Sad to relate, but the dairy industry has done it again. In June 2019 the NZ courts have imposed record fines on corporate dairy farmers for river pollution: see Radio NZ report at https://www.rnz.co.nz/news/national/391409/dirty-dairying-effluent-spills-lead-to-record-taranaki-fines-for-farming-companies
Dairy industry leaders refuse to admit there is a problem. Instead they are trying to fool the public by running a massive media blitz in a vain attempt to show farming is environmentally friendly.
See also https://www.rnz.co.nz/programmes/water-fools
Visiting fly fishers are catching on to the decline in fishing quality. Howard West, writing in FlyLife magazine # 95, says "New Zealand - better go soon" (http://www.nzffa.co.nz/stories/better_go_soon.html)
Update 29 August 2019: see also "The Incontinent Cows of Middle Earth", a NY Times article by Professor Mike Joy, a freshwater scientist. (The link is https://www.nytimes.com/2019/08/15/o...land-cows.html).
The effect of farming on NZ waterways can be seen in the video clip https://www.youtube.com/watch?v=IbfiqRj1EME
Update, 8 Sept 2019: the NZ government has announced water management reforms to clean up our dirty rivers. This will require damaging farming practices to cease in some areas, so it will naturally be opppsed by the rural industry lobby.
See https://www.stuff.co.nz/environment/115517275/the-tab-for-decades-of-water-mismanagement-is-falling-due
Update 23 Jan 2020: further evidence of deteriorating water quality (toxic algae) in New Zealand fisheries: "Farmers are ruining Canterbury's rivers" at http://norightturn.blogspot.com
No word yet on what moves the government will make with its water protection proposals, which were the subject of public consultation last year (see the "Save our Streams" thread). 2020 is an election year, so Kiwi anglers will be making their voices heard.
With Australia on fire and parts of NZ threatened by drought, water is our most valuable resource.
Update 30 January 2020: more bad news for rivers in New Zealand. A news report states that Southland's Waikaia river contains toxic algae. This is the side of New Zealand the tourist industry doesn't want visitors to see. Check out https://www.es.govt.nz/about-us/news...mcr17q9sc0m33v