Bridges over Shark River Slough are restoring water flow into Everglades - Tampa Bay Times

thekflow.blogspot.com

There is a concrete sign of hope that the imperiled wet prairies, tree islands, mangrove marsh and shallow bay of Everglades National Park won’t become a wasteland as feared.

That sign is a pair of low bridges crossing over miles of Shark River Slough, the main path of water into the park.

At least a half-century of attempts to repair the Everglades have been a grinder of compromises, politics and grudging progress.

But in all of the complex parts and pieces of what is thought to be the world’s largest attempt at environmental restoration, the significance of the two bridges, finished in 2013 and last year, is unmistakable.

Related: Florida environmentalists want Legislature to create climate change committee

Audubon Florida declared the bridges “indisputably one of the most important elements of Everglades restoration.”

“Sea level rise and saltwater intrusion only make the bridging more important,” said Julie Wraithmell, executive director of Audubon Florida. “Restoring freshwater flow through the Everglades helps our coastal freshwater habitats resist higher sea levels, saltwater intrusion and coastal land loss. Everglades restoration is a cornerstone of South Florida’s resilience.”

Understanding the value of the bridges is an accomplishment amid the prolonged and convoluted tragedy of the Everglades.

A truck crosses a new bridging built along Tamiami Trail that allows more of Shark River Slough to flow south into Everglades National Park. [Kevin Spear | Orlando Sentinel] [ Orlando Sentinel ]

_________________________

STORIES IN THIS SERIES

Time is running out to save three Florida waterways threatened by climate change: the Apalachicola River, the Ocklawaha River and Shark River Slough

PART 1: Apalachicola, Ocklawaha, Shark River Slough: Florida’s magnificent, damaged waters at the brink of new assaults from changing climate.

PART 2: Apalachicola River: Hope wanes as state’s largest river succumbs to weakening current, dredging damage and imperiled forest

PART 3: Ocklawaha River: Reservoir from government blunder 50 years ago blocks free flow of water and wildife from Silver Springs to St. Johns River

PART 4: Shark River Slough: Main path of water into suffering Everglades park regaining potency, new life with bridges

PART 5: Apalachicola, Ocklawaha, Shark River Slough: Contested waters, different foes, varied outlooks as time runs short

_________________________

Man vs. nature

The historic rise of South Florida sugarcane farming turned the giant Lake Okeechobee into a toilet for polluted waters draining from as far as Central Florida and flushing ruinously via canals to coastal estuaries at Fort Myers and Stuart.

That bastardized plumbing wrecked nature’s genius: Rain falling near Orlando was meant to take a couple of years to migrate south, passing unhindered into and out of Lake Okeechobee, slipping invisibly through sawgrass plains where sugarcane tracts are today and finally hydrating wetlands behaving as a river — Shark River Slough — that flowed into an expanse known now as Everglades National Park.

[Map services and data available from U.S. Geological Survey, National Geospatial Program] [ Orlando Sentinel ]

The park was amputated from that 200 mile sweep of liquid life. Its vastness has suffered wildfires, vanishing wildlife, shriveling wetlands and the overall throes of dying of thirst.

Enter the bridges, one a mile long and the other comprised of two sections covering a total of 2.6 miles. They were designed to reconnect Shark River Slough with Everglades National Park with a freer flow of badly needed water. Several more miles of bridging is in the works.

For the people who know the Everglades’ dispiriting past and difficult future, the bridges have been visual fuel for improving morale and may provide encouragement for the many restoration sagas elsewhere in Florida.

“You can’t get water into the park without the bridging,” said Shannon Estenoz, policy director at the restoration-advocacy group, Everglades Foundation. “Once the first bridge became a thing, it was ‘OK, we get it.’ Folks understood the hydrologic value of doing it.”

Driving over the bridges provides fleeting scenery and a flash of disappointment: There is no place to pull over for the vista of Everglades National Park that extends unbroken to the horizon.

Built decades ago, Tamiami Trail blocks most of the Shark River Slough’s flow into Everglades National Park. A series of structures with water-control gates, like this one just along Tamiami Trail, allow a relatively small amount of slough water to enter the park. [Kevin Spear | Orlando Sentinel] [ Orlando Sentinel ]

The view is more explanatory from below.

Scientists Damon Rondeau and Erik Stabenau, both supervising hydrologists at the national park, provided an outing for a look at how the bridges fit in the big picture of Everglades restoration.

On a bright morning, they launched an airboat into the northeast corner of the national park from just off Tamiami Trail.

Nearly a century old, the road extends east as 8th Street into Miami’s Little Havana. It angles west as U.S. Highway 41 to Naples and Tampa.

Its name conjoined from Tampa and Miami, Tamiami Trail also cuts across the south-flowing Shark River Slough, blocking all but a small amount of slough flow let through culverts — until the bridges came.

Not quite earthbound or airborne, the airboat whisked across Shark River Slough until Rondeau chopped its power. The engine’s thunder idled, allowing gravity to suck the boat to a halt in an expanse of sawgrass and dense silence.

The stillness accentuated the busyness of snail kites, wheeling and hovering. The elegant birds distilled an Everglades moment. Also a moment was the ant-like traffic in the distance.

To the north was a segment of Tamiami Trail, not original roadway, but the 2.6 miles of bridging closely hugging the Glades.

Such an artificial feature so prominently displayed in other national park wilderness would be an eyesore.

But the bridging was mesmerizing, with cars and trucks as dots doodling back and forth over sawgrass plain and Shark River Slough.

“A former superintendent of the park described it as bridgehead,” Stabenau said. The superintendent was drawing on the strategic sense of establishing a foothold for advancement. “I’ve always like that.”

A 30-year-old National Park Service map warns that “life hangs by a thread in the Everglades” and that the water needed for the park is being siphoned away by “agricultural development and the continued mushrooming of metropolitan Miami.”

The map still speaks for today.

Related: Most Florida panthers found dead in 2020 were killed by cars

Water trouble is something park visitors would have little sense of while trekking along the Gumbo Limbo Trail or climbing the tower at Pa-hay-okee Overlook for Shark River Slough scenery.

For millions of visitors from around the world, Everglades National Park is an exquisitely curated museum of natural wonder.

For generations of scientists, the Everglades ecosystem is an unnatural wreck, with an incredibly large, unmet thirst.

Everglades National Park is bigger than any Florida county and nearly five times larger than the combined area of Fort Lauderdale, Miami, Orlando, St. Petersburg and Tampa.

It is the third-largest national park in the continental United States and abuts the nation’s sixth-most populous region. The park and metropolitan region are neighbors to 1,000 square miles of sugarcane farmland slashed from the Everglades south of Lake Okeechobee.

All three compete for water, and the park has been a big loser for decades. Much of the natural drainage of the greater Glades was overhauled with features such as canals to defeat nature.

“They were originally built to dehydrate, not hydrate the Everglades,” Rondeau said.

Restoring the flow

By the 1960s, President Richard Nixon urged efforts to “preserve the water supply of Everglades National Park.”

With too little water soaking the park landscape — its sloughs, prairies, cypress forests and mangrove swamps — too little water advances south to spill into Florida Bay, most of which is in the park.

Florida Bay is an 800-square-mile wedge of partly salty, partly fresh water between the bottom of the state’s peninsula and the arc of Florida Keys. It had thrived with aquatic plants, wildlife and the fish that made the Keys an anglers’ paradise.

But in repeated episodes, the bay received too little fresh water, which caused it to become excessively salty — or hyper saline in drought — which slaughtered most everything but harmful algae.

This is a from a newly bridged portion of Tamiami Trail, which for decades acted as dam that cut off most of the flow of Shark River Slough. The view of Everglades National Park to the south of the bridging stretches to the horizon. [Kevin Spear | Orlando Sentinel] [ Orlando Sentinel ]

From early on, there has been little hope of remaking the original Everglades.

“The goal is to create a smaller but complete Everglades system by replicating its original features,” said Audubon wetlands specialist Steven Parcells in 1993, testifying to Congress.

As pursued today, that will require huge reservoirs and marshes to hold and clean Orlando’s filthy water, and — rather than continuing to dispose of that water to the Gulf and Atlantic coasts — pumps, levees and seepage-barrier walls to funnel it under the bridges at Shark River Slough.

That’s the estimated $15 billion task called Everglades restoration.

Because Tamiami Trail has dammed Shark River Slough, the slough’s path into the park has become drier and grassier with sawgrass and less biologically fecund.

Sawgrass is the iconic vegetation of the Everglades river of grass. But it’s not so great for Glades biology when it grows densely and ubiquitously.

The slough’s deeper and open pools — devoid of sawgrass — are where ecological wonder happens, said Evelyn Gaiser, a Florida International University professor.

The Everglades concocts a special chemistry, Gaiser said. The limestone flooring of the Everglades dissolves into the water as calcium carbonate, which absorbs the tea-like stains of decaying plants.

Water lilies, skinny stems called spike rush and submerged plant called bladderwort, flourish in the slough’s crystal-clear pools.

Those plants are the housing or structure for periphyton, a slime of bacteria, microbes and plant debris. It looks regurgitated from a dog but it’s nutrition that empowers the Everglades food web.

“The slough habitat is the really the base of the food web that feeds all the way up into alligators and wading birds and all the charismatic and megafauna that we associate with the Everglades, said Gaiser.

The bridging of Tamiami Trail so far has boosted the flow of water in Shark River Slough incrementally. But that small flow has been a fountain of life, Gaiser said. Open pools and periphyton are returning.

“It’s remarkable,” she said. “None of us expected it to happen so fast.”

Contact Kevin Spear at kspear@orlandosentinel.com

This story was produced in partnership with the Florida Climate Reporting Network, a multi-newsroom initiative founded by the Miami Herald, the South Florida Sun Sentinel, The Palm Beach Post, the Orlando Sentinel, WLRN Public Media and the Tampa Bay Times.

Let's block ads! (Why?)

"flow" - Google News
December 31, 2020 at 05:00PM
https://ift.tt/3hyfg4M

Bridges over Shark River Slough are restoring water flow into Everglades - Tampa Bay Times
"flow" - Google News
https://ift.tt/2Sw6Z5O
https://ift.tt/2zNW3tO

Bagikan Berita Ini