The EPA has been investigating water quality concerns in private drinking water wells in Pavillon since 2008. During the last several years, the community of Pavillion, the state of Wyoming, and the owner of the gas field, Encana Corp., have joined EPA to assess the water quality and identify potential sources of contamination. After meeting with the Wyoming Department of Environmental Quality, EPA began sampling drinking water wells in 2009; a second sampling took place last year.
The testing involved constructed two deep monitoring wells to sample water in the aquifer. The draft findings indicated that the groundwater in the aquifer contained compounds likely associated with fracking, according to the federal agency. It also re-tested private and public drinking water wells in the community and found the samples were consistent with chemicals identified in earlier EPA results released in 2010 and are generally below established health and safety standards.
Another important point emphasized by the federal agency is that its draft findings are “specific to Pavillion, where the fracturing is taking place in and below the drinking water aquifer and in close proximity to drinking water wells — production conditions different from those in many other areas of the country.”
Indeed, there are major differences between the the fracking process in Wyoming and here in Colorado.
The wells in Pavillion were drilled to a depth of about 1,200 feet, and the surface casing — pipe to protect groundwater — went to roughly 360 feet, leaving part of the aquifer exposed, according to the EPA report. In Colorado, wells are drilled to oil-and-gas zones 6,000 to 12,000 feet deep, except for shallower coal-bed methane wells.
Colorado rules require that surface casing extend below the aquifers, which are usually no more than 1,000 feet deep, and the casing must be surrounded by a cement jacket.