Stormwater management, green infrastructure and the challenges of redevelopment

Smart growth strategies are a key part of protecting water quality. Compact, mixed-use development means fewer paved and impervious surfaces, which helps reduce environmentally damaging stormwater runoff. Walkable neighborhoods with transportation choices mean fewer vehicle miles traveled, which helps reduce air pollution that falls into rivers as rain. And redeveloping greyfields or brownfields can significantly improve the environmental performance of a building site, while accommodating growth that might otherwise occur in greenfields.

Green infrastructure – including green roofs, rain gardens, tree plantings and permeable pavement – can go even further to protect water quality. Environmental advocates (including Smart Growth America) support rules that would require green infrastructure for new development projects as a way to protect waterways and water quality. But should redevelopment projects be subject to the same regulatory requirements for stormwater as greenfield development?

Because redevelopment already benefits water quality, and because it already faces greater regulatory and site-specific hurdles than greenfield development, many advocates argue no. Several groups, including Smart Growth America, have expressed concern that holding redevelopment projects to the same stormwater standards as greenfield development will raise the cost of these projects and discourage developers from reusing already-developed land. Water quality groups counter that evidence is lacking to support this fear, and that other regulatory factors are more significant in making development decisions.

A new report commissioned by Smart Growth America, in collaboration with American Rivers, the Center for Neighborhood Technology, River Network and the Natural Resources Defense Council examines what impact, if any, green infrastructure regulations would have on developers’ decisions about where and how to build. The report is particularly relevant in light of a forthcoming rule from the EPA that would strengthen the regulation of polluted stormwater from development projects.

The report looked at three communities that have among the strongest stormwater standards in the country: Philadelphia, PA; Montgomery County, MD; and Olympia, WA. Philadelphia and Montgomery County both require the use of green infrastructure. Overall, the report finds that redevelopment is compatible with the stormwater regulations in these communities, and that there appeared to be little, if any impact on where and what developers chose to build.

The report makes a clear case that opponents of the strong but flexible stormwater rules in each of these communities overstated the risks to the redevelopment market. The question of how strong a standard redevelopment can bear and how flexible the standard should be remains open, and we hope to explore those issues as the EPA’s rulemaking process goes forward. But the report does highlight some important caveats when it comes to helping redevelopment and water quality protection work hand in hand.

First of all, construction site conditions can make it difficult and costly to incorporate green infrastructure techniques in redevelopment projects. Site-related issues such as soil contamination and compaction, imperviousness, existing onsite infrastructure and limited land availability can all limit the range of treatment options and drive up engineering and construction costs. In order to allow redevelopment projects to go forward in the face of these hurdles, the communities investigated in the report employed various “off ramps” or compliance alternatives, including fee-in-lieu and offsite mitigation options, alternative treatment practices and reduced performance criteria. This flexibility is critical to the success of many projects.

Second of all, the communities examined in the report permit but do not require the use of some techniques – like green roofs and water capture systems – that are usually among the most expensive. If these techniques were required in circumstances where they were the only technically viable option for meeting a stormwater standard, the financial impact on redevelopment projects could be significant.

These challenges are unique to redevelopment projects, and all water quality advocates agree that greenfield development projects should be universally held to the strictest possible stormwater standards. As the report discusses, the site restrictions and variability that plague redevelopment are generally absent for greenfields and therefore the costs of stormwater management are significantly lower.

At the end of the day, a new rule from the EPA that establishes strong but realistic and flexible standards for redevelopment, combined with a very strict, “no net loss” approach for greenfields, will put communities across the country on the path toward achieving our clean water goals and spur the building of the vibrant, healthy communities where people want to live and work.

Click here to download the report: Managing Stormwater in Redevelopment and Greenfield Development Projects Using Green Infrastructure