SGER: Iowa Flood Mapping by Airborne Laser Swath Mapping

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0848400ShresthaThe PI requests funding to overfly the Iowa River corridor to capture imagery of the 2008 Midwestern flood ? a potential 500 year extreme event. The overflights are scheduled for 19-21 June 2008 and will use airborne laser swath mapping to carefully analyze flooded areas in Iowa. The objectives are to interface the lidar-based map products with soil erosion models in order to determine sediment load provided to the watershed outlet (Gulf of Mexico), to refine estimates for total nitrogen washout from agricultural lands using both mapping and in situ measurements, to better understand drainage channel geometry in the flooded watershed, and to constrain the drainage channel hill slope morphology in order to refine water residence time modeling. The unique aspect of the proposed research is the ability to combine large-scale high resolution mapping technology to understand a rare (perhaps 500 year) flooding event. Using lidar mapping, the PI may feed geomophological data into large scale two-dimensional flood wave propagation models within the Iowa River watershed. In addition, high-resolution bathymetry data will be coupled with high-resolution free-surface maps in order to follow post-flood changes in the main channel morphology. Ultimately, the high-resolution mapping products will be incorporated into predictive models to assist managers at all levels, from civic planning to emergency response. The magnitude of flooding observed in Iowa demonstrated the limitations of current FEMA 100-year and 500-year flood maps, primarily caused by poor accuracy and resolution. High-resolution mapping will provide managers with the tools needed to model and understand the 2008 Midwestern flood and will provide a basis for better understanding river morphology. Data will also be useful in estimating nutrient loading to the Gulf of Mexico which may impact the dynamics of the dead zone. With billions of dollars lost each year, more accurate flood and geomorphology data are timely and of broad interest.***