Lake Okeechobee Valley and the Everglades. The trough is underlain by clay deposits that compacted more than the limestone and sand deposits did along both coasts of peninsular Florida. Until about 6,000 years ago, the trough was dry land. As the sea level rose, the water table in Florida also rose and rainfall increased. From 6,000 to 4,000 years ago, wetlands formed building up peat deposits. Eventually the water flow into the area created a lake, drowning the wetlands. Along what is now the southern edge of the lake, the wetlands built up the layers of peat rapidly enough (reaching thick) to
Kissimmee/Okeechobee Lowland Kissimmee/Okeechobee Lowland The Kissimmee/Okeechobee Lowland is one of 47 distinct lake regions within the state of Florida, United States. The Kissimmee/Okeechobee is located in the central part of the state bounding Lake Okeechobee to the south and extending north to the Osceola Slope in Osceola County. It is bounded on the west by the Lake Wales Ridge system and on the east by the Eastern Flatlands. Counties within its borders are Osceola, Highlands, Polk, Okeechobee, and Glades. The Kissimmee/Okeechobee Lowland's name was established by Florida Department of Environmental Protection's Lake Bioassessment/Regionalization Initiative. Delineations are determined by soils, physiography, geology, hydrology,