urban development

Studying Stream Restoration

By Marguerite Huber

Stream running through a lush, forested landscape

Forested stream

When I was younger, there was a prairie and stream behind my house. I ran and played there all the time with my friends until a house was built in its place. The lot was transformed from a wild, overgrown landscape to a manicured lawn. With the prairie gone and stream no longer enticing our adventures, we stopped playing there.

When homes and roads are built, they affect the habitat, quantity, and quality of water in downstream ecosystems (as well as natural places for kids to play!). Additionally, it causes an increase in nutrients like the fertilizer from that manicured lawn, and sediments, metals, and other pollutants making development a leading factor in stream impairment.

Local communities are increasingly turning to engineered techniques intended to reduce or eliminate the impacts of development on streams and other aquatic ecosystems. But do such efforts work?

Stream running through an urban area

Urban stream

EPA scientists Naomi Detenbeck and Nathan Smucker set out to evaluate how well “out-of-stream” restoration actions (those actions that take place in the watershed as opposed to within streams) work and to identify any general trends found in the scientific literature. They examined the response of water quality, habitat and hydrology, and ecological structure and function to development and restoration.

The scientists used statistical analysis to identify more than 40-years’ worth of published scientific literature on effective ways to protect streams from the unintended impacts of activities that harm streams. Starting with more than 1,400 papers, they pared it down to thirty-eight that covered forty-four restoration projects.

Smucker and Detenbeck found that the projects covered a number of stream restoration actions such as riparian buffers, human-made wetlands, and stormwater ponds. The projects looked at the bigger picture of managing streams by focusing on their watersheds. These “out-of-stream” approaches are important because efforts that have focused solely on habitat restoration within streams have had limited success.

Pooling together data from all the papers, the researchers found that biodiversity was reduced by more than half in unrestored urban streams and measures of things such as reducing erosion, nitrogen fixation, and other ecosystems services were significantly greater in restored streams than unrestored.

Even if it is impossible to fully restore streams, preventative actions can still be taken to protect downstream ecosystems in watersheds that are facing future development. In addition, tracking restoration projects (like the ones used in the studies) and ongoing monitoring would benefit future efforts to protect, restore, and manage streams.

Knowing what works and what doesn’t can help government agencies, policymakers, and citizens recognize and evaluate potential environmental outcomes resulting from their actions and decisions. It can also aid in setting restoration goals, prioritizing sites to monitor, and guiding future decisions and development as populations continue to grow.

About the Author: Marguerite Huber is a student contractor with EPA’s Science Communications Team.

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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Insects as Indicators

By Marguerite Huber

Twelve spotted skimmer dragonfly perched on a reed.

Twelve-spotted skimmer. Image courtesy of the U.S. Fish & Wildlife Service.

Scientists have developed ways to use certain species as kinds of “living barometers” for monitoring the quality of the environment. By studying the abundance, presence, and overall health of such indicator species, they gain insight into the general condition of the environment. Now, EPA researchers are developing ways to use insects in this way to explore the effects of environmental contamination and how it might spread across a watershed.

The Superfund program, established by the Comprehensive Environmental Response, Compensation and Liability Act, identifies sites that contain hazardous substances, such as pollutants and contaminants, that may pose a threat to human health or the environment.

Superfund sites include former landfills, industrial and military complexes, and abandoned mines.

In their study, EPA researchers sought to determine if insect communities could be used to measure the benefits of Superfund site clean-up and to monitor the effectiveness of site remediation and restoration. To be accurate, they also had to account for the differences between impacts from Superfund contaminants, and those related to urbanization.

The researchers compared a number of indicators related to urbanization, such as land development, housing unit density, and road density.

In the end, the researchers found that once they had accounted for the effects of urban development, they were able to use insects as indicators for detecting the effects of Superfund sites in the watershed. Using what they learned from that work, they also developed models that can discriminate the effects of Superfund activities from those of development upstream, and help identify those streams where impacts exceed what would be expected based solely on the amount of development across a watershed. Researchers and others can also use the models to assess the effectiveness of remediation efforts at contaminated sites.

Overall, developing methods to tap insects as indicators is helping EPA researchers understand how Superfund sites affect entire watersheds. It’s a big step toward cleaning them up and helping EPA fulfill its mission of protecting human health and the environment.

About the Author: Marguerite Huber is a Student Contractor with EPA’s Science Communications Team.

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.