The ACT Government is improving Canberra's urban waterways with the development of a number of urban wetlands. Newly built water bodies include:
These wetlands provide a range of benefits such as:
Wetland working bees tend to be scheduled in the warmer months of the year. At this stage there are no events planned.
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 was collected for the Eco-pond at Norgrove Park over 2008-2011 indicating how successful wetlands can be. Results showed that the pond and wetlands reduced:
The eco-pond also trapped:
Units at the Kingston Foreshore overlook Norgrove Park. Note the dense reed beds in the middle ground.
Image: Edwina Robinson
Shallow water zones, planted with local macrophytes (reeds) filter nutrients from the water at Norgrove Park.
Image: Edwina Robinson
Sullivans Creek once consisted of ponds, floodplains and rocky incised gullies. While the catchment restoration does not aim to mimic this historical form it does provide enhanced urban biodiversity by creating a series of planted ponds linked by fingers of vegetation.
Dragonfly. Image: Mark Jekabsons
Wood ducks. Image: Mark Jekabsons
Plovers. Image: Mark Jekabsons
While you might be lucky enough to spot a tortoise or a pied cormorant at your local wetland, chances are Gambusia holbrooki or Mosquito Fish will be present in vast numbers. These small fish - they only grow to 6cm - were introduced from America. Like many stories of introducing species from foreign places, Gambusia breed crazily fast and suffer little predation. They eat native fish, macroinvertebrates and tadpole larvae. Gambusia were introduced because it was thought they did a good job controlling mosquitos.
Research has shown that well designed wetlands without stagnant pockets of water and with good native fauna do a better job for keeping mosquitos in check. If you have a mosquito problem at your place – go round and throw out all the stagnant water that forms in plant saucers and non-circulating water features.
So what can we do about Gambusia?
The ACT Environment and Sustainable Development Directorate and the ACT Education and Training Directorate have produced a 56 page coloured booklet on constructed and natural wetlands. Units of work are provided for early childhood, later childhood, early adolescence and later adolescence. They focus on three essential learning achievements:
ELA 2 - The student understands and applies the inquiry process
ELA 19 - The student understands and applies scientific knowledge
ELA 20 - The students acts for an environmentally sustainable future
These units build understanding of what a wetland is and the place of wetlands in larger systems. They explore the practice of managing urban stormwater by constructing urban wetlands.
In order to understand that the Canberra region hosts a diverse array of wetlands, information is provided on sites such as the Jerrabomberra Wetlands, Ginini Flats, Nursery Swamp, Horse Park and Lake George. A case study focuses on the David St, O'Connor urban wetland, constructed in 2001.
Discovering wetlands in Australia (suitable for Years 3 - 6)