We are nearing the completion of construction of our second breach in the North Arm jetty to restore fish passage for juvenile salmon. This 30-meter wide breach will allow juvenile salmon access to Sturgeon Bank from the North Arm of the Fraser River, re-opening movement pathways that have been altered for over a century.
This project is a major construction undertaking, requiring us to move a large amount of sand material and place a significant amount of rock to create a stable breach and jetty that will continue to function for many years to come. This comes after our first breach was successfully built back in February of 2022, which we have monitored for two years and observed high rates of juvenile salmon passage during the spring outmigration.
Construction has occurred over the past two weeks and has gone quickly, with crews working overnight during the low tides to excavate the material and place rock towards the final configuration. The jetty was constructed back in the early 1900’s and this was paired with dredging of the river bottom, the material from which was sidecast onto the jetty and makes up much of the material that we are now moving. The material is not being taken off site, but simply moved to the area between the two breaches where it will become part of the jetty, and support the coastal sand dune ecosystem that existed there before.
Once the breach is completed, we will be monitoring fish passage at the sites for the next two years, starting just a few months from now in late March and sampling across the spring and summer of each year. We will also monitor changes to sediment patterns both in the river through sounding surveys and on the banks and in the breach through LiDAR surveys conducted annually at low tides.
Based on our experience and modeling results we anticipate this breach to function well as intended without any noticeable changes to navigation in the river as required by our permits. With this project coming to completion it marks the end of our connectivity restoration work in the estuary for now, with three 50 meter wide breaches created in the Steveston jetty from 2019 to 2021 and two 30 meter wide breaches constructed in the North Arm jetty from 2022 to 2023.
Moving forward, we are currently looking at opportunities to restore marsh habitats in the Lower Fraser River and estuary to work towards a greenway of connected habitats for juvenile salmon during their downstream migration.
Thank you to our project partners, Ducks Unlimited Canada, Lower Fraser Fisheries Alliance, and Tsawwassen First Nation. Thank you to Musqueam Indian Band, Metro Vancouver, and the Vancouver Fraser Port Authority for their support.
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