The West Coast has a large number of lakes. Many of these have important aesthetic and recreational values and it is necessary that these are maintained for future generations. The West Coast Regional Council currently monitors two lakes throughout the year (Brunner and Haupiri) and another lake (Mahinapua) is also monitored for contact recreation suitability over the summer months.
The West Coast has many lakes however most are located in unmodified bush catchments with little anthropogenic inputs. The quality of lakes is strongly related to their depth and the types of land use and activities in the surrounding catchment. Lake Brunner and Lake Haupiri have been identified as the most vulnerable due to significant land modification and human settlemts in their catchments. These lakes have aesthetic and recreational values that need to be maintained. Lake Brunner has been monitored since the early 1990's and Lake Haupiri since 2011. Both are considered to have good water quality although Lake Brunner water quality has declined since 1992. In the past when data from the entire record has been analysed, there have been important deteriorating trends for a number of parameters. Many of these trends are no longer apparent, except for nitrate, total nitrogen and dissolved reactive phosphorus.