Science Wednesday: Going with the Flow – Does Stream Restoration Work?

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

About the Author: Erich Hester recently finished his Ph.D. in the Ecology Curriculum at the University of North Carolina at Chapel Hill. His research was funded in part by an EPA Science to Achieve Results (STAR) Graduate Fellowship.

Most Americans live in urban areas or their suburban fringes, and many more live near forests or agricultural lands. As kids, many of us enjoyed splashing in streams in our backyards or in the park down the street. Although we probably did not know it, major changes were occurring in those streams during our lifetimes because of human activities such as urbanization, agriculture, and even climate change.

Streams and rivers are important for humans, and not just for kids. They provide what are known as “ecosystem services,” such as supplying drinking water and rendering nutrients and toxins less harmful. But the capacity of aquatic resources to provide these services is being overwhelmed in many places.

To address these issues, billions of dollars are currently being spent on “stream restoration.” Nevertheless, the science connecting restoration practice to ecological recovery and ecosystem services is often weak, and many restoration projects fail to achieve their stated goals. I’m trying to fill scientific gaps between restoration design and ecological response so restoration projects can have a more positive impact on stream ecosystems, a goal shared by EPA scientists.

Through modeling and field studies, I evaluated how humans impact the exchange of water between streams and groundwater, which is critical to many stream ecosystems. I focused on how certain natural stream features, often used in stream restoration, can help restore surface to groundwater exchange. One key component of this exchange is heat, as temperature is the single most important condition affecting the lives of organisms, and humans can induce heat stress in aquatic organisms by warming the water. I determined how these features can help moderate peak temperatures in streams that are overheating due to deforestation or climate change.

This information will help improve design guidance for stream restoration currently being developed. I’m also participating in the Virginia Stream Alliance, a working group created by the Virginia legislature to foster knowledge transfer among academics, consultants, and government about the fast changing field of stream restoration.

I plan to continue research on this and related themes when I become an assistant professor in Civil and Environmental Engineering at Virginia Tech in January 2009.