The Department of the Army, US Army Corps of Engineers (USACE), South Atlantic Division, Jacksonville District has a requirement for construction of the C-11 Impoundment and Mitigation Area A as part of the Broward County Water Preserve Areas (BCWPA), one of the elements of the Comprehensive Everglades Restoration Plan (CERP).

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• The Broward County Water Preserve Area (BCWPA), Contract 2 project consists of a portion of the overall C-11 Impoundment project. Contract 2 consists of construction of dam and levee embankment, a mitigation area, water control structures, environmentally sensitive area (ESA) systems, lake backfill, drainage conveyance, ancillary features, and associated clearing, grubbing, planting, borrow, and material processing.
• Contract 2 is the first of two construction phases (combined with future Contract 3) to complete the overall C-11 Impoundment component of the BCWPA project. The overall completed C-11 Impoundment will be an above-ground earthen reservoir targeted to have a total storage of 4,600 acre-feet with an effective interior area of approximately 1,053 acres and a normal pool water storage depth of approximately 4.7 ft.
• The Contract 2 dam embankment (D-511) will have an approximate height of 15ft (crest elevation of 18.8 ft NAVD88). The Contract 2 portion of D-511 embankment will include roughly 4,800 ft of slurry wall along the southern alignments between stations 111+00 to 146+00 (east) and stations 204+00 to 218+00 (west). The slurry wall will be 41 ft tall (EL 6.0 ft NAVD88 to EL -35.0 ft NAVD) with a typical width of 2.5 ft.
• The proposed Mitigation Area ‘A’, is located north of the impoundment. It will 113 acres of wetland marsh. Water levels within the mitigation area will fluctuate approximately 1.0 ft above average ground elevation (5.3 ft NAVD88). The levees surrounding the mitigation area will have an approximate height of 3 ft (crest elevation of 7.3 ft NAVD88).
• Contract 2 includes 12 total Water Control Structures:
  • Gated Culverts S-506A, S-508B, S-508D, and S-511
  • Ungated Culverts S-500A, S-505E, S-506B, S-508A, and S-509
  • Fixed, Broad-crested Weirs S-505B, S-505C, and S-505F
• There are two environmentally sensitive areas (ESAs) which are to be protected during construction and ultimately excluded from the project by means of embankment alignment. The ESAs will be protected from disturbance during construction and will be avoided by completed project features.
• Contact 2 includes a requirement to backfill the existing Central Lake and an existing borrow area. These features are existing quarry pits estimated to be up to 55 feet deep and filled with water. Backfill of the Central Lake and Borrow Area will primarily consist of onsite muck material. However, the Contractor will be provided approximately 10,800 cubic yards of stockpiled lime rock aggregate, located adjacent to SW 26th Street and the proposed construction staging area, which is approved to be placed in Central Lake.
• Contract 2 will require continuous stormwater management and conveyance of an approximate two square-mile drainage area north of the project site, which flows southward through the project site, plus any stormwater generated within the Contract 2 limits for the duration of the contract. Since stormwater flows will ultimately need to pass south through the future Contract 3 project limits for discharge into the C-11 Canal, stormwater management will include the following control requirements:
  • Stormwater system will convey a 100-year storm to the existing A/5 Canal outfall at the C-11 Canal.
  • Contractor will construct a temporary shallow drainage diversion ditch from the eastern C-511 Canal to the existing A/5 canal. The diversion ditch will be located along the boundary between the Contract 2 and Contract 3, in a zone of temporary construction limit for future resumption by others.
  • Contractor must not construct S-505F broad-crested weir until the eastern section of C-511 and the temporary diversion ditch to the existing A/5 canal are complete.
• Other project features and activities include clearing, grubbing, planting, borrow, material processing, boat ramps, soil cement embankment armoring, emergency stockpiles, instrumentation and monitoring stations, wetland preservation/protection, erosion control, and debris disposal.