Wellington sewage : An environmentally acceptable solution

Forest and Bird, Volume 19, Issue 1, 1 February 1988, Page 17

Wellington sewage : An environmentally acceptable solution

Wellington and Hutt Valley sewage pollutes 1500 ha of coastal waters around the entrance to Wellington Harbour. Raw sewage is discharged at Moa Point from much of Wellington City and milliscreened raw sewage from the whole of the Hutt Valley is discharged opposite at Pencarrow. But as Lower Hutt branch member Russell Bell reports, a combined approach could solve the problem.

ewage is a hot political issue in Wellington. In 1986 it led to the downfall of sitting mayor Ian Lawrence because he would not make a commitment to landbased secondary treatment. Wellington residents have twice voted for secondary treatment for their sewage and a Hutt Valley Drainage Board survey in 1986 showed almost 70 percent of Hutt Valley residents favoured land-based secondary treatment. With its mandate, the Wellington City Council is now pushing ahead to find a suitable treatment plant site. But by contrast the Hutt Valley Drainage Board seems determined to proceed with a long outfall for raw sewage. Wellington City Council's consultants have narrowed the possible sites down to two, either Karori Stream, south-west of Wellington, or Gollans Valley, on the eastern side of Wellington Harbour. For sewage to go to Karori Stream, the pipeline would have to cross the active Wellington fault and a coastal scientific reserve. The Gollans Valley site also has its difficulties: the pipeline would have to go under Wellington Harbour, and the original plans placed the treatment plant directly above the finest freshwater wetland in the region. The wetland stretches 3 km up Gollans Valley from Lake Kohangatera, its dense raupo and flax swamp the home of bittern, spotless crake, grey duck, pukeko, and other waterfowl. Many large eels, giant kokopu and other native fish are found there. For many years the Lower Hutt branch has been trying to achieve protection for this magnificent area. After studying the problem, a group of Lower Hutt and Wellington Forest and Birders have found an environmentally acceptable site: Wry Valley, a side valley of the main Gollans Valley. It has a number of advantages: ® There is sufficient area for treating both Wellington and Hutt Valley sewage; @ It is cheaper than a long outfall for Hutt Valley sewage; ® The surrounding bush and farmland could be bought for a 3000 ha Regional Park to complement existing bush reserves behind Eastbourne. Forest and Bird’s Wry Valley site has the endorsement of most Wellington environmental groups and the Wellington District Maori Council. It appears that a start to cleaning up Wellington’s coast is imminent; joint treatment would reduce sewage bacterial levels by 99 percent and see a 95 percent reduction in sewage-contaminated water. The sewage pollution signs can then come down from 10 km of Wellington coastline and in a few years swimming and shellfish gathering will once again be possible. #