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Lake Okeechobee (), locally referred to as "The Lake", "Florida's Inland Sea",〔()〕 or "The Big O", is the largest freshwater lake in the state of Florida. It is the seventh largest freshwater lake in the United States〔Muller, Peter O. (2008). (Lake Okeechobee ) World Book Online Reference Center. Retrieved 12 Jan. 2008. 〕 and the second largest freshwater lake (the largest being Lake Michigan) contained entirely within the contiguous 48 states. However, it is the largest freshwater lake completely within a single one of the lower 48 states. Okeechobee covers , approximately half the size of the state of Rhode Island, and is exceptionally shallow for a lake of its size, with an average depth of only 9 feet (2.7 metres). The lake is divided between Glades, Okeechobee, Martin, Palm Beach, and Hendry counties. All five counties meet at one point near the center of the lake.〔(Counties of Florida map ) from U.S. Census Bureau.〕 ==History== 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 thick) to form a dam, until the lake overflowed into the Everglades.〔Lodge:110〕 At its capacity, the lake holds 1 trillion gallons of water〔 and is the headwaters of the Everglades.〔(South Florida Water Management District: Okeechobee Watershed Overview )〕 The name ''Okeechobee'' comes from the Hitchiti words ''oki'' (water) and ''chubi'' (big). The oldest known name for the lake was ''Mayaimi'' (also meaning "big water"), reported by Hernando de Escalante Fontaneda in the 16th century.〔Hahn:11〕 Slightly later in the 16th century René Goulaine de Laudonnière reported hearing about a large freshwater lake in southern Florida called ''Serrope''.〔Hann:148〕 By the 18th century the largely mythical lake was known to British mapmakers and chroniclers by the Spanish name ''Laguna de Espiritu Santo.''〔Hanna:32〕 In the early 19th century it was known as ''Mayacco Lake''〔Hanna:33〕 or ''Lake Mayaca'' after the Mayaca people, originally from the upper reaches of the St. Johns River, who moved near the lake in the early 18th century. The modern Port Mayaca on the east side of the lake preserves that name.〔Hann:99〕 The lake was also called ''Lake Macaco'' in the early 19th century.〔(【引用サイトリンク】url=http://fcit.usf.edu/florida/maps/pages/4100/f4176/f4176.htm )〕 The floor of the lake is a limestone basin, with a maximum depth of . Its water is somewhat murky from runoff from surrounding farmlands. The Army Corps of Engineers targets keeping the surface of the lake between above sea level. The lake is enclosed by a 9 metre (30 foot) 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.〔Lodge:105, 109〕〔Fisheating Creek Sub-Watershed Feasibility Study:11〕 The Kissimmee River is the largest source, providing more than 60% of the water flowing into Lake Okeechobee.〔Lodge:106〕〔Boning:212〕 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.〔Lodge:107, 109〕 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.〔Lodge:109〕 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. On the southern rim of Lake Okeechobee, three islands—Kreamer, Ritta, and Torey—were once settled by early pioneers. These settlements had a general store, post office, school, and town elections. Farming was the main vocation. The fertile land was challenging to farm because of the muddy muck. Over the first half of the twentieth century, farmers used agricultural tools—including tractors—to farm in the muck. By the 1960s, all of these settlements were abandoned. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lake Okeechobee」の詳細全文を読む スポンサード リンク
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