Degree Year

2014

Document Type

Thesis

Degree Name

Bachelor of Arts

Department

Geology

Committee Member(s)

Amanda Schmidt, Chair
Karla Parsons-Hubbard
Carlo Demarchi

Keywords

Yunnan, China, Weixi, Basin, Sediment, Rainfall, Erosion

Abstract

This paper looks at the dynamic interphase connecting post-revolutionary politics, modern land use practices, precipitation patterns, basin slope, and sediment yield records in Weixi basin, a small mountainous watershed in Southwestern China with a total upstream area of 198 m2. The goal is to identify what processes, climatic or not, account for the changes in local sediment yield and erosion budget. Weixi basin has an average annual sediment yield of 175 ton/km2 with two anomalously large peaks in 1979 and 1984. Precipitation is moderately correlated with sediment yield at interannual scale. It also affects seasonal fluctuations in sediment yield as major sediment loading events correspond to spring snowmelt and monsoon rainfall. However, there is no long-term trend in precipitation that could explain the peak in sediment yield. Land use/land cover classification shows an average of 22.8% bare land in Weixi basin, but no definitive conclusion about temporal changes could be drawn yet due to the discrepancy in imagery resolution. Short-lived radionuclide analyses show there is no correlation between upstream land use and depth of erosion, whereas slope is a moderate control for erosion depth.

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