RUSKIN — For more than a decade, birdwatchers, politicians and scientists from across the globe have flocked to Cockroach Bay.
They have gazed at a maze of watery threads that weave around grassy islands, forming a coastal creek that shrivels and swells with the tides. They have looked out on a lagoon crafted from a stagnant pit into a piscine playground by bulldozers and track hoes instead of through centuries of wind and water.
The natural vistas carved from farm fields and shell mines have drawn visitors from England, Japan and across the United States. Environmentally, it's a less attractive picture.
"It looks good," said Tom Ries, principal scientist with Scheda Ecological Associates. "What it's missing is freshwater flow. … That freshwater is what's critical for juvenile fish."
By the end of the year, that's expected to change. In June, workers began the fifth and final phase of restoration at the Hillsborough County-owned preserve, a chapter that will include a freshwater pond described by Ries as the "heart" of the 500-acre retooling effort.
The $1 million final touch comes courtesy of Scheda's client, the Tampa Port Authority, which agreed to restore about 75 acres at Cockroach Bay in exchange for filling 10 acres of wetlands at Port Redwing in Gibsonton. Scheda designed the project, freeing money the Southwest Florida Water Management District had set aside for Cockroach to be used at the preserve's sister tract to the south known as Rock Pond.
Ed Bugel, senior engineer with the port authority, said port officials considered less costly options for replacing the Redwing wetlands but thought finishing the Cockroach restoration would provide a bigger environmental benefit.
The Cockroach project includes sculpting a large brackish pond that once was a shell pit into a shallow pool with gently sloping edges favored by wading birds and small fish. A hundred yards to the south is a smaller freshwater pit, which workers will fill to transform it into a more natural pond dotted with islands that will provide roosting and foraging opportunities.
Ries said the design also provides better water flow between the ponds and the already restored tidal creek, creating differences in salinity levels that will improve the fish habitat.
Richard Sullivan, Hillsborough's preserve manager, said the final phase also is expected to enhance visitors' recreational opportunities because it will link all of the saltwater features.
"They'll be able to travel through it in a canoe," Sullivan said.
One of the first steps in the project involved draining the two pits to allow heavy equipment to push dirt into position. Ries said the biggest challenge in the transformation is ensuring that polluted water doesn't make its way into the Cockroach Bay Aquatic Preserve, which is a designated Outstanding Florida Water worthy of special protection.
Even before restoration, the saltwater pond attracted enough concentrated bird activity that scientists at the Hillsborough County Environmental Protection Commission worried about excess nitrogen from years of animal droppings choking the bay and spiking algae blooms.
So Scheda included a series of polymer devices made to pull pollutants out of the water as it drains. Workers also built a settling pond to collect the drainage and further clean it before it flows into tributaries that lead to Little Cockroach Bay.
Previous phases of restoration began in 1996 as a cooperative effort of Hillsborough County and the water management district's Surface Water Improvement and Management program.
Brandt Henningsen, SWIM's chief environmental scientist, oversaw most of the work at Cockroach Bay. When he first saw the tract, it was a series of farm fields fringed by jungles of nuisance Brazilian pepper trees and dotted with mined-out shell pits.
The $5 million transformation has occurred in phases, as funding, fill material and often volunteer labor became available.
"It's been a pay-as-you-go project, involving a lot of very creative funding opportunities," Henningsen said. "This final phase will be the crowning touch."
One aspect that was not planned is a large mound of dirt stored at the site since 2004. At 50 feet high, it has become an observation station, offering a bird's-eye view of the coastal landscape and the Tampa skyline across the bay.
Dubbed "Mount Cockroach," the mound has hosted a number of gatherings, including a SWIM 20th anniversary party in 2007.
"It's actually become a public amenity," Henningsen said. "The first place anybody goes when they go to Cockroach Bay is Mount Cockroach."
The original 875-acre preserve was purchased through Hillsborough's Environmental Lands Acquisition and Preservation program in 1991, said county spokeswoman Kemly Green.
Recently added was a 43-acre wetland tract restored with federal dollars, plus two other parcels on the south side of Cockroach Bay Road, bringing the total land acreage to almost 1,000.
Sullivan, the preserve's manager, said Audubon Society members have counted more than 60 species of birds at the preserve in a single visit. He predicted the final restoration phase will bring even more.
"I can't wait to see the birds this winter," he said. "This place will be overrun with birds."
Susan Marschalk Green can be reached at email@example.com.