Closing pit lakes as aquatic ecosystems: Risk, reality, and future uses

Abstract

Mine pit lakes are formed when open‐cut pits flood with water, and these lakes occur by the thousands on every inhabited continent. The remediation and closure of pit lakes is a pressing issue for sustainable development and provision of freshwater ecosystem services. While pit lakes can be spectacular examples of recreation and renewal, pit lakes may be better known for their poor water qualities and risks to communities and the environment. Often the public wants to simply “fill the pits in” to restore a terrestrial landscape, but this is not always possible. Therefore, planning for remediation and future uses is likely to provide the best outcome. Poor water quality is not necessarily a barrier to future use, although it may limit the number of uses. Short‐term future uses tend to require commercial viability, active infrastructure investment, and maintenance, and should transition to complementary long‐term uses that promote biodiversity. Long‐term future uses require relatively less ongoing maintenance beyond the initial investment and adhere to the principles that pit lakes should be safe, sustainable, and non‐polluting in perpetuity. Pit lakes will eventually develop “ecosystem values,” and the time to do so depends on the nature of the intervention and the values ascribed by the community. Where possible, closing pit lakes as sustainable ecosystems is the most realistic goal that permits a variety of future uses that is likely to see pit lakes valued by future generations.