Both surface water and groundwater may be adversely affected by drilling operations. Surface waters may be dirtied by increased sediment levels due to erosion, increased flows from runoff, and by the construction of road crossings. Stream beds may be altered by changes in the volume or location of flows that feed streams. Water quality may also be affected by leaks or disposal of wastewater from wells. Groundwater may be contaminated if drilling fluids and chemicals from the well hole escape into underground reserves, or minerals migrate between geological formations during drilling. Pipeline or storage tank leaks, leaks from mud pits, or wastewater disposal by injection wells may also contaminate the groundwater in the area of the well. If the groundwater feeds surface water, the contamination may also spread to neighboring bodies of water. BLM/FS have a duty to ensure that their leasing decisions will not lead to violations of water quality standards and other provisions of state water quality programs. The agency cannot simply claim that it has no evidence of water quality violations. BLM/FS are responsible for gathering the needed data and determining the likely impacts of oil and gas operations on water quality.
Your state water pollution control agency can provide a copy of the water quality standards that apply to the streams you are interested in. The state agency will also know if any streams have been designated for special protection under its anti-degradation program. BLM/FS must also guarantee that existing water quality in such streams is maintained or improved, even if it is already better than the standards. Also ask BLM/FS for copies of all water quality monitoring data for the streams in the area you are interested in, and compare those data with the standards to see if the standards are being violated. If water quality data is lacking, BLM/FS should use computer models, past experience, comparisons with similar, nearby watersheds, or any other reasonable and available techniques to estimate impacts on water quality. If the impact of a proposed action on water quality cannot be predicted, then the Forest Service should not take the action. The Clean Water Act requires that BLM/FS must modify or abandon the action if necessary to ensure that water quality standards will not be violated.