Drought in Florida -- much more than just water supply problem

Florida's big "sinkhole" -- in Winter Park, not far from Disney World -- has been blazoned over TV screens and newspaper front pages across America in recent days.

That huge depression which devoured a house, most of a municipal swimming pool, half a dozen vehicles, and portions of two streets in its 100-yard-wide and eight-story-deep maw is a dramatic and destructive phenomenon. But it is only evidence of far broader and even more serious problems in this fast-growing sun state: the drought Florida has been suffering this spring and the damage done to the state's underground water supply by decades of development.

While engineers try to determine how to stop the Winter Park sinkhole from eating away one of the town's major thoroughfares, other sinkholes are opening up throughout central Florida, and local governments and water management boards are trying to stop people from consuming so much water.

The last significant rainfall on peninsular Florida was in March, and as the drought has worsened, public and agricultural water supplies have been severely taxed. Much of central Florida's water comes from supplies that permeate limestone deposits under the state. During a drought, water is sucked out of the ground faster than it can be replaced, leaving empty, unsupported cavities. If these cavities are close to the surface, the weight of the overburden can cause the ground to collapse into sinkholes.

Sinkholes are not the only disasters caused by Florida's drought. In Bradenton on Florida's west coast, the water dipped so low in a reservoir behind a dam near the Gulf of Mexico that the pressure of the brackish water became greater than the pressure of the fresh water. That caused the salty water to be forced through cracks in the dam into the reservoir, and the freshwater supply was ruined.

Much fires continue to rage through the dry Everglades and other swamps and forests throughout the state, ruining thousands of acres and wildlife habitat and forcing the closing of some highways because of the smoke. Gov. Robert Graham has authorized use of National Guard troops to help fight the fires. The air throughout much of the state is filled with the acrid smell of burning vegetation.

Dry conditions are helping farmers with their spring harvests, but they could delay the next planting because the ground has become too dry. Citrus growers complain that the stress on their trees caused by the drought, coupled with damage caused by last winter's severe freeze, could substantially reduce next year's citrus crop.

Farmers and homeowners alike are looking for a break in the weather that will signal the beginning of the summer rainy season.But, in the meantime, water management officials around the state worked on mandatory water-use restrictions that would cut back consumption by 20 to 25 percent if a significant amount of rain did not fall this week.

In south Florida a 25 percent water use cutback is in effect, and the level of Lake Okeechobee has dropped so low that the water cutback may have to go to 50 percent by the end of the week.

Droughts are nothing new to Florida. Since 1960, the state has recorded below-normal rainfall most years. This has turned the state's water management districts from flood control to water regulation.

For decades in the state's early history, water was something to be eliminated. Draining swamps and channeling rivers to make farmland and protect against floods were lauded as ways to make Florida into something more than mosquito-infested wasteland, and now the peninsular part of the state is crisscrossed with drainage ditches.

But by draining away its water, the state has destroyed its wetlands that provide the delicate balance that allows rainfall to seep into the underground water supply. Now, instead of draining its wetlands, the state government is fighting to protect and buy the remaining swamps.

Throughout much of central Florida --where phosphate mining and agriculture use vast quantities of water -- hydrologists have noticed a constant decline in underground water levels during the past decade.And as the underground fresh water declines, salt water begins seeping in.

That makes the water supply problem most acute along the state's coasts where most of the massive population influx has settled. Pinellas County, a densely populated area that includes the cities of St. Petersburg and Clearwater on a peninsula on the state's west coast, has little fresh water of its own because the pure water under the county has been replaced by salt water.

Pinellas must get nearly all its water from rural counties east of it, but those counties are beginning to rebel. Water supplies should not be pumped to St. Petersburg and Tampa, the counties say, at the expense of the environment and growth in rural areas. A mandatory 20 percent cutback in water usage was imposed on southwest florida may 20.

Local governments and water management authorities re predict increased competition for water supplies as the state's population continues to soar. Plans to pump water to southwest Florida from the Suwannee River have drawn opposition even before they have been seriously proposed. Some hydrologists predict that water could be the limiting factor that c ould close the state's growth.