Improving Stormwater Quality

Using wetlands in urban areas is one of the most environmentally effective ways to improve the quality of stormwater. One of the most common causes of poor water quality is suspended solids. Wetlands slow the flow of water (as opposed to fast flowing concrete channels) allowing solids to settle. Wetland plants and sediment bind phosphorus and nitrogen removing these contaminants before the water is discharged.

Water quality data collected for the Eco-pond at Norgrove Park over 2008-2011 indicates how successful wetlands can be. Results showed that the pond and wetlands reduced:

• Total Phosphorous by 77% (ACT Water Sensitive Urban Design Targets for a redevelopment site are 45%)
• Total Nitrogen by 62% (ACT Water Sensitive Urban Design Targets for a redevelopment site are 40%)

The eco-pond also trapped:

• 66% of Suspended Solids (ACT Water Sensitive Urban Design Targets for a redevelopment site are 60%)

Units at the Kingston Foreshore overlook Norgrove Park. Note the dense reed beds in the middle ground.

Shallow water zones, planted with local macrophytes (reeds) filter nutrients from the water at Norgrove Park.