When developing oil and gas well pads, vegetation and soil are removed to level areas for drilling and operations. The recovery of well pads following oil and gas development is an area of growing importance because recent technological advances such as hydraulic fracturing and horizontal drilling have initiated rapid increases in oil and gas development and production. Active management intervention, or rehabilitation, of vegetation and soils at abandoned well pads has become more common in recent years, but additional research could increase the success of these efforts. We developed a new disturbance automated reference toolset (DART) to assess human land surface impacts using soil-type and ecological context. DART identifies reference areas with similar soils, topography, and geology; and, based on a satellite vegetation index, compares the disturbance condition to the reference area condition using a quantile-based approach. We used DART to examine recovery at 1,858 inactive well pads on the Colorado Plateau, a dryland region in the southwestern US. The goal of this regional assessment is to help resource managers make informed decisions for future well pad development.
Results/Conclusions
DART was able to represent 26-55% of variation of relative differences in bare ground and 26-41% of variation in total foliar cover when comparing sites with nearby ecological reference areas using the Soil Adjusted Total Vegetation Index (SATVI). Assessment of ecological recovery at oil and gas pads on the Colorado Plateau revealed that most abandoned oil and gas pads in the study are characterized by more bare ground and less vegetation than comparable undisturbed areas, even though more than 9 years have passed since abandonment (range of 9 to 17 years). The majority of pads had 15-45 percent increases in bare ground exposure relative to comparable nearby areas. Well pads in grasslands, blackbrush (Coleogyne ramosissima) shrublands, arid canyon complexes, warmer areas with more summer-dominated precipitation, and state administered areas are not recovering as well as other ecotypes or locations. Differing recovery indices across environmental gradients and land stewardship types suggest that these can be useful for identifying conditions that may promote or hamper pad recovery. It is still unclear exactly how long well pad disturbances persist on the landscape once well pads are abandoned, particularly in more arid regions like the Southwest, but it may take many years. New technological advances like DART can help land managers better understand these disturbances by providing timely assessments to help inform management decisions.