Low Impact Development Training

Module 1: Background

1.1: Introduction

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Sponsors

District Department of Transportation

U.S. Department of Transportation Federal Highway Administration

The Low Impact Development Center, Inc.

University of the District of Columbia

Funding for this project was provided through a grant from the Federal Highway Administration, U.S. Department of Transportation

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Contributors

The Low Impact Development Center, Inc.

John Shorb Landscaping, Inc.Logo

Groundwork Anacostia River, D.C.

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Copyright

Unless otherwise noted, Low Impact Development Training, funded by DDOT & DDOE, is licensed under a Creative Commons Attribution-NonCommerical-ShareAlike 3.0 Unported License.

Content provided by cited entities remains the property of those entities and may not be used without their explicit permission.

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Overview

• Course overview• Introduction to Stormwater• Basic Math Skills• D.C. Stormwater Regulations

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Motivation for this course

• Bioretention use is becoming widespread in the District and surrounding areas

• Landscaping businesses are increasingly requested to conduct maintenance of these facilities

• Proper maintenance requires use of specialized techniques

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Purpose of this course

• To teach owners and managers of small landscaping businesses how to properly maintain bioretention cells

• To give owners and managers a solid background in local stormwater regulations and basic bioretention design

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Who we are

• Neil Weinstein is the Executive Director of The Low Impact Development Center

• Dennis Chestnut is the Executive Director of Groundwork Anacostia River, DC

• Rasma Plato is a Landscape Designer with John Shorb Landscaping

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Topics to be covered

• Mathematics for the landscape industry• District stormwater regulations• Bioretention design and construction• Bioretention maintenance evaluation• Identification and maintenance of common

bioretention landscaping plants• Identification and control of common invasive

plants• Bioretention maintenance procedures

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Course Overview

• 6 weeks• 12 modules, 3 hours each• 9 classroom modules• 3 field modules

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Week 1

• Module 1: Background– Intro to stormwater– Basic math skills– D.C. stormwater regulations

• Module 2: Bioretention System Design and Construction Part 1– Design elements– Basic construction techniques– Examples– Sources– Plants and plant selection– Drainage structures and erosion control

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Week 2

• Module 3: Bioretention Systems Design and Construction Part 2– Doing business in the District– Bioretention costs and bids– Construction

• Module 4: Bioretention Design Exercise

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Week 3

• Module 5.1: Safety and Equipment– Tools– OSHA requirements– District requirements

• Module 5.2: Bioretention Landscaping Plants– Plant identification– Plants commonly used in bioretention

• Module 6: In Field Construction Demonstration

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Week 4

• Module 7: Bioretention Maintenance Evaluation– Visual indicators– Corrective actions

• Module 8: Bioretention Maintenance Evaluation Field Visits

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Week 5

• Module 9: Maintenance Requirements– District maintenance requirements

• DDOT maintenance schedule

– Virginia maintenance requirements– Maryland maintenance requirements

• Module 10: Weeds and Invasives– Plant identification review– Common weeds and invasive species– Control practices

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Week 6

• Module 11: Maintenance Practices– Routine maintenance of bioretention– Maintenance of rain barrels and cisterns– Maintenance of small permeable paver

installations

• Module 12: Class Maintenance Demonstration

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Intro to Stormwater

• Hydrologic Cycle• How urbanization impacts the hydrologic

cycle• How stormwater can be treated to

minimize these impacts

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Expected Outcomes

• Be able to describe why stormwater runoff is a problem

• Be able to explain how low impact development reduces the damaging effects of stormwater

Hydrologic Cycle

Diagram Courtesy of the Wisconsin Geological and Natural History Survey 19

Graphic by Livingston & McCarron, 1992 (Adapted by the California Office of Environmental Health Hazard Assessment (OEHHA))

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“Typical” Urbanized Coastal Area

21Photo Courtesy of the Low Impact Development Center, Inc.

Effects of Urbanization

• Impervious surfaces produce higher runoff rates, volume and duration of large flows

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How Does the Volume and Rate of Runoff Effect the Environment?

• Changes in land use (e.g. impervious cover, removal of natural vegetation) alter natural water flow on and below the earth’s surface. • This causes:

– stream bank erosion

– flooding– reduced base

flow in streams– degradation of

stream and river habitat

23Photo Courtesy of the Low Impact Development Center, Inc.

How Does Runoff Water Quality Effect the Environment?

• Runoff picks up trash, debris and pollutants:– sediment– oil and grease– fertilizers– road salts– pesticides– herbicides– pet wastes– and heat

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Photo Courtesy of the Low Impact Development Center, Inc.

Runoff from Roads &Parking Lots

• Roads and parking lots] constitute as much as 70 percent of total impervious cover in ultra-urban landscapes, and as much as 80 percent of the directly connected impervious cover.

• Roads tend to capture and export more stormwater pollutants than other land covers in these highly impervious areas, especially in regions of the country having mostly small rainfall events.

National Research Council, Urban Stormwater Management in the United States, October 2008.

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Typical Pollutants

Examples of Stormwater Pollutants Typical of Roads

Pollutant Source Effects

Trash ------- Physical damage top aquatic animals and fish, release of poisonous substances

Sediment/solids Construction, unpaved areas Increased turbidity, increased transport of soil-bound pollutants, negative effects on aquatic organisms’ reproduction and function

Metals•Copper•Zinc•Lead•Arsenic

Vehicle brake pads•Vehicle tires, motor oil•Vehicle emissions and engines•Vehicle emissions, brake linings, automotive fluids

Toxic to aquatic organisms and can accumulate in sediments and fish tissue

Organics associated with petroleum (PAHs)

Vehicle emissions, automotive fluids, gas stations

Toxic to aquatic organisms

Nutrients Vehicle emissions, atmospheric deposition

Promotes eutrophication and depleted dissolved oxygen concentrations

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Runoff from Compacted Soils

• Most urban soils are severely compacted, which limits their ability to infiltrate rainfall

• These areas become effectively impervious

• Runoff from compacted, bare soils carries high sediment loads

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Stormwater’s Effect onRegional Water Quality

*Source: Chesapeake Bay Program

• Annual loadings to the Bay:– 40 million pounds of nitrogen (15% of total

loading).– 3 million pounds of phosphorus (16% of total)– 1 billion pounds of sediment (10% of total)

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Impacts to the Anacostia River

• Stormwater runoff is a principal cause of poor water quality in the Anacostia River

• DDOT is making a major effort to restore the Anacostia River and revitalize the waterfront

Conventional Stormwater Management

• Collect runoff in open culverts or storm sewer inlets

• Pipe runoff away as quickly as possible towards:– stormwater ponds– streams and rivers

• Creates health hazards and eyesores

30Photo Courtesy of the Low Impact Development Center, Inc.

What is Low Impact Development?

• LID is a stormwater management approach with basic principles modeled after nature.

• The primary goal of LID is to mimic a site’s pre-development hydrology by managing runoff close to its source through:– infiltration– filtration– storage– evaporation– detention

31Photo Courtesy of the Low Impact Development Center, Inc.

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Low Impact Development

• LID features reduce stormwater runoff quantity and improve runoff quality by removing pollutants, therefore improving the quality of receiving streams and rivers

Water quality monitoring station for bioretention facility WNY

Photo Courtesy of the Low Impact Development Center, Inc.

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Minimize Runoff

• Minimize Impervious Areas

• Green Roofs• Rainwater Harvesting

Photo Courtesy of the Low Impact Development Center, Inc.

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Promote Infiltration

• Disconnect Impervious Areas

• Infiltration-based BMPs– Bioretention– Permeable pavement– Infiltration trenches– Infiltration basins

Photo Courtesy of the Low Impact Development Center, Inc.

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Slow down excess runoff

• Disconnect impervious areas

• Vegetated conveyances

• Detention-based BMPs

Photo Courtesy of the Low Impact Development Center, Inc.

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Cool down excess runoff

• BMPs that detain or retain runoff underground– Bioretention– Permeable pavement– Infiltration trenches

Photo Courtesy of the Low Impact Development Center, Inc.

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Filter excess runoff

• Remove pollutants prior to discharge

Photo Courtesy of the Low Impact Development Center, Inc.

Chicago

Alley with impermeable pavement

“green alley” with permeable pavement

Photos Courtesy of Chicago DOT

LID ExamplesLID Examples

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Photos Courtesy of Seattle Public Utilities

LID ExamplesSeattle LID Examples

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Navy LID Examples

Washington Navy Yard B-166 Parking Lot

Bioretention Permeable Pavers

LID Examples

40Photos Courtesy of the Low Impact Development Center, Inc.

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What is Bioretention?

• Bioretention is the most commonly used LID BMP

• It is a landscape feature that is specially designed to capture, treat, and infiltrate stormwater runoff

• This course is focused on the design, construction, and maintenance of bioretention

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Typical Urban Bioretention

Photo Courtesy of Credit Valley Conservation (CVC)

Photo Courtesy of the Low Impact Development Center, Inc.

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Review

• Urbanization increases stormwater runoff volume and pollutant loads

• This causes harm to receiving waters• Low impact development techniques

reduce the impacts of urbanization by minimizing runoff, promoting infiltration, and removing pollutants

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Resources

• USEPA’s LID Page: http://water.epa.gov/polwaste/green/

• The LID Center: http://www.lowimpactdevelopment.org/publications.htm

• DDOE’s RiverSmart Homes Program: http://ddoe.dc.gov/riversmarthomes