Criticism by neighbors in area of tunnel is added to planned lawsuits.

A decade ago, Joe Wheeler gave up plans to open a corner store on a small patch of land he owned at the foot of the Hill Country.

The idea was impossible, he and neighbors say: Austin environmental regulations, intended to protect the area's underground springs and a nearby nature preserve, effectively precluded building on the property. Wheeler sold the eight-tenths of an acre to the city, which zoned it as parkland.

Wheeler now wonders how the city could decide to dig a 40-foot-wide , 100-foot-deep shaft on the property, at Spicewood Springs Road and Old Lampasas Trail, and then use it as a staging point to excavate an eight-mile underground tunnel to serve a planned water treatment plant near Lake Travis.

"I think it's a betrayal," Wheeler said.

City officials say such objections are understandable but are an unfair characterization of an essential public works project.

But opposition to the project is gaining traction in the lightly wooded hills of Spicewood Springs and is part of a renewed effort to halt a city plan to build a $550 million water treatment plant.

In addition to a grass-roots movement dubbed Stop the Shafts, to move the city's proposed tunneling route, two nascent legal challenges seek to derail the treatment plant. Those lawsuits claim the city cannot build the pipeline without endangering an environmentally fragile area of western Travis County.

The long-running debate over whether to build the plant, which would be Austin's third in operation, seemed to end last October when the City Council voted 4-3 to spend $3.1 million to begin clearing the site for preliminary work. Since then, the city has spent tens of millions of dollars on engineering work, equipment purchases and preparing the site, near RM 2222 and RM 620.

Neither the lawsuits nor the recent neighborhood objections appear to have altered the city's plans. Construction of the treatment plant and pipeline is still scheduled to start in fall 2011.

City officials, unconvinced by environmental activists' arguments that the city can conserve enough water to make the plant unnecessary, say any delays could expose Austin to water shortages as early as 2014 . They say the lawsuits are baseless. And, they say, all required environmental evaluations will be finished by the time construction begins.

"There is potential for environmental impacts with these shafts," said Chuck Lesniak , a manager in the city's watershed protection department. "But we're going to be very careful and make sure that doesn't happen."

The city plans to dig a shaft deeper than the area's underground springs, which feed nearby Bull Creek. Then crews at the bottom of that hole would drill sideways, creating a tunnel 30 to 40 feet wide. The excavated rock and dirt would be trucked away, and a crane would lower sections of 7-foot-wide pipe into the tunnel.

The tunnel would be eight miles long, connecting an intake on Lake Travis, the treatment plant and a reservoir at McNeil Drive and U.S 183 . The tunnel would run under the Balcones nature preserve, which is crisscrossed by underground springs.

But, Lesniak said, "If you get below the groundwater, (the tunnel) is unlikely to have any impact."

Critics say the construction is likely to harm the area's animals and the springs that feed Bull Creek.

The Save Our Springs Alliance and Environment Texas filed a lawsuit last month demanding that the city stop all work on the treatment plant until it finishes environmental studies. The lawsuit, filed in federal court, alleges that the project violates the Endangered Species Act by putting the Jollyville salamander at risk.

Lesniak said the lawsuit is baseless because the salamander is not listed as endangered, so it is not covered under the law.

"We will protect the salamander," Lesniak said. "But we don't need to halt the project."

A second lawsuit, being prepared by the Sierra Club's Austin chapter and the SOS Alliance, is more complicated and potentially far-reaching.

That lawsuit claims the city, county and federal government have failed to adequately protect some endangered species in areas of western Travis County as required by a landmark agreement struck in the early 1990s .

The agreement provided a blueprint for development in western Travis County, where the Endangered Species Act had stymied construction.

To ease simmering tensions at the time, federal, county and city officials committed to protecting the area's endangered birds and insects by creating the Balcones Canyonlands preserve. As part of the agreement, the federal government allowed more development than environmental protection laws would otherwise allow.

SOS and the Austin Sierra Club contend that city and county officials are violating that agreement primarily by not setting aside adequate land for the preserve.

They also say plans to tunnel under the nature preserve violate the agreement. One aim of the lawsuit: to force federal and county officials to oppose the treatment plant or jeopardize the agreement that makes development possible in areas west of MoPac Boulevard (Loop 1).

"They don't know what they're going to run into under the preserve. They don't know how far down those caves go," said Roy Waley , vice chairman of the Austin Sierra Club. "But if they run into a problem after spending hundreds of millions on the plant, are they really going to stop?"

The lawsuit has not been filed yet because such lawsuits require preliminary notices, which the environment groups have filed. The city has not formally responded.

But Assistant City Manager Rudy Garza said both lawsuits were expected and are just the latest in a line of objections that have been hashed out during more than 30 years of fights over the plant.

"It always seems to be something else," he said.

Garza said the concerns in Spicewood Springs are understandable — "No one wants a major disruption in their neighborhood" — but that disruptions are sometimes necessary.

The general route of the tunnel is probably set, but the city is considering some changes, such as pulling the excavated rock and dirt out of the tunnel from a shaft near the reservoir at 183 and McNeil, Garza said. That would mean far less truck traffic, noise and debris storage at the Spicewood Springs site.

Still, Garza said the Spicewood Springs property is the best excavation site for technical reasons, if it ultimately meets the city's environmental criteria.

The city has agreed, should that option be chosen, to truck out excavated dirt and rock only between 9 a.m. and 3 p.m. during the workweek to lessen the nuisance.

But if that is the case, the city cannot drill around the clock as planned because too much rock, dirt and water would accumulate at the site between haulings, creating a risk to the nearby creeks. The city would probably need months or years more to finish drilling, Garza said.

And, residents note, Bull Creek Ranch , a cluster of 33 townhomes, sits just across a two-lane road from the Spicewood Springs site.

"They seem to have made up their mind without doing all their homework and are just flying by the seat of their pants," said Eric Deal , president of the nearby Mountain Neighborhood Association. "There are a lot of things they haven't considered."

Spicewood Springs resident Desmond D'Souza has been circulating a report concluding that an alternative route could actually cost less than the planned one, which city estimates put at $103 million .

The alternative route runs along Pedernales Electric Cooperative land parallel to RM 620, a few hundred feet from that road, then follows Anderson Mill Road and then U.S. 183.

It would also avoid environmentally sensitive areas, said D'Souza, a computer software engineer, and run behind a series of businesses, which commercial real estate broker Jill Rowe said should give it weight over a route near homes.

"We don't have all the answers," said Warren Johnson, a retired civil engineer living in the Spicewood Springs neighborhood. "But this is worth further investigation. If our route works, that eliminates our problem."

City officials say roads are typically preferred routes for water mains, but not in this case.

Garza said the city looked at a similar route to the one proposed by D'Souza, which would have put the lines next to 620. But the city concluded that boring a tunnel under that route would cost roughly $40 million more. Digging a trench along that route, as opposed to a tunnel, while much less expensive, would reduce the road to one lane for long stretches.

Garza said a tunnel along D'Souza's suggested route would come with similar costs and said the businesses along 620 would be inconvenienced if the co-op allowed the city to dig a trench on its property. The city's engineers said that route was probably not feasible.

"To me, that ($40 million difference) is very compelling," Mayor Lee Leffingwell wrote in an Aug. 9 e-mail to Spicewood Springs resident Fred Manley, "and I find it difficult to reconcile that expense — both as a rate payer myself, and as an elected official."