The water pumped from the coal aquifer is usually discharged to existing stream channels. Many of these receiving streams are ephemeral or intermittent. Constructed ponds may receive some of the produced water that may in turn directly or indirectly discharge to an adjacent stream channel. Because coal bed methane extraction involves the continual discharge of groundwater to the surface, it may cause several substantial water quality impacts in the basin. Increased flows in these streams from discharge water may damage streambeds and destabilize stream banks.
Ephemeral streams are especially vulnerable to gullying and destruction of vegetation.
The chemical quality of the water is also a major concern. The quality of the discharged water varies from one area to another with a greater concentration of dissolved constituents near the Wyoming-Montana border. The discharge of CBM production water in Wyoming and Montana can increase the concentration of these parameters in our rivers and streams and impact beneficial uses. Montana has numeric standards to protect human health and has designated beneficial uses for many of these pollutants. This process will include a consideration of existing soils, irrigation practices and crops.