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A front loader moves dry soil so other heavy equipment can work in damp areas of the Sweetwater Wetlands as workers remove drainage pipes and brush on Wednesday. These wetlands are being rebuilt to remove mosquito habitat and create more open water to attract birds.
photos by a.e. araiza / Arizona Daily Star
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DID YOU KNOW
Sweetwater Wetlands was built as part of a quid pro quo between the city of Tucson and the Arizona Department of Environmental Quality. The city agreed to build the wetlands back in the mid-1990s in exchange for avoiding a $400,000 state fine for failing to have enough sites to monitor the bacteria content of then-newly-introduced Central Arizona Project water. The wetlands opened in March 1998, at a construction cost of $1.8 million.
Source: Bruce Prior, Tucson Water hydrologist
bird species
Birds in Sweetwater Wetlands include:
Northern shoveler — common or abundant, spring, fall and winter.
Green-winged teal — common, winter and spring.
American wigeon — common, spring and fall.
Orange-crowned warbler — common, spring, fall and winter.
Yellow warbler — common, spring, summer and fall.
Gila woodpecker — common, year-round.
Song sparrow — abundant, year-round.
Great blue heron — rare, but increasing, year-round.
Gray flycatcher — rare, year-round.
American goldfinch — rare, spring, fall and winter.
Sources: Tucson Water and Tucson Audubon Society.

Tucson Region

Sweetwater steps are for the birds

Wetlands improve dramatically after overhaul by Tucson Water
By Tony Davis
Arizona Daily Star
Tucson, Arizona | Published: 01.08.2009
An oval-shaped pond, ringed by deep green cattail and bulrush plants, is so shallow that one can almost see the plastic liner at the bottom of the Sweetwater Wetlands.
That pond has become a sign of dramatic improvements at the 18-acre artificial wetlands due to a sweeping overhaul by Tucson Water in the name of mosquito control.
The utility started work Wednesday on the second half of a two-year project to clear out marsh grasses that form prime mosquito habitat and clog ponds so densely that there's little room for birds. The entire project's cost is nearly $250,000.
The eastern wetlands are closed until the project is finished in April. Until then, visitors must park in a lot on the north side of Sweetwater Drive and west of the current lot. A temporary entrance has been created west of the normal entrance, which is closed.
The problem's history
When Tucson Water officials designed the wetlands to treat reclaimed water more than a decade ago, they created two major kinds of habitat. They dug shallow ponds that they knew would draw marsh grasses, and deeper ones to attract a wide array of ducks.
They wanted marsh grasses because they expected the reclaimed water sent to the wetlands from the neighboring Roger Road reclamation plant, across the street, would be very poor quality "backwash," the dirtiest material. They hoped the wetlands would clean out the gunk, Tucson Water hydrologist Bruce Prior explained Wednesday as he walked along the shallow pond.
But the bulrush and cattail proved to be good mosquito habitat. The reeds and marsh grasses are growing so thickly that keeping them under control has become a "maintenance nightmare," Prior said.
Also, the reclaimed water's quality has proved much better than expected in recent years, Prior said. So authorities don't need as much grassy area to treat the wastewater, which typically comes into the wetlands high in nitrate levels before it is cleaned and ultimately shipped to city parks and golf courses.
The nitrates act as fertilizer, nurturing the bulrushes.
The new project's payoff
Until last year's work started, the west side shallow ponds, with about 10 inches of water, were literally choking with grasses. Now, with a plastic liner at their base, the cattails and bulrush have crept up to the ponds' edges, but no closer.
"Mosquitoes don't like to lay eggs in open water. They love to fly into the plants and lay eggs," said Prior, manager of Tucson Water's mosquito-abatement program. "The way I look at this is that every time we remove vegetation, we remove mosquito habitat."
Another advantage is that city workers have stocked the ponds with mosquitofish to eat skeeters.
More birds, too
The wetlands have always been a local birding hotspot, drawing about 100 varieties, not counting rarities.
The shallow ponds now can draw wading birds such as great blue herons, great egrets and belted kingfishers that were rare in the past, said Prior and Tucson Audubon Society members.
"They're definitely improving things," said Darlene Smyth, Tucson Audubon's field trip coordinator. "Not only is there more open water in the west ponds, it is easier to see the birds that are there."
● Contact reporter Tony Davis at 806-7746 or tdavis@azstarnet.com
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