Lower than average snow packs and lake levels could lead to a bumper crop of Eurasian milfoil in Shuswap Lake this summer.
The Columbia Shuswap Regional District board received an overview of annual reports from the regional district’s milfoil control program, courtesy of environmental services co-ordinator Hamish Kassa at their June 20 meeting. Kassa said the program’s main goal is to reduce impacts on recreation and biodiversity caused by the invasive aquatic plant.
Kassa said an increased nuisance from the plants is expected this year as a lower-than-average snowpack has led to lower lake levels that could allow more sunlight to reach the milfoil. 2018 saw a relatively small amount of milfoil removed with 33.5 tonnes coming out of the lake. This was only a fraction of the 2016 harvest which totalled 164.5 tonnes.
Kassa said if need be, the program can scale up their harvesting efforts to seven days a week. He likened it to budgeting for snow removal, as the milfoil’s growth rate is dependent on unpredictable environmental factors like available sunlight, nutrient uptake and water chemistry.
Kassa said that while the goal of eradicating the stubborn milfoil is not achievable it can be controlled. He explained the entire Shuswap system is infested with the weeds and they are likely here to stay but through management, their prevalence can be greatly reduced. With the right mix of soil and other conditions, Kassa said a 90 per cent reduction in the size of weed beds is achievable.
Mayor Terry Rysz asked Kassa if the milfoil is prevalent in the Sicamous channel and what effect dredging the channel would have on its prevalence. Kassa said the channel is one of their top priority sites and milfoil has been well-established there since 1979. He said if they were to stop treating the channel, which runs between Shuswap and Mara Lakes, its navigability by boats would quickly decline. He added that a buildup of silt does add to the problem.
Along with their control work in the milfoil-infested Shuswap Lake system, Kassa spoke of the monitoring work they do on other lakes in the area.
CSRD Electoral Area F director Rene Talbot asked specifically about monitoring at high-altitude lakes such as Spa, Arthur and Boolean Lakes, which are clustered just north of Falkland. Kassa said they monitor most lakes that have boat launches since milfoil most often spreads on boats.
According to the 2018 milfoil program report, Joyce Lake, Gardom Lake and the portion of Adams Lake which is within the CSRD boundary were surveyed for milfoil between September and December 2018. The surveys found no milfoil.