Presented at Contemporary challenges for irrigation and drainage: proceedings from the USCID 14th technical conference on irrigation, drainage and flood control held on June 3-6, 1998 in Phoenix, Arizona.Metering of farm water deliveries in the Imperial Irrigation District has always been a costly and difficult procedure. Due to existing structural and environmental conditions, many of the traditional methods of metering deliveries had in the past proved cumbersome or unsuccessful. With funding provided by the IID/MWD Water Conservation Program, a method for utilizing ultrasonic transducers for metering farm water deliveries under orifice flow conditions has been developed. These on-farm water level sensors were designed to be portable, environmentally rugged, solar powered, simple to operate and maintain, and visually unobtrusive to minimize vandalism. This paper describes the construction of the on-farm water level sensors and their function as a useful tool in providing rapid and accurate irrigation evaluations to farmers
