Backgrounder: Climate Change Adaptation Strategies for the Englishman River Basin

Situated on the east coast of Vancouver Island, the Englishman River watershed is rain-driven, with heavy fall and winter rains creating peak flows from October through April, while lower precipitation in the spring coupled with snow melt leads to low summer flow from June to September. The Englishman River is an important contributor to production of all salmonid species, including winter steelhead and coastal cutthroat trout. Chum is the dominant species in the river followed by coho. Steelhead, chinook, pink, and sockeye are also present though in less abundance. Hatchery programs for coho, chinook, and pink are an integral part of fisheries management.

The majority of land within the Englishman watershed is privately owned. Much of the watershed was logged in the early 1900s and again in the 1950s. Agriculture and urban development are the primary land uses, with the largest water licenses allocated for domestic use to the Nanaimo Regional District and the City of Parksville. The economic prosperity and well being of communities within the Englishman watershed is inherently linked to the health of its rivers. In response to declining fish stocks, the government of British Columbia designated the Englishman as a sensitive stream under the Fish Protection Act in 2000. A broad-based recovery plan was developed, has been broadly supported by a diverse group of supporters, and is seen as a good beginning.

Low summer flows in the basin result from low amounts of precipitation during summer months, insufficient storage capacity at Arrowsmith Lake and increased summer demand for water by agricultural, rural and urban users. Habitat declines have been attributed to the extensive channel widening and chronic sedimentation induced by past logging practices. The river rises rapidly in response to rainfall and accelerated snowmelt, falling quickly once a rain event finishes, and the changing climate is increasing the length of low flow periods.

Better water management systems are needed to mitigate against climate-induced conflicts between human and non-human uses in the watershed. A water budget must be developed based on additional flow measurements across the basin to help achieve flow-release targets in the Englishman River, downstream from the Arrowsmith Lake reservoir.

Effective operating licenses should be required to ensure that water is not allocated beyond the watershed’s ability to provide it across all seasons. Compliance with existing water licenses should be assessed because water in some tributaries is mysteriously disappearing and may be due to unauthorized extractions. No new licenses should be issued without appropriate storage to replace withdrawals during the low-flow periods. Water storage must be managed along with continued monitoring and evaluation to ensure that water management is meeting instream needs in the face of competing human demands. Additional storage capacity should be built to provide more water in tributary streams.

Off-channel habitat and stope stability must be restored to mitigate against the expected increases in incidences of winter flood events and adverse effects on survival of juvenile salmon. Streams should be enriched with nutrients, fertilizing streams using salmon carcasses to increase productivity of the system. This can help to mitigate against decreased marine or freshwater survival due to climate-induced changes in these environments.