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Researchers propose new framework to improve water quality and protect infrastructure
RESEARCH TRIANGLE PARK, N.C. – An interdisciplinary team of researchers from, North Carolina State University, RTI International, Visa, Inc., the University of Minnesota and the University of Maryland has developed a suite of tools to estimate the total economic value of improving water quality in urban streams. The work can assist federal and state agencies with developing environmental regulations affecting urban ecosystems across the Piedmont Region of the United States, which stretches from Maryland to Alabama.
“We’ve shown that this approach can work, and it is designed for use in urban areas throughout the Piedmont region,” said Roger von Haefen, professor of agricultural and resource economics at NCSU and co-author of the paper. “Currently, EPA has limited tools to assess the benefits associated with environmental regulations that affect urban streams. We are optimistic that federal and state agencies can use this framework to better capture those benefits and make more informed regulatory decisions.”
“Use” benefits arise from how people directly interact with urban streams. For example, attractive streams can increase property values of nearby homes, whereas polluted streams may diminish property values. “Non-use” benefits capture existence and bequest values, or what people are willing to pay to protect natural resources in their natural state for the benefit of future generations.
The suite of tools is described in a new paper titled “Estimating the Benefits of Stream Water Quality Improvements in Urbanizing Watersheds: An Ecological Production Function Approach,” which highlights the research team’s “ecological production function framework” that draws on existing water quality monitoring data and uses computational modeling to predict water quality changes related to various regulatory interventions. The framework then leverages expert assessments of how the public will value these water quality changes. A survey of area residents is used to quantify their willingness to pay for these outcomes – and, by extension, for improvements in stream water quality.
The researchers demonstrated the new benefit estimation tools by looking at the Upper Neuse River Basin in Durham and Wake counties in North Carolina. They found that residents of the area would be willing to pay an average of $127 per year – approximately $54 million in total – for water quality improvements derived from increasing tree cover along stream banks by 25% and decreasing runoff from impervious surfaces, such as streets and parking lots.
“As urban populations grow the ecosystem services provided by these streams are increasingly threatened by the effects of economic development, including high rates of sediment erosion and surface runoff,” said George Van Houtven, Ph.D., ecosystem services research director at RTI and co-author of the paper. “Now new tools can help with estimates of the combined use and non-use benefits of improving urban stream water quality, which are critical for guiding policy.”
The paper was published in the Proceedings of the National Academy of Sciences (PNAS).
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