Geospatial data and hydraulic-model archive for evaluation of flood-inundation maps developed for a reach of the Little Blue River at Grandview, Missouri

The U.S. Geological Survey (USGS) in cooperation with the city of Grandview, Missouri, assessed flooding of the Little Blue River at Grandview resulting from varying precipitation magnitudes and durations, and expected land cover changes. The precipitation scenarios were used to develop a library of flood-inundation maps that included a 3.5-mile reach of the Little Blue River and tributaries within and adjacent to the city. A hydrologic model of the upper Little Blue River Basin, and hydraulic model of a selected study reach of the Little Blue River and tributaries were constructed to assess streamflow magnitudes associated with simulated precipitation amounts and the resulting flood-inundation conditions. The U.S. Army Corps of Engineers Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) version 4.41 was used to simulate the amount of streamflow produced from a range of rain events. The Hydrologic Engineering Center-River Analysis System (HEC-RAS) ver�sion 5.07 was then used to construct a steady-state hydraulic model to map resulting areas of flood inundation. The hydraulic and hydrologic models were calibrated to the May 28, 2020, high-flow event that produced a peak streamflow approximating a 10-percent annual exceedance probability (10-year flood-frequency recurrence intervals) at the USGS streamgage Little Blue River at Grandview, Missouri (06893750). The calibrated HEC-HMS model was used to simulate streamflows from design rainfall events of 1- to 8-hour duration and ranging from a 100-percent to 0.2-percent annual exceedance probability. Flood-inundation maps were produced for USGS streamflow stages of 17 feet or near bankfull up to 23 feet or the stage exceeding the 0.2-percent annual exceedance interval flood using the HEC-RAS model. This data release includes: 1) a raster dataset of the streamflow depths at reference gage stages of 17.0 to 23.0 feet (LittleBlueRiverStreamflowDepths.zip); 2) a polygon dataset of the streamflow inundation extent (LittleBlueRiverStreamflowExtents.zip); 3) a zip file containing all relevant files to document and run the Hydrological Engineering Center-River Analysis System (HEC-RAS) one-dimensional hydraulic model used to generate raster datasets of stream depth and polygon datasets of streamflow extent (LittleBlueRiver_HEC-RAS_ModelArchive.zip).