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RAINSCAPES ENVIRONMENTAL SITE DESIGN WORKSHOP

MONTGOMERY COUNTY,  MD DEPARTMENT OF ENVIRONMENTAL PROTECTION WATERSHED MANAGEMENT DIVISION RAINSCAPES PROGRAM

JANUARY 18, 2017

HOMER S. GUDELSKY INSTITUTE FOR TECHNICAL EDUCATIONROCKVILLE, MD

RAINSCAPES.ORG

AgendaAgenda

Core Concepts of Environmental Site Design (ESD)

Stormwater, our Watershed and the MS4 Permit

Site Assessments for ESD

Rain Gardens and Conservation Landscapes: Design, Construction and Examples

Rebate Program

Questions

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CORE CONCEPTS OF ESD

Small scale vegetative practices integrated throughout the site, as close to the source as possible, to mimic pre-construction and natural hydrology

RAINSCAPES = LID = ESD = GREEN INFRASTRUCTURE

Old Approach to StormwaterManagement

Catch water at the bottom of the hill, concentrates water flow and pollution

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1. Healthy Soils and Native Plant Benefits • Organic matter increases

infiltration rate• Native plant roots open

up soil drainage structure

2. Decentralized Small Scale Design Approach• Slow it down, spread it

out and soak it in

3. Treatment Train Approach• Using multiple practices

together to manage stormwater

Core Concepts of Environmental Site Design

Infiltration!Soil is Mother Nature’s Filter

•The minerals in soil act as a filter.

•Soil is full of carbon from decaying plantsand animals. Carbon is a great filter.

•Healthy soil is full of micro organismsthat can help break down pollutantssuch as pesticides and petro-chems.

• Healthy de-compacted soilsinfiltrate stormwater faster

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Value of Using Native Plants

•Deeper roots – absorb more water and aids in soil de-compaction

•Use no fertilizer

•Use little or no pesticides

•Do not require watering after establishment

Why we care about roots!

Root systems play a large part in rainwater infiltration.

They store more water and create avenues for water to drain deeply into the soil.

(Courtesy of Mid-America Regional Council)

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Carex muskingumensisLobelia cardinalis

Provide Wildlife Habitat

Birds

Butterflies

Bees

Aesclepias tuberosaButterfly Weed

Cephalanthus occidentalisButton Bush

Ilex verticillataWinterberry

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Stormwater, Our Watershed and MS4

StormwaterRunoff

Rainwater that flows off impervious surfaces such as rooftops, driveways, roads and sidewalks picks up pollutants on the way, including chemicals from our lawns.

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What is in stormwater runoff?

Volume and velocity impacts!

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We cannot do this anymore….because it is damaging our watershed

An area of land that drains its stormwater into a body of water.

What is a watershed?

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Example Subcatchments

(aka drainage areas)

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There are over 1,500 miles of streams in Montgomery 

County

Montgomery County

This is the Chesapeake Bay watershed

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1972

Clean Water Act

NPDES (National Pollutant Discharge Elimination System) 

Permit Program

1987

MS4 (Municipal Separate Storm Sewer System)  Permit 

Program

Expanded Point Source discharge pollutant measures to require municipalities to get permits for stormwater runoff 

discharge

2007

Maryland Stormwater Act 

effective May 2010 

Maryland StormwaterDesign Manual included a 

new Chapter 5

requires environmental site design to the maximum extent 

practicable

“ESD to the MEP”

Montgomery County

NPDES MS4

Permit =

Stormwater Discharge Permit

2010‐2015

Federal CountyState

What are we facing?

• Rain events have increased in intensity and may be changing drainage patterns

• Communities and homeowners confronted with large volumes of water from lot to lot drainage

What are you facing?

….Assessing a site for ESD

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Assessing Sites for ESD

Single FamilyMulti Family

Institutional/Pools

Some initial things to consider…

Identify Any Legal Requirements

• Home Owner Association Rules

• Local Ordinances

• Right-of-Way and Easement Locations

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Site Assessment Forms

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Step 1 continued

• What are you trying to accomplish? = Client Interview

• Solving an existing flooding / erosion problem = Solution can be involved ($$$) to handle the water that is coming through

• Preventing pollution = Solution can be more straightforward

…or combine both

• Where is the water coming from?

• Property owner’s downspouts,

• uphill neighbor’s roof, • or both?

• How much water? How fast?

Steps to a RainScapes Site AssessmentStep 2

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Single Family Home

Are you looking at somethinglike this?

Or something like this? Homeowner roof and lot to lot drainage

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Steps to a RainScapes Site AssessmentStep 3Identify impervious surfaces and note direction of flow

Single Family Home

LOOK FOR SINGLE SOURCE OPPORTUNITIES

Multi-Family

Do the downspouts drain on gradeor are they piped underground?

Where do they daylight?

Are they functioning/clogged?

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LOOK FOR MULTI-SOURCE OPPORTUNITIES

Multi-Family

Project determination

• Is the water draining to open lawn areas or heavily treed areas?

• What is the slope of the property?

Open lawn space and more level sites = Rain Gardens (no utilities and must pass a perc test)

Heavily treed lots and steeper grades = Conservation Landscape

Lots of pavement = Permeable pavers

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Residential Rain Garden

Water flow

Possible Rain Garden

- Change landscape practice: have plantingsextend to bed edge instead of trench, usegroundcover such as sedum ternatum, heuchera, tiarella.

Must pass a perc test- Call Miss Utility- No tree roots impacted

RAIN GARDEN = open lawn areas

Must pass a perc test

Call Miss Utility

No tree roots impacted

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Permeable paver retrofit project.Rebate requires certified contractorthrough Interlocking Concrete Paver Institute (ICPI) specializing in PICP.

(Permeable interlocking concrete pavers)

Rain garden project

Direct downspout water runoff to rain garden. Size for the amount of roof or other impervious surface runoff the rain garden is handling.

Possible Rain Garden

Permeable Pavers

Permeable Pavers

PossiblePermeable Pavers

This house is at thebottom of the hill

A LOT OF WATER COMING IN AND NOT MUCH SPACE TO DEAL WITH IT

Rain Garden Rules: Fence lines and foundations 10’ away

Except…

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Conservation Landscapes for steep slopes and sites with

slopes and trees need Check Dams

Series of swooping stone check dams with small boulders and cobble slow and spread water flow into new plantings betweenthe check dams

Lots of paved surface & not much green space = Permeable Paver Retrofit

MUST BE PICP CERTIFIED THROUGH ICPI

(interlocking concrete paver institute)

Creating “Green Islands” in your parking lot

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TREATMENT TRAIN = COMBINING 2 OR MORE ESD PRACTICES ON ONE SITE

Church Property HOA Property

Commercial / Institutional Scale Site Assessment

Check dams

PUTTING IT ALLTOGETHER

Residential Treatment Train….

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SHEET FLOW OFF PARKING AREA

TREATMENT TRAINS

INSTITUTIONAL/POOLS=

LARGE PARKING LOTS

Overflow directthrough garden

AFTER THE SITE ASSESSMENT…

WHAT NEXT?

perhaps you want to do a rain garden…

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First do a perc test…butCall before you dig!

Miss Utility811

national call before you dig line

http://www.call811.com/

PERC TEST STEP 1:

To find out how fast your soil drains, do a perc test.

Break up the soil with a digging bar.

STEP 2:

Remove the soil with a post hole digger.

Use a trash bag to contain the soil.

STEP 3:

Dig a 2 foot deep by 1 foot wide hole OR

Dig as deep as you will excavate.

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STEP 4:

Fill hole to the top with water.

Record the time when hole is filled.

STEP 5:

Cover the hole for safety purposes.

STEP 6:

Check the hole and record how long it took to empty.If hole drained in less than 36 hours, repeat steps 1-5 in same hole.

•Site did not pass a perc test•Underground utilities running through the site•No place to overflow•Too steep

DESIGN A CONSERVATION LANDSCAPE•Minimum of 250 sq. ft./ 350 sq. ft. commercial, multifamily

•Replacing existing turf, invasive plants or solving an erosion problem

•Must have an impervious surface draining to the site

•75% natives, cultivars OK

Perc test passed!!! OK FOR DESIGNING A RAIN GARDEN

Perc test failed!!! 

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RAIN GARDENS AND CONSERVATION LANDSCAPE DESIGN AND CONSTRUCTION

Sizing your Rain Garden and Conservation Landscape:

Measure your roof /drive area

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Sizing Chart Calibrated for Montgomery County, MD

• Assumes 6” of ponding, SF is media footprint

• ‘1 foot planting bed’ refers to planting media depth

• The numbers in the colored area indicate inches of rain captured/ treated/ stored in a 24 hour time period

• Double the media footprint when using this chart to size you Conservation Landscape

• Need to treat at least 1.2 inches of rain

• We would request at least 2 given our recent

• rain events

Ponding vs. Soil Media Footprint

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INSTALLING RAIN GARDENS

Soil Replacementvs.

Soil Amended

THE WATERFORD EXPERIMENT

Soil ReplacementRain Garden

VSSoil Amended Rain Garden

175 sf media foot print, IA=780 sf12” planting depth, 3” mulch layer, 6” ponding

290 sq ft media foot print, IA= 2580 sf12” planting depth, 3” mulch layer, 6” ponding

Both sites passed a perc test, drained within 24 hours/2 fills

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Hauled 2 truck loads of soil away4 hours to get ready for planting

Excavated 21”Hauled soil away

21” excavation=

12” planting depth 3”mulch layer 6”ponding depth

SOIL REPLACEMENT RAIN GARDEN

SOIL AMENDED RAIN GARDEN

No soil hauled away,2 hours to get ready for planting

9” excavation=

3” mulch layer 6”ponding depth

12” planting depthTilled in 2” compost

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THE WATERFORD EXPERIMENTFIRST RAIN EVENT AFTER INSTALLATION

SOIL REPLACEMENT COMPOST AMENDEDVS

AFTER ONE YEARCompost amended garden

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Soil replacement garden

AFTER ONE YEAR

Rain Gardens

xcavate 11”6” PONDING3” MULCH

2” COMPOST

12” DEEP COMPOST AMENDED

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Drain pipe

Swale

Splash blocks

Downspout

Berm

Gutters

Rain Gardens

Bottom of pipe should be above the max ponding depth!!!!

You may need to move the down spout water to the rain garden.

Must be 75% native plants, cultivars OK!

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Using Trench Drains, Dry Stream Beds and Linear Dry Wells to Direct the Water Flow

Must stabilize berm slopes, this is a little steep

With lot to lot drainage,should oversize your rain garden

Sheet flow

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Area is too steep for a rain garden,

Best practice is

CONSERVATION LANDSCAPE WITH

CHECK DAMS

Planting in swales =be careful, how much water is coming through and how fast?

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Check Dams-How big, how many and how far apart?

Slope/Velocity, VolumeAsthetics

RAIN GARDEN PLANTER

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Rain Garden Planter

Before After

Before After

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Plant by Moisture Type in Rain Gardens:Right Plant in the Right Place

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MATURE

SIZE

MATTERS

PLANT

PLANTING FOR EASY MAINTENANCE!

• Fewer varieties in larger groupings

• Mature size matters

• Clump grower vs “Naturalizer”

• Start with the appropriate container size for the project

Have a hand watering schedule for 6 weeks3x a week for 2 weeks2x a week for 2 weeks1x a week for 2 weeks

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Important to space ground cover layer plants to fill in

within a year without overgrowing the space

Do native cultivars have the same benefits for pollinators as straight species? It depends

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Graphics from Designing with Natives by JRogers

Runoff control and so much more

Graphic from Designing with Natives by JRogers

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Other benefits to the environment

Plant selections based on plant communities

Try to create or emulate a specific habitat, like woods, wetland, or meadow

Physical/ aesthetic layout based on client’s style preferences

Upland meadow species

Wet meadow/ woods edge species

Wet meadow/ stream edge species

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EXAMPLES

Conservation Landscape in a swale

Water flow

Rain Garden overflow to Conservation Landscape

Rain Garden

Berm

Conservation Landscape

Water flow

(40)

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Water Flow

Treatment Train =

stone check dams, planted dry stream to 2 tier Rain Garden

Eastern Red Cedar

Blue Eyed Grass

Penstemon Husker Red

Dwarf Crested Iris

River Birch

False Blue Indigo

Aster ‘Alert

Creeping Phlox

Dry Well

In tune with residential aestheti

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Front yard conversion torain garden and conservation landscape

Congregational site

Before After

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Treatment trainCaptures drainage from 3 lots

Very compacted turf

Conservation landscape and dry wells plus underdrainedrain garden above

Front Yard as Front Porch: Transformation

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Excessive road drainage = large dry well with CL

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REBATE PROGRAM

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RainScapes Techniques in Action

RainScapes RewardsIncentive Program

Rebates for single family residences: $2,500 per property with lifetime project caps

Rebates for multi-family/commercial / institutional:$10,000 per propertywith lifetime project caps

All County property owners outside of municipalities Rockville, Gaithersburg and Takoma Park are eligible for rebates

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Rewards Rebate Program: Rain Gardens

• Residential: $1,200 per garden or a square foot amount based on soil depth , which ever is greater

• Commercial : $2,500 per garden or a square foot amount based on soil depth, which ever is greater

Sized for 1.2” rainfall volume minimum

75% plants must be native

Site must pass a perc test

Rewards Rebate Program: Conservation Landscaping

• $2.00-$3.00 per square foot/microberms

• Minimum 250 square foot conversion of turf area or invasive species.

• Impervious surface must drain into site

• 75% Native Plants

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Rewards Rebate Program:

Tree Canopy• Will eventually shade or cover

impervious surface-reduces heat pollution

• 10’-15’ away from permanent buildings

• Tree is on our published canopy trees list

• Planted between September 15 and April 30th

• Root flare is exposed• $200.00/tree

Rewards Rebate Program:

Permeable Pavers• Installed by a certified ICPI

contractor with an additional certification in PICP

• Replaces existing impervious surface

• A downspout filter must be used if the downspout is connecting into the pavement.

• If downspout is connected to the system add $4.00/sq ft for impervious surface that downspout is handling

• 1,200 or $4.00 a square foot IA treated.

• Whichever $ amount is • greater.

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Rewards Rebate Program:

Pavement Removal• $4 per square foot for

conversion to a conservation landscape

• $2 per square foot for conversion to turf.

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Rewards Rebate Program:

Green Roofs• $10/ SF

• Minimum 250 square feet

• Must be on an existing roof

Rewards Rebate Program:

Rain Barrels and Cisterns• $1.00 per gallon

• $250 maximum per property for rain barrels; $500 maximum for cisterns

• must capture 200 gallons min. for rain barrels, 250 gallons min. for cisterns

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Rewards Rebate Program:

Dry Wells• $1.00 per gallon

• $600 per property

• May be linear drywell OR conventional dry well

• DIY or contractor installed

Easy Application process….• Fill out on line application (15 minutes!!)

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• We will come out for a preliminary site inspection before you start work meet with you and your client

• Locate/verify possible project sites

• You will need to contact miss utility, any required perk test results and submit a plan for our review and approval to start

• You will need to be PICP certified through the ICPI if installing permeable Pavers

EASY APPLICATION PROCESS

• Contact us when you are finished for final inspection

• Submit copies of receipts and signed POA (property owner agreement)

• Rebate check in 4-6 weeks

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Check out our website for more info on designs

www.rainscapes.org

Water Quality Protection Charge (WQPC)Credit Program

Once you install a RainScapes project you are eligible to applyfor  WQPC credit toreduce this annualcharge (included with your property taxes)

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NGICP

LEED

SITES

CBLP CERTIFICATION

MONTGOMERY COLLEGE

www.rainscapes.org

rainscapes@montgomerycountymd.gov

Adam Ohl 

RainScapes Principal Administrative Aide

adam.ohl@montgomerycountymd.gov

240‐777‐7702

RAINSCAPES PROGRAM CONTACT INFO:

RainScapes Team

Carla Ellern ,RLA, ASLA, LEED AP BD+CRainScapes Plannercarla.ellern@montgomerycountymd.gov 240‐777‐7756

Donna Evans, LEED GARainScapes Plannerdonna.evans@montgomerycountymd.gov240‐777‐7798

Pamela RoweRainScapes Plannerpamela.rowe@montgomerycountymd.gov240‐777‐7714

Ann English, RLA, ASLA, LEED AP BD+CRainScapes Program Managerann.english@montgomerycountymd.gov 240‐777‐7759