Southwest Energy Development and Drought (SWEDD)

Science Center Objects

Deserts of the southwestern US are replete with oil and gas deposits as well as sites for solar, wind, and geothermal energy production. In the past, many of these resources have been too expensive to develop, but increased demand and new technologies have led to an increase in exploration and development. However, desert ecosystems generally have low resilience to disturbance. More frequent, intense droughts forecast for the southwestern US will likely further hamper recovery of disturbed lands. Consequently, there is a need for new science to anticipate and mitigate the effects of energy exploration and development. The Colorado Plateau Region contains approximately 100,000 abandoned and current wells spanning 60 years of activity. These structures are spread over a variety of substrates, climate zones, elevations, and vegetation communities, with varying periods of use and time since abandonment. The overarching goal of this project is to understand how past and current energy development are impacting the social-ecological systems of the Colorado Plateau, and to identify strategies to mitigate deleterious consequences of these activates now and into the future. 

Two plugged and abandoned well-pads and associated vegetation reference communities.

Two plugged and abandoned well-pads and associated vegetation reference communities (summer of 2015). Click on image to enlarge. (Credit: Travis Nauman, USGS, from Nauman et al. (2017)

Background & Importance

Understanding how land use trends impact overall ecosystem and human health is important to managing the vast rangelands of the Colorado Plateau. The region includes spectacular canyons and mountains that draw tourists from around the world. There are also abundant mineral and energy resources that have been extracted since the early 20th century. These land uses often clash and the more than 3-fold increase in annual oil and gas exploration between 1990 and 2010 has disturbed large areas of delicate vegetation and biological soil crust on the Plateau. This begs the question of how quickly these areas recover from the clearing and leveling process associated with the construction and operation of oil and gas well-pads. Increasing levels of dust have been noted in the region since Anglo-colonization due to increased surface disturbance, and the dust has been linked to earlier run-off from the Rocky Mountains in Colorado leading to evaporative losses from the Colorado River – the water supply for tens of millions. So, the goal of this project is to assess the current scope, status, and recovery of lands disturbed by oil and gas development within the context of predicted future droughts. The assessment with then be used to help better plan oil and gas development, and begin testing best rehabilitation methods to restore ecosystems and prevent dust production.

General Methods

DART method flowchart

Method flowchart showing the Disturbance Automated Reference Toolset (DART) process of assessing ecological recovery. Uses example from a well-pad near the Four Corners region of the Southwest. Click on image to enlarge. (Credit: Travis Nauman, From Nauman et al. (2017)

Assessment of oil and gas pads required an automated approach because there are over 90,000 records of development on the Colorado Plateau. Data from newly created digital soil maps, topography models, and satellite imagery derived geology and vegetation indices were utilized to create a Disturbance Automated Reference Toolset (DART). Since it is impractical to visit 90,000 sites, DART allows use of satellite data to compare vegetation at similar sites nearby to each oil or gas well pad to gauge recovery. A smaller sample of field observations is then used to validate results from DART to make sure they are accurate in assessing vegetation recovery. The assessment from DART is converted into a quantile scale (0-100%) can be compared across large numbers of sites to look at trends in recovery – e.g. sites in certain vegetation types might not recover as well. These trends can then help land managers target areas that need more attention.

Important Results        

Well-pads on the Plateau plugged and abandoned between 1997-2005 (~1800 sites) were analyzed after their locations and actual development were verified in Google Earth Pro. DART showed that half of these well pads were below the 20th percentile relative to local vegetation. Over 30% of pads were below the 10th percentile. Well-pads with poor recovery tended to be found in areas with precipitation dominated more by summer monsoons, grasslands, blackbrush (Coleogyne ramosissima) shrublands, and state administered areas. Validation results showed that DART was effective at showing trends in total foliar cover and bare ground exposure, key variables in rangeland health. In particular, DART is good at highlighting areas recovering very poorly with large amounts of exposed bare ground and sparse vegetation cover.

Future Directions

The broad scale evaluation of oil and gas with DART is being expanded to areas outside of just the Colorado Plateau through development of the underlying data needed to run elsewhere. This process can be applied to a variety of land use disturbances and treatments for monitoring.

The evaluation of well pads is also being used to help our land management partners start prioritizing restoration and to guide further science to test effectiveness of rehabilitation techniques being employed at these sites.

References Cited

Nauman, T.W., Duniway, M.C., Villarreal, M.L., and Poitras, T.B., 2017, Disturbance automated reference toolset (DART): assessing patterns in ecological recovery from energy development on the Colorado Plateau: Science of the Total Environment, http://dx.doi.org/10.1016/j.scitotenv.2017.01.034.

Modern well-pad near Canyonlands National Park, Eye in the Sky District in a dry shrubland.

Modern well-pad near Canyonlands National Park, Eye in the Sky District (summer of 2016). (Credit: Travis Nauman, USGS. Public domain.)