Kiwis “must be vigilant” about swimming in our rivers, a freshwater scientist says, with data often showing high levels of E. coli in waterways.
A Herald investigation last week revealed how samples taken from two Auckland spots were well above levels of the key faecal indicator that would be considered safe for swimming.
But a study by the National Institute of Water and Atmosphere (NIWA) shows that’s a regular occurrence in rivers around the country.
A recent analysis of 928 spots tested between 2009 and 2013 showed that all urban sites exceeded the minimum acceptable state for “primary contact” like swimming, as set out by the Government’s National Policy Statement for Freshwater Management.
This threshold was also crossed at 91 per cent of pastoral sites, 46 per cent of exotic forest sites and 29 per cent of “natural” areas of native forest.
About half of New Zealand’s river length is fed by catchments that are mainly influenced by indigenous land cover, while 45.7 percent are influenced mainly by pasture, 5.1 percent by exotic forest, and 0.8 percent by urban land cover.