Hydrogeologic Factors Affecting New Sinkhole Development in the Orlando Area, Florida
Hydrogeologic Factors Affecting New Sinkhole Development in the Orlando Area, Florida
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影响佛罗里达州奥兰多地区新天坑开发的水文地质因素
DOI：
10.1111/j.1745-6584.1992.tb01575.x
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发表时间：
1992
期刊：
影响因子：
2.6
通讯作者：
B. Beck
中科院分区：
文献类型：
--
作者：
W. Wilson;B. Beck
天坑的开发影响了世界上大约15%的陆地面积。新天坑的发展是非常具体的网站，但新天坑的发展和水文地质因素之间的一般协会可以建立有足够的历史记录的天坑发展的地区。在佛罗里达中东部的奥兰多地区，从1961年到1986年，至少有140个天坑形成。奥兰多地区位于一个覆盖层很厚的喀斯特地区，天坑是由覆盖层塌陷或较少见的覆盖层沉降形成的。平均每年有11个新的天坑坍塌。平均直径30.8英尺，平均深度15.5英尺。85%的新天坑发生在高补给区（10至15英寸/年），略高，桑迪山脊。在表层沉积物不太可能向下净侵蚀的排放区，很少或没有天坑。42%的新天坑发生在4月和5月，当时地下水位通常处于季节性低水位。当电位计表面下降到低于其模式5英尺时，单位时间内比预期更多的天坑开始出现。当电位面下降到其模式以下10英尺时，单位时间内的天坑数量开始超过预期的10倍。对地下水的抽取进行管理，以避免天坑易发地区的水位下降超过5英尺，这将最大限度地减少人为造成的新天坑。
Sinkhole development affects approximately 15 percent of the land area of the world. Development of new sinkholes is extremely site-specific, but general associations between new sinkhole development and hydrogeologic factors can be established for areas with adequate historical records of sinkhole development. In the Orlando area, east-central Florida, at least 140 sinkholes have developed between 1961 and 1986. The Orlando area is situated on a thickly mantled karst area, and sinkholes form by cover collapse or, less commonly, cover subsidence. On the average, 11 new sinkholes collapse each year. The mean diameter is 30.8 feet and the mean depth is 15.5 feet. Eighty-five percent of the new sinkholes occur in high recharge areas (10 to 15 inches/year) on slightly elevated, sandy ridges. Few or no sinkholes occur in discharge areas where net downward erosion of surficial sediment is very unlikely. Forty-two percent of all new sinkholes occur during April and May when ground-water levels are usually at seasonal low stands. When the potentiometric surface declines 5 feet below its mode, then more sinkholes than expected per unit time begin to occur. When the potentiometric surface declines 10 feet below its mode, then more than 10 times as many sinkholes as expected per unit time begin to occur. Management of ground-water withdrawal to avoid drawdowns in excess of 5 feet in sinkhole-prone areas will minimize new sinkhole development induced by man.