Design Principles

for Stormwater Management on Compacted,

Contaminated Soils in Dense Urban Areas

EPA’s Brownfields Program is designed to empower states, communities, and other stakeholders in economic 

redevelopment to work together in a timely manner to prevent, assess, safely clean up, and sustainably reuse brownfields. 

A brownfield is a property, the expansion, redevelopment, or reuse of which may be complicated by the presence or 

potential presence of a hazardous substance, pollutant, or contaminant. EPA’s Brownfields Program provides fi nancial and 

technical assistance for brownfield revitalization, including grants for environmental assessment, cleanup, and job training. 

What is Green Infrastructure? 

Most development and redevelopment practices 

cover large areas of the ground with impervious 

surfaces such as roads, driveways, sidewalks, and 

new buildings themselves, which then prevent 

rainwater from soaking into the ground. These 

hard surfaces increase the speed and amount of 

stormwater that runs into nearby waterways, 

carrying pollutants and sediment each time it rains. 

Green infrastructure seeks to reduce or divert 

stormwater from the sewer system and direct 

it to areas where it can be infiltrated, reused or 

evapotranspirated. Soil and vegetation are used 

instead of, or in conjunction with, traditional 

drains, gutters, pipes and centralized treatment 

areas. In many new and redevelopment projects, 

green infrastructure is implemented to manage and 

mitigate the polluted runoff created by precipitation 

that falls on rooftops, streets, sidewalks, parking 

lots and other impervious surfaces. 

How can Green Infrastructure be Applied to 

Brownfi eld Sites? 

Preparing brownfields for redevelopment often 

requires capping of contaminated soils, creating 

even larger impervious surfaces. The challenge 

for managing stormwater on brownfi eld sites 

is allowing this capping while mitigating the 

impervious surface conditions that can negatively 

impact local waterways. 

Unlike many conventional developments, 

impervious footprints on brownfi elds cannot 

always be minimized through site designs that 

incorporate more porous surfaces to allow for 

infiltration. Direct infiltration on a brownfield 

site may introduce additional pollutant loads to 

groundwater and nearby surface waters. However, 

green infrastructure practices exist that can retain, 

treat and then release stormwater without it ever 

coming in contact with contaminated soils. 

A bioswale in Wilmington, 

Delaware, designed to absorb 

and retain stormwater runoff. 
The University of Michigan’s 

School of Natural Resources 

and Environment developed 

design guidelines that use 

low impact development 

techniques on contaminated 

sites. Using a former industrial 

site in Flint, Michigan, called 

Chevy in the Hole, graduate 

students considered and refined 

methods to prevent residual 

contamination from moving 

with stormwater. 

Design Considerations 

A key component of using 

green infrastructure for brownfield sites is treatment and storage of stormwater, rather than complete 

infiltration. Most brownfields that have residual contamination need caps, so vegetated areas need to 

be located above caps and fitted with underdrain systems to remove overfl ow stormwater. 

Development and redevelopment projects should start with keeping existing trees onsite, minimizing 

compaction of earth that inhibits water infiltration, and planting trees and other vegetation in 

areas where none exists. Retaining existing tree cover and vegetated areas helps infi ltrate and 

evapotranspirate stormwater runoff while intercepting large amounts of rainfall that would otherwise 

enter waterways as runoff. 

Buildings and other impervious surfaces can be strategically located to act as caps over areas with 

known contamination. Areas with fill caps can include soils and vegetation above the cap in the 

form of swales or rain gardens. If fitted with an under-drain system to release treated stormwater off 

site, these planted areas can safely allow filtration and evapotranspiration of stormwater. Additional 

features like impermeable liners or gravel filter blankets can be coupled with modified low impact 

development (LID) practices that safely filter stormwater without exposing the water to contaminated 

soils. 

Green roofs are an ideal way to reduce the runoff from building roofs by encouraging 

evapotranspiration of rainwater. Another option for brownfield sites is the capture and reuse of 

stormwater for non-potable uses; this can include runoff storage in rain barrels for irrigation of green 

roofs or landscaped areas, or in cisterns that store rainwater for toilet flushing and other uses. 

Site location within the watershed is very important. In particular, projects in groundwater recharge 

areas should avoid low impact development practices 

that promote infiltration, and use techniques that directly 

discharge treated stormwater instead. Furthermore, new 

and redeveloped sites near brownfields should use green 

infrastructure practices to prevent additional runoff from 

flowing onto potentially contaminated areas. 

Overall, when developing a stormwater management plan 

on a brownfield, surrounding sites must be considered. 

(Source: Flint Futures: Alternative Futures for Brownfield 

Redevelopment in Flint, Michigan.) The Matthew Henson Conservation Center 

in Washington, DC, utilizes a green roof. 

Blue arrows represent flows 

of surface and groundwater 

onto brownfi eld site 
General Principles for Using Green Infrastructure on Brownfi eld Sites 

Guideline #1: Differentiate between groups of contaminants as a way to better minimize risks. 

Guideline #2: Keep non-contaminated stormwater separate from contaminated soils and water to 

prevent leaching and spreading of contaminants. 

Guideline #3: Prevent soil erosion using vegetation, such as existing trees, and structural practices like 

swales or sediment basins. 

Guideline #4: Include measures that minimize runoff on all new development within and adjacent to a 

brownfield. These measures include green roofs, green walls, large trees, and rainwater cisterns. 

Definitions 

Bioswales are open channels with a dense cover of vegetation where runoff is directed or retained to 

evapotranspirate and fi lter. 

Evapotranspiration is the return of water to the atmosphere either through evaporation or by plants. 

Green Infrastructure and Low Impact Development (LID) both refer to systems and practices that use 

or mimic natural processes to infiltrate, evapotranspirate or reuse stormwater or runoff on the site where 

it is generated. 

Green roofs can be used to effectively reduce or eliminate runoff from small and medium sized storms. 

A soil mixture is placed over a waterproof membrane and drainage system and then planted with 

water absorbent and drought tolerant plants. Most systems also have root barriers. These roofs soak up 

stormwater and release it back into the atmosphere through evaporation and plant respiration, while 

draining excess runoff. 

Rain gardens serve the same purpose as stormwater planters and are appropriate where there is more 

area to plant vegetation. Sizing is dependent on the area of impervious surfaces draining to the rain 

garden, but they can be designed to only treat a portion of the runoff so they can be placed in most 

situations. 

Stormwater harvest and reuse. 

Rainwater harvested in cisterns, 

rain barrels, or other devices may 

be used to reduce potable water 

used for landscape irrigation, 

fire suppression, toilet and urinal 

flushing, and custodial uses. 

Storage and reuse techniques 

range from small-scale systems 

(e.g., rain barrels) to underground 

cisterns that may hold large 

volumes of water. 

Stormwater planters. 

Downspouts can be directed 

into stormwater planters. These 

planters are used to temporarily 

detain, filter and evapotranspirate 

stormwater using plant uptake. 
Additional Resources 

The Emeryville, California Stormwater Guidelines for Green, Dense Redevelopment provides guidance on 

using vegetative stormwater treatment measures for this dense, brownfield-laden city: 

www.ci.emeryville.ca.us/planning/stormwater.html. 

EPA’s Green Infrastructure Web site (www.epa.gov/npdes/greeninfrastructure) provides definitions, case studies 

and performance data for various practices that might be applicable to brownfi eld sites. 

The Low Impact Development Center is dedicated to research, development, and training for water resource and 

natural resource protection issues. The Center focuses specifically on furthering the advancement of Low Impact 

Development technology: www.lowimpactdevelopment.org. 

Green Roofs for Healthy Cities collects and publishes technical information on green roof products and services: 

www.greenroofs.org. 

The Center for Watershed Protection’s Better Site Design Tools provide links to various better site design 

resources and publications: www.cwp.org/PublicationStore/bsd.htm. 

American Rivers’ Catching the Rain: A Great Lakes Resource Guide for Natural Stormwater Management 

describes a variety of low impact development strategies that can be implemented in a wide range of built 

environments. Available at: www.americanrivers.org/site/DocServer/CatchingTheRain.pdf?docID=163

NRDC’s Rooftops to Rivers: Green Strategies for Controlling Stormwater and Combined Sewer Overflows is 

a policy guide for decision makers looking to implement green strategies in their own area, including nine case 

studies of cities that have successfully used green techniques to create a healthier urban environment. 

Available at: www.nrdc.org/water/pollution/rooftops/contents.asp

Portland’s (Oregon) Trees for Green Streets: An Illustrated Guide is a guidebook that helps communities select 

street trees that reduce stormwater runoff from streets and improve water quality. 

Available at: www.metro-region.org/article.cfm?articleID=263

Seattle’s pilot Street Edge Alternatives Project (SEA Streets) is designed to provide drainage that more closely 

mimics the natural landscape prior to development than traditional piped systems. Good information can be found 

at: www.seattle.gov/util/About_SPU/Drainage_&_Sewer_System/Natural_Drainage_Systems/Street_Edge_

Alternatives/index.asp

EPA’s Protecting Water Resources with Higher-Density Development report helps communities better 

understand the impacts of higher and lower density development on water resources. The findings indicate that 

low-density development may not always be the preferred strategy for protecting water resources. 

Available at: www.epa.gov/dced/water_density.htm.

Portland Metro’s (Oregon) Green Streets: Innovative Solutions for Stormwater and Stream Crossings is a 

handbook that describes stormwater management strategies and includes detailed illustrations of “green” street 

designs that allow infiltration and limit stormwater runoff. 

Available at www.metro-region.org/article.cfm?articleID=262

EPA’s Protecting Water Resources with Smart Growth is a report intended for audiences already familiar with 

smart growth concepts who seek specific ideas on how techniques for smarter growth can be used to protect water 

resources. The report describes 75 policies that communities can use to grow in the way that they want while 

protecting their water quality. Available at: www.epa.gov/dced/water_resource.htm

EPA’s Using Smart Growth Techniques as Stormwater Best Management Practices reviews nine common smart 

growth techniques and examines how they can be used to prevent or manage stormwater runoff. Available at: 

www.epa.gov/dced/stormwater.htm

EPA’s Brownfi elds Program Website (www.epa.gov/brownfields) provides information on and resources for 

assessing, cleaning up and redeveloping brownfields, including grant funding opportunities.

Design Principles for Stormwater Solid Waste EPA-560-F-07-231 

Management on Compacted, and Emergency April 2008 

Contaminated Soils in Dense Urban Areas Response (5105T) www.epa.gov/brownfields