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Climate change threatens Florida's drinking water supply

If climatologists are right, Florida's future could be a thirsty one: Climate change, blamed for eating away at Florida's coastline, is also quietly encroaching on the state's drinking water.

Much of the damage to Florida's water supply will take place out of sight, in the underground aquifers that provide most of the state's drinking water. As rising seas nibble at the state's coastline, saltwater intrusion will also creep steadily inland.

"We used to assume that we could use the past records to predict the future," said Mark Stewart, a professor at the University of South Florida. "Now, we just don't know."

To cope with uncertain freshwater supplies, the state has turned to expensive reservoirs and energy-intensive desalination plants, and plans to build even more. Florida could turn to schemes that seem unthinkable today, like pumping wastewater into aquifers that supply our drinking water.

"Recently, there has been rising agreement among water managers that this is an issue that needs to be addressed," said Chris Milly, a research hydrologist with the U.S. Geological Survey. "Climate change is real, and affects the water system enough that it will have an impact on the decisions they make on how they deliver water to their customers."

• • •

Florida's climate has already begun to change. Sea levels have started to rise. Saltwater fish are swimming farther upstream, while saltwater mangroves invade freshwater marshes. Rainfall has become less predictable. Rivers and reservoirs are at near-historic lows.

Climate models offer little guidance, Stewart said. Some predict more rainfall, others predict the state will devolve into a desert. Despite the uncertainty, there are worrying challenges ahead, he explained.

"It's like the federal deficit," Stewart said. "The good news is it will happen really slowly, over decades. The bad news is our kids will pay for it."

The International Panel on Climate Change predicts that as the climate warms, oceans will expand, pushing sea levels up by nine to 23 inches by the end of the century. The estimate doesn't include glacial melting. Some scientists predict that seas will rise three to five feet in that time. At little more than three feet, the sea will cover Florida Keys and the Everglades, and soak coastal parts of cities like Tampa and St. Petersburg, according to a recent report by Florida Atlantic University.

The damage underground could move faster and cause more devastation. Saltwater intrusion could extend 50 percent farther inland than the above-ground impact, said Motomu Ibaraki, an associate professor of earth sciences at Ohio State University and author of a recent study on how rising sea levels could damage underground aquifers. A state like Florida, which heavily pumps its groundwater, could see even faster intrusion, he said. As sea levels rise and saltwater moves inland, underground freshwater supplies will become brackish and undrinkable.

The scientific uncertainty often gets subsumed into the political battle between those who believe climate change is a natural cycle and those who believe that it's man-made. With a lack of clear answers about what direction climate change will take, it's hard to muster the political will to curb greenhouse gas emissions by dramatically altering the way we consume energy, Stewart said.

"The public has a hard time dealing with scientific uncertainty," Stewart said. "They want a yes or a no."

• • •

As underground water supplies erode, Florida will increasingly look to rainfall to supply enough freshwater for a growing population. The region's increasingly volatile rainfall patterns, with wild swings year-to-year, complicate efforts to plan ahead.

"It makes a big difference in how you plan, because you have to be prepared," said Paula Dye, chief environmental planner for Tampa Bay Water. "With climate change, will these swings become more pronounced? Or is this already climate change we're seeing? Or is 30 years of data too little to tell?"

Dye remains confident that Tampa Bay Water will weather any changes. The utility, which serves 2.5-million people and delivers 186-million gallons a day, has 13 well fields far enough inland to be safe from rising seas. It also draws water from the Hillsborough and Alafia Rivers and the Tampa Bypass canal.

"Our facilities are already built so that over a 50-year period, you would adapt and can adapt," Dye said.

To slake Florida's growing thirst amid these challenges, the state will have to spend millions of dollars on infrastructure like reservoirs, desalination plants and reclaimed water systems.

The 3-year-old C.W. Bill Young Reservoir cost $146-million. Tampa Bay Water last month sued the builders of the reservoir because of deep cracks that have formed in the walls. The cracks forced Tampa Bay Water to keep water levels at less than half of its 15-billion-gallon capacity, sharply reducing available water during an ongoing drought.

Tampa Bay Water's recently completed desalination plant cost $158-million and was plagued with missed deadlines and bankrupted builders before it was finally completed years late and millions of dollars over budget.

Investments like these increase the price of water for homeowners and businesses.

"It will be more expensive," said Ken Herd, water supply program manager for the Southwest Florida Water Management District. "What we're seeing is that the availability of fresh groundwater is minimal. … The low-hanging fruit on the water supply tree — groundwater — has already been picked."

• • •

The scarcity of freshwater could rekindle the state's notorious water wars.

Florida, Alabama and Georgia have fought for more than 17 years over the water flowing in the Apalachicola, Chattahoochee and Flint rivers. Urban Atlanta, which has failed to conserve water or build any reservoirs, uses the water flowing out of Lake Lanier into the river system to supply its sprawling growth. The ongoing battle, intensified by a crippling drought across the Southeast in 2007 and part of 2008, has pitted Atlanta's burgeoning $5-billion economy against Florida's $200-million seafood industry.

Smaller squabbles have flared up throughout the state, setting the battle lines of the future.

Environmentalists have balked at parts of the Everglades restoration, which some call a thinly veiled attempt to make sure South Florida has enough freshwater to drink. Activists around the Suwannee River have raised concerns about Progress Energy's plans to use the river to cool a new natural gas power plant.

Tampa Electric and Mosaic Fertilizer have been hunting for water after the city of Tampa backed away from plans for a $188-million pipeline that would have funneled the city's reclaimed water to the companies' Polk County plants.

Utilities and water managers are now studying the possibility of pumping wastewater underground to recharge the aquifer along the Hillsborough coast. In recent months, even the controversial idea of a north-to-south water pipeline enjoyed a short-lived revival.

Many of these decisions will likely be made without knowing how exactly the state's climate will change. Researchers are working on climate models for Florida, but for now most climate models lack the data that planners and politicians need to plan ahead.

"We know we're in a new place," Milly said. "But we don't have road map for where we are. Or we have a very imperfect one."

Times researcher John Martin contributed to this report. Asjylyn Loder can be reached at aloder@sptimes.com or (813) 225-3117.

Climate change threatens Florida's drinking water supply 11/08/08 [Last modified: Monday, November 10, 2008 3:06pm]

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