Hydrology and Bauxite Mining on the Darling Plateau

Abstract

Abstract A review was undertaken of the interaction between bauxite mining, its restoration, and the hydrology of the Darling Plateau. Alcoa’s mining operation is predominately within the water supply catchments of Perth, giving rise to three hydrological issues: turbidity, stream yields, and stream salinity. Turbidity management is effected through attention to detail in day‐to‐day operations. Due to the high rates of evapotranspiration, yields from Jarrah forest catchments are low by normal standards, varying from 25% of rainfall in the highest rainfall area to less than 1% of rainfall in the lowest; this has been further exacerbated by the below‐average rainfall since 1975. These low yields have resulted in increased interest in stream yields from mined and restored mine areas and how these may be maintained compared with unmined forest. Under current rainfall regimes, it is unlikely that there will be a significant salinity response due to Alcoa’s mining, but it is inadvisable to discount the salinity issue in the lower rainfall zone, and research will need to consider the possibility of further climate change.