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Water authorities say Floridan Aquifer won't be hurt by three cities' plans to pump water

It is easy to understand why residents of Clearwater, Oldsmar and an unincorporated neighborhood near Tarpon Springs are worried that those three cities plan to pump millions of gallons of drinking water from new wells near their homes.

After all, the residents saw what happened in January in Hillsborough County: a major outbreak of damaging sinkholes after farmers pumped groundwater onto their fields to protect crops threatened by freezing temperatures.

Couldn't the same sinkhole outbreak occur here and put their homes at risk?

Regional water authorities say the two situations aren't comparable and the Pinellas well projects could not cause such a sinkhole outbreak. I pass along their reasons for those who fear damage to their homes and neighborhoods when Tarpon Springs, Oldsmar and Clearwater start pumping. First, a little history.

Tarpon Springs buys water from Pinellas County, which in turn buys it from Tampa Bay Water, a regional water wholesaler. But the price for that water has been rising. Tarpon Springs officials want more control over the price and supply, so the city is seeking permits to build its own water supply system. But when a well site was proposed on a residential lot outside the city limits, nearby residents who feared sinkholes went to the county for help. The County Commission turned down the city's request for a well there.

Oldsmar, which buys its water from the county and also is seeking water independence, will build a water plant and drill 12 wells to pump water from beneath the city. Several residents recently questioned the wisdom of the plan, since the limestone that underlies Florida can collapse if too much water is withdrawn too quickly.

Clearwater pumps about 30 percent of its own water and buys 70 percent from the county, but it wants to reverse those percentages in future years. The city plans to drill 13 new wells, mostly clustered in the Countryside area of north Clearwater. Some residents strenuously object.

The Southwest Florida Water Management District, also known as Swiftmud, is the government agency that oversees pumping of underground water in this part of Florida and issues or denies permits for wells. Swiftmud executive director David Moore explained why Hillsborough's experience with sinkholes is not relevant to North Pinellas.

For one thing, it is a matter of scale, he said. Both counties pull water from the Floridan Aquifer, a huge body of fresh water that is underground. When the farmers were trying to save their crops, they pumped nearly 1 billion gallons of water a day onto their fields. In a matter of days, they had drawn down the aquifer 60 feet, Moore said.

Compare those numbers with the plans in North Pinellas. Taken all together, the three cities plan to pump about 11 or 12 million gallons a day from wells. The expected aquifer drawdown is only 1 to 2 feet, Moore said.

Swiftmud assigns pumping limits to new wells. It sets those limits by determining how much water can be pumped from a well without creating sinkholes, drying up wetlands or nearby wells, or lowering water levels in lakes and rivers. A city that violates the pumping limits faces hefty fines. Swiftmud also requires regular monitoring around wells to watch for signs of adverse environmental impacts and can require that a well be shut down.

One might reasonably ask, if water authorities are so careful about pumping, how is it that Pinellas was able to drain so much drinking water out of Pasco County in past years that lakes and streams dried up?

Moore calls that a different era. Many of those well fields went into operation in the 1930s, '40s, '50s and '60s, when there was little understanding or concern about the potential for environmental damage, he said. These days, when it comes to building new well fields, the process "is very protective of the environment," he said. It is not unusual for Swiftmud to significantly reduce a community's gallonage request when it applies for well permits.

With so many communities and water suppliers already sucking water from the Floridan Aquifer, I asked Moore if it is really a good idea for the three cities to build new systems so reliant on the aquifer. Moore said the three cities actually will be tapping an underground source not used by Tampa Bay Water: a layer of brackish, or slightly salty, water.

Tampa Bay Water gets its water three ways: from rivers and streams, from desalinating very salty sea water, and from drilling deep into the Floridan where the water is fresh. The cities, on the other hand, will harvest a shallower layer that is brackish and will run the water through a reverse osmosis process to make it fresh.

When the three cities are no longer customers of Pinellas County, Tampa Bay Water will not have to supply as much water to the county and may be able to go a little longer without having to develop additional sources of water for its remaining customers. Tampa Bay Water's supply also may be a little less stressed during times of drought.

In the future, more residents than these may face well-drilling near their homes, because the Tampa Bay region's thirst for water is enormous and the "low-hanging fruit" — fresh water that is easy to obtain — already has been picked, according to Moore.

"We need to look under every rock," he said, "to see if there is a sustainable water supply there."

Diane Steinle's e-mail address is dsteinle@sptimes.com. To write a letter to the editor for possible publication, go to tampabay.com/letters.

Water authorities say Floridan Aquifer won't be hurt by three cities' plans to pump water 03/06/10 [Last modified: Friday, March 5, 2010 10:49pm]

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