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
Lake Okeechobee that the lake's water quality was a State issue. The Florida Department of Environmental Protection and Martin County had carried out toxicity testing on the algae, but had not funded any work to clean up the water, and a FEMA spokesman said that "The state has robust capability to respond to emergencies and disasters." On June 23, 2017, the South Florida Water Management District was granted emergency permission to back pump clean water into Lake Okeechobee to save animals and plants in bloated water conservation areas." Lake Okeechobee sits in a shallow geological trough that also underlies the Kissimmee River