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Title: Environmental Assessment and Finding of No Significant Impact: 2018 Planned Temporary Deviation to Affect Relief of High Water Levels Within Water Conservation Area 3A: Broward and Miami-Dad Counties, Florida
Authors: United States. Army. Corps of Engineers. Jacksonville District
Keywords: Everglades (Fla.)
Flood control
Environmental protection
Publisher: United States. Army. Corps of Engineers. Jacksonville District.
Abstract: The U.S. Army Corps of Engineers, Jacksonville District (Corps) is seeking a planned temporary deviation from the 2012 Water Control Plan, and approved deviations thereto, in order to provide relief from high water stages within WCA3A. The Proposed Action would be implemented July 1, 2018 and would terminate July 15, 2018. A series of mid-May storms have caused conditions to change rapidly from very dry conditions to very wet in South Florida, with Lake Okeechobee, the WCAs and the eastern coast of Florida accumulating most of the rainfall. Table 1 and Figure 2 illustrate the widespread period-of-record rainfall for the month of May for southern Florida, with the area as a whole receiving 301% of average rainfall. WCA 3 alone received 12.33 inches in precipitation since May 1, which is 285% of the average for this time of year. This May (2018) was the wettest on record within the SFWMD Service Area with 11.5 inches (previous record was 9.25 inches in 1895) recorded. This record area-wide rainfall has caused water stages in the three WCAs to rise above their maximum regulation schedules, as shown in Table 2. In addition, Lake Okeechobee and the Everglades Agricultural Area (EAA), which sends excess water south into the WCAs when capacity is available, has also received a significant amount of rainfall, further exacerbating the sharp rate of rise in the WCAs in May and June 2018. Table 2 shows the stage and excess volume of water contained in these areas. There are currently 908,725 acre-feet of excess water retained within the three primary WCAs, computed based on the volume difference between current water stages and the floor of the respective WCA Regulation Schedules. Due to the unprecedented rainfall during May 2018, WCA 1, WCA 2A and WCA 3A are all above Zone A of their respective regulation schedules, limiting the operational flexibility of the system. The stages within WCA 3A are the most concerning because construction, environmental constraints, and current system capacity limit the volume of water that can be moved out of the system. WCA 3A is the last downstream storage area in the C&SF Project, and it has extremely limited outlet capacity. Its regulation schedule is currently above the maximum regulation schedule and the maximum historical elevation for this time of the year, as shown in Figure 6. Immediate action is necessary to move flood water out of WCA 3A, and subsequently provide opportunities to move more water south out of the WCAs. Therefore, the Corps is initiating a planned temporary deviation from the approved 2012 Water Control Plan (and subsequent modifications hereto) for purposes of alleviating high water conditions within the project area. The Proposed Action is expected to mitigate for severe ecologic and economic losses that could result from prolonged high water levels. Loss of natural resources directly affects fisheries and fishing, seafood harvesting and ecotourism.
Description: Environmental Assessment / Finding of No Significant Impact
Rights: Approved for Public Release; Distribution is Unlimited
Appears in Collections:Environmental Documents

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