Despite marked progress toward cleaner water over the 40-year history of the Clean Water Act, there is widespread agreement that much work is left to be done. One major gap in the protections under the landmark law is its inability to effectively reduce polluted stormwater runoff from developed and developing areas. This growing source of pollution from urbanized areas and the resulting growth in impervious surfaces continues to plague our rivers and streams across the country. The US Geological Survey’s Effects of Urbanization on Stream Ecosystems detailed the impacts that our waterways begin to suffer even at the earliest stages of urban development. This is problematic given that the creation of impervious surfaces continues to outpace population growth in most areas of the country. Meanwhile, existing federal stormwater regulations are largely ineffective at protecting water quality and have failed to keep up with advances in science, technology, and practice that have moved away from quickly conveying water offsite and toward retaining and reusing water where it falls.
Fortunately, EPA’s upcoming post-construction stormwater rule proposal offers a critical opportunity to update the municipal stormwater program by incorporating advances in innovation and technology while at the same time more equitably targeting sources of stormwater pollution. American Rivers believes that modernizing the municipal stormwater program to include objective, performance-based retention standards; expanding permit boundaries to target currently unregulated pollution sources; and requiring planned, incremental retrofits of existing impervious areas will cost-effectively improve clean water and help create healthy, vibrant communities.
Since EPA developed its original stormwater regulations, the science and practice of controlling stormwater runoff has evolved, often through advances at the local level. The 2009 National Research Council report found that the municipal stormwater permit program relies too heavily on vague and subjective permits and on management approaches that focus on rate rather than volume, leading to practices, like detention ponds that do little to improve water quality and can exacerbate stream impacts like erosion and sedimentation. Around the country, scientists, engineers, and practitioners have advanced our understanding of workable solutions by focusing on how to use green infrastructure to protect, restore, and replicate natural function in our developed and developing areas. Conferences and workshops on green infrastructure topics are increasingly in demand and rising in visibility, as demonstrated by last fall’s White House conference on green infrastructure. Today, a growing number of practitioners design and build an array of projects that demonstrate the geographic adaptability of green infrastructure and support a growing industry of vendors and businesses that are well represented at conferences like StormCon.
As we describe in our report A Guidebook to Permitting Green Infrastructure, select states and cities are integrating these advances into their stormwater permits and policies and using volume-based standards and green infrastructure to control stormwater. For example, in renewing the city of Boise, Idaho’s permit, EPA Region 10 incorporated a retention standard that effectively requires onsite management of the local 95th percentile storm. This follows a model set forward by EPA’s guidance for implementing stormwater provisions that apply to federal development projects after 2009. The permit for Ventura County, CA, adopts a different approach, limiting the effective impervious area created by development projects to a maximum of 3% of the site area. In these and other states and communities, retention standards that were once thought to be technically or economically impossible have proven to be feasible and achievable.
As more communities across the country move toward objective, performance-based approaches, it’s high time to establish an enforceable standard for our municipal stormwater programs nationwide. Creating a national federal minimum standard for development and redevelopment would provide much-needed objectivity to the stormwater program and for state permit writers and would drive the use of green infrastructure without prescribing specific practices. While flexibility may be needed in some urban redevelopment situations to account for site limitations, thus far redevelopment has not suffered in places with protective stormwater requirements. Any national standard must make clear that it will not undermine any strong local standards already in place, but rather provide accountability where none currently exists.
Arguably, one of the most significant limitations to EPA’s current stormwater regulations is the narrow universe of sources to which they apply. Currently, only 2% of the nation’s land area falls within the boundaries of regulated municipal separate storm sewer systems (MS4s). Even though this represents some of the most populous and developed areas of the country, most areas of recent suburban and exurban growth over the past 10 years fall outside the scope of state and federal stormwater programs. As a result, many municipalities bear the cost of addressing water-quality problems caused by stormwater from uncontrolled upstream areas outside the narrowly defined MS4 boundaries. Additionally, many commercial sites with large impervious surfaces, like malls and warehouses, are not covered despite their stormwater impact. As EPA evaluates different approaches to redefining MS4 boundaries, a more relevant definition of “urbanized” based on the extent of impervious surfaces would better target any categories of sources that are contributing pollutants to our waters. Such a shift would more equitably focus regulatory programs and requirements on actual stormwater dischargers rather than on communities chosen just because of their population and population density, creating incentives for sprawl development.
Fundamentally, stormwater runoff must be reduced by limiting the effects of the impervious surfaces that accompany development of new businesses and neighborhoods. Retention standards that drive green infrastructure approaches will diminish the impacts of new development and redevelopment, but we must also take significant steps to restore hydrologic functions to our heavily paved and built-out urban neighborhoods. One bright spot in the US Geological Survey study is that it’s never too late to restore urban streams, even at their most degraded. The restoration potential for urban streams across the country underscores the urgency to retrofit our cities for cleaner water.
Communities across the country are starting to realize the water-quality and economic benefits of integrating green infrastructure practices into their transportation and other capital projects during planned renovations or repairs. Both Olympia and Kirkland, WA, for example, integrated green infrastructure into capital improvement planning for transportation retrofits, providing cost savings and yielding greater water-quality benefits. Opportunities to incorporate smarter stormwater management approaches exist in all cities. Our work with Grand Rapids to pilot a “green infrastructure portfolio standard,” analogous to renewable energy portfolio standards, is just one way to systematically identify and plan for these changes. In addition to saving money, integrated capital planning should also open new sources of funding, like transportation investment, for clean water purposes.
At its core, updates to the municipal stormwater program that incorporate these principles will cost-effectively benefit clean water. But the multiple benefits created by increasing the use of green infrastructure have been shown repeatedly, making these approaches even more valuable for creating vibrant, more sustainable, and more climate resilient communities. Green infrastructure reduces localized flooding and energy use, improves public health and air quality, and provides a number of ancillary benefits to communities. As just one example, a watershed district in St. Paul, MN, used green infrastructure to solve a local flooding problem and achieve water-quality goals at a cost savings of $1 million, a 45% reduction compared to conventional techniques.
The Clean Water Act provides the critical framework to protect and restore the nation’s waters. The law’s emphasis on technology-based standards has driven innovation in places like Philadelphia that lead the way, using a suite of innovative green infrastructure approaches to reduce stormwater and sewer overflows. Washington, DC, is using its strong retention standard to create a local, volume-based trading program that will create opportunities for private investment in stormwater management, potentially reducing local government costs.
EPA must seize this opportunity and build on the progress that has been achieved in the sciences and at the local level, and propose reforms to the municipal post-construction program that move us to clean water and healthy communities.
