Spatial variability of hydrologic response on naturally vegetated hillslopes in a semi-arid environment.

Abstract

Application of discriminant analysis to the soil/slope data validated the landsurface unit classification and identified the most useful mapping criteria. Seven variables measuring soil depth, soil texture, microroughness, and the areal percentage coverage of bare/eroded micro soil surfaces provided satisfactory discrimination of the six soil/slope groups.

The hypothesis examined in this study suggests that spatial variability in overland flow and sediment yield on hillslopes in a semi-arid environment are related to the spatial distribution of specific soil/slope characteristics. Analysis of overland flow, sediment yield, and soil/slope data supports the research hypothesis by validating the field classification of erosional and depositional landsurface units, and in identifying distinctly different hydrologic responses between two landsurface units on three separate catenas.

Four measures of hydrologic response were used to test for differences in overland flow and sediment yield between the landsurface units; overland flow response to individual rainfall events, sediment yield from individual rainfall events, total sediment yield for the six year period of recording, and rainsplash efficacy. All four attributes substantiated the hypothesized relationships.