Episode 14: Precious Water
A harsh summer of drought and a series of environment court battles over irrigation rights have focussed attention on water as one of the biggest issues facing the country.
On top of that, many once-popular swimming holes are no longer safe - so New Zealanders can no longer be smug about our "clean green" image.
But there are bright spots. The community living along Nelson's Motueka River is making an attempt to create change. A wide range of researchers, users and interest groups are working together on an ambitious project called Integrated Catchment Management.
Country Calendar this week meets some of the scientists and users of the river to find out what they've discovered and what's being done to clean it up.
The Motueka is one of the world's premier brown trout fisheries - but its water is also in demand for irrigation by farmers and horticulturists.
It flows through one of the largest forestry estates in the country and is also loved by locals for swimming and recreation - and what happens upstream affects fishermen and marine farmers many kilometres offshore in Tasman Bay.
Scientists from Landcare Research, Otago University, the Cawthron Institute and other organisations have combined to study every detail of the river system, from high in the mountains through a variety of different landscapes and out into the sea beyond the river mouth. They now have a detailed knowledge of the catchment and a better understanding of the many influences on water quality.
At the same time, the different users have worked to minimise the harmful affects of their enterprises. In plantation forests, logging and roading have been modified to lessen the effect of sediment. Dairy farmers have put in bridges to keep their cattle - and their waste - out of the water.
Irrigators have accepted limits on the amount of water they use so that minimum flows are maintained to protect fish. And careful attention is now paid to how much gravel is extracted by road builders and the like.
It's a long, gradual process, but the water quality is improving. For example, one of the Motueka's tributaries, the Sherry River, used to be too polluted for swimming - now it's nearly swimmable again and farmers are working together to replant its margins with native trees and shrubs.
Scientists are now developing computer models so they can predict what effects future developments will have, not only on water quality but also on the economy of the region. And they're hoping what they've achieved in the Motueka will be an example which can be followed on other rivers around New Zealand.
Other sites to view:
- For more information on the Motueka Integrated Catchment
Management scheme, go to http://icm.landcareresearch.co.nz or www.maf.govt.nz/mafnet/publications/rmupdate/issue-18/rm18-06.htm
- For info about fly fishing on the Motueka River, go to www.nzfishing.com/FishingWaters/NelsonMarlborough/NMFishingWaters/NMMotueka.htm