A reservoir-routing model calibration method relating storage elements to basin geomorphology for peak runoff prediction from extreme summer storm events in ungaged arid watersheds

Abstract

A study of synthetic geomorphologic and hydrologic data has been used to determine relationships between the storage constants of a parametric storage-routing model and influential peak runoff producing parameters, allowing the direct synthesis of peak runoff hydrographs from extreme summer storm rainfall patterns. The size and drainage configurations of watershed subunit cells, termed unit areas, govern the degree of influence of dominant hydrologic parameters on simulated peak flow. As unit area size increases, channel slope and overland slope parameters increase in their apparent effect on peak flow. Roughness parameters and channel width do not show such a trend. A calibration method for a simple and complex drainage configuration of an optimum size 0.5 square mile unit area was developed by combining dominant slope factors into one variable and relating this variable to rainfall intensity to define equivalent cell storage constants. The calibration method was tested with actual hydrological data available for various arid watersheds with limited success.