Given that produced water can be treated to any water quality with current technologies but at widely varying costs, future regulation of CBM produced water management should consider the age of the CBM produced water. Careful management of nonrenewable “fossil” water, after extraction, for best nonrenewable resource use should be considered a priority.
Costs of water treatment, storage, and transport are not negligible, but current regulations and water law do not allow CBM operating companies or other stakeholders many options to consider other than disposal of fossil (nonrenewable) CBM produced water of relatively poor quality through deep-well injection. This kind of water management is not and should not be considered a beneficial use of the water resource. Even in cases such as the Powder River Basin where CBM produced water contains relatively low dissolved solids concentrations, the full range of beneficial use options is not exercised, partly due to economics and partly due to the restrictions of existing water law.
Each beneficial use aligns with a set of criteria and acceptable or appropriate criteria for one beneficial use of CBM produced water may be in direct conflict with the criteria for another beneficial use. Additional complications are introduced when consideration is given to liability, water rights regulations, and sustainability of supply issues. These circumstances, in addition to the general decrease in volume of CBM produced water over the lifetime of a well, make CBM produced water an uncertainty and only a temporary source of water for beneficial use. This uncertainty contributes to the difficulty of addressing opportunities for beneficial use.
Recent litigation and changing case law in some western states related to CBM produced water management signal that various stakeholders now recognize the fact that water resources traverse state, legal, and geological boundaries. CBM production in the United States currently constitutes about 10 percent of annual domestic dry natural gas production and is predicted to grow as the nation considers the transition to a less carbon intensive energy resource base, of which natural gas is considered a cornerstone. Integrated approaches toward water and energy use and conservation are increasingly being considered as environmentally and economically sound. Multiple potential users and uses of limited water resources, a concern by the public for protection of these limited resources, the complexities of hydrogeological systems, and the renewability or nonrenewability of water resources require increasingly sophisticated approaches to CBM produced water management. These approaches require a basis in scientifically grounded studies and consistent monitoring and should allow for a greater range of economically and environmentally viable options for CBM produced water management.