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Most of Friday's rain will miss aquifer

While rainfall from Gabrielle - up to 8 inches in some areas - will help fight the drought, about 80 percent will run off into rivers, Tampa Bay and the Gulf of Mexico.


© St. Petersburg Times, published September 15, 2001

While rainfall from Gabrielle -- up to 8 inches in some areas -- will help fight the drought, about 80 percent will run off into rivers, Tampa Bay and the Gulf of Mexico.

Tropical Storm Gabrielle dumped up to 8 inches of rain on some parts of the bay area, and sloshed over the Green Swamp, headwaters of four major rivers in west-central Florida.

Now the question becomes, did it do the job?

Does the wet storm mean we're finally done with drought conditions, and the aquifer is officially restored to optimum levels?

"It's doubtful that one storm is going to put us that high," said Michael Molligan, spokesman for the Southwest Florida Water Management District, the agency commonly called Swiftmud.

But Gabrielle is nonetheless helping restore the aquifer, the underground store of water that sustains the area's drinking water needs.

Molligan stressed that "any time we get rainfall it'll help." By midafternoon, nearly 8 inches of rain had fallen in Pinellas County and 5 to 6 inches had fallen in Hillsborough.

But it will take a while to assess just how much help the storm provided, because water can percolate down to the aquifer over a matter of weeks.

The latest data, released by Swiftmud on Wednesday, showed the aquifer was 0.23 feet above the low-normal level -- an improvement over the week before -- in a four-county district that includes Pinellas, Pasco and Hillsborough.

The same data showed the aquifer was 1.01 feet below the low-normal -- also better than the previous week -- in a six-county region that includes Hernando and Citrus counties.

That data was collected before Gabrielle came ashore on Friday. By the time new measurements are taken and released next week, the aquifer level presumably will be higher. "We would anticipate it improving, certainly, over the next couple of weeks," Molligan said.

"You'll see some quick improvements in rivers and then you'll see some lakes get some improvements," Molligan added. "But if the aquifer hasn't come up high enough to support those levels, they're going to be temporary."

But in October, the dry season begins. A few weeks of parched weather could dry up the extra water provided by Gabrielle.

"What we really need is to continue getting some rainfall into the dry season," Molligan said.

The problem with a storm like Gabrielle is that more than 80 percent of the rain will run off into Tampa Bay, the Gulf of Mexico and other places where it will not recharge the aquifer.

That's like pouring five cups of milk into a one-cup container -- most will spill out, so you can't use it.

"The most useful rainfall for the region is a sustained rain at a low rate," said Michelle Klase Robinson, spokeswoman for Tampa Bay Water. "What we're getting now is heavy rains and flash-flooding and a lot of runoff."

"Days like today really underscore our need for a reservoir so we can capture some of this rain and use it during dry times," she added.

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