Dec. 17, 2013. Stream restoration projects have become a multibillion dollar industry. But do projects always yield the desired results or can they create a false image of stream and landscape protection?
That’s a question Appalachian State University faculty members Kristan Cockerill and Bill Anderson posed when they studied four restoration projects along Boone Creek, a stream that runs through campus and the Town of Boone.
Their findings were published in the Journal of the American Water Resources Association on an article titled “Creating False Images: Stream Restoration in an Urban Setting.”
Anderson is department chair and a professor in the Department of Geology. As a hydrogeologist, his research interests include groundwater and surface water interactions and the role groundwater discharge plays in controlling stream temperatures and stream salinity.
“Stream restoration often focuses on restoration of the stream channel without thinking of the broader problems that may be affecting the stream from the entire watershed,” Anderson said.
“In the case of Boone Creek, this means urbanization, such as impervious surfaces and storm water networks, which is leading to increased flows and heated runoff. Restoring the channel doesn’t address these problems, which will continue to exist after the restoration and may quickly undo the so-called restoration.”
Cockerill said a disconnect between a project’s stated purpose and its actual outcomes can happen when insufficient data is collected prior to beginning a project, or when only one issue related to stream quality is considered.
She and Anderson chose Boone Creek, which is classified as a trout stream, for their case study because of the volume of pre- and post-mitigation data that had been collected since 2006 from three of the four restored creek segments.
The project focused on improving water quality and stream ecology, including the need to reduce sediment and improve the habitat. Several projects received state funding because of the focus on improving water quality, the professors wrote in their paper. However, data they analyzed pointed to problems not addressed or mitigated by the restorations, such as stream temperature, or that didn’t exist in harmful levels such as sedimentation.
“Temperature has been the most significant ecological issue on Boone Creek and these restoration projects have done little to address this,” the authors wrote.
“There is a general lack of communication between researchers and those who implement restoration projects,” Cockerill and Anderson wrote in their paper. “This disconnect is well represented in research showing that despite the less than overwhelming evidence that ecological conditions can be improved, especially on urban streams, stream restoration project managers do report that their projects are successful.”
The professors also wrote, “In these cases, success is based on receiving positive public response and the general observations of the restored site rather than on specific monitoring data about ecological conditions.”
There are many factors to consider when initiating a stream restoration project that reaches beyond esthetics and recreational value, Cockerill explained.
“Hydrologists are going to look at the water flow, geologists will look at the morphology and physical structure of a stream,” she said. “Biologists are concerned with a stream’s or waterway’s ability to support aquatic life. Chemists are interested in a stream’s nitrate, phosphate and pH levels. So historically you may have looked at only one of these parameters and called that ‘the water issue.'”
Boone Creek is channeled through culverts in many locations as it flows to the South Fork of the New River. One section was opened in the mid-1990s primarily for a storm-water mitigation project on campus that was needed prior to construction on the university’s Holmes Convocation Center. A second benefit of that project was to create a park-like setting for visitors to enjoy.
In 2010, another section of the creek was stabilized to prevent undercutting of the street-side bank. But trees that once shaded the creek and had helped lower the water temperature were removed. Water temperatures along that section of the creek exceed temperatures conductive for a trout habitat, Anderson found.
Cockerill and Anderson wrote that while specific ecological goals might not have been met, the projects had helped reduce flooding in the area and prevented undercutting of a section of a street that runs through campus.
“We don’t want to imply that some aspects of these projects weren’t worthwhile,” Cockerill said. “I would argue that you have to be honest from the outset about what you are really trying to accomplish and then collect data appropriate to the goal.”