Assessing Soil Remobilisation in Catchments using a ^sup 137^Cs-sediment Hillslope Model

• Published in: Australian geographer Vol. 39; no. 4; p. 445
• Main Authors: Simms, Ava D, Woodroffe, Colin, Jones, Brian G, Heijnis, Henk, Harrison, Jennifer, Mann, Rob A
• Format: Journal Article
• Language: English
• Published: Sydney Taylor & Francis Ltd 01-12-2008
• Subjects: Creeks & streams; Reservoirs; Sediments; Soil sciences; Soils; Water supply; Sydney New South Wales Australia
• ISSN: 0004-9182; 1465-3311

Soil redistribution studies are important, especially in water supply catchments, because the rate at which denudation is occurring has implications for offsite water quality. However, the extent to which soil is redistributed within the landscape can be difficult to determine. This challenge can be overcome using fallout caesium-137 (...). This paper describes the rates of soil loss and remobilisation in two sub-catchments within the Sydney Basin region, namely Kembla and Kentish Creeks, which drain to the Cordeaux reservoir. The total inventories of ... in catchment soils were determined, a ...-regression equation and a theoretical diffusion and migration model were used to established relationships between ... inventories and the rates of soil loss. These relationships revealed relatively low occurrence of soil loss in Kentish Creek, but two slopes in the Kembla Creek sub-catchment had losses that appear to be moderate. However, there was no clear evidence to suggest whether slopes in upper and lower reaches of catchments had specific patterns of soil remobilisation. Qualitative categorisation of the slope elements using a ...-sediment hillslope model can be a useful sentinel for land users and decision makers even if absolute rates of soil loss or gain are not certain. The findings suggest that sediments mobilised in the study sub-catchments are not likely to impact significantly on the water quality in the Cordeaux reservoir. (ProQuest: ... denotes formulae/symbols omitted.)