Storm water management and improvement Case of Freemans Bay Auckland.

Gregory Shahane De Costa, Mathew Bradbury

Friday 3 july 2015

12:36 - 12:39h at Oceania (level 0)

Themes: (T) Managing deltas, (ST) Wetland protection and shore restoration, Poster pitches

Parallel session: Poster pitches: 15K. Deltas - Wetland

Freemans Bay is a vast and recovered industrial zone, encompassed by a petrol chemical storage facility and a tank farm. Major storm water outfall from the surrounding Freemans Bay catchment can cause contamination in the ground around the tank farm and the sea. The entire Freemans Bay catchment anticipated 244hactares, 72.7% of impervious surfaces (178hactares). The impervious surfaces are divided into 64hactares of building roofs and roads, 114hactares of driveways and footpaths. The remaining 27.3% or 66hactares of the catchment are pervious surfaces (parks, lawns and vegetated buffers which have been found to be the source of large amounts of storm water flowing through Wynyard Quarter at the bottom of the catchment), where storm water can penetrate through the ground layers as a filter for initial treatment before reaching the storm water network for discharge. However, most of the storm water is assembled and discharged via a four meter by three meter drainage pipe below Wynyard Quarter This study focuses on storm water issues identified within the Freemans Bay area. The purpose of the study is to find solutions to help manage land contamination, sea pollution and improve the storm water system within the area. A thorough investigation occurred throughout the entire catchment with the aid of Auckland GIS viewer. The findings include a design of a wetland storm water treatment system to treat the storm water produce by the 2 year storm event within the area before discharge, reduce the speed of run-off to prevent erosion and also to increase the aesthetic and recreational nature of the area.