The NZ Federation of Freshwater Anglers has reported on a serious decline in water quality in the South Island's Canterbury region.

And the root of the problem? "The major causes were over-takes of water by irrigation and excess nutrients from excessive and intensive dairying which resulted in a grossly polluted source aquifer contaminated by 48,000 ha of irrigated dairy farming ... "

See https://nzffa.com/canterburys-river-...ction-anglers/