Homeowners Guide to

Stormwater Management

Dana RizzoExtension Educator, Water Quality

Penn State Extension &

Westmoreland Conservation District

Outline

Watersheds

What’s in the Water: Pollutants and Water Quality

Rainwater: Liability or Asset on a Site?

Site Management Maintenance

Grading

Best Management Practices Landscaping

Rain Barrels

Rain Gardens

Porous Pavements

Green Roof

What Is a Watershed?A watershed is the area of land that drains to a

particular point (stream, pond, lake, ocean)

Watersheds

A watershed’s shape is determined by the

surrounding terrain that forms its boundaries.

Watersheds PA has 6 major watersheds & every watershed is

unique.

Forested vs Urban Watersheds

Forested

Mostly covered by trees

Most rain is quickly absorbed by soil

Tree roots hold soil in place and allow the soil to filter the rainwater

Leaf litter cushions rain and prevents water from loosening and moving soil to stream.

Forested vs Urban Watersheds

Urban Mostly covered by

pavement

Most rain runs off streets into storm drains and flows directly into streams

Less vegetation allows for faster moving water

Little to no cushion to prevent rainwater from loosening and moving soil to stream

Annual hydrologic cycle for undisturbed acreagein Westmoreland County

Annual hydrologic cycle for developed acreagein Westmoreland County

What’s in the Water?

Stormwater collects and

transports pollution.

Soil

Pet waste

Herbicides and pesticides

Fertilizer

Salts

Heavy metals

Petroleum products

Rainwater: Liability or Asset?

Liability

Wet basement

Springs in unfortunate

areas

Wet/swampy spots

Damaged landscaping

Winter ice

Mosquito problem

Asset

Green lawns

Healthy landscapes

Visual amenity

Recreation

Drinking water

Wildlife habitat

Where does site water come from?

Roofs (downspouts)

Paving (driveways,

streets, patios)

Subdrains, foundation

drains

Springs, seeps

Off-site, uphill

Where does site water go?

Laying in wetspots

Laying against

foundations

Landscape

Inlets, storm pipes

Street

Off-site, downhill

The Big Picture

If a homesite is part of a

large development there

may already be a

neighborhood

stormwater management

plan in place which

could include:

Swales (grassy channels)

Inlets

Detention basin

Red Flags

Swales dry or filled in with soil or debris

Inlets dry or clogged with trash or debris

Flows diverted by obstructions

Basin has too much or no water after a rain

event

Outlet structure not functioning properly

Swales, inlets not functioning properly

Awareness

Be aware of any

existing controls and if

they are functioning

properly

Inform owner,

municipal maintenance

or homeowner’s

association of any

maintenance needs

What is your site like?

Slopes

Soils

Surface water

Vegetation

Underground utilities

Paved surfaces

Roof drainage

Basement

Soils

Western PA soils

generally have a high

clay content which traps

water near the surface

and reduces the soil’s

capacity for infiltrating

water

Surface Water

Many surface waters are

endangered by lack of

streambank protection

(vegetation) and

excessive stormwater

runoff from developed

areas

Vegetation

Short mowed lawns and

a lack of shade trees,

shrubs and perennials

can cause the ground to

erode or even to harden

and crack, limiting its

ability to soak up water

Underground Utilities

Underground septic

systems, water wells, or

utility lines may get in

the way of certain uses

Underground systems

should be protected

from harm

Paved Surfaces

Paved surfaces, even a

gravel surface choked

with mud, can produce

excessive water runoff

Roof Drainage

Downspouts collect roof

water, but concentrate

the flow which can

damage landscapes and

create undesirable wet

spots

Basement

Water can seep into

basements from poorly

maintained downspouts,

springs, and surface

water which can lay

against the foundation

wall

Problem Spots

Gutters, Downspouts

Subdrains

Low spots

Steep slopes

Seeps, springs

Bare earth

Paved areas

Other

Managing Water On-site

Maintenance

Grading

Best Management

Practices

Landscaping

Rain barrel / cistern

Rain garden

Porous paving

Green roof

Maintenance

Gutters

Downspouts

Subdrains

Swales

Inlets

Pipes

Grading

Avoid steep slopes

Direct water away from

foundation

Protect window wells

Landscaping

Utilizing size, shape, color, texture, and

growth requirements:

Enhance views

Accentuate structures

Define spaces

Attract wildlife

Control climate

Manage stormwater

Landscape Solutions

Leaves, needles, twigs, branches, trunks, bark

all catch, entrap, hold and filter precipitation

before it ever reaches the ground

Healthy plants lead to healthy soils which can

infiltrate water

Evapotranspiration of water from the soil to

the air completes the natural water cycle

Lawn

Healthy lawns – set

mower high to choke

out weeds and shade

soil

Vegetation

Variety of shrubs

and perennials –

natives have

extensive root

systems for water

absorption and

provide food and

habitat for wildlife

Stormwater Functions

Shade trees have an

extensive root system

for healthier soils and

water absorption and the

shade they provide

protects the soil from

drying out

Stormwater Functions

Use Native Plants

Capture runoff

Require less maintenance

Enrich soil

Provide biodiversity

Rain Barrel / Cistern

A rain barrel is a collection system that stores roof top runoff to be used later

Watering lawn & garden

Washing cars

Overflow to garden

Can be installed in series

Rain Barrel Anatomy

A – hole in top for downspout connection, metal screen for mosquitoes

B – hole on side near top for overflow hose

C – hole on side near bottom for hose bib

D – blocks to elevate barrel

D

A

B

C

Rain Barrel Installation

Rain Barrel Installation

How Much Water on your roof?

To estimate the runoff from a roof:

Multiply the roof’s length x width = square feet

Multiply sq. ft. x 0.6 x rainfall in inches = gallons

(0.6 is a conversion factor)

For example, if your roof is 28’ x 40’ = 1120 sq. ft, and you have a 1/4 inch rainstorm:

Rain caught (in gallons) = 1120 sq. ft. x 0.6 x .25 inches = 168 gallons

Worried about

Mosquitoes?

Mosquito Life Cycle

Property Patrol

Rain Garden

Capture first 1 inch of rainfall

Utilizes a plant bed to infiltrate water into the ground

Can be used in series with rain barrels to treat overflow

Can become a focal point in a landscape

Rain Garden Anatomy

Ponding Zone

Retention/filtration Zone

Retention/recharge Zone

6”to 12”

18”to 36”

6”to 12”

Rain Garden Function

Gently sloping site downhill from a downspout

Blend in with other garden features

At least 10 feet away from the house so infiltrating

water doesn’t seep into the foundation

Do not place a rain garden over a septic system

Full or partial sun is best, not under a large tree

Don’t put it where water already ponds (It is meant to

encourage infiltration; a wet patch shows where infiltration is slow)

Rain Garden Location

Rain Garden Plants

Mix of trees, shrubs and

perennials

Growth requirements

matching:

Garden size

Tolerant of sun exposure

Tolerant of moist to wet

soils

Tolerant of drought

conditions

Seasonal interest

Spring

Photo courtesy of Barr Engineering, Burnsville, MN

Summer

Photo courtesy of Barr Engineering, Burnsville, MN

Questions ?