Water temperature and clarity - retrospective information
A review of some of the water resources information collected by NIWA across New Zealand.
River water temperature, January-March 2010
River water temperatures were mostly typical for this time of year, with the usual latitudinal pattern (river temperatures tend to decrease north-to-south) complicated by an altitudinal effect (temperatures of upland and alpine rivers tend to be comparatively low). The Wairau River in Marlborough was appreciably cooler than in a typical summer.
River water clarity, January-March 2010
Rivers were clearer than normal over much of the country, but particularly in the South Island, with several highest-ever visibility records including the Haast River, south Westland. The higher than normal visual clarity probably reflects lower than normal river flows - again particularly in the South Island.