Wastewater Planning Driven By Environmental Effects

Annual Conference

Southland District Council (SDC) operate twenty wastewater schemes throughout the District, each servicing between 30 and 2,500 people (totalling about 12,000 people). This large number of schemes spread over a large geographic area combined with a relatively low rating base poses challenges, particularly as existing resource consents expire and new legislation, such as the National Policy Statement for Freshwater Management (NPS-FM), requires improved freshwater quality.

To proactively address this, SDC embarked on a journey of developing a Wastewater Strategy (the Strategy) that would prioritise scheme upgrades on a District-wide perspective based on the overall adverse environmental effects in the wider catchment. In parallel, SDC, as part of the Southland Economic Project, worked with the other Southland territorial authorities to develop high-level upgrade scenarios for ‘representative’ wastewater schemes to meet a range of potential freshwater quality outcomes of the NPS-FM and Environment Southland’s response (ie limit setting process for freshwater catchments).

This paper outlines the two-staged approach SDC is using to develop the Strategy and outlines how the outputs from the Southland Economic Project underpin the approach to develop and cost wastewater treatment and disposal options for the District.

Stage 1 is now complete and pulls together information from a wide variety of sources. Uniquely it uses a ranking in the form of a traffic light system to identify potential issues for each scheme and summarises the results for all schemes on a single table. The categories considered include population change, feasibility of land disposal, existing consent compliance and ability to meet current and potential future receiving water quality standards. The categories and the ranking basis for each category are outlined in this paper.

This paper outlines the overall rankings for the twenty wastewater schemes resulting from the assessment in Stage 1. Six schemes are ranked ‘red’, ten are ranked ‘orange’, two are ‘green’ and two are ‘white’ (private treatment plant or newly constructed). This overall scheme ranking provides a scientific basis to inform decisions on which wastewater schemes to prioritise for upgrades to enable SDC to realise the greatest environmental benefit for a given expenditure. The paper then outlines the approach to be used in Stage 2 to develop wastewater treatment and disposal options for each overall ranking.

Stage 2 of the Strategy is in progress, however SDC is using outputs from Stage 1 and the Southland Economic Project to inform strategic planning, including the 30 year Infrastructure Strategy and the Long Term Plan. This paper describes how the outputs have been used as well as next steps.

Conference Papers

WASTEWATER PLANNING DRIVEN BY ENVIRONMENTAL EFFECTS.pdf

pdf
640 KB
26 Sep 2018

Thursday, Brooklyn 2, 11.30am.pdf

pdf
1 MB
01 Oct 2018