Seasonal river flow-through as a pit lake closure strategy: is it a sustainable option in a drying climate?
School of Science/ Centre for Ecosystems Research
River flow-through has been used to effectively close pit lakes, however much of the evidence for this comes from permanent rather than seasonal rivers. Lake Kepwari (a former open-cut coal mine in Western Australia) was connected to the seasonal Collie River for closure. River water improved lake water quality but the lake caused varying downstream hydrological and chemical changes. Consecutive years of low rainfall resulting in low lake water levels could delay or reduce downstream flows and increase lake acidity. Using seasonal rivers as sources of flow-through presents a riskier scenario than using permanent rivers, particularly in a drying climate.