Sediment Patterns in Streams with Run-of-River Hydropower Projects

Run-of-river (ROR) hydropower has become increasingly popular as an alternative form of energy production, touted as more environmentally friendly than traditional dams. While this may be true, there is little scientific evidence to support or refute these claims. Some concerns regarding ROR hydropwer is the introduction of a migration barrier for aquatic species, increases in temperature downstream of the headpond, and alterations to sediment transport. Both increases and decreases in fine sediment deposition have been shown to have deleterious biological effects and it is therefore important to determine if fine sediment deposition is changed during normal ROR operations. To compare regions above and below ROR dams, we collected biofilm samples, sediment size frequency data, and embeddedness levels above and below dams at three different locations near Harrison Lake, British Columbia. Our results suggested that embeddedness was higher below the dam at one site, which may indicate that individual stream characteristics play an important role in the degree of embeddedness downstream of ROR dams, although this trend did not result in any significant differences in biofilm quality.