The City of Greater Geelong required controls be put in place to manage infrequent flooding of a housing area upstream of Lake Victoria.
Alluvium Consulting initiated the design concept and involved AWMA through the early stages of development. The partnership determined that a unique passive gate, operating on the basis of differential buoyancy forces, could be used in place of a traditional electro-mechanical gate solution. This saved considerable capital expenditure as well as providing a virtually maintenance free “set and forget” solution.
As the concept involved a gate design without local precedent, AWMA built and tested a to-scale prototype model. After successful prototype testing, AWMA proceeded with detailed design, manufacture, and dry factory commissioning to ensure the gates would perform as intended, in the field. Two 4m wide x 1.5m high LayFlat gate leaves were manufactured from marine grade aluminum and protected with sacrificial anodes to ensure a long design life in salt water conditions. The gate leaves were then hinged to automatically open (horizontal) or close (vertical) in response to upstream or downstream water levels, based on a combination of in-built buoyancy and self-weight. AWMA installed and wet commissioned the gates which included full functional testing, where the gates operated exactly as intended.The gates rise automatically when the downstream (saline) water levels rise above the crest of the weir, isolating the rising salt water. When upstream levels increase, the door opens allowing fresh water flows to pass into the lake.The gates are self-regulating and effectively maintenance free. They have an instantaneous response time, a guaranteed failsafe opening and no opportunity of failure from operator or equipment.
The result is a simple, low capital, low whole of life solution to a complex issue.
For more information
Client: Alluvium Consulting
Asset Owner: City of Greater Geelong (COGG)