Downtown Green Infrastructure Assessment PRESENTED TO To w n o f F a i r f i e l d a n d Downtown Property Owners JULY 10, 2018 AGENDA  Background • Project Purpose • Project Funding  Existing Stormwater Drainage Systems • Current Limitations • Challenges and Potential Solutions  Types of Green Infrastructure  Potential Solutions  Conclusions BACKGROUND PROJECT PURPOSE Goals • Determine extent green infrastructure (GI) reduces runoff and flooding • Develop a resiliency strategy for downtown Fairfield using GI Assessment • Utility investigation • Subsurface Investigation • Model rainfall and runoff for existing and potential GI conditions • Develop GI best practice scenarios PROJECT FUNDING • A CDBG-DR was awarded through the State Department of Housing’s post-Sandy relief through HUD • This grant was intended for planning purposes only. Construction funding will need to be identified and applied for independently of this study EXISTING STO RMWATER DRAINAGE SYSTEM EXISTING DRAINAGE CONDITIONS • Existing drywells were found throughout the study area • Observed catch basins were found full of water or sediment, and some with vegetation • Large pipes were found to discharge into smaller pipes • Some areas drain to east, south, and Reef Road Current drainage system in the downtown area • Some area drain to west and Thorpe Road • Some areas may drain internally EXISTING LIMITATIONS • Red represents pipes and nodes with capacity problems • Yellow shows those with secondary issues • Link #17 (pipe crossing under the railroad) appears to be the main source of capacity issue • RR station parking lot runoff has one discharge point, and is combined with flow directed toward Unquowa Place CHALLENGES AND POTENTIAL SOLUTIONS • Model revealed flooding will occur for all design rainfall events • Capacity issues of the north-tosouth pipes under railroad cannot be easily resolved • Capacity issues of the north-tosouth pipe under Post Road cannot be easily resolved • GI may be able to reduce generation of stormwater Photo provided by Town of Fairfield • Where GI cannot reduce generation of stormwater, infiltration may be able to reduce runoff TYPES OF GREEN IN FRASTRUCTU RE TYPES OF GREEN INFRASTRUCTURE AND ASSOCIATED GRAY INFRASTRUCTURE • Green roofs and rooftop detention • Rooftop disconnects / rain barrels • Porous pavement and pavers • Tree planting / tree boxes • Bioretention • Rain gardens • Curb extension systems • Vegetated swales TYPES OF GREEN INFRASTRUCTURE TYPES OF GREEN INFRASTRUCTURE PERM EABLE PAVERS TYPES OF GREEN INFRASTRUCTURE BIORETENTION BASINS www.phillywatershed.org RAIN GARDENS LOCATED IN PARKING AREAS TYPES OF GREEN INFRASTRUCTURE TREE PLANTER TREE TRENCH WITH DRAIN INLETS TYPES OF GREEN INFRASTRUCTURE STREET BIORETENTION SYSTEMS WITH DIFFERENT INLET STRUCTURES TYPES OF GREEN INFRASTRUCTURE CU SOILS SUSPENDED PAVEMENT SYSTEMS TYPES OF GREEN INFRASTRUCTURE ENG m'l?iV?m mum '41 MM. bii?l I Ham-mun KT KN ?mu-I 'm's Iu'r Slum UP Ll? 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CONSIDER REPLACING THE EXISTING SIDEWALK IDENTIFY OPTIONS FOR GREEN ROOF ON SECTION OF SCHOOL ROOF . nun-n. w-Ilu WITH AN INFILTRATION SWALE . L. ., . POROUS ASPHALT PARKING AREA - - . . . i? CURB EXTENSION AND LID PLANTERS I I EXISTING DRYWELLS TO REMAIN (TYP. 6) ?mm-m- -. 1W -- A . VERIFY 1F EXISTING CATCH BASINS ARE DRYWELLS AND . IF NOT CONVERT TO DRYWELLS .. 3 - . - - . PERMEABLE PAVERS IN PARKING SPACES WITHIN. TRAIN STATION PARKING AREA . . T?ng? .- at?" . GREEN ROOF (TYP. {Jim -- PERMEABLE PAVERS IN PARALLEL . .4 - PARKING SPACES ALONG ROADWAY 14?; . Ci: ..-. 331' 1 . I .. 2:3. I 4 - . GREEN ROOF (TYPJ POROUS ASPHALT PARKING AREA - .. Ig, . (CONSIDER UNDERGROUND ?rl?m . CONVERT TO DRYWELLS . I CURB EXTENSION AND LIP PLANTERS . .I ?Neg II - .5 . ?-ing? . CONSIDER UNDERGROUND . PERMEABLE PAVERS IN PARALLEL PARKING SPACES El; . - . .r DETENTION IN ROADWAY PERMEABLE PAVERS IN PARALLEL PARKING I: -. CAPTURE STORMWATER IN VEGETATED BASIN IN PARK . . if: SPACES (BOTH SIDES OF ROADxix CONVERT EXISTING BASINS TO DRYWELLS 1CURB EXTENSION WITH INFILTRATION I OR ADD UNDERGROUND DETENTION . T: .- . II - PERMEABLE PAVERS IN PARKING .- .SPACES (TYPJ . ., . .CONVERT EXISTING BASINS To DRYWELLS . I OR ADD UNDERGROUND DETENTION I: '1 ., I . AREA A NORTH OF RAILROAD TRACKS Description • Located north of the business district • Stormwater flows south along Unquowa Road Typical Land Uses • Residential • Mosswood Condominium Complex Benefits of Selected Green Infrastructure Existing School Drop-Off Area • Permeable paved parking spaces capture initial rainfall, can be aesthetically pleasing • Infiltration basin can receive runoff and control overflow while colorful landscaping • Unquowa Road planters & bituminous concrete can control overflow and offer educational opportunities Potential Area with LID Planters and Porous Concrete AREA B NORTH OF RAILROAD TRACKS Description • 8-acre railroad parking • Southern area of Tomlinson Middle School with parking and athletic fields Typical Land Uses • Train station parking and athletic field Existing Middle School Conditions Benefits of Selected Green Infrastructure • Pavers and other parking lot options can reduce some stormwater generation despite poor subsurface conditions • The eco basin design accepts significant stormwater volumes • The eco basin concept can be installed below-grade, allowing usage of the surface Potential Eco Basin AREA C SOUTH OF RAILROAD TRACKS Description • Carter Henry Drive and adjacent areas Typical Land Uses • Commercial such as Bodega Taco Bar, Fairfield Country Motor Sport & The Label Exchange Benefits of Selected Green Infrastructure Existing Parking Area • Permeable paved parking and porous asphalt allow stormwater infiltration • Green roof systems can drastically reduce runoff, while also cooling their respective building • Green infrastructure sidewalk planters reduce runoff and provide attractive landscaping • Potential for 42% reduction of peak flow from 1-year rain event Potential Permeable Parking Area AREA D SOUTH OF RAILROAD TRACKS Description • A smaller area, primarily Unquowa Place Typical Land Uses • Garner Golf, other businesses Benefits of Selected Green Infrastructure Lawn on the Corner of Unquowa Place • Rain gardens capture stormwater, while creating habitat • Permeable paved parking along Unquowa place would reduce runoff • GI urban planters reduce sidewalk runoff, provide attractive landscaping • Potential for 52% reduction of peak flow from 1-year rain event Potential Rain Garden on Unquowa Place AREA E SOUTH OF RAILROAD TRACKS Description • Entirely impervious area south of Carter Henry Drive and north of Post Road Typical Land Uses • Commercial such as Pelo Hair Salon, Lion’s Paw & Company, 55 Wine Bar, Wood Grille Green Roof Benefits of Selected Green Infrastructure • Rain gardens collect stormwater, add natural spaces into an otherwise hardened area • Green roofs reduce runoff, “sustainable businesses” may attract visitors to retailers • Maintaining dry wells would alleviate flooding and could recharge the water table Underground Detention • Potential for 87% reduction of peak flow from 1-year rain event AREA F SOUTH OF RAILROAD TRACKS Description • Miller Street Typical Land Uses • Commercial Benefits of Selected Green Infrastructure Existing Sidewalk & On-Street Parking • Below ground detention chambers collect runoff, do not disrupt land use • Curb extension plantings act as rain gardens to infiltrate water • Extensions also put a safe distance between cars and pedestrians. LID Planter ‘Bump-outs’ and Permeable Paver Parallel Parking AREA G SOUTH OF RAILROAD TRACKS Description • Parcels on the east side of Miller Street Typical Land Uses Green Roofs • Commercial such as Colony Grill, Magic Beans Fairfield & Lansing Trade Group Benefits of Selected Green Infrastructure • Maintaining present drywells will prevent backup of stormwater • Installing green roofs will reduce runoff and improve water quality. • Potential for 87% reduction of peak flow from 1-year rain event Drywells AREA H SOUTH OF RAILROAD TRACKS Description • Parcels on the west side of Sanford Street Typical Land Uses • Commercial such as B. Good, Captain’s Pizza, and Fairfield Center Jewelers Parking on North Side of Post Road Benefits of Selected Green Infrastructure • Underground stormwater detention will not disrupt parking areas • Greens roofs cool buildings and reduce stormwater runoff • Installing GI planters along the Post Road provides infiltration • Potential for 8% reduction of peak flow from 1-year rain event Potential LID Planters Within Existing Non-used Space AREA I SOUTH OF RAILROAD TRACKS Description • Sanford Street Typical Land Uses • Commercial Benefits of Selected Green Infrastructure • Underground detention would alleviate runoff Permeable Pavers – On Street Parking • Curb extensions or GI planters would infiltrate stormwater and create consistency throughout the area • GI planters, installed with property owner assistance, retain runoff AREA J SOUTH OF RAILROAD TRACKS Description • Parcels between Sanford Street and Unquowa Road Typical Land Uses • Commercial such as the Warehouse at FTC, Old Post Tavern, and Archie Moore’s Benefits of Selected Green Infrastructure Existing Space West of Unquowa Road • The installation of drywells will capture stormwater within private parking areas • Green roof implementation on select roofs stores rainfall that contributes to flooding • A rain garden on the west side of Unquowa Place provides infiltration and a natural habitat between hardened areas • Potential for 64% reduction of peak flow from 1-year rain event Potential Rain Garden Between Bridge and Building AREA K SOUTH OF RAILROAD TRACKS Description • Sherman Green Typical Land Uses • Passive recreation Benefits of Selected Green Infrastructure Sherman Green • Shallow bedrock prevents underground detention • Installing infiltration gardens will catch and absorb stormwater • Will be an aesthetic feature on the town green Sherman Green Rain Garden • Signage would present an educational opportunity for this site, and sites throughout the area CONCLUSIONS CONCLUSIONS • Stormwater pipes that run north to south are potentially undersized • Soil and groundwater conditions are GI-friendly • Few GI best practices currently exist • GI will reduce runoff peak flows but will not completely offset challenges posed by undersized and limits stormwater infrastructure • GI will also reduce flooding volumes • GI will help address more intense precipitation that occurs over the coming decades • GI implementation would require retrofits and reconstruction • The Town should consider several amendments to Zoning Regulations, Subdivision Regulations, and Streetscaping/Roadway requirements