Geomorphic Differences Between Unmined and Surface Mined Lands in Southeastern Ohio
A Graduate Defense Seminar will be presented by Matthew Pollock, MS Candidate in Ecological Restoration, on Friday, April 10th at 10:00 a.m. in 460 Kottman Hall and 123 Williams Hall. Matt will present Geomorphic Differences Between Unmined and Surface Mined Lands in Southeastern Ohio.
Surface mining for coal is a significant landscape disturbance that occurs throughout the United States, extending from the Appalachian Mountain Region in the eastern part of the country westward to Wyoming, Arizona, Texas and small portions along the West Coast. Surface mining and reclamation activities result in sometimes dramatic physical reconfigurations of hillslope and stream channel networks, which in turn alter hydrologic and geomorphic processes across the terrestrial and fluvial regions of the landscape. To date, surface mining related research has focused on hydrological impacts with little attention to morphologic alteration. This study quantifies terrestrial and channel geomorphic differences between mined sites reclaimed according to the 1977 Surface Mine Control and Reclamation Act (SMCRA), sites mined prior to SMCRA and unmined sites. The research approach includes analysis of two watershed treatment types, pre-SMCRA mined (reclaimed) and post-SMCRA mined (unreclaimed), as well as unmined watersheds at three spatial scales, which include the terrestrial landscape (100 km2), network topology (103m), and channel reach (101 m) scales. Seven watersheds within each of the three types (pre-SMCRA, post-SMCRA and unmined, n=21; ~1km2 each) were evaluated at the three scales using Geographic Information Systems (GIS) and field methods. Study sites were located on and adjacent to lands managed by American Electric Power (AEP) in southeastern Ohio, USA. A combination of univariate methods (Kruskal Wallis or KW non-parametric tests) and multivariate methods (Nonmetric Multi-Dimensional Scaling or NMDS, Permutational Multivariate Analysis of Variance or PerMANOVA and standardized linear models) were used for analyses. At the landscape scale, Post-SMCRA sites were significantly different from Pre-SMCRA and unmined sites, with reduced mean terrestrial slope (KW p=0.001), increased mean hillslope length (KW p=0.003) and reduced profile roughness (KW p=0.001). At the network topology scale, the amount of wetland coverage was found to be greater for all mined sites, relative to unmined sites (KW p=0.001) with correspondingly reduced distances between outlet reaches and the nearest upstream wetland area (KW p=0.038). At the outlet reach scale, unmined sites were more sinuous than Pre-SMCRA and Post-SMCRA sites (KW p=0.049) while Pre-SMCRA sites had significantly lower width/depth ratios than Post-SMCRA sites (KW p=0.039). Multivariate analyses largely support the hypothesized influential effects of mining and reclamation across all spatial scales, directly and indirectly. The reclamation of surface mined lands is a somewhat unique prospect in that the soils, topography, drainage networks and vegetation can be directly manipulated in order to achieve the greatest possible capacity for future use. Findings from this study provide surface mine reclamation practitioners with new information regarding topologic and geomorphic processes in reclaimed areas in order to continue the optimization of reclamation strategies. In particular, reclamation strategies must incorporate greater topographic and topologic complexity in order to more closely resemble unmined conditions.