Cortes Island is experiencing a wetter than normal Spring this year, but some of Cortes Island’s shallow well owners experience water shortages every summer. Scientists appear to agree that there will be more severe shortages in the future. 

This is a global phenomenon and there appear to be many causes: the depletion of forest coverage, growth of human infrastructure, natural drought cycles and, on top of all that, the transition to a warmer global temperature.

During the drought last year, Ashlee Jollymore, a Hydrologist with the Water Management Branch in Victoria explained, “Summer is very typically a very dry time of year for the Island, as well as for the Gulf Islands. The problem is that because we didn’t get the Spring rains, we are starting at a level that is lower than what it would be within a typical year.”

John Preston moved to Cortes Island 19 years ago and has seen indications the water table has been dropping. 

“When we moved to Cortes Island a dear architect friend who looked over this property for us said, ‘you will need water.” 

“I said, ‘Okay. we’ll drill a well.’” 

“He said, ‘Please do not drill a well. Have a high quality surface well. Every well we drill now ultimately weakens our long term water aspect.’”

Preston agreed and now has a 27’ deep surface well, but the water situation appears to be worsening.   

The marshland above his property used to remain swamp all year round; now it is dry during the summer. 

Preston dealt with water shortages every summer since 2016, but 2021 was the worst. The water shortages he is usually confronted with in late August arrived in July.

“We are four weeks early in our water deprivation and there is a chance our water deprivation will go longer into the Fall than usual,” he said.

Preston believed the problem was drilled wells emptying the aquifer.

Red Williams, who drills wells on Vancouver Island, the Sunshine Coast, Quadra and Cortes Islands, said he has heard this idea before, but never encountered a collapsed aquifer. He said shallow wells run out of water during dry spells and are replenished when the rains return. 

“Yes, I agree with him,“ said  Dr Diana Allen, the head of the Groundwater Resources Research Group at Simon Fraser University. 

She has heard of this occurring in places like California’s Central Valley and Mexico City, but not British Columbia. 

“When you take ground water out of an aquifer that consists of interlayers of sand and clay, there is the potential for the clay to lose whatever water it has in it and squish. That can cause subsidence,” explained Dr Allen. “You have to take a lot of water out … huge quantities, or also where oil and gas have been taken out of deep sedimentary rocks … but for small aquifers, like what you would find on Cortes Island, I do not think subsidence would be a real problem.” 

Checking the iMapBC website, Allen discovered that most of Cortes Island’s known aquifers are in bedrock where subsidence is not an issue.

 All three of the aquifers that cover much of Whaletown (#843, #844 & #845) are in bedrock. 

Aquifers #842 and #846, which feed the area between Mansons Landing and Cortes Bay, are in rock. 

“So it is really only this southern tip. All the other areas that have been mapped with aquifers show bedrock,” said Allen.

Aquifer #841 which feeds most of the land between Mansons Landing and Sutil point, is sand and gravel. 

“When the glaciers were all melting, they would have dumped a whole bunch of sand and gravel on this point. This is actually a confined aquifer, so there is some clay over the top of it that is providing natural protection to that aquifer. So this would be a good quality aquifer,” she explained.”

The aquifers feeding more than three quarters of Cortes Island – Tiber Bay, Squirrel Cove and all the lands in the north – are not mapped. 

Allen explained that this would have been because this area is so sparsely settled. 

The 2002 geological survey of Cortes Island map show that most of Squirrel Cove is sand, mud and gravel, but the rest of northern Cortes is primarily rock.

So, if Cortes Island’s aquifers aren’t collapsing, how do you explain the wetland, that used to be filled with water year round and has dried up the last few summers?  

She explained, “That’s where climate change comes in.”  

I asked Dr Allen if the problem is drilled wells. That is probably too specific. Scientists are finding that the depletion of the world’s forest cover and growth of human infrastructure are causing global water shortages. 

Miranda Cross, Project manager for the Dillon Creek Wetlands Restoration, explained, “Forestry, agriculture and residential developments are our main threats to ecosystems on Cortes Island. Many residential homes are built in wet places so they drain the landscape. It’s such a common practice that I don’t even know that people recognize it as draining wetlands, but  every time a ditch is dug that moves water, a wetland is being drained or a stream is being straightened. The impacts of that are great, especially in densely populated areas.”  

Cross said that the Lower Mainland has lost 90% of its wetlands and the range is 60% to 90% throughout southern British Columbia. 

“On Cortes we’re not as densely populated. We still have some remaining intact wetlands around. So we’re probably closer to 60%,” she said. “Everywhere I walk on Cortes Island, I see ditches and drained wetlands.”

The iconic western red cedar is among the species now forced to cope with a lowered elevation of groundwater in its habitat. 

“That’s why restored wetlands can be so crucial for this species,” said Cross. “We are bringing the groundwater levels back up, rehydrating and resaturating the soil.”

A few years ago, a University of Victoria study of tree ring data found that BC has gone through 16 droughts exceeding anything in the more recent instrumental record. 

One of the study’s co-authors, Dr Bethany Coulthard, believes we are underestimating the potential impact of a mega-drought. 

She explained, “When you look at how severe droughts can get and then you add climate change and land use change on top of that, it would be reasonable to expect that when one of these extreme events does happen it will be more severe than anything that has happened in the past 350 years. We will almost certainly experience droughts worse than last year in the decades to come.”

Jollymore was familiar with this study.

“I think when we get into the mega-drought situation, what we’re really looking at is multi-year precipitation deficit. So multiple years in which we don’t get the rain, or the snowpack in the areas that need a snowpack, and that persists over a long period of time,” she said.

“If those precipitation deficits continue to persist over the winter, into next year and the year after – that’s when I think those mega-drought definitions kick in. Hopefully we don’t get there.”

This may be happening in California, but not yet in British Columbia.

Studies of the tree rings throughout the Americas, have found evidences of mega-droughts that were much worse than what we have seen and suggest there will be another mega-drought sometime in the future. As Dr Coultardt said, the next one will probably come with the additional impact of climate change. 

Top image credit: Photo by Geetanjal Khanna on Unsplash 

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