Kelowna, B.C. – After a cold winter and wet spring in the Okanagan, the Okanagan Basin Water Board (OBWB) is getting ready for a significant bloom of invasive milfoil in valley lakes this summer.
“In a normal year, spring runoff will bring extra nutrients into our lakes, fertilizing the milfoil just as it’s starting to grow,” explains James Littley, OBWB Operations and Grants Manager. “This year, with unprecedented floods and a predicted hot summer, we’re expecting significant growth with weather that has created ideal conditions for the milfoil.”
But floods and hot weather are not the only reason for the expected increased growth. This past winter, frozen lakes prevented the milfoil rototillers from getting in and uprooting the weed in several locations. Derooting is considered the most effective control method because the weeds are dormant and won’t re-root. “The lakes just stayed frozen longer than we’ve seen in several years, meaning we couldn’t go in and remove the plants,” said Littley.
Lake levels and debris could also affect the milfoil control program this year. As the lake levels drop, weeds that were submerged may suddenly become very visible, forming dense mats on the surface of the water. Boaters are asked to stay away from these mats, as breaking off plant fragments can spread the weeds to new locations, and create a mess on the shoreline. Debris from the flooding also poses a risk to milfoil control machines this summer. The front of the machine has teeth that cut the weeds and place them onto a conveyor belt for collection. Floating logs and other debris can do significant damage to the machines, increasing the time needed for maintenance and repairs.