The influence of hierarchical and multiscale river morphology and sediment heterogeneity on hyporheic exchange processes

Solutes, heat, and other dissolved constituents interact along rivers as river water and groundwater mix, often referred to as hyporheic exchange. Processes within the hyporheic zone have the potential to mitigate contaminant loads in rivers and improve water quality. These processes depend on the shape of the channel and the distribution of sediment types and thus vary across space and time.

This project will combine innovative field measurements with advanced computer models to provide insights into the influence of sediment heterogeneity and river channel morphology on solute fluxes and nutrient cycling. Results of this research will have practical applications in water resource management, and will guide strategies to optimize both surface water and groundwater quality.

The project will use the Theis Environmental Monitoring and Modeling Site at the University of Cincinnati. Hands-on activities at the site will stimulate student interest, and prepare them for water-related STEM careers. A diverse group of K-12 students will receive hands-on experience through a water program developed in partnership with the Cincinnati Museum Center.

The project goal is to provide insights into how multiscale sediment heterogeneity and river channel morphology control hyporheic exchange processes, and to improve the capacity of numerical models to predict spatial patterns of hyporheic flux, solute residence times, and resulting biogeochemical transformations. The project will utilize innovative field observations to develop and validate multiscale numerical models.

The project will address several primary goals: (1) quantify the controlling influence of multiscale fluvial forms and associated stratal architecture on hyporheic flux and solute residence times, and determine the relevance of scales; (2) determine how multiscale fluvial forms and stratal architecture influence biogeochemical reaction dynamics within the hyporheic zone; and (3) identify which heterogeneity and morphologic attributes are most essential for understanding and accurately predicting hyporheic exchange processes.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.