ASSESSMENT OF ENVIRONMENTAL IMPACT OF SANDHILLS STORMWATER MANAGEMENT SYSTEM – PUBLIC EXHIBITION

The constructed wetland treatment system consists of three wetland cells or tiers. Local stormwater and seasonal groundwater flows are conveyed through the wetland cells. The wetland has been designed specifically to improve the quality of water flowing through the wetland it is discharged via the existing stormwater outlet to Clarkes Beach. The cells will have a standing or operating water level which is set by pipes which discharge water downstream from the cell when it raises above the standing water level. Each cell has a weir set at the extended detention level so that high flows can be safely conveyed through and across the wetland system. The macrophyte zones of the cells will be unlined, meaning that a portion of the stormwater that flows into the cells will infiltrate the soil. Deep zones have been included to provide refugia for aquatic plants and animals between rainfall events. The deep zones will be lined with an impermeable liner to better retain water between events.