The South Florida Water Management District recently issued an updated report titled Water Flow and Nutrient Loads to Lake Okeechobee and the St. Lucie and Caloosahatchee Estuaries in Water Years 2014-2018.
The SFWMD’s Water Year 2018 ran from May 1, 2017, to April 30, 2018.
Three “major climatic events” in 2017 — Tropical Storms Beatrix (June 5-7) and Philippe (Oct. 28) and Hurricane Irma (Sept. 10) — dumped an excess of rain on the Sunshine State. In fact, in South Florida, the June-October wet-season rainfall was 150 percent above average, according to the report, adding that 17.3 more inches of rain fell during that time than normally do.
The report also says that, during Water Year 2018, 89 percent of the water flow into Lake O came from north of the lake; 6 percent from the south; and 5 percent from the east.
Phosphorous inflow from the north was 89 percent; from the south, 7 percent; and from the east, 5 percent.
Nitrogen inflow from the north was 81 percent; from the south, 14 percent; and from the east, 5 percent.
No water, phosphorous or nitrogen flowed into Lake Okeechobee from the west, the report says.
The Marine Resources Council, based in Palm Bay, Fla., explains that “Too much nitrogen and phosphorous feed excessive algae and phytoplankton” (savetheirl.org).
Sources of phosphorous entering Lake O include wastewater, washwater (car-washing, for example) and fertilizers. Sources of nitrogen entering the lake include fertilizers, septic tanks and leaking wastewater infrastructure (source: savetheirl.org).
The two most significant summaries of Water Flow and Nutrient Loads to Lake Okeechobee and the St. Lucie and Caloosahatchee Estuaries in Water Years 2014-2018 are:
“• Historic wet conditions in WY (Water Year) 2018 resulted in significant wet-season runoff and nutrient loads for all three watersheds;
• Basins north of Lake Okeechobee contributed 89% of the total flow during WY 2018 and 94% over the 5-year average period.”
To read and/or download the complete report, visit https://apps.sfwmd.gov/webapps/publicMeetings/viewFile/17576