Story by ALEXANDRA SUKHOMLINOVA
Dredging deep into Clam Bayou's future
A great blue heron wades through the shallows of Clam Bayou, tilts its head and looks down into the murky water.
But is there any food down there? And if there is, is it safe?
The heron is just one of the creatures — wild and human — that draw on the resources found in this 90-acre estuary system, which juts into the St. Petersburg metro area on Florida’s Gulf Coast.
But as urban development crowds the bayou, a debate simmers over the health of the estuary’s ecosystem. Some say these are troubled waters that hide a dangerous stew of toxic sediment and trucks of trash. Others say that preservation and restoration efforts are tackling the worst of the threats to the bayou, and the estuary’s sediment stores rich nutrients for the birds, fish and snakes that call it home.
At the heart of the debate is a more pointed controversy: Should dredging be added to current restoration efforts as a way to clean contaminated sediment from the estuary floor and deepen the water? Or would dredging be expensive overkill that does more to help recreational boaters than wildlife and could actually cause further harm to the ecosystem?
* * *One of the last naturally functioning estuaries of Boca Ciega Bay, Clam Bayou is a semienclosed body of water that combines freshwater from inland drainages with saltwater from the open sea. That mix of fresh and saltwater creates a unique habitat for hundreds of great blue heron, ibis, spoonbills, snowy egrets, fiddler crabs, oysters and other wildlife.
Like any estuary, Clam Bayou is prone to filling in, said Brandt Henningsen, chief environment scientist for the Southwest Florida Water Management District, the state agency responsible for overseeing the bayou. Sediment builds up on the shallow bottom and settles in the relatively still waters. The low tides can deposit more silt than they carry out.
But Clam Bayou faces particular pressure because of the storm water runoff system in St. Petersburg, which has accelerated the natural process of fill-in, Henningsen said. Now, every big storm carries an additional assault of trash and contaminated sediment into the estuary. And trash that washes into the estuary gets caught in mangrove roots rather than carried out to sea.
Those problems started in earnest in the 1950s, when St. Petersburg started to funnel storm water runoff into the bayou through drainage ditches. The runoff carries dirt and toxins from city streets into the estuary, where it settles in the sediment. And during especially heavy rainfall, the pollution that washes into Clam Bayou can include bigger items, which get caught in the mangrove roots rather than wash out to sea.
“With this rain today coming, there will be another truckload of garbage,” said Kurt Zuelsdorf of Nature Kayak Adventure, an environmental group dedicated to the bayou. “I’m afraid to go out there to see how bad a shape it’s in.”
Members of Zuelsdorf’s group make rounds of the bayou to identify and haul out what trash they can.
“I have marked tires, a kid’s swimming pool, a 500-gallon dumpster, a boat. Endless amounts of big items that me and my crew can’t get out are still there in that bayou,” he said.
The water management district, known as Swiftmud, targeted the bayou for restoration work in 1995. The sediment had built up so much in parts of the bayou that it became too shallow for manatees and dolphins. That’s also what prompted the debate over dredging as a way to excavate the sediment and deepen the estuary.
* * *Typically used to restore the depth of rivers and channels for commercial navigation, dredging can both benefit and harm an environment like Clam Bayou. Science shows both pros and cons, leaving the environmental and governmental agencies involved in the estuary conflicted about whether to support dredging as part of the restoration efforts.
In 1926, Clam Bayou was largely open water. Today more than half of its wetlands hold mangroves. A lagoon deep enough to support navigational channels in the mid-1950s now is 6 inches to 3 feet deep. Since 1950, about 50 percent of the bay's natural shoreline has disappeared.
As the rare habitat grew more threatened, Swiftmud teamed with St. Petersburg and Gulfport, the cities that share parts of the estuary, to work on a Clam Bayou storm-water treatment and habitat-restoration project.
Since then, Swiftmud has restored 20 acres of coastal habitat and improved water quality. Now it is focused on diverting storm water runoff, and the accompanying sediment and trash, into three artificial ponds that will be built on the St. Petersburg side of the bayou. This phase of the project also includes maintenance dredging of a section along the eastern shore of the bayou to improve tidal circulation.
“Once they redivert the water and stop the garbage coming in, the bayou is going to be a real gem,” Zuelsdorf said. “It’s already a gem in my book, but at least we won’t have to deal with the amazing amounts of garbage that are coming in off the streets.“
But the current storm water diversion project, which Swiftmud said will continue through 2009, doesn’t address the bigger controversy of dredging. And while Swiftmud, which under state law must approve any restoration work in the estuary, doesn’t plan to assess the pros and cons of dredging until 2010, the debate among Clam Bayou’s stakeholders continues.
The dredging question became a focal point of bureaucratic tension last year between Swiftmud and Gulfport.
In May this year, the Gulfport City Council adopted a resolution stating its concern about Swiftmud’s management of the bayou and called for deep dredging. That resolution came, in part, in response to a meeting a month earlier of several state, regional and federal environmental agencies. At that meeting, Swiftmud officials said the sediment of Clam Bayou was typical of that found throughout Tampa Bay, that it was capable of supporting the ecosystem, and that deep dredging would not improve the quality of the habitat.
But Gulfport City Councilman Bob Worthington said Swiftmud’s plans for the bayou were based on out-of-date data and did not respond to the estuary’s current conditions.
“It didn’t address the many years of silt forced in by the drainage ditches,” he said. “Their 1999 plan says that the water is contaminated. Today, Swiftmud says the water is not contaminated.
“If nothing has been removed, how can it not be contaminated?”
* * *The Gulfport resolution carries no enforcement power. Under state law, Swiftmud must approve any restoration plans for the wetlands. According to the law, dredging can be done only for environmental purposes and only to a depth somewhere between the natural high and low tidewater depths — in other words, no deeper than the water would naturally be at low tide. This regulation is in place to protect birds that feed in shallow water.
So not only is the basic benefit of dredging in dispute, so is the depth of any possible dredging.
One of the loudest voices in favor of deep dredging has come from Gulfport Water Watch, a nonprofit environmental advocacy group. Water Watch founder Al Davis said the group is interested in the preservation of Gulfport’s water resources, the success of the downtown businesses and the preservation of the “small-town atmosphere” of Gulfport.
Davis and many other members of Water Watch live around Clam Bayou. And for two years, the group lobbied Gulfport officials to support its demand for deep dredging of the estuary.
In an April 2007 letter to Florida Department of Environmental Protection, Water Watch suggested that the Bayou be dredged 4 to 6 feet below the mean water level as a way to clean the water, improve habitat quality and make any need for future dredging less dramatic.
“It needs to be dredged as deeply as possible,” Davis said. “It has to be dredged at least 4 feet below low-mean water level to restore the water circulation and to bring back the manatees and dolphins.”
But Swiftmud dismissed the proposal based on its evaluation of bayou habitat and sediment quality.
Davis countered that neither the city of St. Petersburg nor Swiftmud have taken an adequate interest in the restoration and preservation of Clam Bayou. And he said Swiftmud’s sampling of the water is inadequate.
“The bayou is dead,” he said. “There is trash on the bottom of it. In reality, it is depleted of oxygen and overabundant in nutrients.”
He also added the development around the bayou contributes to the contamination of the estuary.
But even Gulfport officials aren’t in agreement about what needs to happen at the estuary.
While the city council has endorsed dredging, Gulfport Vice Mayor Michele King vehemently opposes it, saying it isn’t warranted and would be too expensive.
“The Clam Bayou (depth) is between 6 inches and 3 feet roughly, and that’s what it’s been historically,” King said. “Boca Ciega Bay is not even as deep in many places as they want to make Clam Bayou.
“Dredging that deep creates dead water. It doesn’t move, there is no oxygen there and no one lives there.”
King said the only real benefit of deep dredging in the bayou would be to the people who live along it and those who want to put boats there.
“Anybody who needed a place to put a boat and didn’t want to pay the marina, they could anchor it there,” King said. She said they are couching their recreational interests as environmental interests.
That kind of finger-pointing has shaped some of the controversy over the future of Clam Bayou. King, who opposes dredging, is also a member of the Women’s Council of Realtors. Davis, who favors dredging, lives near the bayou and owns a boat.
But King said Gulfport is already built up and that new development can’t be blamed for additional pollution. And Davis said his “boat” is only 18 feet long, “the size of a kayak.”
The ultimate resolution will belong to Swiftmud, and deep dredging will happen only if the agency is convinced it would benefit the bayou habitat.
The major goal for Clam Bayou, according to Henningsen, is to restore and manage the habitat so it becomes stable enough to function in the future on its own, with little or no management from the agency.
“The habitat that is currently present in Clam Bayou is functioning well,” he said.