Document Type

Thesis

Abstract

Stream capture is not regularly considered as a driver of landscape evolution on the Coastal Plain of Virginia. Here, gently sloping meandering rivers gradually work sediment, and carve the landscape producing gradual topographic adjustment. However, one river in particular stands out from the rest. The Chickahominy River, a tributary of the larger James River, appears to have been altered, changing its original drainage basin. The curious nature of the Chickahominy River and neighboring South Anna River lead me to hypothesize that a stream capture event has occurred between the two rivers. Unlike many rivers on the Coastal Plain, the Chickahominy barely drains the eastern Piedmont. On the contrary, the South Anna, lying 7 km to the northwest, continues nearly into the Blue Ridge. When compared to six other rivers within eastern Virginia, the Chickahominy River displays a significant difference. The Chickahominy River is much shorter in total channel length, with a measured 35% difference from averaged channel lengths. Unlike the six other rivers, the Chickahominy also contains a much smaller portion of its drainage area (15%) above the Fall Zone versus below it. This difference in drainage area above and below the Fall Zone becomes even more evident when compared to the six other rivers, which contain 95%, 98%, 41%, 85%, 39%, and 42% of their drainage area above the Fall Zone. When changes within the Chickahominy River basin across the Fall Zone are investigated further, it is shown that the Chickahominy River’s valley becomes ~7 times wider once crossing this boundary. This study explores the possibility of stream capture by comparing seven major rivers, to understand why the Chickahominy River is drastically different when compared to it’s neighboring counterparts.

Date Awarded

2016

Department

Geology

Advisor 1

Christopher M. Bailey

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