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Water storage project to help estuaries

By Staff | Nov 26, 2014

A water storage project with the space equivalent of 5,500 Olympic-sized swimming pools is expected to help in protecting water resources in Southwest Florida.

The Florida Department of Environmental Protection recently awarded $3 million to the South Florida Water Management District to fund what is being called “the Early Start phase” of the Caloosahatchee River West Basin Storage Reservoir, also known as C-43 Reservoir. The project will create up to 11,000 additional acre-feet of water storage in the area.

The “Early Start phase” of the C-43 Reservoir project centers on components that will provide interim water storage until the full C-43 Reservoir can be completed. A temporary storage facility in the southwest corner of the reservoir, demolition of structures within the site’s footprint and the construction of a small pump station and perimeter canal are parts of the components.

The cost-shared project between the federal government and the state of Florida is only one step towards improving water quality on both coasts of Florida.

“I think it will get us closer to having a bit more control over inflows into the Caloosahatchee estuary,” said Town of Fort Myers Beach Environmental Sciences Coordinator Keith Laakkonen. “We still need full funding on C-43 and several other projects in the water shed, but any little bit helps right now. Anything that will help us attenuate potentially damaging high season flows will help.”

The full construction project was approved by President Barack Obama back in June 2014. On May 13, 2014, U.S. Sen. Bill Nelson, D-FL, announced that the House and Senate committee overseeing the passage of the Water Resources Development Act -a bill authorizing federal funding for water projects nationwide- reached an agreement on the legislation.

The WRDA authorized the release of $626.6 million to finish construction of C-43. At the time, roughly $100 million was reported to be already spent in acquiring, designing and permitting the necessary land.

Upon completion, the early phase of the entire project will provide transitional water storage to a depth of roughly four feet on approximately 3,500 acres of the full C-43 Reservoir project site, according to the DEP report. It is expected to aid in the reduction of polluted discharges from Lake Okeechobee to local waterways now that the rainy season has ended.

“It is critical we take full advantage now during the dry season to generate as much additional water storage and treatment capacity as we can in South Florida,” said DEP Secretary Herschel T. Vinyard Jr. in a prepared statement. “Governor Scott and the Florida Legislature understand this and that’s why they’ve dedicated resources to grow our storage footprint and protect the Caloosahatchee and St. Lucie estuaries.”

Laakkonen echoed that sentiment.

“Potentially, it will help us in the dry season when we need to add more water to the estuary to prevent loss of tape grass in the upper estuary. Estuaries need balance,” he said. “Hopefully any storage options will help us reduce some of the very intense fresh water episodes during high flows and reduce some of the very intense salt water episodes while we are not getting sufficient rainfall into the watershed or from flows from Lake Okeechobee.”

South Florida Water Management District Executive Director Blake Guillory applauded DEP in its role.

“The district and the state put a priority on increasing water storage to protect south Florida’s coastal estuaries,” he said in the statement. “This funding support from DEP allows us to do just that by beginning early construction work on the C-43 Reservoir that provides increased storage onsite to protect the Caloosahatchee Estuary.”

Each summer, heavy rains fill Lake Okeechobee causing high flow regulatory freshwater releases to be discharged from the lake into the Caloosahatchee and St. Lucie rivers. This creates a disproportionate mix of fresh and salt water that eventually creates damage to the estuaries’ coastal habitats.

The lake releases are also known to involve back-pumped, nutrient-rich water with large amounts of phosphorus and nitrogen that negatively affects water quality.

SFWMD and the Army Corps of Engineers are known for owning a 50/50 partnership in managing the decisions for the large reservoir of the Greater Everglades system, which includes Lake O and many of its estuaries.

Long-term projects that are still being looked into include acquiring more land for the C-43 reservoir (designed to hold 170,000 acre feet of water) and Central Everglades Planning Project (reconnect Lake O south with Everglades National Park, but water needs to be treated/cleaned) and the restoration of Herbert Hoover Dike (to enhance structural integrity and provide additional storage).

According to the most recent “Caloosahatchee Condition Summary” provided by the Sanibel Captiva Conservation Foundation, flows to the estuary at the S79 WP Franklin Lock and Dam structure averaged 899 cubic feet per second. Flows are currently in the suitable range for tape grass in the upper estuary and oysters in the lower estuary, but light levels remain too low to sustain submerged aquatic vegetation at depth due to high colored dissolved organic matter.

In the lower estuary, the salinity in the Iona/McGregor area was recorded at 17 psu (practical salinity units) and the average salinity at Shell Point Retirement Community was 24 psu, known to be in the optimal range for oysters.

SCCF officials recommend to maintain flows between 800 and 1,000 CFS to meet established ecological targets within the estuary.

When completed, the C-43 Reservoir is said to help ensure a more natural, consistent flow of freshwater to the estuary. To restore and maintain the estuary during the dry season, the project will capture and store basin stormwater runoff, along with a portion of water discharged from Lake Okeechobee, and water will be slowly released into the Caloosahatchee, as needed.

The release of water during the right time of year may also assist in maintaining optimal water flows and levels for the year-round health of the estuary and provide recreational benefits.

“We must continue to be proactive in the protection of our environment and better prepare for the inevitability of rain in Southwest Florida,” said Sen. Lizbeth Benacquisto. “It’s extremely important that we take every opportunity to provide adequate water storage here in Southwest Florida, and the Early Start project helps do just that.”