The Strategic Planning Approach of the Central Auckland Stormwater Initiative

The Central Auckland Stormwater Initiative (CASI) is a regionally-significant programme initiated by Auckland Council to deliver improved stormwater services in the problematic and strategically-important central area of Auckland. Sub-catchments include the western part of the Auckland Isthmus, including the Central Business District (CBD) and covers an area from St Heliers in the east to the Whau Estuary in the west. CASI subcatchments generally discharge stormwater into the southern part of Waitemata Harbour.

CASI used a strategic planning process to identify conceptual solutions across a number of stormwater sub-catchments that previously had proven difficult to resolve due to a variety of complexities. Taking a top-down rather than a detailed approach has proved successful in setting the high level budget requirements and identifying a set of practical solutions, the most promising of which continue to be refined.

Potential benefits of integrating Auckland Council stormwater initiatives with Watercare’s wastewater initiatives include identification of an optimised solution which represents the overall Best Practicable Option for both stormwater and wastewater. The provision of stormwater solutions in these catchments may provide additional opportunities and benefits to be delivered by close co-ordination with Watercares proposed Central Interceptor. This will enable the best community outcome for the management of stormwater contaminants and the reduction of combined sewer overflows to receiving environments at less overall cost.