Using rainfall simulation to guide planning and management of rehabilitated areas: Part I. Experimental methods and results from a study at the Northparkes Mine,Australia

An Erratum for this article has been published in Land Degradation & Development 11(4) 2000, 399. A study using simulated rain and overland flows was carried out on a 6‐km‐long bund constructed at the NorthParkes Mine, New South Wales, Australia. The bund has been progressively constructed using 5‐m lifts to achieve final heights of 10–20 m. The slope profile consisted of alternate benches and batters of approximately 30 per cent gradient. For the topsoil placed on the bund, properties assessed included infiltration, erodibility, effects of plant cover on infiltration and erosion, and of slope length on erosion. Studies also considered permeability of the underlying spoil material, and compared susceptibility to erosion by overland flows of the two spoil materials available for bund construction. For sites that had been revegetated for one and two years, infiltration increased and soil erodibility decreased with time under vegetation. There were large increases in infiltration with increasing vegetative cover, and high infiltration rates at 100 per cent cover. The soil loss ratio curve fitted to erosion data showed larger effects of cover on erosion than predicted by the universal soil loss equation (USLE). Overland flow studies indicated no effect of slope length on erosion rates, and indicated ‘target’ levels of vegetative cover necessary to prevent rill development. Permeability of spoil underlying topsoil at one site was shown to be high, and unlikely to impede water entry and drainage. Overland flow studies showed marked differences between the two spoils studied in both critical shear for rill initiation and in rill erodibilities. Implications of the results obtained on rehabilitation planning and management are discussed. Copyright © 2000 John Wiley & Sons, Ltd.