The significance of dams in regulating water flows has been highlighted by two recent developments – events that are taking place almost the world apart.
Suburbs of Sydney, Australia’s commercial if not administrative capital, are being protected from flooding by the Warragamba Dam following high rainfall across Sydney's water supply catchments. Completed in 1960 as a water supply project, Warragamba Dam supplies water to more than 3.7 million people living in greater Sydney. About 70 km west of Sydney, Warragamba, supplies some 80% of the Sydney region's drinking water.
However, Warragamba is currently spilling water after reaching 100% capacity, and nearby Avon Dam, Nepean Dam and Tallowa Dam are also spilling.
And while low-lying agricultural areas may anticipate some flooding as a result of the discharge, local authorities reportedly do not anticipate that any homes will suffer as a result.
At the same time as flood waters worry Sydney, in California residents and businesses are facing an all but unprecedented four-year drought.
However, despite continued hot conditions, Californians surpassed June’s conservation rate and reduced water use by 31.3% during July, exceeding the 25% conservation mandate recently imposed in a bid to address the crisis.
For June and July, the cumulative state-wide savings was 29.5%.
“This isn’t your mother’s drought or your grandmother’s drought, this is the drought of the century,” said Felicia Marcus, Chair of the State Water Resources Control Board, adding: “Millions of conscientious Californians are the real heroes here — each stepping up to help local water resources last longer in the face of an historic drought with no certain end date.”
While it may be argued that these events are at either end of the water supply scale, these two developments are nonetheless evidently of considerable concern to the homeowners and residents affected. Perhaps more significantly though, is to consider the potential impacts of these natural events in the absence of the dams and civil structures that manage water flows right around the world.