CAREER: Flood Attenuation as an Ecosystem Service: Does it Scale Upward through Catchment-Scale River Restoration?

Floodplains provide an important ecosystem service of attenuating downstream flood magnitudes by slowing flow velocities as water moves across floodplain surfaces. In a sense, floodplains are a natural infrastructure that protect human development within a river basin. Unfortunately, rivers and floodplains have been extensively altered around the globe, largely due to engineering efforts to restrain the dynamic nature of river systems, through the construction of levees, dams, and other flood control measures.

Unfortunately, these river engineering projects have likely increased the risk of flooding due to loss of natural flood reduction services provided by floodplains. Flood attenuation may be improved, however, by implementing river restoration at large scales, though gaps still remain in understanding of how strategically dispersed restoration, river-floodplain interactions, and characteristics of river networks can enhance the ecosystem service of flood attenuation.

This research focuses on building fundamental knowledge of these interactions through a combination of field studies and modeling efforts that examine how human risk to flooding can be reducing while improving floodplain ecosystem services. This project includes an integrated research and education program aimed at mentoring first- generation students, increasing public exposure to river science, and redeveloping and disseminating undergraduate and graduate curriculum to include concepts of sustainable river-floodplain engineering and management.

This research will enhance understanding of how flood attenuation is regulated by both the structure of a river network and the physical characteristics of floodplain environments. The complex cross-scale dependencies of catchment configurations (large scale) and physical floodplain characteristics (small scale) in controlling flood movement through a river basin is still not understood.

This research will investigate the importance of catchment-scale restoration, river-floodplain interactions, and the organization of river networks in enhancing the ecosystem service of flood attenuation, which together comprise the foundations of natural flood management. The principal intellectual outcomes of this work will include: 1) a new cross-scale conceptual model describing the relationships between river network structure, floodplain characteristics, and degree of flood attenuation; 2) advanced understanding about the role of catchment-scale river restoration in sustainable water resource management and the strengthening of floodplain ecosystem services; and 3) a novel hydrologic modeling framework that can be used to generate transferrable knowledge about the impacts of river restoration strategies on large-scale floodplain ecosystem services.

This research will provide greater insight into how society can harmoniously blend the benefits of river restoration and natural flood attenuation within river catchments. In addition, the model developed potentially may be incorporated into the National Water Model, which is used by the USGS to monitor flooding around the nation. This project will positively impact engineering and river science education by supporting the success of first-generation students at Colorado State University, introducing youth to river science with a placed-based curriculum, and integrating research results into all education and outreach components of this project.

The project will support the involvement of multiple first-generation students through the Scott Undergraduate Research Experience program at CSU. Similarly, this project will expand the Girls Advancing Scientific Progress summer program and promote interest in river science through place-based learning. Field data collection and river monitoring activities in this project will be incorporated into two courses that will be redeveloped, enabling students to learn data collection methodologies, modeling approaches, and the importance of supporting catchment-scale river processes in water resources management.

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.