There are 1.765 million farm dams in Australia, occupying 4,678km2 and storing 10,990 gigalitres of water, 20 times that in Sydney Harbour.
On the farm we studied, however, there are just two dams. Sheep love to cool their hooves in the unfenced dam. Their faeces causes a biological process called eutrophication — the abundance of nitrogen and phosphorus in the faeces encourages dense blooms of noxious algae, decreasing water quality and starving all other life in the dam of sunlight and oxygen.
The second dam was fenced a decade ago. Native freshwater mussels, an important food source for the First Nation Gadubanud peoples, were introduced to the dam, filtering up to 50 litres of water per day each. The dam now supports fish, frogs, snakes, birds, myriad grasses, banksia, bees. Healthy surface algaes reduce evaporation. Cleaner water makes for healthier livestock and more effective irrigation. Banksia flowers and honey provide supplementary income streams for the farm.
This is a trophic cascade — a tiny change that propogates and multiplies through food chains, causing an abrupt but persistent shift in the functioning of an ecosystem.
If the introduction of a thoughtfully placed fence can cause a trophic cascade in a dam ecosystem, what could a building do?
This Bachelor of Architecture studio was designed by Frank Burridge and taught at Monash University in 2022.
Map of surface water