This paper reports computer simulations carried out using data from a rainfall simulator study on a steeply sloping revegetated area (a soundbund) at the NorthParkes Mine, near Parkes in New South Wales, Australia.
Simulations of slope stability used a combination of daily time-step models to consider soil water balances and runo, growth of grass/legume pasture and soil erosion. Simulations indicated that long-term erosion rates on the soundbund would be low (1 . 01Β±1 . 27 t ha Γ1 yr Γ1 ) due to low runo rates and good vegetative cover. The simulations highlighted that peak vegetative growth occurred prior to the period of peak erosion hazard, with carry-over dry matter being crucial for erosion control during the period of peak rainfall erosivity. This, in turn, indicated that grazing during the periods of peak growth and peak erosion hazard should be avoided (to avoid loss of dry matter). It also indicated that there was value in establishing grass species that would give greater growth during summer months, and that may produce dry matter that is more persistent through time.
Simulations of stormwater Β―ows in channels draining various lifts on the soundbund compared a range of alternatives with respect to channel length, gradient and roughness. The simulations indicated little eect of channel length on peak Β―ow rates or depths once channel lengths exceeded 250 m and also showed little eect of vegetative roughness on peak Β―ow rates or depths once Manning's n values exceeded 0 . 05. Implications of these results for design of drainage channels and drop structures on the soundbund are discussed.