City Park submerged in worst-case scenario
100s of properties could be flooded if Okanagan Lake reaches maximum level, city warns
The feasibility of increasing the drainage capacity of Okanagan Lake should be examined once the current flood risk passes, says Kelowna Mayor Colin Basran.
The 60-year-old drainage system can lower the level of the lake by 11 centimetres a week, a rate that isn’t sufficient to avert the prospect of serious flooding in the next 10 days along many areas of the city’s shoreline.
All of City Park could be under water, to varying depths, with flooding also affecting hundreds of other public and private properties if the lake reaches its new predicted maximum of 343.5 metres above sea level, officials said at a Monday news conference.
“It’s pretty scary,” Basran said after the news conference. “But we’re pretty fortunate so far that the protection that’s put in place is doing its job.”
Peak water is forecast to occur around June 17 as one-third of the mountain snowpack has yet to melt, though the actual date and precise maximum level are subject to variables such as temperature and rainfall, officials say.
“It all depends on if it rains hard, or if it’s hotter than predicted,” city manager Ron Mattiussi said. “It’s not an exact science.”
The lake was at an elevation of 343.24 metres above sea level on Monday, already a historic high point, and flood defences were being reinforced at several locations along the shoreline.
Hot weather today and Wednesday, with temperatures around 30 C, is expected to quicken the snowmelt and increase the flow of Mission Creek, which carries one-third of all water that enters Okanagan Lake. In addition to 200,000 sandbags added to the local supply on Monday, another 250,000 are expected today, officials say.
Dramatic, newly prepared flood zone maps for the downtown show water reaching from the lake to cover all of City Park, most of Stuart Park, all of Manhattan Point and the north half of the Prospera Place arena property.
The Delta Grand hotel could become encircled with water, with the flood crossing Water Street and extending east up Clement Avenue almost to Richter Street. The hotel buildings, however, are shown as being outside the flood zone.
It is not possible to predict the depth to which the area would be flooded, Mattiussi said, explaining that would depend on local topography and water levels would vary “area by area.”
South of the William R. Bennett Bridge, many neighbourhoods along Abbott Street are within the flood zone, as are parts of the West Kelowna shoreline and areas along Beach Avenue in Peachland.
Officials stressed the map projections were something of a worstcase scenario, though they advised property owners in the expanded flood zone to redouble efforts to sandbag their yards and homes.
Flood defences along the mouth of Mill Creek and Mission Creek were being enhanced, as were waterfront areas near Kelowna General Hospital.
After the press conference, Basran was asked if he would raise questions with the Ministry of Environment about the ability of the lake’s drainage system to be expanded, particularly a key control point at the Penticton dam where water can currently be released at a maximum rate of about 70 cubic metres per second.
“I think those will be conversations that we need to have, but not from a position of trying to point blame,” Basran said. “Climate change is real, and I think we’re going to see weather events like this a lot more frequently. We’re going to have to talk about what needs to be done to address what is becoming the new normal.”