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HomeMy WebLinkAbout2023 10 23 Awards/Presentation 100 - Update on Tuskawilla Crossing Retention PondAWARDS AND PRESENTATIONS ITEM 100 CITY COMMISSION AGENDA | OCTOBER 23, 2023 REGULAR MEETING TITLE Update on Tuskawilla Crossing Retention Pond SUMMARY FUNDING SOURCE RECOMMENDATION Staff recommends the Commission receive the presentation from David Hamstra. 6 TUSKAWILLACROSSINGSSUBDIVISIONPOND1 REPAIR ANDREHABILITATIONCity Commission Briefing on October 23, 20237 Project OverviewThe permitted stormwater management system includes a total of five (5) wet detention stormwater ponds that discharge to wetlands and conservation areas identified on the subdivision plat as Tracts A, B-1, B-2, C, and D.The operation and maintenance phase of the stormwatermanagement system began on December 17, 2019 when District staff issued SJRWMD Permit 148395-3.This project pertains specifically to Pond 1, which is located south of State Road 434, and north and east of the Cross Seminole Trail.28 32021 AERIALLOCATION9 Project OverviewThe water quality volume provided within Pond 1 is recovered by a 6-inch diameter circular orifice that is connected to a proprietary Nutrient Removal Filtration System that was installed to address the District’s nutrient removal criteria for discharges to Lake Jessup. Overflow discharge from Pond 1 is conveyed to the adjacent wetland and conservation area (Tract B-1) by a broad crested concrete weir.Sometime in late August or early September 2023, a berm failure occurred on the north side of Pond 1 that resulted in a nearly vertical breach that rapidly drained the pond with significant soil loss and sediment deposition within the downstream wetland and conservation area (Tract B-1).Local rainfall stations indicate that a storm event with significant intensity occurred on September 8th.410 Project OverviewThe following deficiencies will need to be addressed as part of repairing and rehabilitating Pond 1, and it is very likely that additional deficiencies may also be discovered after engineering design commences.1. Repair and reconstruction of the berm breach. Berm reconstruction will also need to address under berm seepage into the wetland that appears on aerial photographs since at least January 2023, as well as other issues related to the drainage flow way that existed at this same location before the property was ever developed.2. Side slope erosion around the entire pond perimeter.3. Localized erosion of the pond berm and side slope caused by a roof and yard drainage system located at 1533 Graceful Doe Loop.4. Elevated pond control water level caused by the drawdown orifice and the Nutrient Removal Filtration System.511 Project Overview5. Damaged fiberglass skimmer for the broad crested concrete weir.6. Erosion potential between the broad crested concrete weir and the downstream wetland and conservation area (Tract B-1).7. Erosion and scour at the outlet ends of the three (3) storm pipes that discharge into Pond 1.8. Exposed storm pipe and joint along the Pond 5 outfall system just after the 90 degree turn along the south side of Pond 1.9. Horizontal sock drains that were left over from the original pond dewatering that have been exposed and ruptured by the rapid loss of water in Pond 1.612 DEFICIENCYPHOTOGRAPHS–BERMFAILURE, DOWNSTREAMSEDIMENTDEPOSITIONANDPRE-DEVELOPMENTDRAINAGEFLOWWAY13 814 915 1016 1117 12See the Enlarged ViewFor the Topographic SurveySPECIFICPURPOSESURVEY18 1324” RCPOutfall Pipe24” CMP Outfall Pipe(Pre‐development Flow Way)18” RCPOutfall PipeTract B‐1(Wetland and Conservation Area)TOPOGRAPHICSURVEY19 14Pond Berm was “cut” at this Location to Allow Site DrainageFrom Tuskawilla CrossingsDuring ConstructionTract B‐1(Wetland and Conservation Area)Pond 1TuskawillaCrossingsSEPTEMBER3, 201820 DEFICIENCYPHOTOGRAPHS–SIDESLOPEEROSIONAROUND THEENTIREPONDPERIMETER21 1622 1723 1824 DEFICIENCYPHOTOGRAPHS–EROSIONCAUSED BY AROOF ANDYARDDRAINAGESYSTEMLOCATED AT1533 GRACEFULDOELOOP25 201533 Graceful Doe LoopGutter Downspouts Connected to a Yard Drainage System26 21Pond 127 DEFICIENCYPHOTOGRAPHS–ELEVATEDPONDCONTROLWATERLEVEL28 23Pond 1FiberglassSkimmerDrawdownOrificeNutrient RemovalFiltration SystemTract B‐1(Wetland andConservation Area)Broad CrestedConcrete Weir29 2430 2531 2632 DEFICIENCYPHOTOGRAPHS–DAMAGEDFIBERGLASSSKIMMER FOR THEBROADCRESTEDCONCRETEWEIR33 28Pond 1FiberglassSkimmerDrawdownOrificeNutrient RemovalFiltration SystemTract B‐1(Wetland andConservation Area)Broad CrestedConcrete Weir34 2935 3036 DEFICIENCYPHOTOGRAPHS–EROSIONPOTENTIAL BETWEEN THEBROADCRESTEDCONCRETEWEIRANDTRACTB-1 (WETLAND ANDCONSERVATIONAREA)37 3238 33Area of Erosion PotentialPond 1FiberglassSkimmerNutrient RemovalFiltration SystemTract B‐1(Wetland andConservation Area)Broad CrestedConcrete Weir39 34Outfall Pipe from the Pond 1 Nutrient Removal Filtration SystemTract B‐1(Wetland andConservation Area)40 DEFICIENCYPHOTOGRAPHS–EROSION ANDSCOUR AT THEOUTLETENDS OFTHESTORMPIPES THATDISCHARGE INTOPOND141 36Inflow Pipe from Wooded Vine DrivePond 1ScourHole42 37Side Slope Erosion and ScourInflow Pipe from the Cross Seminole Trail43 38Inflow Pipe from Graceful Doe LoopScour HoleErosion Caused by a RearYard Drainage System Locatedat 1533 Graceful Doe Loop44 DEFICIENCYPHOTOGRAPHS–EXPOSEDSTORMPIPE ANDJOINTALONG THEPOND5 OUTFALLSYSTEM45 40Pond 1ScourHoleInflow Pipe from  theCross Seminole TrailSide Slope Erosionand Scour HolePond 5 Outfall Pipe46 41Pond 5 Outfall PipeCross Seminole Trail47 DEFICIENCYPHOTOGRAPHS–EXPOSED ANDRUPTUREDHORIZONTALSOCKDRAINSLEFTOVER FROM THEORIGINALPONDDEWATERING48 43PerforatedHDPE Pipe49 Questions and Answers44David W. Hamstra, P.E., CFMStormwater Department Manager301 West State Road 434, Suite 309Winter Springs, Florida 32708Phone: 407-992-9160, ext. 309E-mail: david@pegasusengineering.net50