Design of Irrigation Runoff Recovery Systems

Abstract

A technique is presented to design Irrigation Runoff Recovery Systems (IRRS) to recover runoff water from furrows and to increase irrigation efficiency. The method permits using a constant inflow to all furrows throughout the entire irrigation, requires changes in set size only twice, permits using a constant discharge from the pump once it is turned on, and uses all the water applied to the field, i.e., there is no net runoff from the field. This is accomplished by irrigating the entire first set from the inflow water and collecting the runoff in a storage reservoir. All of the remaining sets, except the last one, are irrigated by both the supply stream and the runoff water, recirculated by pump, and the last set is irrigated entirely by pumped runoff water. To simplify the design procedure, equations have been developed to determine the number of irrigation sets, the number of furrows irrigated with recovered runoff water, the recirculating-pump flow rate, and the volume of the storage pond required.