Sarasota County had a problem: Celery fields that had once been an economic asset were threatening to become an economic liability.
Farmers modified the land decades ago to retain water and nourish crops. Because it sloped to the south, excess water flowed in that direction. That wasn't a problem when the land was undeveloped, but large housing subdivisions began sprouting up. As developers paved the land to build new homes, the ground's ability to absorb water greatly decreased.
In June 1992, 27 inches of rain fell over three days while a tropical depression stalled in the Gulf of Mexico. More than a billion gallons of rain flowed into waterways, flooding at least 200 homes downstream of the farmland.
Something had to be done.
Floods No More
After analyzing the area's flooding patterns—which run northeast to southwest and into Sarasota Bay—Sarasota County Public Works Department engineers developed a plan to divert storm-water away from homes through a series of ditch canals, ponds, and mechanical flow-control devices.
They used computer models, including the EPA's Storm Water Management Model, to test the design against flooding conditions up to a 100-year rainfall event.
The county bought the problematic land from a local farmer, then cut drainage ditches into the property and framed it with a series of irrigation canals. Building on the fields' existing canal infrastructure, the design incorporates a network of diversion gates, outflow pipes, and pumps. It transformed the entire 400-acre site into open marshlands, deep ponds, and shallow pools edged by oak, willow, and pine trees.
The site is divided into three segments, which are comprised of defined areas of marshland, called cells, that act as a “treatment train.” The north cells receive water from an entry canal and have the deepest ponds. From there, the system channels water southwest into cells near the center of the site, and then into cells further south that empty into a creek. Ultimately, the treated water empties into Sarasota Bay.
After three years of construction, the site faced its first significant test in late 1997, when the county experienced two major 100-year rain events. Homes remained dry through both.
Instead of taxing all county residents to pay for the $27 million project, the county's stormwater division assessed only those who benefited. Owners of single-family homes on the 51,856 vulnerable parcels pay approximately $57 annually for 20 years. The assessment, supplemented with $13 million in grants from the Southwest Florida Water Management District and state funds, spared the public works department the arduous task of competing with other public agencies for general revenue funds.
The county used additional grant funds to install computerized monitoring stations. Today, 54 strategically placed sensors allow public works employees to remotely track the amount of water in the canals, measure accrued rainfall, graph results, and control water flow into and out of the system.
An Unexpected Benefit
In addition to restoring farmland to its original marshland state and recapturing the natural functions of a flood-plain, Saratoga County's stormwater management project provided an unexpected bonus—wildlife flourished. Nearly 200 species of birds, including sandhill cranes, bald eagles, peregrine falcons, and other endangered species, nest in its high grasses and weeds.
A third phase of the project is adding nearly 100 acres of recreational amenities called the Walker Tract (see sidebar at left).
As a newfound natural habitat for wildlife and a place of relaxation for families, Saratoga County's former celery fields are once again profitable.
— Powers is a public affairs specialist for the Federal Emergency Management Agency's (FEMA) Florida Long-Term Recovery Office.
To access data from Saratoga County's computerized rain-monitoring program, visit http://arms.co.sarasota.fl.us.
The Wild Life: A stormwater retention site is a top destination for both people and birds.