The decommissioning of several dams near Squamish this month spells good news for Britannia Creek's recovering marine life.
The deteriorating Park Lane and Utopia Lake dams once used to power the Britannia Mine have been decommissioned roughly 100 years after they were built. Provincial crews have removed 10-metre-wide sections from both dams, allowing the creek to flow freely along its natural creek bed once more. A four-metre wide, nine-metre-deep notch in another dam, Tunnel Dam, was also cut, effectively reconnecting two fish habitats that have been separated for a century.
"It's a positive move and exciting to see the watercourse being restored a little bit to what it used to be," said Squamish River Watershed Society executive director Edith Tobe.
At its peak in the 1930s, the Britannia Mine was the largest copper mine in the British Commonwealth, producing around 7,000 tonnes of ore per day, according to Britannia Mine Museum education coordinator Kevin Meisner. Acid runoff from the mine, which closed in 1974 after seven decades in operation, has caused pollution problems in Howe Sound for years.
"Interestingly enough, you can get caught in a bind here in saying what the impact was because it's still being figured out," Meisner said. "Up until the mine closed, they were doing copper laundering, so the copper was already being removed when the mine was operating. Its real impact didn't kick in until the '80s, well after the mine closed."
Victoria began dealing with pollution at the site in earnest in 1997 with the introduction of its Contaminated Sites Regulation. Clean-up efforts since then have led to the recent return of fish to a creek that was "basically a sterile and dead watercourse" during the mine's heyday, said Tobe.
"From a fisheries standpoint, it's all very new to us that the salmon are coming back at all to the lower reaches of Britannia Creek in the last five to six years, so any improvements by removing these obstructions will only benefit the downstream habitat," she added.
The decommissioning should also benefit other wildlife in the area by adding crucial wetland habitat to the creek, benefiting species like "the red-legged frog and potentially tail frogs in the upper reaches of the watershed," Tobe noted.
The rejuvenation of the area's marine ecosystem has been a surprising and welcome development for conservation groups. Howe Sound has not only seen the return of species like whale and dolphin, but the foreshore along where Britannia Creek and other tributaries enter the sound has become something of a "salmon highway" in recent years.
"There's also potential for seagrasses, such as eelgrass, to become re-established at the mouth of the creek," Tobe said.
Along with the ramifications for marine life, the decommissioning of the dams should significantly reduce the risk of flooding in Britannia Creek.
"The biggest risk was that they would fail in an earthquake," explained Bruce O'Neill, project director of provincial dam interests for the Ministry of Forests' resource stewardship division.
The province has future plans to either widen the notch and fully decommission the Tunnel Dam or renovate the dam to create a debris barrier. Ultimately, that decision will depend on the plans of the developer of the old Britannia Beach townsite, MacDonald Development Corporation, which has a proposal into the Squamish-Lillooet Regional District for a commercial project on the site.
"They're looking at putting in a debris containment barrier, where it goes is up for debate," O'Neill said. "The Tunnel Dam is one possible location but there are other possible locations as well. It's a matter of economics."
The nearby Mountain Lake dam will be decommissioned next summer. The province is also consulting with stakeholders to determine the best course of action for the Mineral Creek, Lower and Thistle Creek dams.
Britannia Creek has a history of flooding, with the most recent debris flow occurring in 1991.