Date of Award

12-2010

Degree Type

Thesis

Degree Name

Master of Science

Major

Environmental Engineering

Major Professor

John S. Schwartz

Committee Members

Amy M. Johnson, Qiang He

Abstract

Atmospheric acidic deposition has negatively impacted many Appalachian watersheds in the eastern United States and soils play a key role in the biogeochemical processes that govern the fate and transport of the acidic pollutants. Thus, the collection of soil chemistry data, a previously lacking component, is essential to understand the soil processes related to the retention or release of basic and acidic ions and is imperative for the prediction of ecosystem recovery. Soil chemical properties related to acidification were characterized for 25 sites within eight acid-sensitive watersheds located in the Great Smoky Mountains National Park (GRSM). Relationships were identified by comparing soil chemistry to watershed characteristics including site location, soil characteristics, forest type, geomorphic factors and the presence of Anakeesta. The Walker Camp Prong watershed had significantly higher soil base saturation, calcium and magnesium than all other study watersheds as a result of the application of dolomitic limestone to roadways for wintertime traction control. Significant differences in soil chemistry between the spatially close watersheds of Cosby and Rock Creek demonstrated how local factors can substantially influence the watershed acidification response. The chemical properties of the six study soil types, representing 60% of the entire GRSM, had no significant differences, suggesting soil chemistry must be governed by external inputs and basin characteristics, more so than parent material. This idea was strengthen by the ability to relate many soil chemical properties to forest type and identifying other chemical properties as functions of elevation, slope and soil depth. Also, the presence of unexposed Anakeesta did not seem to have any significant effect on soil chemical properties because all significant differences could be linked to factors unrelated to surficial geology. The majority of the soils of the GRSM study watersheds seem to be experiencing the deleterious effects of long-term exposure to acidic deposition and it could be assumed that soils in many other areas of the park may be enduring the same. The results provide a comparative baseline dataset and important input parameters for biogeochemical modeling. The relationships identified among watershed factors and soil chemical properties can aid in future study designs.

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