Pressures on water quality in Southland are from agricultural development and intensification, as well as from urban development including industrial and wastewater discharges.
Environment Southland monitors 76 water quality sites around the region to assess the state and trends of water quality and risk to community from swimming. Most sites are located in hill country and lowland catchments, with fewer sites occurring in natural state areas.
Water quality is generally excellent in natural state areas such as Fiordland and Stewart Island. However, many lowland rivers and streams show elevated levels of nutrients. Many lowland streams' bacterial loadings are above the national and Regional Water Plan standards. Water clarity is acceptable in most monitored catchments, with the exception of streams with naturally diminished clarity, such as those draining peat swamps or tannin-stained catchments. These streams often have naturally lower dissolved oxygen and pH levels.