Topographic and Soil Constraints to Shale-Gas Development in the Northcentral Appalachians

Worldwide, shale-gas development is becoming a feasible extraction practice and the northern Allegheny Plateau, USA is a region experiencing such development. We used a GIS to investigate topographic and soil characteristics across existing and permitted shale-gas pads in Pennsylvania, which could affect infrastructure development and reclamation success. Results from this analysis, while regionally specific, can contribute knowledge for successful management of all shale-gas extraction. Approximately 60% of existing and permitted pads occur on slopes at risk to some excess surface water movement and local erosion. Pad development occurs >90% of the time on back-slope landscape positions and 37% of the time on soils with a fragipan subsoil horizon, which can contribute to soil drainage problems. Most pads (73%) are developed on soils without drainage problems, but 21% are on potentially wet soils. Shale-gas development related to one pad typically disturbed a 0.1- to 20.5-ha area (mean of 2.7 ha). Aerial photography analysis from 2010 indicates a small proportion of pads have undergone restoration, and restored pads were recontoured and planted with grass. Agricultural lands restored after infrastructure development were found to return to some crop production. Assuming perfect site reclamation, grass, herbaceous, hardwood, and conifer establishment appears suitable across the range of existing and permitted pads; however revegetation success may be limited by poor soil reclamation.