Sept. 19, 2017
Hurricane Irma update: Army Corps Releases More Water from Lake Okeechobee
By Chad Gillis
The Caloosahatchee River estuary doesn't really exist right now as Hurricane Irma rain washed it miles into the Gulf of Mexico. Now more water will be coming down the river after the Army Corps of Engineers announced plans to release anywhere from 2,000 to 4,000 cubic feet per second at the Franklin Lock starting Tuesday.
The estuary is harmed when levels reach 2,800 cubic feet per second or above. Water quality scientists say as much as 27,000 cubic feet (about 300 million gallons a day) ran down the river in the wake of Irma. "It’s still way up in the harm zone and it’s averaging for this week 13,000 cubic feet per second, so we’ve (already) passed the maximum harm," said Rick Bartleson, a water quality scientist at the Sanibel-Capiva Conservation Foundation on Sanibel. "What extra water does is it makes the freshwater go further out into the Gulf."
The Caloosahatchee and St. Lucie rivers were artificially connected to Lake Okeechobee long ago to drain the Everglades for development and farming. Now the rivers act as a flood plain for Lake Okeechobee. When water in the lake gets too high, the Army Corps of Engineers makes releases to the east and west coasts. Some water from the lake is moved south, but it's a fraction of what's seen on both coasts.
Army Corps protocols say the surface of the lake should be kept between 12.5 and 15.5 feet above sea level in order to protect thousands of residents living south of the lake and to provide drinking water for millions and even more water for farms.
The surface of the lake was at 15.5 feet above sea level Tuesday, and the Army Corps says it may go up to 17 feet or so within the next week. Army Corps leaders released water to the Caloosahatchee prior to Irma but stopped the flows to help ease flooding in the Fort Myers area. But it's time to open the water gates, Corps officials say.
“The challenges with high water that we saw on the Caloosahatchee last week have subsided,” said Col. Jason Kirk, commander of the Corps' Jacksonville office. “Starting releases from the lake now will help slow the rise so we can retain as much storage as possible in the lake for future precipitation events.”
Storm water runoff is a phrase used to describe water that falls in neighborhoods and then rushes to ditches, canals and eventually the Gulf of Mexico. Rain water sat on the landscape historically, but now most of the wetlands in Lee County have been converted to some type of development. Developed lands need drainage, so the system counters the natural rhythm of water here.
"You have more of your water running off instead of staying in wetlands, then (these events are) going to be worse," Bartleson said. "But now we’re down to about 10 percent wetlands in Lee County. That’s where the water used to go before it slowly came into the estuary. "The extra water also blocks sunlight, keeping it from reaching the sea grasses below.
John Cassani with Calusa Waterkeeper said recent flows have shut down most of the estuary and that Lake Okeechobee releases won't help the problems. "If the flows are at this level, there won’t be an estuary as defined, as a salinity gradient," Cassani said about balanced salt levels. "It’s just going to compress the estuary."
Bartleson said the ecological damage extends well into the Gulf of Mexico. "We’re making it all fresh from top to bottom on the outgoing tide," Bartleson said. "But if you double it, you’re extending the harm zone further out in the Gulf, and we don’t have a way to identify the number of plants and animals affected by that. So it’s not a good thing."