Environmental Engineering Reference
In-Depth Information
springs or as base flow into stream channels, leading to surface water contamination.
Recovered waters used for hydraulic fracturing could cause altered surface water
quality or an increase in flows in normally dry water bodies such as ephemeral drain-
ages, if they are disposed of by discharge to the surface.
With regard to hydraulic fracturing wastewater discharge into the environment,
a point of interest is that the Clean Water Act (CWA) made it unlawful to discharge
any pollutant from a point source into the navigable waters of the United States
unless done in accordance with a specific approved permit. The National Pollutant
Discharge Elimination System (NPDES) permit program controls discharges from
point sources that are discrete conveyances, such as pipes or man-made ditches.
Industrial, municipal, and other facilities such as shale gas production sites or com-
mercial facilities that handle the disposal or treatment of shale gas produced water
must obtain permits if they intend to discharge directly into surface water. Large
facilities usually have individual NPDES permits. Discharges from some smaller
facilities may be eligible for inclusion under general permits that authorize a cat-
egory of discharge under the CWA within a geographic area. A general permit is not
specifically tailored to an individual discharger. Most oil and gas production facili-
ties with related discharges are authorized under general permits because there are
typically numerous sites with common discharges in a geographic area.
Land Use
Land use impacts during the operations phase would be an extension of those that
occurred during the drilling/construction phase; however, to some extent, land can
revert to its original uses after the major drilling/construction phase is over. For
example, farmers can graze livestock or grow crops around the well sites. Other
industrial projects would likely be excluded within the sequestration project area.
Recreation activities (e.g., OHV use, hunting) are possible, although gun and archery
restrictions would probably exist. Operations may conflict with livestock and farm-
ing operations.
Soils and Geologic Resources
Following construction and drilling, disturbed portions of well and ancillary facility
sites not required for operations would be revegetated. This would help to stabilize
soil and geologic conditions. Routine impacts on soils during the operations phase
would be limited largely to soil erosion impacts caused by vehicular traffic. Any
excavations required for maintenance would cause impacts similar to those from the
drilling/construction phase, but to a lesser spatial and temporal extent. The acciden-
tal spill of product or other wastes would likely cause soil contamination. Except in
the case of a large spill, soil contamination would be localized and limited in extent
and magnitude. In areas where interim reclamation is implemented (e.g., reclamation
of an individual well that is no longer needed), ground cover by herbaceous species
could reestablish within 1 to 5 years following seeding of native plant species and
diligent weed control efforts, thus reducing soil erosion. Operations might preclude
or interfere with mineral development activities in the project area, including oil and
gas development and mining activities. Possible geological hazards (earthquakes,
landslide, and subsidence) could be activated by injection activities.
