Stormwater Discharge by Soakage in the Auckland Region

Soakage of stormwater is part of the natural water cycle that feeds groundwater and stream flows. In some parts of Auckland, soakage systems have been used for many years as a means of easily and cheaply disposing of stormwater close to source. Some of these systems have been ignored and poorly maintained leading to a gradual build-up of sediment and a reduction in performance over time. Areas suitable for soakage have not always been well defined and soakage has been attempted in areas outside suitable geology.

Auckland Council has released “Stormwater Disposal by Soakage in the Auckland Region” (Technical Report 2013:040). This contributes to Council’s new Code of Practice for Land Development and Subdivision which provides a consistent set of standards for the design and construction for stormwater infrastructure across the region.

The use of soakage can contribute to water sensitive design and has advantages such as; allowing a discharge to occur close to its origin, avoiding the need for a pipe network, reducing flow to any downstream network and providing groundwater recharge.