A project designed to help save an endangered Delta fish has some people worried that it may damage their community and the Delta.

Known as the Two-Gates Fish Protection Demonstration, the project would install two gates along Delta channels between Bethel Island and Discovery Bay to see whether they prevent Delta smelt from dying in pumps near the Tracy area. Some East Contra Costa County residents argue that the plan would threaten the health of the Delta, water quality and recreational boating.

The U.S. Department of Interior's Bureau of Reclamation plans a five-year study on the gates' effectiveness in protecting the fish from pumps that deliver water from the Delta to Central and Southern California. It's hoped that the project would allow more water to flow south without killing the fish.

Officials from the bureau have recently gone to cities throughout the state to hear public comments about the plan. They stopped this week in Discovery Bay, where nearly 600 people came to discuss potential effects on the town.

Some complain that boaters would need to take longer routes to get to and from Discovery Bay when the gates are closed, and that pumping more water from the Delta would increase the salinity of the town's water.

Resident Chris Steele said he couldn't support the project as currently planned, and that the town needed more time to review the studies by the Reclamation Bureau. He thinks the primary goal of the plan is

"It's really frustrating," Steele said. "There are other techniques to save these fish, and they haven't looked at any of them."

Many are asking for an additional 90 days from the end of the public comment period on Nov. 17 for further investigation of the plan, Steele said.

"We want to get some scientists involved to check the study done by the (Bureau of Reclamation)," he said.

Pete Lucero, public affairs officer for Bureau of Reclamation, said he did not know whether the project's potential effects on Discovery Bay were studied, but the bureau "looked at the Delta in full, and looked at the area around the gates."

The gates would open and close at certain times, and people would be notified when they were closed, Lucero said.

The Two-Gates plan is projected to cost $80 million: $49 million for the construction of the gates and $31 for maintenance, operation and scientific analysis, Lucero said. The target date for construction to begin is the middle of next summer, but several permits and a funding source are needed, he added.

Lucero said proponents of the plan include the Metropolitan Water District of Southern California and the San Luis Delta-Mendota Water Authority — a group of water agencies from western San Joaquin Valley, San Benito and Santa Clara counties.

A number of local water districts also are involved, including the Contra Costa Water District, Lucero said.

Five scientists assembled by the CalFed Science Program to conduct an independent review concluded "the project goals should be clarified and made explicit."

Lucero said the project's goal is specific.

"This project, for us, is a fish-protection project," he said. "I think it's clearly stated "... that that's what we are trying to accomplish here."

He didn't dispute, however, that delivering water was an additional responsibility for the bureau.

"Our mission is to deliver water and power in an environmentally responsible way," Lucero said. "Water does travel through the Delta to the pumps. Our responsibility is to get water to the Central Valley."

Discovery Bay resident Jerry Creech also opposes the plan. "The problem is, there isn't enough water to supply Southern California and (have the Delta) still remain as it is today," he said.

Jonathan Lockett covers Oakley. Reach him at 925-779-7174. Follow him on Twitter at www.twitter.com/jonathanlockett.