Hydrologic Response and Erosion Modeling of Geomorphic Landform Reclamation in Mountainous Terrain

Abstract

Surface mining and valley-fill practices often lead to environmental impacts including headwater stream loss, increased flooding risk, and degraded downstream water quality. Geomorphic landform design (GLD) is an innovative reclamation technique proposed to lessen the impacts associated with surface mining and valley-fill activities. GLD incorporates mature landform shapes and created stream channels on site, imitating the function of the undisturbed landscape. The purpose of this research was to model GLDs in mountainous terrain and evaluate the hydrologic response and erosion potential of GLD in surface mining application. Computer modeling of valley-fill designs using geomorphic landform principles of a study site in southern West Virginia was performed. Four enhanced GLDs were created for application on new and previously constructed valley fills: 1) regional data GLD for new valley fill, 2) retrofit GLD for existing conventional valley fill, 3) regional data GLD enhanced with bench pond retention structures, and 4) regional data GLD enhanced with valley pond retention structures. Soil erosion was evaluated using the Revised Universal Soil Loss Equation (RUSLE) for the regional data GLD, conventional valley fill, and the undisturbed site during different stages of the reclamation process. Soil loss rates were highest (conventional: 123.2 t ha-1 yr-1 ; GLD: 204.3 t ha-1 yr-1) during the post-mining, pre-vegetation condition along the stream channels and steep slopes (slope >50%). Erosion rates were lowest for the post-reclamation, long term condition (conventional: 35.6 t ha-1 yr-1 ; GLD: 41.8 t ha-1 yr-1) along the ridges. Model predictions of soil erosion rates and spatial distributions illustrated areas of increased erosion potential for future minimization and reclamation method/management practices improvement. Hydrologic response modeling was performed for a watershed in southern West Virginia disturbed by surface mining and valley-fill activities to predict impacts on stream flows at the landscape scale. Incorporation of GLD reclamation methods did not result in substantial changes in current (2011-2020) or future (2041-2050) stream flowrates (<3.3% difference) or stormflow volumes (<2.1% difference). The differences in flows and volumes could be used for mitigation plans in watersheds disturbed by surface mining and valley-fill activities. iii Dedication To Cooper Allen Sears, our lil' man You are kind. You are smart. You are important. Your family loves you more than everything. The author would like to thank all of the people who committed their time and effort to the success of this research and her success in return. Special thanks go to the people that provided particular support and guidance including Dr. Leslie Hopkinson and Dr. John Quaranta for serving as my co-advisors, Dr. Vladislav Kecojevic, Dr. Hema Siriwardane, and Dr. Brijes Mishra for serving as a committee member. Without the knowledge and supervision of these individuals, this research would not have been successful. In addition to h...

Estimating Ecological Responses to Climatic Variability on Reclaimed and Unmined Lands Using Enhanced Vegetation Index

“…For example, not always are there such huge topographic differences between reclaimed and original landforms like the Pingshuo mining area, which means that surface mining did not necessarily lead to big changes in on-site wind speed and solar irradiation. Especially when geomorphic reclamation is applied, which mimics the geomorphic function of the natural landscape [60,61,91], the topography is similar with that of the natural landscape.…”

“…Third, apart from the topsoil, other vadose zone structures (i.e., subsoil, bedrock lithology) and aquifers overlying mineral deposits are also disturbed and permanently changed, which alters subsurface hydrological processes [52][53][54][55], and influences plant water availability [56,57]. Fourth, surface mining activities permanently change the original topography, further altering microclimatic [58,59] and hydrological processes [53,60,61]. All four aspects of biotic and abiotic changes arising from surface mining may make reclaimed ecosystems respond differently to regional climatic variability from their adjacent remnant analogues.…”