2012 December – Reclaimed water revives wetlands


Egrets and Heron

Egrets and Heron

Modern humans were drawn to the Phoenix area by these very rivers and by fertile soil, and soon began managing the water resources.  They built dams, diversions and canals to enable wide-ranging agricultural practices, to harness floods and to store water for times of drought.  All three of the rivers feeding the oasis at the confluence dried up.  No more did water flow between the banks of the Salt, the Gila or the Agua Fria Rivers.  The former oasis was plowed and put to work raising cotton, and the water required arrived via cement-lined canals.

A mushrooming population mandated the construction of a waste treatment center that was built at 91st Avenue, just upstream from the rivers’ confluence.  Currently the treatment plant takes in about 160 million gallons of waste water from five Valley municipalities daily.  The grey water produced is not potable, but is extremely valuable to desert cities.  About half of the reclaimed water is piped to the massive Palo Verde Nuclear reactor for cooling.  Some is sold to golf courses, city parks and industry. The water that’s left is pumped into the constructed wetlands called Tres Rios.

Here, 450 acres of wetlands flourishes as a complete natural system.  And the wildlife has come.  More than 150 species of birds have been sighted at Tres Rios, and mammals including muskrats, skunks, bobcats, beavers and raccoons hunt and breed in the area.  Migratory and wintering species of birds feed on fish, insects and plants, while toads, lizards and snakes find their place in the rich food chain.  Overflow from Tres Rios trickles into the Gila riverbed, resurrecting the riparian habitat in that stretch of the parched river.

A similar project called Sweetwater has been constructed in Tucson.  Reclaimed water is pumped into wetlands where green plants provide further purification before it infiltrates into underground aquifers through recharge basins.  When the city faces shortages, wells draw on this potable water source.  The town of Gilbert recharges ground water at Gilbert Water Ranch using wetlands that enable a vibrant riparian habitat.  None of these are pristine natural environments, but wildlife needs water, and humans are finding that solutions to some of our problems were invented long ago by Nature herself.

Photos were taken by Karen David.


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