With water levels dropping on the Arrow Lakes Reservoir following a hot and dry summer, BC Hydro says it is monitoring the risks to fish.
The annual runoff for this year is expected to be 74 per cent of normal, so the water elevation drop is expected to continue.The lower water levels are in the reservoir, the higher risk there is of fish stranding or blocked tributary access.
"Our biologists are currently on the ground to monitor conditions and assess priority stranding sites," said BC Hydro in an Aug. 30 statement. "Based on the current reservoir forecast as well as the information we learned last year, we expect that the fish stranding risk will be highest through the early fall months as the majority of stranding pools begin to emerge."
BC Hydro plans to deploy crews to assess stranding sites and salvage fish where the work can be done safely and effectively.
"Although some fish stranding is not an uncommon occurrence and can happen in any year, we recognize that the impacts are more significant during unusual conditions like this year’s ongoing drought conditions and seasonally low reservoir levels," said BC Hydro.
As of Aug. 30, water levels in the reservoir were at 429.7 metres and are forecast to reach 423.7 metres (1,390 feet) by the end of September.
Currently, the reservoir is approximately three metres higher than it was at this time last year. During the first week of September 2023, water levels were 426.7 metres.
READ MORE: A summary of 2023 at the Arrow Lakes Reservoir
BC Hydro says it plans to use information gathered during last year’s assessment and salvage efforts to inform a planned response for this year.
This focus will be on priority sites where the stranding risk is the highest and crews can work safely.
Based on last year's observations, BC Hydro expects that the majority of stranded fish will be small or young redside shiner, northern pikeminnow, suckers, and some dace and sculpin, as well as carp and other introduced species.
Last year, fewer than 0.25 per cent of fish that were encountered by crews were salmonids such as kokanee, bull trout, rainbow trout and whitefish.
In 2023 over 530 kilometres of shoreline were assessed to identify pools and focus ground surveys and salvage efforts.
BC Hydro's report on their fish stranding assessment and salvage efforts was submitted to the province and is available on the EcoCat Ecological Reports Catalogue.
Kokanee
Last fall, the province, the Fish and Wildlife Compensation Program and BC Hydro surveyed creek mouths in advance of the spawning migration to assess passage and collect additional water temperature data.
Ground and aerial counts for kokanee from last fall indicate the total escapement in 2023 was the second highest in the last decade and the main tributaries used by kokanee remained accessible.
In some of the smaller tributaries, access was limited by low streamflow, which can occur even in years when the reservoir is high, according to BC Hydro.
The same type of work will take place again with monitoring beginning this week and the first aerial assessment planned for Sept. 4.
The province will also continue to conduct annual monitoring of the kokanee population, including spawner returns and reservoir assessments. Annual reports from the monitoring, including long term kokanee data, are posted on the EcoCat Ecological Reports Catalogue website.
There are several things the public can do to help ensure a successful kokanee spawning season:
• Avoid driving around or through wet, soft mud or vegetated areas of the drawdown zone,
• Leave any sampling equipment undisturbed, such as traps marked with floats that you might see in larger pools,
• Please enjoy watching kokanee spawning from a distance to avoid disturbing them and to maintain stream banks,
• Keep dogs out of creeks where kokanee are spawning.
