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Panther Hollow Watershed Healthy Yards Rain Garden Workshop

Schenley Park Visitor Center Pittsburgh, PA October 28th, 2010

SEEDS is a MI based 501(c)3 non-profit research, design and educational institution

Helping communities make appropriate decisions about built and natural infrastructure

Agenda • • • • • • •

What is a rain garden? How does it function? Primary components of rain gardens Basics of rain garden design Demonstration of rain garden sizing Breakout into design teams Present preliminary rain garden designs

What is a Rain Garden?

A Rain Garden Is Not a Water Garden


What is a Rain Garden?

Simple Rain Gardens

Complex Rain Gardens

How Does A Rain Garden Function?

Function: Hydrology

Function: Ecology

Anatomy of a Rain Garden

Components: Collection/Conveyance

Components: Pond/Bed/Berm

Components: Soil

Components: Inlet & Outlet

Components: Plants

How to Realize a Rain Garden • Defining Your Project Goals • Choosing a Location • Sizing a Rain Garden • Designing a Rain Garden • Installing a Rain Garden • Care & Maintenance

Define Your Project Goals • • • • • •

Watershed protection Local flooding issues Habitat creation Aesthetic planting Education Reducing watering needs • Getting rid of your lawn • Community Building

Choose Your Location Site Assessment – Take Notes & Create a Site Sketch • Impervious areas • Downspout locations • Natural grade • Flow paths • Sunny/shady areas • Existing trees & plantings • Low spots & wet spots • Soils and permeability

Choose Your Location Do • Select a flat to gently sloping area (12% or less) • Place at least 10 feet from a basement foundation wall • Call PA ONE CALL, dial 8-1-1 during design and 3 days before you dig & ID private underground utilities • Choose an area that rain overflow will drain away responsibly

Don’t • Place in a naturally wet area • Place on area of shallow bedrock • Place close to a large retaining wall or steep slope • Place over a drinking water well, septic tank, or leach field • Remove trees or significantly disturb tree roots to plant a rain garden

Sizing: 1. Determine Drainage Area Calculate the drainage area flowing to your rain garden location. • Determine roof sections draining to each downspout or drip line • Determine direction of flow over sidewalks, driveways, decks, etc.

Sizing: 1. Determine Drainage Area Calculate the drainage area flowing to your rain garden location.

Length (ft) x Width (ft) = Area (ft2) Area 1 + Area 2 + Area 3 + Area n = Area total

Sizing: 2. Determine Soils Determine soil suitability and type.

Sizing: 2. Determine Soils Simple Infiltration Test 1. Dig a 6� deep hole and fill with water 2. If water is still standing after 24 hrs, choose a new location

Sizing: 2. Determine Soils Identify Soil Type w/ Ribbon Test 1. Moisten a ball of soil in your hand 2. Push the ball between thumb and forefinger to form a ¼” ribbon of uniform thickness and width until the ribbon breaks. SAND – no ribbon SILT – weak ribbon <1.5” CLAY – ribbon >1.5”

Sizing: 3. Determine Slope

Sizing: 3. Determine Slope Select the appropriate depth

Sizing: 4. Calculate Size Select the appropriate sizing factor


400 ft2

100 ft2

Sizing: Other Sizing Considerations • Overland Flow – if rainwater flows over 30ft or more of lawn to the rain garden may reduce area by up to 50% • Soil Amendments – if clay soils are amended with significant sand, compost, and mulch may reduce area by up to 30%

Design: 1a. Determine the Shape â&#x20AC;˘ Approaches

Design: 1b. Determine the Profile â&#x20AC;˘ Approaches

Design: 2a. Design the Entrance

Design: 2b. Design Outlet/Overflow

Design: 2c. Other Features

Design: 3. Select Plants Criteria • perennial • water tolerant • drought tolerant • hardiness zone • shade/sun tolerance • nativity

Design: 4. Draw Final Design Sketch

Build: When to Start? • 3 Days after you call PA One Call: 8-1-1 • Best in spring or fall • After you’ve enlisted help or a small excavator • After you’ve ordered materials • After you’ve determined where to put the sod and extra soil • Not when the soil is wet

Build: 1. Define the Borders

Build: 2. Remove the Grass

Build: 3. Start Digging

Build: 4. Level the Bed

Build: 5. Improve the Soil

Build: 6. Plant

Build: 7. Mulch

Care & Maintenance Adaptive Management

Water – new plants regularly until roots are established especially if planted during summer Weed – weeding will be necessary in the first few years; pay particular attention to invasives Mulching – maintain/add mulch to cover exposed soil especially on berms Berms – rebuild/maintain berms so that overflows occur at the intended outlet

Sizing Demonstration

Useful Resources Kansas City Rain Garden Plant Database

Three Rivers Rain Garden Alliance

Vermont Rain Garden Manual

SEEDS Contact Information

Barton Kirk, EIT 802-238-0813 cell 412-363-2813 office

Panther Hollow Rain Garden Workshop, Spring 2011