Landscape Effects of Oil and Gas Development

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Relatively new deep well drilling technology, such as is currently utilized in hydraulic fracturing (“fracking”), has created an economic boom in the market for hydrocarbons. Previously untapped deposits of oil and natural gas can now be accessed in areas that include the Marcellus and Utica Shale deposits in the east and the Bakken Formation in Montana and the Dakotas.

While there are many environmental concerns associated with fracking, one of the often overlooked issues is the effect that these practices have on the landscape. Ecosystems and the services that they provide are largely affected by the spatial arrangement of energy development on the landscape. Fracking, and hydrocarbon development in general, results in surface disturbance from drill pads, roads and pipelines that alter landscape dynamics and habitat characteristics such as forest edge and forest interior area. Figure 1 shows an example of a forested area in Pennsylvania with high oil and gas development activity.

Satellite image of a forested landscape showing the disturbance pattern from mostly conventional hydrocarbon development

Figure 1. A forested landscape in McKean County Pennsylvania showing the disturbance pattern from mostly conventional hydrocarbon development (from Slonecker and Milheim, 2015).

(Public domain.)

To study this effect, scientists funded by the USGS Climate Research & Development Program extracted features of landscape disturbance related to hydrocarbon development from high-resolution aerial photographs in the Marcellus Shale region of Pennsylvania for the period of 2004 – 2010. Using geographic information system (GIS) technology and ancillary data from state databases, disturbance features were mapped and statistically summarized.

Results show that the disturbance from the newer hydraulic fracturing activity, termed “Unconventional Oil and Gas,” is only part of the landscape change story in Pennsylvania. Conventional oil and gas wells, which are also prevalent and have a long history in Pennsylvania, receive far less scientific attention and account for more landscape disturbance that their unconventional counterpart (Figure 2). Other important results from this research effort include the discovery that some form of landscape disturbance related to conventional or unconventional oil and gas development occurred in approximately 50% of the 930 watersheds studied. This development was closer to streams than the state-defined recommended safe distance of 100 feet in approximately 50% of the watersheds. Landscape disturbance was in some places closer to impaired streams and wildland trout streams than the recommended safe distance and occurred in approximately 10% of exceptional value watersheds. Disturbance tended to occur at interior forest locations, which are critical for some plant and animal species, and occurred in approximately 30% of the watersheds with resident populations defined as disproportionately exposed to pollutants.

Maps illustrating the locations of conventional and unconventional oil and gas development sites.

Figure 2. Location of conventional (A) and unconventional (B) oil and gas developments sites. Site are displayed as points (modified from Slonecker and Milheim, 2015).

(Public domain.)

The paper, Landscape Disturbance from Unconventional and Conventional Oil and Gas Development in the Marcellus Shale Region of Pennsylvania, USA, was published in Environments in 2015.