Hydrological Investigations of Soil and Vegetation Types in the Lower Cotter Catchment

Abstract

SUMMARY Surface run-off and soil losses in one year from natural rainfall on 41 permanent plots were measured. Infiltration rates on the permanent plots and on 25 additional roving plots were determined with an artificial rainfall simulator. Non-capillary porosity and weight of ground cover were found to be the most important factors controlling surface run-off and soil loss. In soils with low non-capillary porosity in the subsoil, the non-capillary porosity of the surface soil varied with the amount of ground cover present. Decreases in weight of ground cover below 4,000 g/60 sq ft (2.9 tons per acre) were associated with marked increases in surface run-off and soil loss. In soils with high non-capillary porosity in the subsoil, the non-capillary porosity of the surface soil also was high and was unaffected by the amount of ground cover present. Surface run-off was low and soil loss was negligible at all times. For a given amount of ground cover, soil loss increased exponentially with rainfall intensity,...