Baseline water quality in the Petitot River Basin and surrounding Watersheds

As part of a three year study funded by Environment and Climate Change Canada and Natural Resources Canada (ecoENERGY Innovation Initiative, project UOSGQ963; http://www.nrcan.gc.ca/energy/funding/current-fundingprograms/eii/4985) data were gathered to assess and monitor water quality conditions in northeastern British Columbia (BC). Defined in this datasetas portions of the Petitot, Fort Nelson, and Hay River basins, northeast BC is a region subject to both historical conventional oil and gas development and more recent unconventional oil and gas (UOG) development. UOG development in this area is presently focused on the Horn River Basin, Cordova Embayment and Liard Basin shale formations (BCOGC 2010, 2013a). Otherwise, UOG development in BC is centered in the Montney Play, located further south (Adams et al. 2016).

Surface water quality assessment and monitoring focused on two river basins in this area: the Petitot River Basin and the Fort Nelson River Basin. Baseline and/or best available surface water quality information was gathered from January 2012 to March 2015. Benthic macroinvertebrates were collected over the same period to complement the water quality study through development of a Canadian Aquatic Biomonitoring Network (CABIN) bioassessment model.

Routine Water Quality Monitoring study objectives were to gain a better understanding of water quality conditions in the Petitot River Basin by collecting baseline data using a standard suite of physical-chemical variables and establishing a representative long-term site. Routine water quality sampling sites were selected at locations with known exposure to UOG activity and varying watershed areas; submersible loggers were also installed to collect specific conductance and temperature data.

Synoptic Water Quality Monitoring study objectives were to establish patterns of spatial and temporal water chemistry through synoptic water sampling at high and low flow periods and examine potential relationships between UOG activity and surface water quality. Sample sites were selected at microbasin drainage outlets to represent a range of upstream activity and potential contamination. A series of samples were also collected along the mainstem Petitot River at 20-kilometre intervals from the Alberta border to the Highway 77 bridge to capture potential “step-changes” in water chemistry as the river flows through the northeast BC gas production area.

Biological Monitoring study objectives were to establish baseline reference conditions based on benthic macroinvertebrate communities and habitat characteristics, and develop a predictive bioassessment model to assess the ecosystem health of streams in the Liard, Fort Nelson, and Petitot River basins exposed to UOG activity. The biological monitoring study design followed CABIN sampling methodology for benthic macroinvertebrate collections in streams and rivers (Environment Canada 2012, http://www.ec.gc.ca/rcba-cabin). Sampling was conducted at 53 reference sites unaffected or minimally influenced by human activity. Thirty five test sites were also selected across a gradient of UOG activity, based on well densities. A preliminary predictive bioassessment model for northeast BC was established and is available through the CABIN website for future assessment of water quality and ecosystem health in the region.