Publication Date


Document Type


First Advisor

Changnon, David

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Geography


Geography; Watersheds--Research--Middle West; Urban watersheds--Research--Middle West; Rain and rainfall--Research--Middle West; Urbanization--Research--Middle West


Wide spread urban development and its associated conversion of natural and agricultural lands to land use types dominated by impervious surfaces such as motorways, car parks, and structures has had and continues to have significant impacts on drainage basin hydrology and fluvial ecosystems. As a drainage basin becomes increasingly developed, the ratio of basin discharge in response to rainfall events increases, leading to a greater frequency and intensity of flood events. The purpose of this study was to develop a population density-based model to forecast discharge-precipitation ratios for drainage basins undergoing changes in degree of urbanization. This model, with its use of population density as an indicator for level of urbanization, relates the impacts of human-induced landscape modification on surface hydrology from a planning perspective and in a context that is aimed to resonate with a broader audience. This study examined this relationship for 18 Midwestern drainage basins. The discharge-precipitation ratios of warm-season large rainstorm events of drainage basins for the time period between 1948 and 2014 were related to the population densities of the respective basins at the time of the event. Rainfall events greater than or equal to 5.1 cm occurring within a 48-hour period over the basin from April 1st through October 31 st were defined as warm-season large rainstorms. As expected, the study indicated no significant changes in the discharge- precipitation ratios for rural drainage basins, however there were significant increases in the ratio of discharge to precipitation for the six urban drainage basins. A non-linear, positive relationship was found between discharge-precipitation ratios of large rainfall events and population density in the urban basins. This resulting model demonstrates to what degree planners may expect variations in the level of development to impact drainage basin hydrology and provide them with information to consider while implementing drainage system designs, flood management policies, green infrastructure, and building code.


Advisors: David Changnon.||Committee members: Xuwei Chen; Richard Greene; Wei Luo.


136 pages




Northern Illinois University

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