On one occasion, while sailing through the Mamquam Blind Channel, David Crewson encountered an inconvenience that could've been, under different circumstances, catastrophic.
His sailing vessel was blockaded by debris.
"We're coming back and some debris — it was not even that much debris — had crossed over that channel," said Crewson. "And it was a falling tide. We were not able to get through that channel just because of the debris in the way…It was impassable."
There was one opening where the boat might have been able to sneak through, but there was a catch — that bit of water was only one foot deep.
The result, said Crewson, chief mate of Canadian Coastal Sailing, was an annoyance on that occasion, but it could prove to be a life-or-death matter under different conditions.
For instance, Crewson, who offers tours of Howe Sound, has had to rescue people whose vessels had capsized on the glacier-fed waters in Howe Sound.
When a person is removed from the hypothermia-inducing waters, every second counts. An indefinite blockage of the channel could have dire results for anyone caught in emergency situations.
It wouldn't just be Canadian Coastal who would have this issue. The Mamquam Blind Channel serves as the safe harbour for many of Squamish's vessels, and this could be a problem for many in the community.
"I think what we risk at the moment is the Blind Channel — our safe harbour," said Crewson. "And regardless, if you're a sailing vessel or a power vessel, the amount of sediment that's being washed into the Blind Channel every year from this — it's not only reducing the depth, but also the width of that navigation channel."
For example, this could pose a significant problem to visiting vessels operated by boaters who aren't as familiar with local circumstances.
"One of the risks that we have is also the current navigation aids," said Crewson. "So we have a range marker, which is basically a couple of lights that you align in order to enter the Blind Channel. People visiting Squamish don't realize that those nav aids take you right onto the sandbar. So it's all part of the bigger picture. And so the last thing that we want is to have people grounding their vessels as they approach Squamish for the first time."
This will be more and more of an issue as more people visit the town, he said.
In the meantime, the District of Squamish has recognized the need for dredging of the channel.
On April 12, manager of municipal infrastructure David Roulston told council that the last major dredging project for the channel occurred in 1986.
Since then, there have been some stop-gap dredges, most recently an operation that occurred in 2013. Another dredge is due soon.
"It's recommended to dredge down to a depth of minus 2.6 meters," said Roulston. "That results in a total dredge volume of 68,000 cubic metres that would allow 81% of vessels to safely navigate through the channel at the lowest tides of the year."
There is also the possibility of dredging the channel even more, but the expense escalates very quickly, he said.
"We looked at minus 3.2 [metres]. And that would allow 95% of vessels to pass, but it nearly doubles the total dredge volume, which has very significant cost implications," Roulston said.
Roulston said that going minus 2.6 metres would concentrate dredging in two key areas of the channel.
"The first is at the mouth of the Stawamus River, which is to be expected, given the ongoing sediment that is being discharged through the river there," he said. "And then the second is further upstream, towards the northern extent of the navigational channel, near Blue Heron Marina, Marina Estates and the SEAandSKY development site."
There are also considerations about where to put the material that would be dug out of the channel.
The material could be disposed of at sea or disposed of on land.
Land disposal includes several options — using the material for land raising, land creation or habitat enhancement.
Roulston said disposal at sea is the least costly, adding up to $3.3 million. Habitat enhancement would cost $4.4 million. Raising existing land would cost $5 million, and creating new land would be the priciest, at $8.7 million.
He added that maintenance dredging would have to be done on an eight-year cycle, which would cost $1.5 million.
However, the content of the sediment does pose some constraints when it comes to disposal. Not everything can simply be dumped at sea at the lowest possible cost.
Roulston said that tests from the 2013 dredging show there are two areas of the waterway that have elevated levels of mercury and hydrocarbons.
"They're contaminated and wouldn't be suitable for disposal at sea or on land," he said. "All areas have elevated copper. This is due to the Britannia mine, the historic mine there, and that's common throughout all of northern Howe Sound and beyond.
As a result, sediment with mercury and hydrocarbons would have to be disposed of at a certified landfill.
Planner Sarah McJannet said before dredging occurs, the next step would be to consult with the community regarding dredging options.
This would involve creating a stakeholder working group that represents the broad interests of those who use the channel.
Some examples would be the Squamish Nation, government agencies, waterfront landowners and leaseholders, stewardship groups, community organizations, tourism, recreation, industry and more.
"The working group is seen as a valuable and effective method to involve a fulsome representation from across the community to advise on community values, priorities, directions and recommendations," said McJannet.
She said working groups are often used in these types of projects.
There's also the possibility for this working group to act as a pilot, and perhaps become an ongoing marine working group that would weigh in on matters concerning that realm.
Ultimately, municipal council voted unanimously in favour of directing staff to proceed with community engagement regarding dredging and initiate recruitment for a dredge program stakeholder working group.
Back on the waters, Crewson said that he's looking forward to having authorities address the situation.
"Frankly, anything helps," he said.
Crewson called for a system of periodic dredging maintenance, which would prevent the channel from the extremely low conditions that can occur at low tides nowadays.
He hoped a collaborative program between government, users, industries and others could help share the financial burden of the work.
It's especially important given the increasing popularity of Squamish's waters.
"What we're witnessing is access to our marine environment is increasing every year," Crewson said.
