What is it all about?
Hurstville City Council constructed a bioretention system and landscaping works to upgrade Webbs Dam. Council undertook these works with funding support from the NSW Environmental Trust under the Lower Georges River Sustainability Initiative, the NSW Government's Waste and Sustainability Incentive Payment Program, and the Sydney Metropolitan Catchment Management Authority’s Botany Bay Water Quality Improvement Program.
During 2011, Council worked closely with the local community and the Lugarno Progress Association to develop a Landscape Masterplan that will guide the staged upgrade of the dam.
These works represent Stage 1 of the plan.
When was it completed?
Stage 1 of the Webbs Dam Upgrade was officially unveiled on the 16th of March 2013.
In order for the works to take place, the dam will be drained in accordance with a dewatering plan that has been prepared by Council’s consultant team. As part of this process, some of the native animals living in the dam (e.g. turtles and eels) were relocated elsewhere.
Once this was completed, a bioretention system was constructed in the eastern section of the dam. This filters and treats stormwater flows into the dam, which in time will be used to irrigate the adjoining sports fields. In the meantime, the improved water quality will help reduce the incidence of algal blooms within the dam and maintain the quality of remnant bushland downstream of the site.
Landscaping works along the southern edge of the dam were also done to improve public safety within the vicinity of the picnic area and barbeques.
What does it look like?
A plan of the Stage 1 works is shown on the back of the flyer. Key elements include the reshaping of the southern edge of the dam, the construction of the bioretention system, sandstone inlet and overflow structures, and the planting of more than 8000 native plants. Go and visit the site to have a look!
How will the bioretention system work?
Water flows into the system via the existing stormwater pipes and sandstone forebays, trapping sediment and gross pollutants such as plastic bottles and aluminium cans. The water then drains through the bioretention system, which includes layers of sand and other media to remove finer sediment and nutrients like nitrogen and phosphorus. The nutrients will then be used by the plants and small trees throughout the system.
Water will not pool more than approximately 20cm within the basin and will drain away rapidly. During larger storm events, water will overflow from the basin into the adjoining dam.
Download a copy of the project flyer
View a presentation made to the Lugarno Progress Association that includes more information about the project
Find out more about the Lower Georges River Sustainability Initiative (LGRSI)
Find out more about the Botany Bay Water Quality Improvement Program