Accelerated Irrigation Canal Flow Change Routing

Abstract

In a traditional automated upstream controlled canal with a downstream buffer reservoir, the process to fill the buffer reservoir requires one step: the inflow to the canal is increased, and the flow change eventually arrives at the buffer reservoir. This paper describes an attempt to shorten the time necessary to stabilize the new flow rate at the buffer reservoir. The method requires calculated, remote manual adjustments to all the canal check structure gate positions in addition to two flow rate changes made at the head of the canal, followed by a return to automated upstream control. The method was tested in the Upper Main Canal of the Central California Irrigation District both through simulation and in the field. With a canal flow of approximately 2% of the maximum, simulation modeling predicted that a flow rate change arrival at the reservoir would be about 5.5 h in a typical operation, with final stabilization in about 16 h. Simulation of an improved procedure indicated an almost instantaneous increase in flow at the reservoir of half the flow change, with final flow stabilization at 11 h. The field test resulted in almost the full flow change arriving at the reservoir after about 2 min, with gradual stabilization occurring over the next 11 h. Important differences between simulation and actual results are discussed.