Pond - Mawson (Yarralumla Creek catchment)

14/12/2018 – Macrophyte planting is complete.

8/8/2018 – Construction continues with the laying of the foundation for the gross pollutant trap (GPT).

9/8/2018 – Bird netting will be installed in August in preparation for spring planting.

16/10/2018 – Civil construction nearing completion. Site fences will soon be removed and macrophyte (water plants either in or around the wetland) planting will commence.


With four schools nearby, the new pond opposite Marist College on Athllon Drive could serve as a great location for an outdoor classroom. With this in mind, multiple rock ‘seats’ and benches will be included on the elevated viewing platform.

The pond will divert water from Yarralumla Creek and, in the long term, help improve the quality of water flowing into the Molonglo River. It will also attract a variety of wildlife including water birds.

The finished pond will have a treatment area of 4666m2 and, when full, contain approximately 6 million litres of water (about the same as three Olympic swimming pools).

Careful design has ensured that the size of the pond and the sediment basin is proportionate to the amount of available water during low-flow periods, making it as efficient and cost-effective as possible.

A number of existing trees will be retained, mostly eucalyptus and casuarina. Some trees will be removed, mostly Populus alba, a declared weed species.

The pond will also have a natural viewing platform with seating close to the existing bike path.

Catchment Yarralumla Creek
Start date March 2018
Construction finishedOctober 2018
Anticipated establishment periodTwo years from open date*
Open for public useNovember 2018

+Construction may be delayed by a number of factors, including bad weather.
^The establishment period may change depending on ground and weather conditions. During the establishment period, flows into and through the asset will be managed to suit the conditions and to protect and nurture the plants.
*Some areas of the site may remain closed to allow for plants to establish.

Design changes

Although water quality is the priority for ACT Healthy Waterways, the project team is also working to a fixed budget and timeframe.

During the final design phase, some changes were made to the original concept designs to accommodate underground services, community feedback and maximising water quality benefits.

  • The total pond area was reduced by 14% to accommodate the surface grade, achieve a better cut/fill balance and avoid disturbing the nearby fibre optic cable.
  • The stormwater diversion pit was moved away from Mawson Drive, 100m closer to the pond which resulted in significant cost savings.
  • A review concluded that harvesting and reusing stormwater would not provide good value for money at this stage. However, outlet works have been configured to accommodate future harvesting infrastructure.
  • The alignment and position of the maintenance access point was changed to reduce the impact on an existing stand of trees.

More information

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How this project might impact you

  • Trucks will pass in and out of the area during the improvement work. Routes have been established to minimise traffic disruption and noise.
  • Detours for walkers and cyclists will be in place and will be clearly signposted.
  • The construction site will be fenced for public safety during the entire length of the project.
  • The contractor has prepared a Construction Environment Management Plan (CEMP) to detail how it will deal with flora and fauna issues.

Landscape design plan

Click on the image to enlarge.

Landscape design for the pond at Athllon Drive, Mawson