<P> 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 ." </P> <P> Lake Okeechobee sits in a shallow geological trough that also underlies the Kissimmee River 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 13 - to - 14 - foot or 4 - to - 4.3 - metre thick) to form a dam, until the lake overflowed into the Everglades . At its capacity, the lake holds 1 trillion US gallons (3.8 × 10 m) of water and is the headwaters of the Everglades . </P> <P> The floor of the lake is a limestone basin, with a maximum depth of 13 feet (4 m). Its water is somewhat murky from runoff from surrounding farmlands . The Army Corps of Engineers targets keeping the surface of the lake between 12.5 and 15.5 feet (4 and 5 m) above sea level . The lake is enclosed by a 40 feet (12 m) high Herbert Hoover Dike built by the U.S. Army Corps of Engineers after a hurricane in 1928 breached the old dike, flooding surrounding communities and claiming at least 2,500 lives . Water flows into Lake Okeechobee from several sources, including the Kissimmee River, Fisheating Creek, Lake Istokpoga, Taylor Creek, and smaller sources such as Nubbin Slough and Nicodemus Slough . The Kissimmee River is the largest source, providing more than 60% of the water flowing into Lake Okeechobee . Fisheating Creek is the second largest source for the lake, with about 9% of the total inflow . Prior to the 20th century, Lake Istokpoga was connected to the Kissimee River by Istokpoga Creek, but during the rainy season Lake Istokpoga overflowed, with the water flowing in a 40 km wide sheet across the Indian Prairie into Lake Okeechobee . Today Lake Istokpoga drains into Lake Okeechobee through several canals that drain the Indian Prairie, and into the Kissimmee River through a canal that has replaced Istokpoga Creek . Historically, outflow from the lake was by sheet flow over the Everglades, but most of the outflow has been diverted to dredged canals connecting to coastal rivers, such as the Miami Canal to the Miami River, the New River on the east, and the Caloosahatchee River (via the Caloosahatchee Canal and Lake Hicpochee) on the southwest . </P> <P> According to the U.S. Army Corps of Engineers, the Congressionally authorized uses for Lake Okeechobee include the following: </P>

Where does the water in lake okeechobee come from