Can high volume hydraulic fracturing effects be detected in large watersheds? A case study of the South Fork Little Red River

To date, most studies focusing on the effects of high volume hydraulic fracturing on freshwater systems have been at the small watershed scale (i.e. <130 km2). Here we review the findings from the small watershed studies and present a case study of a larger watershed, the South Fork Little Red River (SFLRR) watershed (127-193 km2). Hydraulic fracturing within the SFLRR watershed resulted in no detectable changes in physicochemical parameters or algal biomass. However, sensitive macroinvertebrate taxa densities were reduced downstream of hydraulic fracturing relative to upstream. Increased distance from the hydraulic fracturing, in-stream processing of physicochemical properties, and additional landscape disturbances, likely made it more difficult to assess the effects of hydraulic fracturing in most stream response variables at the larger watershed scale.