Clean water is indispensable for human health, and human activity plays a large role water quality. West Virginia University researchers have compared that circular relationship in watersheds affected by different water movement and external factors to identify the dominant controls of stream water quality and ecosystem health.

Omar Abdul-Aziz, associate professor of civil and environmental engineering, and doctoral student Shakil Ahmed, conducted the research, quantitatively uncovering the roles of surface runoff vs. ground water, urban vs. agricultural land uses and draining watershed vs. external (e.g., coastal) drivers to determine the amounts of nutrients, biomass and dissolved oxygen in streams and rivers.

“We employed the concept of watershed similitude to combine the numerous drivers and parameters of stream water quality into a small set of entities,” Aziz said. “Process interpretations of these entities provided a generalized understanding into the dynamics and controls of stream water quality and ecosystem health.”

The research findings can guide water resource managers to achieve healthy stream ecosystems, as mandated by the U.S. Clean Water Act. Based on the knowledge of dominant controls, water managers can identify streams that are more vulnerable to pollution and set management priorities.

Various hydrologic, land use, biogeochemical and ecological processes shape stream water quality and ecosystem health. Identification of the dominant controls of stream water quality, as well as understanding their contrasting and collective roles, have been challenged by the multitude of pollutant sources, drivers and their interplays.

The research was published in a recent edition of the American Society of Civil Engineers’ “Journal of Hydrologic Engineering” and was funded by a CAREER grant awarded to Abdul-Aziz from the National Science Foundation.