Local governments in the Okanagan are calling on boaters to be mindful of their wakes in shallow water, for the sake of swimmers, drinking water, wildlife, the shoreline and more.
Power boaters on Kalamalka and Wood lakes are asked to go slow and keep wakes low as they head to the ‘Playzone’, where water is deeper than eight metres.
The call to action comes after the conclusion of a 2019 study, which identified that wakes and prop wash from powerboats could disturb the lake bottom up to a depth of eight metres, creating drinking water problems when contaminants in lake bottom sediment are kicked up by wakes, entering drinking water intakes. These contaminants can include bacteria, heavy metals, pesticide residues and hydrocarbons.
“The contaminants can enter lakes through stormwater run-off. They settle on the lake bottom and are naturally covered by new non-harmful sediment like sand and fine clay particles. However, when the sediment is disturbed and kicked up by boats, those harmful substances are back in transit in the water and can be drawn into water intakes.” said Tricia Brett, water quality manager with the Regional District of North Okanagan.
Water intakes in Kalamalka Lake provide drinking water for approximately 60,000 people and increased contaminants in the raw water can lead to higher water treatment costs, Brett said.
So, how deep should the water be before boats hit higher speeds and bigger wakes?
“Once you’re deeper than eight metres or approximately 25 feet, that’s your best play-zone!” said Heather Larratt, lead researcher of the 2019 study.
“Not only will you help keep drinking water clean, protect habitat and avoid unnecessary erosion of the rail trail, deeper is better for making great waves for sports like wake boarding or water skiing. It’s a win-win.” says Larratt.”
Other boating impacts in shallow water include the disturbance of fish habitats and shoreline bird nesting, as well as shoreline erosion that can affect the Okanagan Rail Trail.
“There are natural factors that cause erosion to the shorelines on the lakes. Storms can generate large waves, but the storms usually travel in a north-south direction and over time, storm waves have created rock and pebble beaches,” said Greg Buchholz, director of infrastructure services for the District of Lake Country.
“Wakes from boats create waves that hit the shore at a much higher frequency and come from many directions which impacts the shorelines in ways that the storms do not.”
Boating in shallow waters at high speeds also increases the risk of injury to swimmers and anyone recreating near the shoreline, officials said.
‘Head to the Playzone!’ is a new campaign effort by the RDNO, the District of Lake Country, the District of Coldstream and the Okanagan Collaborative Conservation Program, with support from the Okanagan Basin Water Board through it’s Water Quality and Conservation Grants.