April 21, 2014
Toxic chermistry blights dam project
Forest and Bird says it will be hard to make an economic case for the Ruataniwha water storage scheme now because of the conditions imposed by a board of inquiry.
The project to irrigate land round Waipawa and Waipukurau is being promoted by the Hawkes Bay Regional Council, but it drew opposition from environmental groups and some of Ngati Kahungunu.
Forest and Bird advocacy manager Kevin Hackwell says the scheme’s promoters tried to argue that only phosphorus in the water needs to be monitored.
The board ruled that nitrogen must also be kept below acceptable levels.
That’s a critical piece of chemistry for people who want to swim or collect kai from the rivers downstream of the dam.
"People walking their dogs beside the river in some parts of the country at some times of the year, if the dog just sniffs or licks some of the algae on the side of the river they could be killed, and that’s because we’ve got these very high levels of the nutrients phosphorus and nitrogen and together when they are in the right sort of proportions, the algae just goes crazy. It can get to the point of being toxic. It can certainly get to the point of taking out so much oxygen from the water that the fish and the other things can’t survive. When you intensify agriculture you end up putting a lot more of these nutrients back in the water, and then you end up killing the life force of the rivers," Mr Hackwell says.
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