LID BMPs

Presented by:

The Low Impact Development Center, Inc. A non-profit water resources and sustainable design organizationwww.lowimpactdevelopment.org

The Low Impact Development Center, Inc. has met the standards and requirements of the Registered Continuing Education Program. Credit earned on completion of this program will be reported to RCEP at RCEP.net. A certificate of completion will be issued to each participant. As such, it does not include content that may be deemed or construed to be an approval or endorsement by RCEP.

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© Low Impact Development Center, 2012

The purpose of this presentation is to describe the Best Management Practices (BMPs) commonly used in Low Impact Development.

At the end of this presentation, you will be able to:• Describe the most commonly used LID BMPs• Explain what design variations exist and how they

can be deployed.

Purpose and Learning Objectives

1. 2. 3.

Treatment Train: BMP Hierarchy

Source controls Conveyance controls End of pipe controls

LID is Part of the Watershed Toolbox!

Structural and Non-structural

Vegetation HardscapeProprietary

• Buffers• Amendments• Bioretention• Permeable pavements• Rainwater harvesting• Green roofs• Proprietary systems

Classification and Examples

Importance of Buffers

Reduce nutrients Reduce thermal impacts

Provide habitat Protect wetland hydrology

Bay guidance ~ 100 ft.,

MA and CT: sliding scale 50 to 200 ft.

Types/Definitions

• Reforestation: Replacement• Aforestation: Establishment• Riparian Buffers: Corridors for

filtering/uptake/thermal/disconnection

**Some States, such as Maryland, have strict forest conservation and stream buffer regulations that effect SWM and other construction

• Compost amendments and filter soxx

• Runoff, Nutrient, and Sediment Reduction Goals!

• Recycling• Aesthetics

Bioretention

Rain Garden

Bioretention in a Box

Bioswale

Bioretention Trench

Bioswales

Pollutant Removal MechanismsChemical • Electrostatic / ion exchange within

Humic / clays / silts• Biological phytoremediation• Bioremediation• Storing and cycling nutrients

Physical • Sedimentation• Filtration • Adsorption • Precipitation

Permeable Surfaces

H(x)

h(x)

x

z

x = L1

U(x)

Permeable Friction Course

x = L20

Drainage divide

h(L1)

h(L2)

h(0) = h0

High Return on Investment

• Permeable Block Pavers• Permeable Concrete• Asphalt Friction Course

(permeable not allowed)

Permeable Paver H and H Objectives

Full exfiltrationPartial exfiltration – an infiltration & detention facility

No exfiltration – detention only; Impermeable liner

Partial Base Exfiltration

Ready Mix Concrete Research & Education Foundation

Rainwater Harvesting

Rainwater Harvesting Systems: Components to Maintain

• Collection• First Flush/Treatment• Storage• Overflow• Pump & Pressure Tank• Conveyance/End Use

NRDC – Santa Monica, CA

Cisterns at NRDC Santa Monica Office

• Cisterns installed beneath planting beds.

• Collected rainwater is added to greywater collection system and used for toilet flushing and irrigation.

• Building uses duel-flush toilets, waterless urinals, and drought-tolerant plants.

• 60% reduction in potable water demand.

Construction Cost Elements Rainwater Harvesting

• Rain barrels cost $100-$300• Cisterns cost several hundred to several thousand

dollars Components include:

• Storage tank• Downspout flow diverter• Pre-tank filtration• Post-tank treatment (if needed)• Distribution system (e.g., spigot and hoses, plumbing)

• Costs can vary significantly depending upon storage size, tank material, and location (above or below ground)

Green Roofs

Green Roof Layers

Waterproofing membraneRoot barrier (if the waterproofing is not

certified as root resistant)Drainage layer

Separation layerGrowth media layer

Plants

Courtesy: Roofscapes

Green Roof Benefits:

Rainwater captureEnergy savings

Extended membrane life

Green Roof Construction Cost Elements

• Costs range from $15-$20/sf based on the inclusion of:

• Growing medium• Plants• Drainage layer• Insulation layer• Root barrier• Waterproof membrane• Leak detention layer (optional)

• Costs can increase because of equipment, material availability and scheduling

Slide courtesy of the Center for Neighborhood Technology

The temperature above Chicago’s City Hall green roof averages 10 -15°F lower than the black tar roof. Difference can be 50°F or greater during the summer. Energy savings of $3,600 per year.

Urban Heat Island

Source: Green Roofs for Healthy Citieswww.greenroofs.org

Ford Motor CompanyRouge River Manufacturing Complex – Dearborn, MI

Pilot Study: Modular Tray System System Characteristics:• Flexibility• Size of system• Placement configuration• Ease of installation• Coarse stone ballast• Retrofit designs• Use existing drains• Specialized outlet designs• Detention time and Flow rate• Minimize clogging

Coarse Stone Ballast(expanded shale)

Orifice Outlet Controls

Demonstration: Retrofit Hydraulic Structure Design

System Characteristics:• Ease of installation

o Retrofit designso Storage on roof surfaceo Use existing drains

• Outlet Design:o V-notch weir

• Control flow rates• Temporary storage

o Grated weir cover• Intercept debris• Minimize clogging• Reduce maintenance

Existing Roof Drain

V-Notch Weir PlatesGrated Weir Cover

Engine House #3: Design

Engine House 3

Connectivity Dashboard

Task Specific User Dashboards - Research

Proprietary DevicesReproduce or enhance LID functions

May require separate installation and maintenance contracts

Annapolis

• Replace non-functioning oil-water separator• Enhanced landscaping• Trap sediments• Stewardship

Alumni Hall

Solomons parking lot and RV park

Construction of infiltration trenches

Proposed Carderock Roadway Retrofit

Existing Inlet

Discussion

• Reduction of impervious areas• Ability to receive regulatory credit for retrofits• BMP standard and specifications compliance• Traffic control / installation enhancement

Ft. Bragg LID Retrofit

Ft. Bragg LID Retrofit

Source: Army: Public Works Technical Bulletin 200-1-62

Discussion

• Designs do not have to be complicated• Field adjustments• Materials availability

• Bioretention cell retrofits

• Bioretention strip in parking lot median

• Permeable paver cells• Street tree filters• Roof leader disconnect• Rain barrels

LID Features Constructed

Washington Navy Yard

Construction

• WNY special design requirements • National Priority List facility• HDPE liners• Perforated pipe under drains• Bioretention cells - overflow weirs• Native, drought and flood resistant plantings

Willard Park Bioretention

The Willard Park parking area was retrofitted during the storm sewer system rehab project using bioretention as the main storm water LID technique

Willard Park Bioretention Strip

Liner Installation

Willard Park Bioretention Strip

Under drain and soil installation

Willard Park Bioretention Strip

Willard Park Bioretention Cell Under Construction

Overflow Weir to Storm Sewer

Native Plantings

Mulch Layer

Bioretention Soil Mix

Geotextile

Gravel Layer

Perforated Underdrain

Impermeable Liner

Willard Park Bioretention Cell Completed

Rain Barrel

Museum Bioretention Cells

Disconnect Roof Leaders to Bioretention

Potential Green Roof

Building 166 Parking Lot Retrofit

B-166 Bioretention (Prior to Plantings)

Slide 70

B-166 Permeable Paver Installation

Gravel Chips

Unistone Pavers

Gravel Chips

Gravel Layer

Perforated Underdrain

Impermeable Liner

B-166 Parking Lot Completed

Curb Inlet Tree Box

Compost Hardscape Applications

Dry Dock Scuppers

Boat Wash: Metals

Navy San Diego

Mesa Lodge

BEQ Swale

BEQ Vegetated / Rock Filter

Mesa Lodge Perimeter Vegetation

Thank you for your time.

QUESTIONS?

Low Impact Development Center, Inc.www.lowimpactdevelopment.org

301.982.5559