Eve River Fish Habitat Offsetting Remediation Project

Client

BC Ministry of Transportation and Infrastructure

Location

Vancouver Island, British Columbia (north of Sayward)

Project Duration

August 2019 – ongoing

Background

As part of the Eve River Bridge Erosion and Scour Protection Project, fish habitat enhancement features (large woody debris complexes) were installed upstream and downstream of the Eve River Bridge to create areas of refuge for migrating fish and to provide summer rearing and overwintering habitat for salmonids. Fisheries and Oceans Canada (DFO) and Hatfield expressed concerns about how the fish habitat offsetting features were functioning because of limited fish access to the large woody debris complexes and influences from bedload movement and channel migration.

Services Provided

Hatfield assessed the Project site during low flow and high flow conditions in 2019 and 2020, to assess the efficacy of the constructed fish habitat features and subsequently worked with MOTI and the design team to develop a remedial work plan to improve the effectiveness of the habitat features. The focus of the remedial work was to improve the function of the large woody debris complexes, each comprised of three large logs cabled together and anchored with boulders. In August 2020, Hatfield oversaw and directed remedial works including gravel excavation and relocation of the large woody debris complexes, so that they are connected with the mainstem channel during low flows, accessible to fish, and promote scour of accumulated bed material. Hatfield re-assessed the offsetting features in 2021 and determined that they are now used by coho salmon, Dolly Varden and rainbow trout during both low and high flows. Hatfield also installed willow stakes along a relocated tributary to the Eve River to establish riparian vegetation and conducted a drone survey of the project area.