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Archive of hydrologic models used to generate flood peaks based on selected precipitation durations and recurrence intervals for the Little Blue River Basin, Grandview, Missouri

June 11, 2021

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 precipitation events of varying recurrence intervals and durations, and expected changes in land cover. 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 54 precipitation events. The Hydrologic Engineering Center-River Analysis System (HEC-RAS) version 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 interval) at the USGS streamgage Little Blue River at Grandview, Missouri (06893750). The calibrated HEC-HMS model was used to simulate streamflows from design precipitation 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 zip file (LittleBlueRiver_Grandview_HEC-HMS_model_archive.zip) containing all relevant files to document and run the Hydrological Engineering Center-Hydrologic Modeling System (HEC-HMS) one dimensional hydraulic model used to generate flood peaks for input in hydraulic model.