Effect of oil pipeline construction on the benthic invertebrate community structure of Hodgson Creek, Northwest Territories

Abstract

During the ice-free seasons of 1984 and the winter and summer of 1985, we determined the effect of winter oil pipeline construction on benthic invertebrates of Hodgson Creek, Northwest Territories. Total suspended sediments increased from < 2 mgL−1 to > 300 mg L−1 at sampling stations downstream of the pipeline right-of-way during construction, with peak concentrations exceeding 3000 mg L−1. A concurrent increase in benthic invertebrate drift density from 2.6 to 37.6/100 m−3 was observed downstream of construction. The effects of pipeline installation were observed up to 5 weeks following the end of construction. Following the spring snowmelt in 1985, no significant difference in standing crop, species richness, or functional group composition between stations upstream and downstream of the pipeline right-of-way was observed. We concluded that the negative impact of pipeline construction was limited to the period between construction and spring ice breakup. The frequency and magnitude of spate events were sufficient to remove accumulated sediment. Thus, the impact of natural perturbations in Hodgson Creek was greater than the effect of pipeline construction on benthic community structure.