Lake Okeechobee levels begin to drop after Hurricane Irma
When Hurricane Irma charged across the state last month, coastal communities hammered by powerful storm surges drew most headlines. But inland Lake Okeechobee, the state’s massive 730-square-mile liquid heart, also took a hit.
Lake levels already high from the wettest rainy season in 86 years shot up 3 and a half feet, raising concerns about the shallow lake’s aging dike. Marshy edges that provide nesting habitat for endangered snail kites and fishing holes for anglers disappeared under brown water. With tropical storm force winds swirling across the lake like a giant Cuisinart for more than 24 hours, dirty water mixed with polluted sediment on the lake bottom.
About 5,300 acres of vegetation, made up mostly of cattails, also got uprooted and tossed into the mix, eliminating a protective boundary that helps keep turbid water from the lake’s interior away from its cleaner fringes.
A second blow could come from the decomposing cattails, which generate nutrients that can fuel algae blooms.
This week, for the first time in weeks, water levels in the lake began receding, a welcome sign. But the environmental consequences of Irma remain a concern.
“Turbidity in the lake itself, that’s a situation that’s going to persist for a while,” said environmental scientist Susan Gray, chief of Applied Sciences at the South Florida Water Management District. “After 2004 and 05 [when five hurricanes hit Florida] it took a year and a half to clear up.”
And all that dark water could cause even more submerged plants to die, said Audubon Florida’s Lake Okeechobee science coordinator Paul Gray.
“Pretty ugly out there right now,” he said in an email, predicting the plants would not survive the high water for so long.
To the south, the situation is more dire in vast water conservation areas where tree islands provide shelter for deer, raccoons, opossums and nesting wading birds across more than 1,300 square miles, said the district’s Everglades chief scientist, Fred Sklar. While the threat of flooding neighborhoods is far lower, the hits to wildlife could be unprecedented, he said.
By Sklar’s estimate, by the time the district can drain water, the islands will probably have been underwater for 288 days, about three weeks longer than the previous record.
While it’s not certain, Sklar expects a number will die and become ghost islands, losing habitat that can take centuries to build.
“No one has successfully brought back a tree island that has turned into a ghost. That doesn’t mean it’s impossible,” he said. “But you have to get the hydrology right first.”
Getting the hydrology right is part of the slow-moving Everglades restoration work being done by the district and the U.S. Army Corps of Engineers. A move by lawmakers this year to speed up work on a 14,000-acre reservoir is supposed to provide some relief during the rainy season when dirty lake water fouled by decades of farming, ranching and urban run-off gets flushed into coastal estuaries. Releases in the summer of 2016 left the Treasure Coast coated with slimy, smelly algae and killed oyster beds and seagrass in the Caloosahatchee.
But it’s not yet clear how much relief it will provide.
It’s also not clear when the new reservoir will be complete. Lawmakers have required the district and Corps to strike a deal and get a plan before Congress in two years, but extensions are possible. A status report is due in January.
In the meantime, the district has come up with another idea to end the releases: pump the lake water 3,000 feet underground into the boulder zone in deep injection wells normally used to store treated wastewater.
The plan would likely take two years to finalize and would only be used to avoid flushing the lake into the Caloosahatchee and St. Lucie rivers, said district lead hydrologist Bob Verrastro.
“Consider them estuary protection wells,” he said. “We’re trying to minimize the damaging flows to the estuaries.”
Environmentalists oppose the plan, saying injecting the water underground wastes it.
“Once that water is gone, it’s gone. And while there’s times when there is way too much water in the system, there are times when there’s not enough. It’s freshwater that’s just gone,” said National Parks Conservation Association Everglades program manager Cara Capp.
But Verrastro said even when all the storage components now included in restoration efforts are built, there will still be times when the system has too much water, like during Hurricane Irma. That’s when the wells would be used.
The number of wells has not yet been determined, but the district will likely run models on the effects of about 30 in clusters around canals that discharge into the lake, he said. Water would be pumped into the cavernous boulder zone beneath the aquifer that provides drinking water. It can stay there for hundreds of years before flowing underground into the deep ocean, he said.
Earlier this year, the U.S. Army Corps of Engineers removed the wells from their plan, saying too many questions remain — and prompting the district governing board to come up with its own plan for the injection wells now on the table.
Capp also worries that the wells will become a permanent fix, rather than a temporary patch,and pre-empt work that could ultimately be more beneficial to an ecosystem that most of the time desperately needs more freshwater. That’s particularly true as sea-rise risks worsen saltwater intrusion in South Florida’s shallow drinking water aquifer.
“What opportunities are we missing when we invest our money in deep injection wells instead of ecosystem restoration?” she said.
There’s also one more piece of the puzzle that needs to be completed to ease the high water: a two-mile bridge now being constructed along the Tamiami Trail. While it sits three counties away from the lake, when it’s done the bridge will unplug a crucial drain in the Everglades system, allowing water from the conservation areas to stream south into the watery marshes in Everglades National Park and out to Florida Bay.
“What you’re seeing in the lake is bad. What you’re seeing in the water conservation areas is horrible,” Gray said. “In the lake we see how it’s going to transition out, but in the water conservation areas, the inundation is historic.”
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