Date of Graduation

Fall 2016

Degree

Master of Science in Geospatial Sciences

Department

Geography, Geology and Planning

Committee Chair

Toby Dogwiler

Keywords

climate, precipitation, hydrology, flooding, erosion, sediment transport

Subject Categories

Climate

Abstract

As climate change progresses, many forecasts for the upper Midwest predict increases in annual precipitation, but with a shift in seasonal patterns that will leave the summer months drier with less frequent, higher magnitude storm events. Changes in precipitation patterns have the potential to alter the sediment budget and discharge patterns in watersheds. The purpose of this study was to determine the effects changes in frequency, magnitude, duration, and intensity of precipitation might have on streamflow and sediment budgets in the upper Midwest. This analysis was carried out using hourly precipitation data from 1948 to 2013 from 23 sites and 8 river basins in Minnesota, Wisconsin, North Dakota, South Dakota, Nebraska, and Iowa. The hourly precipitation data provide a high-resolution archive that is ideal for analyzing changing patterns in rainfall at multiple scales: including decadal, yearly, monthly, and individual storm event. The upper Midwest is experiencing decreasing storm durations, decreasing numbers of storm events, increasing average rainfall intensities, increasing maximum rainfall intensities, increasing amounts of rainfall per storm, and increasing average annual precipitation. These data demonstrate that significant changes in precipitation and streamflow patterns have occurred over the past 60 years. The observed changes are consistent with the predictions derived from various climate models and, as such, may lend support to forecasts of additional shifts in precipitation patterns in the coming decades. Understanding and quantifying these changes, particularly the trend of shorter more intense storms, has large implications on the sediment budget and discharge patterns of upper Midwest watersheds.

Copyright

© Blake Steven Lea

Available for download on Friday, December 15, 2017

Open Access

Included in

Climate Commons

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