MONITORING IMPACTS OF NATURAL GAS DRILLING ON HIGH-QUALITY AND EXCEPTIONAL VALUE STREAMS, TIOGA, LYCOMING, AND POTTER COUNTIES, PA

Development of the Marcellus Shale natural gas play has been focused in areas of the Allegheny Plateau in north-central Pennsylvania. This region includes extensive parcels of State Forest land (the “Pennsylvania Wilds”) that host forested watersheds designated as High-Quality (HQ) and/or Exceptional Value (EV) based on PA Chapter 93 water quality standards. Streams designated as EV and/or HQ have a high sensitivity to surface water and erosion/sedimentation changes, and can provide indications of significant watershed impacts.

This study examines present water quality conditions in two similar watersheds on PA State Forest land (Elk Run and Slate Run) with the goal of establishing a baseline for ongoing monitoring and assessment as natural gas well development and production progresses over the next several years. The two watersheds under study both drain relatively steep upland regions of the Allegheny Plateau and share similar bedrock geology. The Elk Run watershed occupies 3.88 square miles within the boundaries of the Tioga State Forest. Soils developed in the Elk Run watershed range from well-drained with relatively large (> 2m) depth to the watertable, through relatively poorly drained with extensive shallow (< 40 cm) fragipans. Smaller studies may be conducted within these soil variations. Twenty-one horizontal gas wells have been permitted in the Elk Run watershed and are currently in development or production. The Slate Run watershed encompasses 5.43 square miles in total, spanning streams in Tioga State Forest and the adjacent Tiadaghton State Forest. Soils in this watershed are dominated by well-drained and excessively well-drained profiles with similar depth to the watertable of >2m. No gas wells are currently permitted in the Slate Run watershed, and leasing of mineral rights in this region is not planned. Water quality data will be collected at quarterly intervals over a five year period to assess impacts from surface runoff in each watershed. By tracking long-term changes in similar watersheds, the study will enable comparison of EV and HQ stream response to well pad construction and gas production in forested regions. In addition, monitoring impacts on water quality and aquatic organisms in forested watersheds may provide more apparent indications of potential watershed impacts in other regions.