Recent Past President of Federated Farmers, Dr William Rolleston, thinks there may have been too much hype over the Labour water levies proposal.
He writes "The average amount of rain across NZ (from what I can tell from the stats) is 600-1600mm.
So at 1100mm and 27 million hectares that’s:
1.1 metres rainfall x 27 million hectares = 29,700,000 x 10,000 (m^2/hectare) x 1,000 (litres/cubic metre) = 297,000,000,000,000 litres.
@ 2c/m^3 Labour expect to raise $100,000,000 which would imply that there is 5 million million litres (50 million m^3) being used for irrigation or 1.6% of NZ water.
That sounds about right.
Here is the amount each province will pay in tax based on the Irrigation New Zealand Research Report - Industry Snapshot
If you compare this to the assessment of river swimmability there seems to be an inverse relationship between the overall state of the rivers in a province and the tax take.
Canterbury and Otago look among the best with Northland and Gisborne amongst the worst. I suppose that makes sense as the areas with the most irrigation are those with the most water in their rivers – West Coast the exception of course.