Assessment of Natural Gas Pipeline Construction on Stream Temperature and Turbidity in Southwestern Virginia, 2017—25

Brendan Michael Foster, Carly M Maas, Alejandra L Flota

The natural gas pipeline network in the United States is extensive and often intersects streams and other sensitive habitats, yet there are limited case studies utilizing a comparative upstream-downstream approach to evaluate potential short- and long-term effects of pipeline stream crossing construction from pre-construction to post-site restoration. In 2017, the U.S. Geological Survey, in cooperation with the Virginia Department of Environmental Quality (DEQ), deployed real-time continuous stream monitoring stations upstream and downstream of six proposed Mountain Valley Pipeline (MVP) stream crossings in southwestern Virginia. Water temperature and turbidity data collected at the upstream and downstream sites were compared across three periods – before crossing construction, during crossing construction, and after crossing construction – to elucidate potential impacts from the stream crossing construction. Additionally, the monitoring network was utilized to notify regulators of potentially anomalous conditions throughout the entire monitoring period.

Results of this study indicate (1) at all six monitored streams, pipeline stream crossing construction did not affect long-term or short-term upstream-to-downstream water temperature conditions; (2) pipeline stream crossing construction did not affect long-term upstream-to-downstream turbidity conditions in all six monitored streams. Some short-term anomalously elevated turbidity conditions were observed and attributable to pipeline stream crossing construction; however, the duration and magnitude were not sufficient to alter the long-term turbidity regime of the streams in which they were observed; and (3) the application of the monitoring network as a real-time alert system successfully alerted regulators to potentially anomalous conditions.