2021: Heat dome, Level 4, and a kokanee die-off

2021 is the clearest recent drought and the template for how a modern Okanagan drought propagates through all three lenses at once.

Local government & infrastructure

• The Province declared Okanagan Drought Level 4 (second-highest on the 0-5 scale) on Saturday, August 14, 2021; at Level 4, water licence holders not served by local water utilities were asked to reduce water use by half, and the Province warned regulatory action under the Water Sustainability Act was possible if conservation targets were not met. [High] (source)
• The Okanagan was escalated to Drought Level 3 (severe) in early-to-mid July 2021, with water users asked to reduce consumption and licence holders drawing directly from the large lakes or the Okanagan River channel asked to conserve. [High] (source)
• The City of Kelowna moved its water-utility customers to Stage 1 residential watering restrictions in summer 2021 (effective mid-July, ~July 12) in response to an unprecedented dry spring and hot early summer; this was Kelowna’s first activation of watering restrictions in several years. [Moderate] (source)
• West Kelowna moved to Stage 2 water restrictions on July 20, 2021 due to drought conditions, tightening residential watering rules for its utility customers. [High] (source)
• Okanagan Lake is managed under the provincial Okanagan Lake Regulation System (dam at Penticton) against a provincial-federal agreement that sets 340.4 m as the ‘lowest desirable’ level; in December 2021 the lake sat at 341.51 m, ~35 cm below the prior December, illustrating the drawdown pressures on the regulation system during the drought. [High] (source)

Quality of life

• Record drought and heat forced closure of nearly all Okanagan rivers and streams to recreational angling effective on/about August 11, 2021 through September 15, 2021, covering Management Units 8-1 to 8-15 and 8-21 to 8-23 (Christina Lake, Grand Forks, Osoyoos, Oliver, Penticton, Keremeos, Princeton, Summerland, Peachland, Kelowna, Vernon, Cherryville); lakes stayed open. Many waters recorded 25-30 C, and anglers were advised to avoid waters above 20 C. [High] (source)
• The late-June 2021 heat dome (valley temperatures approaching ~43 C) scorched and scalded Okanagan tree fruit; by June 29, 2021 the provincial production-insurance program had received 31 notices of loss from Okanagan tree-fruit growers (plus 50 from Lower Mainland berry growers), with apples showing sunburned leaves and scalded fruit. [High] (source)
• Kelowna and Vernon recorded their driest spring on record in 2021, and the Okanagan recorded exceptionally low (record-dry) soil moisture as the drought worsened - context for residential watering restrictions and agricultural stress. [Moderate] (source)
• Recreational fishing was banned in many Okanagan rivers and streams because of low flows and high temperatures, though fishing remained allowed in small and large lakes; the closures reduced summer angling/recreation opportunities across the valley. [High] (source)

Environmental flow & fish

• An early-February 2021 drawdown of Okanagan Lake (begun to reduce spring flood risk given an above-normal snowpack) prematurely exposed shoreline kokanee spawning areas; provincial sampling found 75% of kokanee eggs and alevin dead within the ~25-cm vertical drawdown zone. The Okanagan Nation Alliance had warned the government the predicted fry-emergence date was ‘too early,’ and the Province paused the drawdown in early March after impacts became apparent. [High] (source)
• The kokanee egg/fry die-off was especially damaging because it followed a record shore-spawner return in 2020 of ~316,000 fish (214% of the 10-year average, the best return since the 1970s); BCWF (via a Freedom of Information request) and director Jesse Zeman warned the setback to restoration could last ‘years, if not decades.’ [High] (source)
• A field biologist survey summary reported that roughly three-quarters of kokanee spawners’ offspring in the surveyed area were killed by the drawdown, with most kokanee observed still in the (dead) egg stage. [High] (source)
• During the July-August 2021 heat, Okanagan River water temperatures exceeded ~23 C, halting sockeye salmon migration; angling closures were imposed in part to reduce stress and post-release mortality on fish already stressed by low flows and high temperatures. [Moderate] (source)
• By December 2021 Okanagan Lake had fallen to 341.51 m - ~35 cm below the prior December and near the low end of its regulated range - though still ~1.1 m above the 340.4 m lowest-desirable level; government stated it did not expect harm to fish spawning habitat at that level. [High] (source)

Sources: news.gov.bc.ca · globalnews.ca · globalnews.ca · westknews.com · kelownadailycourier.ca · news.gov.bc.ca · countrylifeinbc.com · biv.com · globalnews.ca · bcwf.bc.ca · globalnews.ca · kelownadailycourier.ca