Lake marshes dry; there’s no food for Everglades Snail Kites
PORT ST. LUCIE – Rainfall for the 2019-2020 Water Year has been slightly below average, according to the water conditions report presented by John Mitnik at the Feb. 1 meeting of the South Florida Water Management District governing board in Port St. Lucie.
The month of January ended up getting only 40 percent of the rain the district usually gets in January, Mr. Mitnik explained. Year to date, rainfall has been between the high 80s to the low 90s percent of average.
The largest deficit of rainfall has been in Water Conservation Area 3A (WCA 3) and Big Cypress Preserve.
“There has been a real deficit of rainfall in that area since September,” Mr. Mitnik explained.
In the Upper Chain of Lakes, East Lake Toho is being drawn down for enhancement project, he continued.
Lake Toho is slightly below schedule. Lake Kissimmee is slightly below schedule.
He said the U.S. Army Corps of Engineers is doing construction on the Kissimmee River, and the flows have to be adjusted for that construction.
“We’re trying to balance those flows to facilitate their construction,” he said. “It’s a little bit of a juggling act to try to manage some of those flows down the river.”
Lake Okeechobee appears to be on track to be around 12 feet on June 1. He said the modeling shows a 50 percent probability the lake will be at or below 12 feet on June 1.
In the past couple weeks, water managers have been moving water from the lake down the Miami Canal, Mr. Mitnik explained.
Because of the shortage of rainfall no water has been moving from WCA-3A to Everglades National Park.
He said they are moving about 250 cfs through the water control structures to Taylor Slough to try to get water to Florida Bay.
The corps has been releasing water from the lake to the Caloosahatchee River to prevent saltwater intrusion as needed year round. The SFWMD minimum flow level is 457 cubic feet per second (cfs) measured at the Franklin Lock. Lee County officials have asked for a minimum of 800 cfs, and stated 1,000 cfs is optimal. For the entire dry season, the corps has kept the flow at the Franklin Lock at an average of 650 cfs., supplementing local basin runoff with lake releases as needed.
For the last month, inflows to the lake totaled 29,000 acre feet of water; lake releases to the Caloosahatchee totaled 26,100 acre; and, lake releases south for agricultural and urban water supply and environmental protection totaled 32,400 acre feet.
Thanks to recent rainfall, including rain that fell directly into the Big O, the lake level has stayed relatively steady.
The National Drought Mitigation Center report shows an improved forecast for most of Florida, although some areas south and southwest of the lake are still abnormally dry.
The Climate Prediction Center is calling for slightly above average rain in February and for the rest of the dry season.
The U.S. Drought Monitor has improved overall, but some areas south of the lake are still in risk of drought.
In December, Broward County received excess rain, but it was mostly shunted out to tide, he said.
Mr. Mitnik said they are working to move water to Everglades National Park, but because WCA-3A is so dry, it will take time before that area is sufficiently saturated for water to move into the park.
He said the pumps are running at capacity 24/7.
“If the rain starts filling up WCA-3A, the water that we are putting at the top will start coming out the bottom,” he said.
“Are we putting Florida Bay last?” asked governing board member Jacqui Thurlow-Lippish?
“The situation we sit in today, it is the lack of water in the system,” explained Mr. Mitnik. “It is the rainfall deficit that is the challenge to Florida Bay.’
“There are areas in Florida Bay where we don’t have a way to get the water there, absent rainfall.”
“That’s why you need more storage,” he said. “For times like this.”
Cassandra Armstrong gave the ecological report. The Kissimmee River Basin system is fairly dry, she explained, “drier than we were one month ago and one year ago.” She said the corps has been keeping the flow of the Kissimmee River below 1,000 cfs due to the construction project in the portion of the river being restored. (The Kissimmee River Restoration Project, scheduled to be complete by the end of the year, will restore the twists and turns in about one-third of the original winding river.)
Lake Okeechobee is fairly dry, she explained. The western corner of the lake is mostly marsh. She said the lake level is about half a foot higher than it was a year ago, but these marshes are fairly dry and they have been dry.
Marshes over 14-feet elevation have been dry since 2018, she continued.
“This has implications for birds and submerged aquatic vegetation (SAV).”
In the marsh areas that have dried out there is no fish production, she said. There are no nesting birds because there is nothing for the birds to eat there.
“The snail kites are also not on the lake at this time,” Ms. Armstrong continued. “When the lake levels are below 14 feet, those marsh areas are going to dry out. The apple snails are not being produced so there is nothing for the kites to eat. So we are seeing zero snail kites on the lake.”
The good news is an increase in submerged aquatic vegetation (SAV) from about 5,000 acres last year to about 26,000 acres this year. The SAV is still recovering from the damage done by Hurricane Irma in 2017.
The SAV is mostly Chara in the southern region and eel grass in the northern area, she said.
Due to the low lake level, the lake has lost some SAV in the marshes, she continued. “We have not seen any recovery in Fisheating Bay.”
She said the NOAA imagery shows very low algae bloom potential in the lake at this time. She explained when the imagery shows blue colors, that means low potential. Red or orange colors means high potential for an algae bloom.