£EPA
United States
Environmental Protection
Agency
Robert S Kerr Environmental Research EPA-600/2-78-160
Laboratory July 1978
Ada OK 74820
Research and Development
Implementation
of Agricultural
Salinity Control
Technology
in Grand Valley
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-78^160
July 1978
IMPLEMENTATION OP AGRICULTURAL SALINITY
CONTROL TECHNOLOGY IN GRAND VALLEY
by
Robert G. Evans
Wynn R. Walker
Gaylord V. Skogerboe
Charles W. Binder
Agricultural and Chemical Engineering Department
Colorado State University
Fort Collins/ Colorado 80523
Grant No. S-802985
Project Officer
James P. Law, Jr.
Source Management Branch
Robert S. Kerr Environmental Research Laboratory
Ada, Oklahoma 74820
ROBERT S KERR ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT-
US ENVIRONMENTAL PROTECTION AGENCY
ADA, OKLAHOMA 74820
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DISCLAIMER
This report has been reviewed by the Robert S. Kerr
Environmental Research Laboratory, U.S. Environmental Protection
Agency, and approved for publication. Approval does not signify
that the contents necessarily reflect the views and policies of
the U.S. Environmental Protection Agency, nor does mention of
trade names or commercial products constitute endorsement or
recommendation for use.
11
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FOREWORD
The Environmental Protection Agency was established to
coordinate administration of the major Federal programs designed
to protect the quality of our environment.
An important part of the Agency's effort involves the search
for information about environmental problems, management tech-
niques and new technologies through which optimum use of the
Nation's land and water resources can be assured and the threat
pollution poses to the welfare of the American people can be
minimized.
EPA's Office of Research and Development conducts this
search through a nationwide network of research facilities.
As one of these facilities, the Robert S. Kerr Environmental
Research Laboratory is responsible for the management of programs
to: (a) investigate the nature, transport, fate and management
of pollutants in groundwater; (b) develop and demonstrate methods
for treating wastewaters with soil and other natural systems;
(c) develop and demonstrate pollution control technologies for
irrigation return flows; (d) develop and demonstrate pollution
control technologies for animal production wastes; (e) develop
and demonstrate technologies to prevent, control or abate
pollution from the petroleum refining and petrochemical
industries; and (f) develop and demonstrate technologies to
manage pollution resulting from combinations of industrial
wastewaters or industrial/municipal wastewaters.
This report contributes to the knowledge essential if the
EPA is to meet the requirements of environmental laws that it
establish and enforce pollution control standards which are
reasonable, cost effective and provide adequate protection for
the American public.
William C. Galegar
Director
Robert S. Kerr Environmental
Research Laboratory
111
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PREFACE
This report is the first in a series of three reports
resulting from U.S. Environmental Protection Agency Grant No
S-802985 entitled, "Implementation of Agricultural Salinity
Control Technology in Grand Valley." This report details the
experimental design and procedures used to collect data on sev-
eral types of on-farm improvements, field drainage, canal and
lateral linings and irrigation management practices (such as
"^J^011 scheduling) as salinity control measures. The second
M K £ 1T± thls series 1S entitled, "Evaluation of Irrigation
w?Jh°fh Salinity Control in Grand Valley" and is concerned
with the evaluation of furrow, border, sprinkler, and trickle
irrigation as individual salinity control measures. The third
report of this series "Best Management Practices for Salinity
S2 r°Lln^?ra^ Vallev" develops the methodology for determining
the cost-effectiveness of individual salinity control measures
and a complete "package" of salinity control measures.
Another research project conducted in Grand Valley and
largely funded by the U.S. Environmental Protection Agency has
provided the necessary background in soil chemistry to support
the cost-effectiveness analysis in the above three reportsT This
second project, "Irrigation Practices, Return Flow Salinity, and
Crop Yields," was supported by EPA Grant No. S-800687. Two
reports resulted from this effort. The first report, "Irrigation
Practices and Return Flow Salinity," focuses upon soil chemistry
modeling and the prediction of irrigation subsurface return
flow salinity. The second report, "Potential Effects of Irri-
gation Practices on Crop Yields in Grand Valley" focuses upon
the impact of various irrigation practices in determining crop
yields, with particular emphasis on maize and wheat.
Robert G. Evans
Wynn R. Walker
Gaylord V. Skogerboe
Charles W. Binder
IV
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ABSTRACT
A summary of the results of applied research on salinity
control of irrigation return flows in the Grand Valley of
Colorado is presented for the period of 1969 to 1976. Salinity
and economic impacts are described for the Grand Valley Salinity
Control Demonstration Project which contains approximately 1,600
hectares and involves most of the local irrigation companies in
the Valley. During the eight years of studies in the project
area, 12.2 km of canals were lined, 26.54 km of laterals were
lined, 16,400 meters of drainage tile were installed, a wide
variety of on-farm improvements were constructed, and an irri-
gation scheduling program was implemented. On-farm improvements
evaluated were solid-set sprinklers, side-roll sprinklers, drip
(trickle) irrigation, furrow irrigation, and automatic cut-back
furrow irrigation. The total value of the constructed improve-
ments in the demonstration area was about $750,000. The total
improvements resulted in a salt reduction of 12,300 metric tons
per year reaching the Colorado River. This salt reduction results
in an annual benefit to downstream water users of nearly
$2,000,000. In addition, there are benefits to the local water
users with increased crop yields, and to the people of Grand
Valley in increased business.
This report was submitted in fulfillment of Grant No.
S-802985 by the Agricultural and Chemical Engineering Department
of Colorado State University under the sponsorship of the <
Robert S. Kerr Environmental Research Laboratory, U.S. Environ
mental Protection Agency. This report covers the period
February 18, 1974 to February 17, 1977.
v
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CONTENTS
Foreword
Preface
Figures
Tables
...
Abbreviations and Symbols ................ x111
Acknowledgment ..................... xv
1. Introduction ...................
2. Conclusions ................... 14
3. Recommendations ................. 1'
4. The Grand Valley ................. 19
5. Grand Valley Salinity Control Demonstration
Project ..................... 45
6. Project Initiation ................ 7^
7. Design, Construction and Operation of Improvements 82
8. Participation and Response by Irrigators and Local
Organizations ..................
9. Evaluating the Effectiveness of Lateral Subsystem
Improvements ...................
10. Local Institutional Aspects of Salinity Control . 175
...... 188
References
Bibliography
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LIST OF FIGURES
Number
Page
1 The Colorado River Basin ............... 2
2 Relative magnitude and sources of salt in the
Colorado River Basin ..........
3
3 Location of Grand Valley Salinity Control
Demonstration Project
4 Grand Valley Salinity Control Demonstration Project
Area ........................ 9
5 Location of the nine selected lateral subsystems
incorporated in the project ............ 10
6 Normal precipitation and temperature at Grand
Junction, Colorado ................. 21
7 General geologic cross-section of the Grand Valley . . 23
8 Photograph of crystaline salt lenses in Mancos
Shale in the irrigation area of the Grand Valley . . 24
9 Soils map of irrigated lands in Grand Valley ..... 25
10 Approximate areal extent of cobble aquifer in the
Grand Valley .................... 29
11 Frequency distribution of Grand Valley farm sizes . . 31
12 Frequency distribution of agricultural field sizes
in the Grand Valley ................ 32
13 Agricultural land use in the Grand Valley ...... 33
14 Graphic representation of the magnitude and
distribution of water flows in the Grand
Valley for 1968 .................. 36
15 Grand Valley Canal Distribution System ........ 38
Vlll
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16 Waterlogging and salinity problems in Grand Valley . . 46
17 Soil classification map of the Grand Valley Salinity
Control Demonstration Project 47
18 Typical geologic cross-section through the
demonstration area 48
19 Location of hydrologic measurement points in the
Grand Valley Salinity Control Demonstration
Project Area 50
20 Installation of monitoring network 51
21 Canal ponding tests by project personnel 57
22 Photographs of the canal lining program 59
23 Location and type of canal linings constructed in
the demonstration area 61
24 Seasonal distribution of salt pickup from the farms
in the test area 67
25 Announcement of grant award in Daily Sentinel .... 72
26 Data collection activities by project personnel ... 80
27 Staff gauges for 8-inch by 3-foot and a 3-inch
by 3-foot Cutthroat flumes 83
28 Cutthroat flume installation and operation 84
29 Collection of lateral design information 86
30 Map of Lateral HL C shows improvements and field ^
locations
31 Tiling of the large open drain on Lateral HL C . . . . 90
32 Map of lateral and on-farm improvements under the
HL E lateral system
33 Overhead sprinklers on Lateral HL E 93
34 Map of lateral and on-farm improvements under PD 177
lateral system
35 Construction of Lateral PD 177 98
36 Drip irrigation on Lateral PD 177 99
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37 Map of lateral and on-farm improvements under GV
92 lateral system ................. 102
38 Lateral GV 92 before and after installation of
concrete ditch .................. 103
39 Map of lateral and on-farm improvements under GV
95 lateral system ................. 104
40 Improvements on Lateral GV 95 ............ 105
41 Map of lateral and on-farm improvements under GV
160 lateral system
42 Improvements on Lateral GV 160 ........... 109
43 Improvements on Lateral MC 3 ............
44 Map of lateral and on-farm improvements under MC
3 lateral system .................
45 Map of lateral and on-farm improvements under MC
10 lateral system ................. 114
46 Improvements before and after on a section of
Lateral MC 10 ................... 115
47 Improvements on Lateral MC 10 ............ ng
48 Map of lateral and on-farm improvements under MC
30 lateral system ................. 118
49 Improvements on Lateral MC 30
50 Location of drainage installations in the Grand
Valley Salinity Control Demonstration Area .... 121
51 Typical installation of field drainage in the
demonstration area ................ 2.20
52 Relief drainage installation in the Grand Valley . . 122
53 Total project improvements in the Grand Valley
Salinity Control Demonstration Area, 1969-1976 . . 126
54 Advertising brochure and poster design for Irri-
gation Field Days ................. 136
55 Irrigation Field Days ................ 139
56 Cover of Irrigation Field Days report which was
printed in blues, greens, and white ........ 140
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57 Potential evapotranspiration, Etp, during the
1974-1976 irrigation season 145
58 Relative infiltration rate function for perennial
and annual crops in the Grand Valley 149
59 Seasonal distribution of computed application
efficiencies for common crops grown in the
Grand Valley 151
60 Differences in the estimation of the percent
moisture between the feel test and the oven-
dry value and the carbide test and the oven-
dry value 157
61 Identification of discharge points on Lateral
GV 95 178
62 Identification of discharge points for Lateral
GV 160 18°
xi
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LIST OF TABLES
Number
Page
1 Final Selection of Laterals Included in Project ... n
2 Soil Mapping Classified Index and Approximate
Percent of Areal Extent in Grand Valley,
Colorado ..................... 26
3 Land Use Summary by Canal in the Grand Valley,
Colorado 1969 ................... 34
4 Dimensions, Capacities, and Seepage Rates of
Canals in the Grand Valley, Colorado ....... 40
5 Water Budget Inflows to the Demonstration Area,
in Hectare-Meters ................. 52
6 Salt Budget Inflows to the Demonstration Area in
Metric Tons of Total Dissolved Solids ....... 53
7 Water Budget Groundwater Flows to the Demonstration
Area in Hectare-Meters .............. 54
8 Salt Budget Groundwater Salt Flows in the Demon-
stration Area in Metric Tons of Total Dissolved
Solids ...................... 55
9 Comparison of Seepage Rates Before and After Canal
Lining Using Ponding Tests ............ 53
10 Canal Lining Improvements Summary .......... 62
11 Results of Earlier CSU (1959-1970) Lateral Loss
Investigations .................. 63
12 Summary of the Sizes and Lengths of Laterals
Lined During the Earlier Years (1969 and 1970)
of the Project .................. 64
13 Land Use Data for the Lateral Systems for the
Project Period, in Hectares ............ 76
14 Annual Lateral Diversions in Hectare-Meters ..... 73
xii
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15 Summary of Project Improvements on the Lateral
Subsystems 124
16 Cost Summary of Project Improvements on the
Lateral Subsystems 125
17 Summary of Construction of Improvements by the
Grand Valley Salinity Control Demonstration
Project 127
18 Irrigation field Days Registration Breakdown 141
19 Evapotranspiration in the Grand Valley for 197£ ... 146
20 Summary of Application Efficiencies and Depths
of Deep Percolation for a Hypothetical Infil-
tration Model of the Grand Valley 150
21 Computed Deep Percolation in the Grand Valley .... 152
22 Annual Hydrologic Summary for Lateral HL C
Adjusted to 1976 Conditions 160
23 Annual Hydrologic Summary for Lateral HL E
Adjusted to 1976 Conditions 161
24 Annual Hydrologic Summary for Lateral PD 177
Adjusted to 1976 Conditions 163
25 Annual Hydrologic Summary for Lateral GV 95
Adjusted to 1976 Conditions 165
26 Annual Hydrologic Summary for Lateral GV 160
Adjusted to 1976 Conditions 166
27 Annual Hydrologic Summary for Lateral MC 10
Adjusted to 1976 Conditions 167
28 Annual Hydrologic Summary for Lateral MC 30
Adjusted to 1976 Conditions 170
29 Summary of Cost-Effectiveness Associated with
Individual Lateral Salinity Control Alter-
natives in Grand Valley 171
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LIST OF ABBREVIATIONS AND SYMBOLS
ac
AF
BTU
cal/gm
cfd
cf s
cmd
CMI
cms
degrees C or °C
degrees F or °F
ft
gin
gpm
ha
ha-m
hr
hp
in
km
kPa
Ib
Iph
1/min
— acre, (43,560 ft ) one acre equals 0.405
hectare
— acre-foot, volume of water to cover one
acre a depth of one foot, one acre-foot
equals 0.1233 hectare-meters
— British Thermal Unit
— calories per gram
— cubic feet per day
— cubic feet per second, volume flow rate of
water, one cfs equals 0.0283 cubic meter per
second
— cubic meter per day
— Colorado Miner's Inch, one Colorado Miner's
Inch equals 0.74 liters per second
— cubic meters per second, one cubic meter per
second equals 35.31 cfs
— centigrade temperature (also called Celsius)
scale
— Fahrenheit temperature scale
— feet, unit of length, one foot equals 0.3048
meters
— gram, 454 grams equal one pound
— gallons per minute, volume flow rate of
water, one gallon per minute equals 0.631
liters per second
— hectare, metric unit of area, one hectare
equals 2.471 acres
— hectare-meter, volume of water to cover one
hectare to a depth of one meter, one ha-m
equals 8.108 AF
— hour, 60 minutes
-- horsepower, one horsepower equals 7.460 x
10~5 erg/sec
— inch, one inch equals 2.54 centimeters
-- kilometer, metric unit of length, one
kilometer equals 0.621 miles
— kilopascal, metric unit of pressure, 6.9
kilopascal equals one psi
— pound (mass)
— liters per hour, volume flow rate of water
— liters per minute, volume flow rate of
water
xiv
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1/s
m
me/1
mg/1
mi
mm
mph
N/m
ppm
psi
sec
UCC
UCH
UCL
yd
liters per second, volume flow rate of water
meter
cubic meters per second, volume flow rate of
water
milliequivalents per liter
milligrams per liter, equal to one ppm
mile, one mile equals 1.609 kilometers
millimeter
miles per hour, velocity
Newton per square meter, unit of pressure,
one N/m^ equals one Pascal (6.9 kPa equals
one k)
parts per million
pounds force per square inch, unit of
pressure
seconds, time
Christiansen's Uniformity Coefficient
(Christiansen, 1942)
Hawaiian Sugar Planters Association
Uniformity Coefficient (Hart, 1961)
Linear Uniformity Coefficient (Karmeli, 1977)
yard, unit of length, one yard equals 0.9144
meters
cubic yard, unit of volume, one cubic yard
equals 0.7646 cubic meters
xv
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ACKNOWLEDGMENTS
The authors are deeply indebted to the many individuals who
carefully attended to the daily details of the field data collec-
tion and the laboratory analyses. These people include
Ms. Barbara Mancuso, Mr. John Bargsten, Mr. Forrest Binder/
Mr. Gregory Sharpe, Mr. David Flower, Mr. Douglas Ely, Mr. Patrick
O'Connor and Mr. Larry Rumburg. In addition, Mr. Richard L. Aust
and Mr. Stephen W. Smith contributed greatly towards the success
of the Irrigation Field Days.
The cooperation of all the landowners and irrigators on the
project who contributed labor, shared costs, and expended much
effort for the construction and operation of the lateral and on-
farm improvements is greatly appreciated. Their willingness to
participate in this investigation is undoubtedly one of the major
factors for the degree of improvement that was achieved.
The cooperation and assistance of the Grand Junction Drain-
age District was greatly appreciated and special thanks are due
Mr. Howard K. Hiest, Mr. Capper Alexander, Mr. Wesley Land, and
Mr. Bill Huber of the Board of Directors and Mr. Charles Tilton,
Superintendent, and their staff. Thanks also go to Mr. Charles
Bowman, Superintendent of the Mesa County Road Department and his
staff for their assistance in the project. The efforts and
assistance of Mr. Robert Henderson and the Directors of the Grand
Valley Irrigation Company, Mr. William Klapwyk and the Directors
of the Grand Valley Water Users Association, and the other irri-
gation companies in the area were extremely helpful. A complete
list of all other agencies and Grand Valley businesses who con-
tributed to this project would take several pages and, therefore,
a collective and heartfelt thanks goes to each of them.
The irrigation scheduling computer service was provided by
the Bureau of Reclamation, USDI, Grand Junction Office. We
gratefully recognize Mr. Bill McCleneghan, Mr. Blaine Richards,
Mr. Ray White, and Mr. Jack Ticen for their assistance.
Special acknowledgment goes to Ms. Debra Wilson and Ms. Sue
Eastman for typing the many drafts of this report.
Finally, the efforts and advice given by the EPA Project
Officer, Dr. James P. Law, Jr., have been extremely helpful in
the successful pursuit of this project. He has generously given
of his time to cooperatively achieve the goals of their project.
xv i
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SECTION 1
INTRODUCTION
BACKGROUND
Approximately 10 million metric tons (11 million tons) of
salts are delivered each year in the water supply serving the
Lower Colorado River Basin (Figure 1). These salts reach Hoover
Dam in about 1.36 million hectare-meters (11 million acre-feet)
of water. Studies have indicated that roughly 37 percent of
this salt load is to be contributed by irrigated agriculture in
the Upper Colorado River Basin (Figure 2). Present salinity
concentrations necessitate treatment of water for both municipal
and industrial uses throughout the Lower Basin. In fact/
concentrations at times approach the tolerance of many high-
value crops such as citrus, thus requiring the use of excessive
quantities of water for leaching and expensive water management
programs.
This situation is expected to become even more serious,
especially as many planned upstream water development projects
are constructed. Thus, a program for reduction of mineral
pollution is urgently needed in order to protect existing water
users from quality degradation during low flow periods and to
prevent the serious restriction of future basinwide economic
development. Due to the relatively large salinity contribution
from agriculture, it is obviously one sector in which to begin
implementation of technologies which will reduce the salt
loading from these areas.
The Grand Valley of Colorado is the largest contributor of
salts per hectare of irrigated land in the Upper Colorado River
Basin. Therefore, it was a logical place to begin investigating
salinity control alternatives. Water entering the near-surface
aquifers in the Grand Valley displaces highly mineralized water
into the Colorado River. In any area where the water is in
prolonged contact with soil, the mineral concentration of salts
will tend towards chemical equilibrium with the soil. In the
Grand Valley, high equilibrium salinity concentrations are known
to exist in the near-surface aquifer. The key to achieving a
reduction in salt loading is to reduce the groundwater inflows,
which will result in less displacement of water from the aquifer
into the river. In the Grand Valley, the main sources of ground-
water flows are conveyance seepage and deep percolation from
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/ s
/Wyoming___
'Utah'NJCojorado
IL Ynmnn f?
Figure 1. The Colorado River Basin.
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Upper Colorado River
Basin
Average Salt Load,Metric tons/day
Jun« 1983— May 1966
Natural Point Sourctt
and Wtllt
Irrigottd Agriculture
37%
(8750 T/d)
Ntt Runoff
52%
(72454 T/d)
Uppir Main Sttm
Subbatin
Relative Magnitude of Salinity
Sources by River Basins of the
Colorado River
Grttn Rivtr
Subbatin
Lowtr Main Stti
Subbotin
Son Juan Rivtr
Subbatin
Lower Colorado River
Basin
Average Salt Load,Metric tons /day
Novtmbtr 1963 -Octobtr 1964 / '9 » .
(1805 T/dr
Ntt Runoff / Natural
Point Sourctt
Upptr Colorado
Riv«r Batin
Inflow
72%
(6920 T/d)
Municipal
and
Industrial
Figure 2. Relative magnitude and sources of salt in the
Colorado River Basin (U.S. Environmental Protection
Agency, 1971).
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croplands resulting from relatively inefficient on-farm water
management practices.
Canal and lateral seepage can be greatly reduced by lininq
the delivery system. The Grand Valley Salinity Control Demon-
stration Project was initiated in 1968 to study the effectiveness
of linings as a salinity control measure. Since then, addi-
tional studies have been conducted on field drainage and
scientific irrigation scheduling as viable salinity reduction
technologies.
This demonstration project was established to show the
advantage of implementing a "package" of technological improve-
ments in reducing the quantity of highly saline subsurface
return flows reaching the Colorado River. The most significant
improvements in controlling irrigation return flow quality
potentially comes from improved on-the-farm water management.
This includes farm head ditch linings, water measurement, irri-
gation scheduling, conversion to sprinkler or trickle irrigation
gated pipe, cut-back furrow irrigation, field drainage, and
other types of on-farm water management improvements. This con-
cept of utilizing a package of appropriate technologies was
undertaken because many of these technologies complement each
other, and the net benefits would be expected to be greater than
the sum of the individual improvements. Also, results from the
concurrent EPA project "Irrigation Practices, Return Flow
Salinity, and Crop Yields," were utilized in predicting the
chemical quality changes in irrigation return flows to the
Colorado River as a consequence of the demonstration project.
The results of both projects were used in the development
of economically feasible guidelines for controlling the salinitv
from irrigation return flows. In addition, these studies should
be of assistance to the national need in developing mineral
pollution control methods for federal and private irrigation
projects. Results can also be used as a basis for salinity con-
trol recommendations to be incorporated in water resources proj-
ect evaluation reports and in programs to reduce water
degradation from irrigation return flows.
PURPOSE
The costs of salinity control to compensate for future
water resource developments in a region like the Colorado River
Basin will be high. Savings achieved through the implementation
of the most cost-effective alternatives can, therefore, be sub-
stantial. This project was designed to develop and demonstrate
cost-effectiveness relationships for salinity control in the
Grand Valley of western Colorado.
Economically feasible means of controlling salinity
associated with irrigation return flows had been evaluated
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individually and independently in previous investigations. In
order to extend these results to the formulation of comprehen-
sive plans for controlling salinity on a large scale, it was
necessary to describe the interrelationships which exist among
the alternatives. Prior to this project, some limited evidence
had indicated that the functions describing costs and effective-
ness of specific salinity control measures are nonlinear.
Therefore, if salinity control measures are not mutually exclu-
sive, then an "optimal" salinity control strategy would consist
of a combination of several alternatives. The respective com-
position of such a strategy would depend on the relative magni-
tude of each hydrologic segment in an irrigated area. Thus,
an important step in solving salinity problems was to investi-
gate the nature of improvements incorporating several alterna-^
tives, or in simpler terms, assessing the impact of a "package"
of salinity control measures.
OBJECTIVES
The primary objective of this demonstration project was to
show the advantages of implementing a "package" of technological
improvements within the lateral subsystems in reducing the salt
load entering the Colorado River. As defined in this project,
the lateral subsystem begins at the canal turnout and includes
all of the water conveyance channels below the turnout and the
farmlands served by the lateral subsystem. Although major
emphasis was upon on-farm improvements, considerable improve-
ments in the water delivery conveyances and some improvements
in lowering high water tables (drainage) were also required.
This project utilized each of the salinity control measures
previously evaluated in Grand Valley with the additional use of
various irrigation methods to demonstrate the complete package
of salinity control measures. No single measure will adequately
alleviate the salt load from an irrigated area. Demonstrating
the complete package of salinity control measures is not only a
"first," but the "packages" can also be expected to reduce the
salt load beyond the sum of each individual measure because of
improvements in the operation and management of each lateral.
The specific objectives of this demonstration project are
summarized below: .
A. Utilize salinity control technology to demonstrate the
complete package of salinity control measures for
nine laterals, including a preevaluation and post-
evaluation of the following control measures:
1. Utilization of existing canal lining technology
developed in the Grand Valley;
2. Utilization of irrigation scheduling technology
presently in use in the Grand Valley;
3. Evaluation of salinity control benefits resulting
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from various on-farm irrigation methods as a part
of this demonstration project;
4. Utilization of drainage technology previously
evaluated in the Grand Valley; and
5. Utilization of the concurrent EPA research project,
"Irrigation Practices, Return Flow Salinity,
and Crop Yields," to predict the chemical quality
changes in the Colorado River resulting from this
demonstration project.
B. Determine the cost-effectiveness of each salinity con-
trol measure, various combinations of salinity control
measures, and the complete package of salinity control
technology for this demonstration project.
C. Conduct a two-day highly publicized field days.
D. Determine the best practicable salinity control tech-
nology for the Grand Valley, including valley-wide
cost-effectiveness.
E. Analyze effectiveness of local administrative controls
in implementing salinity control technology.
1. Tailwater runoff control
2. Permit system
a. Individual farm
b. Lateral
c. Canal (Irrigation Co.)
d. Entire valley
3. Influent standards
a. Farm inlet
b. Lateral turnout
c. Canal diversion
F. Delineate the essential elements of an educational
program to transfer this information to other farmers
in the Grand Valley, along with farmers in other
irrigated areas of the Colorado River Basin.
This report covers all of the above objectives except A3
and D. The succeeding report "Evaluation of Irrigation Methods
for Salinity Control in Grand Valley" covers objective A3. The
final report of this research program, "Best Management Practices
for Salinity Control in Grand Valley," is devoted to satisfying
objective D.
APPROACH
The principal study area in the Grand Valley, which has
been used for evaluating the effectiveness of canal and lateral
lining, irrigation scheduling, and tile drainage in reducing
the salt load entering the Colorado River was also used in this
demonstration project (Figure 3). The advantage in continuing
to utilize this study area is that the hydrology is well known.
There has been considerable expenditure of funds in both equip-
ment and personnel for instrumenting this particular demonstra-
tion area. The wealth of available information provides a
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Grand Valley
Control Project
Boundary of Irrigated
Area
Gunnison
River
Figure 3. Location of Grand Valley Salinity Control Demonstration Project.
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strong basis for evaluating the effectiveness of salinity
control measures. Details of the demonstration area are shown
in Figure 4.
With all the available knowledge regarding the study area,
a lateral including the associated lands served by the lateral
water supply was used as a subsystem for evaluating the salinity
reduction in the Colorado River resulting from the implementa-
tion of a salinity control technology package. The study area
was originally selected because it is fairly representative of
the Grand Valley, and has five canals which traverse the area,
thereby allowing greater participation by the majority of
irrigation entities in the Valley.
In order to facilitate the continued participation by the
irrigation interests in the Grand Valley, the laterals were
selected to cover as many canals as possible. The final selec-
tion, as shown in Figure 5, had two laterals under the High-
line Canal, one under the Price Ditch, three under the Grand
Valley Canal, and three under the Mesa County Ditch. It should
be pointed out that the lands served by the Highline Canal in
the demonstration area are served under carriage contract with
the Mesa County Irrigation District (Stub Ditch) and the
Palisade Irrigation District (Price Ditch). Therefore, all the
irrigation entities in the demonstration area are involved
directly in the project.
The laterals were selected to capitalize on previous work
regarding canal and lateral lining, irrigation scheduling, and
drainage studies. The hydrologic knowledge already gained in
this demonstration area allowed routine surface water and
groundwater monitoring to evaluate the overall effectiveness of
the salinity control technologies. The lands which received
treatment under this demonstration project (about 20 percent of
the demonstration area), along with previously constructed
channel lining and drainage facilities, provided a significant
impact upon salinity leaving the demonstration area.
The experimental design for the preevaluation was primarily
aimed at providing specific information for the 330.7 hectares
(817 acres) undergoing treatment listed in Table 1. The field
data collection program allowed the design of irrigation and
drainage facilities and provided sufficient data to allow pre-
dictions of salinity benefits which resulted from each specific
salinity control measure. Although the postevaluation included
the monitoring of water and salts entering and leaving the
demonstration area, the primary emphasis was the on-site evalua-
tion of each specific salinity control measure. The on-site
evaluation was then compared with the results of the total
demonstration area hydro-salinity monitoring program.
-------
Stub Ditch
Government
Highline m
Canal
Legend
Canals
Washes and Drains
Scale I Mile
Figure 4. Grand Valley Salinity Control Demonstration Project Area.
-------
Scola I Mil*
Scale I Kilomtttr
I 1
Water Supply
Land UnderStudy Lateral
Hydrologlc Boundary
Canal or Ditch
. Drain or Wash
Grand Valley Canal
Stub Ditch
*
»
overnment
/ Highline
Canal
/' Price Ditch
rO
Figure 5. Location of the nine selected lateral subsystems incorporated in
the project.
-------
TABLE 1. FINAL SELECTION OF LATERALS INCLUDED IN PROJECT
Lateral
Identification
HL C
PD m-' -f
GV 92
GV 95 — —
GV 160
MC 3
MC 10^/
MC 30='
Canal
Highline Canal
Highline Canal
Price Ditch
Grand Valley Canal
Grand Valley Canal
Grand Valley Canal
Mesa County Ditch
Mesa County Ditch
Mesa County Ditch
TOTAL
Area
Hectares
13.1
35.9
27.8
24.3
79.1
78.7
3.7
54.0
14.1
330.7
Acres
32.4
88.6
68.8
59.9
195.7
194.3
9.0
133.4
34.7
816.8
No. of
Irrigators—
1
2
6
6
13
8
1
9
1
47
I/ These laterals were part of the earlier EPA funded canal and lateral
lining study.
2/ This lateral was part of the earlier EPA funded field drainage study.
3_/ This lateral consolidated an additional 70 acres from two other
laterals.
4_/ A portion of this lateral was included in the previous EPA funded
irrigation scheduling program.
5/ An irrigator is defined as a person who farms more than one acre.
In actuality, 89 persons are involved in the operation of this
project.
The selection of a lateral as a subsystem, rather than an
individual farm, had a tremendous advantage in allowing control
at the lateral turnout. In this way, both the quantity of flow
and the time of water delivery could be controlled, facilitating
improved water management throughout the subsystem.
A variety of irrigation methods have been demonstrated,
including "tuning up" present irrigation methods being used in
the study area. Considerable experience has been gained in
improving the existing irrigation methods while evaluating irri-
gation scheduling as a salinity control measure in the Grand
Valley. In addition, more advanced irrigation methods have been
evaluated as to salinity benefits in the Grand Valley. The
irrigation systems constructed under this project included auto-
mated farm head ditches, sprinkler irrigation, and trickle
irrigation.
The most significant aspect of this particular demonstration
project is the employment of a salinity control technology
"package," rather than a single control measure. Experience in
11
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the Grand Valley has shown that the most significant progress
is made when the gamut of questions can be answered regarding
the interrelationships between water management and agricultural
production. The concept of a technology package, along with an
understanding of the "system" including other agricultural
inputs, provides the necessary base for providing sound advice
to the farmer. This, in turn, facilitates the development of
credibility and, consequently, farmer acceptance.
A two-day "Field Days" was conducted during the third year
of this project in the month of August. This event was primarily-
directed towards the growers in the Grand Valley and secondly
to irrigation leaders (mostly growers) throughout the Upper
Colorado River Basin. State and Federal agency personnel also
attended. This was coupled with an irrigation equipment show
and was cosponsored by the Colorado State University Cooperative
Extension Service.
The concurrent EPA research project, "Irrigation Practices,
Return Flow Salinity, and Crop Yields," which was also conducted
in the Grand Valley, provided necessary input for developing the
cost-effectiveness of each salinity control measure. The results
from that project provided valuable information regarding
increased crop yields that can be expected from improved water
management practices. The combined results of these two projects
are extremely important in establishing the benefits to be
derived from implementing a salinity control technology package.
The detailed results of this project can be found in the EPA
reports entitled, "Potential Effects of Irrigation Practices on
Crop Yields in Grand Valley" and "Irrigation Practices and Return
Flow Salinity in Grand Valley." The combined results of the two
projects are incorporated in the EPA report "Best Management
Practices for Salinity Control in Grand Valley."
As a part of the demonstration project, the effects of
various institutional influences upon salinity control were
analyzed. These included the effects of tailwater runoff con-
trol, the requirements for implementing a permit system, and the
alternative of setting "influent" standards. The information
necessary for analyzing the effects of each of the above alter-
natives was collected as a part of the demonstration project.
To allow the analysis to be projected valley-wide, some field
data were collected on a random sample basis throughout the
Valley.
Although not all of the institutional alternatives for
implementing salinity control technology were thoroughly
analyzed under this demonstration project, every attempt was
made to collect the necessary "field" data for assessing the
constructed alternatives. Thus, any remaining alternatives must
be analyzed on a much larger scale (i.e., regional, state, or
federal). Even though each irrigated area is somewhat different,
12
-------
the knowledge gained in the Grand Valley can be utilized in
conjunction with existing and secondary sources of data for
other areas (particularly irrigated areas in the Upper Colorado
River Basin) to formulate plans and priorities for implementing
agricultural salinity control programs in such areas.
As a final phase of the project, activity was undertaken
to outline and identify the necessary elements of an educational
program. This program delineates the sources of. agricultural
water quality problems and the effective methods for managing
irrigated agriculture to improve water quality.
13
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SECTION 2
CONCLUSIONS
The salinity control cost-effectiveness associated with each
alternative improvement is the basis for determining the formu-
lation of an implementation policy. Studies reported in the
technical literature indicate that the salinity damages in the
Lower Colorado River Basin range from $150 to $350 per metric
ton per year when extended to the Grand Valley. Local benefits
to the project such as increased crop yields, reduced irrigation
system maintenance costs, increased land values and other
factors were not evaluated as part of this report and are not
included in the cost-effectiveness of the various alternatives.
In terms of dollars per unit of annual salt load reduction
achieved, the most cost-effective measures were:
1) Concrete slip form or low head PVC plastic conduit
lining of laterals. The two methods are almost equal
in cost-effectiveness and can reduce salinity at
substantially less cost than the $150/metric ton value.
Concrete slip form linings offer the advantages of
easier and less frequent maintenance than pipelines,
and they are more acceptable to local irrigation.
Pipelines, on the other hand, are easier and more
rapidly installed and can be installed by the farmer
as part of his matching requirements.
2) Use of high-head PVC pipe or concrete pipe is not a
cost-effective alternative to concrete linings or low-
head PVC and should be discouraged. Attendant problems
with the use of low-head pipe can be overcome by giving
particular attention to design and installation
specifications.
3) Field head ditch lining by concrete slip form or gated
pipe have comparable cost-effectiveness values, and
while costing more than twice as much as lateral linings
to remove a unit of salinity, they still cost consid-
erably less than the $150/metric ton value.
4) Automation of irrigation systems through automated
cut-back surface irrigation, sprinkler or trickle
irrigation are somewhat more costly than the
14
-------
nonautomated systems, but offer a larger potential for
reducing on-farm salinity contributions due to increased
irrigation efficiencies. Sprinkler and trickle irri-
gation systems are not competitive with head ditch
linings whereas automated head ditches can compete and
can increase the cost-effectiveness of head ditch
linings. Sprinkler and trickle irrigation systems
become feasible near the $150/metric ton value.
5) Irrigation scheduling by itself is not a significant
salinity control alternative, but should be part of any
strategy for improved water management in order to
maximize the effectiveness of physical improvements.
6) Canal linings reduce salt loading at unit costs
ranging from $190 to $700 per metric ton of salt
removed.
7) Desalting in conjunction with pump drainage can be
expected to become feasible to reduce salt loading at
approximately $320 per metric ton.
8) Field relief drainage is infeasible at any cited down-
stream detriment figure.
9) Cost-sharing programs are highly effective in attracting
irrigators to participate in programs for improving the
lateral and on-farm components of the irrigation system,
provided adequate technical assistance is provided.
10) Allowing individual irrigators to use their labor to
meet all or part of their matching requirements cer-
tainly contributed to the ease of accomplishing the
goals of this project.
11) In Grand Valley, the jurisdiction of the irrigation
companies does not include the laterals in most cases,
so there are no formal arrangements for managing the
irrigation water supply and settling disputes among
water users.
12) The informal organizational arrangements used for the
lateral improvement program, although satisfactory on
most of the laterals, resulted in numerous problems on
a few laterals as far as collecting required matching
funds for the project, as well as some difficulties in
implementing improved irrigation practices.
13) Individual on-farm improvements should be the result of
individual negotiations between the irrigator and tech-
nical assistance personnel.
15
-------
14) There is a clear need to involve irrigators in all
phases of salinity related improvements. Where irri-
gators participated in design decisions, the systems
were not always the most efficient, but were certainly
the most workable and flexible from the standpoint of
the water users. Participation in the actual construc-
tion provided operational insight, understanding of
neighbor needs, a pride in workmanship, and more rapid
completion of the work than by contractual methods.
15) Proper water management requires a strong emphasis toward
on-farm water control structures, especially flow meas-
urement devices. This project utilized standardized
means for determining water flow rates. All flow
measurement devices were designed or selected to be
read directly by the farmers without the use of printed
tables.
16) In investigating the advantages and disadvantages of
influent control versus effluent control for a National
Pollutant Discharge Elimination System type program in
Grand Valley, it became readily evident that influent
controls offered the greatest advantage in terms of the
reduced number of control points, better monitoring
capabilities, and most importantly, being able to
alleviate the problem at its source rather than treating
the symptoms.
17) The success of an influent approach is dependent upon:
(a) use of numerous flow measuring devices; (b) adequate
technical assistance for working with and advising
farmers on improved irrigation practices and methods;
and (c) availability of funds for making the necessary
structural improvements.
18) Successful implementation requires large-scale extension
type programs to provide necessary technical assistance
and a strong interaction with farmers.
19) A large amount of technical assistance is required in
working with farmers in designing on-farm improvements
that suit their individual needs, to negotiate the
financial terms, construction of the improvements, and
assisting the irrigator in the proper management of his
new system.
16
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SECTION 3
RECOMMENDATIONS
As a result of this rather extensive research project,
there are several recommendations which can be made concerning
the implementation of a "total" salinity control program.
1) Implementation of an action salinity control program
in the Grand Valley should consist of lateral improve-
ments (i.e., concrete slip form lining or low-head
PVC plastic pipe) and on-farm improvements.
2) The lateral improvement program and the on-farm program
should not be two separate programs, but a single
program which plans, constructs, and operates a combi-
nation of improvements moving from one lateral to the
next.
3) Open hearings or public meetings must be followed up
by additional contact with all the farmers on a lateral
which have expressed an interest. Meetings at the
irrigation company offices or in local homes will be
much more effective in reaching many landowners.
4) For lateral improvement programs which require the
collective action of the irrigators served by a lateral,
there is a need to encourage the users to formally
organize under the corporate laws of the State of
Colorado that apply to irrigation, which will: (a)
substantially facilitate contractual arrangements for
lateral improvements; (b) provide a much simpler means
of handling matching requirements; and (c) provide a
better means for implementing a more comprehensive
water management program for each lateral.
5) Training materials are needed to motivate farmers and
help them understand the importance to themselves and
their communities of improving present water management
practices for increased crop production and the control
of salinity.
6) An effective plan of physical improvements must be
developed which will result in improved water management
17
-------
for increasing agricultural productivity in the Grand
Valley, while reducing the salt load in the Colorado
River.
7) The plan of improvement must include sufficient flow
measurement structures through the lateral subsystem to
facilitate equitable distribution of the water supplies
and improved irrigation practices.
8) Adequate numbers of technical assistance personnel
should be available to help the irrigators develop
proficiency with their system and develop a higher level
of water management.
9) Given the levels of technical assistance personnel
needed to work with farmers, and the current shortage
of trained manpower with on-farm water management
experience, special training courses will be required.
10) Once the physical facilities are complete, a program of
"scientific" irrigation scheduling should be used to
maximize the effectiveness of the physical improvements.
11) The success of any salinity control program rests
finally with the degree of participation by the farmers
themselves. Farmers who have made exceptional progress
in improving their on-farm water management practices
should be given special recognition.
12) The implementation program should be monitored, evalu-
ated, and continuously refined. This process will not
only maximize the effectiveness of the Grand Valley
Salinity Control Program, but will provide valuable
information and experience for implementing irrigation
return flow quality control programs in other areas of
the West.
18
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SECTION 4
THE GRAND VALLEY
The Grand Valley is located in west central Colorado near
the western edge of Mesa County. Grand Junction, the largest
city in Colorado west of the Continental Divide, is the popula-
tion center of the Valley (Figure 3). The Grand Valley is a
crescent shaped area which encompasses about 49,800 hectares
(123,000 acres) of which 57.7 percent or about 28,650 hectares
(70,800 acres) are irrigated. Urban and industrial expansion,
service roads and farmsteads, idle and abandoned lands account
for most of the land not farmed. The Valley was carved in the
Mancos Shale formation (a high salt bearing marine shale) by
the Colorado River and its tributaries. The Colorado River
enters the Grand Valley from the east, is joined by the Gunnison
River at Grand Junction and then exits to the west.
Spectacular and colorful canyons flank the southwestern
edge of the Valley (Colorado National Monument). A steep escarp-
ment known as the Book Cliffs (which are the southern edge of
the Roan Plateau) rises from the Valley floor on the north; the
3,050 meter (10,000 foot) high Grand Mesa lies to the northeast,
and distantly to the southeast the San Juan Mountains can be
seen; to the south and west lie the rough, steep, deeply eroded
hilly lands of the high terraces or mesas of the canyon lands of
the Colorado Plateau. Within the Grand Valley, the irrigated
lands have developed on geologically recent alluvial plains
consisting of broad coalescing alluvial fans and on older
alluvial fans, terraces and mesas. Also, included in the Valley
lands are stream flood plains and various rough lands occurring
as terraces, escarpments, high knobs, and remnants of former mesas,
POPULATION
The majority of the population of Mesa County resides in
the Grand Valley near and within the city limits of Grand
Junction. In 1970 the population of the city of Grand Junction
was 20,170, 37 percent of the total Mesa County population. The
population has been growing steadily during the past decades,
and the 1974 estimated population of Grand Junction was 27,000
while that of the Mesa County was nearly 62,000. The projected
1990 population of Mesa County is 90,000.
19
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Grand Junction is a regional trade and service center for
the considerable agricultural and mining interests in western
Colorado, northwestern New Mexico, northeast Arizona, and
eastern Utah because of its access to major highways, rail and
airline systems. During the 1950's the area became and still is
the center of the uranium exploration boom and several uranium
development projects sponsored by the government. Recent pro-
gram expansions related to energy have caused an economic
upswing for the area. At the present time, the Grand Valley is
a focal supply point for the budding oil shale and sodium
bicarbonate (Nahcolite) industries which lie to the north and
west. The area is also a supply and service center for a con-
siderable oil and natural gas drilling and exploration industry.
CLIMATE
The Grand Valley area enjoys a moderate year-around climate
which is influenced more by the mountain ranges in the Upper
Colorado River Basin than by the latitude. The movement of air
masses are affected by the mountain ranges so that the high
elevations are relatively wet and cool, whereas the low plateaus
and valleys are much drier and subject to wide temperature
ranges. The characteristic climate in the lower altitudes is
hot and dry summers and cool winters.
The Grand Valley has a climate common to all of the semi-
arid Colorado River Basin. Most of the precipitation to the
Valley is provided from the Pacific Ocean and the Gulf of
Mexico, whose respective shores are 1,200 and 1,800 kilometers
(750 and 1,100 miles) away. During the period from October to
April, Pacific moisture is predominant, but the late spring and
summer months receive moisture from the Gulf of Mexico. The
advancing air masses are forced to high altitudes and lose much
of their moisture either before entering the area (Gulf of
Mexico fronts) or after leaving the area (Pacific fronts).
The Grand Valley receives an average annual precipitation
of only 211 mm (8.29 inches) and practically all irrigation and
potable water supplies come from the nearby high mountain snow-
packs. The monthly distribution of precipitation and tempera-
ture for Grand Junction is shown in Figure 6. The climate is
marked by a wide seasonal range, but sudden or severe weather
changes are infrequent due primarily to the high mountains
around the Valley. The usual occurrence of precipitation in the
winter is snow and during the growing season is in the form of
light showers from thunderstorms. Severe cloudbursts occur
infrequently during the late summer months and hail storms are
rare.
Although temperatures have ranged to as high as 40.6
degrees C (105 degrees F), the usual summer temperatures range
to the middle and low 30's degrees C (90's degrees F) in the
20
-------
Grand Junction Colo.
Alt. 4843 ft. - 1476 meters
o
o
a>
0
8. 29" Annual
210.57mm Annual -30
~
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FMAMJ JASOND
Month
a
a
-10 §
a>
Figure 6. Normal precipitation and temperature at Grand
Junction, Colorado (U.S. Department of Commerce,
1968).
21
-------
daytime and around 15 degrees C (low 60's degrees F) at night.
Relative humidity is usually low during the growing season,
which is common in all of the semi-arid Colorado River Basin.
The average annual relative humidity is 58.8 percent. The
prevailing wind direction is east-southeast with an average
velocity of about 13.4 kilometers per hour (8.3 mph).
GEOLOGY
The plateaus and mountains in the Colorado River Basin are
the products of a series of land masses deeply eroded by wind
and water. However, long before the earth movements which
created the uplifted land masses, the region was the scene of
alternate encroachment and retreat of great inland seas. The
sediment rock formations underlying large portions of the basin
are the result of material accumulated at the bottom of these
seas. In the Grand Valley, the primary geologic formation is
the Mancos Shale.
Mancos Shale is a very thick sequence of drab, gray,
fissile, late Cretaceous marine shale that lies between the
underlying Dakota sandstones and the overlying Mesa Verde
formation. The thickness of the Mancos Shale usually varies
from between 900 to 1,500 meters (3,000 and 5,000 feet). Due
to its great thickness and its ability to be easily eroded, this
shale forms most of the large valleys of western Colorado and
eastern Utah. A general geologic cross-section of the Valley
can be seen in Figure 7.
Because of the marine origin of the shale, it contains a
very high percentage of water soluble salts which can be readily
seen in the many patches of alkali (white and black) in both
irrigated and nonirrigated areas. The types of salts which are
present in the shale are mostly calcium sulfate with smaller
amounts of sodium chloride, sodium sulfate, magnesium sulfate,
and calcium and magnesium carbonates. In fact, the minerals
gypsum and calcite (calcium sulfates) are commonly found in
crystaline form in open joints and fractures of the Mancos
Shale, as well as in the soil profile. This can be seen in
Figure 8.
Due to the compactness of the clay and silt particles
making up the shale, the formation is not considered water-
bearing at depth. However, the weathered zone near the surface
does transmit small quantities of water along joints, fractures,
and open bedding planes, in this zone, the percolating water,
which primarily originates from the overirrigation of cropland,
dissolves the salts directly out of the shale. The soils of
the Valley are also quite saline because they have been derived
from the Mancos Shale.
22
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UNCOMPAHGRE UPLIFT
GRAND MESA
,AVA—S75v CENOZOIC
TERTIARY
(EOCENE)
ttYZ (PAL EOCENE I
. GRANITE . GNEISS •- '.
- NAMPHIBOLITE,ETC .. /_
f
ARCHEZOIC
Figure 7. General geologic cross-section of the Grand Valley (U.S. Department of Agri-
culture, Soil Survey, Series 1940, Grand Junction Area, Colorado, 1955).
-------
Figure 8. Photograph of crystaline salt
lenses in Mancos Shale in the
irrigated area of the Grand Valley.
A gravel and cobble layer has been found under some parts
of the irrigated areas in the Grand Valley. It is believed to
be ancient stream deposits of the Colorado River, laid down in
recent geologic time, and serves as an aquifer for transmitting
highly saline groundwater to the river.
SOILS
The physical features describing the project area are
similar to the entire Grand Valley. The soils in the Valley
were classified by the Soil Conservation Service (SCS) in
cooperation with the Colorado Agricultural Experiment Station in
1955. Using these data a soil classification map of the Grand
Valley's irrigated area is shown in Figure 9. The soil classi-
fication symbols, along with a general description of each
symbol and the relative percent of areal extent, are tabulated
in Table 2.
The dry desert climate of the area has restricted the
growth of natural vegetation, and because of the lack of organic
matter, the soils are very low in nitrogen content. The natural
inorganic content is high in lime carbonate, gypsum, sodium,
potassium, magnesium and other calcium salts. With the addition
of irrigation, some locations have experienced high salt con-
centrations with a resulting decrease in crop productivity.
Although natural phosphate exists in the soils, it becomes
available too slowly for use by cultivated crops, and fertilizer
24
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|SJ
Jl
LEGEND
Billings Silty Cloys
Chipeto - Persoyo Looms
Chipela Silty Cloy Loom
Fruito and Ravola Loams
Fruilo Looms
| Genola Loams
| Green River Loams
| Hinman Clay
| Mock Clay Loams
| Mayfield Shaly Clay Loam
Mesa Clay Loams
Naples Loams
Persayo-Chipeta Silty Clay Loam
Ravola Loams
Redlands Loams
Bfflffl! Red lands and Thoroughfare Soils
[ I Riverwash
gggg Rough Broken Land: Mesa, Chipeta,ft Persayo S
fc-~->3j Rough Gullied Land
PJgJ^ij Thoroughfare Fine Sandy Loam
Figure 9.
Soils map of irrigated lands in Grand Valley
-------
TABLE 2. SOIL MAPPING CLASSIFIED INDEX AND APPROXIMATE
PERCENT OF AREAL EXTENT IN GRAND VALLEY, COLORADO
(USDA, SOIL SURVEY, SERIES 1940, 1955).
MaP Approximate
Symbol Soil Type Percent
Be
Bd
Ba
Bb
Be
Cd
Ce
Ca
Cb
Cc
Fe
Ff
Fg
Fl
Fi
Fk
Fm
Fn
Fo
Fp
Fr
Fs
Ft
Fu
Fc
Fd
Fa
Fb
Ga
Gb
Gc
Gd
Gf
Gq
Gh
Gk
(Table
Billings silty clay loam, 0 to 2 percent slopes
Billings silty clay loam, 2 to 5 percent slopes
Billings silty clay, 0 to 2 percent slopes
Billings silty clay, 2 to 5 percent slopes
Billings silty clay, moderately deep over Green River
soil material, 0 to 2 percent slopes
Chipeta silty clay loam, 0 to 2 percent slopes
Chipeta silty clay loam, 2 to 5 percent slopes
Chipeta-Persayo shaly loams, 2 to 5 percent slopes
Chipeta-Persayo shaly loams, 5 to 10 percent slopes
Chipeta-Persayo silty clay loams, 5 to 10 percent slopes
Fruita clay loam, 0 to 2 percent slopes
Fruita clay loam, 2 to 5 percent slopes
Fruita clay loam, moderately deep, 0 to 2 percent slopes
Fruita clay loam, moderately deep, 2 to 5 percent slopes
Fruita gravelly clay loam, 2 to 5 percent slopes
Fruita gravelly clay Loam, 0 to 2 percent slopes
Fruita gravelly clay Loam, 5 to 10 percent slopes
Fruita gravelly clay Loam, moderately deep, 2 to 5
percent slopes
Fruita gravelly clay Loam, moderateLy deep, 5 to 10
percent slopes
Fruita very fine sandy Loam, 0 to 2 percent slopes
Fruita very fine sandv loam, 2 to 5 percent slopes
Fruita very fine sandy loam, moderately deep, 0 to 2
percent slopes
Fruita very fine sandy loam, moderately deep, 2 to 5
percent slopes
Fruita very fine sandy loam, moderately deep, 5 to 10
percent slopes
Fruita and Ravola Loams, 2 to 5 percent slopes
Fruita and Ravola loams, moderately deep, 2 to 5
percent slopes
Fruita and Ravola gravelly loams, 5 to 10 percent
slopes
Fruita and Ravola gravelly loams, 20 to 40 percent
slopes
Genola clay loam, 0 to 2 percent slopes
Genola clay loam, 2 to 5 percent slopes
Genola clay loam, deep over Hinman clay, 0 to 2
pprcent slopes
Genola fine sandy loam, deep over gravel, 0 to 2 1
percent slopes
Genola loam, 2 to 5 percent slopes
Genola very fine sandy loam, deep over gravel, 0 to
2 percent slopes
Green River clay loam, deep over gravel, 0 to 2
percent slopes
Green River fine sandy loam, deep over gravel, 0 to 2
percent slopes
2 continued on following page)
25.4
.6
2.7
.1
.7
2.4
2.8
.8
1.9
1.5
2.2
.4
.6
1.1
.6
.1
.1
.5
.1
1.1
.5
.5
1.0
.1
1.2
. 3
.7
.1
.2
.5
.2
.1
.1
.4
26
-------
TABLE
Map
Symbol
Gl
Gm
Ha
Hb
He
Ma
Mb
Me
Md
Me
Mf
Mg
Mh
Na
Mb
Nc
Pa
Pb
Ra
Rb
Rf
Rg
Re
Rd
Re
Rk
Rh
Rl
Rn
Rro
Ro
Rr
Rp
Rs
Tb
Ta
Tc
2 (CONTINUED) .
Approximate
Soil Type Percent
Green River silty clay loam, deep over gravel, 0 to
2 percent slopes
Green River very fine sandy loam, deep over gravel,
0 to 2 percent slopes
Hinman clay, 0 to 1 percent slopes
Hinman clay loam, 0 to 2 percent slopes
Hinman clay loam, 2 to 5 percent slopes
Mack clay loam, 0 to 2 percent slopes
Mayfield shaly clay loam, 2 to 5 percent slopes
Mesa clay loam, 0 to 2 percent slopes
Mesa clay loam, 2 to 5 percent slopes
Mesa gravelly clay loam, 2 to 5 percent slopes
Mesa gravelly clay loam, 5 to 10 percent slopes
Mesa gravelly clay loam, moderately deep, 2 to 5 percent
slopes
Mesa gravelly clay loam, moderately deep, 5 to 10
percent slopes
Naples clay loam, 0 to 2 percent slopes
Naples fine sandy loam, 0 to 2 percent slopes
Navajo silty clay, 0 to 2 percent slopes
Persayo-Chipeta silty clay loams, 0 to 2 percent slopes
Persayo-Chipeta silty clay loams, 2 to 5 percent slopes
Ravola clay loam, 0 te 2 percent slopes
Ravola clay loam, 2 to 5 percent slopes
Ravola very fine sandy loam, 0 to 2 percent slopes
Ravola very fine sandy loam, 2 to 5 percent slopes
Ravola fine sandy loam, 0 to 2 percent slopes
Ravola fine sandy loam, 2 to 5 percent slopes
Ravola loam, 0 to 2 percent slopes
Red lands loam, 2 to 5 percent slopes
Red lands loam, 0 to 2 percent slopes
Redlands loam, 5 to 10 percent slopes
Redlands and Thoroughfare soils, shallow over bedrock,
5 to 10 percent slopes
Redlands and Thoroughfare soils, shallow over bedrock,
2 to 5 percent slopes
Riverwash, 0 to 2 percent slopes
Rough broken land, Mesa, Chipeta, and Persayo soil
materials
Rough broken land, Chipeta and Persayo soil materials
Rough gullied land
Thoroughfare fine sandy loam, 2 to 5 percent slopes
Thoroughfare fine sandy loam, 0 to 2 percent slopes
Thoroughfare fine sandy loam, 5 to 10 percent slopes
.2
1.7
.5
1.7
.3
.5
.5
1.7
1.8
1.3
.7
.1
.4
.1
.1
.1
3.4
2.5
6.1
.4
4.7
.1
2.1
.1
2.1
.8
.1
.4
2.9
3.6
2.9
2.9
1.4
.1
.1
I Less than 0.1 percent.
27
-------
applications greatly aid yields. Other minor elements such as
iron are generally available for most crops except in those
areas where drainage is inadequate. The soils in the area are
of relatively recent origin, and consequently, they contain no
definite concentration of lime or clay in the subsoil horizons
as would be expected in weathered soils. Some areas in the
Valley have limited farming use because of poor internal drain-
age, which results in waterldgging and salt accumulations.
Lying on top of the Mancos Shale and below the alluvial
soils is a large cobble aquifer extending north from the river
to about midway up the irrigated area for most of the length
of the Valley. The approximate areal extent of this aquifer
can be seen in Figure 10. The importance of this aquifer with
respect to the drainage problems of the area has been demon-
strated by a cooperative study in 1951 between the Colorado
Agricultural Experiment Station in conjunction with the United
States Department of Agriculture, Agricultural Research Service
(ARS), which evaluated the feasibility of pump drainage from
the aquifer. Much of this cobble aquifer is covered with a
thin, tight and often discontinuous clay layer and/or a shale
gravel washed from the nearby Book Cliffs.
AGRICULTURAL ECONOMIC CONDITIONS
The modification of the Colorado River's flows have yielded
benefits in the form of irrigation, power generation, recreation
industrial and domestic water supply, transportation and waste '
disposal. In recent years, manufacturing and service industries
have experienced rapid growth, surpassing mining and agriculture
in economic importance in all seven basin states. Agriculture
is an important source of employment and income to a local
population in the Grand Valley area. In recent years, basic
manufacturing and service industries have greatly contributed
to the otherwise traditionally agricultural community.
In 1972, the annual per capita income for Mesa County was
$3,409 compared to the Colorado per capita income of $4,006.
The unemployment is generally less than the statewide level
(October 1976 it was 4.3 percent compared to 5.3 percent for
the state). In 1970, the median income for families was $8,065
for Mesa County. Farm population in Mesa County for 1970 was
3,898 which was a 42.7 percent decline from 1960.
The Grand Valley contains approximately 65 percent of the
total irrigated croplands in Mesa County and accounts for
about 75 percent of total value of farm products for the county.
The 1969 census (by U.S. Department of Commerce definition, 1972)
counted a total of 1,320 farms for Mesa County, which was a
21 percent decrease since 1964.
28
-------
ID
Legend
Boundary of Irrigated Area
Grand Valley Salinity Control
Demonstration Project
Approximate Extent of Cobble
Aquifer
Scale in Kilometers
Figure 10. Approximate areal extent of cobble aquifer in the Grand Valley.
-------
The diversified agricultural industry in the Valley is
comprised of both livestock and crop production activities.
Slightly less than 10 percent of the irrigated acreage is planted
to pome and deciduous orchards, the produce of which is processed
locally and may be shipped as far as the Atlantic seaboard. The
Grand Valley has long been a favored wintering area for cattle
and sheep which were grazed on high mountain summer ranges to
the east and north (Young et al., 1975).
An economic survey by Leathers (1975) , along with the land
use inventory by Walker and Skogerboe (1971), indicates that
local farming is primarily a small unit operation. The popula-
tion engaged in agricultural activities is widely dispersed
throughout the Valley with most living on their property.
Leathers (1975) determined from sampling about 100 random selec-
tions that most farm units were less than 40 hectares (100 acres)
in size (Figure 11). Using data supplied by the USDA Soil
Conservation Service, a frequency distribution of field sizes
is shown in Figure 12. Of the total of 7,870 fields in the
Valley, 50 percent are less than 2 hectares (5 acres) in size.
AGRICULTURAL LAND USE
Although the early explorers concluded that the Grand
Valley was a poor risk for agriculturally related activities,
the first pioneering farmers rapidly disproved this notion with
the aid of irrigation water diverted from the Grand and Blue
Rivers (now the Colorado and Gunnison Rivers) entering the
Valley. Through a long struggle/ an irrigation system evolved
to supplement the otherwise meager supply of precipitation
during^the hot summer months. However, the futility of irriga-
tion without adequate drainage was quickly demonstrated in the
Valley as some low lying acreages became waterlogged with highly
saline groundwater. Today, the failure to completely overcome
these conditions is still evident as illustrated by a summary
of land use in the Valley presented in Figure 13. For example
of the more than 28,600 hectares (70,800 acres) of irrigable
cropland, almost one-third is either in pasture or idle. An
examination of land use in Grand Valley by Walker and Skogerboe
(1971) indicated a large fraction of the 12,000 to 16,000
hectares (30,000 to 40,000 acres) of phreatophytes and barren
soil were also once part of an irrigated acreage. Evidence
exists that these same lands were once highly productive and
subsequently ruined by overirrigation and inadequate drainage.
The various acreages of land uses in the Valley area are
shown in Table 3. One of the most quoted statements in the
literature concerning the Grand Valley is that approximately 30
percent of the farmable area is unproductive because of the
ineffectiveness of the drainage in these areas. Examination of
the results presented in Table 3 indicates that 58 percent of
the Valley can be classified as usable land. However, only 43
30
-------
100 r
U)
0
100 200 300
Net Cropped Acreage per Farm
400
500
Figure 11. Frequency distribution of Grand Valley farm sizes (Leathers, 1975)
-------
100
Field Size in hectares
6 8 10 12
15 20 25 30
Field Size in acres
35
40
45
Figure 12
Frequency distribution of agricultural field sizes in the Grand Valley
(USDA-SCS. Open file data, 1976).
-------
120
100
tn
t-
O
O
80
o
o
o.
c
si 6°
o
o>
0
*5
Q)
J ^ r\
*rU
TJ
C
o
20
o
_
-
.
-
Sugar Beets
Orchards
Grain
Idle
Pasture
Corn
Alfalfa
Irrigable
miscellaneous
Industrial
Municipal
Municipal-
Croplands Industrial
Open Water
Phreatophytes
Barren
Soil
Phreatophytes
Open Water
Municipal -
Industrial
Phreatophytes
and
Barren Soil
Irrigable
Croplands
-
v/^pX
40
a>
30 2
o
O>
JC
O
O
—
c
r\f\ _
20 J
«n
•O
C
0
10
n
Total
Surfaces ona
Figure 13. Agricultural land use in the Grand Valley (Walker
and Skogerboe, 1971).
33
-------
TABLE 3. LAND USE SUMMARY BY CANAL IN THE GRAND VALLEY^^COLORADO 1969 (IN HECTARES)
10
Land Use Classification
Corn
Suqar beets
Potatoes
Tomatoes
Truck Crop
Barley
Oats
Wheat
Alfalfa
Native Grass Hay
Cultivated Grass Hay
Pasture
Wetland Pasture
Native Pasture
Orchard
Idle
Other
Farmsteads
Residential Yards
Urban
Stock Yards
Refineries
Miscellaneous Industrial
Natural Ponds
Cottonwoods (H) f
Cottonwoods (M)*
Cottonwoods (L) *
Salt Cedar (H)
Salt Cedar (Ml
Salt Cedar (L)
Willows (H)
Willows (M)
Willows (L)
cattails IH>
.-^ttails {Ml
ireasewooa mi
Grsasewood (M)
Gieasewood fL)
Shrubs: Wild Rose Etc. (HI
5iiru*>9 ^*'t
Shrubs (L)
Grasses and.-^r Sedqes(H)
brasses and/or Sedges (L)
oreripitation Only
TOTAL
*Note: H « Heavy cover, M
Stub
Oitcn
71
33
97
6
43
247
111
25
5
2
31
4
2
7
16
20
2
51
77}
• Medium
Gov' t
Hiqhline
Canai
5979
3452
95
31
161
1644
963
15
7019
450
1533
11
47
695
2948
126
685
28
759
157
63S
612
2262
108
4
10
344
2928
205
78
3
10,429
44,416
cover, L * »
Price
Ditch
535
2
263
70
22
551
35
109
369
198
1575
571
6
108
163
264
12
37
10
24
13
16
11
7
9
13
62
12
337
>404
.iqht cover.
Grand
Valley
Canal
6671
1726
96
133
147
2311
1515
63
5206
84
1531
3642
538
514
4219
11
1221
34
3925
241
4O
621
75O
325
15
1299
15
59
134
4
422
3481
53
187
1
3540
44,774
Mesa
County
Ditch
157
62
15
248
90
320
49
41
338
79
19
21
21
48
14
15
11
169
99
34
51
19O4
Adjacent
to
River
77
160
6
26
9
5
44
83
2107
1190
132
170
2654
108
88
3
760
67
9
722
0420
Orchard
Mesa *1
Canal
702
51
78
66
53
204
77
26
563
11
159
328
141
1652
554
144
216
654
164
89
36
4
31
4
51
10
43
20
103
132
5
, ^
*• '
462
6876
Orchard
Mesa #2
Canal
65
43
5
385
9
54
269
3
1841
355
90
28
49
18
47
22
21
17
13
22
217
37
9
9
502
4130
Redlands
Canal
124
32
3
17
18
55
407
21
1134
58
371
607
69
38
677
32
44
72
4
2
836
60
9
192
16
1230
6123
Power
Canal Total
14, 381
5,261
272
249
361
4,578
2,700
126
124 14,763
139
10 2,430
'-> 7,649
11
5" 1,091
6,962
3 9,715
143
25 2,451
531
36 6,410
8 653
40
725
19 3,806
2,273
161
19"1
5 7,144
47
213
420
21
H39
51
^ 7,684
S20
12
14
9
1 IB
5 17.329
303 123, 12P
-------
percent can actually be considered productive. In the demon-
stration area the percentages are 70 and 52, respectively. The
use of the term productive relates to the areas producing cash
crops such as corn, sugar beets, small grains, orchards, and
alfalfa.
IRRIGATION PRACTICES
The prevalent method of applying water to croplands in the
Valley is furrow irrigation. Small laterals carrying 0.03 to
0.14 cubic meters per second (1 to 5 cubic feet per second)
divert water from the company or district operated canal systems
to one or more irrigators. Water then flows into field head
ditches where it is applied to the lands to supply moisture to
the growing crops and maintain a low salinity root zone
environment in order to sustain plant growth.
The predominantly alfalfa, corn, sugar beet, orchard, and
small grain economy is served by a more than adequate water
supply. The 28,665 hectares (70,830 acres) of irrigable crop-
land encompassed within the irrigation system enjoys a total
diversion of more than 2.4 hectare-meters per hectare (8 acre-
feet per acre) during normal years. Considering that the
potential evapotranspiration of these croplands is usually less
than 0.9 hectare-meters per hectare (3 acre-feet per acre), it
is obvious that existing water use efficiencies are low. There
is no groundwater used for irrigation purposes. The abandonment
and withdrawal of farmlands for other uses has also contributed
to the surplus of water since there has been no reduction in
diversions. Most of this "excess" water is wasted into the
drains. The Grand Valley water budget and the distribution of
flows for 1968 is graphically presented in Figure 14.
Enough variation in climate exists in the Valley to separate
the agricultural land use into three primary regions. In the
eastern end of the Valley, the protective proximity to the
abrupt Grand Mesa results in extended periods of frost-free days
which allows apple, peach, and pear orchards to abound. In the
western half of the Valley, the primary emphasis is on producing
corn, alfalfa, sugar beets, and small grains. (Sug'ar beets are
presently not grown in the Valley due to the closure of the
Holly Sugar factory in the fall of 1976.) Between these two
regions is a transition zone of small farms and the urban
setting of Grand Junction, the population center of the area.
The farms in this transition area are particularly affected
by adverse soil conditions, and high salt contributions are
being returned to the Colorado River. The Grand Valley Salinity
Control Demonstration Project Area, which was illustrated in
Figures 3 and 4, was selected in this transition area. The
primary advantage for undertaking the studies in this area was
35
-------
u>
CTl
Plateau Creek Inflow
(13,800 ha -m)
Colorado River Inflow
( 297,650 ha -m)
Cropland
Precipitation
( 3,100 ha-m)
Gunnison River Inflow
( 178,000 ha-m)
Evaporation 8 Phreatophyte Use
Canal Diversions Adjacent to River ( 3,450 ha -m)
(69,000 ha-m)/ ^ Irrigation from Return Flow ( 45,100 ha-m)
Canal 8 Lateral
Seepage
(9,000 ha-m
Tailwater
SpUIs (37,000 ha-m
Net Evaporation 8
Phreatophyte
Evapotranspiration
( 8,400ha-m)
eep Percolation
(7,500 ha-m)
Cropland Evapotranspiration
( I8.60O ha-m)
Colorado River
Outflow
(462,IOOha-m)
Figure 14. Graphic representation of the magnitude and distribution of water flows in
the Grand Valley for 1968 (taken from Skogerboe and Walker, 1972).
-------
that earlier phases of the Grand Valley Salinity Control
Demonstration Project were conducted here and thus a great deal
of data was already available to facilitate this investigation.
Also, accomplishments achieved under adverse conditions can be
much more meaningful than improvements on better agricultural
lands.
Two main irrigation entities divert water from the Colorado
River. These are the Grand Valley Water Users Association
(United States Bureau of Reclamation Project) and the Grand
Valley Irrigation Company. A third irrigation company, the
Redlands Power and Water Company, diverts water from the
Gunnison River. A number of smaller companies have carriage
agreements with the two major canals for delivery of Colorado
River water. These include the Palisade Irrigation District
(Price Ditch) and the Mesa County Irrigation District (Stub
Ditch) who have such an agreement with the Grand Valley Water
Users Association (Government Highline Canal). The Grand
Valley Irrigation Company is composed of several smaller canals,
including the Mesa County Ditch, Kiefer Extension, the Independ-
ent Ranchman's, and others. The irrigation system of the Valley
is shown in Figure 15. There are about 287 kilometers of canals
in the Valley.
Canal deliveries within the system are controlled by
spillage into drains and natural washes and not by regulation
of the diversion at the river. This water contributes very
little to the salt loading, but is often 20 percent to 25 percent
of the total river diversions. If the canal systems would change
to a strict demand-type delivery system and accept more respon-
sibility for lateral water deliveries and use, the spillage
would be negligible. Such a change would entail the general
acceptance of more efficient irrigation methods such as trickle,
sprinkler, border, cut-back furrow, dead-level irrigation, tail-
water recovery systems, automation, and some change in tillage
practices. In short, this would require major local
institutional changes.
Historical irrigation development in the Grand Valley was
reported in detail in an earlier EPA report, "Evaluation of
Canal Lining for Salinity Control in Grand Valley," and only a
very brief summary will be presented here. The first large-
scale irrigation in the Valley began in 1882 with the construc-
tion of the Grand Valley Canal (now the Grand Valley Irrigation
Company), which was privately financed. Other private systems
were built during the period between 1882 and 1908 when con-
struction started on the last major system, which was the Grand
Valley Project by the United States Bureau of Reclamation
(USER). The last major construction was completed in 1926. The
Grand Valley Project consists of two divisions: The Garfield
Gravity Division and the Orchard Mesa Division on the north and
south sides of the river, respectively.
37
-------
U)
00
Scale in Miles
1012345
Scale in Kilometers
Figure 15. Grand Valley Canal Distribution System.
-------
The canals and ditches in the Grand Valley are operated and
maintained by the organizations mentioned earlier. Discharge
capacities at the head of the canals range from 20 m3/sec (700
cfs) in the Government Highline Canal to 0.8 m3/sec (30 cfs) in
the Stub Ditch and diminish along the length of each canal or
ditch. The lengths of the respective canal systems are approxi-
mately 88.5 kilometers (55 miles) for the Government Highline
Canal, 19.3 kilometers (12 miles) each for the Price, Stub, and
Redlands Ditches, 177 kilometers (110 miles) for the Grand Valley
system, and 58 kilometers (36 miles) for the Orchard Mesa
Canals. The capacities, dimensions and seepage losses of the
canals in the Valley are summarized in Table 4.
The term lateral is used in this text to refer to those
small conveyance channels which deliver water from the company
canals to the farmers' fields. These small channels usually
carry flows less than 0.14 m3/sec (5 cfs) and range in size up
to 1.2 or 1.5 meters (4 or 5 feet) of wetted perimeter. There
are more than 552 kilometers (343 miles) of laterals in the
Grand Valley as determined by the USER. Not counting the
Redlands area of the Valley, there are 1,553 laterals in the
Valley.
When water is turned into the lateral system, it becomes
the responsibility of the users entitled to the diversion and
not the ditch company. The only exception is the Government
Highline Canal which sometimes treats their larger laterals as
small canals and turnout water at headgates on these laterals.
However, no effort is made beyond the headgate.
Single users served by an individual turnout are not
uncommon, but most laterals serve several irrigators who decide
among themselves how the lateral will be operated. Most of the
multiple-user laterals, which may serve as many as 100, run
continuously throughout the irrigation season with the unused
water being diverted into the drainage channels. USER figures
show that the average irrigated acreage served by a lateral is
between 10 and 15 hectares (25 to 37 acres).
A substantial part of the project reported herein is based
on the concept of a lateral as a complete subsystem. By proper
water management and rotating large flows of water around the
entire lateral subsystem, irrigations can be much more efficient,
and no one will suffer. This is being done in other parts of
the Valley, but the cases are very few. The main reason this
is not widely practiced, as it is in many other areas of the
West, is that the Valley is very "water-rich" and has not had
to resort to large-scale water conservation measures.
Under the Stub Ditch, Price Ditch, and Government Highline
Canal (in the demonstration area), the water is allocated on a
per acre basis and can never be transferred from the land.
39
-------
TABLE 4. DIMENSIONS, CAPACITIES,
VALLEY, COLORADO
AND SEEPAGE RATES OF CANALS IN THE GRAND
Canal
Government Highline
Grand Valley
Grand Valley Mainline
Grand Valley Hiqhline
Kiefer Extension
Mesa County
.u
O Independent Ranchman's
Price
Stub
Orchard Mesa Power
Orchard Mesa^No. 1
Orchard Mesa No. 2
Redlands Power
Redlands No. 1 and No. 2
TOTAL CANALS
Length
Km
73.7
19.8
21.7
37.0
24.5
4.0
17.4
9.5
11.3
3.9
24.1
26.1
2.9
10.8
286.7
Inlet Q
m^/sec
16.99
18.41
7.08
8.50
3.96
1.13
1.98
2.83
0.85
24.07
3.02
1.98
24.07
1.70
Wetted
Perimeter
m
19.19
16.67
13.86
12.62
7.25
6.67
3.17
7.27
2.94
8.20
6.46
3.58
16.88
3.95
Days of
Operation
per Year
214
214
214
214
214
214
214
214
214
365
214
214
365
214
Effective
Seepage Rate Seepage
m3/m2 /day m3/dav
0.076
0.030
0.046
<~» f\ A f
U . U**O
0.046
0.046
0.046
0.046
0.046
0.061
0.061
0.061
0.050
0.122
77,300
10,900
10,800
22,100
6,800
600
2,600
2,200
1,400
3,300
7,400
4,800
1,900
4,200
156,300
Salt
Contribution
m. tons/yr
54,100
7,600
7,600
15,400
4,800
700
1,800
1,600
1,000
2,300
5,100
3,300
1,300
2,900
109,500
-------
The allocation is 0.5 Colorado Miners Inches (38.4 Colorado
Miners Inches (CMI) =1.0 cfs) per acre (1.0 CMl/ac =1.82
1/s/ha) and must run continuously under the by-laws of the
Palisade Irrigation District (Price Ditch) and the Mesa County
irrigation District (Stub Ditch). it should be noted that west
of the demonstration area, where the Government Highline Canal
is not serving lands under carriage contracts, the water is pro-
vided on a limited demand basis varying from 0.75 to 1.0 cfs per
40 acres (0.021 to 0.028 m3/s per 16.2 ha).
The Grand Valley Canal, the Mesa County Canal, and several
others (which are served by waters released from the Grand
Valley Canal) are entirely privately owned and have an arrange-
ment by which the water shares can be bought, sold, rented or
transferred anywhere in the entire system. One share of water
is 0.4 Colorado Miners Inches (0.30 1/s).
The common irrigation philosophy concerning water duty is 1
share (4.7 to 5.8 gpm, or 0.30 to 0.37 1/s) for one acre,
continuous flow; and this was a reasonable criterion when the
canal systems were established. For example, if a farmer had
80 (32.4 ha) acres, he had 80 shares of water, and if the total
allotment of water was rotated around the farm, the irrigations
were fairly efficient. However, since that time, average farm
units have become much smaller, and using the same criterion of
1 share per acre, the irrigations obviously had to become less
efficient. This is because smaller streams of water have slower
advance times, therefore, the opportunity time for larger
amounts of deep percolation.
Practically all irrigations in the Valley utilize open
ditches with siphon tubes on row crops with 30-inch row
spacings. On crops such as alfalfa and small grains, the irri-
gations are usually a variation of flood irrigation using
"corrugations" or shallow furrows and also using siphon tubes
or a "cut-and-dam" system with some unlined ditches. USDA-SCS
figures show that there are more than 1,640 kilometers (1,020
miles) of head ditches in the Grand Valley of which about 1,300
kilometers are unlined.
Border irrigation has not proven beneficial in the Grand
Valley due to crusting, causing germination problems. However,
very high irrigation efficiencies have been observed in the
Grand Valley borders. The USDA-ARS is presently conducting
some experiments using dead-level irrigation which is a varia-
tion of level border irrigation using furrows in an attempt to
circumvent the crusting problems.
Sprinklers have met with little success in the Grand
Valley, and local irrigators say that sprinklers cause crusting,
compaction, and erosion problems and, therefore, will not work.
This attitude is due to past experience (in the early 1950's
41
-------
when sprinklers were still new). The first sprinkler systems
which were installed in the Valley were not designed to operate
on the area soils. They generally had too high application
rates and inadequate pressures. Experience and experimentation
have shown, however, that application rates of around 5 nun/hr.
(0.20 in/hr) and nozzle pressures of 37.9 x 104 to 41.4 x 104
Newtons per square meter (55 to 60 psi) have presented none of
the aforementioned problems, but sprinklers still have not been
generally accepted. Center-pivot systems are limited in the
Valley primarily due to the small field sizes and also to
traction problems in the heavy soils. However, side-roll
sprinklers and other light, portable systems have worked quite
well. Solid-set systems, especially on orchards with frost
control capabilities, have been successful where installed, but
have also not been widely accepted. The sprinkler systems
installed by this project have been used only on established
crops such as orchards or alfalfa, and their use on annual
crops might require additional research on special management
practices such as minimum tillage. Recent studies by the USDA-
ARS in the Grand Valley with a small center-pivot on corn and
reported no significant yield increases, but the high degree of
water control was a definite advantage (Duke et al., 1976).
Economic studies are also needed considering the costs of energy
against the efficiencies obtained from other less energy-
consumptive methods.
Trickle (or drip) irrigation has likewise not been accepted
largely due to the high initial investment costs, and the water
savings are not an economic incentive. Also, present trickle
irrigation technology is essentially limited to widely spaced
perennial crops such as orchards or vineyards, and these account
for less than 10 percent of the total irrigated acreage in the
Valley. In addition, the comparable cost of sprinklers with
frost protection capabilities (which trickle irrigation systems
do not have) presents some competition to trickle irrigation.
The common philosophy regarding irrigation improvements
appears limited to concrete linings and land shaping rather
than installing more efficient and sophisticated irrigation
methods. This is due to the abundant, low-cost water. Greater
irrigation efficiencies are generally not economically
warranted. Also, this attitude is partly due to national ASCS
regulations which do not allow cost sharing for sprinklers and
gated pipe (or other types of "portable" systems).
The USDA-SCS estimates that approximately one-fifth of
the head ditches and laterals in the Grand Valley have been
lined, although some are undoubtedly in need of replacement.
Many of the irrigation leaders in the area proudly point to this
fact as a sign of local progressive irrigation practices.
42
-------
A very common and generally necessary irrigation practice
is to plant the crops and irrigate them up. Furrows are usually
on a 30-inch (76 cm) spacing and the seeds planted halfway
between two furrows. Under this practice, individual irrigation
sets often run 36 to 48 hours until the field has become
"blacked" out (until the water has completely soaked across all
the area between furrows). This first irrigation is unquestion-
ably the water application which has the largest contribution to
deep percolation and could probably be reduced by changing
tillage practices such as planting on the edge of a furrow
rather than in the center. Attempts to introduce new tillage
practices into the area have likewise met with limited success.
According to the SCS (1976), there are approximately 1,465
kilometers of tailwater ditches in the Grand Valley. The only
tailwater reuse systems in the Valley have been installed by
governmental agencies for demonstration purposes. Other than
these, the only tailwater reuse is whatever return flows enter
a canal or lateral and are used downstream. Most of the tail-
water is diverted into the large open drains which pass through
the area and is lost.
Flow measurement structures in the Valley are rare. The
SCS inventory indicated that there were 840 such devices in the
entire Valley. There were 92 total structures permanently
installed on the CSU demonstration area during the course of
the project. All but 200 of these flow measurement devices are
located under the Government Highline Canal.
SALINITY CONTRIBUTION
The Grand Valley has an estimated salinity contribution
averaging from 600,000 to 900,000 metric tons of salt annually
to the Colorado River. The majority of these salts are a direct
result of the deep percolation from irrigated farmlands and
water seeping from unlined canal and lateral water delivery
systems. Examination of district and canal records show that
this contribution has been fairly constant over the past sixty
years.
The introduction of water from these surface sources
dissolves the salt contained in the saline soils and marine
shales of the area. When the water reaches the shallow ground-
water reservoir, the slight hydraulic gradient causes some
groundwater to be displaced into the river. This displaced
water has usually had sufficient time to reach chemical equilib-
rium with the salt concentration in the shale and/or cobble
aquifer (approximately 8,700 mg/1).
The water from seepage and deep percolation tend to reach
chemical saturation with the very abundant soluble gypsum and
calcite that are present in the soils and geologic substrata.
43
-------
The concentration of salts appears to be controlled by geologic
conditions and is independent of seepage rates. The salt con-
tributed by concentration effects and residual salts in the
soils is relatively minor and the salt loading from tailwater
runoff is almost negligible.
If the amount of groundwater is reduced through water
management and canal and lateral linings, the concentrations of
other salts such as sodium chloride will rise slightly, but not
enough to compensate for the reduction in flows. Therefore,
the net contribution to salt loading is essentially directly
proportional to the reduction in groundwater flows.
The Grand Valley is the most significant agricultural con-
tributor of salinity on a per acre basis in the entire Colorado
River Basin. This factor makes the Grand Valley an important
study area. Consequently, the results of research and imple-
menting salinity control measures will have a greater impact on
salt load reduction in the Colorado River. Also, the conditions
encountered in the area are common to many locations in the
basin.
44
-------
SECTION 5
GRAND VALLEY SALINITY CONTROL DEMONSTRATION PROJECT
GENERAL DESCRIPTION
The study area used for demonstrating the Implementation of
Agricultural Salinity Control Technology in Grand Valley was
illustrated in Figures 3 and 4. This area is one of the most
salt affected areas in the Grand Valley, and it was the site of
the earlier projects on salinity control beginning in 1968. This
area, therefore, had a great deal of historical data available
to facilitate this investigation.
The demonstration area is characteristically operated by
small unit farmers, and since the soils are severely affected by
the high water table conditions, agricultural productivity is not
presently sufficient to support most of the occupants. The major-
ity of persons living in the area have outside jobs in local
businesses and industries. In the past few years, the area has
been subjected to rapid urban development. Some of the water-
logging and salinity problems, which are evident in the area, are
illustrated in Figure 16.
These lands were once among the most productive in the Grand
Valley (in the early 1900's), and a very significant impetus
could be generated locally in support of salinity control pro-
grams if the demonstrated measures continue to be effective in
returning these lands to a higher level of agricultural produc-
tivity. A soils map of the demonstration area can be seen in
Figure 17. (A guide to the soil symbols was presented in Table
2.) A typical geologic cross-section of the demonstration area
is presented in Figure 18.
An additional advantage of this location was that a majority
of the irrigation companies in the Valley are involved in the
demonstration area, thereby facilitating both the cooperation of
the irrigation companies and the application of project results
to other parts of the Valley.
45
-------
a. An example of waterlogging problem on
the tight clay soils of the Grand Valley.
b. Salinity accumulations on the surface of
this field have forced it out of produc-
tion (lateral GV 160).
Figure IS. Waterlogging and salinity problems in Grand Valley,
46
-------
Grand Valley Canal
Scale I Milt
Note- Refer to Table 2 for Listing of Soil Classification
'Stub Ditch
Government
Highline Canal
Price Ditch
Figure 17.
Soil classification map of the Grand Valley Salinity Control
Demonstration Project.
-------
Legend
Fine Grovel
o
o
3
IB
3
'.'v •:•'.•':;:.: :-j| Silty Clay Loom Soils
Cobble Aquifer
N-
to
c
| | Tight Cloy (Discontinuous)
tHHHHj Moncos Shale Bedrock
00
Orchard
Mesa
-o
Scalt I Milt
Horizontal Scolt
Figure 18. Typical geologic cross-section through the demonstration area,
-------
INSTRUMENTATION
The instrumentation in the study area indicated by Figure
19 provided valuable data concerning many of the important water
and salt movements. This same instrumentation has been utilized
since 1968 when the first project was initiated. Figure 20 illus-
trates some of the procedures used to install and to collect the
monitoring system data.
While some of the parameters were measured directly (i.e.,
drainage discharges, lateral diversions, water quality, precipi-
tation and other climatic data), others were investigated indi-
rectly. The parameters related to groundwater movement were
monitored by using piezometers, wells, and soils analysis.
Because so many of the water and salt subsystems cannot be
evaluated directly by feasible methods, peripheral investigations
were made in which a portion of the area is examined in detail
for reactions to changes in other parts of the flow phases. Such
studies included: farm efficiency studies indicating the rela-
tive proportion of evapotranspiration, deep percolation, and soil
moisture storage; cylinder infiltration tests to indicate various
hydraulic properties of the soil; land use investigations which
yielded the respective vegetative uses of the area; soil sampling
which when analyzed in the laboratory yielded information on soil
moisture, salt movements, and assisted in irrigation scheduling;
and others pertaining to specific parameters of crop, water, and
salt subsystems.
From 1968 through 1976, along the lower edge of the demon-
stration area, a network of wells and piezometers were maintained
to monitor the groundwater flows out of the area to the river.
Weekly water samples were taken and elevations were recorded.
Several large interceptor drains carry some groundwater and tail-
water out of the area to the river. These drains had flow meas-
urement devices with recorders and measurements were taken
throughout the year. While these data can only directly indicate
the trends and average data for the entire area, these data can
be used in conjunction with the verified hydro-salinity model of
the demonstration area and the results of other concurrent
research.
HYDROLOGY
Walker (1970) defined the base hydrology for the project
area for 1969. The water and salt inflows to the project hydro-
logic area are tabulated in Tables 5 and 6, respectively. These
data were formulated from individual measurements.undertaken
during the first phase of the salinity control studies in the
demonstration area.
49
-------
Ul
o
• Piezometers
• 2" Wells
»Cond Rating Section
® Drainage Measurement
Drains
Area Boundary
Stub Ditch
Scale I Kilometer
Scale I Mile
Government
Highline
Canal
Price Ditch
Mesa
County
Ditch
and Valley Canal
River
Figure 19. Location of hydrologic measurement points in the Grand Valley
Salinity Control Demonstration Project Area.
-------
a. Installation of piezometers with
a jetting rig by project personnel
b. A Cutthroat flume installed in a large
open drain with a continuous water
level recorder to monitor tailwater
and drainage flows.
Figure 20. Installation of monitoring network.
51
-------
10
TABLE 5. WATER BUDGET INFLOWS TO THE DEMONSTRATION AREA, IN HECTARE-METERS
(WALKER, 1970)
Precipitation
Month
Oct.
Nov.
Dec.
Jan.
Feb.
March
April
May
June
July
Aug.
Sept.
ANNUAL
cropland
24.7
16.0
16.0
16.0
22.2
22.2
22.2
16.0
16.0
16.0
29.6
24.7
241.6
phreat.
4.9
3.7
3.7
3.7
4.9
4.9
4.9
4.9
4.9
4.9
6.2
4.9
56.5
Canal Diversions
Seepage
14.8
0
0
0
0
0
14.8
14.8
14.8
14.8
14.8
14.8
103.6
spillage
148.0
0
0
0
0
0
246.6
246.6
246.6
246.6
246.6
246.6
1627.6
lateral
diversions
252.8
0
0
0
0
0
360.0
480.9
556.1
591.8
543.8
397.0
3182.4
Lateral Diversions
seepage
9.9
0
0
0
0
0
14.8
14.8
14.8
14.8
14.8
14.8
98.7
tailwater
148.0
0
0
0
0
0
120.8
197.3
197.3
197.3
185.0
185.0
1230.7
root zone
diversions
94.9
0
0
0
0
0
224.4
268.8
344.0
379.8
344.0
197.3
1853.2
-------
Of particular interest in Table 5 is that of the quantity of
water diverted into the lateral system. Thirty-nine percent
results in field tailwater, 58 percent of the water reaches the
root zone, of which only about half of this water can be utilized
by the plants, and a significant portion is thereby lost to deep
percolation.
Water flows through the main delivery system from east to
west and the field slopes are from north to south. The laterals
run north to south on a grade which ranges from 0.2 percent to
1 percent and unlined channels are often deeply eroded.
TABLE 6. SALT BUDGET INFLOWS TO THE DEMONSTRATION
AREA IN METRIC TONS OF TOTAL DISSOLVED
SOLIDS (WALKER, 1970)
Canal
Month
Oct.
Nov.
Dec .
Jan.
Feb.
March
April
May
June
July
Aug.
Sept.
ANNUAL
seepage
99
0
0
0
0
0
145
145
145
99
99
99
834
.8
.2
.2
.2
.8
.8
.8
.8
salt diversions
lat.
spillage div.
1714
0
0
0
0
0
2467
2467
2467
1723
1723
1723
14288
.6
.6
.6
.6
.7
.7
.7
.5
1769.
0
0
0
0
0
3628.
4808.
5561.
4145.
3810.
2785.
26508.
0
8
2
1
9
2
1
3
Lateral
seepage
63.6
0
0
0
0
0
145.1
145.1
145.1
99.8
99.8
99.8
798.3
salt diversions
root zone
tailwater diversions
1034
0
0
0
0
0
1215
1968
1977
1388
1306
1306
10196
.2
.6
.6
.7
.0
.4
.4
.9
671
0
0
0
0
0
2268
2694
3438
2658
2404
1378
15513
.3
.0
.4
.3
.1
.1
.9
.1
Water and salt flows occurring beneath the soil surface in
the project area are tabulated in Tables 7 and 8. The subsurface
flows were calculated from the information obtained on the sur-
face flows.
Comparison of the measured drainage outflows and the ground-
water outflows for 1969 indicate that the drains in the study
area carry approximately 27 percent of the total groundwater out-
flows, while only 22 percent of the total flow in the drains are
groundwater flow. In addition, of the 1853.2 ha-m (15,030 acre-
feet) reaching the root zone from irrigation plus 202.2 ha-m
(1,640 acre-feet) from canal and lateral seepage, and 1096.1 ha-m
53
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TABLE 7. WATER BUDGET GROUNDWATER FLOWS TO THE DEMON-
STRATION AREA IN HECTARE-METERS (WALKER,1970)
Root zone
Diversions
Month
Oct.
Nov.
Dec .
Jan .
Feb.
March
April
May
June
July
Aug.
Sept.
ANNUAL
cropland
use
56.7
16. 1
8.6
0
0
0
83.8
113.4
205.9
246.6
224.4
140.6
1096.1
deep
perc.
62.9
0
7.4
16.0
22.2
22.2
162.7
171 .4
154.1
149.2
149.2
81.4
998.7
Groundwater
drainage
flows
24.7
22.2
18.5
14.8
8.6
7.4
37.0
37.0
37.0
37.0
30.8
61.6
336.6
phreat .
use
24.7
4.9
3.7
3.7
4.9
4.9
37.0
38.2
40.7
43.1
49.3
34.5
289.6
flows
storage
change;
-12.3
-69.1
-49.3
-37.0
-24.7
-24.7
74.0
66.6
37.0
24.7
24.7
-12.3
-2.4
subsur.
outflow
55.5
45.6
38.2
38.2
38.2
39.5
49.3
64.1
74.0
78.9
80.2
69.1
670.8
(8,890 acre-feet) were consumed by evapotranspiration. The net
result being that only 56 percent of the deep percolation and
seepage losses are returned to the river.
Analysis of the results of salt budgeting indicated that for
each metric tons of total dissolved solids applied to the root
zone, approximately 3.2 metric tons exit through the groundwater
channels.
PREVIOUS IMPROVEMENTS IN THE DEMONSTRATION AREA
In 1967, the irrigation companies of the Grand Valley began
to be aware of the potential financial burden which could be
placed upon the Valley's water users by salinity damages down-
stream, especially if they were forced to comply with salinity
control measures at their own expense. Consequently, efforts
were begun to initiate action based on the concept that abatement
of the salinity problem would have state, regional, national, and
international benefits. Furthermore, it was claimed "that devel-
opment of irrigation within the Grand Valley was done without
intent of damage to others, and was done within existing laws and
regulations enacted after the fact." With this in mind, the
54
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U1
TABLE 8. SALT BUDGET GROUNDWATER SALT FLOWS IN THE DEMONSTRATION AREA
METRIC TONS OF TOTAL DISSOLVED SOLIDS (WALKER, 1970)
IN
Root Zone Salt
Month
Oct.
Nov.
Dec.
Jan.
Feb.
March
April
May
June
July
Aug.
Sept.
ANNUAL
salt
depository
571.5
172.4
108.9
36.3
45.4
45.4
1206.6
1515.0
2467.6
2032.1
1914.2
1224.7
11340.1
accumulated
storage
0
172.41
0
0
0
0
0
0
0
0
0
0
172.4
Budget
pickup
3728.6
4508.fi
3347.6
3456.4
3302.2
3519.9
3837.5
3728.6
3111.7
2821.4
3674.2
3801.2
42838.1
Groundwater Salt Budget
salt add.
to G.W.
671.3
0
281.2
36.3
45.4
45.4
2268.0
2694.4
3438.3
2658.1
2404.1
1378.9
15921.4
total salt
added
834.6
0
281.2
36.3
45.4
45.4
2558.3
2984.7
3728.6
3764.9
2603.7
1578.5
18461.6
drainage
salt
1233.8
1152.1
1097.7
961.6
607.8
526.2
2404.1
2222.6
2032.1
1850.7
1542.2
1233.8
16864.7
salt storage
change
-743.9
-5089.4
-3265.9
-2449.4
-1769.0
-1896.0
1814. 41
1814. 41
2404. I1
1478. 71
1478. 71
-734.8
-6958.1
salt
outflow
3329.4
3356.6
2531.1
2531.1
2739.7
3039.1
3991.7
4490.6
4808.2
4735.6
4735.6
4145.9
44434.6
storage change from irrigation, not groundwater outflow.
-------
irrigation companies formed a cooperative organization called the
Grand Valley Water Purification Project, Inc. and petitioned the
Federal Water Quality Administration for 70 percent to 30 percent
matching funds on demonstrating canal lining as a salinity con-
trol measure. This money was forthcoming, and in 1968 the Agri-
cultural Engineering Department of Colorado State University was
contracted to perform the technical evaluation regarding the
effectiveness of canal lining in reducing the Grand Valley's
salt load to the Colorado River.
The particular demonstration area was selected because it
contained lands served by the majority of irrigation companies
in the Valley, and their cooperation after the project would be
needed to implement the proposed changes on a valley-wide scale.
After completion of this initial project, the canal companies
reorganized into the Grand Valley Canal Systems, Inc. and remain-
ed active. Presently, their main purpose is to collectively
represent the irrigation interests of the valley.
Canal and Lateral Lining
As part of this investigation, three areas were studied in
the Grand Valley, one of which is the present demonstration area.
The initial phase of the project involved the determination of
the seepage rates from the canals and laterals in the three test
areas. The ponding technique was employed to assure reliability
of the results. Figure 21 shows some of the structures and data
collection.
The lengths evaluated included a 4.2 kilometer (2.6 mile)
section of Stub Ditch, 3.2 kilometers (2 miles) of Government
Highline Canal, 3.1 kilometers (1.9 miles) of Price Ditch, and
3.5 kilometers (2.2 miles) of Mesa County Ditch. In addition,
the tests were made along the 0.8 kilometer (0.5 mile) length of
the Redlands First Lift Canal. A 0.24 kilometer (0.15 mile)
length of Grand Valley Canal was not evaluated because of the
evidently high seepage losses. A summary of the test results is
shown in Table 9, indicating only moderate seepage rates in most
canals and a relatively high rate in the Redlands First Lift
Canal. The average seepage rates were approximately 0.05 m-Vday
(cmd) (0.15 ft3/ft2/day (cfd)) in the Stub, Price, and Mesa County
ditches; 0.08 cmd (0.25 cfd) in the Government Highline Canal?
and an average rate of 0.12 cmd (0.40 cfd in the Redlands First
Lift Canal.
The lining of the Government Highline Canal (Grand Valley
Project) was done with gunite (which is a mixture of cement, sand,
and water pneumatically applied to a wire mesh, also called shot-
crete) on the downhill bank of the last mile through the study
area. This was done to evaluate the effectiveness of downhill
linings in reaches where the canal is located directly in the
shale formation. The Stub Ditch linings consisted of the standard
56
-------
a. Waterlevel data collection
before lining;
b.
Ponding test and meas-
urement station on an
unlined section of a
canal;
c. Measurement station for a
ponding test after lining;
d. Project personnel col-
lecting water level
data on a lined section
of a canal.
Figure 21. Canal ponding tests by project personnel
57
-------
TABLE 9. COMPARISON OF SEEPAGE RATES BEFORE AND AFTER CANAL
LINING USING PONDING TESTS
Canal
Seepage rate
before lining
(cfd)1 (cmd)*
Seepage rate
after lining
(cfd)1 (cmd)2
Reduction
Stub Ditch
Price Ditch
Gov't Highline Canal
Mesa County Ditch
Redlands First Lift
Canal
0.15
0.15
0.25
0.15
0.40
0.05
0.05
0.08
0.05
0.12
0.07
0.07
0.13
0.03
0.06
0.02
0.02
0.04
0.01
0.02
46.6%
46.6%
49.0%
76.0%
84.0%
Icfd = cubic feet per day.
2cmd = cubic meters per day.
concrete trapezoidal slip form lining. The linings in the Price
Ditch and the Redlands First Lift Canal were also concrete trape-
zoidal slip form, but larger than the Stub Ditch lining. The Mesa
County Ditch in the demonstration area was lined completely with
a gunite process. The Grand Valley Canal also has a short section
lined by the gunite process. Figure 22 shows some of the finished
linings. Figure 23 illustrates the location of the canal linings
done in the demonstration area. Table 10 presents the summary of
the total canal lining improvements.
The USDA-ARS, under contract to the United States Bureau of
Reclamation in 1974-1975, made ponding tests on the major canals
and laterals at other locations in the Valley, which resulted in
close agreement with the values found in the demonstration area.
The results of the seepage rate measurements for nine lateral
sections are tabulated in Table 11. The wetted perimeter of the
laterals which were lined ranged between 3 and 5 feet (0.9 to 1.5
meters) and were characterized by large amounts of grass and
weeds growing in the channel. The capacity of the laterals was
usually between one-half and 5 cubic feet per second (0.01 to
0.14 cubic meters per second), and, in most cases, some problems
with erosion have occurred as a result of the fairly steep grade.
Some lengths throughout the area had already been lined, but
these did not represent a significant portion of the total lateral
lengths.
Numerous evaluations of seepage rates in the laterals located
in the demonstration area were conducted as part of those earlier
studies. The inflow-outflow method was used in these determina-
tions. A typical loss rate of 0.003 m3/s (0.1 cfs) per mile is
representative of a usual lateral, or about 0.15 cmd (0.5 cfd).
Based upon before and after ponding tests upon the small canals,
the lining of most laterals would result in about an 80 to 90
percent seepage rate reduction.
58
-------
a. Lining on the Price Ditch;
b. Lining on the Stub Ditch;
Figure 22. Photographs of the canal lining program.
59
-------
c. A canal before lining; and
Figure 22 (continued). Photographs of the canal lining program.
60
-------
Legend
•••••••• Gunite Lining, Downhill
Bank Only
'" Concrete Slip-form
Lining
—— " " Gunite Lining
" Unlined Sections
Open Drains
Stub Ditch
Government
Highline
Conol *"""-
Scale I Mile
Figure 23. Location and type of canal linings constructed in the demonstration area.
-------
TABLE 10. CANAL LIMING IMPROVEMENTS SUMMARY
Map Desig- Company Name
nation Canal Name
Area I
A
B
C
D
E
(Demonstration Area)
Grand Vaiiey irrigation Co.
Mesa County Canal
Palisades Irrigation Co.
Price Ditch
Grand Valley Water Users
Assn.1 - Gov't Highline Canal
Mesa County Irrigation Co.
Stub Ditch
Grand Junction Drainage Dist.
Open Drains
Closed Drains
Laterals
Type of Length
Lining (Km)
Gunite
Slip Form
Gunite
Slip Form
Slip Form
Tile
Slip Form
3.5
3.1
1.6
4.0
Area II
Grand Valley Irrigation Co. 1
Grand Valley Canal
Gunite
0.24
Area III
Redlands Water and Power
First Lift Canal
Slip Form
0.8
1 Downhill bank lining only.
62
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TABLE 11. RESULTS OF EARLIER CSU (1959-1970) LATERAL LOSS INVESTIGATIONS
Canal
Name
PD
GV
MC
Gate
No.
166
164
151
95
100
110
120
46
70
Study lenqth
(Ft.) (m)
2175
3620
1667
4910
2970
5000
5280
2600
3540
662.
1103.
50fl.
1496.
905.
1524.
1609.
292.
1079.
9
4
1
6
3
0
0
5
0
Length loss Length loss
(cfs) (mVs) (%)
0.030
0.097
0.048
0.034
0.020
0.590
0.030
0.00
0.99
0.00085
0.00275
0.00136
0.00096
0.00057
0.01671
0.00085
0.00000
0.02R04
3 .
3.
7.
1 .
2.
12.
1.
0.
18.
8
6
4
5
6
3
0
0
0
Loss per mile Loss per mile
(%) (cfs) (m3/s)
9.
5.
23.
1.
4.
13.
1.
0.
26.
11
27
46
61
62
0
0
0
82
0.073
0.114
0.152
0.037
0.315
0.623
0.030
0.00
1.50
0.0021
0.0032
0.0043
0.0010
0.0089
0.0176
0.0085
0.0000
0.0425
Design
Discharge1
(cfs) (ni^/s)
1.00
2.50
i.UO
2.00
1.00
5.00
3.50
3.00
6.00
0.0283
0.0708
0.0263
0.0566
0.0283
0.1416
0.0991
0.0850
0.1699
This value is inlet capacity
along a length.
consequently thp design would need to be altered as diversions are made
-------
A summary of the lateral linings constructed as part of this
project is included in Table 12. Even though only a small frac-
tion of the total lateral system has been improved, the linings
resulted in a seepage reduction on the order of 12.3 to 24.6
hectare-meters (100 to 200 acre-feet) annually. It should be
noted that the bulk of the linings were constructed above the
Grand Valley Canal where water tables are relatively deep, and
thus experience somewhat higher seepage rates than would be en-
countered in areas where water tables are higher.
TABLE 12. SUMMARY OF THE SIZES AND LENGTHS OF
LATERALS LINED DURING THE EARLIER
YEARS (1969 AND 1970) OF THE PROJECT
Description
14" trapezoidal (35.56 cm)
12" trapezoidal (30.48 cm)
10" trapezoidal (25.40 cm)
6" x 10" rectangular (15.25cm x 25.4cm)
12" x 10" rectangular (30.48cm x 25.4cm)
12" diameter buried pipe (30.48 cm)
8" diameter buried pipe- (20.32 cm)
6" diameter buried pipe (15.25 cm)
TOTAL
Length
Feet
5,941
11,435
624
1 1,478
1 1,987
978
2,111
950
25,504
or
4.83 miles
Meters
1,810.8
3,485.4
190.2
450.5
605.6
298.1
643.4
289.6
7,773.6
or
7.77 km
1-First dimension listed in description refers to the bottom
width.
The benefits accrued from lining the lateral system in an area
like the Grand Valley are essentially the same as described ear-
lier concerning the canal linings. Because of the vast extent
(length) of the lateral system, the effect of the laterals is
much greater than the canals. As with the canal system, the
appurtenances, such as the control and measurements structures,
are an integral part of any lateral system improvements. The
benefits derived from more efficient water management (measure-
ment and control) cannot be ignored.
The results of this study indicated that canal and lateral
lining in the test area reduced salt inflows to the Colorado
River by about 4,260 metric tons (4,700 tons) annually. The bulk
of this reduction is attributable to the canal linings, but
clearly indicated is the greater importance of lateral linings.
The length of laterals (600 kilometers), plus the head ditches
(1,640 kilometers), is about eight times greater than the length
64
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of canals (286 kilometers) in the Valley. The economic benefits
to the Lower Basin water users alone exceeded the costs ($350,000
construction plus $70,000 administration) of this project. It
was concluded that conveyance lining in areas such as the Grand
Valley, where salt loadings reach 18 metric tons or more per
hectare) are a feasible salinity control measure. The local
benefits accrued from reduced maintenance, improved land value,
and other factors add to the feasibility of conveyance linings
as a salinity management alternative.
Irrigation Scheduling
As a result of recommendations on the canal lining project,
an irrigation scheduling project was initiated (1972) in the
demonstration area as a salinity control measure. Since a large
fraction of the water passing through the local soils returns to
the river as deep percolation resulting from overirrigation,
measures aimed at improving irrigation efficiencies promise a
high potential for controlling salinity. Among all the methods
for achieving higher water use efficiencies on the farm, "scien-
tific" irrigation scheduling is one of the most promising and
least expensive.
Irrigation scheduling consists of two primary components:
crop evapotranspiration calculated by using climatic data, and
soil characteristics. First of all, the field capacity and the
permanent wilting point for the particular soils in any field
must be determined. And, more importantly, infiltration charac-
teristics of the soils must be measured. Only by knowing how
soil intake rates change with time during a single irrigation,
as well as throughout the irrigation season, can meaningful pre-
dictions be made of: (a) the proper quantity of water which should
be delivered at the farm inlet for each irrigation; and (b) the
effect of modifying deep percolation losses. With good climatic
data and meaningful soils data, accurate predictions of the next
irrigation date, and the quantity of irrigation water to De
applied can be made. In order to enable the "rxgator to apply
the proper quantity of water, a flow measurement structure is
absolutely required at the farm outlet.
Excessive water supplies, the ne^ss"? *?fsfeh^a local ?esis-
irrigation system (particularly the laterals, ,eandalocalert ^^
65
-------
more responsibility for lateral deliveries and changing to a
demand type system.
Some problems have been encountered involving poor communi-
cation between farmer and scheduler, as well as certain deficien-
cies in the scheduling programs dealing with evapotranspiration
and soil moisture predictions. Correcting these conditions is
easily rectified and will make irrigation scheduling much more
effective and acceptable locally. y
Water budgets were obtained from intensive investiaation on
two local farms. The selection of the two study rlrms was intend-
ed to be representative of conditions valley-wide Salvsis of
the budgets reveal that approximately 50 percent of S water
applied to the fields came during the April and May period when
less than 20 percent of the field evapotranspiration potential
had been experienced. Salt pickup estimates during this earlv
part of the season amounted to about 60 percent of th£ *nn^T
total for each field (Figure 24). These^esuJts have been veri-
fied in subsequent investigations in the study areas?
Another indication of the importance of MVI,, o
"
V,, o
management is presented in an analysis irriaion
As the season progressed, the soils became less ver
the crop water use increased, causing marked fL?
irrigation efficiency. Thus,' if irrigation scheduling3
employed in its optimal format, salt pickuS fSSS ! 1S
can be reduced as much as 50 percent or mSL ^hi^n^
is explained in detail in Section 9. S Phenomenon
The results of this demonstration proiect sho™
gation scheduling is a necessary, but not sufficient
achieving improved irrigation efficiencies ThP !£ i f°K f°r
in reducing the salt pickup caused by overirria^fo strides
from the employment of scientific irrigation JS J ?-Wl11 Come
junction with improved on-farm irrigation ^acSces * ^ C°n"
The project was conducted in cooperation w-n-v, 4-u
USER irrigation scheduling program in the vSllpJ the existing
1976, the USER worked with the Grand Vallev r* %' Durin*«« nal Iinin9s
in this initial project to tile some open dra?n4°0° was sPent
slip form some other open drains. Thi<* wa«, 5 and concrete
s was done to correct two
66
-------
100
May
Jim Jul Aug
Irrigation Season
Sept
Figure 24. Seasonal distribution of salt pickup from the farms in the test area
(Skogerboe et al. , 1974a).
-------
small surface problems in the area. The field data indicated
that most of the open drains in the area were performing as
intended and were not seeping water back into the groundwater.
However, there still existed a need to evaluate the effective-
ness of field drainage as a salinity control measure, and this
was undertaken in 1972.
Drainage investigations in the Grand Valley began shortly
after the turn of this century when local orchards began failing
due to saline high water tables. Studies showed the soils to be
not only saline but also to have low permeabilities.
At that time, the future development of the Bureau of
Reclamation's "Grand Valley Project" loomed as a severe threat
to the low lying lands between it and the Colorado River. In
answer to these apparent drainage needs, the necessary solutions
were clearly set forth but never fully implemented because of
the large capital investment required. However, the citizens of
Grand Valley did elect to form a drainage district supported by
a mill tax levy in order to construct open ditch drains and
some buried tile drains to correct local trouble spots. All of
these efforts barely contained the rise in water tables, and
today more than fifty years later, the local conditions remain
essentially unchanged.
The construction of open drains has played an important
role in Grand Valley. These drains serve as outlets for the tile
interceptor drainage systems. They also intercept and convey
tailwater runoff which would otherwise flow over surface lands,
infiltrate, and contribute to additional subsurface groundwater
flows, subsequently reaching the Colorado River with increased
salt pickup.
This study was undertaken with the history of local
drainage in mind, but for a different purpose, which was to skim
water from the top of the water table before it reaches chemical
equilibrium with the highly saline soils and groundwater in the
cobble aquifer; and, to demonstrate to local farmers the
benefits in increased crop production by improved field drainage,
which results in lower soil salinity levels by permitting more
effective leaching.
Three farms were selected for field drainage investigations
during the 1972 irrigation season. The studies showed that the
drainage problems on two of the farms could be alleviated by
improved on-farm water management practices. In particular,
increasing irrigation efficiency during the early part of the
season would sufficiently reduce deep percolation losses, which
in turn would keep the groundwater level at a satisfactory depth
below the ground surface to allow good crop production.
68
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The results from the two farms illustrate the adage— "an
ounce of prevention is worth a pound of cure." Thus, the first
steps in a salinity control program are to minimize: (a) seepage
losses from canals and laterals; and (b) deep percolation losses
from croplands (ideally, the deep percolation losses would not
exceed the leaching requirement) . By minimizing the amount of
moisture reaching the groundwater, the requirements for field
drainage will also be minimized.
The third farm had been originally selected for investiga-
tion as an example of one of the worst conditions encountered in
the Grand Valley. A 4.7 hectare (11.6 acre) field on this farm
was selected for construction of a relief field drainage system.
Besides having a very high groundwater level, the soils had low
permeability, high salt content (with a high sodium content) ,
and the topography was irregular. in order to correct these
deficiencies, the following measures were taken: (a) a drainage
system consisting of 3,353 meters (11,000 linear feet) of 10.2
cm (4-inch) diameter perforated, corrugated polyethylene plastic
SiE?HWa? ^n^talled on 12-2 nwter (40-foot) centers at an average
depth of 1.8 meters (6 feet); (b) the field was leveled to per-
?i mSre^ni*°?n surface irrigation; (c) the field was plowed
™* M?PS? °J- ?.°m (2 feet) to increase surface permeability;
and (d) the field was planted in salt tolerant Jose Tall
Wheatgrass with a cover crop of oats.
Studies of the three farms, plus two additional farms
investigated for irrigation scheduling, show that the field
,
heJ £nt%had * salinitv Averaging 3,000 mg/1 less than
the Present subsurface irrigation return flows reaching the
Colorado River.
A principal advantage of field drainage (i.e., tile or
perforated pipe) is that the effluent is a point source which
can then be placed into a collection system for disposal (i.e.,
evaporation ponds, deep well injection, or desalination). Field
drainage and the collection of drainage effluents from the open
drains in conjunction with salt disposal would be required to
achieve a zero discharge policy for subsurface irrigation return
tiows. However, field drainage on a large scale would probably
be one of the last salinity control measures to be implemented
due to its very large initial costs.
As part of this study, an alternative use of drainage was
considered. During the 1950 's pump drainage offered no salinity
control benefits because the salinity of the pump drainage
effluent is comparable to the salinity of subsurface irrigation
return flows reaching the Colorado River. A network involving
pump drainage in combination with desalination would be very
effective in reducing salt loads returned to the river. In
determining the costs of pump drainage in combination with
desalting, it becomes apparent that this alternative is quite
69
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costly (about $310 per metric tons of salt removed). However,
with the recent advances in desalination technology, this alter-
native method of decreasing salt loads of river systems is
certain to become increasingly feasible as time progresses.
This control measure would likely be considered as the final
step in an overall salinity control program, which would only
be taken at some time in the future.
In viewing the results of this study, it is obvious that
field drainage is a curative rather than preventative measure.
High costs of such programs illustrate the need of first mini-
mizing the flows passing through the root zone or seeping from
canals and laterals. The small amount of water entering the
groundwater could then be effectively removed by drainage
systems and/or wells located at selected locations. Thus, field
drainage as it pertains to objectives of salinity control is a
remedy which must be considered but will probably not be
implemented.
70
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SECTION 6
PROJECT INITIATION
LATERAL SELECTION
Since this study involved the selection of several laterals
in which the irrigators to be served would participate by con-
tributing to the construction costs, total cooperation was imoer-
ative. By first publicly advertising the project, and then per-
sonally contacting one or more parties who seemed most interested,
about eleven potential groups in the project area were identified.
After the prople had discussed the matter among themselves, pro-
ject personnel arranged meetings where the specific details of
the project were outlined and questions answered. Since the
average size farm in the area is about 2 to 6 hectares (5 to 15
« ?ni' t;e4_num^er of People involved could possibly be as high
Jn<- °' +. S Uali?' 89 Persons were involved. Interestingly, the
anticipated problems of coordinating such a large group did not
Jllcl L." i 1 cl J. 12 G •
,*•,* ThLgrfnt award for this Project was received February 18,
1974 The first step in the lateral selection process began five
days later when an announcement of this new project along with
a location map was placed in the local'newspaper (Figure 25).
The article stated the funding available, its purposes and condi-
tions for qualifying, and the availability of project representa-
tives at an open house to be held February 27, 1974, at the local
Holiday Inn to answer further questions. The response to the
newspaper article was such that at least 40 individuals represent-
ing 15 laterals responded (only 10 of which were actually in the
demonstration area) and further field contact was not necessary.
The overwhelming response at this open house resulted in consider-
able time being saved and undoubtedly ranks as one of the most
important events leading to the project's success.
At the open house, each inquirer was advised that the best
action at the time would be to contact others on the lateral,
briefly explain the project objectives, and enlist support. On
March 18, 1974, contact with the individuals who came to the open
house was reestablished and meetings were scheduled over the next
two weeks. With the exception of two cases, the meetings were
unqualified successes in gaining the acceptance of the people
involved. Lateral groups accepting the project were told final
71
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$230,000 EPA grant to fund
new seepage control pro/ecf
Funding has been received from the
U.S. Environmental Protection
Agency to construct irrigation im-
provements in the area between Grand
Junction and Clifton, according to the
Agricultural Engineering Dept. at
Colorado State University.
The area is the same that received
funding five years ago for concrete and
gunnite lining of canals and laterals to
reduce seepage.
CSU officials said the advantage in
continuing work in the area is that
much is already known about the
underground water and the salt
flowing into the Colorado River from
the area. Additionally, they said,
considerable money has been spent on
both equipment and personnel for
instrumenting the particular
demonstration area.
The amount of information provides
a strong basis for evaluating the ef-
fectiveness of irrigation im-
provements in reducing river salinity.
The study area was originally
selected because it is fairly
representative of the Grand Valley.
Five canals traverse the area, thereby
allowing greater participation by the
majority of irrigation entities in the
valley.
The EPA has granted $230,000 for the
lining of laterals, construction of new
on-farm irrigation systems, and in-
stallation of tile drainage
The funds can be used to pay 70 per
cent of the construction costs, with the
farmer paying the remaining 30 per
cent.
The demonstration project will use
two laterals under each of the five
canals in the study area. Laterals will
be selected to represent a wide variety
of conditions.
To participate, all of the irrigators
under a lateral must be willing to
share in the costs of lateral lining and
on-farm irrigation improvements. A
few of the laterals ha .re already been
extensively lined with concrete under
the previous demonstration project
CSU officials said the selection of a
lateral and all the crop land served by
a lateral, rather than an individual
farm, has a tremendous advantage in
allowing control at the lateral turnout.
Thus both the quantity of flow and the
time of water delivery can be con-
trolled, thereby providing improved
water management and higher crop
yields.
The new construction program will
be explained by CSU personnel at the
Holiday Inn from 9 a.m. to 4:30 p.m.
Feb. 27. Any irrigator having lands in
the study area can inquire at that time
about possibilities for participating.
The new study will use a variety of
irrigation methods, including "tuning
up" methods presently in use CSU
said considerable experience has been
gained in improving the existing
irrigation methods while evaluating
irrigation scheduling as a salinity
control measure in the Grand Valley.
However, more advanced irrigation
methods have not been evaluated in
the Grand Valley for salinity benefits
Irrigation systems to be constructed
under the new project include
automated farm head ditches, border
irrigation, sprinkler irrigation, and
trickle irrigation. Tile drainage also
will be constructed on some farms.
In particular, some of the lands near
the Colorado River will require
drainage facilities to reclaim them for
high level productivity.
CSU officials said the most
significant aspect of the project is use
of a salinity control "package"' rather
than a single control measure.
Field days will be conducted in the
third year - 1978 — of the project.
probably during August.
Figure 25.
Announcement of grant award in Daily Sentinel
(Grand Junction, Colorado) February 23, 1974.
72
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site selection would not be made until the fall or winter of 1974-
1975 so that each lateral could be evaluated for its usefulness
in satisfying the project objectives. Also, this time could be
used by irrigators to finalize their own willingness to be includ-
ed in the project and to reach agreement among themselves concern-
ing such matters as cost sharing and the desirable operating
characteristics of the improved irrigation systems.
The project was established on the basis that the project
would pay 70 percent and the participants 30 percent of the total
construction costs, not including engineering or administration
costs. The 30 percent matching requirement could be paid in cash
or by equal value arrangements such as direct labor, equipment
rentals, land leveling costs, or through the voluntary assistance
of local organizations such as the Grand Junction Drainage
District.
As more was learned about the various lateral systems and
the attitudes of the irrigators, it was necessary to continually
reevaluate the group of laterals in terms of project objectives.
In addition, throughout the first year, project personnel received
numerous requests (at least two to three every week during the
summer months of 1974) from other interested landowners within
the project area. In fact, requests were still being received
after completion of the project.
The selection of a lateral as a subsystem, rather than an
individual farm, has the advantage of maintaining control at the
lateral turnout. In this way, both the quantity of flow and the
time of water delivery can be controlled, thereby facilitating
improved water management throughout the subsystem. The lands
selected demonstrated a wide variety of irrigation and drainage
problems which provided a representative cross-section of the
irrigated lands of the Valley. With the available knowledge
regarding the study area, a lateral and the associated lands
served by the lateral could be used as a logical subsystem for
evaluating the salinity reduction in the Colorado River resulting
from the implementation of a salinity control technology package.
The laterals selected were evaluated on the basis of four
broad criteria:
1) In a lateral system, 100 percent participation must be
obtained from all the water users on lands served by
this lateral;
2)
The degree of anticipated participation in all of the
three phases of the project, which are the preevalu-
ation, construction, and postevaluatioa covering the
anticipated three-year period of the project;
73
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3) The type and extent of irrigation and drainage problems
represented, and the different solutions and alterna-
tives which were agreeable and economically advantageous
to the landowners; and
4) The analysis of the least cost expenditures, demonstra-
tion value to other farms, and maximum production of
research results in order to realize project objectives.
One hundred percent participation was required to accomplish
one of the major goals of the project, which was to demonstrate
the effectiveness of a "package" of technological improvements
on a broad scale for purposes of salinity control. Numerous
lateral group meetings and individual discussions with irrigators
were used to evaluate, as objectively as possible, the anticipated
degree of voluntary participation in the projects three phases,
as well as their willingness to change existing irrigation prac-
tices and methods. This was very critical since many of the pro-
posed systems would often be designed in such a way that a return
to old methods would practically be impossible, and the new pro-
posed management methods might be mandatory for continued opera-
tion of the system. The results and implications were fully
explained to all the participants before any final decisions were
mutually agreed upon.
The type of physical problems and the extent of these prob-
lems were carefully examined by project personnel to insure that
unnecessary duplication did not occur and that as many different
problems as possible could be treated by as many methods as pos-
sible. The long-range objectives of agricultural salinity control
in the Grand Valley and the Colorado River Basin were also taken
into account in choosing the type of problems to be studied, and
alternative control measures to be implemented.
The mix of various salinity control technologies were care-
fully matched to achieve a maximum research effect on each lateral
subsystem. The types of planned treatments included sprinkler
irrigation, drip irrigation, concrete lateral linings, concrete
head ditches, gated pipe, automated cut-back furrow irrigation,
land shaping and clearing, flow measurement, tailwater removal
systems, buried PVC plastic irrigation pipelines, agricultural
field drainage, irrigation scheduling, and various improved water
management practices for each subsystem. In some cases, only
increased labor spent on irrigation, in conjunction with one
other type of treatment, was incorporated into the experimental
design.
Once the selected laterals were identified by their special
problems, the alternative solutions to alleviating these problems
were presented to the landowners and a proposed course of action
was planned out in complete accordance with the wishes of all
parties. Project personnel then analyzed the costs of the
74
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various alternatives and prepared preliminary cost estimates.
Further meetings were held with the water users under each lateral
and final plans were mutually adopted. Any other information
necessary for the preparation of the final bid documents to com-
ply with the landowners' wishes was then collected.
LATERAL LAND USE
In order to determine the potential consumptive use and to
provide information for irrigation scheduling and land use change
comparisons, the land use of each lateral was mapped each year.
It should be stated that no attempt was made by project personnel
to influence the landowners as to the land use and crops grown on
these fields. The land use under each lateral during the project
period is summarized in Table 13.
An examination of the lateral land use data indicates that
the improvements (which were essentially completed prior to the
1975 season) caused several changes in land use. For example,
there was a 45 percent reduction in idle and abandoned farmlands
which were put into production. In addition, some abandoned farm-
land was cleared of phreatophytes in preparation for returning
such land to agricultural production.
The net decline in total potentially irrigable cropland was
due to the withdrawal of land for the construction of a school,
industrial uses, and farmstead improvements.
LATERAL HYDROLOGY
At the beginning of the 1974 irrigation season, the basis
hydrologic elements under each of the selected laterals were
monitored. At the canal turnout to each lateral, a flow measur-
ing flume and a continuous water level recorder were installed
to provide readings on the diversions into each subsystem. A
summary of these data for the 1974 irrigation season is given in
Table 14. A network of flumes were installed in selected loca-
tions to identify tailwater and wastewater flow quantities.
Several series of shallow observation wells were installed to
observe groundwater elevations and to delineate areas in need of
special field drainage. These wells were monitored throughout
the project to indicate the effectiveness of the various
improvements.
Much of the flow measurement was changed for the 1975 and
1976 irrigation season as the individual laterals were constructed.
Some flumes were replaced with propeller meters (in the case of
pipelines), and others were switched to standardized concrete
Cutthroat flumes. In fact, the only lateral measurement
75
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TABLE 13. LAND USE DATA FOR THE LATERAL SYSTEMS FOR THE PROJECT PERIOD, IN HECTARES
LATERAL
Land Use HL C HL E
Classification 1974 1975 1976 1974 1975 1976
Irrigated Cropland
Corn 5.5 6.7 7.7
Truck Crop
Barley 0.8 0.8 0.8
Oats 2 . 4
Wheat
Alfalfa 2.4 1.0 1.0
Grass Hay 1.5
Pasture 0.9 4.2 3.0 3.0
Orchard 0.4 0.4 0.4 23.5 23.5 23.5
Idle 7.9 7.9 7.9
Other
-J SUBTOTAL 11.5 11.5 11.5 34.2 34.2 34.2
Other Land Use
Farmsteads 1.6 1.6 1.6 1.7 1.7 1.7
Urban
Stock Yards
School Yards
SUBTOTAL 1.6 1.6 1.6 1.7 1.7 1.7
Industrical
Miscellaneous
SUBTOTAL
Phreatophytes
Salt Cedar
Greasewood
SUBTOTAL
TOTAL 13.1 13.1 13.1 35.9 35.9 35.9
I D
E
N T
I
F T
PD 177
1974
O.
3.
1.
1.
1.
3.
9.
1.
22.
2.
2.
2
5
8
8
2
5
2
5
7
3
4
4.7
0.4
0.4
27.8
1975
0.
0.
3.
0.
1.
2.
1.
3.
7.
1.
22.
2.
2.
5
2
5
3
8
4
2
5
8
5
7
3
4
4.7
0.4
0.4
27.8
197
0.
3.
2.
1.
3.
8.
1.
21.
2.
3.
CATION
GV 92
6 1974 1975 1976
11.5 11.5
2
5
7
2 8.9 8.9 8.5
5
7
5 1.9
3 20.4 20.4 10.4
,3 3.9 3.9 3.8
8
10.1
6.1 3.9 3.9 13.9
0
0
2V
.4
.4
.8 24.3 24.3 24.3
1974
16.
0.
6.
2.
11.
1.
14.
0.
15.
9
5
9
5
5
,9
,0
,5
.9
70.6
5
1
1
8
79
.6
.6
.3
.5
.1
GV 95
1975
17.6
0.5
2.5
16.9
11.5
1.9
9.8
0.5
8.6
69.8
5.6
2.4
1.3
9.3
79.1
1976
13.
3.
2J.
10.
1.
9.
0.
7.
69.
U
U
3
5
9
8
5
,8
.8
5.6
2
1
9
79
.4
.3
.3
.1
1 hectare - 2.47 acres
(Table 13 continued on following page)
-------
TABLE 13 (CONTINUED) . LAND USE DATA FOR THE LATERAL SYSTEMS FOR THE PROJECT PERIOD, IN HECTARES1
LATERAL
Land Use
Classification
1974
GV 160
1975
1976 1974
MC 3
I D E N T
1975 1976 1974
MC 10
1975
IFICATION
1976
MC 30
1974 1975 1976 1974
TOTAL
1975
1976
Irrigated Cropland
^i
Corn
Truck Crop
Barley
Oats
Wheat
Alfalfa
Grass Hay
Pasture
Orchard
Idle
Other
SUBTOTAL
0.3
1.0
1.9
13.4
12.3
24.6
53.5
2.1
0.3
1.9
14.4
19.9
14.9
53.5
2.1
0.3
1.3
1.9
14.4
21.7 0.4
9.7 2.6
51.4 3.0
2
0
1
4
3
0.4 0.4 12
0
2.6 2.6 17
3.0 3.0 41
.0
.5
.1
.5
.1
.2
.4
.8
.6
7.4
0.5
3.8
11.4
5.7
0.6
7.0
7.8
44.2
5.1
0.5
10.3
9.6
3.3
0.6
7.7
7.1
44.2
35.4
1.5
11.2
4.6
1.8
7.4 7.4 7.4 28. i
6.4 6.4 6.4 26.3
54.1
28.3
78.0
1.5
13.8 13.8 13.8 271.3
45.8
1.5
10.6
31.0
1.8
29.9
23.3
50.2
27.4
49.6
1.5
273.1
27.9
1.0
17.6
34.2
28.2
23.3
52.3
27.9
43.8
3.4
259.6
Other Land Use
Farmsteads
Urban
Stock Yards
School Yards
SUBTOTAL
9.3
3.3
0.5
13.1
9.3
3.3
0.5
13.1
9.3 0.7
3.3
0.5
13.1 0.7
0.7 0.7 6.
1.
0.7 0.7 7.
.4
.1
,5
6.4
1.1
7.5
6.4
1.1
7.5
0.3 0.3 0.3 31.8
5.7
3.2
1.3
0.3 0.3 0.3 42.0
31.8
5.7
4.0
1.3
42.8
31.7
7.1
4.0
11.4
54.2
Industrial
Mis ce 1 laneous
SUBTOTAL
2.1
2.1
0.4
0.4
0.4
0.4
2.5
2.5
Phreatophytes
Salt Cedar
Greasewood
SUBTOTAL
TOTAL
3.6
8.5
12.1
78.7
3.6
8.5
12.1
78.7
3.6
8.5
12.1
78.7 3.7
4.
4.
3.7 3.7 54.
9
9
0
2.3
2.3
54.0
2.3
2.3
54.0
8.5
3.5
17.0
14.1 14.1 14.1 330.7
5.9
8.5
14.4
330.7
5.9
8.5
14.4
330.7
1 hectare = 2.47 acres
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TABLE 14. ANNUAL LATERAL DIVERSIONS IN HECTARE-METERS
Year
Lateral
HL C
HL E
PD 177
GV 92
GV 95
GV 160
MC 3
MC 10
MC 30
Total
1974
6.31
58. 182
96.14
69.67
132.96
80.82
3
76.30
30.70
551.08
1975
1
33.73
41.88
1
132.65
36.95
3
79.98
31.57
356.76
1976
20.31
82.50
60.47
52.65
109.43
177.32
3
90.75
36.15
629.58
^Sprinkler system only
Not in operation
structures which remained unchanged were some selected tailwater
measurement stations.
Construction of the laterals also added a large number of
flow measurement structures within the lateral subsystems. Flow
measurement was available after each grower received his water.
This permitted a high degree of monitoring capability, as well
as a much higher level of water management on the individual
farms.
During the first irrigation season (1974), a large amount
of effort was made to collect the design data which would be
needed for the construction of lateral improvements in 1975.
This included surveying all the laterals to obtain slopes and
distances, and in some cases, topographic surveys were made on
selected fields. The "legal" water rights as compared to the
actual water deliveries (which were measured) were determined by
examining the records of the canal companies and by meeting with
canal officials. Seepage losses in the laterals were measured
in selected cases by measuring the inflow and outflow of a specif-
ic length of lateral. Reaches had to be over 610 meters (2,000
78
-------
to minimize the effect of flow measurement errors
the measured difference, which was the seepage loss.
r tonestablish manY of the parameters of on-farm
, a large amount of data was collected throughout the
6"^16' land US6 maS
doesh nnuay
to establish consumptive use amounts and assist in irri-
™C dUll?gZ • Exhaustive rin
-------
Soil sampling by project
personnel, this same instru-
ment was also used to in-
stall observation wells on
field drainage installations;
'
. ^-»->w
b. Preparing for infiltration
tests;
c. Running advance recession tests by
project personnel;
Figure 26. Data collection activities by project personnel.
80
-------
"
d. Depicts water sampling
activities in drains;
V >
e. Depicts flow measurement
in open drains; and
f. Depicts lateral flow
monitoring activities
Figure 26. (Continued).
81
-------
SECTION 7
DESIGN, CONSTRUCTION AND OPERATION OF IMPROVEMENTS
DESIGN
Design Philosophy
All of the improvements were organized into a logical exper-
imental design in order to effectively evaluate the objectives
of the project. An overall design philosophy was formulated to
govern the general designs of improvements within the lateral
subsystems. The first major consideration was the placement of
flow measurement devices in each lateral subsystem. These meas-
urement structures were placed immediately below the lateral
headgates, at all flow divisions and after each farm delivery
point on the main delivery system. The grower knew how much
water he had by the difference between his and his neighbors'
flow readings. All measurement devices could be read directly
without the use of tables or any calculations. To accomplish
this, propeller meters read in cubic feet per second (cfs),
totalized in acre feet; and special enameled metal staff gauges
were designed, manufactured, and placed in all the Cutthroat
flumes (Figure 27) which read directly in cfs and Colorado Miner's
Inches. Two sizes of Cutthroat flumes were standardized through-
out the project: 1) a 20.3 cm throat width by 91 cm length (8-
inch throat width by 3-foot length); and 2) a 7.6 cm throat width
by 91 cm length (3-inch throat width by 3-foot length). Examples
of these flumes in operation are shown in Figure 28.
Another consideration was the grade for all pipelines and
concrete ditches would be governed by the general slope of the
land surfaces as much as possible. This reduced costs consider-
ably because it eliminated many costly drop structures and energy
dissipation facilities. Where possible, the improvements would
follow the old channels and an attempt was made to consolidate
ditches and laterals to minimize the duplication of facilities.
Efforts were also made to incorporate surrounding lands under
one lateral in order to maximize the usefulness of the
improvements.
All conveyance systems were designed for approximately 200
percent of the water rights. This was done for three main rea-
sons: (a) under the Grand Valley Canal, water rights can be sold,
82
-------
Figure 27.
8 Inch By 3 Foot
Cutthroat Flume
Colo. Miners
Inches cfs
-200.0
o 5-°*
- 175.0 4.5.
-150.0 4><>
3.5-
- 125.0
3.0-
2.5-
- 75.0 2.0-
O
1.5-
- 50.0
- 40.0 | 0,
- 30.0
~ 20.0 0.5.
0.4-
- 10.0 °*3~
0.2-
- 5.0
O.I-
O
• i.o
3 Inch By 3 Foot
Cutthroat Flume
Colo. Miners
Inches cfs
0 2.0 -
•70 0
1.75-
I C —
I.O -
— 50.0
1.25-
1.0 •
0.9 -
-30.0 °'8 "
o °-7 '
0.6 -
-20-° 0.5 -
0.4 -
0.3 -
-10.0
0.2 -
- 5.0
O.I -
0.05-
- 1.0
O
Scale
1 cm = 2. 52cm
Staff gauges for 8-inch by 3-foot and a 3-inch by
3-foot Cutthroat flumes (can be read directly in
either Colorado Miner's Inches or in cubic feet per
second).
83
-------
a. Precast Cutthroat flume being installed;
•
Cutthroat flume in opera-
tion in a lateral;
r
c. Close-up of special staff
gauge in operation.
Figure 28. Cutthroat flume installation and operation,
84
-------
bouqht, rented or transferred anywhere in the system and new
water might come into the systems at any time; (b) the canal com-
panies customarily divert what they estimate as at least 120 per-
cent of the water rights into the lateral subsystem (often much
more); and (c) the majority of the subsystems collect tailwater
for reuse from other laterals. Designing for roughly 200 percent
of water rights actually added very little to the costs of the
systems due to standard material size availability.
If a lateral passed through a subdivision or other urban
type area, the water was conveyed in a closed conduit for health
and safety reasons, for the aesthetics of eliminating an open
ditch, and to minimize debris problems caused by children playing
in the ditches. Under roadways and access routes, the PVC plastic
irrigation pipes were encased with concrete pipe. If a corrugated
metal pipe (CMP) culvert needed to be replaced or relocated, it
was replaced with a high sulfate-resistant concrete pipe. The
concrete pipe was about one-half the material cost of CMP, but
the initial installation costs were higher. In the highly saline
soil conditions of the Grand Valley, the concrete would be expect-
ed to outlast the CMP by at least 20 years. When water was
taken from a lateral to irrigate ornamental lawns and shrubs in
a subdivision, the subdivision water was separated from the
agricultural water because the methods of operation are so dif-
ferent as to be incompatible with one another.
General Design Procedures
The first step in the collection of design and preevalu-
ation information was to meet with the farmers and to walk the
individual laterals with aerial photos and obtain the following
information: lateral boundaries, exact locations of existing
ditches, individual crop types, crop row spacing, planting dates,
irrigation methods, number of sets per irrigation, all places
where tailwater enters the system, all places where tailwater
leaves the system, and whether it is reused or is lost. The
identification of all potential problem areas such as road cross-
ings with dimensions, division boxes and associated structures,
deep erosion areas requiring fill, trees to be removed, fences,
locations of buried utilities, and locations and sizes of exist-
ing special hydraulic structures such as siphons and flow meas-
urement structures were also noted for future reference.
Project personnel then surveyed all the preselected laterals
to determine pertinent information including the slopes and
lengths of various reaches, cross-sections and profiles of the
laterals, field sizes, run lengths, field slopes, and, in some
cases, the topography of the individual fields. Some of the
data collection activities are depicted in Figure 29.
After evaluating the local topography and location of exist-
ing structures, the hydraulic computations necessary to insure
85
-------
a. Project personnel surveying a lateral.
b. Project personnel discussing suggested
improvements.
Figure 29. Collection of lateral design information.
86
-------
proper performance of the proposed individual components were
made. The siting and/or relocation of structures was also
considered at this time.
IMPROVING OPERATIONAL CHARACTERISTICS OF THE LATERAL SUBSYSTEMS
As various elements of the lateral subsystem were completed,
project personnel operated and tested the facilities to compare
the actual performance with the designed capabilities, and also
to locate possible construction problems and other potential
troubles. As could be expected, some problems did arise, but,
for the most part, were easily corrected. These systems have
worked quite well and, as planned, the greatly increased system
flexibility in the selected systems permits a much higher degree
of water management than was previously possible. Also, in
several cases, the improved water management and irrigation
scheduling have resulted in higher crop yields. Some operational
characteristics, which may not have been mentioned in preceding
sections of this report, are included in the following discussion.
Personal Aspects of Improving Lateral Operations
On every lateral there was one person who accepted the
responsibility of organizing the lateral for the project; and
as part of the original project goals, it was hoped that indi-
viduals on each lateral would take responsibility for water man-
agement operation of the lateral subsystems. However, in all
cases, project personnel had to assume the responsibility because
no one on the lateral would do so. Persons on the lateral real-
ized the emotional nature of water rights and use, and justifi-
ably did not want the headaches and problems associated with
water management on a lateral scale. The lateral water users
are presently content to try to work out future water distribu-
tion and use on a case-by-case, person-to-person relationship.
Where project personnel managed the water distribution, it was
accepted without question since they were considered "neutral,"
and they had a large amount of credibility with the water users.
An educational problem which seemed to exist on almost all
the laterals was that even though the systems were substantially
modified, there was still a considerable amount of maintenance
required. However, it was a different type of maintenance and
was often neglected in the beginning. A big job for project
personnel was to make sure that all persons knew how to maintain
the system and had a regular maintenance schedule. This was
especially important in pipeline installations which had to be
flushed on a regular basis due to sediment accumulations.
87
-------
CONSTRUCTION AND OPERATION OF LATERAL IMPROVEMENTS
The construction was completed in three stages: in the fall
of 1974, in the spring of 1975, and in the fall of 1975. There
was a small amount done in the spring of 1976 for a few additions
and changes which were necessary. The majority of the construc-
tion was completed by the start of the 1975 irrigation season.
Based upon the designs and a complete list of materials, contrac-
tor and materials' specifications were prepared in the fall of
1974. Bids were let as necessary by Colorado State University
under its format as prescribed by state law, and all low bids
were accepted. Written approval from the Project Officer was
requested and received. A summary of each lateral's improvements
is presented in the following sections.
Lateral HL C
There are 13.1 hectares (32.4 acres) which could be served
by this lateral, but at this time only 2.7 hectares (6.5 acres)
are actually presently productive. The remainder was once a
productive orchard but is now idle. The improvements made on
this lateral included the tiling of a large open drain bisecting
the 2.7 hectare field (Figure 30) and three flow measurement
devices: two 6-inch Parshall flumes and one 90 degree V-notch
weir.
This lateral lies directly under the Government Highline
Canal, and through this section the canal is cut into a Mancos
shale outcropping and, as a result, has a substantial amount of
seepage. There are several large open drains in this area to
intercept these saline seepage flows. One such drain traversed
the 2.7 hectare field making two small, nonregular shaped fields.
The large open-interceptor drain was tiled in cooperation
with the Grand Junction Drainage District who installed the tile
after the project purchased all materials necessary for the job
(Figure 31).
Tiling the large open-interceptor drain greatly improved the
irrigation and farming efficiencies of this field. Formation of
one regularly shaped field from two irregular and hard to irri-
gate fields has greatly reduced the labor requirements and im-
proved the ease of irrigation. In addition, significant increases
in yields have been reported.
Irrigations on the 2.7 hectare (6.5 acre) field were in
strict accordance with the recommended irrigation scheduling
program. The owner was very willing to follow all suggestions
as to time duration of sets and the quantities of water to be
applied. This was the only traditionally irrigated field where
this was the case.
88
-------
y 244m
/Tiled 20cm dio.
F 1/2 Road I
/Interceptor Drain
/ 2.2 hectares
Legend
Drainage Ditch
Road
Canal
Field Boundary
Tiled Interceptor
Drain
100
Scale in meten
0 200
Scale in feet
400
I
Figure 30.
Map of Lateral HL C shows improvements and field
locations.
89
-------
I
a. Drain before construction; and
Covered drain at completion of con-
struction.
Figure 31. Tiling of the large open drain on Lateral HL C.
90
-------
The irrigations were from an earthen ditch using siphon tubes,
and the proposed irrigation procedures did require more labor per
set than had been used before the improvements. However, the
total amount of labor for irrigating the entire field was still
considerably less than before because of the more efficient field
unit and elimination of 225 meters of additional head ditches.
Lateral HL E
The HL E lateral (designated HL E because it is the lateral
served by turnout gate E on the Highline Canal) contains more
than 23.5 hectares (58 acres) of orchards (apples, pears, and
peaches). The major work on this lateral, summarized by Figure
32, consisted of the installation of overhead sprinklers on 5.2
hectares (12.8 acres) of pear orchard and installation of 329
meters (1,080 feet) of 20 cm (8-inch) diameter PVC plastic irri-
gation line across a corn field to replace an old collapsed pipe-
line. After installation of the sprinkler system, 183 meters of
20 cm diameter (600 feet of 8-inch diameter) concrete tile were
installed on this lateral (in cooperation with the Grand Junction
Drainage District) as a new interceptor drain. The upper portion
of the orchard (under the sprinkler system) had suffered from a
high-water table due to canal seepage and overirrigation on the
upslope lands. The interceptor drain empties into a 25 cm (10-
inch) PVC buried plastic irrigation pipeline which was installed
for tailwater recovery and removal. The 402 meters (1,320 feet)
of pipe were installed in an old unlined tailwater ditch carrying
water from lands above the lateral. This ditch flows continuously
for the entire irrigation system. The interceptor drain will be
maintained by the Grand Junction Drainage District.
The sprinkler system can be used for frost protection (Fig-
ure 33) in the early spring, for cooling in the hot summer, and,
of course, for normal irrigations. The sprinkler installation
and materials cost $3,335 per hectare ($1,390 per acre). Oper-
ation and maintenance costs have been less than $180/hectare
($75/acre) per year. Data were collected on other parts of the
orchard in order to compare the traditional irrigation methods
against the overhead sprinkler irrigation system.
The average precipitation rate of the sprinkler system is
3.23 mm/hr (0.127 in/hr) and the risers are 4.6 meters (15 feet)
above the ground surface on an 18.3 meter x 18.3 meter (60 x 60
foot) triangular pattern. Overall sprinkler system uniformity
is described by a linear uniformity coefficient (UCL) of 86.3
percent (Karmeli, 1977), a Christiansen's uniformity coefficient
(UCC) of 89.0 percent (Christiansen, 1942), and an Hawaiian Sugar
Planters Association uniformity coefficient (UCH) of 88.5 percent
(Hart, 1961). Water is delivered to a sump (50.5 1/s or 800 gpm)
by a previously existing concrete ditch system (part of which
was lined in the earlier studies) and is then pressurized by a
50-hp electric pump.
91
-------
Highline Canal
30cm,73m
Concrete ( Pre-project)
30cm,201m
(Previous Project)
20cm,I98m
F 1/2 Road
JL
100
o
o
o
it
'•
Seal* in meters
0 200 400
i i i
Scale in feel
Legend
Drainage Ditch
Road
Canal
Buried Pipeline
Sprinkler Irrigation
Field Drainage
Concrete Ditch
Tiled Interceptor
Dram
F Road
Figure 32. Map of lateral and on-farm improvements under the
HL E lateral system.
92
-------
a. Sprinkler in operation during a freeze
period in 1976; and
b. Sprinklers in operation
for irrigation.
Figure 33. Overhead sprinklers on Lateral HL E
93
-------
The sprinkler applications are measured by a 15 cm (6-inch)
propeller meter in the pipeline. The 20 cm (8-inch) PVC plastic
irrigation pipeline has a 20 cm (8-inch) meter to record the flow,
Two 8 inch x 3 foot (20.3 cm x 91 cm) Cutthroat flumes were also
installed to measure the water applied to the rest of the orchard.
An electric-powered, self-cleaning trash removal screen (3.2 mm
or 1/8 inch-mesh) was installed immediately upstream from the
pump to remove debris from the water to prevent the sprinkler
heads from becoming plugged.
The overall benefits from the overhead sprinkler irrigation
system are quite numerous. The irrigations are very efficient
since there is no surface runoff? deep percolation is minimized;
and the entire 5.2 meters (12.8 acres) can be irrigated in one
setting. Crop cooling for high fruit quality is another economic
benefit of this system. The frost protection aspect of this
sprinkler system is a rewarding side benefit and is the main
reason that sprinkler irrigation was acceptable to this water
user. In addition, the sprinklers are air pollution free and
have larger energy savings when compared with oil, propane, or
natural gas frost protection systems.
Research on frost control by means of sprinklers has been
carried on for almost fifty years. Initial adoption of the con-
cept has been slow due to large initial investments, but it is
becoming more widely accepted because of technical or economic
disadvantages of wind machines or heaters. The theory of sprin-
kling for frost protection is that water releases heating as it
freezes (79.7 cal/gm or 144 BTU's/lb of water) and this helps
to keep the part of the plant covered by ice at approximately 0
degrees C (32 degrees F), even when the air is as cold as -9.5
degrees C to -7.8 degrees C (15 to 18 degrees F). On the other
hand, melting ice requires heat and, with sprinklers, this heat
can be supplied by the applied water rather than by the plant.
The system should remain in operation until all the ice has
melted because most frost damage occurs during the thawing stages
due to the extraction of moisture and heat from the plant cells
resulting in cell breakdown. Sprinkling for frost protection
requires that the plant be kept continually wet to maintain
plants at a minimum temperature of 0 degrees C (32 degrees F).
The degree of protection is directly proportional to the amount
and frequency of water applied. The entire area should be
irrigated in one set.
Researchers at Utah State University have recently success-
fully demonstrated that overhead sprinklers can delay fruit bud
development and thereby greatly reduce early spring freeze dam-
age to fruit trees. This procedure utilizes the sprinklers to
provide evaporative cooling during warm periods in February and
March to decrease the energy available for growth. This process
will usually delay budding (bloom) from ten days to two weeks
and eliminate about 80 percent of the possible freeze damage.
Under present canal operating procedures in the Grand Valley,
this type of frost protection cannot be practiced because the
94
-------
water is not turned into the canals until the first of April at
the earliest.
Salinity benefits of this type of sprinkler irrigation are
very evident in the great reduction of deep percolation. Under
the traditional surface irrigation methods, the deep percolation
was quite substantial (runs were 396 meters or 1,300 feet). This
salinity control measure offers a large per acre salinity reduc-
tion, is economically advantageous to the fruit farmers, and is
economically justifiable even if only for the frost control
aspects. It is estimated that a grower in the Grand Valley
annually has a 60 percent probability of a "total wipe out" with
peaches (the major fruit crop in the area), 20 percent for apples
and pears, and 80 percent for apricots due to freeze conditions
without any frost protection such as heaters, smudge pots or
sprinklers. With special tree training (i.e., pruning) practices,
almost any variety of fruit can use overtree sprinklers for frost
protection, although much caution should be used with "stone"
fruits (i.e., peaches, apricots) due to their inability to support
ice loadings. The orchards of the Valley have been going out of
production for several years, and this type of irrigation with
frost control offers great potential to assist the ailing fruit
industry of the Grand Valley. For example, during the spring of
1976, this section of the orchard was saved due to the frost pro-
tection provided by the sprinkler system (Figure 33). The rest
of the orchard was virtually frozen out with 22 degrees F (-5.6
degrees C) low temperature and had very little production. The
1976 frost wiped out about 30 percent of the total fruit crop in
the Grand Valley. Approximately 30 percent of the Valley fruit
crop was also lost in 1975 due to frost damage.
The 5.2 hectare orchard was carefully scheduled for irriga-
tions. The soil moisture was monitored by a system of probes
and tensiometers. The owner-operator of this farm is one of the
most progressive farmers in the Grand Valley and was very willing
to follow the scheduling and operational recommendations made by
project personnel.
The 390 meter (1,280 feet) 20 cm (8-inch) diameter PVC plas-
tic irrigation piepline which was installed to replace an old
pipeline permitted farming operations directly over the pipeline,
achieved essentially zero seepage, and provided a much greater
degree of control over the water. The increased farming effi-
ciency was an extra benefit and, at the same time, greatly
reduced ditch maintenance.
Lateral PD 177
Work on the 27.8 hectare (68 acres) of lateral PD 177 con-
sisted of the installation of 2,051 meters (6,729 feet) of buried
plastic pipeline distribution system with 230 meters (760 feet)
of concrete lining and installation of two drip irrigation
95
-------
systems on 2.2 hectares (5.4 acres) of peaches and apples. An
illustrative summary of the PD 177 improvements is shown in
Figure 34.
The installation of pipelines was done completely by irri-
gators on the lateral. The Mesa County Road Department installed
the necessary new culverts under the roads after all materials
and engineering were provided by the project. The delivery sys-
tem above this lateral is a concrete ditch and buried pipeline
arrangement constructed under the previous lining study (298
meters of 30.5 cm diameter concrete pipe and 793 meters of 30 cm
x 30 cm trapezoidal concrete lining). The amount of work under-
taken by the farmers themselves has been significant. Many per-
sons donated their own time and equipment for the installation.
The irrigators have a very good understanding of the system
operation as a direct result of their work on the construction
(Figures 35 and 36).
The drip irrigation systems (Figure 36) were initially in-
stalled on 1.5 hectares (3.4 acres) of young peaches. Later, a
second system was installed on 0.7 hectares (1.6 acres) of mature
apples. This will eventually cover another 3 hectares (7.2 acres)
of apples. Drip irrigation is a recent development in irrigation
which is gaining wide acceptance in many water short areas of the
world. Water is applied directly at the plant via an "emitter"
which drips water onto the soil at a very slow rate (4 to 8 liters
per hour). Irrigations are on an almost daily basis to replace
only the amount of water which the plants have used. The root
zone is not used as a water reservoir as in other, more tradi-
tional, types of irrigation. There is virtually no deep perco-
lation, and total water use requirements are usually one-third
to one-half of the more conventional irrigation methods practiced
in the area. An additional benefit of drip irrigation is that
plant growth is usually much more rapid than with other irriga-
tion methods, and in perennial crops, such as orchards, young
trees will often start production much sooner (i.e., one or two
years sooner) than trees grown under traditional methods. This
is because the crops are never "stressed" for water; and fertil-
izers and pesticides can be applied directly through the system.
Water measurement on the lateral is accomplished by 14 flow
measurement devices; propeller meters, Cutthroat and Parshall
flumes, and a 90 degree V-notch weir. Other installations in-
clude a self-cleaning, water-powered trash screen (6.3 mm or 1/4
inch mesh) at the entrance of the pipeline to minimize trash and
debris problems (Figure 35) and 207 meters (680 feet) of 15 cm
(6-inch) gated pipe on approximately 2.4 hectares (10 acres).
Before the project, the eastern side of Lateral PD 177 had
extreme difficulty in maintaining a dependable water supply
during the irrigation season. Since implementation of the proj-
ect, however, there has been no difficulty experienced. Ditch
seepage has been eliminated, and the operation of the lateral
96
-------
F Road
- Field Boundary
Concrete Ditch
Buried Pipeline
Gated Pipe
Trickle
20cm, Him/'25cm ,184m
I5cm ,55m ]]
(Moved from "
Set to Set)
Figure 34.
late? al System
°n~farm improvements under PD 177
97
-------
Section of lateral prior
to improvements
Cooperators installing
pipeline on lateral;
c. A water powered self-
cleaning trash screen
installed upstream of
pipeline;
d. Section of lateral after
installation of the pipe-
line with the valve box
and meter box shown.
Figure 35. Construction of Lateral PD 177
98
-------
a. Cooperator installing
water supply line for
a drip system;
b. Drip lateral placement
beside a young peach tree;
c. View of young peach orchard with
laterals in place.
Figure 36. Drip irrigation on Lateral PD 177.
99
-------
has changed quite substantially as the participants gained con-
fidence in their system. For instance, irrigators who had his-
torically diverted water continually, and had conveyed the water
directly to a waste ditch if they were not using it, have now
stopped this practice and are leaving the water in the system.
Due to the bylaws of the Palisade Irrigation Company (Price
Ditch), the system operates on a continuous flow basis. The
excess water runs directly into the major canal running below the
lateral and is reused. The irrigators are now confident that
their water will be there when it is needed.
Another major change in the operation of this lateral is
that the small subdivision at the west end of the system was, in
effect, isolated from the agricultural portion of the system.
The pipeline system was designed so that the agricultural users
would not be disturbed by erratic urban uses. Urban use of irri-
gation water can be very sporadic since the urban people have
outside employment and only irrigate their lawns ana gardens for
short periods in the evenings and on the weekends. This can be
very disruptive to an agricultural user who relies on a constant
nonfluctuating stream of water for the duration of his
irrigation sets.
The farm-urban arrangement has greatly benefited the urban
users, too, by providing a constant, dependable flow of water for
their use. They are able to irrigate with very little water
fluctuations and do not have to be concerned about damaging a
pump due to a sudden lack of water. The urban users have had to
change to a very informal scheduling arrangement since there is
not enough water for everyone to irrigate their landscapes at
one time, but this has worked out quite well. This type of water
delivery system could have considerable water savings with the
incorporation of a small reservoir at the head of a subdivision.
Since landscapes are only watered for a couple of hours each day,
much of the water passes through the subdivision without use and
is lost to the system (although it is reused by other laterals),
and a small holding pond to store this water for later use when
needed could greatly increase the distribution efficiency.
Installation of drip irrigation systems on two small or-
chards drastically changed the operational characteristics of both
orchards. Project personnel, as well as the landowner, have
learned much from the operation of these systems. High frequency
irrigations, wetting patterns, and nutrient balances using daily
irrigations have presented many new concepts and challenges.
However, the problems have been successfully dealt with, and the
advantages for salinity control are tremendous.
Gated pipe was used to subdivide some very long runs with
nonuniform slopes on another orchard under this lateral, result-
ing in much more efficient irrigations. The addition of a water-
powered, self-cleaning trash screen at the head of the system
100
-------
was of great assistance in reducing trash and plugging problems
for both siphon tubes and gated pipe, as well as the propeller
meters.
Lateral GV 92
This lateral (Figure 37) was the last lateral in which con-
struction of improvements was undertaken. The construction was
completed in the spring of 1976. Approximately half of the land
originally under this lateral was consolidated into another lateral
.(GV 95) to minimize the duplication of ditches and facilities.
in fact, almost all of the tailwater from this lateral flows into
the GV 95 system and is reused.
The system installed on this lateral is a concrete ditch
(Figure 38) and pipeline delivery system. No on-farm construc-
tion was implemented. This was done in order to determine the
salinity effectiveness of making only lateral distribution improve-
ments. Water measurement at the headgate is accomplished by means
of a metering headgate. Water division is regulated internally
by means of two 8 inch x 3 feet (20.3 cm x 91 cm) Cutthroat flumes.
The 24 cm (10-inch) diameter plastic pipe was installed by various
irrigators on the lateral and Mesa County School District 51 (who
owns land under this lateral), and they all participated on a
cost sharing basis on the trapezoidal concrete ditch lining.
Lateral GV 95
Lateral GV 95 (Figure 39) was the largest lateral studied
under this project and also had the largest expenditures for im-
provements. It is basically a buried plastic pipeline and a con-
crete lined distribution system. There are considerable on-farm
improvements such as gated pipe, concrete lined head ditches,
field drainage and a side-roll sprinkler (Figure 40). There is
also a rather extensive tailwater collection and reuse system.
This has assisted in stabilizing lateral flows for better water
management and irrigation scheduling, as well as providing addi-
tion of water for the users. This lateral contains an additional
29 hectares (70 acres) which were consolidated from two other
laterals to minimize duplication of ditches and other structures.
All of the matching monies for construction of the mainline
distribution system were paid by the lateral users, and the work
was done by outside contractors. The matching money was collected
by the lateral users through charging each person $200 for the
first share of water and $40 for each additional share with left-
over funds going for future operation and maintenance (O&M) costs.
Most of the on-farm improvements were paid for in cash rather
than labor. As a consequence of this lack of direct involvement
in the construction, many of the lateral users did not have as
complete an understanding of the system operation as did water
users under other laterals who directly participated in the
101
-------
Grand ValleyCanal
100
Scale in meter*
0 200 400
Scale in feet
Legend
Drainage Ditch
Road
Canal
Buried Pipeline
Concrete Ditch
10"
CVJ
Figure 37. Map of lateral and on-farm improvements under GV 92
lateral system.
102
-------
*"'•''
IV^lEE
,
•2. - \ .»•••>* aw* r
Figure 38. Lateral GV 92 before and after installation of con-
crete ditch.
construction. Flow measurement is taken by five propeller meters
and 18 Cutthroat flumes, one Parshall flume and a 90 degree V-
notch weir which make a total of 25 measurement structures.
A total of 583 meters (1910 linear feet) of 15 cm (6-inch)
diameter gated pipe is in use on this lateral on 11.7 hectares
(28 acres), which required some educational and management in-
struction on its use and limitations. Six and one-half hectares
(16 acres) on the lateral received field drainage installation
(2,667 meters of 10 cm polyethylene drainage tile). Another
24.3 hectares (60 acres) received land shaping and leveling
treatments, which increased irrigation efficiencies on those
fields. However, some soil compaction problems were observed
during the first season.
On one 4.05 hectare (10-acre) field, a short (158.5 meter
or 520 foot) side-roll sprinkler was installed having an average
precipitation rate of 5.72 mm/hr (0.225 in/hr) and a UCL of 86.7
percent, UCC of 89.5 percent and a UGH of 88.8 percent. Water
is delivered to a sump via the concrete lined distribution system,
103
-------
;58cm.244m
E Road
Legend
— Open Droinoge Ditch
Rood
Field Boundory
Concrete Ditch
Gated Pipe
Sprinkler Irrigation
Field Drainage
Scu'r >n 'Ml
>OC 200 500
Nott 390m PipttMiic and
Toilwalfr Collection )
Not Sno.n
Di/o
1/2
SOcm.eim
(plutrjm
Pr«-pro|«cl
"••8lm flTxM
Figure 39.
Map of lateral and on-farm improvements under
GV 95 lateral system.
104
-------
a. Section of lateral at the
headgate before improve-
ments ;
b. Same section of lateral
after installation of a
buried pipeline;
c. Side-roll sprinkler in
operation;
View of side-roll sprin-
kler in alfalfa grass-
hay field.
Figure 40. Improvements on Lateral GV 95.
105
-------
A 10-hp single phase electric pump (6.94 1/s or 110 gpm) then
pressurizes the water to 4.4 x 1CP Newtons per square meter (65
psi) and transports it through a buried plastic pipeline to the
sprinkler. Irrigations are divided into thirteen 8- to 12-hour
sets. The cost per hectare was approximately $1,872 ($780/acre);
however, this system could easily be expanded to a 16- to 25-
hectare (40- to 60-acre) field at little additional cost, greatly
reducing the unit cost. An electric self-cleaning trash screen
(3.2 mm or 1/8 inch mesh), similar to the one shown earlier, was
installed at the entrance to the pump sump to minimize sprinkler
plugging. This system has worked quite well, and the very pleased
owners have stated that the increased yields due to the greater
irrigation uniformity have more than paid for the electricity
costs. Under the traditional "cut-and-dam" irrigation utilized
on this field, changing each set often took at least one hour.
Consequently, the sets were often left for 24 hours. Due to the
greatly reduced labor requirements (one-half hour maximum/set)
the sets are now 8 or 12 hours depending on water requirements
rather than labor requirements. This system was installed on
4.05 hectares (10 acres) of alfalfa and grass hay, which was
operated under a rigid irrigation scheduling program. There is
no field tailwater and deep percolation is very minimal. Seasonal
application efficiencies are on the order of 80 percent compared
to a historical average of around 40 percent.
Lateral GV 95 is a long (almost 3 kilometers in length) and
relatively narrow subsystem, and the speed of water deliveries
is, therefore, very important to a good water management program.
Prior to construction of the project, when the water was first
turned into the lateral in the spring, it often took as long as
two days for water to reach the end of the lateral. This slow
reaction time was very evident throughout the irrigation season,
and an irrigator had to cope with a continually varying flow as
the result of nonsteady upstream conditions and aquatic weed
growth.
The construction of concrete ditch linings and buried plas-
tic pipelines have had a tremendous influence on the speed of
water deliveries in this lateral. At this time, it takes only
one hour for the water to travel from the lateral headgate to the
end of the system. A fast reaction time is essential in order to
provide and to maintain uniform deliveries and to establish an
acceptable water rotation program. Project personnel assisted
lateral landowners in setting up an agreeable lateral water man-
agement program and rotation schedules. However, no one on this
lateral was personally willing to oversee the water management
program after completion of the project, and the operation has
reverted back to the "old" practices.
Reduced lateral seepage was quickly evidenced in several
cases on this lateral. These included a lack of water in base-
ments and the ability to cultivate lands immediately adjacent to
106
-------
the lateral which were no longer waterlogged during the entire
irrigation season. In addition, several large deeply eroded
channels were filled which resulted in more farmable land, safer
farming operations, and a much more aesthetically pleasing
landscape.
An operational problem encountered on this lateral was to
convince the lateral irrigators that the systems were not mainte-
nance free and that a regular program should be established. This
was well explained before construction; however, it seems that
some people still expected a "miracle" system that required little
labor, no maintenance, and was entirely self-regulating.
Lateral GV 160
This is the second largest lateral on which work was done,
and it has some of the most difficult salinity problems encounter-
ed in the Grand Valley (Figure 41). The land is very saline and
agricultural production is quite low. Treatment included the
installation of 2,573 meters (8,442 feet) of buried plastic pipe-
line, installed by persons on the lateral, and 1,898 meters
(96,229 feet) of lined concrete ditch. In addition, 11.5 hectares
(28.5 acres) received field drainage.
There are 27 measurement devices on this lateral to assist
in the distribution of water. There were no on-farm improvements
made other than the field drainage. The irrigators on the lateral
did all the pipeline installation and met matching requirements
on the concrete ditch linings. The landowner response was very
good. In fact, one landowner with no shares of water worked very
hard on the pipeline installation.
Maintenance requirements have been very low since the pipe-
line was installed for the main delivery system. Prior to the
project, the main system was very deeply eroded and choked with
weeds and cattails (Figure 42). As would be expected, late sum-
mer water delivery to the irrigated lands was less than one-half
the diversion at the headgate, and maintenance was frequent and
difficult.
Prior to construction of improvements under this project,
Lateral GV 160 and Lateral GV 161 paralleled each other from
their headgates for almost 1 kilometer without any water deliv-
eries, and yet the two laterals were not more than 3 meters apart.
As part of the project, these two laterals were consolidated into
one buried plastic pipeline. Since this portion of the line is
used only for delivery, and no water is diverted for irrigation
(although provisions were made at two locations to accept waste-
water into the system), it has a very low maintenance requirement
because of being self-flushing. Historically, this section was
a very high maintenance area with very high water losses. The
ditches were about 2 meters deep at places and overgrown with
107
-------
to Heodgate at Canal
I
Legend
— Drainage Ditch
— Road
Canal
Concrete Ditch
Buried Pipeline
Gated Pipe
Field Drainage
Laterals GVI60
and 6VI6I
Consolidated
25,30,a38cm
PVC Pipe 900 irf\
Toilwater
25cm,38m
Concrete
Pip«-x
E Road
Lateral GVI60 Separates—'
Concrete Lined (Pre-project)
38cm,61m Concrete Pipe-
Figure 41. Map of lateral and on-farm improvements under GV 160
lateral system.
108
-------
*
a. A farm delivery struc-
ture before improvements;
b. Farm delivery after con-
struction with flow
measurement structure;
c. Cooperators installing pipe-
line which consolidated two
laterals into one.
Figure 42. Improvements on Lateral GV 160.
109
-------
cattails and aquatic weeds. These laterals passed through a
subdivision, and the buried pipeline has minimized trash problems,
alleviated many health and safety hazards associated with children
playing in the area, and increased land values in the area because
of the more aesthetic appearance.
As part of the experimental design, it was decided that this
lateral would receive only a good delivery system comprised of
concrete ditch lining and buried plastic pipelines, some field
drainage works, and a network of flow measurement devices. There-
after, the water users would receive no instruction or irrigation
scheduling and/or suggested water management practices. However,
the resulting irrigations and practices were carefully monitored
by project personnel. As expected, the vastly improved delivery
system did cause a remarkable increase in irrigation activity on
this lateral and did result in better water management practices.
Much water was still wasted as the excesses were simply dumped
into drains. The headgate was not adjusted throughout the season.
Several acres of previously idle lands were replanted and irri-
gated, some for the first time in twenty years. The recovery of
water previously lost to seepage apparently made up the differ-
ence of water needed to irrigate these "new" lands as no conflicts
developed. Headgate diversions were actually slightly less than
historical.
Lateral MC3
This lateral is quite small (3.7 ha) but is one example of
the most saline land which,could be found in the Grand Valley.
In the early 1900's, this farm was a very productive pear orchard;
however, since the construction of the Government Highline Canal,
a high water table caused by over-irrigation on higher lands and
seepage from the Mesa County Ditch has completely put this land
out of production (Figure 43). The soil salinity is high and
contains large amounts of sodium salts or "black alkali" (sodium
adsorption ratio of the first foot of soil is in excess of 50).
This lateral was selected in order to demonstrate the possible
reclamation of highly saline agricultural lands.
Previously, the Mesa County Ditch, which runs across the
upper boundary of this farm, was lined with gunite as part of
the canal lining investigation. The first step towards reclama-
tion of .the lateral was to install field drainage to alleviate
the high water table and provide a mechanism to leach the salts
from the soil. The drains were constructed on a 12.2 meter (40-
foot) spacing on 2.5 hectares (6.3 acres) with 1,958 meters of
10 cm diameter tile (6,425 feet). The tile was installed by the
Grand Junction Drainage District.
The second step was to install a type of irrigation which
could apply light, frequent irrigation which would force the
salts to move down in the soil profile. One type of irrigation
110
-------
-
r
.
"* 3^-
a. Photograph of field in MC 3 showing the extreme salinity
problem; and
Figure 43.
b. Installation of cut-back
irrigation system with
measurement structure
for spillage and leakage.
Improvements on Lateral MC 3.
Ill
-------
which satisfies these criteria is automated cut-back furrow irri-
gation. This type of irrigation can apply light amounts of water
frequently and facilitate very high efficiencies. An automated
cut-back system was installed on this lateral (157 meters - 514
feet of concrete ditch).
Due to the extremely saline conditions, progress toward
reclamation has been slow and a return to full production is
expected to take several years. Water passing through the soil
profile and reaching the drainage pipe has shown that the system
is working as designed, and the land will eventually become prod-
uctive. A summary of improvements under this lateral is
illustrated in Figure 44.
Lateral MC 10
This lateral is the third largest, consisting of 54 hectares
(133.4 acres) and had a good water rotation program developed
prior to the project, because this lateral is one of the few in
the Valley which has always been somewhat "water short." This
same rotation is still in use, but has been greatly facilitated
by the constructed improvements.
The users on the lateral installed all the buried plastic
pipelines (1,054 meters or 3,040 feet) and have paid the matching
requirement for the lateral linings (2,723 meters or 8,935 feet).
Figures 45 and 46 depict the array of improvements incorporated
in this lateral improvement plan. In addition, 11.3 hectares
(28 acres) of productive land received land leveling treatment.
Several acres of previously idle land were put back into produc-
tion by the clearing of phreatophytic trees, shrubs, and land
leveling. The land leveling consolidated several smaller fields
into one, resulting in more efficient irrigations and more effi-
cient farming operations. The Grand Junction Drainage District
installed 4,958 meters of 10 cm diameter (16,265 feet of 4-inch
diameter) polyethylene plastic drainage tile for field drainage
on 6.1 hectares (15 acres) under this lateral.
Five hundred sixty-four meters (1,850 feet) of 15 cm and
20 cm (6-inch and 8-inch) gated pipe were installed on 6.7 hec-
tares (16 acres) under this lateral, and the use of such pipe
was well received by the irrigators. One farmer remarked that
he did not know how he irrigated before he got his pipe. A big
advantage of gated pipe is that it can be easily removed for
tillage, harvesting or other farming operations, and then quickly
replaced.
An automated cut-back irrigation system (Figure 47) was
installed on 4.05 hectares (10 acres) of barley, which was also
included as part of the field drainage construction on this
lateral. It should be mentioned that even though the cut-back
irrigation systems have been installed only on problem areas in
112
-------
Legend
— Drainage Ditch
—: Road
Canal
Field Boundary
Field Drainage
Concrete Ditch
100
Scale in meters
I 200 400
I |
Scale in feet
Figure 44. Map of lateral and on-farm improvements under MC 3 lateral system.
-------
Mesa County
Ditch
0 50 100
Scale in meters
6.1 hectares, 10cm Dia.
Plastic Tile on
12m Centers
>c
-------
a. Section of lateral prior b. Same section of lateral
lnin9- after construction of
linings (large trees were
removed).
Figure 46. Improvements before and after on a section of
Lateral MC 10.
this Project, it is also highly recommended for good, high ,
uction fields. This farm has experienced very remarkable im-
provement in crop yields in the past two years. The concept
cut-back irrigation with level bays was very novel to this far
and to others in the Valley, and he now supports this concept!
At thi time, there are 18 flow measurement devices on thi
lateral. These irrigators have been quite willing to use flow
measurement in their irrigation because they recognize its vain,
as a direct result of their previously developed mutual water
sharing program.
The seVl al acres of idle land which were leveled and/or
cleared of phreatophytes, planted, and irrigated increased the
demand for water. This resulted in changes in the fa
water rotation practices and required a larger degree of
115
-------
a. Close-up view of the automatic gate
developed as part of this project; and
. - • *r- p
b. The cut-back system in operation.
Figure 47. Improvements on Lateral MC 10.
116
-------
cooperation between irrigators. Project personnel worked closely
with the landowners to avoid any conflicts.
Water users served by this lateral were the most cooperative
group and were the most willing to change existing water manage-
ment practices. This was largely due to the existence of a pre-
project water rotation system which worked quite well.
These farmers installed the main delivery system (buried
plastic pipeline) and had a very good understanding of the system
operation and required maintenance. With little urging they
adopted a regular maintenance program and followed recommended
irrigation schedules. The concrete ditches and flow measurement
network was very beneficial in following recommended water man-
agement practices, and the easy-to-read flow measurement gauges
provided a large degree of confidence in the procedures.
Lateral MC 30
This one-landowner lateral was part of the earlier study on
field drainage and contains 3,353 meters (11,000 feet) of plastic
drainage tile on 2.4 hectares (10 acres). Further improvements
on this lateral included 1,040 meters (3,411 feet) of concrete
lining, 195 meters (640 feet) of 20 cm (8-inch) diameter buried
plastic piepline and 122 meters (400 feet) of 15 cm (6-inch)
diameter gated pipe. There are five flow measurement structures
on this lateral. This lateral and the improvements are presented
in Figure 48. Figure 49 illustrates before and after construc-
tion effects on this lateral.
The large alfalfa field on the west side of the lateral
previously had very long runs (almost 400 meters) and also had
a slight hill in the center of the field causing the irrigation
water to pond in the top half and rapidly run off on the bottom
half. To minimize this uniformity problem, the field was broken
into two runs using gated pipe. The gated pipe lies on top of
the aforementioned hill, and the 122 meter line is moved from
one side to the other side of the field during the irrigation
Use of gated pipe was called for in this case since a concrete
ditch would greatly interfere with the efficiency of harvestina
operations. The gated pipe could be quickly and easily moved
out of the way. Besides greatly increasing the irrigation
efficiency, the grower has noticed a marked increase in crop
production. ^
The eastern field of this lateral was the recipient of 3 353
meters of 10 cm plastic tile installed during the 1973 drainage
investigation. At that time, the sodic soils were very nonprod-
uctive and vegetation was sparse. At this tirr^ it- != 1 n°nprod-
that this field could be planted in WTsVa^alh valul crop"
such as barley with very good results. Many local growers have
117
-------
Legend
JV
I
Concrete Ditch
Buried Pipeline
Gated Pipe
Field Drainage
Open Drains
Roads
Canal
Rood
100
I
Scale in meters
0 200 400
1 | I
Scale in feet
4 hectare
10cm Plastic Tile
on 12m Centers
( Moved from East to
West Side of Field )
Figure 48.
Map of lateral and on-farm improvements under MC 30
lateral system.
118
-------
a. Section of lateral prior
to construction of im-
provements.
b. Same section of lateral
after construction.
Figure 49. Improvements on Lateral MC 30.
commented on the very noticeable change in crop quality as
evidence of the successful reclamation due to the field drainage.
The installation of the concrete lining greatly reduced the
maintenance requirements for the main delivery system which his-
torically was very demanding. Prior to the project, late season
flows at the field were often about one-half of the initial
season deliveries due to a large population of willows and other
phreatophytic growth. The concrete linings and gated pipe irri-
gation system greatly reduced the labor for changing individual
irrigation sets.
Drainage
Field drainage for relief of localized waterlogging problems
was analyzed on the basis of past drainage studies in the Grand
Valley and was diagnosed by the installation of observation wells
in several areas. A total of 36.8 hectares received drainage
119
-------
either by interceptor drainage (10.2 hectares) or by field drain-
age (26.6 hectares). The locations of drainage installations
are shown in Figure 50. Four hundred forty-two meters of 20 cm
(8-inch) diameter concrete tile were installed for use in the
interceptor drains. A total of 13,079 meters of 10 cm (4-inch)
diameter corrugated polyethylene plastic drainage tile was in-
stalled for the field drainage. This does not include 3,353
meters of 10 cm (4-inch) diameter of similar plastic tile in-
stalled on 4 hectares in the earlier drainage investigation in
the demonstration area. All the fields which received drainage
improvements were topographically mapped and had a series of
observation wells installed to monitor the effectiveness. Efflu-
ent outflows and the wells were monitored for chemical quality
and quantity as well as groundwater elevations.
All drainage works were installed by the Grand Junction
Drainage District. The project furnished all materials for con-
struction, and they provided all the equipment and labor neces-
sary for the installation, consistent with their standing policy
arrangement for this type of work. The work performed by the
Grand Junction Drainage District more than satisfied the 30 per-
cent matching requirements. The interceptor drains were concrete
tile because they were installed in areas where plant roots would
present problems, and the maintenance machinery used to correct
this problem by the Grand Junction Drainage District would not
work in a plastic tile. The typical installation of field drain-
age is illustrated in Figure 51. The actual installation is
depicted in Figure 52.
Additionol Fill
to Allow for
Settlement
Partially Compacted
Backfill
E xcovoted
Trench
Protective
Plastic
Strip
Sand and Gravel
Filter
•Drainage Pipe
10cm-
Figure 51. Typical installation of field drainage in the
demonstration area.
120
-------
Stub Ditch
Government
Highline
Canal
Scale I Kilometer
Scale I Mile
Grand Valley Canal
Mesa County
Ditch
LEGEND
3 Previous Drainage Work (1973)
Field Drainage
Interceptor Drains
Figure 50. Location of drainage installations in the Grand Valley Salinity Control
Demonstration Area.
-------
a. Installation of field
drainage on Lateral
GV 95;
I
f
r
b.
Ife
Tile placement in trench
before final envelope;
c.
,
Tile placement on Lateral
MC 10;
d. Installation of drainage
on Lateral MC 3.
Figure 52. Relief drainage installation in the Grand Valley.
122
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SUMMARY OF IMPROVEMENTS AND COSTS
The total value of the lateral improvements for the project
is $378,324.51, installed on 330.7 hectares for an average cost
of $1,144.01 per hectare. The amount spent in project funds was
$241,984.00 and the value of the participant matching was
$136,340.51. A summary of the lateral improvements is presented
in Table 15. The costs of the individual improvements are
presented by lateral and are summarized in Table 16.
Under the terms of the project grant, as discussed in
Section 6, the construction was to be cost shared on a 70 percent
(project) - 30 percent (local participant) arrangement. The
required matching on $241,984.00 was $103,626.17. All the
project funds available for construction were stretched to the
limit in order to maximize the number of improvements.
An illustrative summary of all the applied research on
salinity control of irrigation return flows in the Grand Valley
of Colorado is presented in Figure 53. The total improvements
completed in the project area since 1969 as part of the demon-
stration of salinity control include: 12.2 km (7.6 miles) of
large canal linings, 16,432 meters (53,913 feet) of perforated
field drainage tile, construction of a wide variety of on-farm
improvements, and an irrigation scheduling program. The costs
of the various improvements, which totaled almost $750,000, are
listed in Table 17. The total combined improvements removed
almost 12,300 metric tons of salt per year. The resulting
"average" cost-effectiveness is $60.48 per metric tons of salt
removed. The resulting benefit-cost ratio based on downstream
damages of $150 per metric ton is 2.50.
123
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TABLE 15. SUMMARY OF PROJECT IMPROVEMENTS ON THE LATERAL SUBSYSTEMS
to
Types of Improvements °
Concrete Ditches (m)
Buried Plastic Pipelines
Gravity systems (m)
Pressurized systems (m)
Gated Pipe (m)
Drip Irrigation (h)
Overhead Sprinklers (h)
Sideroll Sprinklers (h)
Drainage Works (h)
Plastic Drainage Tile (m)
Concrete Drainage Tile (m)
Flow Measurement (No.)
Cutthroat Flunes (No.)
90' V-Notch Heirs (Mo.)
Par shall Flumes 3 (No. )
12* Propeller Meters (No.)
10" Propeller Meters (No.)
8* Propeller Meters (No.)
Other Meters (No.)
Metering Headgates (No.)
Debris Removal Equipment (No.)
Land Shaping, etc. (h)
Irrigated Hectares (Possible)
Total Value ($)
value/Hectare ($)
Value/Irrigated Hectare (S)
HL C HL E
(13.1 h) (35.9 h)
1
786
3,274
5.2
2.2* 8.0 *
244 198
(3) (4)
2
1
2
1
1
1
11.5 34.2
$ 4,857.92 $30,758.33
S 370.83 856.78
$422.43 899.37
PD 177
(27.8 hj
230 1
2,051
207
2.2
(14)
3
1
3
1
1
3
2
1
*
21.3
$43,973.43
1,581.78
1,937.16
GV 92
(24.3 h)
189
817
(3)
2
1
10.4
$13,600.56
557.69
666.69
GV 95
(79.1 h)
2,789
2,312
378
583
4.0
6.5
2,667
(25)
18
1
1
1
2
1
1
1
24.3
69.8
$104,788.80
1,324.76
1,501.27
GV 160
(78.7 h)
1,189
2,5735
11.5
3,496
(27)
26
1
51.4
$84,675.90
1,075.93
1,582.73
MC 3
(3.7 h)
157
2.5
1,958
(3)
2
1
3.0
$18,440.73
4,983.98
6.146.91
MC 10
(54.0 h)
2,723 L
1,054
564
6.1
4,958
(18)
14
2
1
1
11.3
44.2
$68.543.81
3,269.33
1350.76
MC 30
(14.1 h)
1,040
195
122
2
(5)
3
2
13.8
$8,685.03
615.96
629.35
TOTAL
(330.7 h)
9,026
9.788
3,652
1,476
2.2
5.2
4.0
36.8
13,079
442
(102 TOTAL)7
70
3
1O
3
4
6
4
2
3
35.6
259.6
$378,324.51
$ 1. 144.01
$1. 457.34
These laterals were part of the earlier canal and lateral lining study and contain approximately an additional 139O meters of concrete ditches and
390 meters of concrete pipe not included above.
This lateral was part of a previous drainage study and contains an additional 3353 meters of plastic drainage tile on 4 hectares not included above.
These flumes were removed at the end of the project since they measured field runoff.
Interceptor drains, concrete tile. HL C tiled a large open drain, HL E is a new drain.
Includes 99 meters of 25 and 38 cm diameter concrete pipe.
• = meters, h * hectares. No. = number.
This total flow measurement count does not include the flow measurement structures used in monitoring the hydrology for the whole demonstration area.
-------
COST SUMMARY OF PROJECT IMPROVEMENTS ON THE LATERAL SUBSYSTEMS
I-1
IS)
Ul
Improvements
(Materials + Installation) HL C
Concrete Ditches
Misc. Concrete Ditch Structure S 113.60
Buried Plastic Pipelines
Gated Pipe and Accessories
Drip Irrigation *
Overhead Sprinklers '
Sideroll Sprinklers
Plastic Drainage Tile
Concrete Drainage Tile 2,290.41
Pre-cast Cutthroat Flumes
V-notch weirs 117.31
12" propeller meter
10" propeller meter
8" propeller meters
Other meters
Meterinq headgates
Debris Removal Equipment
Misc. (Cut -back gates)
TOTAL PROJECT COSTS S 2,521.32
MATCHING - NON-MONETARY 3 2,336.60
TOTAL VALUE S 4,857.92
HL E
S 40.00
2,358.05
15,905.87
217.00
96.56
362.21
475.64
399.35
S19.854.68
10,903.65
$30,758.33
PD 177
$ 1,281.0O
335.00
16,010.21
1,408.36
8,513.47
144.84
193.88
436.46
396.41
1,142.63
1,442.55
409.00
$31,713.81
12,259.62
$43,973.43
GV 92 GV 95
$ 2,755.00 $15.785.00
279.50 2,329.24
66.34 23,066.14
4,300.95
5,597.02
15,262.02
96.56 869.04
186.00
436.46
792.82
362.21
267.02
346.18
385.00
$ 3,543.58 $69,638.92
10,056.98 35,149.88
SI 3,600. 56 $104,788.80
GV 16O
$10,892.00
4,215.00
17,125.30
19,798.40
1,255.28
396.41
$53,682.39
30,993.51
$84,675.90
MC 3
$ 2,153.50
327.50
8,747.66
96.56
314.85
598.86
$12,238.93
6,201.80
$18,440.73
MC 10
$15,844.78
4,001.87
9,281.40
4,432.51
17,757.00
675.92
436.46
362.21
787.86
$53,580.01
14,963.80
$68,543.81
Total
MC 30 Costs
$5,628.15 $54,339.43
840.00 12,481.71
740.00 68, 6-1 7. 44
875.24 11,017.06
8,513.47
15,905.87
5,597.02
61,782.08
2,290.41
144.84 3,379.60
497.19
1,309.38
1,585.64
2,229.26
2,185.21
661 . 03
1,386.72
$ 8,228.23 $255,001.87
456.80 123,332.64
$ 8,685.03 $378,324.51
1 Project costs include monetary matching received from participants
2 Costs include pressurized pipeline costs
3 Includes land shaping, pipeline installation, drainage installation, equipment rentals, etc., any costs incurred by the participants and/or any
hectares, one 0.7 hectares (for a tot.l of 2.2 hectares) - second to be expanded by participant to cover
3.0 more hectares - making a total 5.2 hectares under drip.
5 Does not include costs of installation which were included in concrete ditch costs ($20.00 each).
-------
Legend
Woter Supply
iGrond Valley Canal
ro
(Tt
V/////////flA Land Under Study Lateral
t:::::::::'x':::':':':-| Previous Drainage Study
Irrigation Scheduling Project
Hydrologic Boundary
Canal or Ditch (No Improvements)
Drain or Wash
Trapezoidal Concrete
Slip-form Lining
Gunite Lining
Gunite,Downhill
Bank Only QV 16
Stub Ditch
overnment
Highline
Canal
/ Price Ditch
Scale I Kilometer
Figure 53.
Total project improvements in the Grand Valley Salinity Control
Demonstration Area, 1969-1976.
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to
TABLE 17. SUMMARY OF CONSTRUCTION OF IMPROVEMENTS BY THE GRAND VALLEY SALINITY
CONTROL DEMONSTRATION PROJECT
Map Company Name
Designation Canal Name
Area I (Demonstration Area)
A
B
C
D
E
Area II
F
Area III
Grand Valley Irrigation Co.
Mesa County Canal
Palisades Irrigation Dist.
Price Ditch
Grand Valley Haters Users
Assn. Gov't Highline Canal
Mesa County Irrigation Co.
Stub Ditch
Grand Junction Drainage Co.
Open Drains
Closed Drains
Laterals
Grand valley Irrigation Co.
Grand Valley Canal
G Redlands Hater and Power
SUBTOTAL
Drainage Costs
SUBTOTAL
Lateral Improvements
TOTAL VALUE of direct benefits to the
Miscellaneous Total
Type of Length Perimeter Area Unit Cost Casts v Cost
Improvement (mi.) (tan) (ft.) (m) {y<&) tm*> ($/yd2) <$/n2) ($)
Gunite Lining 2.2 3.5 14 4.3 17,500 14,632 3.25 3.89 2,100.00
Slip Form Lining 1.9 3.1 15 4.6 16.720 13.980 3.25 3.89 2.90O.OO
Gunite Lining 1.0 1.6 IS2 4.6 8,800 7,358 3.50 4.19 5,800.00
Slip Porm Lining 2.5 4.O 10 3.1 14,700 12,290 3.25 3.89 3,500.00
Slip Pont Lining
Tile
Slip Porm Lining 4.83 7.77
Gunite Lining 0.15 0.24 IS2 4.6 1,320 1,104 3.50 4.19 4,000.00
Slip Pom Lining 0.5 0.8 12 3.7 3,500 2.926 3.25 3.89 1,600.00
(ft) (m) (in.) (cm) (ac) (ha) (S/ac) (S/ha)
11.000 3,353 43 10. 23 10 4.1 1,694.00 4,185.82 O.OO
Grand Valley
($)
58.975-00
56,240.00
36.600.00
51.275.00
4, OOO.OO
16.000.00
110,815.00
8,620.00
11,475.00
354,000.00
16,940.00
$370,940.00
378,330.00
$749,27.0.00
Costs of pre—construction and post-construction ponding tests above amounts in CSV contract, plus costs of installing headgates, etc.
2 Downhill bank lining, only.
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SECTION 8
PARTICIPATION AND RESPONSE BY IRRIGATORS
AND LOCAL ORGANIZATIONS
LOCAL PARTICIPATION
The evaluation of a lateral in a subsystem context allows
improvement of water management practices throughout the individ-
ual farms by providing more control of the quantity of flow and
the time of water delivery. Efforts to maximize water management
efficiency within a lateral subsystem requires substantially more
interaction (unless the irrigation system is highly automated)
among the irrigators themselves; thus, an important aspect of
this project is the evaluation of these interactions. Also, the
willingness and extent of involvement by local organizations
would be very critical to the successful implementation of a
valley-wide salinity control program.
Irrigator Response Prior to Construction
The project was initiated by a newspaper article inviting
interested parties to an explanatory open house. More farmers
responded to the open-house than could be included in the study.
A strong emphasis was made at the open house discussions that
the primary interest in undertaking this research and demonstra-
tion project was to reduce the salt load in the Colorado River;
however, a significant by-product of this emphasis would be
increased agricultural productivity under the lateral subsystems
improved by this effort. Meetings were later held in the homes
of the interested irrigators under the several lateral subsystems
where specific details for cost-sharing and anticipated types of
irrigation system improvements were discussed, including the time
schedule for preconstruction field investigations, construction,
and postconstruction operations.
The irrigators were generally willing to cooperate with the
project, although most merely wanted to rehabilitate the existing
laterals. Project personnel continuously received requests to
study other laterals and to provide financial and technical
assistance.
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Participation by Local Organizations
There has been a large amount of participation by local
organizations, which contributed substantially to the project's
success. The largest degree of participation was by the Grand
Junction Drainage District, closely followed by the Mesa County
Road Department and the local irrigation companies.
The Grand Junction Drainage District, through their standard
drainage tiling agreement (the Drainage District will install the
drainage works if all materials are supplied by the owner or
other parties), installed more than 13,000 meters of drainage
tile for this project. Their participation and cooperation is
greatly appreciated.
The Mesa County Road Department installed and replaced nu-
merous road crossings and culverts and provided some backfill for
deeply eroded areas near county roads.
The Grand Valley Irrigation Company and the Grand Valley
Water Users Association provided much assistance on modifying
lateral operational procedures and by replacing worn out head-
gates. They also agreed to let project personnel completely man-
age the headgates on the selected laterals, which was a very
important component of the project's operation.
Meetings were held with the Grand Valley Rural Electric
Association, Mesa County Tax Assessor, Mountain Bell Telephone
Company, local natural gas companies, bank officials, attorneys,
and water and sewer district officials in order to obtain neces-
sary information, cooperation, and any other assistance on con-
struction easements, utility locations and relocations, possible
legal problems, and various financial aspects of the project.
Almost 610 meters (2,000 linear feet) of 30 cm (12-inch)
diameter plastic irrigation pipeline was installed, free of
charge, by a local construction company. They installed the
pipe because Lateral GV 160 crossed about 122 meters (400 feet)
of land belonging to the company. In order to make the area
more usable for their construction related activities, the con-
tractor offered to install the pipe at no charge. The project
supplied all the materials.
In general, the support given by local businesses and organ-
izations has been overwhelming and undoubtedly a very large
reason for the attainment of the project's objectives. The
Grand Junction Daily Sentinel, a local daily newspaper, was of
great assistance in promoting project goals and reporting on
project activities and developments.
129
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Irrigator Participation During Construction
The scope of this study involved the selection of laterals
in the demonstration area in which the irrigators served by the
laterals would participate on a matching basis (70 percent proj-
ect funds - 30 percent irrigator funds) in the construction phase
of the study. In general, the irrigators on the larger laterals
found it difficult deciding how each should contribute to the
matching requirement. On the smaller laterals, the decisions
were usually much simpler because there were fewer persons in-
volved. These decisions were complicated by the fact that the
30 percent matching requirement could be partially or totally
paid in labor, equipment rental, or other types of compensation
(voluntary assistance by the Drainage District, etc.).
On the GV 95 Lateral, the 15 participants opted to pay their
matching in cash for the main conveyance-distribution improvements.
Their decision for the collection of the money involved the pay-
ment of $200 by each person on the ditch for the first share of
irrigation water and a much smaller amount for each additional
share. Interestingly, the individual who proposed this method
of collection was a water user having only a single share, who
felt that each water user gained significant benefits from the
improvements that could not be equitably measured by shares alone.
Any money left after completion of the project was committed for
future maintenance of the lateral works.
Laterals PD 177, GV 160, MC 10, and GV 92, on the other hand,
opted to do much of the work on the installation of the mainline
distribution systems themselves. However, this was only appli-
cable on buried plastic pipelines where the people could handle
the installation. In almost every case, the value of the labor
and equipment used in installing the pipeline averaged almost
exactly 30 percent of the cost of the pipe, flow meters, and
appurtenant structures. On these laterals, the irrigators still
had to monetarily match on any contracted concrete-lined ditches.
On Lateral MC 30, the one farmer using this lateral had
decided on a combination of concrete-lined ditch, buried pipe-
line, and gated pipe. He installed the pipeline and paid match-
ing money for the concrete ditches and the gated pipe.
On Lateral HL C, the improvements consisted only of laying
tile in a large open drain which bisected a field and the instal-
lation of flow measurement structures. The Grand Junction Drain-
age District does this type of work as a matter of policy, and
their work on this lateral more than met the matching requirement.
Lateral HL E is almost all apple, pear, and peach orchards.
The work undertaken on this lateral involved the installation of
an overhead sprinkler system on 5.2 hectares of pears, and the
installation of a buried plastic pipeline. The two owners
130
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(brother and sister) opted to have a contractor do all the in-
stallation and paid their matching requirement in cash. The
overhead sprinkler system is attracting quite a lot of valley-
wide attention due to the fact that it can be used for frost
control and for cooling, as well as irrigation. It is the first
such installation in the Grand Valley. The interceptor drain
and 25 cm diameter tailwater pipeline were installed by the Grand
Junction Drainage District which more than met the lateral match-
ing requirements for this improvement.
As mentioned previously, several of the lateral groups
elected to do much of the construction work themselves and were
thus very involved in the day-to-day operations. On other
laterals, where the construction was done by outside contractors,
some of the irrigators were out every day asking questions and
making suggestions on construction procedures and how to improve
performance of the system. The willingness of the irrigators to
become involved in the construction is desirable because they
develop a much better understanding of the system design, oper-
ation, and maintenance. However, on one lateral (GV 95) the fact
that the irrigators opted to pay for the construction contributed
to many problems encountered later in the project. Due to the
lack of daily involvement, many of these irrigators did not com-
pletely understand the system and its operation. Ultimately,
this caused some personal conflicts which should not have occur-
red. However, with considerable time and effort, these conflicts
have been resolved.
The construction work was very personally gratifying in many
ways, and community effort was often required to complete the
work. Many times people went out of their way to help and assist
others on the laterals. For example, on the Price Ditch 177
Lateral subsystem, several people from the subdivision at the
tail end of the lateral assisted in the laying of the pipeline
for agricultural users. In fact, some of them even took vacation
time from their jobs to work on the project. Two of the people
donated their own equipment for construction of the project.
In another case, on the Grand Valley Canal 160 Lateral sub-
system, people without water rights in the lateral assisted their
neighbors in the pipeline construction. Also, this same lateral,
a 20 cm (8-inch) plastic pipeline, replaced more than 400 meters
(1/4 mile) of unlined ditches to one farm. The pipeline was
completely installed by the neighbors (some of them are not even
served by this lateral) of the family because the head of the
household had just suffered a heart attack.
On the Mesa County 10 Lateral subsystem, people donated
their own equipment for the construction of the pipeline system
and received no reimbursement from their neighbors. One elderly
gentleman with just a few acres had his sons come and do his
share of the work on the pipe installation. In fact, this was
131
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very common on many of the laterals where community effort was
required to complete the work. And generally, if a person could
not come and work, he would hire someone to take his place.
Irrigator Response After Construction
The mutual cooperation between irrigators on the project has
improved quite noticeably since construction began, particularly
where the participants did much of the installation themselves.
The new systems have reduced some antagonism which had been due
to real or imagined inequalities in the requirements for ditch
maintenance or inequitable allocation of water. For instance,
under the new systems the maintenance requirements are generally
much less because of concrete lined laterals or the use of pipe-
lines. Also, ineffective and old division structures were re-
placed with new structures containing flow measuring devices,
removing many areas of previous contention because of the more
equitable distribution of the irrigation water supplies. However,
on Lateral PD 177, there is still one irrigator who refuses to
work with the other irrigators primarily due to a lack of under-
standing of the system operation.
As noted earlier, some of the laterals had previously devel-
oped water rotation agreements. The construction of these new
systems greatly facilitated the ease and speed of water deliveries
and contributed to the development of a new awareness of water
rights through water measurement, all of which has promoted
mutual cooperation. Consequently, rotation programs have become
more widely accepted as a beneficial practice.
The actual construction process helped many irrigators to
become much more aware of water delivery problems. They now have
more consideration for their neighbors. There is more communi-
cation between irrigators to determine the times and amount of
deliveries because of the increased emphasis upon improved water
management practices.
With very few exceptions, the local participants were fully
cooperative with the project and were very patient with construc-
tion delays and small problems which developed. Any complaints
or suggestions were expeditiously evaluated and answered. In
almost every case, complaints were a result of persons misunder-
standing the operation of the new systems, which had been pre-
viously explained, but were often radically different from their
old methods. When the new methods and procedures were explained
and demonstrated, most all persons were satisfied with the results,
CHANGES IN IRRIGATION PRACTICES
An important part of the initial lateral selection procedure
was to assess the willingness of individual irrigators to change
132
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existing irrigation methods and practices. This was critical
since the proposed systems would often be designed in such a way
that a return to old methods would be practically impossible, and
the new proposed management methods might be mandatory for con-
tinued operation of the system. The results and implications
were fully explained to all the participants before any final
decisions were mutually agreed upon.
In the demonstration area, and the Grand Valley in general,
irrigators are very reluctant to change past practices and
methods. Water costs in the area range from about $9.90/ha-m
to about $43.80/ha-m ($1.22/AF to $5.40/AP) for the season, so
with the abundant low-cost water there is little economic incen-
tive to improve efficiencies. Rehabilitation and improvement of
the conveyance systems were of much more concern than on-farm
changes, and, as a result, there were numerous problems in
getting individual irrigators interested in improving their own
farm irrigation systems and practices. Even where it had been
demonstrated that improvements led to increased yields, higher
irrigation efficiencies, and reduced fertilizer costs, the
general attitudes were negative. Only the more progressive and
innovative farmers were willing to try new methods.
The attitudes concerning field drainage were also negative
for the most part. Many irrigators believed that this type of
drainage was not really required since the large, widely spaced
open drains in the area were functioning adequately in their
opinion (in reality, these drains intercept only 27 percent of
the total groundwater flows, and of the total flow carried in
the drains, only 22 percent is groundwater, the remainder is
surface flow which is mostly tailwater runoff). Research
results to date have shown that these open drains are largely
ineffective in draining nearby croplands.
Although most farmers can associate overirrigation with
drainage problems, little concern is evidenced because the
drainage problems generally occur in the lower parts of the
Valley and, therefore, do not usually directly affect the
inefficient and ineffective irrigator. The fact that the Grand
Valley is the largest contributor of salinity per acre in the
Upper Colorado River has no impact upon the average farmer in
the area, who has no sympathy for the salinity damages being
received in the Lower Colorado River Basin and the Republic of
Mexico. There is some justification for their attitudes since
they have been irrigating their lands for decades, and they have
not contributed to the recent increases in salinity concentrations
in the lower reaches of the Colorado River.
There is a large local resistance to irrigation scheduling
in the Grand Valley, again probably due to the abundant, low-
cost water supply. Past and on-going irrigation scheduling pro-
grams in the Valley have a history of poor communication between
133
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the farmers and the schedulers. In addition, there were definite
weaknesses in the irrigation prediction methodology which became
evident to the farmers very rapidly. These unfortunate results
during the initial irrigation scheduling efforts are responsible
for a large portion of the local resistance. To overcome these
initial setbacks and regain farmer acceptance and credibility
requires an even more significant demonstration of the benefits
that can result from just irrigation scheduling.
Surprisingly, there was also some resistance to changing
from open ditches to buried pipelines. One startling reason was
that the people did not feel comfortable with the pipelines since
they could not see their water. Another reason was that they did
not believe that a pipe could carry as much water as their old
weed-choked, large open ditch. Their primary preference was for
concrete-lined ditches. However, there is a rapidly growing
acceptance of pipelines as irrigators realize the rapid response
of such water delivery systems, as well as the additional water
control benefits and flexibility which result from pipelines.
IRRIGATOR ASSESSMENT OF IMPROVEMENTS
Almost all irrigators have been quite satisfied with the
improvements and system performance. For example, the pear crop
under the overhead sprinklers was saved in the spring of 1976
with the frost protection aspect of the system. In the owner's
words "the system has already paid for itself" ($3,336/ha). in
another case, using a side-roll sprinkler system, the owner has
stated that the increased hay production due to the greater uni-
formity more than offset the costs of pumping (10 hp pump).
The most commonly heard assessment was that "It sure beats
what we had." Irrigators have been quite favorably impressed
with the small amount of maintenance required and the speed with
which the system responds. On GV 95, for example, previously
when water was first turned on in the spring, it often took 12
to 20 hours to travel one kilometer, and they now have to hurry
to their fields in order to arrive at the same time as the water.
Several farmers have commented that they have already noticed big
improvements with some previously waterlogged soils, and a lack
of water in their basements due to just lateral seepage reductions
(although deep percolation losses are also a significant contrib-
utor to basement water problems).
The project has been for the most part beneficial to the
irrigators, as well as very educational to the writers. The fact
that the irrigators had to cooperate with each other in order to
initially participate in the project, plus the esprit de aorpa
developed during the construction_process, are largely respon-
sible for the success of this project.
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IRRIGATION FIELD DAYS
On August 6 and 7, 1976, an Irrigation Field Days was held
in Grand Junction that included an irrigation equipment show,
tours of the demonstration project area, and tours of the EPA
funded research project, "Irrigation Practices, Return Flow
Salinity, and Crop Yields."
A "Field Days" to be held towards the end of the last year
of the project was a part of the initial research proposal. This
event was to be directed primarily toward growers in the Grand
Valley and secondly to irrigation leaders (mostly growers)
throughout the Upper Colorado River Basin. The primary purpose
was to acquaint these target people with what had been done in
the past three years, to present preliminary conclusions, and to
present ideas on the direction of future salinity control programs.
Preparation
The original Field Days concept was broadened to include an
irrigation equipment show in addition to special educational pro-
grams and field tours, and evolved into the "Irrigation Field
Days." Hopefully, the equipment show would provide an additional
incentive to attract farmers to the Irrigation Field Days and
would also help fulfill a needed educational function in the
Grand Valley. The scope of the presentations on the research
was also broadened to include all the EPA funded research conduct-
ed by the Agricultural and Chemical Engineering Department of
Colorado State University in the Grand Valley since 1969.
Due to the expansion of the program, the Irrigation Field
Days was cosponsored by the Colorado State University Cooperative
Extension Service. The show and tour headquarters was the Two-
Rivers Plaza, a Grand Junction municipal center constructed in
1975, which contains 1,670 square meters (18,000 square feet)
of exhibit space plus several meeting rooms.
Fifteen thousand brochures and seven hundred posters (Figure
54) were printed for circulation throughout the Grand Valley and
the Upper Colorado River Basin. Project personnel traveled ex-
tensively throughout the basin to distribute literature and con-
tact prominent irrigation leaders, agriculture oriented busines-
ses, extension personnel, and local news media concerning the
Irrigation Field Days. In Western Colorado, the names of farmers
and landowners were obtained from local ASCS mailing lists and
about 5,000 brochures were mailed directly to as much of the
agricultural community as possible. In the other Upper Basin
states, brochures were mailed to local Extension Service Agents
for distribution through their mailing lists. Also, 200 of the
posters (which were placed in public places and store windows
throughout the Upper Basin) had small pockets attached for
135
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IRRIGATION
FIELD DAYS
August 6-7, 1976
Two Rivers Plaza
Grand Junction
Colorado
Of particular interest to
farmers in the Upper
Colorado River Basin
Figure 54
Advertising brochure and poster design for Irri-
gation Field Days.
136
-------
brochures in order to distribute the information to persons who
were not on the other mailing lists.
An extensive mass media advertising campaign was also
undertaken in the Upper Basin States. A 5-minute interview tape
was sent to Grand Junction TV and radio stations, and 30-second
public service announcements (PSA's) were sent to radio stations
throughout the Upper Colorado River Basin. The Cooperative
Extension Service advertised on their weekly information radio
shows and released several flyers to agents for general infor-
mation and distribution. In addition, a local Grand Junction
radio station (KEXO) ran a 15-minute live interview. Advertise-
ments, or 30-second "spots" were purchased from the following
media: Colorado Raneher and Farmer (a monthly statewide periodical
(33 000 circulation) ; Montrose Daily Press of Montrose, Colorado;
Sun-Advocate of Price, Utah; The Daily Sentinel of Grand Junction,
Colorado; KREX radio of Grand Junction. Also, the Irrigation
Journal, a monthly nationwide publication, mentioned the
Irrigation Field Days in their "Dates of Interest" and "Irri-
gation News" columns. The Grand Junction office of the USDA,
Soil Conservation Service prints a quarterly newsletter which
goes to 1,300 persons in the Grand Junction area; and they also
included an article on the Irrigation Field Days which was
mailed about one week prior to the event.
The Grand Junction Daily Sentinel ran several articles
preceding the Irrigation Field Days and provided very good
coverage during the show. Several other publications, including
the Colorado Ranoher and Farmer, ran followup stories concerning
the Irrigation Field Days.
The Equipment Show
A card file of potential exhibitors was developed from
magazine ads, equipment files, and personal contacts. Initial
invitations to exhibit were sent in March-May to over 200 irri-
aation equipment manufacturers and suppliers and other agri-
cultural service businesses. The response was very gratifying
and, ultimately, the equipment show consisted of a total of 46
exhibits, of which 41 were commercial and 3 were state and
federal governmental agencies (Colorado Water Conservation
Board USDI-Bureau of Reclamation, and USDA-Soil Conservation
Service), and one exhibit booth was for the project. The state
and federal agencies requested booths in order to present their
plans for future action programs on salinity control activities
in the Grand Valley.
The Project Program
The portion of Irrigation Field Days associated with the
project involved a one-day program repeated on both days. Original
plans called for four tours to run each day, and each tour was
137
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to be three hours in length. Two-46 passenger buses were rented
for this purpose. Project participants were available to talk
to persons on the tours and also at the project's exhibit booth.
There was no cost to the farmers for either the equipment show
or the tours. During the day, a 16 mm 25-minute general interest
irrigation movie entitled "The Magic of Water" (Alberta Agricul-
ture) and a 20-minute 35 mm narrated slide show entitled "The
Grand Valley: An Environmental Challenge" were also shown period-
ically in the meeting rooms adjoining the exhibition area. The
Grand Valley slide show was prepared in 1974 to explain in non-
technical terms the results and thrust of CSU salinity research
since 1968 to the local Grand Valley residents.
On the evening of August 6, a special educational program
was planned from 7 to 9 p.m. with talks on topics of special
interest to local farmers and landowners. These included pre-
sentations on irrigation scheduling, frost protection by sprin-
kling for orchards, and drip irrigation. Figure" 55 illustrates
the many activities of the Irrigation Field Days.
In addition, 1,000 copies of a 55 page nontechnical soft-
bound report was prepared for distribution at the Irrigation
Field Days. The report discussed past research activities and
explained the basic reason for the salinity problem in the Grand
Valley. The two concurrent research projects, their primary
emphasis and preliminary conclusions were presented. Numerous
photographs and maps were used to illustrate the text. Figure
56 shows the cover of the Irrigation Field Days report.
Response
Five hundred and sixty-one (561) persons registered, 380 of
which were on Friday. However, many people avoided registering
even though there was no registration fee, and also some persons
registered for a group. The receptionists, who handled the regis-
tration and attempted to keep an accurate counting of those who
did not want to register, estimated that at least 800 persons
actually visited the show. Seventy-two percent (72 percent) of
the registrants listed a home address outside of Grand Junction,
and 18 percent were from outside of Colorado. Thirty-seven per-
cent of the registrants were farmers/ranchers, 19 percent were
with businesses, 16 percent were with various local, state, and
federal government agencies, 9 percent listed other occupations,
and 18 percent listed no occupation. Table 18 presents a detail-
ed breakdown of the registrants' homes and occupations.
The Friday night (August 6) presentations had 110 persons
in attendance. Farmers seemed to respond quite favorably to
these talks and asked a large number of preceptive questions.
All of Friday's scheduled bus tours were full to capacity
and an additional bus was rented to accommodate an extra tour.
138
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IRRIGATION
il HtLD DAYS
a. Front of Two River Plaza,
site of the Irrigation
Field Days;
^^r^m
L f'-jUm
b. A cooperator discussing
improvements on his farm
during a tour; and
c. Special educational program offered on the
evening of August 6, 1976.
Figure 55. Irrigation Field Days.
139
-------
IRRIGATION
FIELD DAYS
REPORT
1976
A Report
of CSU's
Salinity Research
in Grand Valley
Sponsored by
the EPA.
\
Figure 56.
Cover of Irrigation Field Days report which was
printed in blues, greens, and white.
140
-------
TABLE 18. IRRIGATION FIELD DAYS REGISTRATION BREAKDOWN
Home Address;
In-State
Grand Valley
Outside Grand Valley
TOTAL
159
300
459
Occupation;
Out-of-State
Utah
California
New Mexico
Texas
Wyoming
Nebraska
Kansas
Florida
Hawaii
Montana
Oklahoma
Arizona
Illinois
Missouri
Nevada
North Dakota
Washington, D.C.
Farmer/Rancher
Business
Government
Other
No occupation given"
208
108
91
51
103
TOTAL 561
44
12
10
6
6
5
4
2
2
2
3
1
1
1
1
1
1
TOTAL 102
LMost of the persons in this group were probably farmers/
ranchers, but elected to leave the "Business of Occupation'
line blank.
141
-------
All together, 205 persons took the tour on Friday, and
approximately 150 took the Saturday tours. An extra bus was
also rented to provide an additional tour on Saturday.
Comments from exhibitors were very favorable. One exhibitor
said that other irrigation shows generally do not have the wide
range, scope, and diverse cross-section of equipment and services,
except possibly in California, which was represented at this
show. Letters and phone calls are still continuing to come in
requesting information about the next Irrigation Field Days.
142
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SECTION 9
EVALUATING THE EFFECTIVENESS OF LATERAL SUBSYSTEM IMPROVEMENTS
GENERAL PURPOSE
The measure of effectiveness in irrigated areas most commonly
utilized is irrigation efficiency. Improving water management
practices through structural and operational changes generally
correct such "inefficiencies" as conveyance losses, deep perco-
lation, and field tailwater. However, in terms of controlling
the quality of irrigation return flows, some segments of the
hydrology in the irrigated area are more important than others.
Specifically, if salinity is the major emphasis in a study,
seepage and deep percolation losses will be more important than
field tailwater and conveyance wastes. If sediments are impor-
tant, the reverse would be true. Consequently, the term "irri-
gation efficiency" is too broad. In previous work, the writers
have utilized the terms "conveyance efficiency," "field effi-
ciency," and "application efficiency." Since the definition of
these terms is periodically different from source to source,
care will be given in this section to clearly state the intended
definition.
The effectiveness of the various lateral improvements is
based on the before and after measurements of the various segments
of the irrigation efficiencies noted above. The study was con-
ducted at two levels. First, the lateral inflows and outflows
occurring in measurable locations were monitored to yield a mass
balance estimate of infiltration and evapotranspiration. The
second level involved more detailed examination of representative
fields to provide data to delineate various segments of the on-
farm hydrology. Information from both sources was combined to
develop lateral-by-lateral water budgets. The salinity component
of the analysis is based on previous studies. Equilibrium
salinity concentrations derived from field measurements were
applied to the water flow in order to determine the salt loads in
the respective flows.
The general procedure for evaluating the effectiveness of
lateral improvements involved six steps:
1) measuring lateral inflows and surface wastes;
2) measuring lateral seepage losses;
3) monitoring water uses within the lateral as to
dates and intervals of irrigations;
143
-------
4) irrigation scheduling;
5) evaluation of application efficiencies; and
6) formulation of lateral water budgets.
This list with the exception of the last item has been aggregated
into a single task of evaluating the lateral subsystem hydrology.
The sixth step has been expanded in a separate segment of this
section in order to illustrate the features of the lateral-by-
lateral program.
Cropland Consumptive Use
The importance of evapotranspiration (E^) from crop and soil
surfaces in the Grand Valley was illustrated earlier in the dis-
cussion of the local hydrology. At the farm level, consumptive
use amounts to approximately 39 percent of the field deliveries
and 64 percent of the water infiltrating the soil profile.
Climatological and lysimeter data have been collected for
the three irrigation seasons of the project in an effort to cal-
ibrate and verify various Et estimating procedures. Although
more detailed results of this work are given in a following report,
it is interesting to examine some of these results. The potential
evapotranspiration, Etp , is defined as the evapotranspiration of
a well-watered alfalfa crop with about 20 centimeters of growth.
Five-day mean Etp rates (Figure 57) vary substantially from period
to period, but the average year-to-year variability over the three
years of investigation is less than 10 percent. The Et of indi-
vidual crops, of course, is substantially different from the EfD
values. Table 19 shows the five-day average Et rates for the
1976 irrigation season.
The long-term climatic records for the Grand Valley were
also examined in conjunction with local evapotranspiration esti-
mates. Based upon these data and calculations using the Modified
Penman Equation with locally calibrated coefficients, the average
daily Et values can be expressed as:
Etp-..51 exp-*yA- ..... ,1,
in which,
Etp = average daily potential evapotranspiration rate,
mm/day ,
Day = modified Julian date, March 1=1; and
AD = empirical coefficient, 90 if Day > 137, 120 if Day <_ 137.
Infiltration
During this study, a large number of individual infiltrometer
and advance-recession tests were conducted on the commonly
144
-------
Ul
I
1
11.0
10.0
9.0
8.0
7.0
2 6.0
c
o
I
o
c
0
£
5.0
3.0
2.0
1.0
i I
i i
I
i i i 11
I
i
i i i i
J
5 .5 25 5 15 25 5 15 25 5 15 25 5 15 25 5 .5 25 5 15 25 5 .5 25 5 15 25
Apr May Jun Jul Aug Sep Oct Nov Dec
Figure 57. Potential evapotranspiration, Etp, during the 1974-1976 irrigation season,
-------
TABLE 19. EVAPOTRANSPIRATION IN THE GRAND VALLEY FOR 1976
Period
i
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
Time
Interval
April 1-5
5-10
10-15
15-20
20-25
25-30
May 1-5
5-10
10-15
15-20
20-25
25-31
June 1-5
5-10
10-15
15-20
20-25
25-30
July 1-5
5-10
10-15
15-20
20-25
25-31
August 1-5
5-10
10-15
15-20
20-25
25-31
September 1-5
5-10
10-15
15-20
20-25
25-30
October 1-5
5-10
10-15
15-20
20-25
25-31
EtP
mm/ Day
3.0
3.2
3.4
3.7
4.1
4.15
4.2
8.1
4. 85
5.5
6.25
8.0
9.6
9.8
9.3
8.8
8.3
9.5
10.5
10.3
8,75
8.4
8.1
8.25
9.0
8.6
8.1
7.6
7.7
8.2"
7.5
5.0
6.1
5.25
4.0
4.7
4.5
4.6
4.8
4.5
4.0
2.75
Alfalfa
1.41
2.40
3.40
3.70
4.10
4.15
4.20
8.10
4.85
5.50
6.25
8.00
9.60
9.80
9.30
2.38
4.57
7.79
10.50
10.30
8.75
2.27
4.46
6.77
9.00
8.60
8.10
2.05
4.24
6.77
7.50
5.00
6.10
5.25
4.00
4.70
4.50
4.60
4.80
4.50
4.00
2.75
Et By
Corn
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.97
1.10
1.25
1.76
2.40
2.94
3.26
3.61
3.98
4.28
6.41
7.00
6.48
6.80
6.97
7.51
8.46
8.08
7.94
7.60
7.70
8.09
7.05
4.50
5.12
4.10
2.84
3.15
2.57
2.25
2.02
1.58
1.16
0.66
Crops, mm/Day
Pasture
1.53
2.43
2.96
3.22
3.57
3.61
3.65
7.05
4.22
4.79
5.44
6.96
8.35
8.53
8.09
7.66
7.22
8. 27
9.14
8.96
7.61
7.31
7.05
7.18
7.83
7.43
7.05
6.61
6.70
7.18
6.53
4.35
5.31
4.57
3.48
4.09
3.92
4.00
4.18
3.92
3.48
2.39
Grain
0.54
0.58
0.68
1.00
1.56
2.08
2.60
6.08
4.22
5.28
6.38
8.32
10.08
10.19
9.30
8.18
6.97
6.94
6.51
4.94
2.89
1.51
0.16
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Orchards
1.20
1.28
1.36
1.48
1.64
1.66
2.31
4.46
2.67
3.03
3.44
4.40
7.20
7.35
6.98
6.60
6.23
7.13
9.45
9.27
7.88
7.56
7.29
7.43
8.10
7.74
7.29
6.84
6.93
7.43
5.25
3.50
4.27
3.68
2.80
3.29
2.93
2.99
3.12
2.93
2.60
1.79
146
-------
encountered soil types and cropping patterns in the Valley.
These data and those reported by Skogerboe et al. (1974a) and
Duke et al. (1976) reveal a very large degree of variability.
So much in fact, that specific limits for each major soil type
are difficult to apply. The variability in soil salt content,
previous cultural and farming practices, and cropping patterns
contribute to the uncertainty of representing infiltration char-
acteristics. The infiltration relationship utilized in this
analysis is the Kostiakov Equation:
i = atb (2)
in which,
i = infiltration rate in units of depth per unit time;
t = time in minutes or hours;,
a,b = empirical regression coefficients
The integral of Equation 2 gives the accumulated depth of infil-
tration as a function of time water is applied to the soil:
a tb+1 (3)
t .......... U)
where ,
I = applied depth after t hours in units of length.
The variability in the measured values of a and b is approx-
imately one order of magnitude in each case. However, much of
this variability can be attributed to the effects of previous
irrigations on the soil structure. Examination of infiltration
data for initial irrigations on lands planted to the annual crops
(corn, sugar beets, and grains) resulted in an equation for infil-
tration rate of:
i = 3.13 t-°'6 ......... (4)
in which,
i = infiltration rate in cm/hr; and
t = time of infiltration in hours.
The cumulative depth of infiltration would than be:
I = 7.82 t°'40 ......... (5)
where,
I = infiltrated depth in cm after t hours.
147
-------
A similar examination of infiltration rates during the irri-
gation season and then for perennial crops (pasture, alfalfa,
orchards) has led to the conclusion that these rates might be
related to the expression in Equations 4 and 5. To do this, the
infiltrated depth after 24 hours found in Equation 4 was compared
to similar computations for initial and subsequent irrigations.
Then, a regression fit of the results yielded two relationships
as follows:
and,
in which,
Ir = 0.999 - 0.2245 N + 0.02089 N2 .... (6)
I = 0.3067 + 0.7032/N2 (7)
Ir = relative 24 hour cumulative infiltration; and
N = number of previous irrigations plus 1.
Equation 6 represents the case of perennial crops and Equation 7
the annual crops. To determine the cumulative infiltration rela-
tionship during the irrigation season, Equation 5 is multiplied
by Equation 6 or 7 depending on the crop being irrigated. A
graphical view of Equations 6 and 7 is given in Figure 58.
It may be interesting at this point to demonstrate the pre-
ceding analysis with its numerous assumptions and averaging. If
a typical root zone depletion between irrigations for the annual
crops is 11 centimeters, as data would indicate in the test fields
studied, and a similar value of about 9 centimeters for the annual
crop is assumed, then the application efficiency and deep perco-
lation in the Grand Valley can be determined. In this sense,
application efficiency is defined as the soil moisture requirement
divided by the total infiltrated depth. These results are given
in Table 20 and the time distributed application efficiencies
are shown in Figure 59. in a comparison with field data, one can
expect a substantial variation from these predicted values. How-
ever, in a test of the representativeness of these figures on a
valley-wide basis, the acreages of each crop were multiplied by
the total deep percolation to approximate total deep percolation
losses in the Valley. These results are given in Table 21. As
indicated, about 6,000 ha-m of deep percolation are predicted by
the simplified infiltration analysis. In the previous section on
the Grand Valley hydrology, the valley-wide estimate was approx-
imately 5,000 ha-m. Thus, this analysis overestimates the ear-
lier computation by only about 20 percent, which is quite good
for such a simplistic procedure. It should be noted that the
application efficiencies approach 100 percent in the late seasons
because soil infiltration becomes so limiting that enough water
cannot be put into the root zone. In which case, the crop is
actually in a deficit situation.
148
-------
IO
Perennial Crops
Number of
Irrigations
Figure 58. Relative infiltration rate function for perennial and annual crops in the
Grand Valley.
-------
TABLE 20. SUMMARY OF APPLICATION EFFICIENCIES AND DEPTHS OF
DEEP PERCOLATION FOR A HYPOTHETICAL INFILTRATION
MODEL OF THE GRAND VALLEY
Crop
Alfalfa2
Corn
Sugar
Beets
Irrigation
No.
1
2
3
4
5
6
7
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
I
z.
0.80
0.63
0.50
0.45
0.40
0.40
0.40
1.00
0.48
0.38
0.35
0.33
0.32
0.32
0.32
1.00
0.48
0.38
0.35
0.33
0.32
0.32
0.32
d1
(cm)
22.4
17.6
14.0
12.6
11.2
11.2
11.2
27.9
13.4
10.6
9.8
9.2
8.9
8.9
8.9
36. 91
13.4
10.6
9.8
9.2
8.9
8.9
8.9
Deep
Percolation
(cm)
11.4
6.6
3.0
1.6
0.2
0.2
0.2
21720
18.9
4.4
1.6
0.8
0.2
—
—
-
25.9
27.9
4.4
1.6
0.8
0.2
—
-
-
39.40
Application
Efficiency
%
49
62
79
87
98
98
98
32
67
85
92
98
100
100
100
24
67
85
92
98
100
100
100
Based on 24 hours of irrigation except for first irrigation
of sugar beets (48 hours)
"Figures would also apply to orchards and grass-hay pastures
Figures would also apply to small grains even though they have
about three fewer irrigations.
150
-------
lOOr
50
Alfalfa
Orchards
Pasture
j i L
8 10
u
c
a>
UJ
c
o
o
u
"a.
a.
00
50
• Corn
Small
0
i
2
i
4
1
6
Grains
i
8
i
10
OOr
50
Sugar Beets
8
10
Figure 59.
Irrigation Number
Seasonal distribution of computed application effi-
ciencies for common crops grown in the Grand Valley,
151
-------
TABLE 21. COMPUTED DEEP PERCOLATION IN THE GRAND VALLEY
Crop
alfalfa
corn
orchards
pasture
small grains
sugar beets
Area1
ha
5900
5790
2800
4180
3000
2130
23,800
Deep Percolation
ha-m
1370
1500
650
970
780
740
6010
1976 estimates
In the test area, 13 fields scattered under the various later-
als and growing all of the crops except sugar beets and orchards
were selected to compare with the predicted efficiency values.
Using the above analysis, the number of predicted irrigations
agreed quite well in all cases (within one or two irrigations).
Deep percolation was predicted with ±50 percent accuracy in all
cases except for two alfalfa fields which were substantially under-
irrigated during the entire season. A number of the predictions,
particularly for annual crops, were within approximately the 20
percent figure noted for the Valley. Consequently, in trying to
describe the "typical condition" in the Grand Valley and thereby
derive conclusions as to the effectiveness of various management
alternatives, the preceding analysis should be usable.
Conveyance Seepage and Operational Wastes
Flows diverted from local canals and ditches which are not
available for crop use include four parts:
1) main lateral seepage losses,
2) main lateral wastes or spills,
3) farm head ditch and tailwater ditch seepage, and
4) field tailwater.
Lateral Seepage —
The lateral system in the Grand Valley consists of approxi-
mately 600 kilometers of earthen ditch, the maintenance of which
is generally ignored by both irrigators and irrigation company
officials. In the spring, some efforts are expended to clean
152
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these conveyance systems, but for the most part, they are choked
with weeds and debris. Because most laterals run in the north-
south direction in which gradients range up to 1 to 2 percent,
the poor condition of most laterals is not a serious physical
impediment to the flow of water between the canal and farms.
However, the condition of the laterals does cause high seepage
losses in most cases. Skogerboe and Walker (1972) utilized
inflow-outflow measurements in the test area to determine seepage
losses and arrived at an annual loss rate of 1.3 to 20.3 ha-m/km.
Duke et al. (1976) also evaluated lateral seepage rates in the
Valley and found approximately the same range of seepage rates.
An average annual seepage rate of 8.8 ha-m/km annually is thought
to represent the typical lateral in the Valley. Thus, valley-
wide lateral seepage losses amount to the estimated 5,300 ha-m
per year given earlier.
Inflow-outflow tests were repeated in the laterals included
in this study during the first year of the study. These data
average slightly less than the 8.8 ha-m/km noted above for all
but two of the laterals studied; for the laterals numbered GV 160
and GV 95, seepage rates were about double the Valley average
estimate.
Lateral Operational Wastes —
Because of the abundant nature of the normal water supply in
the Grand Valley, many laterals with more than two to four users
will operate continuously. The flow during periods of non-use
will be simply wasted into a nearby drain or wasteway. The mag-
nitude of these wastes has not been measured and reported in the
Grand Valley; therefore, comparison of this project's data with
that of others cannot be made. Field tailwater is very often
dumped directly back into the lateral channel (in fact, a number
of water rights have been established for this situation and some
irrigators use tailwater almost exclusively). Lateral wastes are
essentially impossible to delineate. For most purposes, the vol-
ume of operational wastes can be determined by subtracting field
tailwater from the total surface outflow.
Head and Tailwater Ditch Seepage —
For most crops grown locally, the intervals between irriga-
tions will range from about three weeks early in the season to
seven to ten days during the peak demand periods. Many fields
are irrigated in three to five sets so that field head ditches
carry water on the order of 50 percent of the time. Tailwater
ditches would carry water about one-half as often as the head
ditches, but in substantially less volumes. Seepage from tail-
water ditches can be ignored without significant error. Current
estimates of seepage from head and tailwater ditches are based on
lateral measurements, even though the head ditch flow rates are
usually much smaller than those found in the lateral. Estimates
by the writers in previous work have indicated these seepage
losses to be approximately 1 to 2 ha-m/km each year. Thus, the
153
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1,300 kilometers of unlined head ditches and an almost equal num-
ber of tailwater ditches lose about 2,500 ha-m through seepage
each year. This is approximately 30 to 35 percent of the total
on-farm contributions to the groundwater.
Field Tailwater —
A number of studies (Duke et al., 1976 and Skogerboe et al. ,
1974a) have measured field tailwater to be from 34 to 43 percent
of the water applied to each field. For the 13 fields isolated
during the course of this study, tailwater volumes were as high
as 60 percent of the applied water. The majority of fields in
the test area, however, are within the 34 to 43 percent limits.
If these field tailwater percentages are extended to the entire
Grand Valley, field tailwater volumes would range from 11,300 ha-m
(34 percent) to 16,000 ha-m (43 percent). In budgeting the water
flows in the Valley, the tailwater, canal, and lateral spillage
were residual calculations. Consequently, total conveyance spills
would be reduced from 25,700 ha-m (34 percent field tailwater) to
21,000 ha-m (43 percent field tailwater). Total farm deliveries
would therefore change from 34,300 ha-m (34 percent) to 39,000 ha-ni
(43 percent).
Irrigation Scheduling
Previously reported irrigation scheduling studies in the
Grand Valley have indicated a comparatively small impact on irri-
gation efficiencies (Skogerboe et al. , 1974a). Nevertheless,
irrigation scheduling was initiated as part of this study on
selected fields under each lateral. The fields in the study area
were divided into two groups. The first group consisted of fields
on which the spectrum of irrigation scheduling technology was
applied, except that the irrigator was not given the scheduling
recommendations. The scheduling data were then compared with the
irrigation practices of individual irrigators in order to estimate
the impact of the irrigation scheduling service if it had been
provided to the farmer. The second group was advised of the
irrigation scheduling recommendations. Data from these fields
indicated the acceptability of the scheduling service to local
farmers through comparison of recommended versus actual irrigation
practices.
The procedures utilized in this study were similar to the
irrigation scheduling methodology practiced throughout the western
United States by both private and governmental services. Daily
data were collected to identify the surface water balance, soil
moisture deficits, and irrigation efficiencies. Evapotranspira-
tion estimates and scheduling recommendations were supplied by
the Bureau of Reclamation as part of their on-going local program.
Project personnel transmitted the information directly to indi-
vidual irrigators and spent substantial time explaining the basic
procedures, flow measurement, and soil-water-plant relationships.
154
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An essential tool for any irrigator is the ability to peri-
odically determine the amount of moisture in the soil. Many
farmers estimate the need for water by the plant color, while
others use a shovel to observe the top 6 inches of the soil pro-
file. For the purposes of "scientific irrigation schedule" up-
dating, methods which yield more reliable data on the water
available throughout the root zone are used. Many methods are
available for this purpose varying in simplicity, cost, and per-
formance. The typical procedure for each method is to measure
the soil moisture at one foot intervals through the depth of the
root zone. Three methods were compared to test their potential
for use in scheduling: (a) the oven-dry or gravimetric method;
(b) the carbide reaction "SPEEDY" soil tester; and (c) the "feel"
tests.
The oven-dry test involves drying soil samples at 105 degrees
C and comparing the dry weight against the wet weight of the
original sample. The soil moisture present is then determined
by multiplying by the soil bulk density.
The carbide method is based on measuring the amount of gas
produced when a moist soil sample is mixed with calcium carbide.
A 26-gram soil sample is mixed with calcium carbide in an enclosed
container where the gas production is indicated on a pressure
gauge. This reading is converted to percent moisture through a
chart provided with the instrument. While the time required for
each test is only 1 to 3 minutes, cleaning the canister and pre-
paring the samples requires another 30 minutes for a 4-foot set
of samples. This is a good field technique when answers are
needed in a short time.
The feel test is a method of estimating soil moisture by
noting certain characteristics about the soil. The ability for
the soil to be "balled" on the palm of the hand, "ribboned"
between the thumb and the forefinger, or by noting "free water"
on the soil sample allows the tester to make estimations of the
amount of moisture present. The feel test is quick and easily
applied, but it is affected by different soil types and by the
tester who tends to be influenced by past events such as previous
irrigations and subconscious ideas of what is expected to be
present.
All soil moisture testing for the purpose of updating irri-
gation schedules was done gravimetrically. Additionally, 341
samples were feel tested and 76 were tested with the carbide test
method to determine the potential for these methods to be used
in the future. All tests were taken as the percent moisture on
a dry-weight basis. Using the oven-dry moisture content as the
basis for comparison, each measurement was expressed as a differ-
ence between the oven-dry content and the feel test content and/
or the oven-dry content and the carbide test content. A graph
155
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of the range of differences with respect to the number of tests
is shown in Figure 60.
Over the period of the study, there was only slight improve-
ments in the accuracy of the feel estimation technique. These
should not be attributed to an improvement in estimating the con-
tent, but rather to experience in noting changes, through the
depth of the root zone. The greatest difficulty with the feel
method is the ability to differentiate between soil types. The
potential for improvement lies in the skill required to determine
soil types and use this to reference the moisture holding capacity.
The results of the irrigation scheduling efforts substantiate
earlier studies. With the exception of three cases, the irriga-
tion scheduling service did not significantly affect irrigation
efficiencies. A comparison of recommended versus actual irriga-
tions indicated that the computer predictions were generally
within two days of an actual irrigation, regardless of whether or
not the irrigator was informed of the recommendations. Thus, the
timing of irrigations by either farmer judgment or computer pre-
diction was not significantly different. Further, it appears
that recommendations have little effect on irrigator decisions
when substantial changes are not being recommended. Studies else-
where have indicated gradual farmer acceptance. The largely
insignificant impacts of this irrigation scheduling study may be
partially due to the short interval of the investigation.
Irrigation scheduling did not significantly impact the depth
of water applied by the individual irrigators. The mid to late
season infiltration rates are comparatively small in the Grand
Valley, so the soil itself acts as the system control. Irrigators
tend to maintain fixed set times rather than vary the set time to
achieve a desired depth of application. The major benefits to be
derived from irrigation scheduling would be in conjunction with
flow measurement to specify the amount to be applied.
The three exceptions noted previously are interesting. In
two cases, the method of irrigation was changed to a sprinkler
system with which the irrigator had not had previous experience
or preconceived concepts. In these situations, the scheduling
recommendations were well received and implemented. The third
exception was an irrigator with no previous furrow irrigation
experience. Again, the recommendations were followed closely.
These experiences lead to the conclusion that irrigation schedul-
ing in the Grand Valley is seriously limited by reliance on past
customary practices. Where new systems are constructed, irriga-
tion scheduling can be more easily implemented.
156
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50
40
30
w 20
o
h.
k.
UJ
10
0)
a.
E
o
V)
»- O
-
-
-
-
i
_ ,
i
—
|
|
F
eel Test
P"! r— »
Q)
-O
E
20
10
Carbide Method
<-4.5 -3.5 -2.5 -1.5 -0.5 0.5 1.5 2.5 3.5 4.5 >5.5
Deviation of Moisture Percentages from Oven-Dry Values
Figure 60.
Differences in the estimation of the percent
moisture between the feel test and the oven-dry
value and the carbide test and the oven-dry value,
157
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EVALUATING LATERAL IMPROVEMENTS
A complete listing of the field and laboratory data accumu-
lated during this project's three years of investigation is
beyond the scope of this report. Even lateral-by-lateral
summaries represent a large number of pages which make it diffi-
cult to easily interpret the results. Condensed water budgets
have been developed for each lateral for conditions before and
after the lateral improvements. The cropping and climatological
conditions were those which occurred during the 1976 irrigation
season. Since this method of analysis involves substantial
manipulation of the yearly data, it is probably useful to
briefly describe these procedures before examining the effects
under the individual laterals.
Evaluation Procedure
Prior to the lateral improvements, data were collected on
inflows and outflows, field lengths, slopes, crops, soil char-
acteristics, infiltration rates, and climatological information.
Routine observations in the test area identified the dates, set
intervals and frequencies of irrigations on the fields under
each lateral subsystem. This same field data collection proce-
dure was followed after the installation of lateral improvements;
however, the effect was intensified because of the irrigation
scheduling studies. Throughout the course of the investigation,
Carious short-term studies, like seepage loss rates, were
conducted.
The purpose of the data collection was to develop mass
balance resolution of the water and salt flows under each lateral
turnout. A comparison of these budgets before and after the
construction yielded the measured effectiveness of the individual
improvements. Local crop rotation patterns and the periodic
practice of idling a field for a season create a masking vari-
ation. To overcome this difficulty, the approach taken in the
analysis was to transform the results of the preconstruction
studies to the postconstruction pattern and irrigation schedule.
This process is largely a matter of adjusting on-farm budgets.
Seepage rates in the unlined laterals, head ditches, and tail-
water ditches were assumed constant from year to year.
The mass balance of water in the field area consists of
inflows through the head ditch and precipitation, while the out-
flows consist of deep percolation, tailwater runoff, and evapo-
transpiration. It was also assumed (with justification) that the
general irrigation practice followed by each irrigator remained
the same on respective fields and crops from year to year.
Then to transform the preconstruction hydrology to the post-
construction conditions, the following procedure was used.
First, the irrigation schedules for the individual fields and
crops were recomputed using 1976 climatological data. Then the
158
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volumes of infiltration, deep percolation, and tailwater were
determined. Summing these figures yielded the estimated farm
deliveries which would have occurred in 1976 if the improvements
had not been made. Once the flows had been reconciled with 1976
conditions, they were condensed by summing over the irrigation
season to yield an annual mass balance for each lateral subsystem.
The salinity segment of the budgets was imposed on the annual
water budget to determine the annual transport of salts.
The effectiveness of the lateral improvements in total was
established with the aid of two main assumptions. The first of
which is that the actual salinity impact was due to a reduction
in the flow of water to the groundwater where the salt pickup
mechanism would act. In the test area, the salt pickup rate
noted previously was estimated to be 77.8 metric tons/ha-m. Of
the flows entering the groundwater basin, about 44 percent are
consumed by phreatophytes. Secondly, the small effect of the
open ditch drainage system was assumed to be negligible.
The values of seepage losses from laterals, head ditches,
and tailwater ditches were summed with deep percolation losses
to give the annual subsurface return flows before and after the
lateral improvements. The difference was multiplied by 43.57
(which is equal to [(1-0.44) x 77.8)1 to determine the^estimated
salt loading reduction resulting from the improvements. To relate
the benefits of this reduction to the costs expended during the
project, the salt reduction was multiplied by $150 per metric ton
and then divided by the lateral costs. This pseudo benefit-cost
ratio is intended as a point of interest relative to the salinity
control benefits of the project. The downstream damages of $150
per metric ton were derived from recent estimates of the salinity
related detriments in the Lower Colorado River Basin and will be
more fully developed in a subsequent report. It should be noted,
however, personal communication with researchers in the Lower
Colorado River Basin indicates that downstream detriments may be
two to three times this figure if intermediate results are correct.
Field relief drainage was included in this study to evaluate
the utility of intercepting deep percolation before reaching a
higher equilibrium salinity concentration. Results of an earlier
drainage study (Skogerboe et al. , 1974b), indicated the intercepted
drain flows would have approximately 3,000 mg/1 less salinity
than the groundwater, thus effecting substantial water quality
improvements. This particular drainage system continued to be
monitored throughout this project. The results, which were pre-
dicted by Skogerboe et al. (1974b) show a three to five year
convergence on salinity values encountered at the bottom of a
well-drained soil profile. In this study the impact of drainage
has been included on the basis of water quality expected after
accumulated salts have been removed and the system has become
similar to lands not requiring relief drainage. Relief drainage
would be expected to reduce salt loading to about 39 percent of
159
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that of the irrigation water. Because of low hydraulic conduc-
tivity and saline conditions of the soils, the drainage systems
have been intercepting approximately 15 percent of the deep per-
colation at the 12 meter spacing. This rate is assumed indirectly
proportional for other spacings.
Evaluation of Lateral HL C
The lands served by HL C were not improved in terms of
either lateral linings or on-farm improvements. The project did
participate in converting an open-ditch drain to a buried con-
crete line in order to consolidate two fields and make irrigation
more convenient. The only emphasis of the project beyond this
small improvement was irrigation scheduling. The consolidation
of the two fields did, however, result in the elimination of 225
meters of unlined head ditches.
Analysis of data into the 1976 based annual summary shown
in Table 22 indicated no significant impact on return flows due
to irrigation scheduling alone.
TABLE 22. ANNUAL HYDROLOGIC SUMMARY FOR LATERAL HL C ADJUSTED
TO 1976 CONDITIONS (ALL UNITS IN HECTARE-METERS)
Water Budget Category
Before Lateral
Improvements
After Lateral
Improvements
Total lateral Diversions
Seepage
Operational Wastes
Farm Deliveries
Total
Total Farm Deliveries
Seepage
Tailwater
Consumptive Use
Deep Percolation
Total
Total Lateral Return Flows
Surface Return Flows
Subsurface Return Flows
Total
4.53
0
15.82
20.35
2.40
8.06
4.50
0.86
15.82
8.06
7.79
15.85
2.55'
1.98
15.82
20.35
2.40
8.06
4.50
0.86
15.82
10.04
5.81
15.85
Reduction in Salt Loading 11.1 m tons/year
Downstream Benefit $16,650/year
Actual Cost $ 4,860
Benefit-Cost Ratio 3.43
Reduced by elimination of 225 m of unlined head ditches.
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Evaluation of Lateral HL E
Lateral HL E represents a substantial departure from the
other study laterals in the sense that these lands are already
well managed with substantial improvements already in place. For
example, none of the head ditches and only 33 percent of the lat-
eral was unlined at the beginning of this project. Improvements
to this system involved conversion of 5.2 hectares of orchard to
overhead solid-set sprinklers and 792 meters of piped lateral.
Table 23 illustrates the before and after water budgets and
economic impacts on the HL E system. The sprinkler system reduced
TABLE 23. ANNUAL HYDROLOGIC SUMMARY FOR LATERAL HL E ADJUSTED
TO 1976 CONDITIONS (ALL UNITS IN HECTARE-METERS)
Water Budget Category
Before Lateral
Improvements
After Lateral
Improvements
Total Lateral Diversions
Seepage
Operational Wastes
Farm Deliveries
Total
Total Farm Deliveries
Seepage
Tailwater
Consumptive Use
Deep Percolation
Total
3.42
5.15
73.93
82.50
0
31.79
34.00
8.14
73.93
0
30.25
52.25
82.50
0
10.99
34.00
7.26
52.25
Total Lateral Return Flows
Surface Return Flows
Subsurface Return Flows
Total
36.94
11.56
48.50
41.34
7.26
48.60
Reduction in Salt Loading
Downstream Benefit
Actual Cost
Benefit-Cost Ratio
188 m tons/year
$28,200
$30,760
0.92
deep precolation losses under the entire lateral by nearly 0.9 ha-m
with another 3.4 ha-m reduction derived from the lateral linings.
The benefit-cost ratio is the lowest of the project (0.92). It
might, therefore, be concluded that expenditures on well-managed
farming units will have less impact in terms of salinity control
than investments into less well-operated systems. However, the
irony of the situation is that the better farm managers are more
willing to make improvements and change methods.
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Evaluation of Lateral PD 177
The designation of the lands included in the project as
Lateral PD 177 is somewhat misleading in the sense that only the
lower lands of the lateral were actually involved. This is noted
because the lateral system up to the beginning of these lands
was lined as part of the earlier CSU investigations funded by
EPA. These earlier improvements amounted to 1,100 meters of con-
crete linings. In terms of water control at the inlet to these
lands, this is the only lateral considered where inflows were not
controlled. The hydrology under PD 177 is shown in Table 24.
Measurements indicated that 60.5 ha-m entered this part of
the system during 1976 of which only 20.56 ha-m (34 percent) were
actually delivered to the fields. The installation of a buried
pipeline lateral system essentially eliminates the 16.7 ha-m of
seepage that occurred during the preproject period. A trickle
irrigation system on 2.2 hectares of orchards was responsible
for reducing deep percolation by nearly 50 percent under the
lateral. This savings, along with 1.2 ha-m reduction in head
ditch seepage through concrete linings and conversion to aluminum
gated pipe, resulted in a total impact of 800 metric tons per
year decline in salt loading attributable to this lateral. The
benefit-cost analysis shows a respectable value of 2.77.
Evaluation of Lateral GV 92
The only improvements made on the GV 92 system were the con-
crete lining of 189 meters of lateral and the conversion of 817
meters of the same lateral to buried plastic pipeline. Seepage
tests indicated that these linings would reduce seepage loss by
8.84 ha-m annually. Salt loading reductions would, therefore,
be 385 metric tons per year for a benefit of $57,800. Since the
project expenditure for the GV 92 improvements was $13,600, the
ratio of benefits to costs is approximately 4.25.
Evaluation of Lateral GV 95
The area served by the GV 95 turnout from the Grand Valley
Canal is the largest included in the project (70 ha). The funds
spent for improvements were also the largest ($104,788.80). This
lateral is also of interest in another respect. A great deal of
the available water supply throughout the system is returned
tailwater and wastes from adjacent laterals. For instance, in
the 1976 season, about 36 percent of the available water came
from these miscellaneous sources.
The GV 95 lateral is typical of many of the larger systems
throughout the Grand Valley. Total diversions (including miscel-
laneous surface inflows) during the 1976 irrigation season were
about 170 ha-m. Prior to the lateral linings, about 27 ha-m or
16 percent of the flows would be lost from the system by seepage.
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TABLE 24. ANNUAL HYDROLOGIC SUMMARY FOR LATERAL PD 177 ADJUSTED
TO 1976 CONDITIONS (ALL UNITS IN HECTARE-METERS)
Water Budget Category
Before Lateral
Improvements
After Lateral
Improvements
Total Lateral Diversions
Seepage
Operational Wastes
Farm Deliveries
Total
Total Farm Deliveries
Seepage
Tailwater
Consumptive Use
Deep Percolation
Total
Total Lateral Return Flows
Surface Return Flows
Subsurface Return Flows
Total
16.66'
19.79
24.05
60.50
4.09
10.34
7.00
2.62
24.05
30.13
23.37
53.50
0
39.94
20.56
60.50
2.91
8.84
7.00
1.81
20.56
48.78
4.72
53.50
Reduction in Salt Loading
Downstream Benefit
Actual Cost
Benefit-Cost Ratio
800 m tons/year
$121,900
$ 43,970
2.77
Approximately 1.1 km of concrete lining had been accomplished
prior to this project under EPA funding (Skogerboe and Walker,
1972). These linings reduced seepage by about 9.7 ha-m/year
resulting in a salt reduction of 421 tons annually. In 1976
this lining would have cost approximately $17,600. Recomputing
the figures given above then:
Reduction in Salt Loading
Downstream Benefit
Actual Cost
Benefit-Cost Ratio
1,231 m tons/year
$184,650
$ 61,570
3.00
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This project essentially eliminated these losses. However the
additional water available in the lateral through the seepage
savings, the more equitable allocation due to flow measurement
and the faster travel times resulted in about 26 ha-m which were
simply wasted in 1976. This figure is approximately equal to
previous seepage losses. Such wastes will diminish once the local
irrigators become more accustomed to the operation of the lateral.
Head ditch linings, conversion to gated pipe, and a change
to a side-roll sprinkler system eliminated all but 0.27 ha-m of
a previous head ditch seepage loss of slightly more than 5 ha-m/
year. These savings were applied to the cropped surface in 1976
in the form of larger furrow streams, or added furrows within an
irrigation set- The tightness of the soils, however, prevented
significant increases in deep percolation. As a result, field
tailwater volumes after the improvements were increased over
prior conditions. These flows could also be expected to decrease
as irrigators adjust to the added water supply.
A reduction in deep percolation and head ditch seepage amount-
ing to approximately 0.5 ha-m annually was achieved under GV 95
with the conversion of a 4 hectare hay field from the typical
turrow irrigated system to a side-roll sprinkler system. Uni-
rormity and efficiency measurements indicated that deep perco-
lation losses were reduced from approximately 23 centimeters each
year to 13 centimeters, primarily on the basis of reduced appli-
cation during the early irrigation season. Replacement of head
ditches resulted in another 0.1 ha-m reduction in groundwater
additions. For this field, seasonal application efficiency was
improved from 77 percent to 87 percent, a change of only 10 per-
cent, but nevertheless a significant impact on the volume of deeo
percolation. H
A summary of the GV 95 hydrology is given in Table 25. The
efforts and expenditures of this project reduced salt loading
?°? !r™ conveyance network and croplands under the GV 95 lateral
by 1,400 metric tons for a benefit of $210,100. The benefit-cost
ratio for this lateral is computed to be 2.0 to 1. A 6-hectare
drainage system (24 meter spacing) under this lateral intercepted
approximately 0.10 ha-m of deep percolation in 1976, therebv
reducing the GV 95 salt load by an additional 2.8 metric tons per
ye,ar.
Evaluation of Lateral GV 160
Other than 11.5 hectares of field relief drainage, the manor
improvements under the GV 160 system were lateral and head ditch
linings. This lateral represented the poorest conditions of
lateral maintenance found in the test area. Seepage tests indi-
cated loss rates almost double the values encountered elsewhere
In addition, local irrigators had constructed two closely located
laterals (GV 160 and GV 161) which could be consolidated to
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TABLE 25. ANNUAL HYDROLOGIC SUMMARY FOR LATERAL GV 95 ADJUSTED
TO 1976 CONDITIONS (ALL UNITS IN HECTARE-METERS)
Water Budget Category
Before Lateral
Improvements
After Lateral
Improvements
Total Lateral Diversions
Seepage
Operational Wastes
Farm Deliveries
Total
Total Farm Deliveries
Seepage
Tailwater
Consumptive Use
Deep Percolation
Total
Total Lateral Return Flows
Surface Return Flows
Subsurface Return Flows
Total
26.81
0
142.69
169.50
5.11
55.35
57.50
24.73
142.69
55.35
56.65
112.00
0
25.64
143.86
169.50
0.27
61.86
57.50,
24. 23'
143.86
87.50
24.50
112.00
Reduction in Salt Loading
Downstream Benefit
Actual Cost
Benefit-Cost Ratio
1,403 m tons/year
$210,450
$104,790
2.01
Includes approximately 0.10 ha-m intercepted by the relief
drainage system.
<2
Includes 60 ha-m of inflows from adjacent laterals (wastes and
tailwater).
further reduce seepage losses. Thus, the program for the GV 160
lateral was largely one of controlling seepage through linings
and lateral consolidation.
Table 26 illustrates the before and after hydrology for
lateral GV 160. More than 4,200 meters of lateral were either
lined with concrete or converted to a buried plastic pipeline.
Another 900 meters of previously used lateral were eliminated
completely by including its lands under the GV 160 system. The
total effect of these linings thereby eliminated more than 82 ha-m
of seepage losses which would contribute almost 3,600 metric tons
annually to the Colorado River system. Another 232 meters of
field head ditches were lined with savings of about 0.5 ha-m in
seepage losses. A relief drainage system installed under 11.5
hectares of GV 160 cropland would intercept about 0.13 ha-m of
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TABLE 26. ANNUAL HYDROLOGIC SUMMARY FOR LATERAL GV 160 ADJUSTED
TO 1976 CONDITIONS (ALL UNITS IN HECTARE-METERS)
Water Budget Category
Before Lateral
Improvements
After Lateral
Improvements
Total Lateral Diversions
Seepage
Operational Wastes
Farm Deliveries
Total
Total Farm Deliveries
Seepage
Tailwater
Consumptive Use
Deep Percolation
Total
Total Lateral Return Flows
Surface Return Flows
Subsurface Return Flows
Total
86.40
26.14
121.46
234.00
10.46
52.23
49.00
9.77
121.46
78.37
106.63
185.00
4.29
108.71
121.00
234.00
10.46
52.23
49.00,
9.77'
121.46
160.94
24.06
185.00
Reduction in Salt Loading
Downstream Benefit
Actual Cost
Benefit-Cost Ratio
3,600 m tons/year
$539,600
$ 84,680
6.37
Includes 0.13 ha-m/year intercepted by drainage system.
Includes an estimated 60 ha-m inflow from adjacent lateral
subsystems.
deep percolation annually, and thus reduce salt loading bv 3 5
metric tons per year.
The total reduction in groundwater additions by the GV 160
lateral was 82.57 hectare-meters per year, which converts to a
salinity reduction of 3,600 metric tons at a benefit of more
than one-half million dollars annually. The expenditures on
this system were nearly $85,000 which indicates a benefit-cost
function of about 6.4 to 1. The results for this lateral clearly
demonstrate the advantages of selecting the most severe salt
contributors for first attention in a salinity control program.
Evaluation of Lateral MC 3
The MC 3 lateral is a single user system consisting of 3
hectares of land which had been abandoned prior to this project
due to soil salinization from a high water table. A field
relief drainage system under 2.5 hectares of the land coupled with
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installation of 157 meters of concrete head ditch linings were
the improvements made under this lateral. The head ditch was
designed as an automatic cut-back system, but was not utilized
as such by the landowner. In fact, the land was not irrigated
during this project and has since been sold. The effectiveness
of these improvements cannot be determined.
Evaluation of Lateral MC 10
The annual water mass balance for Lateral MC 10 is given in
Table 27. Measured inflows during the 1976 irrigation season
totaled 91 ha-m of which 72 percent, or 66 ha-m were delivered
to the respective fields. Seepage losses in the lateral system
TABLE 27. ANNUAL HYDROLOGIC SUMMARY FOR LATERAL MC 10 ADJUSTED
TO 1976 CONDITIONS (ALL UNITS IN HECTARE-METERS)
Water Budget Category
Before Lateral
Improvements
After Lateral
Improvements
Total Lateral Diversions
Seepage
Operational Wastes
Farm Deliveries
Total
i
15.92X
20.00
73.08
109.00
0
35.92
73.08
109.00
Total Farm Deliveries
Seepage
Tailwater
Consumptive Use
Deep Percolation
Total
Total Lateral Return Flows
Surface Return Flows
Subsurface Return Flows
Total
9.05
25.73
29.00
9.30
73.08
45.73
34.27
80.00
1.74
33.34
29.00
9.002
73.08
69.26
10.74
80.00
Reduction in Salt Loading
Downstream Benefit
Actual Cost
Benefit-Cost Ratio
1,027 m tons/year
$157,050
$ 68,540
2.25
10.09 ha-m intercepted by 6.1 ha of field relief drainage
results in a salinity savings of an additional 2.39 m tons/year,
396 m of this lateral were lined prior to this project.
167
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were negligible due to 100 percent lining (with PVC pipe and slip
form concrete) of the 2.6 kilometers of lateral channel. Seepage
from farm head and tailwater ditches was estimated at 1.7 ha-m
after the lining of all but 871 meters of head ditches (76 per-
cent) . None of the tailwater ditches were lined under the lateral,
Deep percolation losses were reduced to approximately 9 ha-m. A
large portion of this reduction is due to the installation of an
automatic cut-back furrow irrigation system. The drainage systems
installed under this lateral did not significantly impact the MC
10 hydrology, primarily because it was installed under the field
irrigated by the cut-back system. The drainage system intercepted
approximately 0.09 ha-m during the 1976 irrigation season, reduc-
ing salt loading by 2.39 metric tons. Total subsurface return
flows thus amounted to 10.7 ha-m, which contributed 470 metric
tons of salt to the river annually.
Prior to the lateral improvements, total seepage losses were
determined to be about 25 ha-m per year and deep percolation
losses were 9.3 ha-m/year, totaling about 34 ha-m annually. The
lateral improvements thereby resulted in a decreased groundwater
contribution of 23.5 ha-m per year, which translates to 1,000
metric ton per year reduction in salt loading. This salt reduc-
tion reduces downstream detriments by more than $150,000 each
year and was achieved at a local cost of only 45 percent of the
damage figure. This is a more than two to one benefit-cost ratio.
Irrigation efficiencies as described by field efficiency
(percentage of farm deliveries utilized as consumptive use) and
application efficiency (percentage of farm deliveries minus tail-
water utilized as consumptive use) changed from 40 percent to 44
percent and 61 percent to 73 percent, respectively. It is evi-
dent that lateral and head ditch linings result in more available
water with which to irrigate under this lateral, but the excess
is primarily wasted directly back to the river. This condition
results from two factors. First, the excessive water supply to
the Grand Valley means that MC 10 irrigators were already receiv-
ing an adequate water supply even with the seepage losses. And
secondly, the soil infiltration rates act as a control on infil-
tration into the root zone. Higher furrow flow rates have rel-
atively small overall impacts on infiltrated soil moisture depths
as compared to the time water runs in the furrows; and therefore,
higher furrow flow rates simply result in more tailwater losses.
Evaluation of MC 30
MC 30 is a single user lateral included in a previous drain-
age study. Under this project, the entire lateral and head ditch
length were lined with slip form concrete. One field was divided
into two separately irrigated areas to achieve better uniformity
of water applications. The lateral does not have significant
tailwater ditches since these flows exit immediately into nearby
drainage channels. A drainage system under approximately one-half
168
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of the cropped area is considered separately since it was instal-
led prior to the initiation of this project.
During the 1976 irrigation season, 36.2 ha-m of water were
delivered into the MC 30 lateral, all of which was applied to the
fields. Seepage losses from the 942 meters of head ditch and 415
meters of lateral were essentially eliminated by the linings.
Of the flows, 17.5 ha-m ran off the fields as tailwater (48 per-
cent), 15.50 ha-m were used by the crops (43 percent), and 3.2
ha-m percolated below the crop root zone (9 percent). The leach-
ing fraction for the two fields averaged 17 percent.
Prior to these improvements and under 1976 conditions,
approximately 3.26 ha-m of the diversions would have been lost
through lateral and head ditch seepage. These seepage losses
would have resulted in a salt pickup of some 142 metric tons
annually. The economics associated with this lateral's salinity
control program, therefore, are 142 metric tons of salt eliminated
from the Colorado River system annually at a cost of $8,685.
Downstream benefits are expected to be more than $21,000 per year
for a benefit-cost ratio of 2.45 to 1.
A summary of the before and after annual mass balances for
irrigation diversions into the MC 30 lateral is given in Table 28.
SUMMARY
It is interesting to combine the impact of this project with
improvements made previously with EPA support in the test area.
Skogerboe and Walker (1972) evaluated a lateral and canal lining
effort responsible for a 4,200 metric ton per year reduction to
the Colorado River. Improvements constructed in this project
accumulate to an 8,100 metric ton per year reduction. Together,
these improvements represent 22 percent of the salt loading
attributed to this area by Skogerboe and Walter (1972). Actual
designated construction costs for these improvements total $350,
000 (1972 base) for the earlier project and $378,000 (1976 base)
for this one. Also, $17,000 was spent for the previous drainage
installation under Lateral MC 30. Consequently, 12,300 metric
tons have been removed from the Colorado River system at a cost
of $745,000. If downstream detriments amounted to only $60 per
ton of salt, these improvements in the aggregate would have been
feasible. Given the $150 per ton damage figure, however, this
combined local improvement yielded a benefit-cost ratio of 2.50
to 1. The numerous benefits to local agriculturalists have not
been included. Walker (1975) evaluated the business multipliers
in the Grand Valley associated with irrigated agriculture. A
weighted average multiplier of 1.75 follows from that work, which
would thereby raise the above noted benefit-cost ratio of 4.25 to
1. Other benefits (i.e., increased crop production) could be
added, if known.
169
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TABLE 28. ANNUAL HYDROLOGIC SUMMARY FOR LATERAL MC 30 ADJUSTED
TO 1976 CONDITIONS (ALL UNITS IN HECTARE-METERS)
Water Budget Category
Before Lateral
Improvements
After Lateral
Improvements
Total Lateral Diversions
Seepage
Operational Wastes
Farm Deliveries
Total
Total Farm Deliveries
Seepage
Tailwater
Consumptive Use
Deep Percolation
Total
Total Lateral Return Flows
Surface Return Flows
Subsurface Return Flows
Total
2.45
0
33.75
36.20
0.81
14.24
15.50,
3.20
33.75
14.24
6.46
20.70
0
17.50
15.50
3.20
36.20
Reduction in Salt Loading
Downstream Benefit
Actual Cost
Benefit-Cost Ratio
142 m tons/year
$21,305
$ 8,686.03
2.45
A previous field drainage installation costing approximately
$17,000 was installed on 4 ha of grass hay. Drain outflows
indicate an annual flow of about 0.14 ha-m which has a salt
load reduction equivalent of 3.7 m tons/year. The individual
drainage benefit-cost ratio is therefore 0.03. For all of the
EPA sponsored improvements on this lateral, this benefit-cost
ratio is 0.57.
These cost-effectiveness figures, of course, represent an
aggregate view of the salinity control feasibility in the Grand
Valley. Of possibly more interest is the respective feasibility
of the various alternatives for reducing salt loading. These
might best be expressed in dollars per annual metric ton of salt
reduction as shown in Table 29. Canal lining and desalting feas-
ibilities are discussed by Walker (1977) and only a general con-
sideration will be given herein. The cost-effectiveness values
given in Table 29 are generally lower than figures reported by
Walker (1977) primarily because various overhead costs have not
been included (i.e., design, specifications, contract negotiations,
etc.). It is interesting to consider these individual alterna-
tives in a general sense and also include others that might be
applied.
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TABLE 29. SUMMARY OF COST-EFFECTIVENESS ASSOCIATED WITH INDIVIDUAL LATERAL SALINITY
CONTROL ALTERNATIVES IN GRAND VALLEY1
Improvement Cost-Effectivonoss S/annual ton
Lateral
No.
HL C
HL E
PD 177
GV 92
GV 952
GV 160
MC 10
MC 30
Slip
Concrete
Lateral
—
—
42
49
20
10
52
68
Form
Linings
Head Ditch
—
—
72
—
88
98
195
68
PVC Pipe
Lateral Linings
—
17
36
32
29
12
33
71J
Gated Pipe
Head Ditch
Linings
—
—
59
—
93
--
68
253
Automation
Cut-back
Sprinkler Drip Furrow
Irrigation Irriaation Irriqation
—
464
308
—
257
—
82
—
Field Relief
Drainage
438
—
—
—
18,000
7,017
7,070
4,600
Total
For
Lateral
438
164
50
35
75
24
67
176
''"MC 3 was not incuded because no direct cost-effectivonoss analysis could be made.
2Some tailwater ditches were lined with concrete (S327/ton) and pipe ($722/ton).
3Added to existing system to provide better irrigation uniformity.
-------
Conveyance Channel Linings
crete or PVC plastic irrigation pipe. The
E^-ss.-a«B-82 JJSL a
Canal
ing costs based on information developed locals x
Q97h Reclam?tion »ere analyzed and reported by WalJer **
(1977) The marginal cost-effectiveness of canal linina *««, •
Smalf nr A f96. wa\less feasible than canal lining. in those
tChef,Where seePa5e rat^s are compari
would exhibit its most favorable cost
^e.lateral system can be lined with either concrete slin
gS'°f PVC PipS Wlth Uttle °r no ^onomic difference
circumstances would dictate such decisions. Laterals
woud \^Verfal "F^a^s wiH operate almost continually an?
later^o ?ref°re/ have hi^her seepage losses than single user
" a '
s .s u
than for the almost exclusive contractor requirement of rnn
linings. And finally, pipelines tend to prSe™ Syd?fuliS
thus rovidi
, en o pre™ yd
thus providing greater flexibility for water manLemen? a th
"
r
Pipelines carry an added maintenance responsibility for £
gators that is not required with concrete itches Y Many
were experienced with the roel
ree ces Many pro
were experienced with the propeller type flow meters that were
172
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used. Debris and sediment and pipe flow conditions have to be
exactly controlled, requiring a comprehensive maintenance program.
Field head ditches might be eliminated by conversion to
sprinkler or drip irrigation systems, but will be most likely
improved with either concrete linings or replaced by aluminum
qated pipe. Figures in Table 29 do not indicate a significant
difference in these two alternatives, although gated pipe is best
suited to diversion from piped laterals because of less head loss
in diverting the flow into the gated pipe, as well as fewer prob-
lems with debris. The costs per unit of salt reduction for head
ditch linings are two to three times higher than lateral linings
because of small average flows and more infrequent use. Automa-
tion is easily accomplished to improve the effectiveness of irri-
gations as illustrated by the cut-back system under Lateral MC 10
(Evans, 1977).
On-Farm Improvements
Nearly any field in the Grand Valley can be irrigated much
more efficiently if the amount of applied water during the first
two irrigations could be controlled. However, the added labor in
these two irrigations would be almost double that for the existing
practices (Skogerboe et al., 1974a). The soil infiltration rates
for subsequent irrigations are low enough that inefficiency is
difficult to achieve given the deeper rooting depths and higher
Et requirements, so little or no additional effort ^1*^ needed.
Unfortunately, irrigation scheduling experience locally indicates
that early season irrigations cannot be effectively controlled
simply by suggestion.
The options controlling the salinity generated by deep per-
colation include the following:
1) automation of existing furrow irrigation systems;
2) conversion to sprinkler or drip irrigation systems; and
3) field relief drainage.
Tailwater recycling is a measure to improve the efficiency of on-
farm water use, but would not significantly impact deep percola-
tion and salinity loading to the Colorado River.
Automation of head ditches or gated pipe is an alternative
with very strong qualifications in the Grand Valley. As noted
previously, the low soil infiltration rates maintain irrigation
Efficiency at a high level except during the early growing season.
Automation effectively replaces the added labor requirement during
this period, making substantial improvements feasible. Automation
also implies more rigid system design, which increases the ease
involved in applying irrigation scheduling recommendations.
173
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Replacing existing furrow or flood
either drip or sprinkler irrigation has
cavantaH
and tailwater ditches can be effectively elimnated whi?h*ef?e^
a significant salinity impact, and the soil no longer acts *«?**
controller since application rates are generally ?ower than th«
infiltration rates. Irrigators responded well to scheduling s
gestions and proved that water could be saved and
sions, but the effectiveness can also be substantial!
Field Drainage
Field drainage should primarily be installed for
,6 Cronl ;ir>r1e a o
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SECTION 10
LOCAL INSTITUTIONAL ASPECTS OF SALINITY CONTROL
PERMIT APPROACH
One of the objectives of this research project is to analyze
the effects of various "local" institutional influences upon
salinity control. The work under this objective was to include
an evaluation of the effects of tailwater runoff control, the
impact of a permit program, as well as evaluating the alterna-
tive of setting "influent" standards. Earlier experience with
the Grand Valley Salinity Control Demonstration Project had
indicated the necessary direction for a salinity control program,
which dictated to a large extent the experimental design for the
research and demonstration project discussed in this report. The
discussion that follows is an attempt to document in a simplistic
and not elaborate manner the necessary thrust for a salinity
control "permit" program in Grand Valley.
EPA Permit Program
The Federal Water Pollution Control Act Amendments of 1972
(PL 92-500) created a permit system for discharges from point
sources under Section 402 called the National Pollutant Discharge
Elimination System (NPDES). Through the permit program, point
source discharges are to be identified and their discharges moni-
tored to ensure that the effluent discharge limitations are main-
tained. The permit defines the obligations of the permittee in
complying with effluent limitations tailored to the specific
conditions of the permittee. Also, the permit sets out a compli-
ance schedule to be followed by the permit holder.
Because irrigated agriculture was not excluded under Section
301 of P.L. 92-500, it became subject to the permit program.
Between 1973 and 1975, regulations for a permit program pertain-
ing to irrigated agriculture were issued. There was considerable
backlash from irrigators and irrigation-oriented organizations
regarding the inappropriateness of such a permit program. More
recently, in 1976 and 1977, EPA has proposed a new General Permit
Program for irrigated agriculture.
The proposed new approach provides that water pollution from
most agricultural activities is considered nonpoint in nature
175
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and thus not subject to any permit requirements. However dis-
charges of pollutants into navigable waters through discrete
conveyences, which result from the controlled application of
water, are considered agricultural activity point sources.
Agricultural activities, particularly irrigation, which
result in surface discharges:
1) which contain pollutants;
2) which result from controlled application of water by
any person, and which are not caused or initiated sole-
ly by natural processes of precipitation;
3) which are discharged from a discernible, confined and
discrete conveyance; and
4) which are directly discharged into navigable waters;
are subject to regulation under Section 402, the NPDES permit
Clearly, this definition would apply primarily to irrigation
return flow ditches and drains. Although these ditches are con-
sidered point sources, in most cases there are no conventional
permit requirements at this time. Because of the lack of pollu-
tion control technology, discharges of agricultural wastes from
agricultural activity point sources are proposed to be permitted
by general permit (s). t^nnttea
On July 12, 1976, the EPA issued regulations which subjected
agricultural activities to general rather than individual water
pollution control permits. A point source is defined in the
agricultural category by these regulations as any discernible
confined and discrete conveyance from which any irrigation return
flow is discharged into navigable waters. Irrigation return flow
is defined as "surface water, other than navigable waters, con-
taining pollutants which result from the controlled application
of water by any person to land use primarily for crops, foraqe
growth, or nursery operations." These regulations recognized
that water pollution from most agricultural activities is con-
Subject to
The above discussion illustrates that the difficulties in
implementing a permit program for irrigation return flow quality
control have been more fully recognized in the last few years
The discussions that follow serve mostly as an argument for the
more recent action taken by EPA. This argument will be followed
by a discussion of the advantages of using influent standards
which could conceivably be included as an extension of the
presently proposed EPA General Permit Program.
176
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Nature of the Salinity Problem
Salinity problems from irrigated agriculture are the result
of subsurface return flows consisting primarily of: (a) seepage
losses from channels such as canals and laterals; and (b) deep
percolation losses from croplands. These sources of irrigation
return flow would be considered nonpoint; however, some portions
of these subsurface return flows could be intercepted by open or
tile drains or pumps which would then be considered point sources.
The NPDES permit program focuses upon the control of point
sources of pollution. The primary point sources of irrigation
return flow are canal bypass water, tailwater runoff, and collec-
ted drainage flows. These point sources are conveyed in channels
and could therefore be subjected to the provisions of a permit
program.
For the Grand Valley, the question becomes whether or not
the implementation of a permit program to control point sources
of irrigation return flow will have a significant impact upon
subsurface irrigation return flows, which are the cause of in-
creased salt loads reaching the Colorado River. In order to pro-
vide an answer to this question, as well as illustrate the magni-
tude of a permit program for Grand Valley, the following argument
discusses tailwater runoff and drainage return flow.
Tailwater Runoff and Drainage
The combination of heavy soils having low infiltration rates
and being "water rich" has resulted in a tremendous number of
tailwater runoff discharge points in Grand Valley. These dis-
charges are frequently reused by nearby farmers, dumped into
adiacent laterals or canals and conveyed to other farms, or dump-
ed into open drains or natural washes which convey return flow
to the Colorado River.
Examples from the lateral improvement program will
illustrate the number of tailwater runoff discharge points and
the utilization of these discharges. Before construction,
Lateral GV 95 and 6 points at which tailwater runoff was received
from other laterals (in 1976 this was close to 40 percent of the
total inflows to the lateral), 7 points at which tailwater was
received from other users on this lateral for reuse, and 18
points where tailwater runoff was discharged into open drains or
natural washes. After improvement, the number of discharge
points was reduced from 31 to 30 (Figure 61).
Another example is Lateral GV 160, where there are 4 dis-
charge points at which water is received from other laterals, 3
points at which water is returned to the lateral for internal
reuse, 4 points where runoff is discharged to other laterals or
canals and 15 points where tailwater runoff is discharged to
177
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a
O
Legend
Drainage Ditch
Road
Canal
Field Boundary
Inflow From Other Laterals
Internal Reuse
To Other Laterals Or Canals
To Drains Or Natural Washes
440 tea
Scel« in ftit
0 100 200 300
Mttert
Figure 61.
Colorado River
Identification of discharge points on Lateral
GV 95.
178
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drains or natural washes. There was no change in the number of
discharge points due to the construction of lateral improvements
on this lateral (Figure 62).
Before construction, for all of the nine laterals that were
included in this improvement program, there were 17 points at
which tailwater was received from other laterals, 21 points at
which tailwater was received from other users on the lateral for
internal reuse, 29 points 'at which tailwater runoff was discharg-
ed to other laterals or canals for reuse, and 60 points where
runoff was discharged to drains or natural washes. After con-
struction, there were still 17 points at which tailwater was
received, 21 points for internal reuse, 31 points of discharge to
other laterals on canals, and 58 points of discharge to drains or
washes leaving the total number of discharge points unchanged at
127. These results are for an irrigated area of 275 hectares
and 137 fields.
Taking into consideration the number of irrigated fields
(approximately 8,500) in Grand Valley, and the size distribution
of these fields, it is estimated that there are more than 15,000
individual discharge points within the irrigated area of the
Grand Valley. To control tailwater runoff by permitting individ-
ual farmers would require an estimated 15,000 permits for an
irrigated area of 29,000 hectares. In contrast, if each lateral
and drain were permitted, less than 1,600 permits would be re-
quired. The irrigation companies could assume the responsibility
for becoming the permittees, but at this time claim no responsi-
bility below the turnout gate which discharges water from the
company canal into the individual lateral.
The Grand Junction Drainage District has constructed 35 open
drains (which discharge directly to the river) throughout much
of the valley to convey irrigation wastewater. In addition,
there are nine major natural washes on the north side of the
valley which convey irrigation return flows and rainstorm runoff
to the Colorado River. No individual or organizational entity
will claim responsibility for these natural washes.
In the demonstration area, field measurements have shown
that approximately 22 percent of the flows in the drains and
washes consist of subsurface return flows intercepted by these
channels, while the major portion of the saline return flows
reaching the Colorado River are not conveyed by these drains and
washes. If it were possible to set effluent standards for tail-
water discharge, or the flows in drains and washes, such stand-
ards could only be partially successful in reducing the salt load
contribution from Grand Valley.
179
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Legend
Drainage Ditch
Road
Canal
Field Boundary
Inflow From Other Laterals
Internal Reuse
To Other Laterals Or Canals
To Drains Or To Lateral.
Natural Washes 6VI61
t
To Heodqate
a
o
Figure 62. Identification of discharge points for Lateral GV 160,
180
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Influent Standards
As stated earlier in this report, this research and demon-
stration project used each lateral as a subsystem because this
provided control at the lateral turnout gate. This turnout gate
is a critical control point in the irrigation system because it
represents the terminal point of responsibility for most of the
irrigation companies in Grand Valley (in some cases, under the
Grand Valley Water Users Association, there is responsibility
along the upper portions of the lateral). In turn, the control
point for each irrigation company is the point of diversion from
either the Colorado River or Gunnison River. The responsibility
for these river diversions belongs to a water commissioner who
is a state employee. The amount of water discharged at each
turnout gate is the responsibility of water masters or ditch
riders, who are employees of the particular irrigation company.
Generally, the water users under each lateral are not formal-
ly organized. However, in many cases, they have developed good
relations among themselves in developing a water rotation, or
each user gets the water on a continuous basis. There are also
many cases in which there is friction regarding the distribution
of the irrigation water supplies, which is aggravated by the lack
of flow measuring devices along the lateral for equitable dis-
tribution of the water supply. Compounding this situation further
are the numerous unmeasured tailwater runoff discharges which are
returned to the irrigation water supply or picked up by
neighboring farmers.
In the demonstration area, the lands under the Stub, High-
line, and Price Ditches have the water rights tied to the land
at 0.5 Colorado miners inch/acre continuous flow (38.4 Colorado
miners inches = 1.0 cfs or 1 Colorado miners inch = 0.74 1/s).
The water users served by the Grand Valley Canal and Mesa County
Ditch have shares (1 share =0.4 Colorado miners inch or 1 share
= 0.30 1/s) which can be traded, sold, rented or transferred
anywhere in the system.
The most common concept about water rights (or water duty)
in the project area is an old rule-of-thumb that 1 share per
acre (or the 0.4 to 0.5 Colorado miners inch) is adequate for
proper irrigation and almost every farmer was sure his diversions
were close to that amount. There are, however, only crude meas-
urements of the water diverted from the canals into the laterals
and, consequently, very little awareness as to the "actual" water
quantities used.
When numerous flow measurement devices were installed in
the project, most people found that they had been receiving 2 to
3 times their water allotment. After seeing their true rights,
most irrigators stated that . . ."I cannot irrigate with my
shares only". . . and immediately asked if they could get more
181
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water In order to facilitate these requests, allow rotation
flexibility, and meet peak water demands, the systems were over-
defigned based upon the water rights allocations. Proper
operation of the improved lateral subsystems will result in
significant diversion reduction as compared with diversions prior
to this construction program.
An initial influent standard goal should be the intended
water duty for the irrigated lands. This should be measured at
each farm inlet, which can then be translated back to the lateral
turnout gate taking into consideration lateral seepage losses
(which could be essentially ignored if the laterals were lined
or converted to pipelines). An important consideration should be
to use either a volumetric water duty as a standard, or a variable
flow rate which is dependent upon the changing water requirements
of the crops during an irrigation season.
The approach of using influent standards has the advantage
of alleviating the salinity problem by improved water management
practices, rather than end-of-pipe treatment, or partially reduc-
ing the salt load by using effluent standards under a permit
program. The success of an influent approach is dependent upon:
(a) use of numerous flow measuring devices; (b) adequate techni-
cal assistance for working with and advising farmers on improved
irrigation practices and methods; and (c) availability of funds
for making the necessary structural improvements. The fear of
loss of a water right, either by individual irrigators or the
irrigation companies, will likely be the greatest constraint in
implementing a valley-wide salinity control program.
TECHNOLOGY TRANSFER
Along with the research and demonstration programs, a major
objective of this project has been the development of vehicles
for transfer of technologies and technical packages to other
irrigated areas of the Upper Colorado River Basin and regions in
the western United States. Considerable experience has been
gained in working directly with farmers during the life of the
Grand Valley project. These experiences and farmer feedback dur-
ing the Irrigation Field Days plus research findings provide a
basis for the development of some broad guidelines for an exten-
sion program to facilitate the transfer of research findings to
other irrigated areas in Colorado and the West.
Given this purpose, the specific objectives of an extension
program are as follows:
1) encourage farmer participation;
2) train field personnel;
182
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3) organize water users;
4) develop basic farmer training materials;
5) recognize the efforts of farmers; and
6) evaluate extension activities.
This section of the report provides a brief discussion of
suggested means to attain these objectives. This includes meth-
ods to obtain farmer participation, the training of field-level
personnel, the development of basic training materials, and
methods for encouraging farmer organizations. The underlying
philosophy and assumptions of the discussion are: (a) that the
findings of the present research and improvement activities at
Grand Junction are applicable for other irrigated regions; and
(b) that a successful comprehensive salinity control program
requires active farmer participation.
Farmer Participation
One of the unique characteristics of improving on-farm
water management is that the degree of success is highly
dependent upon the degree of participation of each individual
farmer, as well as their ability to cooperate collectively for
the common good of all water users. The construction of on-farm
physical improvements only provides an increased potential for
water use efficiency, whereas the degree of potential that will
be achieved is dependent upon the operation and maintenance of
the physical improvements. This, in turn, is dependent upon the
level and ability of technical assistance provided, farmer atti-
tudes, and the degree of credibility between those individuals
providing the technical assistance and the farmers involved.
Credibility and acceptance by the farmers begins when the
basic training and motivational materials are initially used to
describe the problem. Efforts to organize the water users under
each lateral provide an opportune time to develop early rapport
with the farmers. Credibility and acceptance of the technical
personnel by farmers during the planning and implementation of
individual farm plans for improved water management is essential
to the long-range goals of a control program. Credibility and
good communication must exist during the collective negotiations
in determining the physical improvements to be made on a lateral,
Farmer participation is crucial during these stages in order to
evolve a plan of development which is acceptable to the water
users and also satisfies the goals of the salinity control
program.
The final step in this process dictates the real success of
the entire program. After spending vast sums of money to con-
struct physical improvements, the test of effectiveness revolves
183
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largely around the operation, management, and maintenance of
these improvements. This is the phase of the work where the
rapport developed with the farmers pays huge dividends. Unfortu-
nately, this step is very time-consuming and most frequently
neglected. Considerable evaluation is required to "tune-up"
these new improvements so that they are operating at their poten-
tial, and the key variable in this operation is the farmer
decision maker.
Tra in ing FieId Personnel
The primary agency providing technical assistance to farmers
for a salinity control program will likely be the Soil Conserva-
tion Service (SCS). The SCS will likely cooperate with the U.S.
Bureau of Reclamation (USER) in the provision of required tech-
nical assistance. Given the levels of manpower needed to work
with farmers, and the current shortage of trained manpower with
on-farm water management experience, special short courses for
training personnel will likely be required. As a complement to
technical competence, personnel^working directly with farmers
should know how to develop good working relationships with farmer
clients and have definite skills and knowledge related to organ-
izing farmers into water user associations for action programs.
Personnel also must have the capabilities required for assisting
farmers in "tuning-up" furrow irrigation practices and the main-
tenance of improved conveyance systems. Also, technical assis-
tance to farmers will include convincing them to use "scientific"
irrigation scheduling procedures and other improved irrigation
practices.
The focus on improved irrigation scheduling is essential
because the existing piece-meal methods of scheduling in Grand
Valley have been found to be inadequate as an individual salinity
control measure.
Water User Organizations
A crucial element in implementation of an effective salinity
control program is gaining the participation of the users. The
unit of organization should be the lateral system because it is
a natural hydrologic unit where farmers know each other and
interact on a day-to-day basis. In Grand Valley, the jurisdic-
tion of the irrigation companies does not include the laterals
in most cases; so, there is an organizational vacuum for most
laterals. The goal should be to gain participation by all water
users on each lateral. This may not always be possibly due to
human problems. While the organization could be on an ad hoc or
informal basis, experience indicates that it is probably best to
aim for a formal organization with rules developed by the members
themselves. A formal organization with its own rules and regu-
lations also makes it easier for the implementing agency because
all parties have a knowledge of the structure and mechanisms
184
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involved. When the leadership is defined, this facilitates the
work of the implementing agencies.
For example, the water users on several laterals in the
Grand Valley have organized formally as nonprofit mutual irri-
gation companies under the state laws of Colorado. One problem
the members of these associations have encountered has been law-
yer fees for incorporation. This can be partially overcome by
providing model sets of bylaws and other provisions to farmers
considering such organization. In fact, alternative models can
be provided farmers , and they should decide the set of rules and
regulations which meet their special needs for tne most effective
means of operation and maintenance of the lateral system. These
models could be provided in a well-prepared manual or booklet and
made available to interested farmers. The booklet should explain
the benefits of formal organization, how to organize_legally, and
the types of bylaws and provisions required. It is important
that such a booklet be well illustrated and in easily understood
language. Often such booklets are not well prepared and contain
too much legal jargon which farmers cannot fully understand. The
goal is to design usable materials on how-to-do-it for the farmer
audience.
Basic Farmer Training Materials
Materials are needed to motivate farmers and help them under-
stand the importance to themselves and their communities of im-
proving present water management practices for increased crop
production and the control of salinity.
Data obtained in problem identification and alternative solu-
tions to the problem should be utilized in preparing well-illus-
trated materials for farmers. These materials should graphically
and clearly define the problem, explain its consequences, docu-
ment the contributing factors, and explain the costs and benefits.
Alternative solutions should be carefully delineated and
estimated costs presented.
Techniques for such communications could include slide shows,
an easy-to-read booklet, and selected use of local mass media
channels. The slide show developed for the Grand Valley project
has been well received and has been presented many times in the
community at special public meetings and for civic groups. Also,
selected use of local mass media has been found to be useful.
Since a comprehensive salinity control program requires changes
in attitudes and behavior wherever such programs are proposed,
the first major consideration should be the design of definite
communication strategies. To make the program successful in
reaching all water users and the community, several complementary
communication methods should be used over time to reinforce the
central messages. Local conditions and communication sources
and channels need to be identified and used with imagination.
185
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Essentially, salinity control is a problem of water conservation
which requires much education on the part of farmers and
communities.
Farmer Client Recognition
The Irrigation Field Days held at Grand Valley, and other
experiences, have demonstrated the importance of farmer recog-
nition. Farmers usually can sell a program to other farmers more
successfully than public officials. Where possible, farmers
should be given special recognition, because the success of any
salinity control program rests finally with the degree of partic-
ipation by the farmers themselves. There are a number of methods
which can be effectively utilized for using farmer recognition to
motivate other farmers.
The proper use of radio and television announcements and
newspaper articles can be of considerable help in fostering en-
thusiasm for the program. The local newspaper provides excellent
coverage on news related to natural resources and agriculture.
Local newspapers in Grand Valley have beeir very helpful and always
willing to include news articles pertaining to the Grand Valley
Salinity Control Demonstration Project, The television station
and some radio stations in Grand Junction have cooperated with
the project in disseminating news related to the salinity control
research activities.
The news media, in addition to news reports about current
activities of the salinity program, are also very interested in
covering human interest stories. If these human interest reports
and farmers' testimonials are well prepared, they can create much
interest in other farmers for the programs. Such publicity is
free and probably can generate better image-building for state
and federal agencies than they can do for themselves.
Awards should be given to those farmers who have made excep-
tional progress in improving their on-farm water management prac-
tices. Awards for providing leadership in the water user associ-
ation under each lateral should be considered. Awards presented
to each water user served by the lateral demonstrating the most
efficient use of water would be highly effective in promoting
the goals of an improvement program. News media coverage of such
awards also provides additional incentives for improved water
management on the part of other farmers. Framed photographs of
farmers engaged in improvement activities with an inscription
could be considered for presentation. Plaques could be presented
to cooperators to show appreciation for their contributions.
An excellent method of using farmers for promoting wide
interest in a project once substantial progress has been made in
an improvement program is the use of field days. In the Grand
Valley, a Field Day could be held annually which would involve
186
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strong participation by local farmers. Water users and irrigation
company leadership from other valleys in the Upper Basin could be
given special invitations to attend the Field Days in order to
observe firsthand the implementation of a salinity control pro-
gram. In addition, special tours could be arranged during other
times of the year for a group of irrigators from any particular
area to visit the Grand Valley and meet with farmers who have
participated in the program. The emphasis should be farmer-to-
farmer interaction with the Grand Valley farmers being highlighted
rather than technical assistance personnel. These personnel,
however, should play a strong backstage role in facilitating this
interaction.
Evaluation of Extension Activities
It is not sufficient to randomly develop extension and pro-
motional activities for the transfer of technologies for salinity
control improvement programs. Technical personnel in such proj-
ects should be given short courses in skills needed for working
effectively with farmers. Extension communication strategies
should be designed into the project proposal and work plans in
order that various techniques can be effectively evaluated.
While technical expertise for such programs is usually adequate,
there is a general weakness in designing and evaluating extension
communication strategies. As stated often in this report, the
key variable in achieving successful program implementation and
long-term effective maintenance of improved systems is the farmer
client himself. Since this is the case, professional assistance
is required from extension or communication personnel to assure
that sufficient attention is given to these important areas.
It is, therefore, recommended that communication techniques
used for working with farmers as individuals and groups be design-
ed into programs and evaluated to the same degree as the techni-
cal components and activities. Evaluative research techniques
are available which, if properly utilized, can be used to deter-
mine the strengths and weaknesses of project implementation.
Information from such evaluative studies is needed by sponsoring
agencies and by project implementors to discover the most effec-
tive and efficient methods of working cooperatively with farmers.
187
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REFERENCES
-r T? 1942 Irriqation by Sprinkling, California
r Station Bu!le?in No. 570.
^ Aaricultural Experiment Station, 1955. Irrigation Water
COl0rApplication and Drainage of Irrigated Land in the Upper
Colorado River Basin, Progress Report 1954. Project W-28,
Department of Civil Engineering, Colorado A & M College,
Fort Collins, Colorado. March. 38 p.
„ p EG Kruse, S. R. Olsen, D. F. Champion, and D. C.
°U 'Kincaid, 1976. Irrigation Return Flow Quality as Affected
bv Irrigation Water Management in the Grand Valley of Colo
rado Agricultural Research Service, U. S. Department of
Agriculture, Fort Collins, Colorado. October.
r, «a Robert G. , 1977. Improved Semi-Automat ic Gates for Cut-
EV Back Iurfac4 Irrigation Systems. Transactions of the ASAE,
Vol. 20, No. 1. PP 105-108, 112.
rt W E. , 1961. Overhead Irrigation Pattern Parameters. Agn-
'cultural Engineering. July. p. 354-355.
li D., 1977. Water Distribution Patterns for Sprinkler and
Surface Irrigation Systems. Proceedings of the National
Conference on Irrigation Return Flow Quality Management,
Fort Collins, Colorado. May 16-19. p. 233-251.
4-hPrs K C , 1975. The Economics of Managing Saline Irriga-
tion Return Flows in the Upper Colorado River Basin: A Case
Study of Grand Valley, Colorado. PhD Dis. , Department °=
Economics, Colorado State University, Fort Collins, Colorado
rboe G. V. and W. R. Walker, 1972. Evaluation of Canal
Inq for Salinity Control in Grand Valley. Report EPA-R2-72-
047 Office of Research and Monitoring, Environmental Pro
tection Agency, Washington, D. C. October. 199 p.
01 ^rhoe G. V., W. R. Walker, J. H. Taylor, and R. S. Bennett,
Skogercoe, luation of Irrigation Scheduling for Salinity
rontrol in Grand Valley. Report EPA-660/2-74-052, Office of
Research and Development, Environmental Protection Agency/
Washington, D. C. June. 86 p.
188
-------
Skogerboe, G. V., W. R. Walker, R. S. Bennett, J. E. Ayars, and
J. H. Taylor, 1974b. Evaluation of Drainage for Salinity
Control in Grand Valley. Report EPA-660/2-74-084, Office of
Research and Development, Environmental Protection Agency,
Washington, D. C. August. 100 p.
U. S. Department of Agriculture, Soil Conservation Service, 1976.
Inventory of Conservation Plan Needs for the Grand Valley.
Open Pile Data, Grand Junction, Colorado.
U. S. Department of Agriculture, Soil Conservation Service and
Colorado Agricultural Experiment Station, 1955. Soil Survey,
Grand Junction Area, Colorado. Series 1940, No. 19. November,
118 p.
U. S. Department of Commerce, Environmental Science Services
Administration, Environmental Data Service, 1968. Local
Climatological Data, Grand Junction, Colorado.
U. S. Department of Commerce, Environmental Science Services
Administration, Environmental Data Service, 1972. 1969 Cen-
sus of Agriculture, Volume 1 — Area Reports, Part 41 —
Colorado. May.
U. S. Environmental Protection Agency, 1971. The Mineral Quality
Problem in the Colorado River Basin. Summary Report and
Appendices A, B, C, and D. Region 8, Denver, Colorado.
Walker, W. R., 1975. A Systematic Procedure for Taxing Agricul-
tural Pollution Sources. Grant NK-42122, Civil and Environ-
mental Technology Program, National Science Foundation,
Washington, D. C. October.
Walker, W. R., 1977. Integrating Desalination and Agricultural
Salinity Control Strategies, (report in press) Office of
Research and Development, Robert S. Kerr Environmental
Research Laboratory, U. S. Environmental Protection Agency,
Ada, Oklahoma.
Walker, W. R. and G. V. Skogerboe, 1971. Agricultural Land Use
in the Grand Valley. Agricultural Engineering Department,
Colorado state University, Fort Collins, Colorado.
Walker, W. R., 1970. Hydro-Salinity Model of the Grand Valley.
MS Thesis , No. CET-71-WRW8. Civil Engineering Department
College of Engineering, Colorado State University,' Fort
Collins, Colorado. August.
Young, R. A., G. E. Radosevich, S. L. Gray, and K, L. Leathers,
1975. Economic and Institutional Analysis of Colorado Water
Quality Management. Completion Report Series No. 61.
Environmental Resources Center, Colorado state University
Fort Collins, Colorado. March. '
189
-------
BIBLIOGRAPHY
Beckwith, E. G., 1854. Report of Explorations for a Route for the
Pacific Railroad: U. S. Pacific R. R. Explo. V. 2, 128 p.
Colorado Agricultural Experiment Station, 1955. Irrigation Water
Application and Drainage of Irrigated Lands in the Upper
Colorado River Basin. Contributing Project Progress Report,
Western Regional Research Project W-28. November. 37 p.
Colorado River Board of California, 1970. Need for Controlling
Salinity of the Colorado River. The Resources Agency, State
of California. August. 89 p.
Colorado Water Conservation Board and U. S. Department of Agri-
culture, 1965. Water and Related Land Resources Colorado
River Basin in Colorado. Denver, Colorado. May. 183 p.
Decker, R. S., 1951. Progress Report on Drainage Project (1945
to January, 1951). Grand Junction, Colorado, Lower Grand
Valley Soil Conservation District, Mesa County, Colorado.
January. 37 p.
Elkin, A. D., 1976. Grand Valley Salinity Study: Investigations
of Sediment and Salt Yields in Diffuse Areas, Mesa County,
Colorado. Review Draft Submitted for the State Conservation
Engineer, Soil Conservation Service, U. S. Department of
Agriculture, Denver, Colorado.
Fremont, J. C., 1845. Report of the Exploring Expedition to the
Rocky Mountains in the Year 1842 and to Oregon and North
California in the Years 1843-44: Washington, Gales and
Seaton, U. S. Senate. 693 p.
Grand Junction Chamber of Commerce, 1975. Grand Junction, Colo-
rado - An Economic Overview, 1975-76.
Hagan, Robert M., Howard R. Haise, and Talcott W. Edminster,
Editors, 1967. Irrigation of Agricultural Lands. No. 11 in
the series, Agronomy. American Society of Agronomy, Madison,
Wisconsin. 1180 p.
Hafen, L. R., 1927. Coming of the White Men: Exploration and
Acquisition. In: History of Colorado, Denver Linderman Co.,
Inc., State Hist. Nat. History Soc. Colorado. Vol. 1. 428 p.
190
-------
Hayden, V. F., 1877. Report of Progress for the Year 1875: U. S.
Geol. and Geog. Survey Terr. Embracing Colorado and Parts
of Adjacent Territories. 827 p.
Hyatt, M. Leon, 1970. Analog Computer Model of the Hydrologic and
Salinity Flow of Systems within the Upper Colorado River
Basin. PhD Dissertation, Department of Civil Engineering,
College of Engineering, Utah State University, Logan, Utah.
July.
Hyatt, M. L., J. P. Riley, M. L. McKee, and E. K. Israelsen, 1970,
Computer Simulation of the Hydrologic Salinity Flow System
Within the Upper Colorado River Basin. Utah Water Research
Laboratory, Report PRWG54-1, Utah State University, Logan,
Utah. July.
Iorns> W. V., C. H. Hembree, and G, L. Oakland, 1965. Water
Resources of the Upper Colorado River Basin. Geological
Survey Professional Paper 441, U. S. Government Printing
Office, Washington, D. C.
Jensen, M. E., 1975. Scientific Irrigation Scheduling for Salin-
ity Control of irrigation Return Flow. EPA-600/2-74-064.
Robert S. Kerr Environmental Research Laboratory, Office of
Research and Development, Environmental Protection Agency,
Washington, D. C. August.
Leathers, K. L. and R. A. Young, 1975. The Economics of Managing
Saline Irrigation Return Flows in the Upper Colorado River
Basin: A Case Study of Grand Valley, Colorado. Report for
Project 68-01-2660, Region 8, Environmental Protection
Agency, Denver, Colorado. June.
Lohman, S. W., 1965. Geology and Artesian Water Supply, Grand
Junction Area, Colorado. Geological Survey Professional
Paper 451. U. S. Government Printing Office, Washington,
D. C. 149 p.
Miller D. G., 1916. The Seepage and Alkali Problems in the Grand
Valley, Colorado. Office of Public Roads and Rural Engin-
eering, Drainage Investigations. March 43 p.
Sternberg, G. V. The Grand Valley Canal and Water Rights.
U. S. Department of Agriculture and Colorado Agricultural Exper-
iment Station, 1957. Annual Research Report, Soil, Water,
and Crop Management Studies in the Upper Colorado River
Basin. Colorado State University, Fort Collins, Colorado.
March. 80 p.
191
-------
U. S. Department of Agriculture, U. S. Salinity Laboratory, 1954.
Diagnosis and Improvement of Saline and Alkali Soils. Agri-
cultural Handbook No. 60. February.
U. S. Department of Interior, Bureau of Reclamation, 1968. Use of
Water on Federal Irrigation Projects, Final Report 1965-1968.
Volume 1, Summary and Efficiencies. Grand Valley Project,
Colorado. Region 4, Salt Lake City, Utah.
U. S. Geological Survey, 1976. Salt-Load Computations — Colorado
River: Cameo, Colorado to Cisco, Utah. Parts 1 and 2. Open
File Report. Denver, Colorado.
Valantine, V. E., 1974. Impacts of Colorado River Salinity. Jour-
nal of the Irrigation and Drainage Division, Amer. Soc Civil
Engrs., Vol. 100, No. IR4, p. 495-510. December.
Water Resources Council, 1972. OBERS Projections, Regional Eco-
nomic Activity in the U. S.; Volume 4. Washington, D. C.
Westesen, G. L., 1975. Salinity Control for Western Colorado
Unpublished PhD Dissertation. Colorado State University*
Fort Collins, Colorado. February. '
192
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1. REPORT NO.
EPA-600/2-78-160
4. TITLE AND SUBTITLE
IMPLEMENTATION OF AGRICULTURAL SALINITY CONTROL
TECHNOLOGY IN GRAND VALLEY
6. PERFORMING ORGANIZATION CODE
7. AUTHOH(S)
R. G. Evans, W. R. Walker, G. V. Skogerboe, and
E. U
8. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Colorado State University, Department of Agricultural
and Chemical Engineering, Fort Collins, Colorado
80523
—
12. SPONSORING AGENCY NAME AND ADDRESS U/iv^fr.™ flHa ("Ik
Robert S. Kerr Environmental Research Laboratory-Ada,OK
Office of Research and Development
U.S. Environmental Protection Agency
Ada, Oklahoma 74820
5. REPORT DATE
July 1978 issuing date
10. PROGRAM ELEMENT NO.
1BB770
Tl. CONTRACT/GRANT NO.
S-802985
Final
14. SPONSORING AGENCY CODE
EPA/600/15
15. SUPPLEMENTARY NOTES
192 pages. 62 fig. 29 tab. 46 ref.
16. ABSTRACT
A summary of the results
flows in the Grand Valley 'I^'^"^^^"^ Grand Valley Salinity Control
Salinity and economic impacts are ae5^ , tely T 600 hectares and involves most
Demonstration Project which contains approx mately , ^ of ^
of the local irrigation companies in tne ^^j^ 26*54 km of laterals were lined,
demonstration project, 12.2 km or can^+.all , n-de variety of on-farm improvements
, ,eu, _ ^ _^ On_farm
e
16, 400 meters of dra1nage_ tile were inswH , program was implemented.
were constructed, and an irrigation scheduling^ ^_nU sprinklers, drip (trickle)
^! ^ cut-back furrow irrigation. The total
™a
demonstration area was about $750,000.
improvements evaluated were
irrigation, furrow irrigation, and
value of the constructed imP^e^ sait,eduction of 12,300 metric tons per year
The total improvements resulted in a salt r ^^^ .^ ^ annua1 benefn to
reaching the Colorado River. This san. r ^ addition} there are benefits to the
downstream water users of nearly VW'J ^ and to tne people Of Grand Valley in
local water users with increased
increased business.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Irrigation? Di'tches ee-
Salinity, Saline soils, Salt water, See
page, Water distribution
13. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
b.IDENTIFIERS/OPEN ENDED TERMS
"•Irrigation (management,
practices, effects, water,
efficiency, systems),
Grand Valley, Colorado
River, Salinity control,
*Return flow, Infiltra-
tion rates
19. SECURITY CLASS (This Report)
UNCLASSIFIED'-
20. SECURITY CLASS (This page)
UNCLASSIFIED
EPA Form 2220-1 (9-73)
* U. S. 60VE.MMENT PRINTING OFFICE: ,978-757-140/1411 Region No. Ml
rsr
c. COSATl Field/Group
98C
21. NO. OF PAGES
209
22. PRICE
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