Guidelines for designing and evaluating
surface irrigation systems
Table of Contents
FAO IRRIGATION AND DRAINAGE PAPER 45
by W.R. Walker
Professor and Head
Department of Agricultural and Irrigation Engineering
Utah State University
Logan, Utah, USA
(Consultant to FAO)
FAO
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
Rome, 1989
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M-56
ISBN 92-5-102879-6
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Preface
Acknowledgements
1.
The practice of irrigation
1.1
The perspective and objectives of irrigation
1.2
Irrigation methods and their selection
1.2.1
Compatibility
1.2.2 Economics
1.2.3
Topographical characteristics
1.2.4 Soils
1.2.5 Water
supply
1.2.6 Crops
1.2.7
Social influences
1.2.8
External influences
1.2.9 Summary
1.3
Advantages and disadvantages of surface irrigation
1.3.1 Advantages
1.3.2
Disadvantages
2.
Surface irrigation systems
2.1
Introduction to surface irrigation
2.1.1 Definition
2.1.2
Scope of the guide
2.1.3
Evolution of the practice
2.2
Surface irrigation methods
2.2.1 Basin
irrigation
2.2.2
Border irrigation
2.2.3
Furrow irrigation
2.2.4
Uncontrolled flooding
2.3
Requirements for optimal performance
2.3.1
Inlet discharge control
2.3.2
Wastewater recovery and reuse
2.4
Surface irrigation structures
2.4.1
Diversion structures
2.4.2
Conveyance, distribution and management structures
2.4.3
Field distribution systems
3. Field
measurements
3.1
Field topography and configuration
3.2
Determining water requirements
3.2.1
Evapotranspiration and drainage requirements
3.2.2
Soil moisture principles
3.2.3
Soil moisture measurements
3.2.4
An example problem on soil moisture
3.3 Infiltration
3.3.1
Infiltration functions
3.3.2
Typical infiltration relationships
3.3.3
Measuring infiltration
3.3.4
An example infiltrometer test
3.4 Flow
measurement
3.4.1
Cutthroat flumes
3.4.2
Example of cutthroat flume calibration
3.4.3
Rectangular thin-plate weirs
3.4.4
Example of rectangular sharp crested weir analysis
3.4.5 V-notch
weirs
3.5 Field
evaluation
3.5.1 Advance
phase
3.5.2
Ponding phase or wetting
3.5.3
Depletion phase
3.5.4
Recession phase
4.
Evaluation of field data
4.1
Objectives of evaluation
4.1.1 Field data
4.2
Performance measures
4.2.1
Application uniformity
4.2.2
Application efficiency
4.2.3
Water requirement efficiency
4.2.4
Deep percolation ratio
4.2.5
Tailwater ratio
4.2.6
Integration measures of performance
4.3
Intermediate analysis of field data
4.3.1
Inflow-outflow
4.3.2
Advance and recession
4.3.3 Flow
geometry
4.3.4
Field infiltration
4.4 System
evaluation
4.4.1
Furrow irrigation evaluation procedure
4.4.2
Border irrigation evaluation
4.4.3
Basin irrigation evaluation
4.5
General alternatives for improvement
4.6
An example furrow irrigation evaluation
4.6.1
Field infiltration characteristics
4.6.2
Evaluation of system performance
4.6.3
Measures to improve performance
5.
Surface irrigation design
5.1
Objective and scope of design
5.2
The basic design process
5.2.1
Preliminary design
5.2.2
Detailed design
5.3
Computation of advance and intake opportunity time
5.3.1
Common design computations
5.4
Furrow irrigation flow rates, cutoff times, and field layouts
5.4.1
Furrow design procedure for systems without cutback or reuse
5.4.2
Design procedure for furrow cutback systems
5.4.3
Design of furrow systems with tailwater reuse
5.4.4
Furrow irrigation design examples
5.5
Border irrigation design
5.5.1
Design of open-end border systems
5.5.2
Design of blocked-end borders
5.5.3
An open-end border design example
5.5.4
A blocked-end border design example
5.6 Basin
irrigation design
5.6.1
An example of basin design
5.7 Summary
6. Land
levelling
6.1
The importance of land preparations
6.2
Small-scale land levelling
6.3
Traditional engineering approach
6.3.1
Initial considerations
6.3.2
Engineering phase
6.3.3
Adjusting for the cut/fill ratio
6.3.4
Some practical problems
6.3.5 An
example problem
6.4 Laser
land levelling
7. Future
developments
7.1 Background
7.2 Surge flow
7.2.1
Effects of surging on infiltration
7.2.2
Effects of surging on surface flow hydraulics
7.2.3
Surge flow systems
7.3 Cablegation
7.4
Adaptive control systems
7.5
Water supply management
References
Appendix
I - Fortran 77 surface irrigation design program
FAO
irrigation and drainage papers
http://www.fao.org/docrep/T0231E/T0231E00.htm |