Small Towns Sustainable Stormwater Solutions

Small Town Small Town Sustainable Sustainable StormwaterStormwater

SolutionsSolutions

Kathryn Hamilton, RLA, ASLAKathryn Hamilton, RLA, ASLAWestmoreland Conservation DistrictWestmoreland Conservation District

PA/DE ASLA Annual MeetingPA/DE ASLA Annual MeetingApril 8April 8--9, 20119, 2011

Urban, Industrial, Residential, AgriculturalUrban, Industrial, Residential, Agricultural

Flooding, Erosion, Pollution, DegradationFlooding, Erosion, Pollution, Degradation

The Natural The Natural WatercycleWatercycle

PrePre--Development: Development: illustrates the NATURAL hydrologic cycleillustrates the NATURAL hydrologic cycle

Post Development: Post Development: illustrates the IMPAIRED hydrologic cycleillustrates the IMPAIRED hydrologic cycle

StormwaterStormwater RetrofittingRetrofitting

A A StormwaterStormwater Retrofit Retrofit …… provides provides stormwaterstormwater treatment in locations where treatment in locations where practices previously did not exist or were practices previously did not exist or were ineffectiveineffective

Provides runoff capture and treatmentProvides runoff capture and treatment

Requires data collectionRequires data collection

Fingerprinted around existing elementsFingerprinted around existing elements

Public and private involvementPublic and private involvement

Why use Why use StormwaterStormwater Retrofits ?Retrofits ?

FloodingFlooding

FloodingFlooding

Stream degradationStream degradation

FloodingFlooding

Stream degradationStream degradation

Water quality issuesWater quality issues

Combined Sewer Combined Sewer Overflows (Overflows (CSOsCSOs))

RegulationsRegulations

Water PollutionWater Pollution

Costs $17 billion Costs $17 billion annually in the USAannually in the USA

Causes 14,000 deaths Causes 14,000 deaths worldwide each dayworldwide each day

Comes from the landComes from the land’’s s surface to create surface to create NonNon--Point SourcePoint Source and and Point SourcePoint Source PollutionPollution

NonNon--Point Source PollutionPoint Source Pollution

When rain falls on the When rain falls on the land, the runoff may land, the runoff may carry with it sediment, carry with it sediment, debris, chemicals, or debris, chemicals, or other pollutants. other pollutants.

Earth disturbance and Earth disturbance and land development are land development are big sources of big sources of NonNon--Point SourcePoint Source pollution.pollution.

Point Source PollutionPoint Source PollutionWater pollution might come from a single point source - as a pipe from a factory dumping pollutants into a river

ORCombined Sewer Overflow

Over 380 CSO Locations around Pittsburgh!Over 380 CSO Locations around Pittsburgh!

Sewage treatment agencies which Sewage treatment agencies which have CSO permits across PAhave CSO permits across PA

Changing Regulations!Changing Regulations!Why are we required to construct Why are we required to construct BMPBMP’’ss????

Regulations have been created to reverse the Regulations have been created to reverse the effects of effects of ‘‘dead zonesdead zones’’ developing in the developing in the Chesapeake Bay and Gulf of Mexico where Chesapeake Bay and Gulf of Mexico where much of the USAmuch of the USA’’s polluted s polluted stormwaterstormwater runoff runoff ends upends up

The new SWM regulations have the force of The new SWM regulations have the force of many environmental agencies behind them, many environmental agencies behind them, each with a different focus.each with a different focus.

Regulating Agencies !Regulating Agencies !

EPAEPA

DEPDEP

County Conservation DistrictsCounty Conservation Districts

PA Fish & Boat Commission PA Fish & Boat Commission

Army Corps of EngineersArmy Corps of Engineers

MunicipalitiesMunicipalities

PennDOTPennDOT

Utility consent order agreementsUtility consent order agreements

Regulations Provide GuidanceRegulations Provide Guidance

PA DEP regulates: PA DEP regulates:

Activities that might reduce water quality Activities that might reduce water quality including Land development including Land development

NPDES permits and Erosion + Sediment NPDES permits and Erosion + Sediment Control Permits both need Control Permits both need ““PostPost-- Construction Stormwater ManagementConstruction Stormwater Management”” (PCSM) plans and BMP(PCSM) plans and BMP’’s. s.

PA PA StormwaterStormwater BMP Manual (DEP 2006)BMP Manual (DEP 2006)

ObjectivesObjectives

Fix past mistakes & Fix past mistakes & maintenance maintenance problemsproblems

Solve chronic flooding Solve chronic flooding problemsproblems

StormwaterStormwater demonstration & demonstration & educationeducation

Objectives (cont.)Objectives (cont.)

Pollutant removalPollutant removal

Reduce runoff Reduce runoff volumesvolumes

Stream Stream corridor/watershed corridor/watershed restorationrestoration

98% of Rainfall Events are less than 1 inch98% of Rainfall Events are less than 1 inch

Rainfall and RetrofitsRainfall and Retrofits

BMPsBMPs designed to treat 1designed to treat 1”” rainfallrainfall

Mount Pleasant Mount Pleasant Residential Residential

Rain Gardens Rain Gardens stormwaterstormwater retrofitretrofit

Mount Pleasant PAMount Pleasant PASpring 2010Spring 2010

Project Partners:Project Partners:Westmoreland Conservation DistrictWestmoreland Conservation District

Mount Pleasant BoroughMount Pleasant BoroughResidents of Mount Pleasant Residents of Mount Pleasant

PA Department of Environmental ProtectionPA Department of Environmental Protection

Typical rain garden scenarios were presented to the Typical rain garden scenarios were presented to the homeowners, to encourage them to participatehomeowners, to encourage them to participate

Possible Rain Garden Locations for Roof WaterTreatment

FLOW OF RUNOFF

DOWNSPOUT

DOWNSPOUT

WCD staff and interns surveyed and evaluated the property WCD staff and interns surveyed and evaluated the property of each interested homeownerof each interested homeowner

PA OnePA One--Call for Design and LayoutCall for Design and Layout

Current Downspout Outlet

Homeowners were Homeowners were given choices of given choices of

rain garden rain garden planting schemes planting schemes as well as specific as well as specific

plants for their plants for their gardensgardens

Each homeowner had to sign a Each homeowner had to sign a ‘‘RAIN GARDEN RAIN GARDEN

RIGHTRIGHT--OFOF--WAY AND EASEMENT AGREEMENTWAY AND EASEMENT AGREEMENT’’

Whereas the Grantor owns a certain tract of landWhereas the Grantor owns a certain tract of land……

Whereas the Grantee received a grant for design, Whereas the Grantee received a grant for design, construction and installation of a rain gardenconstruction and installation of a rain garden……

Whereas the Grantor desires to be a steward of the Whereas the Grantor desires to be a steward of the land and participateland and participate……

Whereas the Grantee requires certain easements Whereas the Grantee requires certain easements and rightsand rights--ofof--way to enable constructionway to enable construction……

Whereas Grantor desires to grant and convey to Whereas Grantor desires to grant and convey to Grantee the easement and rightGrantee the easement and right--ofof--wayway……

RAIN GARDENRAIN GARDEN RIGHTRIGHT--OFOF--WAY AND EASEMENT AGREEMENTWAY AND EASEMENT AGREEMENT

Grantee shall construct in good and safe Grantee shall construct in good and safe condition said rain garden and condition said rain garden and appurtanancesappurtanances……

Grantor, its agents, successors and Grantor, its agents, successors and assigns agrees to the sole responsibility of assigns agrees to the sole responsibility of the maintenance of the rain garden after the maintenance of the rain garden after construction construction ……for a period of 20 years for a period of 20 years ……

Each rain garden was marked and approved prior to diggingEach rain garden was marked and approved prior to digging

Excavation was done carefully to avoid utilities, protect Excavation was done carefully to avoid utilities, protect existing features and minimize disturbanceexisting features and minimize disturbance

Each rain garden excavation was checked for proper depth Each rain garden excavation was checked for proper depth to meet design requirementsto meet design requirements

The Contractor was able to minimize disturbance on each The Contractor was able to minimize disturbance on each property and minimize inconvenience to neighborsproperty and minimize inconvenience to neighbors

An An underdrainunderdrain layer included a perforated pipe surrounded layer included a perforated pipe surrounded by clean stone and a by clean stone and a geotextilegeotextile wrapwrap

A soil mix of 50% topsoil, 30% sand, 20% compost was A soil mix of 50% topsoil, 30% sand, 20% compost was placed 18placed 18”” to 24to 24”” deepdeep

Finished grade of the soil mix was checked to ensure Finished grade of the soil mix was checked to ensure sufficient surface sufficient surface pondingponding depthdepth

A riser pipe is yet to be cutoff to protect soil and mulch from A riser pipe is yet to be cutoff to protect soil and mulch from entering the entering the underdrainunderdrain during constructionduring construction

Completed rain garden: rock dissipater at downspout, Completed rain garden: rock dissipater at downspout, landscaping with mulch, basket grate overflow riserlandscaping with mulch, basket grate overflow riser

Each Each underdrainunderdrain outlets safely to the street gutter or to the outlets safely to the street gutter or to the municipal storm systemmunicipal storm system

The location of each rain garden was approved by the The location of each rain garden was approved by the homeowner and designed to capture roof waterhomeowner and designed to capture roof water

ScottdaleScottdale Library Plaza Library Plaza

stormwaterstormwater rain gardenrain garden

ScottdaleScottdale PAPAFall 2009Fall 2009

Project Partners:Project Partners:Westmoreland Conservation DistrictWestmoreland Conservation District

ScottdaleScottdale LibraryLibraryScottdaleScottdale BoroughBorough

PA Department of Environmental ProtectionPA Department of Environmental Protection

An abandoned street stub provides an opportunity for a stormwater management retrofit utilizing an existing inlet and rooftop runoff

Scottdale’s 100 year old street was layers of asphalt, 3 inch brick, 4 inch slag bed and 8 inch poured concrete

The rain garden area is excavated to expose the inlet and to provide enough volume for the infiltration layers

The rain garden is constructed using the existing street inlet as an emergency overflow

A standard concrete curb separates the porous concrete edge from the rain garden soil mix

Completed stormwater plaza includes the rain garden, porous concrete and a raised planter

Rainwater drains through the porous concrete into a stone base

Native plants help with evapotranspiration of stormwater from porous concrete and a rain garden

Mount Pleasant Mount Pleasant Parking Lot Rain Parking Lot Rain

Gardens Gardens stormwaterstormwater retrofitretrofit

Mount Pleasant PAMount Pleasant PASpring 2010Spring 2010

Project Partners:Project Partners:Westmoreland Conservation DistrictWestmoreland Conservation District

Mount Pleasant BoroughMount Pleasant BoroughMount Pleasant Parking AuthorityMount Pleasant Parking Authority

PA Department of Environmental ProtectionPA Department of Environmental Protection

Mount Pleasant Borough parking lots generated stormwater which ran uncontrolled into the streets, flooding downhill neighbors

Five rain garden locations were excavated at the low point in each parking lot

Each rain garden has an underdrain layer which includes a perforated pipe and clean stone wrapped in fabric

Each rain garden has a rain garden soil mix and an overflow riser connected to the underdrain

The rain gardens are landscaped with native plants, mulch and stone to slow and infiltrate runoff

Rain water rushes into the rain garden through curb cuts and onto rock energy dissipaters

An unsightly paved island with crumbling curbs increased runoff and provided little aesthetic value

The paved and curbed island was replaced with porous concrete and trees in over-excavated tree planting pits

Columbia Columbia Avenue Tree Avenue Tree

Planting Planting using Silva Cellsusing Silva Cells

Vandergrift PAVandergrift PASpring 2010Spring 2010

Project Partners:Project Partners:Westmoreland Conservation DistrictWestmoreland Conservation District

Vandergrift BoroughVandergrift BoroughVandergrift Improvement ProgramVandergrift Improvement Program

PA Department of Environmental ProtectionPA Department of Environmental Protection

The historic Borough of Vandergrift has wide sidewalks and many street trees, just not in this location

A ‘green’ plan for managing urban stormwater runoff was designed to go under the wide sidewalks, to be soaked up by trees

‘Silva Cell’ soil containment system is filled with a loose soil mix for stormwater retention

‘Silva Cells’ supports pavements while protecting soil from compaction for better tree health

Porous concrete was placed over the ‘Silva Cells’ on a bed of crushed stone, leaving holes for planted trees

Porous concrete is placed over ‘Silva Cells’ and trees are planted in the un-compacted soil

Greensburg Greensburg Parking Lots Parking Lots

stormwaterstormwater management retrofitmanagement retrofit

Greensburg PAGreensburg PASpring 2007Spring 2007

Project Partners:Project Partners:Westmoreland Conservation DistrictWestmoreland Conservation District

City of GreensburgCity of GreensburgGibson Thomas EngineersGibson Thomas Engineers

PA Department of Environmental ProtectionPA Department of Environmental Protection

An abandoned transmission shop, dilapidated properties and alleyways were demolished by the City to make way for a city parking lot

Moore Avenue Lot

A ‘green’ plan for the new parking area included infiltration islands and canopy trees to reduce stormwater runoff to the combined sewer

Once fully covered with impervious surfaces, this area is now partially green and manages stormwater

Wheelstops in the parking area delineate leased spaces and allow runoff to be captured by the grass lined infiltration swales

2B STONE BACKFILL2B STONE

BACKFILL

The City demolished residential properties (some dilapidated) to make way for a city parking lot

A ‘green’ plan for the new parking area included a rain garden, porous paving, canopy trees, and underground infiltration chambers

Stormwater runs off a portion of the parking area and is captured by a landscaped rain garden

Stormwater runs off the parking area below the rain garden and is captured by a porous concrete paver unit system

EconomicsEconomicsMt Pleasant Parking Lot Mt Pleasant Parking Lot

Rain GardensRain Gardens

1,500 1,500 sfsf in (5) rain gardensin (5) rain gardens

1,300 1,300 sfsf porous concreteporous concrete

4,500 4,500 cfcf runoff capturerunoff capture

Bid price: $75,000Bid price: $75,000

Average cost commercial Average cost commercial rain gardens*: $20rain gardens*: $20--$30 / $30 / sfsf

Average cost porous Average cost porous concrete*: $12 / concrete*: $12 / sfsf

*NOTE: costs include demolition and site *NOTE: costs include demolition and site preparationpreparation

EconomicsEconomicsMount Pleasant Residential Mount Pleasant Residential

Rain Garden projectRain Garden project

100 100 sfsf to 200 to 200 sfsf rain rain gardens in 14 locationsgardens in 14 locations

1,800 1,800 cfcf runoff capturerunoff capture

Bid price: $55,000Bid price: $55,000

Average rain garden cost*: Average rain garden cost*: $25$25--$35 / $35 / sfsf

*NOTE: costs include site preparation*NOTE: costs include site preparation

EconomicsEconomicsScottdaleScottdale Library Library

StormwaterStormwater PlazaPlaza

300 300 sfsf rain gardenrain garden

960 960 sfsf porous concreteporous concrete

850 850 cfcf runoff capturerunoff capture

Bid price: $54,600Bid price: $54,600

Average rain garden Average rain garden cost*: $30 / cost*: $30 / sfsf

Average porous concrete Average porous concrete cost*: $22 / cost*: $22 / sfsf

*NOTE: costs include demolition and site preparation*NOTE: costs include demolition and site preparation

EconomicsEconomicsVandergriftVandergrift’’s Columbia Ave s Columbia Ave

street tree plantingstreet tree planting

6 canopy trees6 canopy trees

1,200 1,200 sfsf porous concreteporous concrete

2,200 2,200 cfcf structural infiltration structural infiltration soil support systemsoil support system

650 650 cfcf runoff capturerunoff capture

Project Bid: $75,000Project Bid: $75,000

Average structural soil system Average structural soil system cost*: $65 / cost*: $65 / cfcf

Average porous concrete Average porous concrete cost*: $10 / cost*: $10 / sfsf

*NOTE: costs include demolition and site *NOTE: costs include demolition and site preparationpreparation

EconomicsEconomicsGreensburg City Parking Greensburg City Parking

Lot infiltration islandsLot infiltration islands

530 lf infiltration trench530 lf infiltration trench

4,700 4,700 sfsf infiltration infiltration paverpaver blocksblocks

6,000 6,000 cfcf runoff capturerunoff capture

Bid cost: $1.5 MBid cost: $1.5 M

Average infiltration bed Average infiltration bed cost*: $80 cost*: $80 -- $100 / lf$100 / lf

Average infiltration Average infiltration paverpaver cost*: $7 / cost*: $7 / sfsf

**NOTE: costs DO NOT include demolition and NOTE: costs DO NOT include demolition and site preparationsite preparation

References:References:

Pennsylvania Pennsylvania StormwaterStormwater Best Management Best Management Practices Manual 2006Practices Manual 2006

Provides guidance on the design and installation of Provides guidance on the design and installation of stormwaterstormwater best management practices and post construction best management practices and post construction stormwaterstormwater management plans for NPDES permitsmanagement plans for NPDES permits

www.depweb.state.pa.uswww.depweb.state.pa.us

Center for Watershed ProtectionCenter for Watershed Protection’’s Urban s Urban SubwatershedSubwatershed Restoration Series Restoration Series -- Manual 3: Manual 3: Urban Urban StormwaterStormwater Retrofit PracticesRetrofit Practices

www.cwp.orgwww.cwp.org

Questions?Questions?

Contact: Kathryn Hamilton, RLA, ASLAContact: Kathryn Hamilton, RLA, ASLAkathyh@wcdpa.comkathyh@wcdpa.com

218 Donohoe

RoadGreensburg PA 15601724-837-5271www.wcdpa.com