The Nelson City Council is a unitary authority which combines the functions of both a city council and Regional Council. Its area extends from Waimea Inlet to Cape Soucis along the eastern margin of Tasman Bay in the northern South Island. It covers approximately 42,000 ha.
Anyone who has approached Nelson by sea or air will be aware that Nelson City is located at the head of Tasman Bay and surrounded by mountainous terrain. This is one of the main influences on the shape of the city. Most of the population lives in the city centre and its suburbs. The surrounding rural area is sparsely populated. Rural valley floors and lower slopes are mainly used for agriculture, but the number of lifestyle blocks is increasing. The rest of Nelson’s terrain is either plantation forest or protection native forest.
Only 6% of the land area of Nelson City’s region is an urban environment of houses, factories, shops and parks. Crop and farm land cover a further 13%. The remainder of the land cover is in forest, shrub land or grassland.
Exotic production forest accounts for 22%, native forest 34% and regenerating kanuka on hill slopes covers a further 8%. Areas of gorse and other exotic woody vegetation cover 6%.
Māori lived in the area as early as the 13th century, and by 1850 1,000 Europeans had settled in the area. In 2006 the population was 44,300 and it is expected to rise to around 50,000 by 2026. Nelson’s population has increased by 1.2% per year over the past 10 years and the urban area contains the largest settlement in the upper South Island.
Nelson City Council operates a network of 28 river ecology monitoring sites including many on small streams within the urban area. Sites are monitored four times a year for a range of tests with biological monitoring undertaken once a year in early summer.
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 www.nelsoncitycouncil.co.nz/environment.
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.