Authors: Jonathan Remo*, Southern Illinois University, Carbondale
Topics: Water Resources and Hydrology, Geomorphology, Hazards, Risks, and Disasters
Keywords: Floods, Mississippi River,
Session Type: Paper
Start / End Time: 9:55 AM / 11:35 AM
Room: Buchanan, Marriott, Mezzanine Level
Presentation File: No File Uploaded
Recent paleo- and historic- flood research along the lower Mississippi River (LMR) has expanded its flood record to more than 500 years. However, hydraulic impacts of river engineering during the late-19th through the mid-20th centuries have resulted in substantial nonstationarity in this record. Due largely to this nonstationarity, flood frequency analysis has not been attempted for the LMR. In this study, we attempt to overcome the nonstationarity in the LMR flood record by developing a calibrated and validated 1-D unsteady flow retro-model to create a substantially less-engineered reference condition (i.e., little to no channel engineering and no levees). The retro model is constructed using historical hydrologic and geospatial data from the mid- to late- 19th century. Routing discharge inflows through the retro- model provides an estimate of flood magnitude for a common reference condition. Comparing the difference between the referenced and observed peak flood discharges provide an estimate of change in flood magnitudes. The estimated change in peak flood magnitudes is used to reference paleo and historic flood discharge measurements to current river conditions. The contemporary referenced paleo and historic discharges are used as threshold bounds in the Bulletin 17c flow frequency analysis to provide a more robust estimate of flood frequency utilizing the full LMR’s 500-year flood record.