Final report of the Pacific Fisheries Resource Conservation Council in its role as advisors on wild Pacific salmon and steelhead stocks and habitat.
Backgrounder: Climate Change Adaptation Strategies for the Cowichan River Basin
Submitted by michael on Thu, 10/04/2007 - 09:00
The climate in the Cowichan Basin is influenced by its mountainous geography and the seasonal weather patterns of the west coast. The Basin is home to significant runs of chinook, coho and chum salmon. Chinook returns for 2007 are expected to be very low due to continuing low marine survival, lack of hatchery production and increasingly low summer and early fall flows in the Cowichan River. Changes in precipitation, flows, and temperatures have important influences on salmon in the Cowichan Basin.
Recent years of drought have led to low summer water levels, which in turn have lead to conflicts among users – salmon resources, economic activities, drinking water supplies, water quality, and recreational interests. The Cowichan River is a designated Heritage River and is one of the most important rivers on Vancouver Island for cultural First Nations, recreational, and commercial fisheries. In March 2007, a diverse group of stakeholders collaborated to create the Cowichan Basin Water Management Plan, which offers a good model of how those with seemingly different interests in water can work together to achieve positive results
Water availability during summer months is of greatest concern in the Cowichan watershed for both salmon and people. The river is important for recreation users, such as tubers, kayaking, and canoeing, as well as a source of water for domestic, irrigation and industrial uses. Catalyst Paper is the primary water license holder for Cowichan Lake for its pulp mill operations. Most water for agricultural irrigation and domestic supplies for Duncan and North Cowichan are obtained from groundwater sources. Groundwater use has the potential to directly impact salmon, their habitats, and other water users.
At the moment, human withdrawals from the system greatly exceed inflows during periods of summer low flow. Moreover, water demand to satisfy population growth alone is expected to increase by more than a quarter over the next 25 years. If fisheries collapse as a result of insufficient water, this important source of revenue would be lost to local communities, including the cultural losses and loss of one of the last vestiges of naturally spawning chinook in Lower Georgia Strait. Low water levels can also affect economic benefits drawn from recreation, tourism, and Catalyst Paper mill.
The Cowichan Basin Water Management Plan currently recommends a wide range of soft and hard infrastructure approaches to restructuring water management and coordinating local action. Some key actions are required to help salmon adapt to climate changes.
First, coordinate and implement planning frameworks. The Water Management Plan has developed clear goals, objectives, and actions that work to balance multiple and potentially competing water interests. Next, use demand-side management tools and pricing signals as recommended in the Cowichan Basin Water Management Plan to improve availability of water supplies. This includes installing water meters and volume-based pricing. Water metering can allow individuals, business, and industry to monitor their water consumption and may promote greater personal responsibility for water conservation. Metering also provides data collection that can be used to identify trends in water consumption to formulate local policies that most cost-effectively reduce demand.
Effective operating licenses must be required so that water is not allocated beyond the system’s ability to provide water. Build additional storage capacity and manage water storage to provide flexibility to better optimize decisions over the season and across years. Finally, restore slope stability to help increase egg-to-fry survival. Although not directly affecting water temperature or water flows, actions to minimize these types of more controllable sources of juvenile mortality will be important measures to help offset the additional mortality imposed by climate-induced changes in freshwater habitats.