A proposed reservoir south of Charlotte would help the region survive droughts, but environmental advocates say it appears to also be part of an undisclosed plan to expand water sales from the Catawba River.

Officials of the Catawba River Water Supply Project, owned by Union County and a Lancaster County, S.C., water district, insist they have no approval, money or immediate need to expand its water-treatment capacity.

The $27 million reservoir would only store water for use during dry spells, they say, as it has been described in applications for state and federal permits. The reservoir has been endorsed by Duke Energy, which manages the Catawba, and municipal water utilities in the basin.

But a 2008 engineering contract says the reservoir is the first of two projects. The second stage, it says, would expand the treatment plant from its 36 million-gallon-a-day capacity to 54 million gallons.

A new pump station that is part of the reservoir project will be able to pump 100 million gallons a day, the maximum the project is permitted to draw from the Catawba, according to a project presentation. Charlotte-Mecklenburg Utilities, by comparison, pumps 121 million gallons a day.

Use of the Catawba, which crosses the South Carolina line in southwest Mecklenburg County, is an increasingly sensitive topic. As droughts parched the region and growing communities demanded more water, the Carolinas faced off before the U.S. Supreme Court in a water-rights case settled about a year ago.

Union County, which the Catawba River Water Supply Project serves, was one of the nation's fastest-growing counties before the recession. Most of the county is not in the Catawba basin.

At a meeting Friday of a two-state Catawba advisory commission, environmental advocates said water conservation measures could end the need for a new reservoir.

The Southern Environmental Law Center, representing the advocacy groups American Rivers and the Catawba Riverkeeper Foundation, says the project could also connect to neighboring water systems.

The law center calls the project "a precedent-setting, unnecessary expenditure of public and ratepayer funds" that will encourage other water systems in the Catawba basin to create their own reservoirs rather than find alternatives.

Preserving their options

After a public records request, the center found emails in which local officials discuss dodging questions about whether they plan to expand the treatment plant after building the reservoir.

"Union County can't be in a position six months from now of having to move forward with an expansion and defending a statement from today saying 'we have no expansion planned,' " the county public works director wrote in June.

Project officials, however, say they have no immediate plans to expand. The project now treats no more than 22 million gallons a day of its 36-million-gallon capacity, director Michael Bailes said.

"Obviously, yeah, we've been looking at growth, but it's on the back burner and that's not an issue," he said. "Is it in the long-range plans? Yes."

The immediate concerns, Bailes said, are new restrictions on how much water Duke Energy would release down the Catawba during a severe drought. The 92-acre reservoir is intended to store water for use in such an event.

Duke official Mark Oakley agreed, saying the reservoir would help ease pressure to release water from upstream reservoirs during droughts.

Ecological concerns

Even relatively small reservoirs do environmental damage. The Lancaster County reservoir, about 20 miles south of Charlotte, will affect wetlands and two streams.

The U.S. Army Corps of Engineers, which is considering a permit for the reservoir, focuses on ways to avoid environmental harm in evaluating such projects. The environmental groups have asked the Corps to demand an analysis of alternatives to building the reservoir.

The Environmental Protection Agency has also written the Corps, expressing "significant concerns" with the reservoir.

Apart from environmental damage, the EPA says it hasn't received full information about water-conservation measures enacted by the Lancaster-Union project. Project officials say they're making progress on conservation.

Even in a worst-case drought scenario, EPA said, the project could get by with an additional 135 million gallons of stored water. The new reservoir would hold 900 million gallons.

"These measures should be exhausted before an additional reservoir is considered," EPA wrote the Corps.