The Dillon Creek Wetland Restoration: What did they accomplish?

There was a celebration at Linnaea Farm on Friday, March 31. While they will continue to monitor the site until at least 2026, Cortes Island’s first wetland restoration project is largely finished. The surrounding community was invited to tour the project, enjoy a potluck supper and watch Beatrix Baxter’s documentary film ‘Replenish: Bringing Back the Dillon Creek Wetland.’

“We’re just at the end of a three year grant. The Environment and Climate Change Canada ‘Eco Action Community Funding Program‘ ends today. We have a little bit of funding for this next year of monitoring and maintenance and we’ll be pursuing additional funding for future years of monitoring and maintenance,” explained Project Manager Miranda Cross.

MIranda Cross showing visitors a ditch running alongside the wetland – Photo by Roy L Hales

“This project was initiated in response to the algal blooms that were witnessed, starting in 2014, in Hague and Gunflint Lakes. At the time, the Friends of Cortes Island Society (FOCI) and a group of concerned citizens got together and initiated a lake monitoring program, with support of the Ministry of Environment and the BC Lake Stewardship. They collected monthly data over a number of years and are still collecting data.” 

“When that data was analyzed by Limnologist,  Dr. Maggie Squires, in about 2018, her analysis revealed that it is likely phosphorous loading that’s creating the algal bloom in the lakes, and that our best strategy for mitigating nutrient inputs would be to restore wetlands on land adjacent to the lakes.” 

“At that time, FOCI approached Linnaea Farm, the biggest farm in the watershed. Because of their dedication to ecological stewardship, organic land care, organic farming, education and environmental stewardship, it was a really great fit and a really great partnership.”

“Friends of Cortes Island got in touch with BC Wildlife Federation, who put us in touch with Tom Biebighauser,  a wetland restoration specialist from Kentucky who does a lot of work here in the province. We were able to bring him to Cortes to look at the potential for wetland restoration at Linnaea and also at another farm on Gunflint Lake.” 

“Once we had the design report from Tom, we went ahead and pursued funding and eventually were successful in pursuing funding through the Eco-Action Community Funding Program.”

“Then we needed matching funds.  At that point we approached the community. We approached local individuals for support in terms of cash donations, and we also got in touch and made connections with so many of the local organizations who’ve been part of the project in terms of partnerships and educational programs or volunteer events. Through cash and in-kind donations, we’re able to raise the matching funds to go ahead with the project.”

Prior to being drained to make way for pasture, wetlands had filtered out the flow of nutrients into Gunflint Lake. Restoring the Dillon Creek wetlands was a three year project. Heavy machinery was brought in to rip apart the pasture, an inlet from the creek was dug out and native plants were reintroduced, 

MC: “The primary objective of the project was to be mitigating nutrient inputs, and then the co-benefit objectives were for wildlife habitat.”

 CC: One of your other objectives is wildlife habitat 

MC: “We’ve been doing water sampling which at this point, due to lack of sufficient data, is a little bit inconclusive. We haven’t been able to show from our water samples that there’s been a reduced nutrient input.” 

“However, what we’ve observed in the wetland that Dillon Creek is connected to, is a very substantial mitigation of soils and sediments that have been diverted from the lake and deposited in the wetlands instead.”

“There’s both silt deposits and sand and gravel deposits. We’re looking at about 560 yards, which is the equivalent to about 37 tandem size dump truckloads of material that have been deposited in the wetland from Dillon Creek.”

“So had the wetland not been there, that sediment would have ended up in the lake. This gives us an idea of just how much sediment and soil is being transported by the creek each year.”

 CC: To put this in perspective, what kind of difference would diverting that amount of sediment have made In terms of the original algae bloom problem?

MC: “I’m not a Limnologist, so I don’t feel qualified to answer that question. To me it seems like  a heck of a lot of soil and sediment. There’s not a lot of nutrients in sand and gravel, but there sure is a lot in silt.” 

“The agricultural land and valley bottoms that were historically floodplains are usually pretty high in silt and silt carries phosphorus. Phosphorus binds to silt  in the soil.”

“To break it down a little bit further, and I believe these are conservative estimates, the silt that’s been deposited in the wetlands over the last two years is about 470 yards, whereas the sand and the gravel deposits is about 90 yards.” 

CC: One of your other objectives is providing wildlife habitat, how has that been going? 

MC: “We’ve been seeing a whole array of wildlife,  alot of waterfowl, alot of amphibians like Tree Frogs and Red-Legged Frogs.” 

“When we started the project, we had five target species that we were hoping would benefit from the wetlands. They were: Great Blue Heron, Red-Legged Frog, Barn Swallow, Coastal Cutthroat Trout and Western Toad.” 

“We have seen four out of five of those species using the wetlands. Western Toads used to be very common on Cortes and Linnaea. No one’s seen one around here in a very, very long time, like in 15-20 years, but we just yesterday observed Red-Legged Frog egg mass, which we’ll see on the tour later today, which is really exciting. Red-Legged Frogs are a Species at Risk,  mostly due to habitat destruction and decline. We observed a Great Blue Heron eating a Coastal Cutthroat Trout in the wetland last week.”

“It’s just teaming with life. There’s so many invertebrates and tons and tons of birds and lots of wildlife”. 

CC: Can you put this in a global perspective? Wetlands are being lost around the world. In a previous interview you mentioned that the Lower Mainland has lost 90% of its wetands and on Cortes you suspect we have probably lost close to 60%. What does this mean in terms of our changing climate?  

MC: “I can talk a little bit about the importance of wetlands in terms of climate change, adaptation and resiliency.” 

“First of all,  wetland soils that stay saturated all or most of the year are carbon sinks generally.  Because the wetlands soils stay wet there’s a lack of oxygen and so there’s a  lack of aerobic breakdown of the plant material. So they sequester and store carbon in the wetted soils. When those soils are drained, then the oxygen comes into the soil and then the carbon is released into the atmosphere.”

“There is a lot of initiative from the government going into rewetting drained wetland soils, in terms of looking at a carbon sink potential.”

“The other strategy that’s super important for climate change adaptation and mitigation and resiliency is protecting and conserving mature carbon storing landscapes, like forests. When we have logging roads and failing infrastructure, like ditches or culverts, that are washing out and causing erosion and incision of stream channels, then that has an impact on the forest by lowering the elevation of water that’s stored in those soils.  That in turn, causes the forest to become more vulnerable when we have heat domes or forest fires, for example. They’re more vulnerable to pests, to wind damage and to lack of water.” 

“We’re also seeing increasing intensity and frequency of precipitation events that are causing flooding and damaged infrastructure. Let’s take Abbotsford last year for example, that was all wetland that’s been drained. The stream channel, the rivers have been diked and dammed.  It’s the infrastructure that’s failing, that’s causing the damage to people’s homes and livelihoods. 

“Wherever we can restore wetlands that will, in turn, help us as humans adapt to climate change impacts in the future.”

CC: What have you personally learned on this project? 

Oh, I have learned a lot on this project. It’s been quite a journey for me. When I first met Tom Biebighauser in 2019, I knew pretty much nothing about wetlands. I was really into landscape design, permaculture design, and ecological landscaping and had been wanting to know more about water and hydrology – because it’s so important to everything.

“For me, this project really initiated a whole new life path where I am now working as a wetland restoration professional.  I don’t even know if I could list all of the things that I’ve learned. It’s just opened up a whole new perspective on life and on wetlands.”

CC: What’s next for Miranda Cross? 

MC: “More of the same, more wetland projects.  I’m working with another company now, and we’re doing wetland and stream restoration projects around the province.” 

CC: If funds become available, what should be the next step for Dillon Creek? 

MC: “We need to take an in-depth look at the historic modifications upstream. When Linnaea Farm’s fields were created, the stream channel was moved to the side of the valley. It was ditched, straightened and turned in a couple of places. Some detailed design work to figure out what needs to be done would be the next step. That would be my recommendation.” 

Links of Interest

Top photo credit: The wetlands one icy winter morning – Photo by Miranda Cross

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