Date of Graduation
Summer 2026
Degree
Master of Science in Geography & Geology
Department
School of Earth, Environment & Sustainability
Committee Chair
Tasnuba Jerin
Abstract
Flood regimes describe how flood behavior changes in magnitude, recurrence, and occurrence through time. Changes in these flood characteristics can affect flood hazards, river systems, infrastructure, and floodplain management. This thesis examines flood-regime change across the Lower Midwest, focusing on Nebraska, Iowa, Kansas, and Missouri from 1961 to 2020. Records from 1,452 U.S. Geological Survey gaging stations were initially compiled, and 208 stations were retained after screening for record availability and analytical consistency. Flood-regime change was evaluated between two 30-year study periods: Period 1 (1961–1990) and Period 2 (1991–2020). The analysis combined Log-Pearson Type III flood-frequency analysis using L-moments in R, recurrence-interval-based flood-magnitude comparison, annual peak-flow recurrence-bin comparison, attribute-based k-means clustering, and GIS-based spatial interpretation Results show that flood-regime change across the Lower Midwest was geographically organized but not uniform. Iowa and Missouri showed widespread positive flood-magnitude changes across most recurrence intervals, while Kansas and Nebraska showed more mixed responses, with positive changes becoming more apparent at larger recurrence intervals. Annual peak-flow occurrence also shifted across recurrence classes. Smaller annual peak-flow classes, especially the Q2–Q5 bin, generally became less common in Kansas, Nebraska, and Iowa, while annual peak flows exceeding the Period 1 Q100 cutoff became more frequent across all four states. Attribute-based k-means clustering identified three flood-response regimes: a Declining Flood Regime, a Moderate Transitional Regime, and an Extreme-Flood Intensification Regime. These regimes showed geographic organization but did not align with state boundaries. Overall, the results provide a regional framework for identifying where flood magnitudes are declining, moderately changing, or shifting toward stronger extreme-flood conditions. These findings may support flood-hazard assessment, infrastructure planning, river management, and adaptive flood-risk planning across the Lower Midwest.
Keywords
Flood regime, flood-frequency analysis, recurrence interval, attribute-based k-means clustering, GIS, Lower Midwest, USGS gaging stations
Subject Categories
Geomorphology | Hydrology
Copyright
© Kaiser Mostafiz
Recommended Citation
Mostafiz, Kaiser, "Flood-Regime Shifts Across the Lower Midwest, USA: Identifying Patterns Through Flood Magnitude–frequency Analysis and Clustering" (2026). Graduate Theses/Dissertations. 4201.
https://bearworks.missouristate.edu/theses/4201
