A new study has found that widely used techniques to assess the health of freshwater streams are not effective at detecting a variety of water quality issues, including issues related to acidity, oxygen levels, and the presence of pathogens.
This research began as a class project, with many of us learning about a health assessment methodology called the Stream Visual Assessment Protocol (SVAP) as ecology students. The goal of this project was to assess the health of regional urban streams using both SVAP and laboratory-based water quality testing. We also found that there was a large discrepancy between SVAP scores and water quality test results. ”
Abigail Finch, co-author of a journal article about this study and former undergraduate student at North Carolina State University
SVAP was developed by USDA’s Natural Resources Conservation Service to serve as an accessible method for resource managers and the public to obtain a “snapshot” of general river health. SVAP involves assessing a variety of visual features, such as water appearance, the presence of invertebrate habitat, and deep spots (or pools) in the river. This methodology is used in the United States and internationally as a tool to assess freshwater stream conditions.
For this study, the research team used SVAP to assess flows in four cities. The researchers also used equipment to collect quantifiable data on each river’s physical characteristics and water quality parameters. Physical characteristics include water depth and water temperature. Water quality parameters include measurements such as dissolved oxygen concentration and testing. Enterococcuswhich is a fecal indicator.
The researchers found that SVAP scores were strongly correlated with measured physical characteristics, but there was little significant correlation between SVAP scores and water quality data.
“There were no visual markers associated with most water quality characteristics,” says study lead author Erin McKechnie, assistant professor of applied ecology at North Carolina State University. “Dissolved oxygen concentration, pH, presence or absence of oxygen” Enterococcus are all important water quality criteria, and SVAP does not provide information on their characteristics. ”
However, researchers found that there are several SVAP components that correlate with several water quality characteristics. Specifically, water appearance was related to total dissolved solids and conductivity. And physical changes in riverbanks were associated with turbidity.
“This suggests that while SVAP is not sufficient to measure river health, this protocol may have real value in identifying urban rivers that could benefit from restoration efforts to reestablish ecosystem services, such as establishing riparian vegetation that can limit erosion and act as riparian buffers to filter pollutant runoff,” McKenney says. “In the long term, restoring these ecosystem services can have a major impact on river health.”
“Riparian buffers can also reduce the effects of flooding, which is a huge advantage in urban environments,” says Finch.
“But the takeaway here is that while SVAP may be helpful, water quality testing is still needed to accurately assess the actual health of the river,” McKechnie says.
sauce:
north carolina state university
Reference magazines:
McMurray, C. others. (2026). Evaluation of river visual assessment protocols using measured water quality parameters in urban rivers. Pro Swan. DOI: 10.1371/journal.pone.0351972. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0351972
