Assessment of the hydrological impacts of human alteration of Maryland Piedmont streams

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Date

2020-07-02

Department

Towson University. Department of Geography and Environmental Planning

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Abstract

The hydrologic regime plays a vital role in aquatic ecosystems. However, these systems are altered by land use change and anthropogenic climate change. Urbanization increases surface runoff and decreases infiltration, while climate change affects precipitation. This study assesses the degree of hydrological impacts to the Maryland Piedmont using stream gauge data from twenty urban to rural sites from 1980 – 2014. Eight sites show significant increasing trends using the Mann-Kendall test, although all but one sites show increases. At the same time, base flow appears to be steady for all sites or decreasing over time. Piedmont streams share many characteristics regardless of size or landcover. August is typically the driest month, while March is the wettest; Winter months tend to have the least variation in discharge, while Summer tends to have the most. All sites responded in the same way to annual climate variations; for example, 2002 was one of the driest years for all sites, followed by one of the wettest years in 2003. Although all sites experienced the same wet years, it appears that rural and urban sites experienced drought in different ways, with urban watersheds having the worst drought in 1998, while 2002 was the driest on record for rural sites. Land cover had other effects as well. In general, urbanized streams have more flashy peaks in their hydrographs, and have a wider range of discharges but a lower median discharge than their rural counterparts. This research will be valuable to assess mitigation strategies in order to protect the ecosystem, infrastructure, and livelihood in the watershed where urban development is inevitable.