Ponds and Stormwater in Prince William County: A Homeowners Perspective

Ponds and Stormwater in Ponds and Stormwater in Prince William County:Prince William County:

A Homeowners PerspectiveA Homeowners Perspective

Frank ReillyFrank Reilly

Why Me?Why Me?

• Army Engineers Waterways Army Engineers Waterways Experiment StationExperiment Station

• 10 Years of Wetlands Workshops10 Years of Wetlands Workshops– www.WetlandsWorkGroup.orgwww.WetlandsWorkGroup.org

• 10 Years as a Prince William Virginia 10 Years as a Prince William Virginia Cooperative Extension Master Cooperative Extension Master GardenerGardener– www.advancedmastergardener.orgwww.advancedmastergardener.org

ReviewReview

• PrecipitationPrecipitation

• RunoffRunoff

• InfiltrationInfiltration

• EvaporationEvaporation

What happens to the What happens to the Rain?Rain?

•Depends on many factors:Depends on many factors:•Rate of rainfallRate of rainfall•Soil conditions (Dry, Damp, Soil conditions (Dry, Damp,

Soggy)Soggy)•Density of vegetationDensity of vegetation•Amount of urbanizationAmount of urbanization•TopographyTopography

Natural ConditionsNatural Conditions

Developed ConditionsDeveloped Conditions

More impervious surface = more More impervious surface = more runoffrunoff

So What?So What?

• Degraded habitatDegraded habitat– bacteria, sediments, bacteria, sediments,

nutrients, and petroleum nutrients, and petroleum productsproducts

– Impaired watersheds Impaired watersheds

• Loss of habitatLoss of habitat– Silting in wetlandsSilting in wetlands– Destruction of SAVDestruction of SAV– Oyster reefOyster reef

• Increased regulationIncreased regulation– TMDLsTMDLs– Rain tax Rain tax

So what for me?So what for me?

• FloodingFlooding

So what for me?So what for me?

• FloodingFlooding

• Stormwater Stormwater maintenancemaintenance

So what for me?So what for me?

• FloodingFlooding

• Stormwater TaxStormwater Tax

• Personal damagesPersonal damages

Q

T

Developed Condition, Conventional CN(Higher Peak, More Volume, and Earlier Peak Time)

Existing Condition

HydrographHydrograph

Washington, DC - Reagan National

2001 Daily RainfallFrequency (inches)

90%

4%4% 2%

0.25

0.5

1

> 1

1 inch of rain falling on 1 acre 1 inch of rain falling on 1 acre = 27,154 gallons of water= 27,154 gallons of water

How can we make residential How can we make residential developmentsdevelopmentsfunction hydrologically like natural function hydrologically like natural systems?systems?

During A One Inch During A One Inch Rainstorm:Rainstorm:

• 25,800 gallons of water runs off a one-acre 25,800 gallons of water runs off a one-acre parking lot.parking lot.

• 1,361 gallons of water runs off a one-acre 1,361 gallons of water runs off a one-acre wooded area.wooded area.

Stormwater Management Stormwater Management Facilities (SWM)Facilities (SWM)

Underground FacilitiesUnderground Facilities

TrenchTrench

Wet Detention FacilitiesWet Detention Facilities

Dry Detention FacilitiesDry Detention FacilitiesBioretention (rain garden)Bioretention (rain garden)

Storm water FacilitiesStorm water FacilitiesPrince William County has record of:

•450 Commercial SWM/BMP facilities

•Wet ponds

•Dry ponds

•Sand filters

•Underground filters (Stormceptor, etc.)

•Other

Storm Drainage and Storm Drainage and Stormwater ManagementStormwater Management

• Storm Drainage SystemsStorm Drainage Systems– PipesPipes– InletsInlets

• Stormwater Management Stormwater Management Facilities (SWM) Facilities (SWM)

Dry Pond/ Wet PondsDry Pond/ Wet Ponds

Dry Pond FacilitiesDry Pond Facilities• Used in smaller drainage Used in smaller drainage

areasareas

• Smaller land area Smaller land area

• Less effective pollutant Less effective pollutant removalremoval

• Extended Detention (BMP)Extended Detention (BMP)48 – 72 hrs Detention48 – 72 hrs Detention

• Fencing/signage requiredFencing/signage required

• Easier maintenanceEasier maintenance

Dry Pond/ Wet PondsDry Pond/ Wet Ponds

Wet Pond FacilityWet Pond Facility• Larger drainage area Larger drainage area

• Permanent pool of waterPermanent pool of water

• Aesthetically pleasingAesthetically pleasing

• Water level rises with Water level rises with stormstorm

• Better sediment/ pollutant Better sediment/ pollutant removalremoval

• Signage requiredSignage required

• No fencing requiredNo fencing required

Property Owners Property Owners Maintenance ResponsibilitiesMaintenance Responsibilities

Long TermLong Term::• DredgingDredging• Structure repairs Structure repairs • Embankment Embankment

(compaction, seeps, (compaction, seeps, etc.)etc.)

• Major vegetation Major vegetation removalremoval

• Spillway Pipe/ Spillway Pipe/ Outfall ChannelOutfall Channel

• ErosionErosion

SafetySafetySafety - Water rises rapidlyFencing – Minimum 4 foot high chain link fenceGate - 15 foot wide gate with lock where the access road enters the facilitySignage – Warning signsAccess Road - VDOT standards •Access < 10% slope- 6” gravel•Access >10% slope -asphalt

Problem PreventionProblem Prevention

• Sediment/ Sediment/ Nutrient reductionNutrient reduction– Filter stripsFilter strips– Fertilizer reductionFertilizer reduction

• AerationAeration

• Trash removal Trash removal (debris rack)(debris rack)

• Woody vegetation Woody vegetation removal (periodicremoval (periodic) )

• Adjacent property Adjacent property impactimpact

Algae ProblemsAlgae Problems

• Excess nutrients Excess nutrients cause algae growthcause algae growth

• PreventionPrevention– Grass/vegetation Grass/vegetation

filter strips can filter filter strips can filter nutrientsnutrients

– Nutrient Nutrient Management (IPM)Management (IPM)

• RemovalRemoval– ChemicalChemical– MechanicalMechanical

Challenges of traditional stormwater Challenges of traditional stormwater management include:management include:

• Engineering, design and infrastructure can be Engineering, design and infrastructure can be more costly than mimicking natural systemsmore costly than mimicking natural systems

• Maintenance can be more expensiveMaintenance can be more expensive

• Significant space required for detention pondsSignificant space required for detention ponds

• Flow and volume of stormwater may not be Flow and volume of stormwater may not be adequately controlled, leading to:adequately controlled, leading to:– ErosionErosion– FloodingFlooding– Slope destabilizationSlope destabilization

So what is the problem?So what is the problem?As stormwater flows it picks up and As stormwater flows it picks up and transports:transports:

• SedimentSediment

• Pet wastePet waste

• SaltSalt

• PesticidesPesticides

• FertilizerFertilizer

• Oil and greaseOil and grease

• LitterLitter

• LeavesLeaves

• HeatHeat

SedimentsSediments•Soil particles Soil particles

carried by carried by rainwater into rainwater into streams, lakes, streams, lakes, rivers and baysrivers and bays

•By volume it is By volume it is the greatest the greatest pollutant.pollutant.

Nitrogen and PhosphorusNitrogen and Phosphorus

• SourcesSources– FertilizerFertilizer– Natural vegetationNatural vegetation– Animal wasteAnimal waste

• Promote algae Promote algae bloomsblooms

• Decaying algae Decaying algae depletes oxygen depletes oxygen levels in water. levels in water.

Litter & DebrisLitter & Debris

• Clogs BMP controlClogs BMP control• Can cause back-up of Can cause back-up of

water & dam deteriorationwater & dam deterioration• Degrades aesthetic Degrades aesthetic

qualitiesqualities• Decomposes slowlyDecomposes slowly• Physical danger to Physical danger to

vegetation and wildlifevegetation and wildlife

Litter and other potentially Litter and other potentially toxic & lethal substancestoxic & lethal substances

• Battery acid and Battery acid and antifreezeantifreeze

• Cleaning agentsCleaning agents

• Non-biodegradable Non-biodegradable packaging-packaging-Styrofoam, plastic Styrofoam, plastic bagsbags

• Cigarette buttsCigarette butts

LeavesLeaves• Decomposing leaves Decomposing leaves

deplete the oxygen deplete the oxygen in streams.in streams.

• If leaves build up in If leaves build up in underground catch underground catch basins, a poisonous basins, a poisonous gas (hydrogen gas (hydrogen sulfide) can occur. sulfide) can occur.

• Please do not blow Please do not blow or rake leaves or or rake leaves or grass clippings into grass clippings into the street! the street!

So what do we do?So what do we do?

•Remove Remove debris from debris from storm drains storm drains regularlyregularly

So what do we do?So what do we do?

• Clean parking lots Clean parking lots and paved areas of and paved areas of leaves, trash and leaves, trash and sediment.sediment.

• Sweep pavements-Sweep pavements-– And pick up the And pick up the

dirt-don’t sweep dirt-don’t sweep dirt into the gutter.dirt into the gutter.

So what do we do?So what do we do?• Reduce the Reduce the

amount of salt amount of salt used in parking used in parking lots and walkways lots and walkways

• AlternativesAlternatives– use ice melt, use ice melt,

sand, kitty litter, sand, kitty litter, cinders or ashescinders or ashes

So what do we do?So what do we do?

•Clear snow Clear snow from drainsfrom drains

•Clear snow Clear snow to the lower to the lower end of end of paved areas.paved areas.

So what do we do?So what do we do?

• Collect and Collect and recycle recycle hazardous waste hazardous waste oils, solvents oils, solvents etc.etc.

• Start a recycling Start a recycling program!program!

Low Impact Development Low Impact Development (LID)(LID)• Goal is to absorb stormwater naturallyGoal is to absorb stormwater naturally

Bioretention (rain garden)Bioretention (rain garden)

Green roofGreen roofGrass swaleGrass swale

Porous pavementPorous pavement

Rain BarrelRain Barrel

In The Landscape---In The Landscape---

• Fertilize cool season Fertilize cool season grasses in the fall not grasses in the fall not the spring. the spring.

• Use the right Use the right amount of fertilizeramount of fertilizer

• Leave the clippingsLeave the clippings

In The Landscape---In The Landscape---

• Do not apply Do not apply fertilizers or fertilizers or pesticides near pesticides near bodies of water, or bodies of water, or before a rain.before a rain.

• Sweep up any Sweep up any residue from hard residue from hard surfaces and surfaces and dispose of properly.dispose of properly.

Just a few reminders -Just a few reminders -

Partners For Water QualityPartners For Water QualityProgramProgram

•Call Cooperative ExtensionCall Cooperative Extension• Carol A McElroy Carol A McElroy

– 703-792-4037 703-792-4037 – [email protected]@pwcgov.org

– 10% rebate on current years 10% rebate on current years stormwater management feestormwater management fee

• Participating Participating inin– Adopt a Adopt a

stream orstream or– Adopt a spotAdopt a spot

Questions?Questions?

Prince William County Prince William County Watershed Management Watershed Management

Branch at (703) 792-7070Branch at (703) 792-7070

Environmental IssuesEnvironmental Issues

Resource Protection Areas (RPA)Wetlands

Stream RestorationWater Quality