Wetlands - Holder (Lower Molonglo catchment)

Aerial photograph of Holder wetlands

Wetland, between Dixon Drive and Cotter Road, Holder

The popular Centenary Trail now weaves its way through new wetlands at Holder.

The finished wetland covers 5,600m2 and, when full, contains approximately 2.4 million litres of water (about the  same as an Olympic swimming pool).

Water will be diverted from existing stormwater pipes in the area to the wetlands before flowing into Weston Creek and the Molonglo River.

Each year the wetlands remove over 138,000 kilograms of nitrogen, phosphorous and suspended sediment from stormwater runoff before it flows into the Molonglo River.

A two year macrophytes (water quality plants) establishment period has commenced.   Establishment period refers to the process by which a plant becomes established in a new habitat.

Design changes

During the final design phase, a number of changes were made to the original concept designs to accommodate community feedback, make best use of the existing terrain, reduce project costs and maximise water quality outcomes.

  • Detailed survey of  the terrain and the local stormwater system meant the wetland was resized—including reducing the number of sediment ponds from three to one—to match the inflow  and to avoid unnecessary excavation.
  • Two open drains were  diverted to the main sediment pond. A third drain will be reshaped and revegetated to allow in-line water treatment.
  • The final design includes a new gross pollutant trap and two new trash racks to capture litter and other large pollutants.

More information

Find out what you can do on your own block to improve water quality in our lakes and waterways.

Learn more about how a wetland works.

Landscape design plan

Wetlands landscape design plan