IMPACTS OF SMALL WATER BODIES ON THE HYDROLOGICAL RESPONSE OF SMALL AGRICULTURAL WATERSHEDS

Author

Nicholas James Longbucco, Southern Illinois University CarbondaleFollow

Date of Award

12-1-2010

Degree Name

Master of Science

Department

Geography and Environmental Resources

First Advisor

Dziegielewski, Ben

Abstract

There are an estimated 2.6 million small water bodies in the contiguous United States. These features are mostly manmade representing a major source of land use change. Compared to larger reservoirs, the impacts of small water bodies on watershed hydrology are not well understood and were the main focus of this research. Using three sets of streamflow parameters, the hydrological impacts of small water bodies were evaluated in 29 watersheds of the Midwest. This relationship was evaluated with four other geophysical watershed traits, and variations in the relationships were examined across three regions of the study area. Of the six geophysical watershed traits examined, results indicate that a watershed's percent area of small water bodies was the strongest predictor of high flow coefficients. This relationship was positive and statistically significant with a distinct regional relationship in Eastern Iowa. Time of concentration and watershed area were significant predictors of low flow coefficients. Time of concentration was also a significant predictor of the rainfall-runoff ratios. The distinct positive relationship between small water bodies and high flow coefficients, and insignificant relationships with runoff ratios are unexpected and intriguing findings, representing possible opportunities for future investigations.