Health of rivers hinges on unproven technology

Reducing huge water flows from Lake Okeechobee to the Caloosahatchee and St. Lucie estuaries depends almost entirely on finding places other than the lake to store water.

Faced with burgeoning land costs and limited space, scientists are looking 1,000 feet below the earth's surface in search of that storage.

A yearly average of 584 billion gallons of water a year is flushed from the lake to the rivers because more than 100 years of drainage projects have virtually eliminated South Florida's natural ability to retain water in marshes and lakes.

Everglades restoration projects intend to put the storage back into the ecosystem, but a large part of that storage depends on using a technology called Aquifer Storage and Recovery on an unprecedented scale.

With Aquifer Storage and Recovery technology, fresh water is injected deep into the earth and stored there until drought conditions require its recovery.

The largest ASR project in the nation is in Las Vegas, where 30 wells have the capacity to store about 100 million gallons of water a day. The Everglades project depends on 333 wells that will have the capacity to store up to 1.6 billion gallons of water a day.

No other place in the world has used ASR to store and reuse so much water.

While scientists are confident the technology will work, they're not so confident it will work as well as Everglades restoration planners predicted.

That's why the U.S. Army Corps of Engineers and the South Florida Water Management District are coming up with a contingency plan.

Peter Kwiatkowski, director of resource evaluation and subregional modeling for the water management district, said he is "reasonably confident" the technology will work for Everglades restoration.

Several ASR wells are working now in Florida and water samples from locations where future wells are being considered look promising, Kwiatkowski said. He said it appears the water in some places will require less treatment than anticipated.

Kwiatkowski's confidence is tempered, however, by the enormous scope of the project. About $100 million will be spent on studies and pilot projects to evaluate the technology. The makeup of the water that already exists under the earth, the type of subterranean rocks present and fissures in the rocks could all have different effects on ASR's feasibility.

"The way the project is designed is to let the data speak for itself," Kwiatowski said.

While scientists collect data, another team of scientists will be conducting studies to find out how the Comprehensive Everglades Restoration Plan will pan out without ASR or without as much ASR.

"It's really more of a modeling, a 'what if?' investigation while the pilot studies are going on," said Liz Manners, project manager and biologist with the Army Corps. Once new models are complete, scientists will run several scenarios to evaluate how restoration would work without ASR technology and to study alternative storage options. The plan is slated for completion within 18 months.

John Morgan, lead ecosystem restoration representative for the district, said the restoration plan was never intended to be cast in stone and that the new technology has had its fair share of controversy from the beginning. Whether it can be permitted on such a massive scale in Florida and whether recovering the water will be cost-effective is still unknown.

"It depends on the right geology and the right conditions. We still have a lot to learn about the ground deep beneath the surface here in Florida, and that's why we are doing the pilot studies," Morgan said.

If ASR doesn't work as well as hoped, other water storage and water supply options could include desalinization, recycling wastewater for reuse, keeping Lake Okeechobee a foot higher or building more reservoirs and flowways.

Keeping the lake higher would be controversial because high water damages the Herbert Hoover Dike, destroys marshes and habitat within the lake and increases the need to flush water from the lake to the estuaries in the rainy season.

Building more reservoirs and flowways could be more expensive because of the cost associated with buying land.

Another unknown is the actual cost of the ASR technology and whether Congress will appropriate the money to help pay for it. Building the wells may not be as expensive as building reservoirs due to savings on land acquisition, but maintenance could be much more pricey. As energy costs rise, the cost to operate to ASR well pumps will also increase.

"Everything we're trying to do here in saving the Everglades also has to be measured by the economics of it," Morgan said.

© 2006 marconews.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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