Semester

Fall

Date of Graduation

2007

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Wood Science and Technology

Committee Chair

Jingxin Wang.

Abstract

The amount of sediment delivered to stream channels and the determination of the topographical attributes responsible for the origination and transfer of sediment were investigated in a central Appalachian mixed hardwood forest from 2002 through 2005. Two study watersheds were chosen within the Indian Run watershed in north central West Virginia. One remained undisturbed (control) and the other underwent road construction and tree harvesting operations (treatment). Sediment samples were collected from silt fences which were installed along both sides of the stream channels in both watersheds to ensure all sediment material delivered from adjacent hill-slopes was captured and collected. Sediment samples were collected annually, and analyses were performed on pre-road/harvest and post-road/harvest samples for the treatment watershed. The same sample collection and analysis procedures were performed for the control watershed as well. Visual, physical, and spatial observations were made before, during, and after road construction within the treatment watershed. Data were analyzed both spatially and statistically to determine the magnitude of effects from the topographical attributes, the road construction, and the harvesting operations on sediment delivery to the stream channel. The spatial and statistical analyses indicated an increase in sediment material production as a result of road construction within the treatment watershed as the annual sediment material collected increased some 1.7 times the year after the road construction procedure. On average the treatment watershed produced 7.2 times as much sediment material per-acre as did the control watershed over the study period. The variables in the treatment watershed that explained a significant (alpha=0.10) amount of sediment delivery were year, distance to tree falls (rootwads), distance to water driven erosion features (WDEFs), distance to naturally bare soil, and the distance to animal trails. Significant variables for the control watershed were year, contributing slope from each topographical feature, distance to naturally bare soil, bare soil area, and the distance to animal trails. Additionally, soil loss equations, specifically the Revised Universal Soil Loss Equation (RUSLE), were tested to compare modeled results to field measured results under these mountainous conditions. The soil loss equations had poor accuracy, yielding predictions many times larger than the actual masses of collected data.

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