March 27, 2017
Estuary goes from drowning to drought in a year
By Chad Gillis
What a difference a year can make.
Last year the Caloosahatchee River estuary was blown several miles into the Gulf of Mexico after summer-like El Nino rains in January dumped about a foot of rain across the region.
Now incoming tides are pushing against the river, throwing off the estuary by pushing it inland.
"For the last four years now (the U.S. Army Corps of Engineers and South Florida Water Management District) has been trying to give us enough to keep the salinity at 10 (parts per thousand) at the Fort Myers Yacht Basin, and because of that the tape grass has been coming back," said Rick Bartleson, a water quality scientist with the Sanibel-Captiva Conservation Foundation. "Last year with the extra strong El Nino rains we had, salinity levels that were too low for the estuary and around Iona (oyster beds) were knocked back to nothing, but they’ve been getting some baby oysters there."
The yacht basin is used as a measuring stick for how much water should be released from upstream, the water management system that includes Lake Okeechobee, Florida Bay and 16 counties.
Releases of about 650 cubic feet per second at the W.P. Franklin Lock and Dam are needed during the dry season to keep the river healthy.
With below-average rain falling across the region and overall dry conditions, Lake Okeechobee releases did not meet that minimal goal for 53 straight days, according to foundation records.
Historically, the two water systems were not connected, but developers connected the Caloosahatchee and St. Lucie rivers to Lake Okeechobee in order to drain and develop the Everglades.
Water from the lake and runoff from lands to the north and south of the river are held back by a series of canals and dams, which are used to deliver water to the estuary and coast.
Regulations say water flow at the Franklin Lock and Dam should be kept between about 650 cubic feet per second to 2,800 cubic feet per second to keep the estuary healthy.
Flows are controlled by the U.S. Army Corps of Engineers with input from the South Florida Water Management District.
Okeechobee levels have fallen to about 12.7 feet above sea level, just inches above the Army Corps protocol to keep the lake between 12.5 and 15.5 feet above sea level.
"We've been doing seven days pulses that have averaged 650 cubic feet per second," said John Campbell, spokesman for the Army Corps office in Jacksonville. "There's been some variations, and it's not necessarily as precise as everyone wants."
Campbell said the lake typically recedes about six inches per month in the dry season, but the lake has been falling at a faster rate in recent weeks.
The good news is that the system should be able to handle an average tropical storm season, which starts June 1.
"Certainly last year at this time and getting into late spring the concern was would be able to get the lake level down to handle rainy season, but this year we'll be able to handle that," Campbell said. "We may even get below (12.5 feet)."
Last year brown-to-black waters blanketed the west and east coasts, and algal blooms caused fish kills and closed swimming beaches.
This spring, as is usually the case this time of year, coastal waters have been more emerald green to baby blue.
Rain is not forecast for the Fort Myers area this week, according to the National Weather Service in Ruskin.
The National Oceanic and Atmospheric Administration says there is an equal chance of above and below average rains in April, May and June.
Regular summer rains typically start in the first two weeks of June.
Until then, Bartleson and others will keep an eye out for low salinity levels in the liquid heart of Lee County.
"We have the whole food chain from larval fish and up to the fish that feed on the small fish, like snook and all of that," Bartleson said. "And in the upper estuary, they have a freshwater refuge and a feeding zone."
Connect with this reporter: Chad Gillis on Twitter.
By the numbers
3.3: inches of rainfall through March 26
57: Percent of rainfall on average that fell across the region this year
14.6: Inches of rainfall from January through March of 2016
220: Percent of rainfall on average that fell across the region in the first three months of 2016
12.7: Feet above level is what Lake Okeechobee levels were on March 27
Sources: South Florida Management District, Army Corps of Engineers