Water pollution in the West Coast Region
- acid mine drainage has significant effects on freshwater ecosystems
- less than 5% of the water samples taken from contact recreation sites indicated unsafe swimming conditions
- point source pollution has decreased and nonpoint source pollution has increased
- Water deterioration occurs at the lower levels of a number of catchments
- Water quality improvements were evident in a number of water quality indicators.
Raw sewage is discharged into the Grey River after heavy rainfall. Historically, sewage and stormwater from Greymouth, Cobden and Blaketown was discharged directly to the Grey River. Changes to the Grey District Council's wastewater schemes provide separation and treatment for sewage, except during periods of high rainfall, such as spring, when the capacity of the sewage treatment is exceeded.
Acid mine drainage
Eighty two percent of the population is supplied by reticulated drinking water with 28% having some form of treatment to improve water quality. None of the water supplies reach drinking water standards.
The water on Lake Brunner has been monitored since the 1990s and it shows that the water quality of the lake is declining.
- Horrox, J. (June 2008). "West Coast Surface Water Quality". West Coast Regional Council. Retrieved 8 August 2010.
- Bromley, Tui (31 October 2012). "Effluent with your whitebait?". The Greymouth Star. The New Zealand Herald. Retrieved 31 October 2012.
- "Environmental determinants in the West Coast". Joint report by the West Coast DHB and the CPH–West Coast. 2008. Retrieved 8 August 2010.