Improving Farm Irrigation Systems by Automation

Automation can make surface irrigation more attractive to the irrigator by reducing labor and energy requirements. Where lands and soils are well suited for surface irrigation, it is often more economical to improve surface systems than to convert them to energy intensive systems requiring many times more energy. Canal systems need to be improved to facilitate on-farm automation by providing water on demand at the farm turnout. Improvements required to partially satisfy this need include: greater use of automatic control facilities, increasing the storage capacity of the system by constructing small regulating reservoirs and providing additional freeboard, improving turnouts to allow acceptance or rejection of the farm delivery, and improved water-measurement devices to measure water volumetrically. Where these improvements are not made, small farm reservoirs may be needed to provide water on demand and to facilitate automation of the farm system. Many surface systems can be improved by replacing open - ditches with buried pipelines and gated surface pipe. Systems with pipelines can be improved by using automated valves and controls with existing facilities. Both programable controllers and manually reset timers can be used for either fully automatic or semiautomatic operation. Runoff was reduced about 45 per cent on experimental test plots using cutback furrow irrigation streams. Less water was applied with timer-controlled, semiautomatic irrigation than with manual irrigation. This resulted in higher production efficiencies in terms of crop yield per unit of water applied. Irrigation efficiencies with present systems having long lengths-of-run can be improved by using either surface or buried pipe laterals to divide the total field length into two or more subruns. This is usually not practical unless the system is automated

Flo-Thru Gated Pipe May Lower Cost

With increasing energy and labor costs, irrigators are looking for ways to minimize costs and at the same time use their water more efficiently. One system used quite extensively during the past two or three years in the Grand Valley of Colorado is the semiautomated "flo-thru" gated pipe system. This system uses a single gated pipeline for a number of irrigation sets without the irrigator having to close one group of gates and open another group at each irrigation set change

Surface Irrigation Can be Automated

THE WATER control facilities and management practices that farmers use significantly affect the amount of irrigation water used. Mechanized surface irrigation systems using automated control structures enable the farmer to apply water more efficiently and with a minimum of labor. Ideally, these structures automatically stop irrigation on one portion of a field or farm and direct the water to another section as required

Energy Dissipation in Low Pressure Irrigation Pipelines: II Orifices

Erosion caused by water discharged from gated pipe openings can be reduced by dissipating excess energy with orifices placed in the gated pipe couplings. Laboratory tests were conducted to determine graphical relationships and coefficients for estimating the head loss for orifices made from galvanized sheet metal. The loss coefficient, Ko, is a function of the orifice-to-pipe diameter ratio, ?o, and can be expressed by an equation of the form Ko= a?bo where a and b are empirical constants determined from the tests. Comparisons made between machined, square edge orifices commonly used for flow measurement, and those made in sheet metal shops for irrigation showed that the irrigation orifices have a higher discharge coefficient and a lower head loss coefficient than do the square edge orifices. Square edge orifices placed in irrigation pipe couplings behaved similarly to those for flow measurement, particularly in the mid and lower ranges of the diameter ratio, ?o. The head loss ratio, R, as defined by the ASME (1959) is the same for, (a) square edge orifices used for flow measurement, (b) square edge orifices installed in aluminum irrigation pipeline joint couplings, and (c) sheet metal orifices made for irrigation installed in pipe couplings. The ratio can be represented by the equation R=1-0.9 ?o 1,7

Automated Single-Pipe Systems for Conveyance and Water Distribution

An advantage of gated pipe for irrigation is that it can be used both for water conveyance and water distribution. A single gated pipeline is normally used for a number of irrigation sets and this requires that one group of gates be closed and another opened at each irrigation set change. Since this requires considerable labor, different methods of automation are being developed to minimize the labor requirement. In most automated gated pipe systems, a separate pipeline is used for conveyance while the gated pipe is used only for distributing water to the field. The supply pipe is either buried or placed on the surface and has automated valves attached to risers or outlets located along its length. This constitutes a double-pipe system

Energy Dissipation in Low Pressure Irrigation Pipelines. I. Butterfly Valves and Discs

EROSION caused by water discharged from gated pipe openings can be reduced by dissipating excess energy with orifices placed in the gated pipe couplings. Laboratory tests were conducted to determine graphical relationships and coefficients for estimating the head loss for orifices made from galvanized sheet metal. The loss coefficient, Ko, is a function of the orifice-to-pipe diameter ratio, ?o, and can be expressed by an equation of the form Ko = a?bo where a and b are empirical constants determined from the tests. Comparisons made between machined, square edge orifices commonly used for flow measurement, and those made in sheet metal shops for irrigation showed that the irrigation orifices have a higher discharge coefficient and a lower head loss coefficient than do the square edge orifices. Square edge orifices placed in irrigation pipe couplings behaved similarly to those for flow measurement, particularly in the mid and lower ranges of the diameter ratio, ?o. The head loss ratio, R, as defined by the ASME (1959) is the same for, (a) square edge orifices used for flow measurement, (b) square edge orifices installed in aluminum irrigation pipeline joint couplings, and (c) sheet metal orifices made for irrigation installed in pipe couplings. The ratio can be represented by the equation R=1-0.9 ?o 1.7

Surge Irrigation: 1. An Overview

Soil infiltration rates are generally reduced by the intermittent application of water during surge irrigation such that this technique can be used to increase the wetting front advance compared to continuous flow and to control runoff. Surge flow principles related to water advance and infiltration in furrows are summarized. Computer models to simulate surge flow irrigation are noted, particularly the kinematic wave model which has become the standard for surge irrigation. Commercial valves and controllers are available for automating surge irrigation systems. Field test results with different soil and field conditions at a number of locations are discussed. Results have varied but show that the greatest effect on infiltration rates occurs during the advance phase on light-textured soils and during the first irrigation of the season or following tillage

Automatic Controls for Surface Irrigation Systems

Automatic irrigation controls, such as gates, checks, valves, timers, soil moisture sensors and related devices, are described. These increase worker productivity and give better control of farm irrigation water. Most semiautomatic irrigation systems use mechanical timers to control irrigation and its duration, whereas automatic systems use sensors and programmed timers. Automatic and semi-automatic gates and checks are used in open channel systems to divert water through different kinds of openings. Low pressure valves and controls are being developed and tested for automating gated pipe systems

Surge Irrigation: 2. Management

General management guidelines for using surge irrigation to improve irrigation efficiency are summarized. Furrow irrigation is managed to complete the advance phase with a minimum volume of water using non-erosive streams. The post-advance phase is managed to prevent excessive runoff and to satisfy irrigation requirements of the root zone. Three methods of managing the post-advance phase are discussed. Improving irrigation efficiency with surge irrigation can, in some areas, help control vector-born diseases by reducing pools, puddles, seepage areas, and the use of low-velocity unlined ditches with their associated aquatic vegetation

Automatic Irrigation

Automatic or mechanical irrigation structures can be used to surface irrigate all or part of many Idaho farms without extensive modification of present systems. The available water may be stretched by use of timer-controlled irrigation structures which automatically terminate irrigation on one portion of a field or farm and direct the water to another area