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

Authors

  • K. G. Evans,

    Corresponding author
    1. Erosion and Hydrology Group, Environmental Research Institute of the Supervising Scientist, Locked Bag 2, Jabiru, NT 0886, Australia
    2. Department of Civil, Surveying and Environmental Engineering, The University of Newcastle, Newcastle, NSW 2308, Australia
    • Locked Bag 2, Jabiru, NT 0886, Australia.
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  • M. J. Saynor,

    1. Erosion and Hydrology Group, Environmental Research Institute of the Supervising Scientist, Locked Bag 2, Jabiru, NT 0886, Australia
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  • G. R. Willgoose

    1. Department of Civil, Surveying and Environmental Engineering, The University of Newcastle, Newcastle, NSW 2308, Australia
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  • Reproduced with permission of the Commonwealth of Australia.

Abstract

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, and 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 mine waste rock dump. The site was then burnt and the rainfall simulation series repeated. Initially, there was little difference between sediment loss and runoff from the vegetated condition and sediment loss and runoff from the 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 of the site, resulting in increased erosion under saturating rainfall similar to rainfall expected at the commencement of a wet season. Litter dams formed during runoff from the burnt condition providing areas of localized deposition. The distribution of the dams was non-random. If fire is used as a management tool to control wildfire, placement of artificial microdams on steep slopes may provide areas of sediment deposition and seedbank storage to reduce the effects of elevated runoff and sediment loss and facilitate vegetation regeneration. Copyright © 1999 John Wiley & Sons, Ltd.

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