Shagawa Lake is a small, shallow, glacial lake.
1. Clear water
2. Eutrophic water
Phosphorus from the sewage effluent has entered the water and is stored in the sediments. The clear water has become eutrophic, with an associated reduction in species composition.
State 1 Municipal wastewater, including sewage effluent, has been discharged into Lake Shagawa from the nearby town of Ely (Population about 5,000), since the late 1800's. Phosphorus from this waste is held in the sediments; its concentration in the water increasing during the summer months.
State 2: In 1973, a tertiary wastewater treatment plant was built, reducing all external sources of phosphorus by 80%. The reduction of external phosphorus input had not reversed the anaerobic conditions by 1981, due to the internal loading of phosphorus in the sediments.
Contact
Jacqui Meyers
Email
jacqui.meyers@csiro.au
CSIRO Sustainable Ecosystems,
PO Box 284,
Canberra ACT 2601
Keywords
Pollution, biomanipulation, empirical data, model, eutrophication, water management, water quality, water resources
