Document Type
Thesis
Abstract
Streams draining the Eastern Virginia Blue Ridge mountains express characteristics associated with underfitness, notably large floodplains compared to their narrow stream beds. Morphometric and GIS analysis was used to study characteristics of 27 drainage basins and climatic conditions affecting them. Analysis indicates a positive relationship between valley size and the percentage of their basin at high elevations (>800m). The mean width of alluvium shows no apparent correlation with drainage basin area, mean annual peak discharge, stream gradient, the gradient difference between upland and piedmont reaches, or the slope of the drainage basin over 800m. The hyposmetric integral does not correlate with drainage basin size. A weak positive correlation exists between the mean width of alluvium and maximum recorded discharge. In contrast, the mean width of the alluvium is positively correlated to the percentage of the drainage basin over 1000 m, over 900 m, over 800 m, and the hypsometric integral. Analysis suggests some streams may be underfit with respect to their current valley size. Existing hydrologic conditions do not seem adequate to form these valleys. During the late Pleistocene, higher elevations within the basins may have extended above timberline and received larger amounts of snowfall. High runoffs during snow melting in the spring may have produced peaks annual discharges 50 to 200% higher than at present. The higher discharge Blue Ridge rivers eroded larger valleys and deposited more sediment than their modern counterparts.
Date Awarded
2009
Department
Geology
Recommended Citation
Wheat, Rhyanne E., "Morphometric Analysis of DrainageBasins in the Blue Ridge province, Virginia: A Case for Underfit Streams" (2009). Geology Senior Theses. William & Mary. Paper 223.
https://scholarworks.wm.edu/geologyseniors/223
