Improved representation of floodplains and natural features for channel routing in the national water model
Floodplains play an important role in the attenuation of floods, influencing river forecasts and flood inundation predictions, but they are poorly represented in the National Water Model (NWM). This project aims to improve our understanding and modeled representation of the influence of floodplain-channel connectivity on flood celerity and flood routing processes. We will develop an approach to characterize and classify floodplain types based on their unique impact on flood attenuation, test these characterizations with hydrodynamic models and verify them by field sensors. Modified hydrologic and hydraulic channel routing algorithms will be parameterized to capture complex floodplain topography and associated hydraulic processes. A prototype heterogeneous routing scheme will be developed that assures proper representation of process while optimizing computational efficiency. We will demonstrate improved performance of river stage forecasts and inundation predictions for the Northeastern US and explore the applicability of classified floodplain types outside of the region. Products developed through this project will be helpful for the National Water Center (NWC) and its partners (e.g., USGS) in the development of the Next Generation Water Resources Modeling Framework (NextGen) and geospatial data that support national hydrologic modeling applications.