H111-0018
Topobathymetric and Hydraulic Roughness Data Enhancements for National Water Model Coastal Module

Friday, 11 December 2020
Poster
Sadiq Khan1,2, Hassan Mashriqui3, Chris Amante4, Js Allen5, Fernando Renzo Salas5, Mark Glaudemans6 and Trey Flowers7, (1)University Corporation for Atmospheric Research, Boulder, CO, United States, (2)NOAA/NWS National Water Center, Tuscaloosa, AL, United States, (3)National Oceanic and Atmospheric Administration (NOAA), Office of Water Prediction, National Weather Service (NWS), Silver Spring, United States, (4)Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States, (5)NOAA National Water Center, Tuscaloosa, AL, United States, (6)NOAA, NWS Office of Water Prediction, Silver Spring, MD, United States, (7)NOAA/NWS Office of Water Prediction, National Water Center, Tuscaloosa, AL, United States
Abstract:
Accurate topographic and bathymetric representation in distributed hydrologic, hydraulic, and coastal modelling is a prerequisite for model accuracy. To date, there is no single seamless terrain and bathymetry dataset with coverage across the entire coastal domain of the National Water Model (NWM) that integrates terrain elevation, coastal bathymetry, and riverine bathymetry. The main goal of this effort is to develop a topographic and bathymetric database from several sources into a digital elevation database including a unified horizontal and vertical datum, to be used for coupled models in the inland coastal zone. In addition, a hydraulic roughness parameter database was developed, based on the National Land Cover Database (NLCD).

The workflow and processes associated with database creation include: a) review and processing of available topobathymetric digital elevation models (TBDEM) data, b) conduct quality assurance and quality checks of the topobathymetric data product and c) post-processing of the TBDEM to prepare the data for the D-FLOW model used in the coupled model. Topographic and bathymetric data was consolidated into a seamless TBDEMs dataset primarily from these sources: 1) the United States Geological Survey (USGS) Coastal National Elevation Database (CoNED) at 1 meter spatial resolution, 2) NOAA’s National Centers for Environmental Information (NCEI) data at 1/9 arc-second (3 meter) resolution, available through the NOAA Data Access Viewer (DAV) and Digital Coast.

Spatially variable Manning’s roughness coefficients were initially derived from literature review and further enhancements will be made using the available studies conducted by the United States Army Corps of Engineers (USACE), USGS and Federal Emergency Management Agency (FEMA). The current coastal model interpolates roughness values during the model initialization process to achieve the smooth transition of roughness values over the model domain. Initial sensitivity analyses of spatially variable hydraulic roughness parameters, based on tidal analysis outcomes, were conducted in order to achieve the best roughness configuration. The topobathymetric data and hydraulic roughness estimates for the Atlantic and Gulf of Mexico domains are ready for use in the coastal module of the NWM.

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