This component of the project involves converting part of the existing Isabella Pond to a wetland. The new wetlands will attract birds and other native wildlife and provide more opportunities for recreation. They will also be important in improving water quality downstream in Lake Tuggeranong, the Murrumbidgee River and the wider Murray-Darling Basin.
Isabella Weir is being upgraded to bring it into line with national best practice guidelines and the recently introduced ACT Dam Safety Code. The upgrade has included the widening of the Weir to increase its capacity to accommodate major floods.
Water levels inside Isabella Pond have been lowered in preparation for planned rectification works to be undertaken on the Isabella Weir walls. Works are expected to get underway this week (w/c 18 Feb) at which time Isabella Pond will be completely drained. The water levels in the downstream Tuggeranong Pond will also be reduced by approximately one metre to enable access to the downstream face of Isabella Weir. Major works as part of the upgrade were completed in late 2018 and the Weir was allowed to fill to identify any minor defects. Rectification works will take approximately one month to complete. Following these works, the Weir and Pond will be allowed to fill. The community may notice a slight reduction in water levels across the year for routine planting and landscape maintenance works.
Carp are an introduced freshwater fish and listed as a pest species. The Commonwealth Government has funded a National Carp Control Plan to undertake preliminary research and planning for the potential release of a biocontrol, the herpes virus, over the next two to three years. Carp in Upper Stranger Pond and Isabella Pond will be removed when the ponds are drained. Qualified ecologists will relocate any native fish and wildlife. Once the project is complete, the ponds will be restocked with native fish to restore a more natural environment in the pond. Removing carp from Isabella and Upper Stranger ponds will reduce the need to remove a large number of dead carp from these ponds if the biocontrol is released.
For more information about the ACT Healthy Waterways project visit www.act.gov.au/h2ok.