Wetlands - Evatt (West Belconnen)

Evatt wetlands

25/03/2019 - Civil works nearing completion, macrophyte planting commenced.

15/2/2019 – Concrete structures nearing completion and soft landscaping commenced.

14/12/2018 - Civil works continue. Gross pollutant trap (GPT) installed and construction of the outlet structure is underway.

7/11/2018 – Earthworks are nearing completion.

7/8/2018 - Fences are now up around this site and construction will start soon.

21/6/2018 - Letters advising of the start of construction are being delivered to residents who live within a 100m radius of the site. Please check your letterbox. You can also view the letter here.

This project in West Belconnen is one of the biggest of the ACT Healthy Waterways sites. It includes two wetlands, a sediment pond, a vegetated swale and the rehabilitation of a degraded anabranch on two sites about 400m apart.

The wetlands on the southern site are being “retrofitted” into an established urban catchment, drawing water from the existing stormwater system. They will have a combined surface area of approximately 5,100 square metres.

The southern site also includes a gross pollutant trap (GPT), sediment pond and associated drying area, designed to dewater sediment before it is collected and taken off site. Rock armaments will protect the wetlands from periodic flooding.

The wetlands were carefully positioned to avoid experimental grassland plantings maintained and studied by the local catchment group.

Similarly, changes to the original plans for the northern site were prompted by community concerns over the potential loss of a patch of crab apples.

The current plans now include the extension of an existing swale (a depression that collects and carries stormwater) from 85 metres to 135 metres. It will meander through surrounding grassland, filtering water discharged from the pipe network before it flows into Ginninderra Creek.

The existing anabranch (a disconnected part of the creek) is congested with trees, undergrowth and sediment deposits which mean water only enters it during floods. The anabranch will be cleared and regraded to restore natural flows.

Together, the various water quality treatment components will remove over almost 17,000 kilograms of nitrogen, phosphorous and suspended sediment from urban stormwater before it enters Ginninderra Creek.

The project is one of three water quality infrastructure projects being built downstream of Lake Ginninderra. Another wetland on the corner of Ginninderra Drive and Copland Place and the revegetation of a stormwater drain in Florey complete the set.

Catchment West Belconnen
Start date June 2018
Likely construction finish date April 2019+
Anticipated establishment periodTwo years from the finish of construction^
Open for public useApril 2019*

+Construction may be delayed by a number of factors, including bad weather. Planting is part of the construction phase and the timing of the growing season may impact on construction timelines.

^Water plants in particular may take up to two years to become established. The length of time may vary depending on ground and weather conditions.

*Some areas of the site may remain closed to the public past this point to allow for additional planting or for plants to become established.

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 services, community feedback and maximise water quality benefits.

  • Armaments were added to protect the wetlands from localised flooding.
  • A drying area was added to dewater sediment removed from the GPT and sediment basin.
  • The small wetlands planned for the northern end of the site were replaced by a wide vegetated swale.

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.
  • The construction site will be fenced for public safety during the entire length of the project.
  • Detours for walkers and cyclists will be in place and will be clearly signposted.
  • 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.

Wetlands - Evatt - landscape plan