Depletion of the Floridan Aquifer in Southwest Florida

Depletion of the Floridan Aquifer in Southwest Florida

The Floridan Aquifer in Southwest Florida is the source of potable water, irrigation for citrus and other agricultural products, as well as the source of a multitude of springs and rivers that provide essential habitats and recreational opportunities. This aquifer is also utilized by large phosphate mining operations. Long-term aquifer declines began when the southwest portion of Florida began to be developed. The result of the aquifer declines was a reduction of flows in the Peace River, the lowering of lake levels in the Lake Wales Ridge area, springs ceased to flow, and saltwater intrusion accelerated. Management of this resource became critical as drought conditions further complicated a dire situation. From the crisis, the Southwest Florida Water Management District developed the Southern Water Use Caution Area (SWUCA) and the SWUCA Recovery Plan. Only time will tell if the recovery plan can restore the Florida Aquifer.

In 1975, the center of the aquifer level declines was in an area dominated by phosphate mining. The mining operations then began to practice conservation measures that drastically reduced their dependence on the Floridan Aquifer (SWFWMD, 2006). At the same time that demands on the aquifer were being reduced by the phosphate industry, an increase in demand was being felt due to large scale agricultural endeavors. In addition to the irrigation needed to sustain crops during the dry season in Florida, large quantities of water are often pumped in the winter months as freeze protection when the temperatures dip too low. With the agricultural demands, the center of the declines just shifted to the agricultural areas.

In the 1970s, St. Petersburg and Pinellas County was experiencing an explosion in population but they had no more potable water to provide to its residents. The county began buying up land in Pasco and Hernando Counties to the north and started developing wellfields. When water that was withdrawn from the aquifer in this area, it resulted in drawing down wetlands and cypress swamps across the two counties. Trees fell over, private wells went dry, and lakes and ponds shrunk. The Water Wars were on as citizens began to sue Pinellas County and the Southwest Florida Water Management District (SWFWMD) (Dedekorkut, 2003).

By the early 1990s, more residents were being impacted by the groundwater withdrawals as sinkholes began to open up in the northern parts of the SWFWMD. Water officials tried to assure residents that the sinkholes, dry wells, and shrunken lakes were the result of the drought. When rains returned to average (and above average), the officials shifted the blame to development, and then to agriculture (Glennon, 2002). It is not always an easy task to prove the connection between water being pumped from underground and the devastating effects that were being seen at the surface. By 1996, a SWFWMD study concluded that not only was there a connection, but it was a “significant” connection.

Prior to this epiphany, water officials devised a plan to effectively mask the effects of the groundwater pumping. Where lakes had gone dry, officials were still contending that it as the drought that was to blame, so they decided to pump groundwater to augment the lakes. Much of the water drained back into the aquifer and more was lost to evaporation, but for a short time, the illusion that there were no problems was achieved.

The next step in the water crisis was to decide what to do about all of the groundwater withdrawals. If the water had reasonable and beneficial uses, then how could the SWFWMD tell people they couldn’t use it?

While water demand for drinking water and irrigation for crops are reasonable and beneficial, there are other uses of the Floridan Aquifer that are considered recreational or aesthetic. The water used for swimming pools or to keep golf courses green or to fill decorative fountains all comes from the Floridan Aquifer. During dry months, water for irrigation can add an additional 1 or 2 million gallons per day of demand onto an already stressed system.

The SWFWMD has already taken steps to hasten conservation by restricting watering of lawns to once per week and asking municipalities to enforce watering restrictions, but a more drastic management plan may be called for to further reduce demands on the Floridan Aquifer. I would propose that no new sod or landscape be installed during the dry months or during a drought. New sod and landscape is exempt from the once per week lawn watering restriction and is allowed to water every day. When whole subdivisions are being built, a vast quantity of water is used to ensure that the new home owners will have green lawns.

Tampa Bay Water undertook a large project to ensure that the people in the Tampa Bay area would have enough water and at the same time reduce withdrawals from groundwater. In 1999, Tampa Bay Water decided to build a $125 million desalination plant that would take water from the Gulf of Mexico and convert it into 25 million gallons of potable water per day. The desalination plant costs jumped higher and higher as the grand opening date kept getting pushed back. The original start date was for 2003 and the plant officially began full operation in January of 2008. The final price tag for the plant was many times more than the original estimate. However, by implementing the desalination plant, Tampa Bay Water will be able to cut groundwater withdrawals by approximately 40%. As nearly 120 different countries now have desalination capabilities, the State of Florida may turn to additional desalination facilities to further reduce their dependence on groundwater (Voutchkov, 2004).

Another component of the management of the Floridan Aquifer, above and beyond what has already been accomplished is with respect to the hydrology of the Peace River. The Peace River was historically a gaining stream, meaning that water from the Floridan Aquifer supplied the base flow for the river. Now the Peace River is a “losing” stream, meaning that water escapes from the river into the aquifer via sinkholes. Water that goes into the aquifer now never reaches the important estuary of Charlotte Harbor or the water treatment plants that supply potable water to customers downstream. Part of my management strategy would be to cover the sinkholes within the streambed of the Peace River and not allow any water to enter the aquifer from the river.

This part of the management of the system may be counterintuitive: why not let the water enter the aquifer as recharge? There are greater implications for the Peace River water entering the aquifer rather than completing its journey down to Charlotte Harbor. Habitats along the river bed are dependent upon certain flows. Also the estuary at Charlotte Harbor, which serves as a nursery for many types of sport fish, depends on the freshwater inputs from the Peace River to provide the proper mix of fresh and salt water. Again, this is an example of the connection between the withdrawal of resource from underground impacting surface systems, including important ecosystems that support tourist and fishery industries.

With more and more people moving to the Sunshine State, water demands will only become greater. Prioritizing the water supply seems to be the first step to sustainability. What is a reasonable and beneficial use? The next step is identifying alternative sources of water such as desalination to reduce the impacts from the current groundwater withdrawals. Finally, conservation and education will be essential to the success of any sustainability program. The benefits of the sustainability program will be reducing impacts to surface systems such as lakes, ponds, streams, springs and wetlands, return flows in the Peace River to near normal, reduce the rate of saltwater intrusion, and to preserve the groundwater supplies for future generations.

References

Dedekorkut, Asyin, November 2003. Chapter II: Tampa Bay Water Wars: From Crisis

To Collaboration. Florida State University. Adaptive Governance of Florida’s

Water Conflicts.

Glennon, Robert. 2002. Water Follies: Groundwater Pumping and the Fate of America's

Fresh Water. Washington, DC: Island Press.

Southwest Florida Water Management District. March 2006. Southern Water Use

Caution Area Recovery Strategy. Retrieved July 21, 2008 from

White, Nicola. May 30, 2008. Ambitious Project Aims to Get Peace River Flowing

Again. The Tampa Tribune.

Voutchkov, Nikolay. June 1, 2004. “A new resource for drinking water”, Public Works.