ASSESSING LANDSCAPE DISTURBANCE AND THE ECOLOGICAL SITUATION OF ENERGY DEVELOPMENT IN THE U.S. AND RUSSIA
Energy development landscape studies often centre on better understanding how oil and gas extraction creates alterations on the land that contribute to habitat fragmentation,
colonisation and loss of natural areas. Today, however, energy sources are drawing on renewables such as solar and wind, because they are viewed as cleaner, don’t emit CO2
, they
receive incentives, and are being increasingly required as part of a balanced energy mix in many US states.
Meanwhile, these alternative supplies are seen as creating less adverse environmental effects than oil and gas. Yet they too create a disturbance footprint on the landscape that can lead to permanent loss of habitat, thus affecting carbon stores, ecosystem goods and services and biodiversity. This issue is particularly salient in sensitive areas, such as steppes with unique and diminishing grasslands. Additionally, wind turbines often lead to bird and bat mortalities. Our current research on energy production aims to develop diagnostic indicators for mapping and measuring surface
disturbance related to energy development, both hydrocarbon and renewable wind power. As part of our NSF-CRDF grant, American and Russian teams are studying energy landscapes in northeastern Colorado and western Russia. Using remote sensing and GIS data and techniques we examine the Pawnee National Grasslands in Weld County, Colorado and the oil and gas fi elds in and around Buzuluk National Forest in Russia’s Orenburg state. Our objective is to better understand the pattern and extent of the energy development footprint in order to develop disturbance indicators to enhance environmental performance standards in the energy industry (both hydrocarbon and renewable). Initial results are reported below.
Study Area: Colorado
Colorado is 6th largest oil and gas producer in the US, with Weld County having the highest well density in the state. Located in northeastern Colorado, this state is also home of the Pawnee National Grasslands, a unique and diminishing mosaic of natural prairie grasslands that is interspersed with federal, state and private land and where the dominant economic activities are oil and gas extraction, wind production, agriculture and grazing. We selected the eastern Pawnee because it contained both oil and gas and wind production in order to allow a comparison of landscape disturbance associated with each type (see Figure 1).
We began by creating 1km² grids of the study area and systematically examined oil and gas wells provided the Colorado Oil and Gas Commission (COGCC 2015). From each grid we extracted producing wells, which numbered 561, a density of 0.0027 wells per hectare—see fi gure 2. Then using fi eld data and air photos of eastern Pawnee (NAIP 2015) we visually examined all wells to determine if they indeed were located on a wellpad (a cleared fl at area where wells and supporting equipment are established), and digitised the disturbance footprint of each one. This resulted in 444 wellpads of varying sizes, ranging from small remote ones (0.0087 ha) to very large fracking pads (37.60 ha) located along primary roads. In addition, all access roads leading to wellpads were digitised and buffered by road width—see fi gure 3.
Finally, we calculated the overall disturbance created by the wellpads and the buffered access roads, resulting in 1,267.09 hectares. This translates into an average disturbance of 2.85 ha per wellpad, or 2.26 ha per oil or gas well.
Next, we examined the imagery for the location of the Cedar Creek I and II wind project located in the northern part of the study area (Pacifi c Power 2015). We digitised the center location of 397 wind turbine pads, then randomly examined the size of 20 pads to calculate an average turbine pad size of 0.6 hectares. Since most turbine pads were of uniform size, we assigned this fi gure to all pads, creating a buffered polygon which we smoothed with 20º Bélzier curves (using ArcMap 10.3.1). We further shifted and rotated each polygon to overlay on the centre of each turbine to better resemble the disturbance on the landscape.
Additionally, we digitised the lengthy access roads (169.50 km) linking the turbines together, as well as the transmission lines
Figure 1: Pawnee National Grasslands study area, located in Weld County, Colorado.
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