How representative are pit lakes of regional natural water bodies? A case study from silica sand mining.
International Mine Water Association
Faculty of Computing, Health and Science
School of Natural Sciences / Centre for Ecosystem Management
In many regions, regulators view pit lakes akin to natural lakes and impose similar guidelines for water quality and biodiversity. At Kemerton (south Western Australia), extraction of silica sands is creating a large deep dredge pond. This is progressively split into smaller lakes, which are then rehabilitated. The water quality and macroinvertebrate communities of a rehabilitated pond, 3 other artificial wetlands, and 13 nearby natural wetlands were investigated. Catchment rehabilitation has successfully returned some terrestrial vegetation, however the pond edge lacked a developed riparian zone. Species diversity and abundance was substantially lower (≈ 50% and 10% respectively) than in natural wetlands. Overall the macroinvertebrate communities and water quality of artificial wetlands were significantly different to the natural wetlands.