Some 8.8 acres, on average, are cleared to construct a single well pad for a horizontal Marcellus well in Pennsylvania.This includes 3.1 acres for the wellpad itself and 5.7 for the support structures, including access roads.13 Clearing space
for these structures removes thevegetation, which can cause soil erosion. Though other kinds of human activities, such as agriculture and logging, cause the majority of soil erosion in the U.S. and worldwide, regional development of natural gas
resources has the potential to add to this problem. Erosion and sedimentation controls are constructed around access roads at well pads, possibly including berms, ditches, sediment traps, sumps, or fencing.Berms are raised mounds of soil, often constructed in conjunction with a ditch, that help prevent erosion. Sediment traps help catch eroded soil before they enter nearby surface waters, and silt fences are actual fences designed to trap sediment before it washes offsite. These are the flexible black plastic fences commonly seen at construction sites. By one estimate, 8.5 tons of sediment
would be eroded from a 2.57 acre well pad disturbance in New York.The estimates for actual disturbance from well pad construction are more than 3 times that, so if the erosion estimate is correct, more sediment could erode from the average well pad in New York. All of these measures will reduce, but not eliminate, soil erosion. Stormwater Pollution Prevention Plans, required for each well site, would include plans for erosion control.