Extreme droughts will come again, said Randy Worden, district manager of the Central Oklahoma Conservation District or COMCD.

And when drought comes, the three member cities of the COMCD -- Norman, Midwest City and Del City -- need to have more water resources at hand, he said. COMCD manages Lake Thunderbird primarily to provide raw water to the three municipalities, along with flood control and recreational activities like fishing and sailing.

Worden and environmental consultants from Tetra Tech spoke at a public meeting Tuesday at the Lake Thunderbird Boat House to launch an environmental assessment or EA exploring the effects of bringing additional water to the lake from southeastern Oklahoma.

"We are long overdue for an extended drought," Worden said.

The Lake Thunderbird Critical Need Water Supply Project would seek an agreement with the City of Oklahoma City to purchase augmentation water and draw that water from the Atoka pipeline which conveys water from Lake Atoka in southeastern Oklahoma to Lake Stanley Draper in southeast Oklahoma City.

Lake Thunderbird is a federally owned water storage facility holding 21,600 acre feet or 7 billion gallons a year, and was built in 1965. It falls under the jurisdiction of the U.S. Department of the Interior, Bureau of Reclamation. And because it's federally owned, an environmental assessment is required to be in compliance with the National Environmental Policy Act.

The proposal would augment Thunderbird's water with 4,600 acre feet during drought periods. An acre foot is is the amount of water needed to cover an acre, one foot deep in water, or 312,851 gallons. The extra water could potentially be transferred when the lake is down to 1,036 feet above sea level, although that is not a firm number, Worden said.

Lake officials' most recent drought scare was in 2006.

The levels at Lake Thunderbird dropped to 59.75 percent of the conservation pool and a level of about 1,030 feet on March 30, 2006, the lowest level in about three decades and leaving wide expanses of exposed red-dirt shore lines. It was a situation that COMCD board member Steven Jones said at the time could require emergency action if it continued. But a strong downpour the next day brought the conservation pool back up to 71 percent, raising the elevation 2.3 feet to 1,033.45 feet above sea level.

"That prompted us to find additional water if that were to happen again," Worden said.

The Atoka pipeline skirts the edges of Lake Thunderbird's tributary Hog Creek en route to its destination of Draper Lake. And there are three options being explored.

One would use a short buried pipeline connection from the Atoka pipeline to an existing valve near Franklin Road to a discharge point in the existing Willow Branch Creek.

Another option would involve constructing a buried pipeline along right-of-way on Franklin Road from the same connection point to the Atoka pipeline and a discharge point in Lake Thunderbird.

A third option would be a buried pipeline at the north end of the lake. It would involve constructing a short buried pipeline connection from the Atoka pipeline west of the intersection of Bethel Road and 144th Avenue NE to a discharge point in Lake Thunderbird.

The environmental assessment will consider resources areas including climate, air resources, water resources, biological resources, socioeconomics, cultural resources, public health and safety, hazardous and toxic substances, transportation, utilities, land use, recreation and aesthetics.

Tuesday's meeting was the scoping meeting part of the environmental assessment.

Attendees had several questions.

Judith Wilkens asked about how habitat around the lake would be affected.

David Broadfoot, senior environmental planner and scientist from Tetra Tech, said it would be part of the study of biological resources.

"Everything that's green and not green," Broadfoot said.

Norman Mayor Cindy Rosenthal asked if the water quality coming in would affect the algae in the lake.

"I know the general water quality coming in would be better," Rosenthal said.

"We don't have that answer," Broadfoot said, but said they would be studying that question.

Norman City Manager Steve Lewis asked how much each option would cost.

"We're not there yet," Worden said.

"That would be the next step," said Srini Sundaramoorthy, project manager with Tetra Tech.

Worden said concerns that they would start filling the lake with the extra water and then there would be a large rainfall would not cause problems.

"We can't fill it up overnight," Worden said of Lake Thunderbird.

Norman resident Mark Zahourek asked about the City of Norman's recent consideration of selling water to Goldsby.

"What (cities) do with the water is their business," Worden said.

But Norman Utilities Director Ken Komiske said councilmembers were not in favor of the Goldsby water sale.

Keith Thomas asked about invasive species arriving in Lake Thunderbird via the water transfer, specifically the zebra mussel.

Worden said although the zebra mussel was not at Lake Thunderbird, it was present in Lake Texoma.

"The greatest potential ... is taking boats from one place to another," Worden said.

He said Baxter and Jean Vieux of Vieux and Associates would also be involved in the assessment.

"This EA study is just one part of the puzzle," he said. "In order to import water, we have to get federal authorization."

The scoping period looking for public comments will continue through Sept. 30. Comments may be made to Worden at COMCD by phone at 329-5228; by fax at 321-6944; or by e-mail at rworden@comcd.net.

The draft EA is planned to be available about Dec. 1. The final EA is expected to be available Jan. 31, 2010. Those wanting to be notified when the draft or final EAs are available can contact COMCD.