The Cowichan & Koksilah Watersheds

“The elders talk about salmon runs being so numerous that there were runs all year round and you could fish all year round.”(Tim Kulchyski, Cowichan Tribes Fisheries Consultant)

The Cowichan and Koksilah watersheds, like most in B.C., have changed dramatically in recent decades. Further shifts are anticipated as climate and hydrology change, bringing extremes that surpass existing conditions—already considered a crisis. Climate modeling predicts warmer, wetter winters and longer drier summers for the region.

The extreme droughts and flood events experienced in the past decade are expected to be the ‘new normal’ of the future. If no action is taken, it is likely that in many future years, the Cowichan and Koksilah Rivers will be too dry to support fall salmon returns. See https://www.cvrd.bc.ca/2101/Climate-Change for details and a report on Climate Projections for the Cowichan valley Regional District.

There is evidence that in some areas the aquifers have dropped more than 100 ft. and in others a drop of just 25 ft. has resulted in deep wells going completely dry. As well, the lowest water levels ever recorded were seen on several Ministry of Environment observation wells. These aquifers have dozens of private wells drilled into them, but they are also shared by several water utilities. See https://www.cowichanwatershedboard.ca/content/whats-your-water-worth and https://www2.gov.bc.ca/gov/content/environment/air-land-water/water/groundwater-wells/aquifers/groundwater-observation-well-network/groundwater-level-data-interactive-map.

Salmon Impacts: Salmon are a keystone species in the watershed, providing marine captured nutrients that support the entire ecosystem. Climate change impacts are already resulting in flow reductions that are having serious impacts to all life history stages of Cowichan salmon: interfering with the ability of adult salmon to migrate upstream to spawn; stranding juvenile salmon as they attempt to rear or migrate to the ocean; reducing food and habitat availability; and increasing vulnerability to predation. These impacts are compounded by forestry and land use practices and are expected to increase as climate change progresses. Efforts to mitigate these impacts include controlling water flows with the Cowichan Lake weir, salvaging fry, building more rearing habitat, and trucking salmon upstream in the fall.

Water Supply: Climate change, forestry and increased water demand have affected local water sources, causing wells to run dry in some years. Municipal watering restrictions occur annually. Summer droughts have also reduced surface water availability for agriculture in the Cowichan and Koksilah watersheds, leading to voluntary withdrawal restrictions, and impacts to food production, recreation and tourism. The weir at Lake Cowichan is no longer sufficient to address low summer and fall supplies in the Cowichan.

Winter Flooding: Warmer winters are resulting in reduced “natural storage” in snowpack and increased flooding from Lake Cowichan all the way down to the Cowichan Tribes community near the estuary. Development and land use practices are also contributing to this problem.

Water Quality: Issues in the watershed range from shellfish toxicity in the estuary, to toxic algae in Quamichan Lake, to health risks associated with high E. Coli levels in some areas. See http://www.timescolonist.com/news/local/lower-cowichan-river-closed-to-recreational-use-due-to-bacteria-1.1317360 for one example of high bacterial counts due to low river flows.

Cumulative impacts–Damaged Habitats and Ecosystems: Land use practices have resulted in wide-scale aquatic and riparian habitat degradation throughout the watershed. Existing legislative tools (e.g. Riparian Areas Regulation, Fisheries Act) are not protecting habitats. Local organizations are helping with riparian restoration projects and landowner education, but a comprehensive plan to address cumulative impacts is lacking.

Privately Managed Forest Lands: The majority of the watershed falls within privately managed forest lands, governed by the Private Managed Forest Land Act. As a result, significant resource management responsibilities are in the hands of forest companies. Local and Indigenous governments have limited ability to participate in and influence decision-making for these lands. Although various companies have efforts underway to improve forest practices, concern persists about the impacts of forest operations on the river and watershed. Cowichan Lake Weir: The weir at the outflow of Cowichan Lake has been in operation since 1957. It is licensed and operated by Catalyst Paper and is used to control the outflow from the Lake into the Cowichan River, providing water for both environmental flows and industrial use. With changing weather patterns, decreased snowpack and longer drier summers, the current infrastructure has helped lessen those impacts but is now proving inadequate. For more about this situation, please visit www.weirready.ca

“If the people who live in a watershed are more involved in decision making, better outcomes might be achieved.” (Cowichan Co-Governance Conversations Workshop Participant, 2018).

Related Documents Cowichan Basin Water Management Plan, March 2007 Westland Resources Group

More about the Cowichan Watershed

Ice-Age About 29,000 years ago, precipitation in the form of snow and a cold climate resulted in a period of glaciation that, upon its retreat about 10,000 years ago, formed the deep depression of Cowichan Lake, the much shallower depressions of Somenos Lake and Quamichan Lake, the channels of the Cowichan River and its tributaries, and the gravels, sands, and clays in the Cowichan Estuary.

Plants return As the climate began to warm, plants recolonized the land, watered by winter rain and snow. Up to five metres of water fell yearly on the peaks west of Cowichan Lake. Much of this precipitation would percolate into forest soils, where it would slowly flow into streams and enter aquifers. Annual floods carried soil into the flatter reaches of the Cowichan River, where it accumulated in fertile pockets.

Fish and other Animals Gradually, animals began to fill the ecological niches of the Basin. Salmon came to spawn in the gravels deposited in the Cowichan River. Juvenile fish found excellent rearing habitat in the lakes and channels of the Basin. The web of life in the Basin became complex and resilient.

Aboriginal people reached the Cowichan Valley not long after the glaciers receded. The people adapted themselves to the seasonal pattern of weather, fish, and plants, and a rich culture flourished in the Cowichan Basin for centuries.

In the mid 1800s, Euro-Canadian settlers arrived, bringing a different view of the Cowichan Basin. The new residents made big changes to the hydrologic system in the Basin.

Dykes were constructed to control winter floods that threatened roads, railroads, and settlement. Water was extracted from waterbodies and aquifers to meet increasing human demand. Farmers took advantage of the rich soils in the lower Basin and began to straighten and deepen streams to hasten drainage, drill wells, and extract water for irrigation. With settlements came pavement, storm drains, septic fields, and sewage treatment plants, all affecting water in the Basin.

Industry also needed water, and in the 1950s the government issued a water license to a pulp mill at Crofton to divert substantial volumes of water from the Cowichan River. A weir was built at the outlet of Cowichan Lake to store water for the mill.

In the past 150 years, the face of the Cowichan Basin has changed more than in the preceding 5,000. As the population and development increases in the Basin, so does the rate of change to the hydrologic cycle. Forestry, settlement, agriculture, recreation and tourism, industry, and cultural values compete for water in the Basin, often not leaving enough for healthy ecosystems.

Human impacts The old growth forests are nearly gone and forest soils are thinner, their water-holding capacity reduced. Wishing to be near the water, people build houses on the banks of rivers and lakes, removing riparian vegetation to improve access and views. More than 530 licences have been issued to extract water from streams and lakes in the Basin, and more than 1,300 wells have been drilled to pump water from the aquifers. Thousands of visitors come to the Basin each year to kayak, inner tube, swim, and fish in the lakes and streams and to hike and camp along the shores.

Catalyst Paper continues to withdraw water from Cowichan River for mill operation in Crofton.

Changing precipitation Seasonal fluctuations and unpredictable amounts of annual precipitation create water management challenges in the Basin. The Basin can experience floods in winter and spring and droughts in summer and fall, when water demand is at its peak. In recent dry years, low summer water levels in the Cowichan River system have put fish populations at risk and caused concerns about possible suspension of operations at the Catalyst Paper mill. Droughts also meant falling water levels in the streams and aquifers that supply many people with drinking water, and less water to dilute treated effluent discharges to the River. Water-based recreation, such as boating, swimming, and fishing, has also been affected by low flows in the River. These problems are likely to get worse in the future as climate change alters the hydrologic cycle of the Basin, bringing more intense winter rainstorms, less snowpack and earlier melt, and warmer summers.

A new relationship between people and water needs to be established to ensure that there will be reliable water supplies available for human use, thriving ecosystems, and a healthy economy in the Cowichan Basin, both now and in the future.

The Cowichan Basin Water Management Plan was published in March 2007

On January 28, 2010, the Cowichan Watershed Board was announced.

CWB Website

Targets

Cowichan Watershed