625578014
IRRIGATED
AGRICULTURE
AND
WATER QUALITY
MANAGEMENT
AOGNCY
DALLAS. TEXAS
UHIW
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EPA-625/5-78-014
April 1978
Introduction
The EPA Irrigated Crop Production Research
Program, located at the Robert S. Kerr
Environmental Research Laboratory in Ada,
Oklahoma, has made substantial progress in the
past five or six years. Numerous research
projects and investigations have been recently
completed (or are nearing completion) which
focused upon defining appropriate technologies
for alleviating water quality problems from
irrigated agriculture; most of these technologies
involve improved water management practices. In
addition, case studies have provided necessary
experiences as to how such technologies might
be implemented. These field experiences,
combined with studies of legal approaches, as
well as studies concerned with defining the
processes of implementation and the socio-
economic considerations that must be taken into
account prior to and during implementation, have
provided valuable insights as to the available
alternatives for implementing programs of
irrigation return flow quality management.
We are now at that point in time where sufficient
research and investigation has been completed
so that more intelligent decisions can be made to
solve the water quality problems of irrigated
agriculture. These problems need to be
addressed. From a national and local standpoint,
now is the time for everyone concerned to
provide their inputto weigh the alternatives and
voice their opinionsin order that appropriate
and viable programs will be implemented that are
sensitive to both local and national needs and
priorities.
Dr. James P. Law Jr.
Robert S Kerr, Environmental
Research Laboratory
Ada, Oklahoma
Dr. Gaylord V. Skogerboe
Colorado State University
Ft. Collins, Colorado
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The Problem
All of man's water consumption activities
result in pollution
Irrigation Pollutes
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And, irrigation is the largest water
consuming activity in the West.
Irrigated agriculture contributes sediment,
salts, fertilizers and pesticides (biocides) to
ground and surface waters.
Irrigated Agriculture contributes
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These pollutants result in damages to other
irrigated areas, to wildlife habitats, cities and
industries.
These pollution problems cross both state
and international boundaries and affect our
relations with neighboring states, the
Republic of Mexico and Canada.
nmnfataim h ^uod* M m mifr' **"'-
piwMRM fWHin irom poiiumn.
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If we want to reduce pollution from irrigated
agriculture
Or increase agricultural production on
existing croplands
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Or reduce water diversions to irrigated
agriculture so that new water demands can
be met.
The solutions are identical!!
Improved Water Management Practices
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But,
the solutions are "site specific" in that each
geographical irrigated area is different.
Also,
some irrigated areas contribute
significantly to pollution
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And,
some irrigated areas contribute relatively
insignificant amounts of pollutants.
So, for each geographical irrigated area, the
following questions must be asked.
How significant is the resulting
pollution?
If the pollution is significant, what are
the appropriate remedies that suit the
"site specific" nature of the particular
irrigated area?
What is the effect of demonstrating
these remedies on farmers' fields?
What mechanisms must be developed
for meeting the costs associated with
implementing the various remedies?
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The Irrigation System
An irrigation system is broken down into 4
subsystems
1. Water Source
2. Water Delivery
3. On-Farm Water Use
4. Water Removal
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Water Quality Problems
IRRIGATED AGRICULTURE
WATER MANAGEMENT PRACTICES AGRICULTURAL PRACTICES
Degraded Irrigation Return Flows
THE IMPACT
Deterioration of Ground Water and Surface Water Quality
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POLLUTION FROM SURFACE
RUNOFF
Water Source:
Tailwater Runoff from Croplands
Pollutants Transported during Delivery, Use
and Removal of Water:
Sediments
Phosphates from fertilizer
Crop Residue
Biocides: toxic substances from
pesticides and herbicides
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POLLUTION FROM SUBSURFACE
FLOWS
Water Sources:
Seepage Losses from Canals and
Laterals
Deep Percolation Losses from
Croplands
BOTTOM or
"HOOT ZONE
Pollutants Transported during Delivery, Use
and Removal of Water:
Mineral Salts
Nitrates from fertilizer
And other water soluble constituents
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Solutions for
Surface Runoff Pollution
You can treat the problem
Tailwater Reuse System
Vegetative Strips
Sediment Collection Basins
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OR, you can treat the source
Contour Farming
Land Leveling
Cut-Back Furrow Irrigation
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Sprinkler Irrigation
Trickle Irrigation
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Solutions For
Subsurface Flow Pollution
Seepage losses can be reduced by
Lining Channels with Concrete, Gunnite,
Asphalt-membrane, Plastic-membrane, etc.
Or, replace earth ditches with Pipelines
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Some deep percolation is necessary to
remove the salts from the root zone so that
the cropland remains productive.
But, much can be done to reduce deep
percolation losses, increase water use
efficiency, and assure more uniform water
distribution across the field.
Better furrow flow control
Cut-back furrow irrigation
"Tune Up" the existing surface irrigation
systems by improving present management
practices.
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Use pressurized irrigation methods to
provide better water control (including
automation) so that the proper quantities of
water are applied uniformly over a field.
Sprinkler Irrigation
Trickle Irrigation
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Employ Flow Measuring Devices throughout
the irrigation system in order to distribute
the water to each farmer and at each farm
inlet equitably so the farmer knows "what he
is managing and how much he is applying."
Use "Scientific Irrigation Scheduling" so that
each farmer receives the proper amount of
water at the right time to insure good crop
growth.
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Importance of
On-Farm Water Management
Usually, the key to reducing problems of
water pollution resulting from irrigated
agriculture is improved on-farm water
management practices.
MAN is the key to MANagement
Improved Water MANagement requires more
and better management practices by MAN in
the use of his water.
The construction of physical improvements
increases the potential for improved water
management, but it is the operation and
management of these improvements that
dictates how much of this potential is
achieved.
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Implementation
Legal Problems
The major impediment to improved water
management practices is the irrigator's fear
of losing his water rights.
Major cause of the pollution problem is the
use of too much water.
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The major constraint to change is our
system of water rights.
The Doctrine of Prior Appropriation has
irrigators diverting their "full" water right for
fear of losing their right.
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The primary legal elements which contribute
to the problem are:
Failure to enforce existing beneficial
use and nonwaste provisions in State
water laws.
Prevention of the transfer of excess and
saved water to other lands or users.
Separate categories of law exist for
water quantity and for water quality.
Lack of funds, or restrictions, for
improving irrigation systems to alleviate
water quality degradation.
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Economic Problems
Water is allocated on a priority of rights
rather than on the value of use
And
The price of water is generally the
conveyance cost to the farm,
which results in
Water use not being competitive nor
responsive to the market place (e.g.,
new demands)
Water that is not allocated to its highest
valued use
Excessive water application because of
low price.
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Social Goals
A positive incentive should be provided for
irrigators to benefit from improving their
water management practices by establishing
a market for selling, renting and leasing
water.
The transfer of saved water to new uses
should have safeguards to protect water
quality.
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Appropriate solutions must be developed
with a sensitivity to local conditions.
Since irrigation is a collective enterprise,
existing irrigation districts should play a
major role in implementing solutions.
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State-wide and regional advisory committees
should play a role in establishing
coordination and cooperation among water
users.
Credibility and trustworthiness of federal
and state agencies in the eyes of irrigators
should be established to provide the
important final ingredient.
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Influent Control Approach
A SOLUTION:
An Influent Control Approach (ICA)
ASSUMPTION:
Improved Agricultural Practices + Improved Water Management =
Improved Water Quality (IAP + IWM = IWQ)
CONCLUSION
Best Management Practices + Best Agricultural Practices =
Irrigation Return Flow Quality Control (BMP + BAP = IRFQC -»IWQ)
DEFINITIONS:
BMP - Improved Local Water Management (ILWM)
BAP = Proper Land Use (PLU) and Proper Application of Agricultural Chemicals (PAAC)
INFLUENT CONTROL APPROACH (ICA)
^* ACTION
BEST MANAGEMENT
PRACTICES (BMP)
BEST AGRICULTURAL
PRACTICES (BAP)
Improved Local Water
Management (ILWM)
Proper Land Proper Application of
Use (PLU) Agricultural Chemicals (PAAC)
COMPONENTS
3 Introduce in-
centives for
ILWM
4 Add water
quality to water
rights
6 Recognize rea-
sonable degra-
7 Adopt Agncul-
cals fertilizers
and biocides
V
i Promote close cooperation or integration of state w
agencies and other related functions
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National Goals
Implementing a cost-effective program for
improving present irrigation management
practices will play an important role in the
West to
.have Cleaner Water
.increase Crop Production
.meet New Water Demands
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References
The following reports have resulted from
EPA's Irrigated Crop Production Research
Program
Report No
EPA-eoo/2- Assessment of Irrigation Return Flow Models
76-219 BY: W. R. Walker, Colorado State University,
Fort Collins, CO
ORDER FROM:- GPO
NTIS-PB 263 897/AS
(83 pages)
EPA-eoo/2- Control of Sediments, Nutrients, and Adsorbed
76-237 Biocides in Surface Irrigation Return Flows
BY: D. L. Carter and J A. Bondurant, U.S.
Department of Agriculture, Snake River
Conservation Research Center, Kimberly,
Idaho
ORDER FROM: GPO
NTIS-PB 263 610/AS
(53 pages)
EPA-eoo/2- Effects of Irrigation Methods on Groundwater
76-291 Pollution by Nitrates and Other Solutes
BY: C. W. Wendt, A. B. Onken, and O. C.
Wilke, Texas Agricultural Experiment
Station, Lubbock; R. D Lacewell, Texas
A & M University, College Station, TX
ORDER FROM. GPO
NTIS-PB
(359 pages)
EPA-eoo/2- Irrigation Management Affecting Quality
76-226 and Quantity of Return Flow
BY: L. S. Willardson and R. J. Hanks, Utah
State University, Logan, UT
ORDER FROM: GPO
NTIS-PB
(206 pages)
EPA-eoo/2- Nitrogen and Irrigation Management to Reduce
76-158 Return-Flow Pollution in the Columbia Basin
BY: B. L. McNeal and B. L. Carlile, Washington
State University, Pullman, WA
ORDER FROM- GPO
NTIS-PB 259 328/AS
(141 pages)
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EPA-eoo/2- Scientific Irrigation Scheduling for Salinity
Control of Irrigation Return Flows
BY: M. E. Jensen, U.S. Department of Agri-
culture, Kimberly, ID
ORDER FROM. GPO
NTIS-PB 2491 WAS
(91 pages)
EPA-R2- Prediction Modeling for Salinity Control in
73-168 Irrigation Return Flows
BY: A. G. Hornsby, Robert S. Kerr Environ-
mental Research Laboratory, USEPA,
Ada, OK
ORDER FROM: GPO-EP 1.23/2:R2-73-168
NTIS-PB 221 647
(55 pages)
Selected Irrigation Return Flow Quality
Literature Abstracts
BY: G. V. Skogerboe, et al., Colorado State
University, Fort Collins, CO
1968-1969. NTIS-PB 214 105
1970-1971. NTIS-PB 222 796
1972-1973. NTIS-PB 235 385
1974. NTIS-PB 253 664/AS
1975. RSKERL
1976
* Evaluation of Measures for Controlling
Sediment and Nutrient Losses from Irrigated
Areas
BY D. W. Fitzsimmons, et al., University of
Idaho, Moscow, ID R-803524
* Best Management Practices for Salinity Control
in Grand Valley
BY: W. R. Walker, G. V. Skogerboe and
R. G. Evans, Colorado State University,
Fort Collins, CO
Implementation of Agricultural Salinity Control
Technology in Grand Valley
BY: R. G. Evans, W. R. Walker, G. V. Skogerboe
and C. W. Binder, Colorado State
University, Fort Collins, CO
Western Water Laws and Irrigation Return Flow
BY: G. E. Radosevich, Resources Adm. and
Dev., Inc., Fort Collins, CO
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" Achieving Irrigation Return Flow Quality Control
Through Improved Legal Systems
BY- G. E. Radosevich and G V Skogerboe,
Resources Adm. and Dev., Inc., Fort
. - Collins, CO
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Socio-Economic and Institutional Factors in
Irrigation Return Flow Quality Control
BY E C. Vlachos, P. C Huszar, G. E.
Radosevich, G. V. Skogerboe and W. L.
Trock, Colorado State University, Fort
Collins, CO
Volume I: Methodology
Volume II: Yakima Valley
Volume III Middle Rio Grande
Volume IV: Grand Valley
* Integrating Desalination and Agricultural
Salinity Control Alternatives
BY Wynn R Walker, Colorado State University,
Fort Collins, CO
Assessing the Spatial Variability of Irrigation
Water Applications
BY D Karmeli, W. R. Walker and L. J. Salazar,
Colorado State University, Fort Collins, CO
If no GPO or NTIS numbers are shown for report, the
report-may be ordered by EPA number and title from
the appropriate source An asterisk by report indicates
report has been forwarded for printing and will be
available by Fall, 1978 from RSKERL
For additional information contact:
Dr James P Law Jr, Chief,
Irrigated Agriculture Section
Robert S Kerr, Environmental Research Lab
PO Box 1198
Ada, Oklahoma 74820
Additional copies of this brochure may be secured
by writing
U S EPA ERIC
Cincinnati, Ohio 45268
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