Bond Farm H Hydrologi gical E Enhancem emen ent 60% 0% De - PowerPoint PPT Presentation

Bond Farm H Hydrologi gical E Enhancem emen ent 60% 0% De Desi sign R Revi view 9/19/2018 Project Lead: SFWMD and FFWCC Impoundment Design by HDR and A.D.A. Engineering

Regional Overview

Project Overview • Broadly, the project goals are to improve hydroperiods and water levels in Cecil Webb and Yucca Pens, which have been historically impaired by roads, farms, and developments. • The primary mechanisms for improvement will be the conversion of the Bond farm and the Southwest Aggregates mine into water storage facilities, or flow equalization basins.

Project Overview • Phase I – consists of the design of the Bond Farm as a stand- alone component • The flow-way toward US41 is not being designed at this time, but is considered in terms of outfall placement • The average elevation is around 24 ft NAVD. The target water elevation for the Water Storage Area is 28 ft.-NAVD. 28 27 26 25 24 23 0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2,000 2,200 2,400 2,600 2,800

60% Design Presentation • Changes since 30% design: • Storage capacity revised from 2’ to 4’ • Berm heights raised from elevation 28 ft.-NAVD to 32 ft.-NAVD. • Seepage ditch proposed on outside perimeter of the project • Seepage water to be re-circulated back to inflow pump • SW Discharge Structure Added (for future use) • Culvert proposed at Sal Grade Rd. and Oil Well Road to improve flow to the south • Wet well for inflow pump designed; electrical coming from Correctional Institute • Omission of emergency overflow spillway • SFWMD is performing electronic review of the plans, specifications, modeling • 2 nd (and 3 rd ) Pre-application meetings held with FDEP in Ft. Myers and West Palm Beach (6/28/18 and 7/11/18, respectively). • HDR met with Army Corp regarding wildlife impacts (8/16/18). • HDR met with Charlotte County 9/18/18 regarding Zoning, Stormwater and Land Development Permits.

Overall Plan Changes

Northern Bond Farm FEB • East Conveyance – a naturally occurring low spot will help drain Cecil Webb into the Bond Farm • Northeast Conveyance – an external ditch will route water toward both inflow locations • Northwest Inflow Structure – this primary inflow location sits inside the existing SAL Grade ditch and will include a pump

FEB Cell Connectivity • A series of equalizer culverts will connect the eastern cell with the western cell • 4 total equalizer culverts

Southern Bond Farm FEB • Southeast Conveyance • Located within the existing SAL Grade ditch • Will direct flows exiting Bond Farm south into the I-75 ditch as they do today.

Revised External Levee Cross-Section Proposed Levee • External Levee - 10’ wide top at elevation 32 ft.- NAVD • Improvements to Revised Internal Levee Cross-Section SAL Grade Road – 15’ wide top at elevation 30 ft.- NAVD • Some areas will require fill, but most are close to elevation

East Conveyance • Inlet and culvert divert water under the access road from Cecil Webb to an existing canal • Culvert under the proposed levee will direct water from external canal to Bond Farm FEB • Flap gate allows one- directional flow only (east to west) • Rip rap outfall will reduce flow impacts

Northeast Conveyance • Conveyance ditch outside Bond Farm FEB • 15 ft. wide canal bottom • 2.5:1 side slopes • Bottom elev.: 20 ft.-NAVD • Top of Bank elev.: 25 ft.-NAVD • Connects existing eastern canal with existing SAL Grade ditch

Northwest Inflow Structure • 4ft culvert directs flows from the external conveyance ditch to the internal Sal Grade ditch • Flap gate allows one- directional flow only • Rip rap outfall will reduce flow impacts • Submersible pump (10,000 GPM) will allow additional flows when dH is zero or less

Southeast Conveyance • Concrete box culvert under levee will discharge the Bond Farm FEB • 8’x5’ • 70 linear feet • Sluice gate invert at 20.5 ft.-NAVD with 5 ft. max gate opening

Southwest Discharge Structure • 10’x10’ overflow concrete structure, top elevation 28.0 ft.-NAVD. • Twin 36” RCP, 121 LF @0.15% • Capped at 5’ outside property line

Equalizer Culverts • Connects the SAL Grade ditch in the eastern cell with the western cell • Allows cell water levels to equalize • 4 locations • 36” concrete culverts • 85 linear feet under SAL Grade Road • Inverts at 20.5 to 21.0 ft.- NAVD

Key Points • Levee at 32 ft.-NAVD with 10 to 15 foot top width • Inflow pump and one-directional culverts will move water from Cecil Webb into Bond Farm Flow Equalization Basin • Existing SAL Grade Road and ditch will remain in place for accessibility • 4 equalizer culverts will keep cells on both sides of the road at similar or equal elevations. • Outfall at south end of Bond Farm will continue to discharge to the same location as today. (This goes to Prairie Pines Preserve)