Rain garden - Karabar (Upper Molonglo)

Rain garden between Alanbar Street and Kenneth Place, Karabar

A new rain garden is being constructed between Alanbar Street and Kenneth Place in Karabar. Construction will be completed by the end of June 2019.

With a total treatable area of 950 square metres, it will filter and clean water diverted from nearby pipes before returning it to the stormwater system.

Approximately 52,000 kilograms of suspended sediment, nitrogen and phosphorous will be removed every year from stormwater bound for the Queanbeyan River.

Part of the ACT Healthy Waterways infrastructure project, the rain garden is the only site located outside the ACT.

It is positioned within an existing overland flow path which diverts and moves water during major storm events. For this reason, the design ensures that flood capacity of the space is not reduced.

ACT Healthy Waterways identified this site as a priority early in the project as it is upstream of the Molonglo River, Jerrabomberra Wetlands and Lake Burley Griffin.

An existing cycle path has been relocated to the east.

Water plants in particular may take up to two years to establish. The length of time may vary 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 the public past this point to allow for additional planting or for plants to become established.

Design changes

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

  • Kenneth Place rain garden removed due to insufficient area and clashes with underground services. Replaced with stormceptor underground treatment unit.
  • Shape of southern rain garden adjusted to suit detailed survey.
  • Above ground sediment bays deleted due to proximity to public, additional capacity built into underground pollutant trap instead.
  • Adjustments made to driveways and service vehicle access arrangements to improve safety.
  • Diversion pipe removed from Lily Place/Kenneth Place alleyway due to change to underground treatment in Kenneth Place.

More information

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