History of the Wetland
When Sargeant Bay Provincial Park was established in 1990, the wetland between the bay and Redrooffs Road was in poor condition. In 1978 the previous owner had dredged a channel through the beach berm and into the wetland to create a marina. This allowed the tides to enter the area freely, causing logging debris to enter and soil to erode. During low tides the water-saturated soil compacted.
In consultation with BC Parks, the Ministry of Environment and the Department of Fisheries and Oceans, the Sargeant Bay Society developed a plan to rehabilitate the wetland. The plans approved in 1991 and carried out the same year. Financial support was provided by the Environmental Partners Fund and the Habitat Conservation Fund.
The Fish Ladder
The channel was filled in and a fish ladder was installed where Colvin Creek used to discharge into the bay before the dredging.
Because the compacted soil in half of the wetland could not be returned to its previous spongy state, Colvin Lake (a little lake with an island) was created as a refuge for birds and wildlife.
The creek was dredged out where it had silted up to provide access for salmon to the gravel beds below Redrooffs Road.
Impact of the Beavers
The same year the rehabilitation project was completed, Chum and Coho came to spawn in Colvin Creek. Also that same year beavers, that had settled in the wetland in 1998, decided that the lake we made was not a sufficient home for them. They started to build a dam in front of the fish ladder as well as in several other locations along the creek.
During the next few years volunteers removed the dams during the spawning season. This became too onerous and was discontinued. Only the dam in front of the fish ladder was removed during the spawning season. After that, Chum no longer spawned in the creek, although some Chum fry has been caught in the lake, upstream of the fish ladder.
The beavers kept expanding their system of dams as shown on the diagram below and built seven lodges. We don’t know how many of these are occupied. The biggest lodge can be seen from the beach berm at the location of the bench.
Eventually, removing the entire dam in front of the fish ladder, also became too much of a chore and only a channel, wide enough to let the salmon pass through, was dredged out. The dam has now become a permanent fixture. It raised the level of the lake by 42cm, as can be seen in the above diagram.