Regulatory Drivers of Green Infrastructure

Why do we have green infrastructure? Is it simply a better way to manage stormwater in our cities – or are do regulatory drivers relating to stormwater discharges encourage its use? What are the impacts of our federal regulatory structure on market demands?

All of these questions are related.

If you live in a medium-sized city or town, you likely have seen the increased use of green streets and green infrastructure over the last 10 or so years. There is a reason for this, but to really understand the reason why, and how this came to be, a brief historical recap of water quality in the United States is needed.

First, let’s take a step back to 1969, when the Cuyahoga River caught on fire in Ohio. Nothing like water catching on fire to draw attention to the disastrous condition of our nation’s water resources. This incident brought about a policy discussion of what to do to clean up our surface waters and protect water quality and aquatic habitats going forward. The Clean Water Act was passed in 1972, which gave authority to the U.S. Environmental Protection Agency (U.S. EPA) to regulate pollutant discharges to waters.

U.S. EPA began implementation of the Clean Water Act under the National Pollutant Discharge Elimination System, or NPDES. NPDES requires polluters to obtain and manage a permit for their discharging activities. At the time it was first introduced, NPDES permitting was only for wastewater treatment facilities (MWWF) and industrial operations discharging directly to U.S. waters.

It was not until 1990 that stormwater runoff became regulated under Phase I of NPDES. Phase I applied to communities with populations of more than 100,000 people that also had municipal separate storm sewer systems, or MS4s. (The MS4 distinction is important because many older cities in the Northeast and Midwest have combined sewer systems, which are regulated differently under the Clean Water Act through the National Combined Sewer Overflow (CSO) Control Policy implemented in 1994.)

Phase 1 communities must now obtain and manage their own NPDES permit to discharge stormwater from municipal infrastructure. In 2005, under Phase 2, NPDES was expanded to include cities and towns with 50,000 or more people. Also included under Phase 2 of NPDES are counties, individual state departments of transportation, and other large landowning or “stormwater producing” entities. For example, North Carolina State University, where I work, maintains its own Phase 2 NPDES permit separate from the City of Raleigh, which maintains its own Phase 1 permit.

The requirements and stipulations of each NPDES permit vary on a case by case basis, and each state’s environmental agency is responsible for administering the NPDES program, though U.S. EPA does retain the right to audit and review the permitting process of the states. One of the requirements included in all NPDES permits is that permittees must reduce pollutants in discharges to the “maximum extent practical.” But what does that really mean? Similar to many other administrative laws, the text is vague and the answer is: it depends.

It depends because each permittee is different and the severity of their water quality issues can vary greatly. In general, NPDES permit holders must show that they are actively taking steps that will decrease the amount of pollutants they discharge from their stormwater pipes to our streams, rivers, lakes or bays. There is a real financial cost to this, and many large cities have entire municipal departments dedicated to managing their NPDES permit. The most common method for funding these efforts at the municipal level is through an annual or monthly stormwater utility fee that all residents within the municipality are subject to.

Thus, we have the incentive for the use of green infrastructure to control stormwater runoff volumes and provide water quality treatment through innovative approaches. As green infrastructure approaches have developed and improved over time, numerous peer-reviewed studies have documented that they are a viable method for managing stormwater in cities, which helps NPDES permittees reduce pollutants in discharges that stated “maximum extent practical.” This regulatory structure creates a regulated market with demand for technical service providers like land surveyors, landscape architects, and water resources engineers – as well as new products to help NPDES permit holders meet the requirements outlined in their permit.

Nearly all public infrastructure – roads, water, sewer, energy generation, roads – is regulated on some level, which creates demand and opportunity for businesses help public entities with compliance.  Stormwater is a somewhat unique scenario in that it allows private citizens and businesses to develop solutions to the very public issue of water quality. As a water resources engineer, I recognize this first hand. I am certainly someone who has benefitted from the regulated market demand to improve and protect the waters of the U.S., from both an employment perspective and through recreation and enjoyment of clean water resources. It’s a critically important challenge; it will take cooperation on all sides in order to meet it.


Jonathan Page is an Extension Engineer at North Carolina State University where he specializes in water resources engineering and ecological restoration.

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