The water quality classification is derived from a combination of water quality parameters and biological indicators. The ‘long term’ classification, from information collected between 2000-2007, is compared against the annual result for each site to track changes in water quality over time.
In addition, Nelson City Council monitors a network of small streams for flow and water temperature, mainly for assessing water resources outlined in the Nelson Regional Management Plan (Freshwater Plan).
Council staff have initiated a number of studies and assist communities, schools and groups to improve and maintain our waterways. For further information about Council environmental monitoring please visit Nelson City Council's website.
Nelson Rivers and streams are affected mainly by sediment resulting from land disturbance, microbial contamination associated with livestock and feral animals, and from urban stormwater in the city area.
Overall water quality is highest in the forest catchments that dominate most of the Nelson land area. It is less satisfactory in intensively farmed valley bottoms and poorest in urban streams receiving road, commercial and industrial stormwater runoff.