The mission of the GHP Stormwater Management Group is to integrate public and private stakeholder interests in the restoration and sustainable usage of natural resources, centered on a “Watershed Based Approach.” Such an approach—as detailed below— will serve as a model for watershed-management in the Mid-Atlantic and, eventually, throughout the country.

The objectives of this group are to implement a collaborative, watershed based approach to stormwater management focused on results. Recognizing that highways coexist with other land uses and that cost effective approaches to stormwater management can yield watershed protection, even improvement if we integrate planning, maintain flexibility, and focus on results.

Moving Policy to Practice

A prototype for GHP transforming this objective into practice is the “From Main Streets to Green Streets!: "Collaboration for Prosperity and Sustainability" campaign with the town of Edmonston, Maryland’s Green Street the premier example. Utilizing ARRA funding the Town of Edmonston’s Decatur Street is a model for sustainable, green land use planning for low income communities in the Anacostia Watershed of the Chesapeake Bay.

The Green Street design for Decatur Street demonstrates a multi-benefit infrastructure approach which provides a Top to Bottom Plan (Tree Canopy to Water Quality). This comprehensive Plan includes replacing the native tree canopies, installing energy efficient lighting and using clean energy, integrating placement of stormwater management features with walkways and bikeways while adding traffic calming techniques. All these features are included while maintaining the existing two travel lanes and without taking property from residents. These green practices include rain gardens, permeable concrete and native trees which will treat rain where it falls and reduce the flow of stormwater pollution to the Anacostia. The new green infrastructure practices are sized to treat 90 percent of the annual total rainfall and provide improved air quality and other environmental benefits. The social, economic and environmental benefits also include:

Social

• Reduction in urban heat island effect

• Provides “green jobs’/”green business” opportunities

• Educational information provided through street kiosks

• Crime reduction

• Health benefits through walking, biking, running trails

Economic

• Energy cost reduction using wind powered LED lighting

• Water conservation

• Green Enterprise Business Opportunities

Environmental

• Carbon sequestration

• Improved water quality through 90% capture of stormwater

• Carbon footprint reduction

• Recycling and beneficial use.

    GREEN STREET DESIGN

More information on the Town of Edmonston, Maryland’s Green Street can be found at: http://edmonstonmd.gov/GoingGreen.html

Another way GHP has been helping to translate policy into practice is through continuing education. GHP through the GHP Training and Development Center in partnership with the American Society for Civil Engineers developed the Green Highways and Green Streets for 21st Century Infrastructure: Strategies, Technologies, and Funding webinar training for planners and engineers involved in infrastructure planning at the federal, state, municipal and local levels. This training was first offered in October 2009 and provided an introduction to the GHP Green Infrastructure/Watershed Approach design concepts and applications. The content also shows how engineers are actively using this program to help communities meet their 21st century infrastructure, jobs, and community development needs, while providing for improved stormwater management and environmental protection. The first webinar had participation from 64 sites representing federal, state and local governments, educational institutions, and private consulting firms.

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WATERSHEDS 101

Watersheds are areas of land that drain water, sediment and dissolved materials to a common receiving body or outlet, and they are critical to environmental, financial, and social health. Regardless of a watershed's size (they can range from a few acres to thousands of square miles), each plays an essential eco-system role. They support innumerable interrelated ecological processes and even a slight change to just a single factor (be it climate, geology, hydrology, soil, or vegetation) could result in profound impact. Therefore, the concept of watershed management is vital to the Green Highways Partnership.

The Environmental Protection Agency has outlined four core principles of watershed management http://www.epa.gov/watertrain/watershedmgt/principlea.html

Watersheds are dynamic ecosystems; in other words, natural change is inevitable and necessary. Natural change comes in the form of floods, fire, drought, glacial movement, and tectonic shifts, among other agents. On the other hand, human-made change can yield different (often negative) results. Watershed management focuses heavily on measures to avoid, minimize or otherwise remediate human-made changes. According to the Center for Watershed Protection, there are eight tools to protect or restore aquatic resources in an urbanized or developing watershed:

Tool 1. Land Use Planning

Tool 2. Land Conservation

Tool 3. Aquatic Buffers

Tool 4. Better Site Design

Tool 5. Erosion and Sediment Control

Tool 6. Stormwater Best Management Practices

Tool 7. Non-Stormwater Discharges

Tool 8. Watershed Stewardship Programs

Watershed management entails utilizing different aspects of each tool to yield the most powerful strategy possible. Effective management provides local communities with a realistic approach for maintaining a quality environment for future generations.

The EPA's online Watershed Academy Web is the premier resource for detailed watershed management information. Each training module provides expert insight into all aspects of the watershed management field. Click here to explore the site.

Watershed Management Links:

• EPA Priority Watersheds Tool - See a map of priority watersheds based on watershed resources and stressors

• EPA Region 3 Water - Information regarding watersheds management within the Mid-Atlantic states

• Nonpoint Source Pollution - Learn about nonpoint source pollution managment programs in the Mid-Atlantic region

• Targeted Watershed Grants - How to get money from the EPA to implement your own watershed management projects

• FHWA Exemplary Ecosystem Initiatives - FHWA recognized projects for excellence in addressing the needs of the ecosystem

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WHY TRANSPORTATION & WHY WATERSHEDS?

Transportation planning is undergoing significant changes due in part to a growing awareness in the scientific and government communities of the need for more integrated ecosystem approaches and transportation regulation that requires more ecologically sensitive transportation planning and design. (venner, september 2005)

Applying stormwater management techniques to address water quality and water quantity concerns is now common practice in highway projects. Best management practices (BMP) are typically designed to meet regulatory requirements, and are focused on treating and manag¬ing runoff within the rights-of-way (row) of highways. Whereas, the GHP approach focuses on activities beyond the right-of-way and within the watershed for better-than-before results.

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WATERSHED APPROACH

The Green Highways Watershed Approach to stormwater management, recognizes that highways coexist with other land uses within watersheds, and a collaborative approach provides an opportunity for highway agencies to plan and deliver the most cost-effective protection, even improvement, to watersheds. To aid in watershed recovery, address watershed impairments, and to be prepared to address future potential water quality standard requirements, designers must begin thinking outside of the right-of-way.

The following principals outline the framework for the GHP Watershed Approach.

PRINCIPLES: 

The Maryland State Highway Administration (MDSHA) has made tremendous progress in developing watershed-based stormwater management strategies.  The late Raja Veeramachaneni, in his career with MDSHA, became a pioneer in this area; he pointed out that conventional approaches to stormwater management are focused on point discharges and designed only to meet regulatory requirements.  However, these practices don’t necessarily address watershed needs.  To aid in watershed recovery, address watershed impairments, and still fulfill Total Maximum Daily Load (TMDL) requirements, designers must begin thinking outside of the right-of-way.  Utilizing this approach, the Team plans to implement pilot projects in the Mid-Atlantic that will improve watershed health and serve as examples for the country.  As you can see from the chart below, the potential benefits are enormous.

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GHP STORMWATER TECHNOLOGIES

Innovative BMP’s for Stormwater Management
When stormwater is not properly managed, negative impacts to local ecosystems and communities can take the form of flooding and/or toxin leaching. 

GHP has been working to compile an innovative stormwater “Best Management Practices” system.  In order to surpass the current standard, researchers have had to think outside the box--while maintaining a focus on feasibility.  So far the results have been very promising.

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LOW IMPACT DEVELOPMENT
Low Impact Development (LID) is an innovative stormwater management approach with a basic principle that is modeled after nature:

LID's goal is to mimic a site's predevelopment hydrology by using design techniques that infiltrate, filter, store, evaporate, and detain runoff close to its source. Techniques are based on the premise that stormwater management should not be seen as stormwater disposal. Instead of conveying and managing / treating stormwater in large, costly end-of-pipe facilities located at the bottom of drainage areas, LID addresses stormwater through small, cost-effective landscape features located at the lot level. These landscape features, known as Integrated Management Practices (IMPs), are the building blocks of LID. Almost all components of the urban environment have the potential to serve as an IMP. This includes not only open space, but also rooftops, streetscapes, parking lots, sidewalks, and medians. LID is a versatile approach that can be applied equally well to new development, urban retrofits, and redevelopment / revitalization projects.

Figure 1

The Low Impact Development Center has been a valuable partner in the compiling and dissemination of LID technology and practice.

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BIORETENTION
Bioretention is a best management practice (BMP) developed in the early 1990's by the Prince George's County, MD, Department of Environmental Resources (PGDER). Bioretention utilizes soils and both woody and herbaceous plants to remove pollutants from storm water runoff. As shown in Figure 1, runoff is conveyed as sheet flow to the treatment area, which consists of a grass buffer strip, sand bed, ponding area, organic layer or mulch layer, planting soil, and plants. Runoff passes first over or through a sand bed, which slows the runoff's velocity, distributes it evenly along the length of the ponding area, which consists of a surface organic layer and/or ground cover and the underlying planting soil. The ponding area is graded, its center depressed. Water is ponded to a depth of 15 centimeters (6 inches) and gradually infiltrates the bioretention area or is evapotranspired.

The bioretention area is graded to divert excess runoff away from itself. Stored water in the bioretention area planting soil exfiltrates over a period of days into the underlying soils.

This text was obtained from the US EPA.  For more information on bioretention see, http://www.epa.gov/owm/mtb/biortn.pdf

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STORMWATER WETLANDS
Stormwater wetlands (a.k.a. constructed wetlands) are structural practices similar to wet ponds that incorporate wetland plants in a shallow pool. As stormwater runoff flows through the wetland, pollutant removal is achieved by settling and biological uptake within the practice. Wetlands are among the most effective stormwater practices in terms of pollutant removal, and also offer aesthetic value. While natural wetlands can sometimes be used to treat stormwater runoff that has been properly pretreated, stormwater wetlands are fundamentally different from natural wetland systems. Stormwater wetlands are designed specifically for the purpose of treating stormwater runoff, and typically have less biodiversity than natural wetlands both in terms of plant and animal life. There are several design variations of the stormwater wetland, each design differing in the relative amounts of shallow and deep water, and dry storage above the wetland.

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WETLAND RESTORATION
Restoration practitioners typically implement only the actions necessary to re-establish natural wetland processes on a site. The first method to consider for renewing functions is to remove the factors causing wetland degradation or loss and let nature do the work of restoration.

This method is often called the passive approach. For example, if wetland vegetation and water quality are degraded primarily as a result of cattle grazing, then removing the cows may be the only activity needed to restore the wetland system. Passive methods allow natural regeneration of wetland plant communities, natural re-colonization by animals, and re-establishment of wetland hydrology and soils. Passive approaches are most appropriate when the degraded site still retains basic wetland characteristics and the source of the degradation is an action that can be stopped. The success of passive methods usually depends on an accessible source of water, the close proximity of wetland plants and animals, and a mechanism for bringing species to the restoration site. The benefits of passive methods include low cost and a high degree of certainty that the resulting wetland will be compatible with the surrounding landscape.

For many sites, passive methods are not enough to restore the natural system and an active approach is necessary. Active approaches involve physical intervention in which humans directly control site processes to restore, create, or enhance wetland systems. The active approach is most appropriate when a wetland is severely degraded or when goals cannot be achieved in any other way, as is the case with wetland creation and most enhancements. Active methods include re-contouring a site to the desired topography, changing the water flow with water control structures (i.e., weirs or culverts), intensive planting and seeding, intensive non-native species control, and bringing soils to the site to provide the proper substrate for native species. The design, engineering, construction, and costs for such work can be significant.

RIPARIAN FOREST BUFFERS
Riparian forest buffers are areas of forested land adjacent to streams, rivers, marshes or shoreline that form the transition between land and water environments. Although riparian areas comprise only about 5 to 10 percent of the land in the watershed, they play an important role in maintaining the health of watersheds.

Forests are the most effective type of riparian buffer available. Riparian forest buffers improve water quality while providing habitat for wildlife and fish.

Riparian buffers are key to controlling non-point source pollution. They also:

The type, size and effectiveness of riparian buffers vary based on the location, environmental management needs and landowner needs. The width of each zone is determined by specific site conditions and landowner objectives.

This text was obtained from the Chesapeake Bay Foundation.  For more information on forest buffers, see http://www.chesapeakebay.net/forestbuff.htm.

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STREAM RESTORATION
Restoration, as defined in this document, includes a broad range of actions and measures designed to enable stream corridors to recover dynamic equilibrium and function at a self sustaining level. The first and most critical step in implementing restoration is to, where possible, halt disturbance activities causing degradation or preventing recovery of the ecosystem. Restoration actions may range from passive approaches that involve removal or attenuation of chronic disturbance activities to active restoration that involves intervention and installation of measures to repair damages to the structure of stream corridors. Restoration practitioners involved with stream corridors take one of three basic approaches to restoration

NOTE: Nonintervention and undisturbed recovery: where the stream corridor is recovering rapidly, and active restoration is unnecessary and even detrimental.

Partial intervention for assisted recovery: where a stream corridor is attempting to recover, but is doing so slowly or uncertainly. In such a case, action may facilitate natural processes already occurring.

Substantial intervention for managed recovery: where recovery of desired functions is beyond the repair capacity of the ecosystem and active restoration measures are needed.

This text was obtained from the Federal Interagency Stream Corridor Restoration Working Group.  For more information on stream restoration, see: http://www.nrcs.usda.gov/technical/stream_restoration/newgra.html.

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POROUS PAVEMENTS
Porous pavement is a permeable pavement surface with an underlying stone reservoir that temporarily stores surface runoff before infiltrating into the subsoil. This porous surface replaces traditional pavement, allowing parking lot runoff to infiltrate directly into the soil and receive water quality treatment. There are several pavement options, including porous asphalt, pervious concrete, and grass pavers. Porous asphalt and pervious concrete appear the same as traditional pavement from the surface, but are manufactured without "fine" materials, and incorporate void spaces to allow infiltration. Grass pavers are concrete interlocking blocks or synthetic fibrous grid systems with open areas designed to allow grass to grow within the void areas. Other alternative paving surfaces can help reduce the runoff from paved areas but do not incorporate the stone trench for temporary storage below the pavement.
 

ENVIRONMENTALLY FRIENDLY CONCRETE
There are many problems associated with traditional concrete.  Concrete production requires a vast amount of resources and emits tremendous amounts of waste.  Moreover, highways constructed from traditional concrete leach toxins into the surrounding ecosystems.
 
But Green Highways technologies have the potential to solve these challenges.  The incorporation of recycled industrial byproducts can significantly reduce concrete production waste and resources.  For example, Coal Combustion Products are generated when coal is burned in powerplants.  Utilizing CCP’s such as fly ash, bottom ash, boiler slag, and flue gas desulfurization gypsum can save virgin resources, reduce energy consumption and greenhouse gas emissions, and reduce the need for landfill space and new landfills.  Similarly, slag cement is a byproduct of iron manufacturing.  Slag cement has many of the same benefits as do CCP’s and it helps make concrete better and more consistent.
  
How does a green highway eliminate toxic leaching?  The answer is in porous concrete pavement technology.  This technology utilizes a permeable pavement surface with an underlying stone reservoir that temporarily stores surface runoff before infiltrating into the subsoil. Runoff infiltrates directly into the soil and receives water quality treatment. Since the reservoir area underneath porous pavement stores and infiltrates surface runoff, using porous concrete pavement will significantly reduce the amount of land needed for traditional stormwater management measures. Porous pavement increases groundwater recharge, reduces pollutants in stormwater runoff, and helps alleviate flooding and contamination to streams.

The current standards for concrete production are not sustainable. Consider this: every year, the international concrete industry utilizes 1.6 billion tons of cement, 10 billion tons of rock and sand, and 1 billion tons of water. Each ton of cement requires 1.5 tons of limestone and extensive amount of fossil fuel and electrical energy. The production of each ton of cement is accompanied with one ton of carbon dioxide emissions--one of the greenhouse gases primarily responsible for global warming. Overall the contribution of the cement industry to the world’s total carbon dioxide emissions is about seven percent. Hope comes in the form of Environmentally Friendly Concrete, or EFC. EFC fosters sustainability by:

This information comes directly from Dr. Mohammad S. Khan's insightful presentation, Environment-Friendly Concrete (EFC) for Green Highways.  Dr. Khan, Senior Vice President of Professional Service Industries, Inc., delivered this at the GHP Forum.

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SOIL AMENDMENTS
By restoring or improving the physical and therefore hydrological characteristics of a soil, that soil can then best be utilized for stormwater management purposes.  Compared to compacted, unamended soils, amended soils provide greater infiltration and subsurface storage and thereby help to reduce a site's overall runoff volume, helping to maintain the predevelopment peak discharge rate and timing.  The volume of runoff that needs to be controlled in order to replicate natural watershed conditions changes with each site based on the development's impact on the site's curve number (CN), a measure of infiltration based upon soil type and land-use.

Soil amendments also address water quality by increasing the spacing between soil particles so that the soil can absorb and hold more moisture.  This in turn reduces runoff and the damaging effects of excessive runoff on local streams. The amendment of soils changes various other physical, chemical and biological characteristics so that the soils become more effective in maintaining water quality.

This text was obtained from the Low Impact Development Center.  For more information on soil amendments, see:

http://www.lidstormwater.net/soilamend/soilamend_benefits.htm

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STORMWATER RESEARCH
The field of watershed-driven stormwater management is constantly evolving. 
The Green Highways Partnership Stormwater Group has identified a number of crucial research opportunities surrounding highway stormwater management practices. The targeted research areas encompass BMP maintenance, modeling, and effectiveness, pollutant trading, and information sharing.  Listed below are research opportunities currently  being addressed by Partnership experts, include:

GREEN HIGHWAYS PARTNERSHIP BMP ASSESSMENT

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