Date of Award

2018

Document Type

Open Access Thesis

Department

Earth and Ocean Sciences

Sub-Department

College of Arts and Sciences

First Advisor

Allan James

Abstract

The effects of urbanization and associated land use changes, specifically increases in impervious surfaces, have long been the focal point of urban hydrologic research. However, studies and calculations that consider impervious surfaces alone do not encompass all factors that influence urban hydrologic response. Artificial structures such as storm sewer (SS) systems and road networks increase rates of stormwater conveyance, yet these artificial networks are rarely considered in computations of drainage densities and associated hydrologic alterations. This study examines several hydrologically relevant descriptors that can be used to better understand the impact of urbanization on small watersheds. Rainfall and stormflow data were analyzed to compare the hydrologic response of two subcatchments in a highly urbanized watershed, Rocky Branch Watershed (RBW). Subcatchments with varying characteristics of percent impervious areas (PIA) and drainage densities were analyzed in order to determine the effect of PIA, storm sewer systems (SS), and the urban drainage system (UDS) as a whole, including road-side gutters and ditches. The results from this study show that the subcatchment (Gervais) with a higher PIA produced higher runoff volumes, while the other subcatchment (MLK) with higher SS and UDS densities displayed shorter lag times following storm events. In this case, PIA increased the volume of runoff, but the SS and UDS densities accelerated the hydrologic response by conveying water at faster rates. The results from this study indicate that alternative hydrologically relevant metrics, such as SS and UDS densities should be considered in urban stormwater management in order to minimize flood risk.

Rights

© 2018, Logan Ress

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