COMMAND AREA WATER DEMANDS .1. VALIDATION AND CALIBRATION OF UCA MODEL

Simulation of aggregate water demands by areas commanded by canal and lateral turnouts is an important input to the operation and management of the irrigation delivery system. A computer simulation model to pre dict these command area water-demand functions was developed and repor ted by Keller in 1987. To test the validity of the model, data from an existing irrigation project in the Delta, Utah, area were used to sim ulate the aggregate irrigation demand of five turnouts operated on a d emand basis. During the model calibration process, the influence of th ree important variables in the operation stage on the prediction of de mand was identified using the cumulative water-demand curve. The key v ariables were: (1) Management-allowable depletion (MAD); (2) irrigatio n application uniformity (IAU); and (3) initial soil moisture (ISM).