Water

Mapping Wetlands on Quadra, and what that means on Cortes

The ICAN water security team and We Wai Kai Guardians are getting prepared to map Quadra Island’s wetlands. It is part of a much larger project which also involves monitoring the island’s rainfall, streamflow and wells. As you will hear in the interview that follows, this project is also relevant  to surrounding islands like Cortes. Bernie Amell, a recognized authority in the design of constructed wetlands for water treatment, and in the restoration of streams and riparian habitats, is in charge of mapping the wetlands. 

Screenshot of Bernie Amell taken during our ZOOM interview.

“Three or four years ago, we started being concerned about climate change and how it would affect the water cycle. This is a temperate rainforest country and we’re already seeing with the cedar trees, a change in their range and healthiness.  So there’s environmental reasons for being concerned, but there’s also the human use factors. At what point do you say,  ‘we basically can’t have more human use?’ The sponge doesn’t have more water in it,” he explained.

Satellite image of Quadra, Cortes and other Discovery Islands – courtesy Google Maps

“We hear all kinds of horror stories about Pender Island, Salt Spring and Hornby. They’re actually in much more serious immediate trouble as the climate changes because they don’t have as good an aquifer development. I’m not saying  that’s the point that Cortes or Quadra are at, it’s just not knowing is  an uncomfortable place to be. So four years ago, we started looking at that  in the big picture:  climate change,  wetlands, and the aquifers.” 

CC: How far along are you in the wetland project? 

Bernie Amell: “Right now  we’re developing a field guide for citizen science teams to go out and use mainly plants, but also other ways of looking at the terrain for clues as to where the permanent wetlands are, where the seasonal ones are, where there are impermanent streams.”

“The team has separate project teams. Eileen McKay is very strongly involved in this and there’s a couple of other people who are knowledgeable in native plants and they’re providing their expertise in developing this guidebook. Then we’ll just hit the ground and go out and recruit people to come and bushwhack with us.”

CC: Should people in the surrounding islands, like Cortes, be interested in this mapping project?

Bernie Amell: “It’ll actually be quite relevant.  The more settled areas of Cortes are in the same kind of terrain that I’m talking about. The land that’s farmable,  where there’s some soil and you can actually grow things, is  glacial silt deposited stuff. You’re probably very very similar to what we’ve got here and also the plant community is similar. I’ve been bushwhacking a little bit there, and the terrain and parts of Cortes is very similar  to what we see here.” 

“During the wet season you have a lot of streams that all run across the landscape, and that’s a very important pattern to understand. Remember the diagram of the water cycle that you learned in junior high school?   Between the atmosphere, the rain coming down and the aquifers, there’s this zone where some of the water runs right off, but some of it infiltrates.”

“We need to understand how that works in our particular island and maybe our own property.”

The southern tip of Cortes (yellow) is ‘sand, mud and gravel’ similar to what you find in Squirrel Cove and southern Quadra Island. The other colours are rock types. – Map courtesy Geological Survey of Canada

“I want to talk a little bit about the special character of the terrain on South Quadra Island and South Cortes. It’s very special, unusual terrain. It has a very low permeability layer, maybe a half meter down. People refer to it as clay, but it’s actually  highly compressed glacial silt. During the wet season, It perfectly forms horizontal flow. It resists the water going down, it moves sideways through the soil. It’s a form of wetland called a wooded fen,  it tends to be high in nutrients, and grows trees really well.”

“Because of that impermeability below us, it’s particularly important to understand there are places in the landscape where it is possible for the water to go into the aquifer below that. There’s variations in the landscape. One part of the island and another, and maybe even between one property and another. There’s variations in how much the water can soak into the ground.” 

“One of the aspects of mapping wetlands is to map permanent wetlands and seasonal wetlands, because the seasonal ones might be very important for replenishing the deeper aquifers.”

CC: I’m particularly interested in a problem we’ve had on Cortes Island the last couple of years. The flow of Basil Creek, in Squirrel Cove, has been reduced to a trickle in the summer. This has prevented most of the Chum from returning to spawn. Some of the shallow wells have been running low and this past summer at least three of them stopped recharging for months.  

There are unexpected turns in almost every interview, and sometimes I find myself referring to a piece of evidence that I can only vaguely remember.  The 2002 survey depicts large segments of north and central Cortes as rock. I mentioned this to Bernie but now see that, like the southern tip of the island, Squirrel Cove is largely depicted as mud, sand and gravel.

When I suggested that it was rock, he replied:

“One of the things I would say is, you need to really map that creek and  understand where the seepage flows are feeding that creek. I don’t think the entire watershed is going to be rock. There’s going to be thin soil areas and then also the same hardpan that I talked about.” 

“Usually if you see alder trees … there’s a bit deeper fine soil available to them.” a seasonal wetland along Pidcock Creek near Quathiaski Cove Ferry.  Note the very robust growth of Skunk Cabbage, which is a good seasonal wetland indicator plant. – Photo courtesy ICAN water security team

“Usually if you see alder trees in this landscape,  there’s a bit deeper fine soil available to them, but also they don’t like to be completely wet. So they’re not right in  the heart of the  swamp.”

“Parts of Quadra have issues with shallow aquifer depletion. There’s at least two layers of aquifer. One is the shallow layer that’s near the surface, or three, four meters down. People can tap into it  for a well and that’s what often feeds these smaller creeks is that shallow area.”

CC: While he couldn’t speak directly to the situation in Squirrel Cove without examining the problem, Bernie mentioned some of the causes of water depletion in shallow wells and creeks.

Bernie Amell: “One of the things that people can inadvertently do when, say they’re making a farm or  putting in a house or something, they’re ditching because they want to dry an area out so they can  have access. I’m not saying this happens all the time, but you can inadvertently subtract that water from a place where it could soak into the ground by putting in a ditch. Maybe you need to put the ditch so that it then discharges to another low point somewhere, where you allow the water to soak into the ground. But that’s getting into the fine grain detail of where we might get to by understanding the wetlands and  other surface water, like ditches and natural rivulets and that sort of thing.”

“Any significant road has ditches, probably on both sides.  You have to do that or the road essentially is overwhelmed.  It has never been a thing for the engineers that build the road grades to be all that concerned about where that surface water is going. It’s a matter of, ‘I don’t want it on my road.’ You don’t want it on the road because, of course, it makes it impossible to drive at certain times. Changing the surface water movement patterns is often an unforeseen side effect of land use development.”  

CC: Someone was suggesting that Basil Creek’s issues might have something to do with the wetland at the headwaters. There have been questions about problems with beaver dams up there. I wish I could remember clearly, they might have been ripped out.

Bernie Amell: “That  is very site specific. Beaver dams are good, they do feed shallow aquifers.  They may be inconvenient at first for the land user, but there are very strong environmental benefits to them. It’s possible to have some kind of flow exiting restraint on it, the human equivalent of a beaver dam.”

CC: Is the problem we’ve had with the waterflow in Squirrel Cove reversible? 

Bernie Amell: “It’s a kind of micro thing, it’s going to be very specific to the terrain you’re on. Yes, it could be reversible, but it needs enough people getting along with the program and saying, ‘okay, I can take my ditch and put it over there so it actually soaks in the ground rather than just running away.’ You want to have that water on the surface long enough that it has time to soak in.”

A beaver dammed portion of Drew Creek.  This wetland helps to maintain flows in the creek – with beneficial effects for many species including salmon.- Photo courtesy UCAN Water Security Team

CC: Do you have anything you would like to say to the people listening to this program? 

Bernie Amell: “One of the benefits of being on Cortes or Quadra is there is a deep aquifer in places and if you’ve got a blessing,  you don’t just  take it for granted. You come to understand it so you can be the proper steward of it.”

You’ve been listening to an interview with Bernie Amell, who’s heading the wetland mapping project on Quadra Island. He also made a couple of suggestions about the water depletion problem in Squirrel Cove. The most important being: “you need to really map that creek, and  understand where the seepage flows are feeding that creek.”

Top image credit: an unnamed seasonal creek in the midline of South Quadra, which discharges to the sea near Tsakwaluten Lodge – Photo courtesy ICAN Water security team

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