Dietsch, Benjamin J. Strauch, Kellan R. 2019 document Reston, VA U.S. Geological Survey https://doi.org/10.5066/P9B0XLJL Digital flood-inundation maps for a 11.0-mile reach of the Meramec River near Eureka, Missouri, were created by the U.S. Geological Survey (USGS) in cooperation with the United States Army Corps of Engineers, St. Louis Metropolitan Sewer District, Missouri Department of Transportation, Missouri American Water, Federal Emergency Management Agency Region 7, the City of Pacific, the City of Eureka, the City of Wildwood, and the City of Arnold. The flood-inundation maps, which can be accessed through the USGS Flood Inundation Mapping Science Web site at http://water.usgs.gov/osw/flood_inundation/, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the USGS streamgage on the Meramec River near Eureka, Missouri (station number 07019000). Near-real-time stages at this streamgage may be obtained on the Internet from the USGS National Water Information System at http://waterdata.usgs.gov/ or the National Weather Service (NWS) Advanced Hydrologic Prediction Service at http://water.weather.gov/ahps/, which also forecasts flood hydrographs at this site. Flood profiles were computed for the stream reach by means of a one-dimensional step-backwater model. The model was calibrated using the current stage-discharge relation at the Meramec River near Eureka streamgage and documented high-water marks from the floods of December 30, 2015. The hydraulic model was then used to compute 39 water-surface profiles for flood stages at 1-foot (ft) intervals referenced to the streamgage datum and ranging from 17 ft or near bankfull to 55 ft, which exceeds the stage that corresponds to the maximum recorded peak flow. The simulated water-surface profiles were then combined with a Geographic Information System digital elevation model (derived from light detection and ranging (lidar) data having a 0.5-ft vertical accuracy and 3.28-ft horizontal resolution) to delineate the area flooded at each water level. The availability of these maps, along with Internet information regarding current stage from the USGS streamgage and forecasted high-flow stages from the NWS, will provide emergency management personnel and residents with information that is critical for flood response activities such as evacuations and road closures, as well as for post flood recovery efforts. This dataset was created to support the development of flood inundation maps for a reach of the Meramec River near Eureka, Missouri. A GIS application was used to produce a plane representing the flood-peak water surface by combining the water-surface profiles and digital elevation model data. The digital elevation model (DEM) data were derived from LiDAR data with horizontal resolution of 3.28 ft and vertical accuracy of 0.5 ft at a 95-percent confidence level based on a root mean squared error of 0.28 ft for the open terrain land-cover category. Estimated flood-inundation boundaries for each simulated profile were developed with HEC-GeoRAS software. HEC-GeoRAS is a set of procedures, tools, and utilities for processing geospatial data in ArcGIS by using a graphical user interface. The interface allows the preparation of geometric data for import into HEC-RAS and processes simulation results exported from HEC-RAS. USGS personnel then modified the HEC-GeoRAS results to ensure a hydraulically reasonable transition of the boundary between modeled cross sections relative to the contour data for the land surface. The maps show estimated flood-inundated areas for each of the water-surface profiles that were generated by the hydraulic model.The application duplicates the water-surface-elevation data from cross-section points of the hydraulic model across the flood plain perpendicular to the direction of the flood flow. Elevations between water-surface points on the cross-sections are proportional interpolations of the water-surface-elevation data and were positioned to generate a flood surface sloping with the water flow. A raster surface was created with the data points using a spline interpolation method, forming the estimated flood surface. A flood-depth grid was made by subtracting the DEM from the flood surface raster. For more information on data processing and checking procedures, see the full report at http://pubs.usgs.gov/sir/2017/SIRNUMBER/. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the dataset in nonproprietary form, this metadata file may include some ArcGIS-specific terminology.Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the dataset in nonproprietary form, as well as in ArcGIS format, this metadata file may include some ArcGIS-specific terminology. 2018 publication date Complete None planned -90.657899 -90.553893 38.548408 38.469750 none flood river/stream flood-inundation maps high-water marks flooded area USGS Thesaurus geospatial analysis USGS Metadata Identifier USGS:5bbe7a28e4b0fc368eb3785a Geographic Names Information System (GNIS) Missouri Eureka Valley Park Fenton Arnold Meramec River none none Missouri Water Science Center Director U.S. Geological Survey, Midwest Region mailing and physical

1400 Independence Road

Rolla Missouri 65401 USA 573-308-3667 ambeussi@usgs.gov Attributes for water-surface elevation were input from the HEC-RAS model output data table. Stage input data for the HEC-RAS model were obtained from stage-discharge relation at the USGS streamgage 07019000 Meramec River near Eureka, Missouri. Data published and available at http://pubs.usgs.gov/sir/2018/SIRNUMBER/ There are no unclosed polygons or intersections without nodes. Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. Flood inundation extent was manually checked by sampling the digital elevation model (DEM) adjacent to high water marks. This check was done to verify that DEM elevations greater than the high-water mark were not in the flood inundation polygon and elevations less than the high water mark were within the flood inundation polygon. Flood inundation extent was manually checked by sampling the digital elevation model (DEM) adjacent to high water marks. This check was done to verify that DEM elevations greater than the high-water mark were not in the flood inundation polygon and elevations less than the high water mark were within the flood inundation polygon.Vertical accuracy is limited to the accuracy of the input Lidar DEM dataset. A GIS application (ArcGIS) was used to produce a plane representing the flood-peak water surface by combining the water-surface profiles and digital elevation model data. The digital elevation model (DEM) data were derived from LiDAR data with horizontal resolution of 3.28 ft and vertical accuracy of 0.5 ft at a 95-percent confidence level based on a root mean squared error of 0.28 ft for the open terrain land-cover category. Estimated flood-inundation boundaries for each simulated profile were developed with HEC-GeoRAS software. HEC-GeoRAS is a set of procedures, tools, and utilities for processing geospatial data in ArcGIS by using a graphical user interface. The interface allows the preparation of geometric data for import into HEC-RAS and processes simulation results exported from HEC-RAS. USGS personnel then modified the HEC-GeoRAS results to ensure a hydraulically reasonable transition of the boundary between modeled cross sections relative to the contour data for the land surface. The maps show estimated flood-inundated areas for each of the water-surface profiles that were generated by the hydraulic model.The application duplicates the water-surface-elevation data from cross-section points of the hydraulic model across the flood plain perpendicular to the direction of the flood flow. Elevations between water-surface points on the cross-sections are proportional interpolations of the water-surface-elevation data and were positioned to generate a flood surface sloping with the water flow. A raster surface was created with the data points using a spline interpolation method, forming the estimated flood surface. A flood-depth grid was made by subtracting the DEM from the flood surface raster. For more information on data processing and checking procedures, see the full report at http://pubs.usgs.gov/sir/2018/SIRNUMBER/. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the dataset in nonproprietary form, this metadata file may include some ArcGIS-specific terminology. 2018 Vector Web Mercator 0.0 0.0 0.0 0.0 coordinate pair 1.0 1.0 METERS D_WGS_1984 WGS_1984 6378137.0 298.257223563 Attribute Table Table containing attribute information associated with the data set. Producer defined ELEV NAVD88 water elevation at streamgage, in feet. U.S. Geological Survey 420.84 458.84 feet STAGE USGS stage height associated with the area, in feet. U.S. Geological Survey 17 55 feet GRIDID Grid associated with the area Producer defined 17 55 feet USGSID USGS station ID number U.S. Geological Survey 07019000 USGS station ID number Producer defined GS ScienceBase U.S. Geological Survey mailing and physical

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 USA (303) 202 4220 sciencebase@usgs.gov This database has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and/or contained herein. Although this information product, for the most part, is in the public domain, it also contains copyrighted materials as noted in the text. Permission to reproduce copyrighted items for other than personal use must be secured from the copyright owner. This coverage may be redistributed if it is not edited and is properly referenced. Vector Digital Data Set (Polygon) none http://water.usgs.gov/osw/flood_inundation/ None 20200824 Benjamin J Dietsch U.S. Geological Survey, Midwest Region Hydrologist mailing and physical

5231 South 19th Street

Lincoln Nebraska 68512 USA 402-328-4100 bdietsch@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998