Flood Events Likely to Increase

By 250 News

Prince George, B.C. - The Nechako River will likely have higher flows than normal for the next 15 to 20 years regardless of how much water Alcan (RioTinto) dumps into the system.

Forest Practices Board Chair, Bruce Fraser, says there are several things at play when it comes to the flows.  The most important being the impact of the mountain pine beetle. “Live trees capture some of the snowfall in their branches, preventing some snow from hitting the ground, they also offer shade so the  snow that is on the ground melts at a slower pace,  and they absorb a lot of ground water.”

When those trees are dead, they no longer perform those functions, and that means the flows in streams and lakes that feed the Nechako will be higher than normal.  Fraser says   we can expect flows that are 60% higher than normal, and depending on the level of harvesting of the dead trees, that flow increase can climb to as high at 90%.

“It’s a catch 22 situation” says Fraser “If you don’t salvage the trees, the recovery rate for hydrology will be slower, and if you salvage and replant you are looking at 15 – 20 years for the hydrology to recover.” That means 15 – 20 years of increased water flows.

Fraser says when it comes to the level of flow increase, there are several variables including the slope conditions “There is no one answer for all terrain, but the flow increase will be at least 60%.”

The increase flows means an increased incidence of flood events.

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