Lower Missouri River Flood Risk Data

The Missouri River experienced historic flooding in 1993, 2011 and again in 2019. The Lower Missouri River Comprehensive Flood Protection Study is an opportune time for FEMA Region 7 and the USACE Omaha and Kansas City Districts to collaborate in the development of new engineering data to support floodplain management, reduce flood risk, and improve resiliency across multiple States. The Lower Missouri River study area is from Gavin’s Point Dam down to the confluence with the Mississippi river. A total of approximately 811 river miles, 7600 square miles of floodplain, 358 levee systems, 60 bridge crossings, 52 counties, and 5 states are impacted by this study. A key component of this study is the collaboration of subject matter working groups comprised of experts within the USACE, FEMA, and Stantec to develop and validate approaches to accomplish three primary objectives: 1. Successfully establish a framework for multi-federal agency collaboration towards analyzing flood risk from very large river systems that impacts multiple States. 2. Provide a consistent product in a baseline platform ready for future customized enhancements by both agencies to support individual needs. 3. Produce flood risk data in support of FEMA’s Future of Flood Risk Dataset initiative. USACE will provide an updated flow frequency relationships that uses a Monte Carlo analysis. USACE will also bring focus on evaluation of infrastructure performance and its impact on stage frequency. Stantec is producing a detailed 2D HEC-RAS model. The study includes: compilation of LiDAR into a seamless dataset; incorporation of hydrographic survey data of the river channel; compilation of survey data of bridges; leveraging flow frequency data produced by the USACE; performing stream gage analysis; performing rain-on-grid analysis and hydrograph routing of major contributing tributaries; producing 2D HEC-RAS with-levee model; and production of flood risk data.