Every year, thousands of salmon return to their natal waters in rivers and streams on the Pacific Coast to spawn. These fish are threatened, at every stage in their life cycle, by predators, climate change, human interference, invasive plant species and more. Despite this, the salmon keep coming back.
Salmon in the S’amunu/Somenos watershed, located in the Cowichan Valley, are particularly at risk, says Somenos Marsh Wildlife Society president Paul Gowland.
“I think we’re on a critical edge with salmon moving [or not moving] into the Somenos watershed,” he says. “I kind of think it could go either way, depending on how things go.”
Water quality in Somenos Lake and the creeks around it is poor – sometimes too poor for salmon to survive. Gravel for salmon to lay their eggs in is picked up and moved further downstream by increasing frequent floods. And fast-spreading invasive plants are making it difficult for salmon to swim past them. More than150 years of intensive land use for agriculture and development, plus extreme weather driven by climate change, have further impacted the S’amunu/Somenos watershed.
A place that once harboured coho and chum salmon now only sees coho, says Gowland, and their numbers are getting smaller.
But, with guidance from Cowichan Tribes, Somenos Marsh Wildlife Society is acting to protect this important watershed. An initiative to restore spawning habitat in Bings Creek is already showing some success.
Land use history and impacts
The S’amunu/Somenos watershed was once known as “the greatest salmon nursery on Southern Vancouver Island,” according to the Somenos Marsh Wildlife Society. Mountain streams converge in the watershed and continue on, through Somenos Creek, to the Quw’utsun Sta’lo’ (Cowichan River) and eventually, the Cowichan Estuary and Salish Sea. Fish, including salmon and trout, and mammals, including elk, bears and cougars, travel through the watershed. It is also home to birds, amphibians and other wildlife.
But over the past 150 years, human use of land in the watershed has degraded water quality and the watershed environment, the wildlife society says. Intensive logging, agricultural development and urbanization each contributed to a less resilient, more polluted ecosystem.
Colonization displaced the Quw’utsun village of S’amuna’, replacing the long rows of longhouses with farmland. Settlers built ditches and dikes to control seasonal water flows, which increased the frequency and severity of floods.
Other industries also made their way into the S’amunu/Somenos watershed. A sawmill, followed by a boat sales business, operated on the marshlands near Somenos Lake until 1988. At that point, parts of the watershed became the Somenos Marsh Wildlife Refuge and, eventually, the S’amunu/Somenos Conservation Area. That area encompasses 200 hectares of sensitive ecosystems, including creeks that eventually flow into the Quw’utsun Sta’lo’ (Cowichan River).
Today, a boardwalk takes vistors through parts of the conservation area overlooking forest, marshland, tall grasses and willow trees that have reclaimed former agricultural land. The conservation area is home to Garry oak meadows and Ye’yumnuts, a sacred ancestral place of Quw’utsun Peoples.
Healthy salmon, healthy ecosystem
Healthy fish are a good indicator of a healthy watershed, Gowland says. Salmon are like the “canary in the coal mine” because of how sensitive the fish are to the environment.
“If you have a healthy fish population, you can be sure that your riparian zones are good and that the water is a good quality,” Gowland says. “If you have those two factors, then other aspects, like the bird and insect populations, are sure to be in good shape as well.”
Salmon spawning grounds are also helpful to other living things. Gravel beds where salmon lay eggs can be home to life at the bottom of a creek, and the fish themselves attract the mammals and birds that consume them, Gowland says.
“We focus on fish because they’re a key part of biodiversity,” Gowland says.
Human impacts on the watershed continue
But past and present human impacts continue to affect water quality and salmon migration.
The Somenos Lake environment is becoming too nutrient-dense, causing something called eutrophication, Gowland says. This increases plant and algae growth and promotes harmful toxic blue-green algae blooms in the summer. The algae growth promotes warmer water temperatures and removes oxygen from it, making the environment hostile to salmon, because they need cooler water and oxygen to survive.
Human activity – such as urban development and farming – contributes to nutrient runoff that enters the watershed, Gowland says. But sediment in the lake is also leeching nutrients that it naturally holds, fostering the growth of algae.
The wildlife society keeps an eye on water quality by taking samples from streams that flow in and out of the lake to measure oxygen levels, dissolved minerals in the water and the pH balance.
“A quarter of the work we do is to do with water quality measurements,” Gowland says. “That tells us from year to year if things are getting better or worse … and we hope to be able to make any improvements, especially in Somenos Creek with oxygen levels there, to help the fish pass through.”
In the last five or six years, an invasive plant has also made its way into the watershed, Gowland says. Parrot’s feather, native to the Amazon River in South America, covers almost 75 per cent of Somenos Creek, which is about three kilometers long. Prized for its beauty, the plant has travelled around the world to decorate ponds and aquariums, and has found its way into many local water systems.
The plant reduces oxygen levels in the water when it grows unchecked, says Gowland. It can also physically block salmon that are trying to swim through the creek with its dense roots and stems.
“Coho seem to be arriving but their numbers coming up into the Somenos system are less than they used to be,” Gowland says. “And that coincides with the arrival of parrot’s feather.”
Flooding from nearby ponds that drain into the watershed, as well as from events like last fall’s atmospheric river, cause surges to make their way through the system. Gowland says these pulses of water can shift sand and gravel, causing large deposits in creeks that disrupt salmon spawning habitat.
Runoff from urban areas enters storm drains and culverts that lead to streams in the watershed, Gowland says.
“So the effect of that has been to change the natural runoff characteristics from a slow increase in runoff when you get heavy rainfall to a really fast increase in runoff because water runs off your roof or off the road very quickly,” Gowland says. “[This] gives you a big pulse of current which causes problems with a displacement of spawning gravel and sand and also causes problems for washing down more branches and logs.”
What can be done for the watershed?
Gowland says that while it can be hard to be optimistic when witnessing the effects of climate change and human impacts on the watershed, all hope isn’t lost.
Somenos Marsh Wildlife Society and other organizations that seek to protect Cowichan Valley watersheds are engaging in efforts to improve water quality and habitat for salmon and, in turn, other wildlife.
The wildlife society is working to increase shade along the creeks to keep the water cool for salmon and deter sun-loving invasive plants like parrot’s feather from spreading, Gowland says. Trees that were once removed to make way for farmland and development are being replanted.
In fact, volunteers from local schools and two workers from Cowichan Tribes just finished planting 1,000 trees along Somenos Creek. While Gowland says there is definitely a need for more trees in the watershed, this is a start.
In 2021, gravel and large rocks were added to small sections of Bings Creek, near the Trans-Canada Highway, to create spaces for salmon to lay their eggs. Salmon have been seen in the area, Gowland says, and he’s “optimistic that they’ll stop there and do some spawning.”
Future plans for wetland restoration in the Averill Creek valley are also underway and the wildlife society is hoping to work with farmers along Richard’s Creek to add shade to the area with riparian planting.More projects, such as invasive species management, fish monitoring, a bird’s nest box program and other riparian restoration, are either underway or being planned. Details can be found online.
How to help
Those looking to get involved and help with projects are more than welcome, Gowland says.
The COVID-19 pandemic had a large impact on volunteer numbers and in-person events, and the Somenos Marsh Wildlife Society hasn’t been able to replenish its volunteers to pre-pandmic levels, Gowland says.
He hopes that as more information is shared about the risks to the watershed and the potential to save it, people will feel encouraged to act and help steward it.
“We’re hoping to get people to come out more and encourage them to publicize what we’re doing,” Gowland says. “If people join or just volunteer with societies like ours – and it doesn’t necessarily have to be our own society – then people will also learn when they come out.”