Sewage solution escalates to $35m

Designation and resource consents have been granted for a $35 million community sewerage system at Mangawhai.
Recent Northland Regional Council approval for more than a dozen water, land-use, coastal and discharge permits is expected to get work started soon on the long-awaited Mangawhai EcoCare project. The scheme was first mooted by the Kaipara District Council about eight years ago and was tipped to cost only $13.5 million as recently as 2002.
But the contractor the council was then dealing with went broke in 2004 and costs started increasing as new contractor Earth Tech Engineering Pty Ltd came on board and the scope of the scheme changed.
Kaipara Mayor Peter King said the council purchase of a $5 million dairy farm adjacent to Brown Rd in the Hakaru River catchment for disposal of EcoCare effluent had been a significant extra cost.
The council had been very fortunate to obtain the farm, which would help make the scheme one of the best in the North, he said.
Mr King expected construction to start with the building a wastewater treatment plant on a 5000sq m site in Mangawhai Park on the corner of Thelma Rd and Molesworth Dr.
The proposed EcoCare project comprises 21km of sewer, 18km of property drains, 15 pumping stations and 6km of rising mains. It is designed to deal with a normally resident Mangawhai population of 3000 and a peak of 8200 people.
The proposal also incorporates a new 110,000cu. m treated effluent storage dam and a new irrigation system to apply treated effluent to pasture on the dairy farm.
One of the key concerns raised by many submitters on the proposal was the potential for discharges of wastewater runoff to contaminate the Hakaru River. A two-member Northland Regional Council hearings committee, chaired by Cr Lorraine Hill, refused an application to discharge wastewater directly to the river because its members were not satisfied such an activity - with the potential adverse downstream effects - was sustainable.
Mangawhai at present relies on septic tanks and small communal systems for wastewater treatment, many of which are adversely affecting the local and adjoining coastal environment.
Actual and potential effects of the proposed EcoCare plant were all assessed by the NRC hearings committee, including the construction process and ongoing potential odour, noise, visual and traffic movement effects once the plant was operating.
All of these effects were considered to be either of a temporary nature, limited in area and mitigated through adoption of best-practice techniques during construction or would be sustainably managed through appropriate consent conditions once the plant was operating.
Any party not satisfied with the decision has until April 17 to file an appeal with the Environment Court.