Science Wednesday: Protecting Water Quality in Metropolitan Areas

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.