in the areas of native vegetation nearby. Figure 10 

shows the standard specific conductance (electrical conductivity of water at 25°C) of water extracted from

SPECIFIC CONDUCTANCE, IN MICROMHOS AT 25° C

FIGURE 10. Specific conductance of water extracted from saturated 

soil samples at various depths at Imperial Camp, Calif., January 

1966.

saturated soil samples taken at various depths in January 1966. The specific conductance is related to the 

salinity of the water sample, and the dissolved solids in 

parts per million may be obtained by multiplying the 

specific conductance in micromhos by a factor of 0.6. 

Samples designated AWN1 and AWN2 in figure 10 were 

obtained from native arrowweed areas near the tanks. 

Other samples were from arrowweed and atriplex tanks 

that were leached during January to February 1963 and 

from bermuda grass tanks that were leached in January 

1965.
CONSUMPTIVE USE OF WATER BY PHREATOPHYTES AND HYDROPHYTES NEAR YUMA, ARIZONA F15

In general, the highest concentration of salts in the 

soil occurs in a zone just above the capillary fringe; this 

zone also seems to be the zone of greatest concentration 

of roots. Roots of arrowweed, for example, were found 

most frequently in soil samples taken at depths of about 

3 feet, both in the tanks and outside; the zone of highest 

salinity was also at this depth. Roots of Atriplex were 

noticeably shallower. The distribution of the roots of 

bermuda grass seemed to be related to the type of soil. 

For example, the roots in tank BG1 were found mostly 

in the sample taken from the top 0.5 foot, whereas in 

BG3 many roots were found in the sample taken from 

1.5 to 2.0 feet in depth. The difference in depths apparently reflects the difference in the relative amounts 

of sand and clay present in the two tanks. Rainfall during December 1965 may have leached the top few inches 

of soil in tanks AW2 and AW3, as the salinity profile 

for these tanks show lower concentrations than those 

indicated by the feed water.

Although the salinity profiles were defined by samples 

from only one site in each tank, the results are believed 

to be reasonably representative of the salinity of the 

tanks. Computations of the amount of soluble salts 

added by the feed water since the tanks were last 

leached agree approximately with the increase in total 

salts estimated from the profiles of May 1963 (not 

shown) and January 1966.

The concentration of salts in the soil in the area containing native vegetation was much greater than in 

the soil in the tanks because of the past leaching of the 

tanks. Sample AWN2 (fig. 10) had the highest salt 

concentration of all the samples. The site of this sample 

was about half a mile from the tanks in an area of 

native vegetation. The old arrowweed was about 4 feet 

high (with about 20 percent deadwood) and had slightly 

less than average vigor. Moderate deposits of salts were 

visible on the ground surface. Sample AWN1 was from 

an area surrounding a tank where the vegetation had 

been cleared and the soil surface disturbed during 

preparation of the tanks, and the vegetation had been 

restored by transplanting and natural regrowtli. No 

surface deposits of salts were apparent here. Arrowweed at this site was 9-10 feet in height, vigorous and 

leafy, and without deadwood. The ground-water level 

at site AWN1 was about 5 feet below land surface, and 

at AWN2, about 6 feet.

Considering the vigor of the arrowweed near the 

site of sample AWN1, there is no reason to believe 

that the accumulation of salts in the arrowweed tanks 

limited either the growth or the water use during the 

period 1963-65. AtripUx seems to be at least as tolerant 

of salinity as arrowweed, and the concentration of salts

in the tanks seems to have been well within the tolerance 

range.

MITTRY LAKE SITE

A group of evapotranspiration tanks and meteorological instruments were operated during the period July 

1961 to December 31, 1964, at Mittry Lake, at a site 

about 3 miles southeast of the Imperial Camp site 

(fig. 1). Cattail (Typha latifolia) and carrizo (Phragmites communis) were planted each in three tanks. The 

tanks were 10 by 10 by 4 feet and similar in design to 

those at the Imperial Camp site.

The evapotranspiration tanks at Mittry Lake were 

dug in the swampy margin of the lake and were surrounded by cattail growing in shallow standing water. 

Toward the shore the native cattail became less dense 

and less vigorous, giving way to saltcedar within 150 

and 200 feet from the water. Because cattail grows best 

in shallow water, the water level in the tanks was maintained at a depth of about 0.3 of a foot.

Water was pumped from Mittry Lake and applied 

directly to the surface of the tanks. The soil was predominately clay and silt deposited by the river after 

the construction of Laguna Dam in 1907. The carrizo 

did not thrive in the tanks; so this species was abandoned, and one of the tanks was converted to the measurement of evaporation from open water.

CATTAIL

Cattail stalks grow to maturity and die each season. 

In the Yuma area, growth begins in March and ends in 

July; the foliage begins to die in October and usually is 

dry by December. The cattail transplanted in the tanks 

in June 1961 survived but grew very little during the 

remainder of the year. During 1962 and the following 

years, the plants grew normally and attained an average 

height of 6-7 feet each year. The cattail in the tanks 

blended well with that of the surrounding area and 

attained comparable size and vigor, as can be seen in 

the photographs (fig. 11).

Volume of cattail was calculated from measurements 

of canopy area and average height. The cattail were 

planted in the tanks in the same pattern that the 

native cattails grow with about the same amount of 

space between each plant. The density varied little 

during the 3 years of growth. The height, and consequently the volume, tended to increase as shown in 

table 8.

Water in the tanks was maintained 0.2-0.3 foot above 

mean land surface, by reference to a fixed point. To prevent the concentration of dissolved salts, the water was 

changed at least once a week by pumping it through the 

reversible water-feed system. When the cattail top
F16 WATElR RESOURCES OF LOWER COLORADO RIVER SALTON SEA AREA

FIGDRE 11. Mittry Lake, Ariz., evapotranspiration tanks showing cattail. A. General view of area, Oct. 12, 1963. Open-water evaporation 

tank to right and beyond instrument shelter. U.S. Weather Bureau 

Class A pan to left. Man standing at cattail Tank Cl beyond shelter. 

B. Tank Cl lies between rod and post to right of man. There is a plank 

walkway over standing water at left. Nov. 5, 1964. C. View showing 

detail of cattail in tank Cl and feed pipes, Apr. 6, 1964. Old vegetation had been removed in December.

growth was completely dead, about January 1 of each 

year, the tanks and about a 10-foot-wide area surrounding them were cleared by cutting the stalks just above 

water level. This was primarily a fire protection measure; the area nearby burned twice during the 3 years of 

operation.

TABLE 8. Volume, in cubic feet, of cattail in evapotranspiration tanks at Mittry Lake, Ariz.

Date of survey

Tank

Cl C2 C3

Average 

volume

Dec. 28, 1962._____ 524 569 558 550

July 12, 1963_-.-_- 618 600 618 612

Oct. 4, 1963_-------- 587 600 605 597

Sept. 24, 1964_______ 612 676 800 696

Consumptive use from tank Cl showed 110 progressive 

increase or decrease during the 3 years, as indicated by 

table 9 and figure 12. Unlike the data collected at the 

Imperial Camp site, the water use data for this site included precipitation in addition to the water supplied 

by pumping. As the tank surfaces were covered with 

water at all times, precipitation contributed directly to 

the water supply.

J FMAMJ JASONDJ FMAMJ JASONDJFMAMJ JASOND

1962 1963 1964

FIGURE 12. Monthly water use and volume of cattail in tanks at 

Mittry Lake, Ariz. Dashed lines indicate approximate changes in 

volume of vegetation in the tanks. The vegetation was cut and 

removed during January of each year.
CONSUMPTIVE USE OF WATER BY PHREATOPHYTES AND HYDROPHYTES NEAR YUMA, ARIZONA F17

The color of the vegetation was about the same each 

year. The vegetation in tank C2 noticeably improved in 

vigor during 1964 compared with previous years, and 

the increased water use by this tank during that year is

associated with this change. The improved vigor is believed to have resulted from the greater depth of water 

maintained in this tank during 1964, when the operating water level was raised 0.12 of a foot.

TABLE 9. Monthly water use, including rainfall, in inches, by cattail in tanks,

Mittry Lake

Tank __ . .. . .. ... . .. .

January . __ ________ .

February ........................

March.. . ___________ ..

April. ..........................

May.. ________ . .. ...

June. __ . ...................

July..... ...... . _.._....._

August __ .. .................

September _______ ___ .. 

October... ..................

November ___ ____ ....

December. ....................

Total. - - ..

Cl

7.3

1*> *>

15.0

20.5

16.4

12.1 

8.8

5.3

2.5

100.1

1962

C2

6.3

10.6

13.1

16.2

13.1

9.8

7.5

4.4

2 A

83.4

03

6.6

1O ft

14.6

16.6

14.4

10.7 

8.0

4.2

o o

89.3

Cl

1.6

3.0

5.7

10.3

16.9 170

17.6

12.6

11.2 

5.6

2 7

1

0

105.7

1963

C2

1.6

3.1

5.5

9.1

14.0

14.5

14.2

10.3

9.2 

4,3

1.8

1.0

88.6

f-1 n

1.5

2.9

5.8

10.2

15.9

16.4

........

52.7

Cl

1.4

4.7

5.8

11.3

16.7

19.0

17.4

11.7

8.1 

4.6

2.4

1.3

ml i

1964

C2

1.2 .

4.4 .

fi 0

12.3 .

16.7

1Q (\

17 Q

12.1

9.3

7.2

5.0

3.2

114.5

C3

17.0

25.0

9O 1

91 8

18.5 

13.3

7.6

2

C

134.9

Kecords from tank C3 are incomplete during 1963 

and 1964 because of recurring leakage. After the tank 

was repaired in 1964, the depth of water in the tank was 

arbitrarily increased by about 0.25 of a foot, thereby 

raising the water level in this tank to an appreciably 

higher level than in the other two tanks. This condition 

apparently promoted the growth of the cattail, because 

at the end of the 1964 season, the plants were 2-3 feet 

higher than the cattail in the surrounding area and in 

the other two tanks. There is a possibility that not all 

the leaks in the tank were repaired, and if so, this would 

have affected the apparent rate of water use; however, 

no leakage was observed.

EFFECTS OF SALINITY

Cattail and other hydrophytes are affected by the concentration of salts dissolved in the water, but the concentration beyond which evapotranspiration and growth 

would be retarded was not determined by the tank experiments. Precautions were taken to assure that the 

water remained sufficiently fresh to insure good growth 

by using the water from Mittry Lake, which was supporting a good growth of cattails, and by frequently 

flushing the tanks. Tests of the water in Mittry Lake 

before construction showed an increase in saline concentration in a shoreward direction; the specific conductance was 5,000 micromhos for the open water at the 

margin of the vegetation in the lake and was 16,000 

micromhos for the water about 2 inches deep and 200 

feet from the open water. The height of the cattail 

decreased shoreward, but this may be attributable to the 

decreasing depth of water and to the occasional drying 

out of the lake bottom at low lake levels, as well as to 

the increased concentration of salts.

Analyses of sample water taken from the feed pipe 

and from the tanks during April 1962 indicate the quality of the water supply and the buildup of salts in the 

tanks. The water was changed in the tanks on March 30, 

1962, and tests were made on April 4 and 12. The results 

were as follows:

Source

Specific conDate ductance, in Concentration of 

[April 19621 micromhos, at chloride (ppm) 

25° C.

Feedpipe. _________

Tank Cl..___. ____..

Tank C2.._. ........

Tank C3... .........

.... 4

_... 4

12

.... 4

12

.... 4

12

5,000

9,190

12,500 ...

9,040

12,200 ...

7,930

10,800 -._

802

2,120

2,020

1,740

Barely during the period of operation did the specific 

conductance exceed 10,000 micromhos, and the vegetation in the tanks at all times seemed to be about as 

healthy as the surrounding native vegetation.

FLUCTUATIONS OF THE WATER TABLE

A continuous record of water-level fluctuations was 

obtained for the years 1962-65 at a site on the flood 

plain in a stand of arrowweed. The well site was at Imperial Camp, about one-fourth of a mile northeast of the 

transpiration tanks and about 1,500 feet from the river; 

it was in a fairly uniform stand of arrowweed that had 

slightly less than average density.

The common pattern of diurnal fluctuations occurred 

in the well (see figs. 13, 14) at all times except during 

infrequent periods of extremely low temperature or of 

precipitation. According to White (1932, p. 59-61), the 

fluctuations result from diurnal variations in transpiration rates of the vegetation. Irregularities in the usual 

normal diurnal cycles of temperature and humidity are 

reflected in the shape of the diurnal fluctuation of water
F18 WATER RESOURCES OF LOWER COLORADO RIVER SALTON SEA AREA

21 

MARCH 1963

FIGURE 13. Diurnal fluctuations In ground-water levels, air temperature, and relative humidity, Imperial Camp, Calif., March, 1963.

levels. For example, the rapid drop in temperature and 

associated rise in relative humidity during late afternoon of September 14 (fig. 14) caused the water level 

in the well to rise faster than usual; these changes illustrate the close correlation of these variables.

As expected, the amplitude of the fluctuations was 

greater in summer than in winter, and the changes from 

rising to falling stages were closely related to air temperature and humidity. The water levels reacted quickly 

to the increased transpiration at sunrise during the 

summer months; the reversal from rising stage to falling 

stage was observed to occur less than 15 minutes after 

the first rays of sun reached the area.

The depth of the water table in the well was related 

to the amplitude of the water-level fluctuations, as 

shown in figure 15. The seasonal pattern of water levels 

in the well is the result of seasonal variations in water 

use by the vegetation and of the water level in the 

Colorado River. The amplitude of the diurnal fluctuations of water levels roughly correlates with the daily 

water use rate, and thus the diurnal fluctuations create 

a seasonal pattern similar to that of the water use rate 

during the years 1962-64. A new channel for the river 

was dredged nearer the well in 1965, and the river level 

dropped several feet, with a corresponding drop of more 

than 3 feet in the well. Apparently the lowering of the 

ground-water levels greatly reduced the withdrawal 

of ground water by arrowweed, as the amplitude of the

5.8

cc

Z D in s'i

LU < 

_l _l

* 5

6.0

LU

m 6.2

120

80

50

12 13 14 

SEPTEMBER 1963

15

FIGURE 14. Diurnal fluctuations in ground-water levels, air temperature, and relative humidity, Imperial Camp, Calif., September 1963.

diurnal fluctuations dropped drastically in June and 

July 1965 and the fluctuations stopped entirely in September when the water levels were more than 9 feet 

below land surface. It is presumed that at 9 feet, the 

water level was below the reach of the arrowweed roots 

at this location. Diurnal fluctuations resumed in November when water levels rose to 8 feet below the land surface.

The difference in phase of the seasonal pattern of 

depth of the water table and amplitude of diurnal 

fluctuations, shown in figure 15, cannot be readily explained. Normally, the greatest amplitude of fluctuations and the lowest ground-water levels would be expected to occur simultaneously. Note, however, that the 

lowest water levels occur in late July or early August, 

whereas the greatest amplitude of daily fluctuations 

occurs in September and October. During September 

and October, when nighttime relative humidity is at its 

highest, it is possible that transpiration is stopped for 

several hours during the night because a heavy dew 

forms on the vegetation; for this reason, the recovery of 

drawdown may be greater during these 2 months than 

it is during the drier months.
CONSUMPTIVE USE OF WATER BY PHREATOPHYTES AND HYDROPHYTES NEAR YUMA, ARIZONA F19

J FMAMJ JASONDJ FMAMJJASONDJFMAMJJ ASONDJFMAMJJASOND 

1962 1963 1964 1965

FIGURE 15. Depth of water below land surface and amplitude of diurnal fluctuations in an area of arrowweed near Imperial

Camp, Calif.

Figure 16 shows differences in phase during 1964 of 

several hydrologic variables, which are reduced to common units, as follows: Amplitude of fluctuations, water 

use by arrowweed in the tanks, evaporation from a U.S. 

Weather Bureau Class A pan, and solar radiation. 

Relatively, pan evaporation and solar radiation accelerate first, they lead the other variables by 2 or 3 months 

from January through April and peak together in June. 

Depth to water and evapotranspiration by arrowweed 

in the tanks are about the same relative magnitude in 

most months and both peak in July, a month later than 

evaporation and radiation. This lag of evapotranspiration by about a month might be expected, owing to 

storage of heat in the soil. The amplitude of water-level 

fluctuations begins to lag after all the other variables 

in June and peaks last of all in October, 2 to 3 months 

after the peak of evapotranspiration in the tanks. This 

lag was repeated during each of the 3 years of study, 

1962-64 (fig. 17).

METEOROLOGICAL DATA

Transposition of water-use data from one area to 

another requires an adequate understanding of the environmental variables as well as of the characteristics 

of the plant species. Such understanding is still incomplete, especially for the flood plain of a river in a climate as arid as that of the area along the lower Colorado River. In the present study, consideration of 

environmental factors was limited principally to assembling and to analyzing conventional meteorological 

records.

Meteorological data were collected at Mittry Lake 

during 1963-64 and at Imperial Camp during 1963-66. 

Equipment at each site included a standard "Class A" 

evaporation pan with associated anemometer and maximum and minimum thermometers (in the water), a 

manual rain gage, and a hygrothermograph. At Mittry 

Lake, water-surface evaporation was measured in a 

special sunken ground pan that was 10 by 10 feet square 

and 1 foot deep. Both the ground pan and the Class A 

pan were at the edge of Mittry Lake. When the lake was 

at high levels, the pans were partly surrounded by 

water and cattail grew shoreward of the pans. When the 

lake was at low levels, generally in mid-summer, the 

shoreline was 10-15 feet from the pans, but the dry 

cattail shoreward of the pans still partly shielded the 

pans from winds overhead.

Other meteorological observations were made during 

the period of study by the U.S. Army at Yuma Proving 

Grounds about 3 miles east of Imperial Camp, by the 

U.S. Weather Bureau at Yuma International Airport, 

and by the University of Arizona Extension Service
F20 WATER RESOURCES OF LOWER COLORADO RIVER SALTON SEA AREA

at the Yuma Citrus Station, which is about 6 miles 

south of Yuma.

At these places significant local differences were observed in air temperature, relative humidity, wind 

movement, and evaporation. These differences reflect 

the influence of the local environment. Meteorological 

data are given for Mittry Lake in table 10, for Yuma 

Proving Ground in table 11, and for Imperial Camp 

in table 12. Records for Yuma Airport and Yuma 

Citrus Station are published in U.S. Weather Bureau 

reports and are not reproduced here.

The Yuma Airport and Yuma Proving Ground stations are in desert areas with little vegetation in the immediate vicinity, although both are within 2 miles of a 

flood plain or irrigated lands. In contrast, the meteorologic station near Imperial Camp is surrounded by vegetation and the station at Mittry Lake is adjacent to 

open water. Conditions at the later site differ from those 

at the proving ground site, for example, the average 

daily minimum temperature is nearly 10°F less at the 

lake site; the average maximum relative humidity is 

higher, owing to the same influence that results in lower 

night-time temperatures; and the average wind speed is 

less than 25 percent of that at Yuma Proving Ground, 

owing to the nearby vegetation and the unlike heights 

of the anemometers above the land surface, 0.5 meter 

at the lake and 2 meters at Yuma Proving Ground.

Pan evaporation was about 25 percent greater at Imperial Camp than at Mittry Lake. The evaporation station at Imperial Camp was in a moderately large unobstructed area adjacent to the bare soil tanks; at Mittry 

Lake the station was in a small unobstructed area nearly 

surrounded by cattail. Humidity was expected to be 

higher at the Mittry Lake station than at the Imperial 

Camp station, but the hygrothermograph records did 

not bear this out. Studies by Hughes and McDonald 

(1966) indicate that differences in wind movement and

air temperatures at the several sites account for most of 

the differences in measured evaporation.

I I I

Diurnal fluctuation s

Evapotranspiration 

by arrowweed

Shortwave 

solar radiation

J FMAMJJASOND

FIGURE 16. Relative monthly magnitude of certain hydrologic variables near Imperial Dam, Ariz. Calif.
CONSUMPTIVE USE OF WATER BY PHREATOPHYTES AND HYDROPHYTES NEAR YUMA, ARIZONA F21

Evapotranspiration 

m m

by arrowweecK \

N-1'l I I II I I I I

JFMAMJ JASONDJFMAMJJASONDJFMA M J JASONDJ FMAMJ JA SONDJ FMAM JJ ASOND 

1962 1963 1964 1965 1966

FIGURE 17. Monthly evaporation from water surface, evapotransplration by arrowweed, magnitude of diurnal fluctuations of ground-water levels, 

and evaporation-equivalent of short-wave solar radiation near Imperial Dam, Arla.-Callf.

Total.

Total.

TABLB 10. Meteorological data for Mtttry Lake site, Arizona 

[Records by U.S. Geological Survey]

Month

1963 

Jan______ __ _____

Feb... ..._._._____

Mar.. ____________

Apr. ______________

May...--. _______

June. _.____.___.__

July..... __________

Aug.. _____________

Sept..............

Oct--__._ _________

Nov _ ____________

Dec..... ..........

Precipitation 

On.)

...._____ 0

.----_... 0

____.___. 0

.-__...__ 0

---..__._ .19

---_..___ 2.21

ne,

--._.____ .12

____...__ 0

Air temperature (°F)

Max

81 

93 

95 

103 

102 

102 

90 

76 

69

Min

49 

58 

62 

72 

76 

71 

59 

47 

34

Relative humidity 

(percent)

Max

94 

92 

89 

91 

85 

85 

90 

86 

92

Min

20 

20 

24 

27 

31 

23 

28 

28 

18

Water temperature <°F)

Max

84 

93 

99 

104 

103 

104 

90 

76 

66

Min

48 

62 

65 

73 

76 

74 

64 

51 

39

Pan 

wind speed 

(mph)

1.7 

1. 1 

1.4 

1.4 

1.2 

0.8 

0.5 

0.5 

0.8

USWB 10- by 10-ft 

Class A pan tank 

evaporation evaporation 

(in.) (in.)

7.99 

10.06 

11.18 

12.99 

10.77 

9.61 ...

5.10 ...

3.58 

3.06

2.35 

3.00 

4.62 

5.79 

6.96 

7.78 

8.43 

7.31

2.20 

1.73

3.47 90 59 89 24 91 61 9.4

1.50 84.1 50.5 85.8 21.2 84.8 54.2 1.47

74.34

91.06

50.17

1964

Jan. ______________

Feb

Mar__ ____________

Apr. ______________

May. _____________

June. _.._-_.______

July

Aug ____________

Sept

Oct

Nov.. _____________

Dec __ ___________

_________ 0

--_-.____ 0

_________ 0

_________ 0

03

02

02

96

10

26

11

65

68

74

82

89

98

104

101

97

92

71

68

31

34

40

47

52

59

72

72

63

58

40

38

93

88

85

80

80

82

78

87

90

88

91

88

18

16

17

18

17

17

25

28

22

26

26

25

65

69

78

86

92

96

103

102

98

92

72

66

36

36

44

50

57

64

74

74

67

64

45

40

1.3

2.0

2. 1

2.2

1.6

1.5

1.5

1.5

1.0

0.7

1.0

1.0

3.44

5.45

6.82

9.86

10.38

12.03

12.58

10. 14

8.44

5.51

3.55

2.86

2.15

3.36

4.52

6.73

7.71

9.41

9.55

7.90

6.13

4.26

2.62

2.03

66.37
F22 WATER RESOURCES OF LOWER COLORADO RIVER SALTON SEA AREA

TABLE 11. Meteorological data for Yuma Proving Ground, Ariz. 

[Eecords by Meteorology Dept., U.S. Army, Fort Huachuca, Ariz., lat 32°50' N., long 114°24' W., 3 miles east of Imperial Camp, Calif., alt 321 ft]

Month Precipitation 

On.)

Air temperature

Max Min

Eelative humidity Wind speed Solar radiation

(percent) at 2 meters Langleys/day Total

 (mph) (Vertical Eppley) radiation

Max Min

1963

Jan....__________________________ 0.48 64 39 62 21

Feb_________--_._.__.____-_._____ .12 79 52 53 16

Mar__ ____._.____...___...______.. .22 77 49 49 13

Apr____.______.____.:______..____ .05 81 54 44 11

May........--_-__-._..-----..--. 0 95 67 35 9

June.__.___..__....__.___-_-__-.. 0 97 70 42 12

July______________._______________ 0 106 81 44 14

Aug......_.._.___.._____...._.... .13 102 81 58 25

Sept__--____---______-__-__-_.--_ 2.06 102 77 57 18

Oct______________________________ 1.17 90 66 66 24

Nov..--__-.--_._..__....---_-_-.. . 10 76 52 69 25

Dec..---......._..-___-__-__-.___ 0 70 41 46 15

Total---.----- -------.--- 4. 33_____87_____61_____52_____17

1964

Jan__.___________________________ 0 65 37 46 14

Feb___-____._______-___._.__.__.. .14 68 42 38 10

Mar_...._......__.._____..._____. .04 74 47 46 12

Apr___._.__._.__.__._._____..____ .03 82 55 42 13

May__-______._._.-_.__..-_.__-.. 0 91 63 37 11

June________..__..._.__.-__.___-. 0 99 71 34 10

July______________________________ .04 106 82 45 17

Aug______._-__._.-_________.-_-__ .07 103 81 59 23

Sept_______.______ ___ _ _ -01 98 73 52 16

Oct_.____________________-____- .12 93 67 60 21

Nov.______.______________________ .26 71 47 62 23

Dec___._-__-____.________________ .10 67 44 61 25

Total.---.-. ------------- 0. 81_____85_____59_____49_____16

1965

Jan..._.__._..__.._____.__..____. 0.66 68 45 66 25

Feb.________-___.________________ .52 71 46 54 15

Mar..._._...____._..______.___.._ .09 74 49 56 18

Apr..____________________________ 1.91 83 58 56 18

May__-____-_-_--__-__-___--____- 0 90 63 41 11

June.._____._____.._.-___._-..... 0 95 67 38 10

July....__._.__._...___.__--__..__ . 11 105 80 47 16

Aug___-__-_--__-._ __-_-_._-___ .03 104 81 56 19

Sept____---_ ---_--_-__--------- 0 96 71 47 15

Oct__-__-__-_-___---_-__----__:__ 0 95 62 35 10

Nov___-.__ ____________________ .99 76 54 37 19

Dec_--_______-_--_--___.-_--__-__ 2.11 64 45 84 42

Total..... __________________ 6.42 85 60 51 18

31

431

553

627

717

757

689

608

555

422

340

312

528

328

423

537

646

699

740

671

620

541

437

332

217

516

304

408

500

606

710

739

618

630

579

468

289

253

894

993

1,090

1,201

1,356

1,469

1,432

1,422

1,361

1,202

979

708

1, 176

1,002

1,139

1,281

1,372

1,472

1,548

1,450

1,369

1, 194

964

888

1,190

923

1,004

1, 133

1,276

1,414

1,388

1,431

1,422

1,290

805

945

858

509 1, 157
CONSUMPTIVE USE OF WATER BY PHREATOPHYTES AND HYDROPHYTES NEAR YUMA, ARIZONA F23

TABLE 12. Meteorological data for Imperial Camp, Calif. 

[Hecords of U.S. Geological Survey]

Month

1963 

Jan. ___________________________

Feb-___-_--_-------_---------_-

Mar __ ____-_-____-___-_._____

Apr____-__-_ _ -----.__ _______

May __________________________

June__ _______________________

July-----. 

Aug _______________________ -__

Sept

Oct__________ _____ _ _________

Dec___-_--_____----__-______-_-

Total-____--_--___-___-_-

1964 

Jan___ ______.___-- ______ ____

Feb-------------------__-------

Mar_____. _----___-_________--

April__-____--------______--_ __

May... _____-_-_--___-______-_

July ___ 

Aug. _______________________

Sept_.__ ___________ _ _______

Oct___.___________ _____ __ _

Nov _________________________

Dec _ _________ __ _____ __ ___

Total______ _____________

1965 

Jan

Feb__----_-__-_---______--_-___

Mar____ ______________________

Apr. ___________________________

June. __________________________

July___________________________

Aug. ___________ ___________

Sept

Oct_____ _______________________

Nov___ _______________________

Dec_____ _ _____________ _ ____

Total_____._-____________

1966 

Jan.. _________________________

Feb-_----_-_--_-_._______._____

Mar___ ____________ ___________

Apr_____ ________________ _____

June. ____----_---_______--.___

July-_______-____-_.___________

Aug .-_...-_.______________

Sept... -_---_----_____________

Oct

Nov_____ _____ ______________

Dec.. _ ______________________

Total---__---___.____-_-_

Precipitation 

On.)

_-__-. 0.

______ 0

_-_-_. 0

______ 0

_-_-__ 0

______ 2.

-.-__. 1.

.---_. 0

______ 5.

______ 0

______ 0

------ 0

_--_-- 0

------ 0

------ 1.

------ 0.

-__-_. 1.

.--_.- 0

-___-- 0

------ 0

-_-__- 0

-___.. 2.

______ 6.

__._-. 0.

-____- 0

..-_-- 0

0

.____. 3.

52 

21 

25

75 

25 

07 

16

21

07 

03

03

81

17 

27 

11

44

73 

48 

16 

51

22 

02

70

84

66

58 

32 

23

17 

32 

92 

85 

13 

12

54

Air temperature (°F)

Max

65 

81 

79 

82 

94 

96 

105 

102 

101 

90 

80 

71

87.2

67 

69 

75 

83 

92 

98 

105 

102 

100 

95 

73 

69

85.6

70 

73 

75 

83 

90 

94 

104 

104

77 

65

64 

69 

83 

88 

97 

102 

105 

106 

101 

89 

80 

70

87.9

Min

35 

45 

41 

45 

54 

58 

69 

73 

66 

56 

49 

33

51.9

30 

33 

39 

47 

52 

59 

74 

72 

61 

57 

41 

38

50.3

39 

39 

40 

48 

52 

53 

70 

71

47 .

43 _

36 .

36 _

42 _

54 .

55 

61 

72 

74 

65 

53 

43 

39

52.5 _

Relative humidity 

(percent)

Max

86 

81 

85 

80 

84 

87 

86 

89 

77 

93 

87 

79

84.5

72 

72

78 

77 

78 

81 

82 

85 

89 

85 

83 

84

80.5

79 

76 

82 

83 

79 

79 

74 

86

82 

67 

69 

84 

94 

91 

85 

84

Min

28 

23 

21 

19 

22 

24 

28 

36 

22 

29 

29 

22

25.2

22 

20 

20 

22 

20 

22 

31 

31 

25 

29 

27 

28

24.8

26 

17 

20 

21 

17 

18 

23 

26

17 

14 

21 

28 

25 

22 

26 

28

Water temperature 

(°F) 1

Max

64 

77 

81 

83 

93 

95 

99 

100 

97 

87 

76 

66

84.9

64 

66 

77 

85 

90 

93 

99 

100 

95 

89 

71 

68

83.0

65 

75 

81 

88 

91 

94 

99 

102 

96 

88 

79 

82

86.7

64 

70 

82 

89 

97 

97 

102 

104 

101 

85 

80 

69

86.8

Min

37 

48 

45 

47 

61 

62 

70 

74 

70 

63 

50 

39

55.6

34 

35 

41 

48 

54 

62 

73 

74 

65 

62 

43 

40

52.7

38 

36 

43 

53 

56 

58 

68 

71 

62 

55 

68 

41

54.1

36 

36 

45 

52 

58 

62 

74 

76 

69 

57 

48 

38

54.2

USWB 

Pan wind Class A pan 

>eed (mph) evaporation 

(in.)

2. 

2. 

2. 

2. 

2. 

2. 

2. 

2. 

1. 

1. 

2. 

2.

2.

2. 

2. 

2. 

2. 

2. 

2. 

2. 

2. 

1. 

1. 

1. 

1.

2.

1. 

2. 

2. 

2. 

2. 

2. 

2. 

1. 

2. 

1. 

1. 

1.

1.

1. 

1. 

1. 

1. 

1. 

1. 

1. 

1. 

1. 

1. 

1. 

1.

1.

3 

1 

9 

8 

4 

9 

4 

0 

05 

2 

1 

0

21

1 

9 

5 

9 

6 

7 

6 

3 

7 

2 

9 

8

27

7 

2 

0 

1 

3 

1 

0 

8 

0 

0 

0 

4

80

9

7 

4 

9 

7 

7 

5 

6 

1 

3 

1 

7

55

4.09 

5.89 

9.35 

10.58 

13.42 

14.95 

15.94 

11.95 

10.37 

6.24 

5.00 

4.71

112.87

4.59 

6.68 

7.84 

11.64 

13.47 

15.46 

15.36 

13.16 

10.94 

6.77 

4.85 

3.76

114.52

3.98 

5.70 

6.00 

9.92 

13.34 

13.60 

14.43 

13.13 

11.19 

7.83 

3.42 

3.26

106. 79

3.79 

4.50 

8.07 

10.63 

14.65 

13.68 

13.31 

14.50 

9.36 

7.41 

4.60 

4. 13

108. 63
F24 WATER RESOURCES OF LOWER COLORADO RIVER SALTON SEA AREA

REFERENCES

Blaney, H. F., and Griddle, W. D., 1962, Determining consumptive use and irrigation water requirements: Tech. Bull. 1225, 

Agric. Research Service, U.S. Dept. Agriculture, Washington, D.G., 59 p.

Gatewood, J. S., Robinson, T. W., Colby, B. R., Hem, J. D., and 

Halpenny, L. C., 1950, Use of water by bottom-land vegetation in lower Safford Valley, Ariz.: U.S. Geol. Survey 

Water-Supply Paper 1103,210 p.

Horton, J. S., Robinson, T. W., and McDonald, H. R. 1959, Guide 

for surveying phreatophyte vegetation: U.S. Dept. Agriculture Handb. 266, Washington, D.C., 37 p.

Hughes, G. H., and McDonald, C.C., 1966, Determination of 

water use by phreatophytes and hydrophytes: Jour. Hydraulics Div., Am. Soc. Civil Engineers, v. 92, HY 2, Proc. 

Paper A714, p. 71.

Robinson, T. W., 1952,' Phreatophytes and their relation to water 

in western United States: Am. Geophys. Union, Trans., v. 

33, no. 1, p. 57-61.

Robinson, T. W., 1964, Phreatophyte research in the western 

states, March 1959 to July 1964: U.S. Geol. Survey Circ. 

495, 31 p.

Robinson, T. W., and Bowser, C. W., 1959 Buckeye Project 

water use by saltcedar: U.S. Dept. of Interior, Geol. Survey and Bur. of Reclamation open-file report, 26 p.

U.S. Senate, Senate Select Committee on National Water Resources, 1960, Water resource activities in the United 

States evapotranspiration reduction: Comm. Print 21, 

42 p.

U.S. Bureau of Reclamation, 1964, Pacific Southwest water plan, 

supplemental information report on water salvage projects 

Lower Colorado River, Ariz.-Calif.: 115 p.

White, Walter N., 1932, A method of estimating ground-water 

supplies based on discharge by plants and evaporation from 

the soil: U.S. Geol. Survey Water-Supply Paper, 659-A, p. 

1-106.

Young, A. A., 1933, Investigations in the Santa Ana River valley 

and coastal plain, chap. 2 in Consumptive use of water by 

native plants growing in moist areas in southern California, 

 by H. F. Blaney, pt 1 in South coastal basin investigation 

Water losses under natural conditions from wet areas in 

southern California: Calif. Dept. Public Works, Div. Water 

Resources Bull. 44, p. 26-73.

U. S. GOVERNMENT PRINTING OFFICE : 1968 O - 287-538