HomeMy WebLinkAbout2024 06 10 Awards and Presentation 103 Update of the Tuskawilla Crossings PondAWARDS AND PRESENTATIONS ITEM 103
CITY COMMISSION AGENDA | JUNE 10, 2024 REGULAR MEETING
TITLE
Design/Permitting Update of the Tuskawilla Crossings Pond
SUMMARY
David Hamstra, PE and Greg Teague, PE of Pegasus Engineering will provide the
Commission an update on their findings and design efforts to address the failed
stormwater pond facility.
FUNDING SOURCE
RECOMMENDATION
Pegasus Engineering will provide an update on their design and permitting efforts in
the redesign of the failed stormwater pond facility.
5
TUSKAWILLACROSSINGSSUBDIVISIONPOND1 REPAIR ANDREHABILITATIONProject Update on June 10, 202416
Commission Briefings and Project UpdatesPresentation #1City Commission briefing on October 23, 2023.Presentation #2City Commission project update on December 11, 2023.Presentation #3City Commission project update on June 10, 2024.27
PRESENTATION PART 1 –POND1 REPAIR ANDREHABILITATIONACTIVITIES38
2022 AERIALLOCATION49
EXISTINGCONDITIONSPLAN510
Pond 1 Repair and Rehabilitation Activities1. The berm failure that occurred on the north side of Pond 1 closer to the east end of the pond near Graceful Doe Loop. Special slope re-construction is required in the area of the berm failure as well as the east end of Pond 1 near 1533 Graceful Doe Loop.2. Side slope erosion has occurred around the entire pond perimeter.3. Erosion and scour at the outlet end of the five (5) storm pipes that discharge into Pond 1. The proposed outfall pipe improvements will include extending the pipes, lowering the outlet elevation and installing erosion control countermeasures in the form of rubble riprap.4. An existing rear yard drainage system located at 1533 Graceful Doe Loop will be modified to eliminate the current overland flow discharge into Pond 1.5. Pond 5 was designed and permitted with a control water level at elevation 39.75-ft, NAVD, which is nearly 20-feet above Pond 1 which was designed and permitted with a control water level at elevation 22.6-ft, NAVD. An underdrain located along the south side of the Cross Seminole Trail is proposed to intercept groundwater seepage from Pond 5, with a direct connection to the Pond 5 outfall system that bypasses Pond 1 to eventually discharge into the conservation area (Tract B-1).611
Pond 1 Repair and Rehabilitation Activities6. A grassed spillway located between the Pond 1 broad-crested concrete weir and the conservation area (Tract B-1) has a high erosion potential, especially when considering the magnitude of the discharges that were predicted in the previously approved permit for the regulatory storm events. Erosion control countermeasures in the form of a vegetated concrete block erosion control mat are proposed in combination with raised concrete curbing to confine the high velocity flows within the protected spillway area.7. The fiberglass skimmer for the Pond 1 broad-crested concrete weir is severely damaged and needs to be removed and replaced with an improved design that will be more resistant to any future damage.8. Vegetated concrete block erosion control mats are also proposed along the south and east sides of Pond 1 to prevent future erosion and provide improved protection for a sanitary sewer pipe and storm sewer pipe that were installed within the pond side slope with very little cover depth. Erosion of the Pond 1 side slope has previously exposed these pipes.712
PRESENTATION PART 2 –PHOTOGRAPHS FOR THEPOND1 REPAIR ANDREHABILITATIONACTIVITIES(TIMEPERMITTING)813
9Photograph Taken on December 6, 2023Photograph Taken on December 6, 2023The berm failure was “temporarily filled-in” by City staff in November 2023POND1 REPAIR ANDREHABILITATIONACTIVITY#1 –BERMFAILURE14
10POND1 REPAIR ANDREHABILITATIONACTIVITY#1 –BERMFAILUREA Contractor has already completed additional temporary repairs for the berm failurePhotograph Taken on June 2, 202415
POND1 REPAIR ANDREHABILITATIONACTIVITY#2 –SLOPEEROSION1116
Inflow Pipe from Wooded Vine DrivePond 1ScourHolePOND1 REPAIR ANDREHABILITATIONACTIVITY#3 –SCOUR ATPIPEOUTLETS1217
Inflow Pipe from Graceful Doe LoopScour HoleErosion Caused byOverland FlowPOND1 REPAIR ANDREHABILITATIONACTIVITY#4 –EXISTINGROOFDRAINAGESYSTEM FOR1533 GRACEFULDOELOOP1318
POND1 REPAIR ANDREHABILITATIONACTIVITY#5 –GROUNDWATERSEEPAGE FROMPOND514UnderdrainInterceptorPond 5Pond 1ConservationArea (Tract B-1)Sheet Pile19
Area of Erosion PotentialPond 1FiberglassSkimmerNutrient RemovalFiltration SystemTract B‐1(Wetland andConservation Area)Broad CrestedConcrete WeirPOND1 REPAIR ANDREHABILITATIONACTIVITY#6 –POND1 OVERFLOWWEIR1520
DEFICIENCY#7POND1 OVERFLOWWEIRSKIMMER1621
17Photograph Taken on November 18, 2023Photograph Taken on November 18, 2023POND1 REPAIR ANDREHABILITATIONACTIVITY#8 –PIPESEXPOSED BYPOND1 EROSION22
PRESENTATION PART 3 –FUTURESUTTONCROSSINGSDEVELOPMENT1823
Sutton CrossingsThe future Sutton Crossings development (by others) comprises 6.40 acres of presently undeveloped land that is located immediately north of Michael Blake Boulevard, just south of the State Road 434 and Tuskawilla Road intersection. 1924
Sutton Crossings – Stormwater Management IssuesTuskawilla Crossings Primary Drainage SystemStormwater runoff from the undeveloped land located north of Michael Blake Boulevard has not been accommodated within any of the stormwater management systems that serve Tuskawilla Crossings or The Savoy.Tuskawilla Crossings Secondary Drainage SystemThe existing storm sewer systems for Tuskawilla Crossings Pond 1 and The Savoy were not designed to include any stormwaterrunoff contributions from the undeveloped land located north of Michael Blake Boulevard.2025
Sutton Crossings – Stormwater Design CriteriaTuskawilla Crossings Primary Drainage SystemTuskawilla Crossings Pond 1 has sufficient volume to accommodate additional stormwater runoff contributed by the future land use (assumed 80% impervious surface) for Sutton Crossings.The City will require that Sutton Crossings provide on-site stormwater management to comply with the SJRMWD presumptive criteria for water quality treatment, as well as the additional nutrient removal criteria for the Lake Jesup Basin.2126
Sutton Crossings – Stormwater Design CriteriaTuskawilla Crossings Primary Drainage SystemIn addition to requesting construction authorizations for the repair and rehabilitation of Pond 1, the City’s new SJRWMD application for permit modification will also request an increase in the previously permitted project area for TuskawillaCrossings to encompass the future Sutton Crossings development.2227
Sutton Crossings – Stormwater Design CriteriaProject Area for Tuskawilla CrossingsPreviously Approved SJRWMD Permit = 133.32 acresFuture Sutton Crossings Development = 6.40 acresProject area for the City’s permit application = 139.72 acresDrainage Area for Tuskawilla Crossings Pond 1Previously Approved SJRWMD Permit = 47.72 acresFuture Sutton Crossings Development = 6.40 acresPond 1 drainage area for the City’s permit application = 54.12 acres2328
Sutton Crossings – Stormwater Design CriteriaTuskawilla Crossings Secondary Drainage SystemDue to hydraulic limitations imposed by the existing storm sewer system for Tuskawilla Crossings Pond 1, the City is regulating the maximum allowable discharge at the proposed point-of-connection for the future Sutton Crossings development. More specifically, a maximum discharge rate of 8 cfs can be contributed to the existing storm sewer system for TuskawillaCrossings Pond 1 from the future Sutton Crossings development at the proposed point-of-connection on Michael Blake Boulevard.2429
POND1 STORMSEWERSYSTEM2530
MAXIMUMALLOWABLEDISCHARGEFORSUTTONCROSSINGSAT THEPROPOSEDPOINT-OF-CONNECTION ONMICHAELBLAKEBOULEVARD2631
Sutton Crossings – Stormwater Design CriteriaMemorandum of UnderstandingA Memorandum of Understanding was prepared and transmitted on May 8, 2024 to officially document the stormwater management design criteria for the future Sutton Crossings development.2732
PRESENTATION PART 4 –CURRENT ANDFUTUREWORKEFFORTS2833
Current Work EffortsA Memorandum of Understanding related to the stormwatermanagement design criteria for the future Sutton Crossings development was transmitted on May 8, 2024.The City’s SJRWMD Application (No. 148395-4) for permit modification was submitted on May 24, 2024.Construction Plans (90% Progress) for the Pond 1 Repair and Rehabilitation were submitted to the SJRWMD on May 29, 2024.2934
Future Work EffortsContinued Coordination with SJRWMD representatives to secure an approved permitFinalize the Construction PlansAcquire the Temporary Construction Easements (TCEs)Prepare Bid Documents for a Public AdvertisementEvaluate Bids and Award the Construction ContractCommence Construction3035
Questions and AnswersDavid W. Hamstra, P.E., CFMStormwater Department Manager301 West State Road 434, Suite 309Winter Springs, Florida 32708Phone: 407-992-9160, ext. 309E-mail: david@pegasusengineering.net3136