NSF Award
1748816
The project will address the complex ways in which extreme floods impact river channel formation and stability and the structure and composition of related riparian forests. Previous studies of flood effects on river systems have focused on the history and causes of the flood, and their hydrology, with little attention to the flood impacts on riparian forest structure and the consequences of woody debris inputs on channel stability. Furthermore, the few studies that do exist have been limited to mountainous or arid regions, and their findings of limited applicability in more humid settings. More studies examining the variation of flood disturbances among different regions and within watersheds are needed to evaluate the long-term influence of floods on channel form, sediment, and forest structure, and to help predict how flood impacts can be managed in the future. The results of this study will help address U.S. Forest Service concerns over future impacts of increased flooding trends on federal facilities and the natural resources of national forests. The findings of this study will be shared during a workshop with the U.S. Forest Service, Department of Transportation, and surrounding communities. Besides benefits for natural resource management, this project will provide educational opportunities for undergraduate and graduate students in fieldwork and data analysis through the Ozarks Environmental and Water Resources Institute (OEWRI) at Missouri State University.<br/><br/>The goal of this project is to describe and analyze how an extreme flood (greater than a 100-year return interval) has contributed to riparian forest mortality and wood recruitment along the river channel, and to identify which variables are responsible for the spatial variations in those effects. The research plan addresses five questions: (1) Was riparian tree mortality systematically related to biological variables (e.g., species, size of trees, pre-flood wood patterns)?; (2) Was mortality systematically related to hydro-geomorphic variables (e.g., valley morphology, landform, flow depth)?; (3) How much woody debris was generated and what tree or site characteristics affected the likelihood of wood transportation versus accumulation?; (4) Do forest disturbance and wood debris patterns vary with scale at different sites along a gradient of increasing drainage area?; and (5) Can aerial imagery from drones/UAVs and photogrammetry-based analysis be used to acquire accurate quantitative data regarding tree mortality and wood accumulation? This study combines field research with imagery analysis to evaluate the effects of the largest flood on record on the North Fork River in the Missouri Ozarks. The results will be combined with those from other regional studies to develop a conceptual model of geomorphic-biotic response to extreme floods in a humid forest environment. While this study focuses on the assessment of immediate effects, it will offer insights into the spatial variability of those effects and the direction of recovery which can be monitored over the next decade or longer to gain a full understanding of the recovery process. The research will inform fundamental understanding of fluvial geomorphic and biogeographic processes.
