Scale-dependent soil and climate variability effects on watershed water balance of the SWAT model

摘要: Abstract The water balance of large watersheds in Texas was studied using a process level watershed model called the soil and assessment tool (SWAT). major components SWAT are evapo-transpiration (ET), storage (SW), yield (WYLD), which is sum surface runoff subsurface flow. Important input variables controlling soils climate. In this paper, changes mean variance due to variability climate were assessed for six different (Hydrologic Cataloging Units, HCUs) covering wet semi-arid regions 1:250,000 scale data. Bulk density, available capacity, moist albedo selected as parameters. Soil heterogeneity defined terms textural classes triangle. Spatial precipitation between neighboring weather stations quantified power spectra. impact geographic scales on determined by studying Seco Creek sub-watershed within Hondo HCU 1:24,000 Results from observation show that SW high function increasing 1:24,000, while ET sensitivity remained about same. direct influence properties such bulk ET, SW, WYLD equal when For composed heterogeneous (loam fine sands sandy loams), means relatively sensitive variability, heterogeneity. Watersheds shallow showed capacity. Changes suggest presence scale-dependent ‘uncertainty’ laws.