Kelowna beefing up drainage
City renting large pumps to help move stormwater into Okanagan Lake
Stormwater could be pumped rather than drained into Okanagan Lake in the days ahead.
Officials with the City of Kelowna are arranging for the short-term rental of large-capacity pumps from contractors in Vancouver to ensure water gets from downtown drains into the lake.
“We know from experience in the past that when the lake is at a certain level, our gravity-dependent storm system doesn’t discharge fast enough because the lake sort of pushes it back,” utility services manager Kevin Van Vliet said Wednesday.
“So what we do is we actually close the discharge to the lake (along the waterfront) and we pump the stormwater up and across to the lake,” Van Vliet said.
“We’re working on acquiring the pumps from the coast,” he said. “They are large-capacity pumps, 12 inches wide (30.5 centimetres), and we expect to use these pumps soon.”
It’s rare for the city to rent such pumping equipment to deal with high water levels; the last time was in June 2011. Before that, such pumping equipment hadn’t been deployed in 21 years.
Through one week of usage in June 2011, four large pumps had dropped the water table in downtown Kelowna 1.6 metres. Before they were switched on, the water table was just 0.6 metres below the surface.
After six days, the level had dropped back to 2.3 metres underground.
The lake is currently near its socalled target elevation, the maximum level that can be contained without shoreline flooding, of 342.48 metres above sea level.
Current projections, based on factors such as stream flow, weather forecast and predicted rate of snowmelt, are for the lake to rise as much as 30 centimetres above the target elevation.
Residents near Mill Creek and Mission Creek were urged Wednesday to prepare for likely flooding tomorrow and Saturday (see related story above), but even those living downtown could experience high water levels in their yards and homes, Mayor Colin Basran said.
“If you live near a lake or a creek, get prepared, but also if you live in a low-lying area,” Basran said.
“So if you live in downtown Kelowna and maybe you’ve seen traditionally, over the years, a little bit of water seepage into your basement, that seepage could get a lot worse soon and be at unprecedented levels,” Basran said.
“Move things that are maybe in your basement — keepsakes and mementoes and important possessions. Get them out of your basement,” Basran said. “Plan for the worst-case scenario.”