BROOKSVILLE — Farmers in Hillsborough and Polk counties pumped nearly 1 billion gallons of water a day out of the aquifer during the 11-day cold snap this month, causing 85 reported sinkholes in the region and about 700 complaints of dried-up or damaged residential wells, according to figures released Tuesday by the Southwest Florida Water Management District.
That 1 billion gallon figure is 16 times the normal average permitted quantity of 60 million gallons a day that the farmers can use. It's 10 times the combined 103 million gallons a day that St. Petersburg and Tampa residents use. It's enough water to fill up more than 15,000 Olympic swimming pools.
As a result, the agency commonly known as Swiftmud will convene a series of three workshops to consider how to avoid similar problems before next winter, executive director Dave Moore said. The first will be Feb. 15 in Plant City.
Among the proposals they could consider: require farmers to try other ways of protecting their crops, such as spraying foam over the plants, covering them with fabric or recycling the water after it's used for irrigation.
When the temperature dips to 34 degrees — 2 degrees above freezing — farmers began pumping water from underground and spraying it on their strawberries, blueberries and citrus. The aquifer produces water that's about 70 degrees, and as it freezes, the water releases heat that protects the crops from cold damage.
But to keep the crops warm, the farmers keep pumping millions of gallons from the aquifer and spraying it around until the weather gets warmer. Their permits say they can spray for 24 hours straight, then lay off for seven hours, then spray for 17 more hours.
This month's 11-day freeze was the longest stretch with temperatures below 34 degrees, according to records that date back to 1931. As a result, it marked the longest stretch of continuous irrigation to combat the cold, according to figures reported to the agency's governing board Tuesday. Moore repeatedly used the word "unprecedented" to describe the conditions.
The extensive pumping caused a drop of 60 feet in the aquifer in the Dover area. Within days of the weather warming up, the water level had gone back up by 50 feet. That triggered a series of sinkholes in the region.
"When we go below 30 feet, that's when we start seeing problems," Moore said.
Of the 85 sinkholes reported, 24 involved damage to the area's roads, deputy executive director Richard Owen told the agency's board. One affected an elementary school. Another swallowed a mobile home.
Rep. Richard "Rich" Glorioso, R-Plant City, told the board that five homes in his district had been condemned because of sinkholes, and Plant City officials must find $2 million to pay for sinkhole damage to city property. He contended that some farmers left their sprinklers on far longer than they needed to and that their excess water use contributed to the disaster.
"It is an emergency for east Hillsborough County, and they need help," he said.
Trapnell Elementary remains closed this week as engineers probe the underground void to figure out what to do about it.
The three alternatives to pumping billions of gallons of water all carry their own negatives, according to Swiftmud and agriculture experts.
Foam, for instance, costs $80 an acre to apply, blows away in a stiff wind and melts if the temperature gets above 45 degrees, requiring farmers to reapply if the temperature drops again. Putting down fabric covering requires a lot of labor, which can be expensive with a large farm. And recycling the irrigation water may raise food safety concerns if it's sprayed on the berries.
Of the dried-up wells, 115 complaints resulted from a single landowner's freeze-related pumping, Owen said. The property owner, identified in Swiftmud records as C. Dennis Carlton, had recently received a permit to pump a lot more water during such freezes than before, Owen said.
"We pumped a lot of water, no doubt about it, trying to save our crops," said Carlton, who is not a berry grower but leases his land to growers.
While he does not believe his tenants' pumping really affected 115 wells, Carlton said it's clear that Swiftmud needs a new system for dealing with freeze conditions. Currently, Swiftmud requires farmers whose irrigation damages neighboring wells that were permitted before their own to pay for fixing them.
"Typically during a freeze, you'd get six or seven" wells that were dried up or damaged, Carlton said. "You'd handle it and take care of it." Being told you have to fix more than 100 is startling.
Board member Hugh Gramling — who has served as executive director of the Tampa Bay Wholesale Growers since 1996 — warned that if Swiftmud were to force strawberry farmers to fix 10 or more damaged wells, it could bankrupt some of them.
Still, of the 700 well complaints that have poured into Swiftmud, about half the wells came back on their own, Owen said. But 60 were still not operating as of Sunday. Six had to be replaced by new wells, and 138 needed major repairs.
To speed up repairs, the board approved Owen's recommendation that Swiftmud put $250,000 into an emergency fund to help people damaged by this month's freeze. Moore would have the power to declare an emergency and use the money to fix private wells.
Craig Pittman can be reached at (727) 893-8530 or firstname.lastname@example.org.