Post-mining landform evolution modelling: 1. Derivation of sediment transport model and rainfall-runoff model parameters

Abstract

Data were collected from three sites on the waste rock dump at ERA Ranger Mine: (1) the cap site which was unvegetated and unripped with a surface slope of 2·8 per cent; (2) the batter site, surface slope 20·7 per cent, also unvegetated and unripped but with a covering of coarse rock material; and (3) the soil site, surface slope 1·2 per cent, which had c. 90 per cent vegetation cover of low shrubs and grasses and had been topsoiled and surface ripped. Natural rainfall events were monitored on the sites to collect rainfall, runoff and soil loss data to parameterize a sediment transport model of the form T = β S ∫ Q dt, and the DISTFW rainfall–runoff model. Low frequency, high intensity events resulted in the greatest soil loss. To accurately predict sediment loss during high intensity events, storms with a range of intensities were selected to derive the sediment transport model. DISTFW hydrology model parameters were derived by fitting four monitored events simultaneously. The selected parameters for the vegetated and ripped case may overpredict discharge for some rainfall events resulting in conservative design of erosion control features on rehabilitated landforms. Copyright 2000 © Environmental Research Institute of the Supervising Scientist, Commonwealth of Australia.