water science

Around the Water Cooler: Keeping Stormwater In Place

By Lahne Mattas-Curry

Raining in the city

No where to run: stormwater has no place to go but the sewer.

In the first post of my series on EPA water research, I gave a little history lesson and introduced green infrastructure. This week, we’re going to focus on the cost of combined sewer systems—to our health, our environment and even our economy.

There are hundreds of cities across the country that have combined sewer systems. For example, in New York City, more than 27 billion gallons of raw sewage and polluted stormwater discharge out of 460 combined sewer overflows into the New York Harbor alone each year. Think about all the impermeable surfaces in the city: sidewalks, streets, roofs, patios. It’s a concrete jungle.

To manage stormwater—and set up scenarios to see the impact of development—EPA scientists are developing the Stormwater Calculator that estimates the annual amount of stormwater runoff from a specific site and provides city planners, developers, and property owners a way to calculate the result of specific actions on our waterways. The online tool will be available later this fall.

As stormwater flows over the surface of your property, driveways, parking lots, roofs, etc, it picks up lots of sediments, such as animal droppings, tire residue, motor oil, brake dust, deicing compounds (in the winter), fertilizers, pesticides, trash, heavy metals and other pollutants and carries them to the nearest storm drain.

Obviously, there are things that cities can do to help reduce stormwater run off, and the steep price tag that goes with the cost of separating the combined sewer systems.

For example, in Omaha, the city is testing green infrastructure throughout the city to help reduce the $1.7 billion sewer system separation project. EPA scientists are testing and monitoring soils in Omaha, and other cities such as Cleveland and Cincinnati, to measure how successful green infrastructure is at keeping the combined sewer overflows to a minimum.

City of Omaha

Cities like Omaha are looking for ways to use green infrastructure to reduce stormwater costs.

There are steps you can take too.

According to the University of Nebraska, for every 1,000 square feet of impermeable surface on your property, every 1 inch of rainfall generates approximately 626 gallons of water. If you add two 55 gallon rain barrels to your property, you now have water to irrigate your gardens. Add a rain garden, and you probably take care of much of the excess. Now, rain is absorbed back into our aquifers instead of rushing into the nearest storm drain, keeping waterways clean and ecosystems functioning.

Many states and counties subsidize the installation of green infrastructure on property, so check with your county and state government. It’s worth it to make sure we have clean water for generations to come.

About the Author: Known around the office as “AguaGirl,” Lahne Mattas-Curry works with EPA’s Safe and Sustainable Water Resources team and  communicates water research to anyone who will listen or read her blog posts.

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

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Around the Water Cooler: Leaving the Outhouse Behind

By Lahne Mattas-Curry

Stormwater flows from a large pipe.

Green infrastructure helps keep stormwater in place.

This week, and every Thursday that follows, I’ll introduce you to the EPA scientists and engineers who work to make sure our water stays clean and that we have enough for generations to come.

Today I’m kicking off a series on green infrastructure while we recognize the role of science and innovation in the Clean Water Act, which turns 40 this year.

What is green infrastructure? It’s actually just a fancy term for rain gardens, rain barrels and cisterns that keep excess water out of our storm drains.

But let’s start with some history. In the mid-1800s, flush toilets came to America. Everyone wanted one so that no one would have to make that nightly cold, dark trek to the outhouse. Soon, though, it became obvious that when you “flush” the toilet inside the nice warm house, the waste has to go somewhere. Initially that somewhere was our streets.

Thankfully, that did not last long.

Motivated by smelly city streets, municipalities added underground pipes to carry the wastewater from homes and businesses and deposit in waterways where it could be diluted and carried away in the current. The pipes, though, also carry stormwater that rushes off the streets during heavy rain.

Welcome to the combined sewer system.

There are approximately 800 cities and towns across America that still use combined sewer systems, including big ones such as New York and Chicago, and smaller ones like Omaha and Louisville.

Today, these systems don’t feed directly into our waterways. The water is first sent to a treatment plant where it is cleaned.

The problem with these combined sewer systems is that when it rains hard, the polluted wastewater doesn’t always make it to the treatment facility, and instead goes directly to our rivers, streams and other waterways. (A violation of the Clean Water Act. And also pretty gross.)

But changing out all these networks of pipes—called gray infrastructure—is costly. EPA scientists and engineers have been working with several municipalities around the country to find alternatives—innovative solutions to efficiently and inexpensively reduce runoff flowing into combined sewer systems.

Each Thursday over the next few weeks I’ll highlight green infrastructure research and best practices while sharing ways you can make a difference in your community.

In the meantime, check out this interactive tool from the Arbor Day Foundation to compare the difference between a community with increased green infrastructure in the form of more trees versus a community with less. Which would you rather live in?

About the Author: Lahne Mattas-Curry works with  EPA’s Safe and Sustainable Water Resources team, drinks a lot of water and  communicates water research to anyone who will listen.

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.