combined sewer overflows (CSOs)

Fresh and Clean, or Fresh and Green?

by Matt Colip

O Street NW, in DC, was revitalized to control stormwater  with 33 individual rain gardens built with native plants.

O Street NW, in DC, was revitalized to control stormwater with 33 individual rain gardens.

I’ve always enjoyed walking along new city streets.  The sidewalks are crisp and clean, free from chewing gum and spill marks.  There are no chassis-rattling potholes in the road.  It’s reminiscent of the new car feel, everything seems minted.

In Washington, D.C., and a growing number of communities in EPA’s Mid-Atlantic Region, residents and businesses are getting a bonus when it comes to new road construction – green features to control stormwater runoff.

The nation’s capital, like many older cities in the United States, is faced with the perpetual challenges of revitalizing streets and managing a combined sewer system that mixes stormwater and sewage into large underground pipes that feed the wastewater treatment plant.  The challenge for city governments is that residents want the fresh and clean feel on their streets, and a guarantee that their sewage will reach the treatment plant and not overflow into a river because too much stormwater has flooded the system.  To meet these demands, the District, under the leadership of Mayor Muriel Bowser, has chosen to build fresh and clean streets that are also fresh and “green.”

I accompanied our EPA Regional Administrator, Shawn M. Garvin, recently as he helped cut the ribbon for one of the District’s newest green street projects – this one along the 200 block of O Street NW, a street that has been closed to traffic since 1977.

In addition to integrating green infrastructure into street rehabilitation, the revitalized O Street now includes 33 individual rain gardens along the sidewalks that are landscaped with native plants. These rain gardens capture the runoff from an area 5,732 square feet in size – about 20% bigger than a standard basketball court – and keep the water out of the sewer system.  Rainwater and sewage that flows into this part of the District’s sewer system risks overflowing into the Anacostia River.  The more stormwater that is diverted from the combined sewer system, the less likely an overflow will occur into the river.

Not only does O Street now capture rainwater, it will have a new tree canopy from the trees planted street along its sidewalks.  These trees will also slurp up stormwater, keeping it from entering the sewer system, and eventually provide shaded areas.  This shade will reduce the heat island effect of the black asphalt.  Overall, the street looks great!

This work was funded in part through the U.S. Environmental Protection Agency’s Green Streets, Green Jobs, Green Towns (G3) initiative, a program administered by EPA and the Chesapeake Bay Trust. The green infrastructure approach of the partners in this project – the District’s Departments of Energy & Environment, Transportation, and General Services – supports the G3 program goals of improving water quality, community livability and economic vitality.


About the author: Matt Colip is a state and congressional liaison in the region’s Office of Communications and Government Relations. He previously worked in the region’s water programs, enforcing wastewater and stormwater regulations. In addition to SCUBA diving, Matt is an avid bicyclist and enjoys riding with friends and colleagues.


Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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Challenges and Combined Sewer Overflows

By Ryan Connair

sewer overflowing

Overflows happen when combined sewers are overwhelmed by heavy rain.

Every year, combined sewer overflows (CSOs) release about 850 billion gallons of untreated sewage and stormwater into lakes, streams, and rivers across the United States. CSOs happen when combined sewers—which carry both stormwater and raw sewage—are overwhelmed by heavy rain and flow into local waterways.

Unfortunately, this situation is hard to fix. Sewer utilities have thousands of miles of pipes to manage, so they often lack the resources to continuously monitor CSO activity or precisely measure how much wastewater is being discharged into the environment.  A low-cost, wireless sensor could change all that, though.

To find such a sensor, EPA partnered with Confluence—a water technology cluster in the southwest Ohio, northern Kentucky, and southeast Indiana area—to issue an open innovation challenge. Open innovation challenges offer awards for solutions that address a problem and draw in the best ideas from around the world.

The challenge was issued in July 2013 through Cincinnati Innovates and InnoCentive, who recently announced the winners.

First prize of $6,000 was awarded to Krishna Priya, from India, with prizes of $2,000 each going to Tamus Szalay (USA) and Andre Villemaire (Canada). Priya’s winning solution combined water level and ultrasonic sensors with a cellphone radio to create a prototype device that monitors water level and flow. During a CSO event, the system can send data back to utilities via text message.

“Real-time information provides the ability to plan for the events, respond quickly to equipment malfunction, and assure control systems are operating properly,” said Melissa Gatterdam, Superintendent of Watershed Operations at the Metropolitan Sewer District of Greater Cincinnati (MSDGC).

But the challenge goes beyond identifying a winning idea, it also involves a community. In this case, the community is Greater Cincinnati. Two local utilities—MSDGC and Sanitation District No. 1 of Northern Kentucky (SD1)—and a local branch of the technical consulting firm Stantec provided judges for the contest. The two utilities have expressed interest in testing the prize-winning ideas identified by the competition.

“EPA has displayed exceptional leadership with this challenge, which has catalyzed the difficult process of transferring new ideas into new technologies that are ready for the marketplace,” said Chris Kaeff, Regulatory Reporting and Wet Weather Coordinator for SD1.

“The public utility stands to gain new technology that improves operational efficiency,” Kaeff said. “The entrepreneur gains a pathway to impact the market. The venture capitalist gains an opportunity for investment. And the federal regulatory and research agency moves closer to its goal of ensuring compliance.”

Partnering to issue the challenge, EPA was able to accomplish two goals: the challenge identified a solution to a pressing environmental issue and connected the winners to utilities who can put their ideas into practice by serving as test beds for the technology and potential buyers in the market for the finished solution.

About the author: Ryan Connair works with EPA’s Environmental Technology Innovation Clusters Program as a communications contractor.

Editor’s Note:

Read more about EPA research exploring ways to reduce stormwater runoff and combined sewer overflows:

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.