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
• f 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.

2,800 2,600 2,400 2,200 2,000 1,800 1,600 1,400 1,200 1,000 800 600 400 200 28 27 26 25 24 23

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
• 2nd (and 3rd) 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

• East Conveyance – a naturally
• ccurring 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

Northern Bond Farm FEB

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.

Proposed Levee

• External Levee - 10’

wide top at elevation 32 ft.- NAVD

• Improvements to

SAL Grade Road – 15’ wide top at elevation 30 ft.- NAVD

• Some areas will

require fill, but most are close to elevation

Revised External Levee Cross-Section Revised Internal Levee Cross-Section

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)