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ARS Home » Research » Publications at this Location » Publication #74959
Title: BORDER -- A DESIGN AND MANAGEMENT AID FOR SLOPING BORDER IRRIGATION SYSTEMS

Author
item STRELKOFF, THEODOR - UNIVERSITY OF AZ, TUCSON
item Clemmens, Albert
item SCHMIDT, BARON - UNIVERSITY OF AZ, TUCSON
item SLOSKY, EDWARD - ?

Submitted to: Model and Computer Program Software Documentation
Publication Type: Government Publication
Publication Acceptance Date: 6/1/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Surface irrigation generally suffers a poor reputation for water conservation and for transport into the environment of agricultural chemicals and sediment through excessive discharges from the irrigated fields. This, in part, has provided motivation for expensive conversions to pressurized systems. Still, in the U.S., about half of the irrigated lands are watered by surface methods; in some parts of the world, this figure approaches 100%. Fortunately, with modern techniques of design and operation, much can often be done to improve the performance of surface systems. In laser-levelled basins, efficiencies have been achieved on a par with well designed and operated pressurized systems. Software to aid in the design and management of such basins has been in existence for several years. For irrigation of sloping strips of land between borders, however, much design is still based on empirical observations of less than universal application, quasi-theoretical analyses, and/or designer experience and artistry. Now, newly created software can guide the development of proper design and operation. Based on universal physical laws governing water flow, and subject to best estimates of field infiltration and roughness conditions, the program provides screens full of curves describing the influence of physical design and management parameters on system performance. These curves show what performance levels are possible under the given field conditions, and what values design parameters should have to achieve those levels. The software is intended for farm advisors, extension agents, mobile irrigation- evaluation labs, NRCS field personnel, consultants, and others in a position to advise irrigators.

Technical Abstract: Improving the design and operation of sloping border-strip irrigation systems is the intent of the new software program "BORDER." A dimensionless database of previously executed simulations of sloping- border irrigation with tailwater runoff constitutes the heart of this user-friendly design-aid software. It can show the effects on user-selected performance indicators of variations in design and managemen variables. The physical design variables are border-strip length and unit inflow rate. Unit inflow rate determines border-strip width if total stream capacity is known, or total flow rate to the border-strip if width is given. At each unit flow rate and border-strip length viewed, the cutoff time (or stream advance at cutoff) is automatically found by interpolating within the database, such that target depth of infiltration is just satisfied by the minimum or low-quarter average (user choice) in the post-irrigation infiltration distribution. Management variables, once physical dimensions are given, are flow rate and cutoff time (or advance at cutoff). Each pair of values leads to a minimum depth of infiltration and a low-quarter average. With target depth assumed equal to one or the other, all performance indicators (efficiency, uniformity, percent runoff, etc.) follow. Thus, screen displays showing performance under given field conditions on a grid of design and management variables show what can be done to optimize border-irrigation performance.