Date of Graduation

Summer 2014

Degree

Master of Science in Geospatial Sciences

Department

Geography, Geology, and Planning

Committee Chair

Robert Pavlowsky

Abstract

Climate change influence on the hydrology and ecology of Midwestern Rivers is poorly understood. Flood frequency analysis is used to interpret the historical variability and recent trends in flood magnitudes in Ozark Highland Rivers at twelve USGS discharge gage stations with over 90 years of record, ranging in drainage area from 1,000 to 10,000 km2. Flood frequency distributions for the annual maximum series were calculated over rolling 30 year periods at 5 year intervals from 1922 to 2012 to examine temporal trends of flood magnitudes ranging from the 1.5- to 100-year recurrence intervals. Discharges of the 2-year flood have increased by an average of 30% over the past 30 years at eleven of the gages. Eight of the gages have 25-year flood discharges that are currently greater than the long-term 50-year flood magnitude. The 100-year flood discharge has increased by an average of 39% at eleven gages. Urban area percentage may play a role in the observed increases in high frequency floods, but has little to no effect on moderate/low frequency floods changes. A climate-related latitudinal control on high frequency flood discharges may occur, though more study is needed. USGS regression equations under predict 100-year flood discharges for ten of the twelve studied gage stations. Recent increases in flood discharges in the Ozarks are likely linked to increased precipitation extremes observed across the Midwest as a result of anthropogenic climate change.

Keywords

Ozarks, flood, climate, rivers, change, time

Subject Categories

Climate | Hydrology | Water Resource Management

Copyright

© Andrew Thomas Foreman

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