Deal would allow water treatment plant and other projects to go forward if salamander is declared endangered.

With the odds increasing that Austin's Jollyville Plateau salamander will be added to the federal endangered species list, city officials are working on an unusual agreement aimed at ensuring that any new federal protections for the amphibian don't stall several large projects, including a controversial water treatment plant.

"The rumblings have been growing that the salamander could be added to the endangered list soon," said Nancy McClintock, an assistant director in the city's Watershed Protection and Development Review Department.

The city and the U.S. Fish and Wildlife Service are working on a trade-off, one the federal government hopes will be a blueprint for other communities.

The city would agree that, during construction projects, it would place even more emphasis on protecting the salamanders' habitat than the Endangered Species Act would require. In exchange, the federal government would impose no additional requirements on the projects if the salamander is finally declared endangered.

The terms will be worked out over the coming weeks and vetted publicly for perhaps a year, according to city and federal officials. The process will start Wednesday , when city officials hold a public hearing to explain how the agreement would work. City and federal officials said the agreement is not intended to influence whether the salamander is ultimately placed on the endangered list — an assertion questioned by some environmental activists.

The agreement would apply only to city projects and not private development. But federal officials said private property owners can also strike such a deal. Perhaps two dozen communities around the country have already struck similar deals, according to the city.

The 2-inch-long salamander lives in the Jollyville Plateau, an area in Travis and Williamson counties roughly bounded by the Colorado River, MoPac Boulevard (Loop 1), Lake Travis and U.S. 183. The animal lives in caves and springs, including the Bull Creek watershed and some of the most prized development areas in Travis County. The population of the salamanders is unknown, but the city is studying its numbers.

The salamander has been eligible for endangered status since December 2007, after groups such as the Save Our Springs Alliance argued that the threat of habitat destruction could jeopardize the species. The federal government determined that the salamander is probably worthy of protection. But the Fish and Wildlife Service also decided that a final decision would have to wait while it worked through a logjam of about 280 other species at greater risk.

But while the salamander remains on the government's to-do list, the SOS Alliance and other environmental activists are accusing the city of jeopardizing the salamander's habitat by building a $440 million water treatment plant near the shore of Lake Travis. To pipe the water into town, the city will have to drill tunnels beneath the fragile series of underground caves in the Bull Creek watershed.

The city is now boring 3-inch-wide holes in Bull Creek Park to determine the flow of water and the composition of the rock beneath the park, among other tests. Today, the City Council is scheduled to vote on $44 million worth of treatment plant contracts.

"It's no coincidence they're announcing this right as they're drilling in Bull Creek Park," said Bill Bunch , the executive director of the SOS Alliance. "It's all about the treatment plant. If they wanted to protect the salamander, they wouldn't be drilling, basically drilling blind, under those caves and threatening the spring flows."

Chuck Lesniak, the watershed protection department's environmental program manager, said Bunch's assessment gives too little credit to the city's precautions.

"We share the concerns, and that's why we've been looking at this for a long time," Lesniak said. "Is it zero risk? We can't ever say zero risk. But we've minimized the risk."

Lesniak said the city and the Fish and Wildlife Service have been talking about a salamander agreement for more than two years.

Normally, when a species makes the endangered list, a local government is required to work with the Fish and Wildlife Service to create a complicated "habitat protection plan." Federal officials have to agree that the plan would protect the species, for instance by limiting development or setting aside other land as wildlife habitat.

That is what happened with the Balcones Canyonlands Preserve. The massive preserve is west of Austin and was created because, by the late 1990s, federal protections of endangered birds threatened to stymie development in the area. The preserve essentially designated some areas for development and others for open space.

A Jollyville salamander plan could take months or years to complete, McClintock said.

"You could be building a fire station, building a library, doing vegetation restoration, and then you suddenly have to figure out how it would affect you," McClintock said of the salamander. "This agreement gives us a higher level of certainty."