Basslink integrated impact assessment statement potential effects of changes to hydro power generation. Appendix 25: King River instream biota assessment

Abstract

The lower King River is a highly modified environment. Upstream of the Queen River and downstream of the Crotty Dam, the lower King is affected by decreases in flows downstream of the Crotty Dam, and changes in flow regime and water quality downstream of the John Butters power station. Downstream of the Queen River junction, the King is extremely degraded by decades of pollution from acid mine drainage (AMD), mine tailings and slag emanating from historical mining activities at Mt Lyell (Koehnken 1997). The biological consequences of these impacts were described only recently (Davies et al. 1996), and this section of the river is extremely depauperate with no fish or platypus and only a residual macroinvertebrate fauna. Ongoing impacts occur due to high levels of metals, particularly copper and aluminium, sulphate and acidity. In addition, the channel has been infilled with tailing and slag sediments, which have degraded the quality of the benthic habitat and may also be toxic.