Semester

Fall

Date of Graduation

2007

Document Type

Dissertation

Degree Type

PhD

College

Davis College of Agriculture, Natural Resources and Design

Department

Wildlife and Fisheries Resources

Committee Chair

J. Todd Petty.

Abstract

Acid mine drainage (AMD) and acid rain are important sources of impairment to streams in the Tygart Valley and Cheat River basins in north central West Virginia, USA. Due to a network of abandoned mined lands and bond forfeiture sites in this coal-mining region, AMD represents severe, but rather localized impacts to water quality. AMD is a consequence of the chemical oxidation of reduced geological minerals (sulfides) usually associated with coal during mining operations. The reactions produce aqueous solutions high in sulfates and dissolved metals when the minerals are exposed to the oxic environment through land disturbance. In addition, the weakly buffered and mostly acid producing to circum-neutral mineral geology of this region makes surface waters susceptible to the chemical consequences of acid rain. Acid rain forms when gaseous compounds of nitrogen and sulfur from fossil fuel combustion react with atmospheric moisture.;I tested a classification system based on water chemistry in streams of these two basins. Streams of the region ranged from very good water quality (reference type) to increasingly impaired by AMD (moderate to severe AMD types). Streams with soft water had characteristics associated with the impacts from acid rain, and streams with hard water were either natural occurrences or were influenced by alkaline materials injected into water to treat acid sources. A transitional water quality type was recognized, which was very difficult to characterize because of its gradation in chemistry across the spectrum from reference and hard water types to waters increasingly influenced by AMD.;It is commonly observed that benthic macroinvertebrates in streams from unpolluted waters are distributed continuously without being organized into discrete communities. The discreteness of water quality observed in this research, however, suggests that benthic macroinvertebrates ought not to be distributed continuously, but rather should correspond discretely to water quality types as distinct communities. Therefore, I tested the expectation that macroinvertebrate communities should be distributed in concordance with water quality types in the Cheat River basin. Multivariate models suggested that water quality types significantly structured macroinvertebrates. Measures of classification strength by water quality on community composition were weak, but significant. Indicator species analysis found several important macroinvertebrate genera that were linked especially to reference and soft water quality types.;In the Cheat River mainstem, benthic macroinvertebrate communities and a measure of stream ecosystem health were highly correlated to spatial and temporal inputs of AMD and thermal effluent. However, when these stressors occurred simultaneously, stream health and community structure did not recover with downstream improvements in water quality as they did when stressors occurred singly. In the Cheat River mainstem overall, AMD was responsible for most degradation, but AMD in combination with thermal effluent was also responsible for extensive loss of ecological integrity in the Cheat Canyon region. Consequently, local water chemistry accounts for the distributions of benthic macroinvertebrates in the Cheat basin. Therefore, macroinvertebrates may respond in predictable ways to restoration efforts that reduce harmful chemical constituents associated with acidic impacts. Large, watershed-scale attributes may be needed to explain variation in benthic macroinvertebrate communities not captured by local water quality types.

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