Parameter optimization for simulating semiarid watershed hydrology

Successful parameter optimization would be valuable for correlations with watershed treatments or for regionalization for ungauged watersheds. A digital watershed model capable of simulating surface runoff hydrographs from small desert watersheds was developed from previous modeling studies. Six parameters were selected for optimization. All other parameters were estimated from previous studies or were measured on the watershed. The model was calibrated with data from a 14 acre watershed in the Tucson Basin. Independent data from the same watershed and data from a similar watershed were used to validate the calibrated parameter values. Calibration was carried out by an optimization strategy of response surface identification, followed by extensive surface climbing and concluding with a quadratic convergent fitting.