Five storm-water treatment areas (STAs) reduce the concentrations of nutrients and other pollutants from runoff before it enters the Everglades. Shown here is STA1-W, northwest of the Loxahatchee National Wildlife Refuge. Courtesy of South Florida Water Management District
Florida will construct flow equalization basins to help even out the water flow in the storm-water treatment areas it has already built to help limit the amount of phosphorous that enters the sensitive Everglades wetlands.
July 10, 2012—In a bid to achieve stringent new limits on the amount of phosphorus entering the Everglades, the Florida Department of Environmental Protection (DEP) and the South Florida Water Management District (SFWMD), of West Palm Beach, are moving forward with a new $880-million plan to significantly expand the capacity of facilities that are used to store and treat runoff upstream of the famed “River of Grass.” Implementation of the plan follows the recent approval by the U.S. Environmental Protection Agency (EPA) of permits submitted by the DEP for projects intended to improve water quality of runoff before it enters the Everglades.
Although the overall nutrient loads entering the Everglades have decreased in recent years as a result of previous restoration efforts, the ecologically sensitive area continues to receive more nutrients than it can handle, particularly phosphorus. Responding to an order from the U.S. District Court of the Southern District of Florida, the EPA issued in 2010 a list of actions to be conducted by the State of Florida as part of efforts to reduce phosphorus in water discharged to the Everglades. The EPA rejected the state’s first attempt to develop draft permits pertaining to phosphorus limits. Last September, the State of Florida presented an updated plan, prompting several months of negotiations between the state and federal entities. On June 6, the DEP submitted its updated permits to the EPA, which approved them 1 week later on June 13.
As part of the permits approved by the EPA, concentrations of total phosphorous as measured by a network of monitoring stations in the Everglades are not allowed to exceed a geometric mean of 10 ppb on an annual basis. To ensure that this ambient water quality standard is met, the SFWMD will be required to strictly limit phosphorous concentrations in discharges from the series of storm-water treatment areas (STAs) that it uses to cleanse runoff upstream of the Everglades. In fact, discharges from the STAs will be required to comply with an annual limit of 13 ppb of total phosphorus on a flow-weighted mean basis, says Ernie Barnett, the SFWMD’s director of Everglades policy.
As part of a 12-year, $880-million plan, the district will construct
three flow-equalization basins having a total storage capacity of
110,000 acre-ft, add two new storm-water treatment areas, and
increase the capacity of an existing treatment area. Courtesy
of South Florida Water Management District
The SFWMD—which worked with the DEP to devise the new Everglades plan—currently owns, operates, and maintains 5 STAs having a total of 57,000 acres of effective treatment area. The STAs use vegetation to treat runoff from agricultural areas located south of Lake Okeechobee but north of the Everglades. To achieve compliance with the new phosphorus limit, the SFWMD will add vast new storage facilities ahead of its existing STAs, while also expanding its network of treatment areas.
The work, which is to be performed in three phases between 2012 and 2024, will greatly improve the ability of the SFWMD to manage the STAs and optimize their performance during wet and dry periods, Barnett says. As biological systems, the STAs perform “remarkably well” when inflows are neither too great nor too small, he says. By contrast, peak flows during wet periods overload system capacity, while low or no flows during dry periods impair the ability of the vegetation in the STAs to effect treatment. By storing extreme flows during wet periods and maintaining more even water levels to the STAs during dry periods, the flow equalization basins (FEBs) will serve as a “moderator” of extreme hydrologic conditions, Barnett says. Although two of the three FEBs will provide “nominal” treatment capabilities, their greatest benefit to water quality will result from the flow equalization they provide, he notes.
The new FEBs will afford the SFWMD the “biggest environmental lift” of any of the plan’s components, Barnett says. For this reason, construction of the two largest FEBs will comprise the plan’s first phase, which is to occur from 2012 to 2016. “We put the two features that provide the most storage upfront in our implementation sequencing to capture that improvement to the treatment process,” he says. To be located upstream of two existing treatment areas known as STA-1 East and STA-1 West, one of the FEBs will have an area of slightly less than 1,000 acres and provide a storage capacity of roughly 45,000 acre-ft. Meanwhile, the second FEB will extend for approximately 14,000 acres and provide roughly 54,000 acre-ft of storage capacity, helping to regulate flows into the treatment areas known as STA-3/4 and STA-2.
As biological systems, the STAs experience fluctuations in
treatment capacity during extremely wet or dry periods. Large
flow equalization basins upstream of the STAs will moderate
flows into the treatment areas, improving their overall performance.
Courtesy of South Florida Water Management District
To be conducted from 2013 through 2018, Phase 2 of the plan calls for construction of a new 4,700 acre STA in the eastern Everglades adjacent to the Loxahatchee National Wildlife Refuge. Phase 3 will occur between 2018 and 2024 and entail the addition of an 1,800 acre STA, also adjacent to the wildlife refuge, as well as the construction of a 2,800 acre FEB in the western Everglades that will provide approximately 11,000 acre-ft of storage. All told, the three FEBs to be constructed as part of the new plan will provide roughly 110,000 acre-ft of storage capacity.
Phase 3 also will include earthwork within an 800 acre area in an existing STA to improve its treatment performance. Because it is higher in elevation than the rest of the STAs, the 800 acre area provides little effective treatment. By recontouring the area, the SFWMD aims to boost treatment performance within the overall STA while obviating the need to construct a new treatment area, Barnett says. Upon completion of the overall plan, the district’s many features for storing and treating runoff will have a combined area exceeding that of the State of Rhode Island, Barnett notes.
All told, the SFWMD will pay two-thirds of the cost of the $880-million plan, while the State of Florida will pay the remaining one-third. Of the project cost, roughly $850 million will go toward design and construction, Barnett says, and only $30 million is expected to be used for land acquisition, reflecting the fact that nearly all of the land to be used as part of the plan is already publicly owned. In addition, the plan calls for implementing source controls in certain agricultural areas to reduce phosphorus concentrations in runoff.
A pump station directs flows into STA 3/4, one of the largest such
areas operated by the South Florida Water Management District
as part of its efforts to cleanse runoff before it enters the
Everglades. Courtesy of South Florida Water Management District
Meanwhile, a recent report from the National Research Council (NRC) within the National Academies maintains that the Comprehensive Everglades Restoration Plan (CERP)—the 12-year, multibillion-dollar effort by the federal government and the State of Florida to restore the Everglades—has achieved some success, but has done little to improve conditions within the ecosystem’s central core. Released June 21, the report—which is titled Progress Toward Restoring the Everglades: The Fourth Biennial Review, 2012
—was prepared by the NRC’s Committee on Independent Scientific Review of Everglades Restoration Progress at the request of Congress. “The committee concludes that, 12 years into the CERP, little progress has been made on restoring the hydrology of the historical Everglades ecosystem; instead most of the recent progress has focused on the periphery,” according to the report. “To reverse ongoing declines in the central Everglades, it will be necessary to expedite restoration planning and implementation in this area while integrating water quality and hydrologic improvements,” the report stated.
“Unless near-term progress is made to improve water quantity and restore water flow, ecosystem losses will continue, many of which would require decades to centuries to recover,” said William Boggess, Ph.D., the chair of the NRC committee and professor and executive associate dean of the college of agricultural sciences at Oregon State University, Corvallis, in a June 21 release issued by the NRC. “However, bringing in more water, or even redistributing existing water flows before water quality is improved, risks introducing levels of contaminants that would have substantial effects on the ecosystem and possibly exceed legal limits,” Boggess said. “Analyzing the connections between water quality and quantity is one of the remaining challenges of the program, and will be a key component for moving forward.”
Along with focusing on efforts to restore the central core of the Everglades, any strategy for saving the Everglades must better integrate efforts to address water quality and water quantity, while finding a “new way to do business that avoids costly and unproductive delays in the project planning and authorization processes,” according to the report. Besides increased federal funding, additional monitoring is needed to ensure that restoration progress can be effectively assessed, the report stated.