Impacts and recovery in a coldwater stream following a natural gas pipeline crossing installation

摘要

Findlay Creek is a small, coldwater stream which was crossed by a natural gas pipeline using conventional opencut techniques in late August 1992. Pipeline crossing activities included the removal ofa beaver dam which was located along the proposed alignment, the installation of a temporary road crossing, and the actual pipeline installation. A monitoring study was initiated to examine the impacts of pipeline construction on this stream including changes in the physical and biological regimes of the aquatic ecosystem. Results of this study indicate that the dramatic sediment loads (suspended sediment levels of up to 3000 mg/L) caused by pipeline construction were sufficient to cause changes to the channel morphology as well as the fish and invertebrate communities. By twelve weeks post-construction, partial recovery of habitats and aquatic communities was apparent. Changes to the physical channel parameters and the stream population structure documented in this study suggest that impacts to Findlay Creek were localized, and full recovery was documented in affected areas by the one year post construction sampling period. This study concurs with other research investigating the impacts of pipeline construction, in that impacts on the aquatic fauna appear to be localized in extent and short term in duration.