A Successful Long Term Strategy for Wastewater Infrastructure Planning and Consenting

South Wairarapa District Council (SWDC) is responsible for the operation of wastewater treatment and disposal facilities at Featherston, Martinborough, and Greytown. In 2008, replacement resource consents for all three urban facilities were required to enable their continuing operation. Currently each scheme comprises pond based treatment discharging treated wastewater to sensitive inland surface freshwater bodies.

There are increasing demands and pressures on small territorial local authorities in New Zealand to decrease the actual and potential effects of treated wastewater and disposal on the environment, commonly resulting in increasing financial pressure on small communities with associated ageing and declining population bases. SWDC has experienced these pressures and has responded to this challenge by developing a comprehensive long-term integrated strategy for wastewater management (“the Strategy”) in the District.

The Strategy is focused on the treatment of wastewater through land disposal, and removal of effluent from local rivers and streams in an affordable staged manner to optimise the reduction in adverse effects associated with direct discharges of treated effluent to water, particularly during low river and stream flow conditions where potential effects on water quality are greatest. The stages have been determined primarily on the basis of the SWDC funding approval processes and community affordability. The prioritised implementation of land application during low environmental flow conditions will form Stage 1 of the upgrades and is programmed to commence in the current Long Term Plan period 2015-2025. Following the completion of the Stage 2 upgrades (future Long Term Plan 2025-2035), there will be no wastewater discharged to surface water bodies below 3-times median flow, thereby avoiding the majority of effects which are currently being observed.

Following a comprehensive review of affordability across all Council services, SWDC identified a programme of expenditure of over $30M to give effect to the first 35 years of the Strategy. The implementation of the Strategy therefore relies upon a level of certainty which can best be provided by long term consents. As such, SWDC has sought the maximum term of 35 years for the replacement consents associated with each treatment plant. To support the applications for long term consents, a comprehensive suite of proposed consent conditions has been developed based on robust and proven technology and a commitment to future expenditure within the ability of SWDC to fund.

Resource consents with the maximum allowable term of thirty five years have recently been granted for both Greytown and Martinborough wastewater treatment plants. The consents require the development and approval of a suite of management plans (Inflow and Infiltration Reduction Management Plan; Tangata Whenua Values Management Plan; Odour Management Plan; Water Discharge Management Plan; Land Discharge Management Plan; and others) that will form the details by which the activities must operate. These management plans require suitably qualified independent review, input and review by an appointed Community Liaison Group, and Regulator certification prior to specific stages of the scheme being implemented. This process ensures a collaborative approach to consent implementation and review whilst providing SWDC, the community and the regulator with flexibility to manage uncertainty associated with long term consent timeframes. The implementation of an Environmental Monitoring Plan is also required to enable confirmation and ongoing assessment of actual effects. In addition, two key reporting milestones at the completion of Stage 1 and Stage 2 are required to prove the outcomes of the long term plan are being met.