Rainfall this week was sufficient to bring Lake Okeechobee back up to the 11 feet above sea level mark. According to the U.S. Army Corps of Engineers, on June 13, the lake was at 11.08 feet.

Rainfall in the Caloosahatchee River basin has also meant that no water was released from Lake Okeechobee at Port Mayaca for Wednesday or Thursday. When local flow at the Franklin Lock is sufficient to meet the minimum target flow of 450 cubic feet per second (cfs) recently set by the corps, no water is released from the lake. On June 13, flow at the Franklin Lock averaged was 1,853 cfs., with zero flow at Moore Haven. That means all of the water flowing through the Franklin Lock was local basin runoff.

No lake water has been released to the east since March 30. The Port Mayaca Lock was open much of that time, but when the lake is below 12 feet above sea level, water from the St. Lucie Canal backflows into the lake. Earlier in the week, a very slight backflow (averaging 14 cfs) was reported at the Port Mayaca Lock. The Port Mayaca structure gates and lock were closed as of June 12.

For the seven-day average June 8-14, an average of 683 cfs flowed into the lake from the north in addition to rainfall that fell directly into Lake Okeechobee. During that time frame an average of 2,439 cfs flowed south and 307 cfs west into the Caloosahatchee River at Moore Haven.

Only one report of blue-green algae on Lake Okeechobee was sampled by the Florida Department of Environmental Protection during the past week. On June 12, a windblown blue-green algae buildup on the lake side of the Port Mayaca lock extended north and south approximately 200 yards in each direction. Clumps of blue-green algae appeared to be suspended in the water column. The water sample will be tested for microcystin.

Elsewhere in the state, during the week of June 8-14, FDEP sampled blue-green algae in Sarasota, Charlotte, Flagler, Hillsborough, Volusia, Alachua, Lee and Manatee counties. Since the start of the summer, only one FDEP water sample has tested above the 8 micrograms per liter level set by the Environmental Protection Agency as safe for human recreational contact. One June 5, a sample taken from Lake Okeechobee about 10 miles southwest of Port Mayaca had microcystin levels of 17 micrograms per liter. That same day, another sample taken from the lake about 5 miles west of Port Mayaca tested negative for microcystin, and a sample taken from a windblown concentration at the Port Mayaca Lock tested 1.48 micrograms per liter.