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Atl Bch SWMP Presentation 02-27-2012 (02-24) City of Atlantic BeachCity of Atlantic Beach Stormwater Master Plan UpdateStormwater Master Plan Update February 27 2012 Meeting Purpose: Update City Commission on Meeting Purpose: Update City Commission on the Stormwater Master Plan Updatethe Stormwater Master Plan Update Overview of StormWater Master Plan (SWMP) Update and City • Implementation Present Capital Improvement Projects • Review and Update of Onsite Retention Requirement • Ditch Rehabilitation Options • The City has updated the SWMP to Account for The City has updated the SWMP to Account for Recent Development and InformationRecent Development and Information 1995 Citywide Master Plan1995 Citywide Master Plan  2001 Core City Project2001 Core City Project  2002 Master Plan Update2002 Master Plan Update  Hopkins CreekHopkins Creek  2010 Duval/FEMA Map updates2010 Duval/FEMA Map updates  2011 Citywide update2011 Citywide update  The City Implemented 22 CostThe City Implemented 22 Cost--effective effective Projects to Reduce Flooding Since 1999Projects to Reduce Flooding Since 1999 ProjectCost 1. 1999 Stormwater Improvements$415,000 2. W. 13th Street Drainage Improvements$39,000 3. Sherry Drive Reconstruction$1,375,000 4. Selva Marina Improvements$317,000 5. Core City$4,784,000 6. Dewees/Coquina Drainage & Paving Imps.$134,000 7. Church Rd. Water & Road Imps.$152,000 8. Plaza Road Turn Lane for Post Office$55,000 9. Jordan Street Paving & Drainage$109,000 Selva Marina -2001 10. Town Center Phase III$130,000 11. Country Club Lane$84,000 12. George & Dudley Drainage Improvements$98,000 13. Seminole Ditch Headwall$13,000 14. Ocean Blvd. -13th Street Drainage$139,000 15. Selva Grande Ditch Headwall$26,000 16. Ocean Blvd. -14th-16th Drainage$272,000 17. George St. Sidewalk & Drainage$36,000 18. Ardella Road Drainage Project$4,000 19. Royal Palms Stormwater Project$3,125,000 20. Cavalla Road Bulkheads$9,000 21. Selva Tierra Ditch Improvements$26,000 Cavalla Road 2007 22. Hopkins Creek Regional Pond$1,573,000 HOPKINS CREEK RSF Total$12,915,000 -2008 Aquatic Drive -2003 These Projects Also Saved the City Over $8 Million in Capital Costs and Preserved Historic Parks, Trees, and Wetlands Improved Flood Control LOS • T. S. Fay – Increased Treatment and Water • Quality Benefits New Park • Seminole Road Ditch Seminole Road Ditch 20072007 Core City Project Core City Project --20012001 Hopkins Creek Facility Hopkins Creek Facility and Park and Park --20082008 This Update AddressesThis Update Addresses Additional guidance and options for onsite stormwater Additional guidance and options for onsite stormwater •• volume controls (LID)volume controls (LID) Remaining nuisance ponding and system connectivityRemaining nuisance ponding and system connectivity •• Ditch safety and increased maintenance Ditch safety and increased maintenance •• FDEP NPDES MS4 permit support and emerging regulationsFDEP NPDES MS4 permit support and emerging regulations •• GIS CoordinationGIS Coordination •• Potential sea level rise impacts on the systemPotential sea level rise impacts on the system •• Stormwater Stormwater Management Management GoalsGoals Then and NowThen and Now Flood ControlFlood Control •• Water Water Quality ProtectionQuality Protection •• Wetlands Wetlands ManagementManagement LevelsLevels •• ofof Aquifer Aquifer Recharge Recharge •• ServiceService ConservationConservation •• Operation Operation and Maintenanceand Maintenance •• Community Community AcceptanceAcceptance •• SustainabilitySustainability Capital Improvement Plan (CIP)Capital Improvement Plan (CIP) CDM gathered information from several CDM gathered information from several sources to identify the next list of CIP Projectssources to identify the next list of CIP Projects Site visitsSite visits  Data reviewData review  Selection of 2 projects for detailed Selection of 2 projects for detailed  engineering evaluationengineering evaluation Conceptual improvementsConceptual improvements  Cost estimates for 10 projectsCost estimates for 10 projects  The Projects Were Scored by CDM and City The Projects Were Scored by CDM and City Staff for the Following CategoriesStaff for the Following Categories Public Safety •Based on potential risk from stormwater flooding and ponding Daily Traffic Impacted •Based on road classification and other access, with higher scores for arterial/collector roads Nuisance to Residents •Based on observed field conditions, topographic evaluation, and input from City staff History of Complaints Received •Based on complaints submitted by citizens to City staff Capital Improvement Plan EvaluationsCapital Improvement Plan Evaluations Capital Improvement Project Capital Improvement Project RankingRanking 35 locations evaluated35 locations evaluated –– 11 Ditches evaluated11 Ditches evaluated –– 10 cost estimates for higher 10 cost estimates for higher –– priority projectspriority projects 2 projects evaluated in detail2 projects evaluated in detail –– Project RankingProject Ranking A total of 42 problem areas were visited and evaluated as part of the evaluation. A total of 42 problem areas were visited and evaluated as part of the evaluation. •• Recommended CIPRecommended CIP Conceptual Capital RankProject Cost Estimate 1East Coast Drive -Atlantic to Ahern$ 360,000 2Seminole Road Ditch$ 3,400,000 Salt Air Drainage Upgrades -Magnolia (100 block)/Poinsettia Streets (100 & 200 Block)/Pine 3St$ 250,000 4Oceanwalk ditch (between OW and Selva Norte)$ 0 5100 / 200 / 300 Block Seminole$ 580,000 61080 West Plaza at Carnation and Gladiola at West Plaza$ 120,000 7Begonia street –West 6th to 9th$ 350,000 8Main Street between Levy and Stewart$ 530,000 9Mealy Street industrial area and Dudley Street west of Donner Park$ 25,000 10Robert St/ Lewis St/ Dudley St Ditch$ 171,000 TOTAL$ 5,846,000 Onsite Stormwater Controls and OptionsOnsite Stormwater Controls and Options Flooding Will Increase Without Stormwater Controls Flooding Will Increase Without Stormwater Controls and Onsite Controls are Most Costand Onsite Controls are Most Cost--effective effective City StreetsCity Streets •• Adjacent Adjacent •• propertiesproperties Downstream Downstream •• systemssystems Water quality Water quality •• ImpactsImpacts Reduced rechargeReduced recharge •• Current Ordinance OverviewCurrent Ordinance Overview Application of Low Impact Development concepts to Application of Low Impact Development concepts to •• redevelopment by more than 10% or 400 sqredevelopment by more than 10% or 400 sq--ft of impervious ft of impervious areaarea No net loss of onsite surface storage (to avoid displacing No net loss of onsite surface storage (to avoid displacing •• historic onsite stormwater onto adjacent parcels and to historic onsite stormwater onto adjacent parcels and to maintain existing aquifer recharge)maintain existing aquifer recharge) No increase in runoff volume for the 25 year 24 hour design No increase in runoff volume for the 25 year 24 hour design •• storm (to avoid increases in runoff volume, flooding and storm (to avoid increases in runoff volume, flooding and pollution to offsite while maintaining aquifer recharge) pollution to offsite while maintaining aquifer recharge) –– SJRWMD StandardSJRWMD Standard Onsite Stormwater Control EvaluationOnsite Stormwater Control Evaluation Test areaTest area •• Evaluation for existing and potential redevelopment Evaluation for existing and potential redevelopment •• conditionsconditions Impervious area, Impervious area, –– Groundwater tableGroundwater table –– Driveway / grassed area Select FillSelect Fill Considered four LID BMPsConsidered four LID BMPs •• PerforatedPerforated PipePipe ExfiltrationExfiltration Swales/retentionSwales/retention –– ExfiltrationExfiltration Rain gardens/bioretentionRain gardens/bioretention –– CourseCourse AggregateAggregate (Washed)(Washed) Filter FabricFilter Fabric Exfiltration trenchExfiltration trench –– tt 22--3 Fee3 Fee ExfiltrationExfiltration Seasonal High Water TableSeasonal High Water Table Underground storageUnderground storage –– Test Area EvaluatedTest Area Evaluated 81 Parcels 81 Parcels •• Total Area: 17.7 AcresTotal Area: 17.7 Acres •• Existing parcels impervious Existing parcels impervious •• Range: 0Range: 0--78%78% Composite : 32% imperviousComposite : 32% impervious •• Swales and RetentionSwales and Retention Can be a traditional swale or a shallow Can be a traditional swale or a shallow •• grassed yard retention area for dual usegrassed yard retention area for dual use Should be at least 1 ft above seasonal Should be at least 1 ft above seasonal •• high groundwater tablehigh groundwater table Should be maintainable by homeownerShould be maintainable by homeowner •• Bioretention (Rain Gardens)Bioretention (Rain Gardens) Special form of a swale or retentionSpecial form of a swale or retention •• Added aesthetic factor with plants/flowersAdded aesthetic factor with plants/flowers •• Must retain the required volume below the overflow Must retain the required volume below the overflow •• elevation elevation Exfiltration TrenchesExfiltration Trenches Underground optionUnderground option •• Can go under pavement or grassed areasCan go under pavement or grassed areas •• Filter wrap around perforated pipe and trenchFilter wrap around perforated pipe and trench •• Driveway/Grassed Surface Select FillSelect Fill PerforatedPerforated PipePipe ExfiltrationExfiltration ExfiltrationExfiltration CourseCourse AggregateAggregate 22--3 Feet3 Feet )) (Washed(Washed Filter FabricFilter Fabric ExfiltrationExfiltration ee Seasonal High Water TablSeasonal High Water Tabl Underground StorageUnderground Storage An alternative consists in excavating underground An alternative consists in excavating underground •• vaults/pipes that can provide runoff retention volume.vaults/pipes that can provide runoff retention volume. Access required for maintenance.Access required for maintenance. •• Onsite Stormater Controls are the Most CostOnsite Stormater Controls are the Most Cost-- Effective and Practicable OptionEffective and Practicable Option Swale/Swale/ RetentionRetention Conceptual Costs to Meet the Current Conceptual Costs to Meet the Current OrdinanceOrdinance Swales or yard retention are the most costSwales or yard retention are the most cost--effective effective •• controls and allow for dual usecontrols and allow for dual use Based on all parcels applying the same BMP typeBased on all parcels applying the same BMP type •• Offsite Swale/ Exfiltration Underground BioretentionUnderground RetentionTrenchVault Vault Test Area $18,300$144,100$210,700$352,500$673,000 Total Cost Ratio36.84.73.21.91.0 Cost per $200$2,900$4,300$7,200$13,700 Parcel Cost/cu-ft$0.40$2.80$4.10$6.80$13.10 The City is already providing a credit for infiltrationThe City is already providing a credit for infiltration Soil Boring Information Credit for storage available between Credit for storage available between •• the BMP and 1+ ft above the seasonal the BMP and 1+ ft above the seasonal high groundwater elevationhigh groundwater elevation Further credit refinement would Further credit refinement would •• require additional groundwater and require additional groundwater and soil datasoil data Maintain the current credit based on Maintain the current credit based on •• depth to groundwater, given the depth to groundwater, given the current data available current data available Ditch Maintenance and Capital ImprovementsDitch Maintenance and Capital Improvements Ditch Maintenance is a priority for the Ditch Maintenance is a priority for the Stormwater DivisionStormwater Division Inventory of City Stormwater Infrastructure Underground pipes140,000 LF Swale/Ditch 36,000 LF Wet Ditch/Channel 38,000 LF Baffle Box 3 UN Culvert Crossing 6 UN Special Equipment: Wet Detention Ponds6 UN Menzi Muck Machine Weirs4 UN Pump Stations1 UN Dry Retention Ponds2 UN Outfalls5 UN CDM Inspected Several Major DitchesCDM Inspected Several Major Ditches Flood ControlFlood Control Water Quality Water Quality  Traffic/Pedestrian SafetyTraffic/Pedestrian Safety Private PropertyPrivate Property  Tree Protection/City aestheticsTree Protection/City aesthetics Life Cycle CostLife Cycle Cost  Levy Road Seminole Road Robert Street Ditch–FDOT 11 Ditches Evaluated mfs1 Evaluation of • Alternatives: 1 Dynamic evaluation: 5 • Rational method: 5 • Slide 29 mfs1 Too much info for Commission? Michael Schmidt, 2/24/2012 Ditch Rehabilitation and Maintenance Ditch Rehabilitation and Maintenance EvaluationsEvaluations Ownership and AccessOwnership and Access •• EasementsEasements –– RightsRights--ofof--way (ROWs)way (ROWs) –– Level of ServiceLevel of Service •• MaintainabilityMaintainability •• EquipmentEquipment •• Ditch rehabilitation considers several factorsDitch rehabilitation considers several factors Adjacent Structures •Potential settling and vibration. Adjacent Roads •Excavation trench considerations and maintenance of traffic Environmental Resource Permit •Cannot increase peak flows or flood levels Maintenance •City needs an accessible easement or ROW Seminole Road Ditch Scored the 2Seminole Road Ditch Scored the 2Highest Highest ndnd Score Citywide due to Adjacent Arterial RoadScore Citywide due to Adjacent Arterial Road Safety Safety concernsconcerns  City has planted trees to reduce City has planted trees to reduce  hazardhazard Frequent complaintsFrequent complaints  Seminole Road Ditch EvaluationSeminole Road Ditch Evaluation Project ranked # 2 citywideProject ranked # 2 citywide  Detailed engineering Detailed engineering  evaluationevaluation Comparison of existing Comparison of existing  condition and 2 alternativescondition and 2 alternatives Required to maintain Required to maintain  hydraulic conveyance to hydraulic conveyance to avoid increasing peak flow avoid increasing peak flow rates downstreamrates downstream Seminole Road Ditch Seminole Road Ditch ––Potential ImprovementPotential Improvement Ditch enclosure to increase traffic safetyDitch enclosure to increase traffic safety  3 x 13 concrete box culvert3 x 13 concrete box culvert •• 2,140 ft of roadside swale with raised 2,140 ft of roadside swale with raised •• inletsinlets Cost Estimate: $2.5 M Cost Estimate: $2.5 M --$3.4 M$3.4 M  Includes excavation trench adjacent Includes excavation trench adjacent •• to Seminole Roadto Seminole Road Includes dewatering and MOTIncludes dewatering and MOT •• Includes engineering and permittingIncludes engineering and permitting •• Other potential solutions could be Other potential solutions could be  considered: considered: Regrade ditch and add retaining wallRegrade ditch and add retaining wall •• Additional outfall to Sherman Creek Additional outfall to Sherman Creek •• or the Sherman Creek Canalor the Sherman Creek Canal Robert Street Ditch is owned by FDOT and the Robert Street Ditch is owned by FDOT and the options available to the City are limited to north options available to the City are limited to north of Dudley Streetof Dudley Street FDOT:FDOT: •• Rehabilitation of existing ditch Rehabilitation of existing ditch –– Upsize of existing 30 inch pipe at Upsize of existing 30 inch pipe at –– Lewis Street to reduce peak Lewis Street to reduce peak velocitiesvelocities Atlantic BeachAtlantic Beach •• Potential upsize of existing 30 inch Potential upsize of existing 30 inch –– pipe at Dudley Streetpipe at Dudley Street JacksonvilleJacksonville •• Maintain the portion of the ditch Maintain the portion of the ditch –– north of Dutton Island Roadnorth of Dutton Island Road Robert Street Ditch Robert Street Ditch CDM estimated a conceptual cost for a CDM estimated a conceptual cost for a •• typical ditch (500 ft long, 6 ft deep, and 35 typical ditch (500 ft long, 6 ft deep, and 35 Turf Reinforcement ft wide)ft wide) $5,000 ~ $10,000 Construction cost is highly dependent on Construction cost is highly dependent on •• site specific factorssite specific factors T-Wall $350,000 ~ $450,000 Metal Sheet Pile Pipe + Swale $420,000 ~ $580,000 $600,000 ~ $750,000 • Sea Level Rise ConsiderationsSea Level Rise Considerations Potential Sea Level RisePotential Sea Level Rise Uncertainty Uncertainty ––Different projectionsDifferent projections •• Projections include measured data Projections include measured data •• (NOAA), as well as 3 sea rise scenarios (NOAA), as well as 3 sea rise scenarios based on USACE guidance based on USACE guidance Support long term planning in low lying Support long term planning in low lying •• areas which may experience higher and areas which may experience higher and more frequent tidesmore frequent tides Projects should include corrosion Projects should include corrosion •• prevention measures to extend their prevention measures to extend their useful lifeuseful life City of Atlantic BeachCity of Atlantic Beach Stormwater Master Plan UpdStormwater Master Plan Update February 27 2012February 27 2012