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Title: Environmental Assessment and Finding of No Significant Impact: Planned Temporary Deviation to Life Constraints on Water Conservation Area 3B, Site 71 for Relief of High Water Levels Within Water Conservation Area 3A: Broward and Miami-Dade Counties, Florida: Appendix A, Operational Strategy
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 Corps of Engineers, Jacksonville District is seeking approval from the South Atlantic Division for a Planned Temporary Deviation from the 2012 Water Control Plan and the Modified Water Deliveries Increment 2 and the Water Conservation Area 3 Decompartmentalization and Sheet Flow Enhancement Project Physical Model Operational Strategy in order to provide high water relief for WCA-3A. This action will increase the volume of water that is able to be sent to WCA-3B, out of WCA-3A. The temporary deviation will be needed until the WCA-3A stage, as measured by the average of the Site 63, Site 64, and Site 65 gages (3-gage average) falls below Zone A of the WCA-3A Regulation Schedule or November 30, 2018 whichever occurs first. A summary description and associated deviations for the structures the Corps will be responsible for is included below. This Operational Strategy includes additional background information and data analysis below. The WCA-3A, 3-gage average is 10.67 feet, NGVD, as of July 17, 2018, which is 0.87 feet above Zone D of the WCA-3A RS and 0.39 feet above the WCA-3A Increment 2 Action Line. WCA-3A received a historical high rainfall of 12.33 inches in the month of May which was 285% of the average for that month, as shown in Figure 1. However, WCA-3A has received approximately 70 % of the average rainfall in the months of June and July. Figures 2 and 3 illustrate the sharp rise of the WCA-3A 3-gage average into Zone A of the WCA-3A RS in May of this year and the elevation above the WCA-3A Increment 2 Action Line due to this rainfall. On June 29, 2018, SAJ requested two planned temporary deviations from the Water Conservation Area 2A (WCA-2A) RS and from the U.S. Fish and Wildlife Service (USFWS) Biological Opinion (BO) and the Increment 2.0 Operational Strategy to reduce S-11s flows into WCA-3A and to utilize S-344, S-343A, S-343B, S-12A, and S-12B to alleviate high water in WCA-3A pending ongoing consultation with the USFWS. SAD approved the request on June 30, 2018. The WCA-3A 3-gage average stage levels during May and June also coincides with the period-of-record (1962-2017) high water stage, for this time of year, in WCA-3A as indicated in the Exceedance Statistics Plot shown in Figure 3. Also, water levels in WCA-3A are not expected to lower quickly, as illustrated in the dynamic positional analysis provided on July 8th by the SFWMD in Figure 4. A summary of the current structure deviation operations is provided below.
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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