Drought resilience for Nicola River salmon

Drought is rapidly becoming a serious threat to water security and aquatic ecosystems in British Columbia. Droughts are driven both by climate change and unsustainable land use practices that exacerbate water scarcity. Drought impacts such as low streamflows and high water temperatures pose a serious threat to wild pacific salmon already facing cumulative stressors from habitat loss, climate change, and overexploitation.

Using publicly available hydrometric and water licence data, we conducted an ecological audit of BC’s Water Sustainability Act to determine if current policies were adequately addressing drought in the semi-arid and highly agricultural Nicola basin. Our analysis determined that since the Act came into force, flows in salmon-bearing streams are consistently below the Critical Environmental Flow Threshold—the minimum amount of flow required to support salmon—during the summer spawning season. High water temperatures were also identified as a frequent occurrence. 

Our analysis of provincial water licence data also shows that just three larger users account for over half of all water use in the Nicola basin. Provincial water restrictions intended to protect fish populations during drought have only occurred twice in history, in 2009 and 2015, and were significantly delayed in their implementation. We offer eight policy solutions to improve outcomes for salmon during droughts:

1. Establish a water withdrawal schedule for large users,
2. Legislate a trigger between low streamflows and water restrictions, 
3. Place a moratorium on new water licences,
4. Expand the list of Sensitive Streams under section 17 of the Water Sustainability Act, 
5. Introduce a universal water metering program, 
6. Initiate an immediate review of large water licences, 
7. Develop new ecosystem-based Environmental Flow Needs criteria, 
8. Incentivize a shift away from water-intensive agriculture in drought-prone regions. 

Background

The summer of 2024 is shaping up to be one of the most devastating drought years in history. The province’s snowpack, which is the largest source of water in the summer, is on average 63% of normal levels, with some regions like Vancouver Island 46% of normal. Last summer, low rainfall records were set across the province¹, with many regions recording their driest summers in history. In BC, droughts are expected to get worse as a result of climate change as glaciers retreat, precipitation falls as rain in the winter instead of snow, and summer air temperatures rise. 

The issue

Climate change

British Columbia is experiencing rapidly shifting weather patterns and hydrological regimes as a result of ongoing climate change. A reduction in snowpack, earlier spring melts and warmer summer temperatures will result in increased drought risk across the province. As droughts become more prevalent, conflicts between human freshwater needs and the needs of aquatic ecosystems will also become more frequent. As a result, streams, rivers, and lakes located in historically arid regions of the province, like the Okanagan and Thompson-Nicola, are becoming increasingly water stressed.

Drought

Droughts are fueled both by climate change and land use practices that alter hydrological systems and make watersheds more vulnerable to drier conditions. In the semi-arid interior regions, water diversions for agricultural irrigation are the main land-use driver of drought conditions in the summer²³. Urban sprawl, forestry, and industry also play a role in reducing water availability. 

Drought has a number of serious consequences for aquatic ecosystems and wildlife. Droughts result in low streamflows, which impair salmon spawning activity, reduce juvenile survival, diminish available habitat, and disconnect migration routes⁴. Low streamflows are associated with high water temperature and low dissolved oxygen, which further disrupt the ecological processes that make a stream healthy. Impacts to wild salmon have cascading consequences for the broader ecosystem as well as human communities that are inextricably linked to healthy salmon returns.

Nicola River salmon

The Nicola River is a major tributary of the Thompson River and is part of the Fraser River basin. Located in the semi-arid interior in traditional Nlaka’pamux and Sylix territory, the Nicola watershed is home to several populations of wild Pacific salmon, some of which are listed as threatened or endangered⁵. Drought, and its impacts on river flows and water temperatures, has been identified as a key driver of decline for wild salmon populations in the Nicola. 

Policy context

The Water Sustainability Act is the primary piece of provincial legislation governing the quantity and quality of fresh water in BC Introduced in 2016, the Act includes important provisions for the freshwater needs of aquatic ecosystems. Two key terms in the Act are Environmental Flow Needs (EFN) and Critical Environmental Flow Threshold (CEFT)⁶. These terms acknowledge the impact that water extraction has on streamflows and the health of aquatic ecosystems more broadly.

Conclusion

It is clear that freshwater policy needs to rapidly adapt to respond to worsening climate change and water scarcity. The Nicola watershed is under severe water stress from both climate change and human water withdrawals, with detrimental impacts on struggling salmon populations. Wild, healthy salmon populations are integral to the health of the broader ecosystem and communities that depend on them. As droughts continue to worsen, human water demands and the freshwater needs of aquatic ecosystems are increasingly coming into conflict. This is a scenario that is playing out across the province. It has been 8 years since the enactment of the Water Sustainability Act, which was intended to better balance water demands for human use and ecosystem functioning. Our research echoes the sentiment felt by many water users, scientists, and community members in water-stressed systems across the province;the Water Sustainability Act is falling short on these goals. 

Adapting the Act into a new era of drought will require a paradigm shift in government and society. Freshwater ecosystems can not be treated as an inexhaustible resource for human benefit. Water needs to be valued, protected, and conserved as it is scarce, sensitive, and the foundation of all life.

Appendix

Figure 1. 

Summer (June 1 -Oct 1) streamflows (cubic meters/second) in the Coldwater River, Lower Nicola River, Spius Creek, and the Upper Nicola River between 2016 and 2021. Dashed horizontal line indicates the Critical Environmental Flow Threshold of the stream. Gray shading indicates approximate timing of salmon spawning in the Nicola watershed.

Figure 2.

Proportion of summer days (%) where water temperature in the Coldwater River is above 18ºC, 2003-2022.

Figure 3. 

Streamflows in the Nicola River and Coldwater River during the summers of 2009 and 2015 respectively. Horizontal dashed line indicates the CEFT of the stream. Red shading indicates the duration of the Fish Protection Order (FPO). The 2009 FPO in the Nicola River was intended to protect spawning Kokanee, which spawn in Nicola Lake between mid-August and October. The 2015 FPO in the Coldwater River was intended to protect spawning Chinook salmon, which spawn in the Coldwater River between June and October.

Figure 4.

Total volume (cubic meters per year) of water allocations held by the three largest users compared to all other water licence holders in the Nicola watershed.

1. Dieraurer, JR., Allen DM., Whitfield PH (2021) Climate change impacts on snow and streamflow drought regimes in four ecoregions of British Columbia. Canadian Water Resources Journal 46(4): https://doi.org/10.1080/07011784.2021.1960894
2.  Okanagan Basin Water Board, Water Supply & Demand Project (2019) https://obwb.ca/wsd-index/key-findings/water-use/
3. Nicola Watershed Community Round Table, Nicola Water Use Management Plan (2010) https://www.nwcrt.ca/water-use-management/
4. Fisheries and Oceans Canada, Extreme Environmental Impacts on Pacific Salmon (2023) https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html
5. COSEWIC, List of Wildlife Species Assessed (2022) https://www.canada.ca/en/environment-climate-change/services/species-risk-public-registry/cosewic-list-species-assessed.html
6. Ministry of Water, Land, and Resource Stewardship, Environmental Flow Needs Policy (2016) https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/water-licensing-and-rights/efn_policy_jan-2022_signed.pdf

You can help

Raincoast’s in-house scientists, collaborating graduate students, postdoctoral fellows, and professors make us unique among conservation groups. We work with First Nations, academic institutions, government, and other NGOs to build support and inform decisions that protect aquatic and terrestrial ecosystems, and the wildlife that depend on them. We conduct ethically applied, process-oriented, and hypothesis-driven research that has immediate and relevant utility for conservation deliberations and the collective body of scientific knowledge.

We investigate to understand coastal species and processes. We inform by bringing science to decision-makers and communities. We inspire action to protect wildlife and wildlife habitats.