The City of Whitehorse lies within the Melbourne Water catchment zone. The waterways of Gardiners, Dandenong and Koonung Creeks are significant environmental, landscape and recreation locations and form part of an advanced open space network that is highly valued by the community. These waterways are all tributaries of the Yarra River subject to occasional flash floods in intense downpours.
Gardiners Creek rises in the centre of the City of Whitehorse and flows through Blackburn, being fed by a number of drains and channels in Blackburn North, Blackburn South and Forest Hill. The creek then flows southwest, exiting the Municipality through Burwood into the City of Monash at Ashwood.
Dandenong Creek rises in the foothills of the Dandenong Ranges in the Shire of the Yarra Ranges, flowing through the City of Whitehorse before forming the south-eastern boundary of the City of Whitehorse at the Winton Wetland on the northern side of Boronia Rd. Dandenong Creek flows south at this point, passing under the Burwood Hwy at Vermont South and flows into the City of Monash.
Koonung Creek rises in Nunawading and forms the northern boundary of the majority of the City of Whitehorse. The creek flows west, straddling the northern boundary of Box Hill North and leaving the Municipality at its north-western tip before joining up with the Yarra River in the City of Manningham.
Most of the City of Whitehorse is fully developed and is now undergoing a phase of redevelopment, with increases in population density and intensification of land use, particularly along the main transport routes. As a result, the potential for increased flood risk and potential danger has increased and needs to be managed in a proactive manner. The key flood risks are likely to be associated with relatively short and intense rainfall events of a few hours’ duration, but extended long-term rainfall over several days will also create risks and social disruption.
The Bureau of Meteorology is responsible for providing a flood and storm warning service for heavy rainfall in Victoria in cooperation with other government, water and emergency management agencies. For metropolitan Melbourne, Melbourne Water owns and operates the flood warning system and provides warnings for the Bureau to disseminate.
The City of Whitehorse Flood and Storm Plan is developed by the City of Whitehorse Municipal Emergency Management Planning Committee led by Victorian State Emergency Service.