Holder Wetlands is a series of three wetlands designed to treat incoming stormwater from the suburbs of Weston Creek, Holder, and Duffy before discharging into the Molonglo River. These three wetlands will contain over 2.4 million litres when full.
Stormwater pollution is a concern for all urban areas. It consists of visible pollution, such as litter and rubbish, and less seen pollution such as sediments, and nutrients including Nitrogen and Phosphorus. These unseen pollutants can cause algae blooms, disrupt natural ecological processes, and reduce water quality therefore reducing amenity for water users.
Stormwater is diverted from the existing stormwater infrastructure to be treated through one sediment bay and three treatment wetland ponds. Each year the wetlands will remove over 138,000 kilograms of nitrogen, phosphorous and suspended sediment from stormwater runoff before it flows into the Molonglo River.
Waterwatch testing by volunteers pre and post treatment has shown that the wetlands are working to reduce nutrients in the water. Explore this data here.