Abstract
Bauxite mining occurs over an extensive area of the northern jarrah forest within water supply catchments for Perth and the south-west region. The hydrologic impact of mining and subsequent rehabilitation have been monitored at two experimental catchments, More Seldom Seen and Del Park. Based on comparison to native forest control catchments the groundwater, streamflow and stream salinity response to mining were observed. The major response to mining was a significant increase in streamflow. The maximum streamflow increases were 8-20% of annual rainfall (160-240 mm), and were related to the area of catchment mined. Groundwater levels rose by a maximum of 2-4 m. Both groundwater levels and streamflow increases declined as the mined areas were rehabilitated. There was a slight increase in stream salinity. However it was not significant. The hydrologic impact of mining and rehabilitation was of similar magnitude as that of temporary land use changes such forest logging or thinning in south-west Australia.