Groundwater recharge is necessary in areas with peat soils to maintain underlying aquifer water levels and geotechnical stability. Dewatered peat soils are subject to shrinking and ground surface settlement.
The requirement for groundwater recharge is to be considered and specific design and council approval is required for any development in an area where peat soils can be anticipated. In particular, there is a significant area of peat and soils with high organic content in the Papakura area. Refer to Auckland Council technical report TR2013/040 (Stormwater Disposal via Soakage in the Auckland Region) for design guidance for all soakage systems. TR2013/040 also defines the likely extent of peat soils within the legacy Papakura District. However, the presence or absence of peat shall be confirmed by geotechnical investigation. Refer to the Proposed Auckland Unitary Plan (PAUP) and operative district plans for other requirements regarding groundwater recharge in peat areas.