Perry William
Everglades National Park, 40001 State Road 9339, Homestead, FL 33034, USA.
Ecotoxicology. 2004 Apr;13(3):185-93. doi: 10.1023/b:ectx.0000023564.10311.4a.
Approximately 70% less water flows through the Everglades ecosystem today compared with the historic Everglades, and the quality of the remaining water is often degraded. The regionally managed hydropattern does not follow the pre-drainage distribution, timing, and duration of the natural Everglades, nor can water move freely though the remaining Everglades. As a result, there have been significant reductions in wildlife and fish populations, their habitat, and the environmental services wetlands provide society. Both the problems of declining ecosystem health and the solutions to Everglades restoration center on restoring the quantity, quality, timing, and distribution of water. The Comprehensive Everglades Restoration Plan consists of over 60 civil works projects that will be designed and implemented over a 30 year period. At an estimated cost of 7.8 billion dollars, it seeks to correct an earlier attempt at water management in South Florida and improve water availability during the dry season and reduce flooding of urban and agricultural areas during the wet season. The plan calls for storage and controlled release from more than 217,000 acres of new reservoirs and wetland-based treatment areas and from over 300 underground aquifer storage and recovery wells. The plans assumes that during retention in stormwater treatment areas, the excess phosphorus, nitrogen, agrichemicals such as atrazine, diazinon, endosulfan, and other contaminants will be reduced before release into the natural areas. It also assumes that little or no change in water quality will occur during underground storage. To improve the hydraulic connectivity of natural areas, some of the extensive system of levees and canals within the Everglades will be removed in an effort to improve overland water flow. Most of the current planning has focused on water storage and restoring basic hydrology in the remnant natural areas and on phosphorus removal as a benchmark of water quality. The restoration plan, as approved by Congress, is conceptual and most of the details, including potential impacts of the plan on the natural system and the role of contaminants remain to be evaluated.
与历史上的大沼泽地相比,如今流经大沼泽地生态系统的水量减少了约70%,而且剩余水体的质量也常常下降。区域管理的水文模式既不遵循自然大沼泽地排水前的分布、时间和持续时间,水也无法在剩余的大沼泽地中自由流动。结果,野生动物和鱼类数量、它们的栖息地以及湿地为社会提供的环境服务都大幅减少。生态系统健康状况下降的问题以及大沼泽地恢复的解决方案都集中在恢复水的数量、质量、时间和分布上。大沼泽地综合恢复计划包括60多个土木工程项目,将在30年时间内进行设计和实施。该计划估计耗资78亿美元,旨在纠正佛罗里达州南部早期的水资源管理尝试,在旱季增加可用水量,并在雨季减少城市和农业地区的洪水。该计划要求在超过21.7万英亩的新水库和湿地处理区以及300多口地下含水层储存和回灌井进行蓄水和控制放水。该计划假定,在雨水处理区蓄水期间,过量的磷、氮、阿特拉津、二嗪农、硫丹等农用化学品以及其他污染物在排入自然区域之前会减少。它还假定地下储存期间水质几乎不会发生变化。为改善自然区域的水力连通性,大沼泽地内一些广泛的堤坝和运河系统将被拆除,以改善地表水流动。目前的大部分规划都集中在蓄水以及恢复残余自然区域的基本水文状况,以及将除磷作为水质基准。经国会批准的恢复计划只是概念性的,包括该计划对自然系统的潜在影响以及污染物的作用等大部分细节仍有待评估。