In 2017 the ACT Government as part of its Healthy Waterways initiative undertook the draining of two urban ponds in Canberra.  The draining was required for a replacement and upgrade of a weir and to facilitate the construction of water quality control infrastructure.  The National Carp Control Plan (NCCP) requires understanding of total biomass of carp and the relation to regular monitoring to allow development of biomass and epidemiological models and planning for clean-up. The draining of these ponds was an opportunity to accurately quantify carp biomass and gain an insight into these values to existing monitoring of other ACT water bodies and assist other NCCP research.

Prior to the draining, monitoring was undertaken following standard electrofishing protocols.  Removal of the Carp and other fish in the ponds was done manually over three days for each pond as they were approaching empty. Subsamples of Carp were measured for length and weighed with a total of 5 tonnes of Carp were removed across two ponds.

Pond refilling is being followed by restocking with native fish and additional habitat enhancement in both ponds with significant drops in turbidity already observed in the first pond to refill.