Changes in hydrology, sediment loss and microtopography of a vegetated mine waste rock dump impacted by fire

Dry season burning to control wildfire is conducted in Kakadu National Park in the Northern Territory. The ERA Ranger Mine is adjacent to the park, an d it is likely that at some stage the post-mining landform will be affected by fire. Rainfall simulations were conducted on a vegetated site on the mi ne waste rock dump. The site was then burnt and the rainfall simulation ser ies repeated. Initially, there was little difference between sediment loss and runoff from the vegetated condition and sediment loss and runoff from t he burnt condition. As simulations continued, total sediment loss from the burnt condition increased as a result of increasing runoff compared to the vegetated condition. Burning of vegetation affected the surface hydrology o f the site, resulting in increased erosion under saturating rainfall simila r to rainfall expected at the commencement of a wet season. Litter dams for med during runoff from the burnt condition providing areas of localized dep osition. The distribution of the dams was non-random. If fire is used as a management tool to control wildfire, placement of artificial microdams on s teep slopes may provide areas of sediment deposition and seedbank storage t o reduce the effects of elevated runoff and sediment loss and facilitate ve getation regeneration. Copyright 1999 (C) Environmental Research Institute of the Supervising Scientist/Commonwealth of Australia.