South Floridas 730-sq-mile Lake Okeechobee has been likened to "a sleepy, fat baby, stirring into tantrums when winds rock her awake." But the dike-encircled lake also is a killer, having burst its banks in hurricanes twice in the 1920s, killing thousands.
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“堤……证明男人年代对水的恐惧and weather. Its a symbol of the Hurricane of 1928 that killed more than 2,000 people. Storytellers that knew of the many undocumented migrants say it was more like 4,000...coffins ran short...piles of people were buried in a large pit in Pahokee...bodies were burned in the fields...piled...two heads high," from The Knowing In The Neck; Memoir of a Girlhood In The Glades, a dissertation by Deborah L. Hall, Florida State University, 2004.
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| Soft.旧结构使用的沙子，贝壳。地图由西南佛罗里达水提供。 |
这场灾难引发了联邦政府接管1915年开始的毛绿色。土壁长143英里，32英尺，3英寸至45英尺，高6英寸。
The U.S. Army Corps of Engineers is confident that the dike, which protects 40,000 people, can withstand the winds of strong hurricanes. It is isolated from the sea so storm surge is limited to what the wind could do with lake water. But the engineers say heavy rains and regional flooding test the dike sorely. Leaks that began in 1995 have them worried enough to start modifying the oldest sections this fall.
一个专家小组报道：“当湖泊高度达到18.5英尺时，堤防的许多区域都有渗漏和管道问题。”一位专业小组研究了1998年研究堤防的专家小组。该研究得出的结论是，如果海拔高度达到21，则可能在一个或多个位置发生故障。新利18备用英尺，在一项100年的活动中预测的高度。它还说，“总体上”将有24到48小时的警告，但是堤防也可能突然失败而不会通知。
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Related Links:该墙在不可腐烂的泥土上包括多孔的石灰石，壳和沙子。今天的混音不会通过，但是在施工时是可以接受的。尽管如此，堤坝还是很少关注的数十年。但是近年来，尤其是在较旧的部分，不稳定和内部侵蚀的迹象可能引发崩溃。2002年和2003年的严重泄漏增加了翻新计划的紧迫性。
“管道和不her problems have been observed at elevation 18.5 and lower," says Brent Trauger, dam safety program manager with the Corps District office in Jacksonville, Fla. "If we exceed elevation 21, there is a potential for several failures. These improvements will protect us to elevation 26," he says. Corps studies show that a failure could cause a 1,000-ft breach and spread 5 ft of water over 40 square miles of towns and farmland.
在设计测试之后，9月30日，该军团在未来12年的四个合同中授予了4.6英里的合同，以硬化Mayaca和Belle Glade之间的“ Reach I”。后来尚未获得新利18备用网址国会授权的项目将继续从贝尔·格莱德（Belle Glade）到更多的避风港。
The $11.7-million contract, awarded to J. E. McAmis Inc., Chico, Calif., calls for inserting a 35-ft-deep "hanging" cutoff wall in the levee and cutting a landside drainage ditch. A geotechnical fabric liner in the drain will let the inevitable seepage out, but keep precious material from washing away, says Trauger. The hanging wall and drainage ditch design was chosen partly because going deep enough to sink the wall into a non-permeable layer is too expensive.
该设计还将项目保持在当前的BERM占地面内。1998年的一个估计使一条不可渗透的墙的成本在每英里1600万美元中加入了陆地上的渗水，而悬挂墙解决方案的成本约为每英里300万美元。
Engineers are concerned about static level elevations. On Oct. 17, the lake was at 15.6 ft. It hit 18.7 ft in 1947 and brushed 18.6 ft in 1995 and again in 1998. The Corps says wind-driven water temporarily has pushed the level to 25 ft, but that is not likely to trigger a failure.
With a berm height of 32 ft and more, waves are not likely to overtop the dike, either. It is long-term pressure of high water that worries engineers. That is why they keep 50,000 tons of sand, rock and stone stockpiled in 16 locations.
