Construction set to begin on game-changing reservoir project

If you have recently driven along Range Line Road, near the southern perimeter of McCarty Ranch, you may have wondered at sporadic convoys of construction vehicles driving into the wilderness. A massive water management project is about to get underway on the site that will help alleviate freshwater discharges from the North Fork of the St. Lucie River.

On Feb. 18, construction is set to commence on the first of six shallow water reservoirs on the property. The entire project, which includes a 730-acre water disbursement area, will span almost 1,900 acres, and will be able to store up to 21 percent of excess stormwater from the C-23 canal – about 9 billion gallons annually. This is about 9 times the amount of water consumed per day in the entirety of South Florida.

Brad Macek, Utility Systems senior assistant director, says that once construction begins, area 1 should be completed within 6 months, hopefully in time for Florida’s rainy season, but certainly by September. The construction of area 1 will cost about $1.9 million, and will mostly entail a system of ditches and natural berms that will not only be ecologically sustainable – they may even help the ecosystem.

The reservoirs, colloquially referred to as “water farms,” will be adjacent to the C-23, so that water can be pumped directly into them from the canal. “The premise is that once we pull the water, a certain percentage is going to evaporate,” says Macek, “and a certain percentage is going to percolate down to the ground and recharge the water table.”

In addition to diverting fresh water from the canal, the water farm is also expected to extract 90,000 pounds of nitrogen and 18,000 pounds of phosphorus annually from the C-23. Let’s calculate this in normal bags of garden fertilizer: If we’re talking 1.5-pound bags with 20 percent nitrogen, for example, one would need 225 tons of these bags to equal the amount the farm will extract.

According to Macek, the original concept of McCarty Ranch was to use its 3,107 acres as an alternative water supply system for future population growth in the city. Three-hundred of those acres were for reservoirs, and the extension will add 100 more acres of water storage.

By the end of the year, the Utility Systems Department hopes to have a Master Water Supply Plan completed that will lay out two new water treatment plants for the city: a surface water treatment plant at McCarty that will pull water directly from the farm and purify it, and a reverse osmosis plant close-by, on Range Line Road. Both of these should be in operation within 20 years.

Port St. Lucie’s goal is to secure another 20 MGD (million gallons per day) of water supply to add to their existing 41.65 MGD. Currently, Port St. Lucie consumes about 16.15 MGD, but by 2040 the maximum water consumption is projected at 31.4 MGD.

The McCarty Ranch Water Project was closely modeled after Caulkins Ranch Water Farm in Martin County. Over the last four years, the Caulkins water farm, originally a 450-acre project, was given the go-ahead last October to expand by another 3,200 acres.

Charles Grande, a former St. Lucie County Commissioner and president of the River Coalition Defense Fund, says this success is mostly because the ground Caulkins is built on proved more porous than engineers had expected. More porosity allows more nutrients to flow through the basin into the soil, says Grande. This prevents sediment from building up on the bottom of the basin, that over time could send nutrients back into the water. Port St. Lucie Utilities won’t know the quality of the soil at McCarty Ranch until they start digging, though they hope to find similar success as their counterpart to the south.

Grande commends the current Port St. Lucie government for taking on the McCarty project. “This seems like they are thinking about the future,” he says, “and they are willing to make some investments that in my opinion will pay off, both in the short run and in the long run.”

Mayor Gregory Oravec, a long-time champion of McCarty Ranch, says the McCarty Ranch project only makes sense. “Only about 1 percent of Earth’s water is fresh and usable. And we’re throwing so much fresh water away, that we’re actually ruining the St. Lucie River and Indian River Lagoon, two of the most profoundly diverse ecosystems in the world. Rather than do that, why don’t we save it and be able to use it for our growing population?

“So I think we’re going to contribute to an overall solution, by doing what makes sense. I think it’s important, and I think it shows that cities can be an important part of solving large-scale issues.”

Oravec also highlights the current project as another step in the continuum of local environmental efforts, mentioning the highly successful septic to sewer conversion program in Port St. Lucie and the Eastern Watershed Improvement Project, a $36 million system of stormwater treatment areas and reservoirs in the eastern part of the city.

The entire McCarty project will cost $8 million, with a $180,000 yearly upkeep cost. The first area was funded by a $200,000 allocation from South Florida Water Management District’s Cooperative Grant Funding, and a $425,000 grant from Florida Department of Environmental Protection (FDEP). Currently the city is seeking another $644,000 from the FDEP, to aid in construction costs for area 2. The approval of this grant is anticipated in September of this year.

Article By: Adam Laten Willson

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