Sustainable stormwater management is an approach which shifts the emphasis on stormwater management from the heavily engineered "collect and convey" approach to one which relies on natural solutions to storage and treatment. "Collect and convey" approaches involve construction of expensive pipes, inlets and outfalls to collect stormwater which enters highway right of way and convey it to the nearest appropriate surface water body. Along the way, the stormwater mixes with pollutants such as oil and collects eroded sediments and discharges them into water bodies, as well. This often leads to the need for expensive "end of pipe" treatment. Collectively, "collect and convey" and "end of pipe" treatment is not only costly for DOTs to construct in the first place, but an ever increasing burden to maintain. Plus, the ecological footprint of these engineered infrastructure solutions is much larger and disturbs the natural hydrologic cycle. This results in resistance from state and federal permitting agencies due to elimination or reduction of the permeability of soils, increased "flashy" runoff, and general water quality degradation. In turn, it can extend project delivery times, sometimes substantially.
Sustainable stormwater management mimics nature by integrating management of stormwater runoff into the surrounding terrain, using systems like landscaped medians, swales and interchange areas to store and treat runoff. Pollutants are removed naturally by vegetation and soil, and the stormwater can then replenish groundwater. Natural hydrological cycles and the replenishment of groundwater are not disturbed, and pollutant treatment is usually more effective. Construction and maintenance costs are comparable and often can be less, particularly when stormwater management solutions are found at the watershed instead of the project level.
On April 16, 2009, ContextSensitiveSolutions.org and the Federal Highway Administration hosted a Sustainable Stormwater Management Practices webinar.
Wendi Goldsmith, President of the Bioengineering Group, Inc., and Clark Wilson, Urban Designer at the EPA Office of Smart Growth, discussed the importance of sustainable stormwater management practices, along with innovative strategies for natural onsite stormwater storage and treatment. Sustainable stormwater management seeks to eliminate, where possible, the negative impacts of construction activities that disturb the natural hydrologic cycle resulting in elimination or reduction in the permeability of soils, increased "flashy" runoff and general water quality degradation.
Article / Paper / Report
How stewardship benefits Seattle's streets
If all future development of downtown Seattle assumed an ethic of stewardship toward the streetscape and pedestrian experience, the urban fabric of our city would be greatly enhanced. We would see a more vibrant downtown with inviting storefronts, reduced crime, and improved mobility for pedestrians, cyclists and transit riders.
This handbook is meant to help developers, builders, and project sponsors include post-construction stormwater controls in their projects, in order to meet local municipal requirements. The municipalities in Alameda County (CA) have to require post-construction stormwater controls, permanent features included in a project to reduce pollutants in stormwater and/or erosive flows during the life of the project. Although this handbook is written primarily for sponsors of private development projects, its technical guidance also applies to publicly-sponsored projects and may be useful for training municipal staff.
Stormwater management is shifting from systems that rapidly collect and discharge stormwater to nearby waterways towards more sustainable methods. These newer strategies aim to reduce contaminant load and the volume of runoff by incorporating stormwater treatment into the design of urban landscapes. The re-design of street tree rootzone environments is an option for incorporating stormwater treatment measures into streetscapes, where space is limited. This article details the performance of a pilot scale street tree bioretention system in reducing nitrogen loads in urban stormwater.
Removing pollutants from urban stormwater runoff is a key component of the Water Sensitive Urban Design (WSUD) philosophy. Treating urban runoff can add value to the urban landscape as well as protecting downstream receiving-waters, providing a source of water suitable for some reuse applications. Creative selection of the type, shape and location of stormwater treatment elements enables runoff from urban areas to be treated in the streetscape rather than using a more traditional “end of pipe” treatment approach. Small vegetated stormwater treatment elements such as raingardens and street trees can add interest to streetscapes, use a wide range of vegetation and provide attractive self irrigating landscape features. Stormwater treatment elements can be integrated with streetscape features such as traffic calming devices, parking bays and seating.
A webinar hosted by Clark Wilson of the U.S. EPA's Smart Growth and Green Building Division, and Ellen Greenberg, from the University of California-Davis, Green Streets: From Gray Funnels to Green Sponges is now available online via the link below.
This is a resource for designing environmentally sound streets that can help protect streams and wildlife habitat. The handbook describes basic stormwater management strategies and illustrates street designs with features such as street trees, landscaped swales and special paving materials that allow infiltration and limit runoff. The handbook also provides guidance on balancing the needs of protecting stream corridors and providing access across those streams.
A green street can be defined as a street designed to:
integrate a system of stormwater management within its right of way
reduce the amount of water that is piped directly to streams and rivers
be a visible component of a system of "green infrastructure" that is incorporated into the aesthetics of the community
make the best use of the street tree canopy for stormwater interception as well as temperature mitigation and air quality improvement
ensure the street has the least impact on its surroundings, particularly at locations where it crosses a stream or other sensitive area.
The design and construction of green streets is one component of a larger watershed approach to improving the region's water quality, and requires a more broad-based alliance for its planning, funding, maintenance and monitoring.
This publication provides a roadmap for incorporating "best management practices" (BMPs) into New York City's right-of-way infrastructure capital program. The guidelines are written for the Department of Design and Construction (DDC), but they are also intended for use by planners, designers, engineers, public officials, and anyone else involved in constructing, operating, or maintaining the right-of-way.
Through publishing this document, the City and the Design Trust for Public Space seek improved environmental, social, and economic outcomes for the City's infrastructure investments. Furthermore, the Guidelines consider improving natural-system and human health an essential part of an infrastructure capital project.
The High Performance Infrastructure Guidelines allow for a practical, incremental approach to implementing best management practices. The BMPs that are described in Part Three of the document are applicable to a wide range of maintenance and capital construction work, including minor structural roadbed work, street resurfacing projects, sewer or water main rehabilitation, sidewalk construction projects, and major right-of-way reconstruction or new construction.
-- New York City Department of Design + Construction; Design Trust for Public Space
Managing storm water with porous or dense-graded hot-mix asphalt (HMA) pavements is attracting attention because of the role it can play in sustainable site design and storm water management. This technology is of interest to public works officials, consultants, engineers, land developers, contractors, environmental engineers, and others with an interest in minimizing the impact of development on the environment.
The concept is fairly new in Minnesota, however this design has been used successfully since the 1970s in the United States and Europe. This pavement structure has been used in various climate conditions and can provide many benefits including: storm water runoff control, groundwater recharge, reduction of drainage structures needed to comply with storm water regulations, reduction of right-of-way for retention ponds, reduction of curb and gutter, and increased skid resistance and safety.
The most common locations for use include parking lots and low volume roads, and in high activity recreational areas like basketball and tennis courts or playground lots. This paper discusses the general design and application of storm water HMA pavements for successful use of the concept, and recent projects in Minnesota.
The purpose of the Pennsylvania Stormwater Best Management Practices (BMP) Manual is to provide guidance, options and tools that can be used to protect water quality, enhance water availability and reduce flooding potential through effective stormwater management. This manual presents design standards and planning concepts for use by local authorities, planners, land developers, engineers, contractors, and others involved with planning, designing, reviewing, approving, and constructing land development projects.
This manual describes a stormwater management approach to the land development process that strives to:
First, prevent or minimize stormwater problems through comprehensive planning and
development techniques, and
Second, to mitigate any remaining potential problems by employing structural and non-structural BMPs.
Manual users are strongly encouraged to follow the progression of prevention first and mitigation second. Throughout the chapters of this manual the concept of an integrated stormwater management program, based on a broad understanding of the natural land and water systems, is a key and recurring theme. Such a thorough understanding of the natural systems demands an integrated approach to stormwater management, so critical to “doing it better, doing it smarter.”
This manual provides guidance on managing all aspects of stormwater: rate, volume, quality, and groundwater recharge. Controlling the peak rate of flow during extreme rainfall events is important, but it is not sufficient to protect the quality and integrity of Pennsylvania streams. Reducing the overall volume of runoff during large and small rainfall events, improving water quality, and maintaining groundwater recharge for wells and stream flow are all vital elements of protecting and improving the quality of Pennsylvania’s streams and waterways.
-- Pennsylvania Department of Environmental Protection
Porous pavements are those made with built-in void spaces that let water and air pass through. They are the most radical, most rapidly developing, and most controversial way of restoring large parts of the urban environment. They have been called "the holy grail of environmental site design" and "potentially the most important development in urban watersheds since the invention of the automobile".
Recently, an eight-year-long research project concluded with the publication of this technology's first comprehensive overview (Ferguson, 2005). This paper describes the making of the book Porous Pavements, and the current types and extent of applications of porous concrete and other porous paving materials in North America.
The conclusion of this research is that regional ponds with horizontal wells can be used as a source of water for irrigation. This research is significant because the use of stormwater from regional ponds will reduce the amount of surface discharge pollutants from the ponds, and provide for an alternative water supply, that can be used for irrigation. Decreasing the quantity of water pollutants discharging into receiving waters will help meet total maximum daily load (TMDL) limits as well as lower the cost of maintenance of highway vegetation.
Roads and parking lots provide important opportunities for managing stormwater because they constitute as much as 70 percent of the total impervious cover in ultra-urban landscapes.
In 2007, the City/County Association of Governments of San Mateo County (C/CAG) enthusiastically supported the recommendation from its San Mateo Countywide Water Pollution Prevention Program Technical Advisory Committee to develop this Sustainable Green Streets and Parking Lots Design Guidebook.
The guidebook provides designers, builders, municipal staff, and other interested groups practical and state-of-the-art information on creating low-impact development roadways and parking lots within San Mateo County.
-- San Mateo Countywide Water Pollution Prevention Program
This manual provides instructions for the selection and implementation of construction site best management practices (BMPs). Caltrans requires contractors to identify and utilize these BMPs in the preparation of their Stormwater Pollution Prevention Plan and Water Pollution Control Program. Construction site BMPs are best conventional technology/best available technology-based BMPs that are consistent with the BMPs and control practices required under the Clean Water Act.
These Guidelines, geared specifically to developers and designers, will provide a vision for integrating green stormwater treatment into the site planning and building design of new development. Additional efficiencies in development will also be gained from pedestrian-friendly parking strategies. The parking and green design solutions range from shared district parking facilities to green roofs to containerized bioretention gardens. All are tailored for Emeryville's unique context: heavily urbanized sites, compacted or even contaminated soils, and a high water table. Because these Guidelines include a thorough numeric, hydraulic sizing methodology for various facility types, it will enable City staff, planners, designers, and developers to implement sustainable design on many scales throughout Emeryville. Implementation of the guidelines will allow Emeryville to be increasingly competitive in attracting research and knowledge-based businesses and develop additional housing opportunities for those interested in Emeryville's urban lifestyle.
Street trees in urban environments suffer from a severe limit of space available for plots. This combined with conventional drainage systems that take water away from the site lead to limitations on the health, growth and potential development of the trees. The impermeable environment exacerbates the already disturbed, deoxygenated and contaminated soil conditions by requiring surface compaction of these small spaces.
Trees in urban environments can also adversely affect adjacent infrastructure. As the tree grows, the roots seek out sources of water and grow along this path. These sources can be located under roads, inside pipes or adjacent to housing. These roots cause cracking of the road pavement, pipes and footings and can cause heaving of the footpath and gutter. This is a major concern to councils as the funds required to remove the roots and reinstate the damaged area are significant.
A field research project has commenced that will trial systems that harvest road runoff (for "irrigation" of street trees) and provide water quality and quantity benefits, reducing the impacts of stormwater on receiving environments. A controlled "irrigation" system will encourage the tree roots to grow towards the distribution source and away from the adjacent infrastructure. This will direct the roots to grow parallel to the roadways and houses, with the ultimate goal of keeping the roots within the strip of land between the roadway and the footpath.
This industry publication provides a number of web resources that include the latest news and articles on stormwater management, upcoming events and online discussions.
The Stormwater Manager's Resource Center is designed specifically for stormwater practitioners, local government officials and others that need technical assistance on stormwater management issues. Created and maintained by the Center for Watershed Protection, the SMRC has everything you need to know about stormwater in a single site.
The overall goal of this field study was to evaluate the potential effectiveness of vegetated highway embankments as a stormwater runoff best management practice (BMP) for retention of metals, polycyclic aromatic hydrocarbons (PAHs), and particulates. The study characterized roadway sediment particulate matter, annual pollutant mass loading, and long-term pollutant retention for three field sites in eastern Kansas.
The handbook describes the role of street trees in managing stormwater and includes detailed color drawings of the trees that best perform this function in the Portland metropolitan area. Street trees provide many benefits including calming traffic, improving air quality and conserving energy. Trees for green streets explains how to use street trees as a stormwater management tool.
Street trees perform a variety of functions that help reduce the amount and rate of stormwater runoff entering the piped stormwater system. Trees absorb water through their leaves, branches and roots. Trees planted in biofiltration swales slow down water flow even more by allowing water to infiltrate into the soil. While all street trees perform these functions, particular species may perform them better than others depending on characteristics such as:
persistent foliage
canopy spread
longevity
growth rate
drought tolerance
tolerance to saturated soils
resistance to urban pollutants (air and water)
tolerance to poor soils
root pattern
bark texture
foliage texture
branching structure
canopy density
Appropriate tree species are illustrated in the book, along with a description of major characteristics and advantages and disadvantages of each tree. The street tree guide focuses on the Portland, Ore. region, but tree suggestions apply to any West Coast temperate climate from Vancouver, B.C. to parts of Northern California.
This site contains technical and regulatory information about the National Pollution Discharge Elimination System (NPDES) stormwater program. It is organized according to the three types of regulated stormwater discharges – municipal separate storm sewer systems (MS4s), construction activities, and industrial activities. It also provides links to general stormwater topics and tools available.
Communities across the country are adopting smart growth strategies to reach environmental, community, and economic goals. The environmental goals include water benefits that accrue when development strategies use compact development forms, a mix of uses, better use of existing infrastructure, and preservation of critical environmental areas. While the water quality and stormwater benefits of smart growth are widely acknowledged, there has been little explicit regulatory recognition of these benefits to date.
Regulations under the National Pollutant Discharge Elimination System (NPDES) stormwater program offer a structure for considering the water quality benefits associated with smart growth techniques. Compliance with federal, state, and local stormwater programs revolves around the use of "Best Management Practices," or BMPs, to manage stormwater. Given the "built in" water benefits of smart growth at the site, neighborhood and watershed levels, smart growth techniques and policies are emerging as BMPs to manage stormwater runoff over the life of development and redevelopment projects.
The goal of this document is to help communities that have adopted smart growth policies and plans recognize the water benefits of those smart growth techniques and suggest ways to integrate those policies into stormwater planning and compliance. Taking credit for the work a community is already doing can be a low-cost and practical approach to meeting water quality goals and regulatory commitments. Examples of smart growth techniques and approaches covered in this publication include:
Regional planning
Infill development
Redevelopment policies
Special development districts (e.g., transit oriented development and brownfields redevelopment)
Tree and canopy programs
Parking policies to reduce the number of spaces needed or the footprint of the lot
"Fix It First" infrastructure policies
Smart growth street designs
Stormwater utilities
To request printed copies of this report, contact EPA's National Service Center for Environmental Publications at (800) 490-9198 or e-mail at nscep@bps-lmit.com and ask for publication number EPA 231-B-05-002.
