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Science Wednesday: Protecting Water Quality in Metropolitan Areas

2008 December 31

Each week we write about the science behind environmental protection. Previous Science Wednesdays.

About the author: Tracy Hadden-Loh is completing her Ph.D. at the Department of City and Regional Planning, University of North Carolina at Chapel Hill and is looking forward to a career that will provide communities with more and better tools to plan for the future. Her work is funded by an EPA Science to Achieve Results (STAR) Graduate Research Fellowship.

Many of America’s streams, rivers, and lakes are not clean enough for swimming or fishing. In the past, much of the nation’s water quality problems were caused by industrial and municipal dumping. Thanks to the Clean Water Act, however, many of these sources of pollution have been greatly reduced.

So why are America’s urban rivers still not swimmable and fishable?

The answer is that every time it rains, the streets and rooftops of developed areas are washed clean by the downpour. All that water has to go somewhere. Stormwater runoff carrying loads of various contaminants has been the top water quality problem in the U.S. since 1994.

One strategy for dealing with polluted stormwater runoff has been to keep it from flowing too far—using devices such as rain barrels, retention ponds, green roofs to catch, slow down, and treat it. While these engineering devices help a great deal, they apply to small, distinct points across watersheds that are spread out over large regions.

That’s where my work comes in.

I am building a computer simulation of urban development and hydrology in Mecklenburg County, North Carolina (the home of the city of Charlotte) in order to explore how different regional urban forms of development could impact future water quality.

Rapid urban growth and its environmental consequences are a big concern in many American communities. I hope my work will help local decision-makers understand the tradeoffs involved with different policy directions.

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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11 Responses leave one →
  1. Brenda-EPA permalink
    December 31, 2008

    Sounds like an interesting program and much needed!

  2. Linda permalink
    December 31, 2008

    Good luck in your work. The impacts of urbanization are often much more severe than expected; your efforts may help reverse some of them.

  3. okbrooksby permalink
    January 2, 2009

    I have long thought that if the Environmental Protection Agency has enough government funding to find all these environmental problems then they should spend at least the same amount to find the solution to the problems. For every action their is a reaction and for every problem there is a solution. Call Me I am Available

  4. vicky permalink
    January 9, 2009

    I think the government should encourage/ or force companies, in any way they can, to limit packaging materials and to limit the manufacture of throw away items. e.g. disposable razors, toilet cleaners, etc.

    I think companies should think more environmentally. They convince people they can’t live without these disposable items by telling us how unsanitary it is not to use them. They need to remind people to be more environmental ……by not making them.

    Bottled water is one of the worst things ever invented. Stop production or make very sure everyone recycles bottles. We don’t need to drink water all the time….we never did in the past.

    Text book production is a big scam. Every year students have to buy the newest and the latest book rather than just add an addendum to previous version. What a waste of paper. Most can’t even be resold. GEt teachers and professors to standardize their text book choices and force the industry to comply.

  5. jessica permalink
    February 9, 2009

    It seems there needs to be some serious water conservation legislation enacted. I’m by means no fan of communism, but I think environmentalism is something that requires more of a socialist approach with much government intervention. The playing field is not level for technologies that support environmental conservation.

    Check out this information I found concerning water conservaiton at:

  6. Kevin Sparkman permalink
    February 15, 2009

    Florida Department of Environmental Protection has recently produced two valuable web resources on watershed protection. The first is Florida’s Water: Ours to Protect at, which includes multi-media stories about a range of water protection and river basin restoration programs. The second is Florida-friendly Landscaping at, which is popular site with in-depth information about low-impact landscaping practices. This site includes an interactive yard, comprehensive “Florida-friendly” plant database, tutorials and more. Take a look and share with your colleagues.

  7. amy permalink
    March 10, 2009

    I was surprised that even temperature is considered a pollutant with stormwater. The water on parking lots is warmed by the concrete and discharged into the nearest creek, which effect the temperature there, which in turns effects the dissolved oxygen content! Wow, everything we do can effect the environment. Check out where I read this:
    they had all kinds of interesting stuff!

  8. December 3, 2009

    “So why are America’s urban rivers still not swimmable …?”

    Because a couple of the underlying assumptions are faulty.

    An urban “stream” often doesn’t have enough water in it to immerse a human head during dry weather, and would kill a swimmer by drowning or bashing his or her head against the walls during wet weather.

    Yet most “impaired waters” lists insist that urban drainage channels aren’t “swimmable” because of the presence of fecal coliform bacteria in stormwater.

    News Flash from EPA, 1989: Fecal coliform is NOT a pathogen. It is not even a valid indicator of pathogens.

    Yet, everybody keeps calling the streams that carry any type of this group of naturally-occurring bacteria “impaired” for “pathogens.” And they bemoan its presence in waters under conditions where no swimming occurs.


    Its cheap, its easy, and there’s lots of historic data that we can “use” to determine “trends.”

    “Where attainable” got lost somewhere along the way, as did “existing use”

    Until the underlying false assumptions are corrected, we will continue to spend money and effort trying to fix the “impairment” that defines urban “streams” to not be “swimmable.”

  9. james permalink
    March 17, 2010

    Sounds like an interesting study, did you hear about the study which was similar.

  10. Jon permalink
    January 26, 2011

    Good luck in your work.

  11. Jon permalink
    January 26, 2011

    I’m by means no fan of communism, but I think environmentalism is something that requires more of a socialist approach with much government intervention.

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