But the creation of an underground reservoir of treated water below Lake Tarpon would require several tests and take years to implement.
By RICHARD DANIELSON
Published June 30, 2003
EAST LAKE - Even before the weekend, June was more than twice as rainy as normal.
With so much rain, who thinks about the millions of gallons of water that spill over the dam at Lake Tarpon and flow to Tampa Bay?
Nobody needs that water now.
But in the dry season, it would be nice to have.
That's the idea behind a project being explored by the Pinellas County utilities department and the Southwest Florida Water Management District.
Last week, the water management district, also known as Swiftmud, approved spending about $29,000 to continue work on the possibility of taking water out of Lake Tarpon during the rainy season, treating it and pumping it underground for safekeeping. It could then be pumped out later and used to water people's lawns.
"The issue with our water supply is that we tend to get a lot of water all at one time, and then we don't get a lot of water for a long time," Swiftmud spokesman Michael Molligan said. "One of the keys is storage."
In the water business, the idea being pursued at Lake Tarpon is known as aquifer storage and recovery, or ASR. Think of it as creating a huge underground reservoir or storage tank.
In addition to Lake Tarpon, Pinellas officials are considering an aquifer storage project near the South Cross Bayou water reclamation facility on 54th Avenue N. But those plans aren't as far along as the Lake Tarpon project.
And city officials in Clearwater, Largo and St. Petersburg have all looked at similar projects. Largo officials are scheduled to vote this week on a reclaimed water expansion that could use up to 11 aquifer storage wells.
The creation of an underground reservoir below Lake Tarpon is still several years off. A test well must be drilled near the lake. Then officials will do a bunch of tests: How much water could be stored below ground? What treatment would work best? Would the stored lake water stay in one place? Would it be just as good when it came up as when it went down?
Just as important, local officials have to be reassured that the idea is safe.
"The jury's still out," Pinellas utilities director Pick Talley said last week. "They're going to have to show me."
County commissioners agreed last year to look into the underground storage project. If stored, the lake water would help conserve reclaimed water, wastewater that has been treated enough to be sprayed on people's yards. It would not be used as drinking water.
Commissioners were wary. Underground storage is used around the state, but it picked up a bad name two years ago when the Legislature wanted to relax the requirements for treating water before it was pumped underground. Protest killed that idea.
This is different, say water officials. The water taken from Lake Tarpon would be treated: filtered first, then disinfected with chlorine. Or maybe filtered and disinfected with ultraviolet light.
Either way, it would essentially be safe enough to drink by the time it was pumped underground, said Dave Slonena, hydrogeology manager for Pinellas County utilities.
Officials plan to ask the Florida Department of Environmental Protection for a permit to put a test well in John Chesnut Sr. Park. The well would go in a part of the park not used by the public.
That test well will be used to answer questions about how much water could be stored below ground, and whether it would stay put. Officials would store the water 235 to 335 feet below ground. That's 150 feet below the drinking water supply. There's also a layer of clayey limestone that separates the two, so they shouldn't mix.
Slonena said officials might try to pump up to a million gallons of lake water a day underground. If it worked, the underground storage might hold as much as 90-million gallons of water. By comparison, the county's sprawling William E. Dunn Water Reclamation Facility on Alt. U.S. 19 in Palm Harbor holds 55-million gallons of water.
The county estimates that the Lake Tarpon aquifer storage well might cost $1.8-million. Trying to find 90-million gallons of storage space on the ground would cost a lot more, Slonena said.
"This is going to be underground and, obviously, a lot less expensive," he said.
