Water managers report improved water quality in Lake Okeechobee
Water quality and water clarity in Lake Okeechobee, the largest freshwater lake in the southeastern United States, have improved substantially over the past two years. Aided by two relatively inactive hurricane seasons and subsequently low phosphorus inflows to the 730-square-mile lake, the South Florida Water Management District's (SFWMD) most recent water quality data for Lake Okeechobee indicate environmentally favorable conditions not seen in more than three years...
• SFWMD takes advantage of low lake levels to enhance plant and wildlife habitat; additional restoration work planned for this dry season
WEST PALM BEACH, FL, Nov. 26, 2007 -- Water quality and water clarity in Lake Okeechobee, the largest freshwater lake in the southeastern United States, have improved substantially over the past two years. Aided by two relatively inactive hurricane seasons and subsequently low phosphorus inflows to the 730-square-mile lake, the South Florida Water Management District's (SFWMD) most recent water quality data for Lake Okeechobee indicate environmentally favorable conditions not seen in more than three years.
Phosphorus levels in Lake Okeechobee recently registered an average of 77 parts per billion (ppb) across 27 monitoring sites, with near-shore areas at an average of 33 ppb showing the greatest improvement. One monitoring site registered 11 ppb phosphorus. After Hurricanes Frances and Jeanne in 2004, phosphorus levels in Lake Okeechobee reached more than 400 ppb; after Hurricane Wilma in 2005, levels averaged more than 300 ppb.
Despite winds and rainfall that swept along the coast last week due to Tropical Storm Noel, South Florida has experienced minimal storm activity during the past two hurricane seasons. This has vastly improved Lake Okeechobee's water clarity in near-shore areas, benefiting submerged aquatic vegetation. Just one year ago, less than 3,000 acres of submerged aquatic vegetation dotted the lake bottom; today, improved water clarity is allowing more sunlight to penetrate to the lake floor, helping these plants to proliferate. SFWMD scientists recently documented the recovery of submerged aquatic vegetation across more than 30,000 acres throughout Lake Okeechobee.
Low water levels also have created mud flats around the perimeter of the lake, attracting birds not normally seen in the Lake Okeechobee area to feed on insects and other invertebrates. More than 10,000 shorebirds of various species, including gulls, terns and sandpipers, were observed during a monitoring mission earlier this year. At the same time, low stages threaten apple snail populations, which is the primary food source for the endangered snail kite. The District, in partnership with the Harbor Branch Oceanographic Institute, is exploring methods to grow apple snails to return them to the lake when water levels rise.
To take advantage of the low water levels, the SFWMD is spearheading environmental enhancements, such as the scraping of excess sediments accumulated during past hurricanes and the planting of pond apple and bulrush in areas normally difficult to reach. Earlier this year, more than 1.9 million cubic yards of phosphorus-rich muck were scraped and trucked off Lake Okeechobee's dried-out shoreline, exposed by this year's drought. In addition, 1,000 native pond apple and cypress trees were planted on the rim canal and spoil islands near Clewiston, and 1,725 trees were planted near Moore Haven. Adding native trees where they once grew in abundance and re-exposing the lake's naturally sandy bottom are expected to further improve critical aquatic habitats when water levels return to normal.
In anticipation of continued low water levels well into the coming dry season, water managers are planning additional environmental enhancement projects, including new muck scraping initiatives, plantings and restocking of native apple snails to reinvigorate wading bird populations.
"Lake Okeechobee is going to be healthier as a result of this work," said Carol Ann Wehle, executive director of the SFWMD. "Although the drought and current water shortage have brought many difficult challenges, they also provide a real opportunity for environmental restoration in Lake Okeechobee and other sensitive areas."
The South Florida Water Management District is a regional, governmental agency that oversees the water resources in the southern half of the state -- 16 counties from Orlando to the Keys. It is the oldest and largest of the state's five water management districts. The agency mission is to manage and protect water resources of the region by balancing and improving water quality, flood control, natural systems and water supply. A key initiative is cleanup and restoration of the Everglades.