Clean rivers come at a cost
WELLINGTON: Improving the ‘‘swimmability’’ of New Zealand’s rivers by just 7% could cost more than $200 million each year, a new analysis has found.
The report, published by the Ministry for the Environment, looked at work under way in the regions to meet water quality standards set by the previous government. The main goals were to improve water quality across all areas, and make 80% of rivers and lakes suitable for swimming by 2030, and 90% by 2040.
A ‘‘swimmable’’ waterway was considered one that fell inside the best three of five baseline categories.
It meant that the average risk of infection from E.coli was as low as 1% to 3%, and the health risk from cyanobacteria in lakes ranged from moderate to no different from natural conditions.
Going by that measure, 71.2% of the country’s lakes and rivers were at present ‘‘swimmable’’, while 68.6% of rivers only were deemed safe for a swim.
Auckland, Northland, Waikato, Taranaki and ManawatuWhanganui had the worst overall rates of swimmable rivers, at 23%, 24%, 37%, 39% and 43% respectively.
Marlborough, Nelson, Tasman, the West Coast and the Bay of Plenty all had the best rates, ranging between 95% and 100%.
The new analysis suggested that if committed work around the country was completed — and that included proposals for stock exclusion — New Zealand’s swimmability would rise to 76% for rivers and 78.1% overall.
But it would come at a big cost. An economics assessment put the annual cost involved at $217 million, $13 million of which would be borne by the rural sector.
The sheep and beef sector would meet 59% of that and dairy, dairy grazing, deer and lifestyle farms would contribute 16%, 3%, 3% and 19% respectively.
The higher cost for sheep and beef farming was due to the current low level — and the price — of stream fencing on that type of land.
Other factors included the need to invest in water reticulation following stream fencing to give livestock access to water, and the generally large area used.
The cost would be even higher if sheep had to be excluded from streams as well.
By region, the biggest contribution to that cost — about 40% — would come from Auckland, where most of the population lived, and where large commitments had been made to improve wastewater.
Canterbury would shoulder around 15% of the cost and Waikato would contribute 9%. — NZME