While the flood risk across the Thompson-Okanagan region is not as threatening as it was two weeks ago, weather conditions can still play havoc with that optimistic outlook.
Dave Campbell, head of the B.C. River Forecast Centre, says of the three elements impacting the flood assessment—high elevation snowpack, extreme hot temperatures and rainfall—precipitation remains the largest concern as the snowmelt runoff begins to dissipate.
Campbell said the Kootenays and the Thompson watershed are isolated flood concern areas probably over the next seven to 10 days window.
Okanagan Lake currently sits at 342.6 centimetres, which is 12 cms higher than full pool but, so far, that has not caused serious flooding issues. In the Shuswap Lake area, what continues to be monitored closely is the tributaries such as the Salmon River sending winter freshet into the lakes system.
“As the snowmelt is absorbed, that source of water feeding the tributaries feeding into places like Okanagan Lake begin to run out of gas, but the risk is still threatening because of the impact of rainfall,” Campbell cautioned.
“It looks pretty dry in the forecast through the end of this month but June is typically the rainy season for the B.C. Interior s what impact that might have remains to be seen.”
Sean Reimer, section head of public safety and protection for the B.C. Ministry of Forests, Lands, Natural Resource Operations and Rural Development, said he still stands behind is pre-spring prediction of Okanagan Lake hitting the 343 cm mark.
Reimer said the Okanagan Dam lake volume release in Penticton is at 54 cubic metres per second, which could be pushed to 60 or higher over the next two weeks.
“We are capable of pushing that release boundary up to 78 which we did on two occasions last year. However, there are substantial problems downstream with erosion and damage to the channel all the way to Oliver if we go to that extreme,” Reimer said.
“But there is more room for flow as the Okanagan River begins to see a drop off in tributary flows into that river. But it really depends on weather conditions. If we get a lot of rain in the next week or two, and the tributaries start to rise again, we may have to back off the lake release flows a bit.”
Reimer noted two years of spring high water issues in Okanagan Lake does raise discussions about a feasibility study into increasing the water collection capacity of the South Okanagan watershed from Penticton to Osoyoos.
“That certainly comes up in conversation but no firm plan is in place at the moment. That is a really serious financial undertaking as you don’t just look at increased capacity from Penticton and Skaha Lake, you have to look at increased capacity all the way down to Osoyoos and carrying on to the Columbia River,” Reimer said.
“Nobody has pulled the trigger on anything yet.”
Campbell said the impact on farms and ranches from flooding is worse than last year, but so far the damage to agricultural operations has been isolated.
B.C. Agriculture Minister Lana Popham said dairy farms are the biggest concern, because having to shift operations from one farm to another is disruptive to the productivity of the farm and the cows.
“We have help on stand-bye if those situations arise but it’s something we only want to have to do as a last resort,” Popham said.
Popham indicated ranchers feel less impact because cows will migrate to higher ground, but two dairy farms on Barnston Island in Surrey along the Fraser River have already had to be relocated.
“We are monitoring the situation and making sure the lines of communication are open should flooding issues occur,” Popham said.
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