Spatial storm characteristics and basin response

Abstract

Spatial thunderstorm rainfall properties that are generally regarded as important in runoff production were studied over a range of basin scales within the USDA-ARS Walnut Gulch Experimental Watershed. Various storm geometric measures were computed from a fine 100 x 100 m grid via interpolation. Multiquadric and kriging interpolation methods were compared yielding similar results. The multiquadric method was selected for further interpolation due to its ease of application. Regression techniques were then employed to relate storm measures to watershed runoff. The spatial portion of storm having comparatively higher intensities (>25 mm/hr) was found to be responsible for much of the runoff. The other important factors are storm area and duration. The study did not find evidence that the spatial storm location or antecedent watershed wetness influenced the runoff response in a consistent fashion. The antecedent channel wetness was found to have moderate influence for the largest of the three watersheds investigated.