ELLEN M. BANNER / THE SEATTLE TIMESSandbags are lined up around the Green River to prepare for potential flooding.
The Army Corps of Engineers has been working hard to make secure adjustments and repairs on the Howard Hanson Dam and good news arrived last Friday...the chances of flooding have been lowered from a 1 in 3 chance to a 1 in 25 chance!
Since January, they've pumped a half a million gallons into the damaged abutment to hold back water during days of heavy rain. This last Thursday, Corps of Engineers Col. Anthony Wright said that it is, indeed, doing it's job. The grout bonded with earthen materials to slow seepage enough that he was able to increase the capacity of the reservoir behind the dam of about 33% to about 50% of its normal capacity.
Therefore, reducing the risk of causing forced flooding in the Auburn valley region to about 1 in 25 with an overall risk of 1 in 33 with the sandbags and other security features to be installed.
Col. Wright maintains, however, that if we again experience Pineapple Express (a series of storms carrying heavy moisture from the subtropics) like we did in January, he would have to cause flooding by releasing water from the dam.
The new numbers are are fantastic improvement, but residents are still staying on guard.
King County Executive Kurt Triplett stated "the new percentage sounds great, but the reality is we had just that type of storm event 10 months ago. I'm definitely going to be sleeping easier..., but we're not out of the woods."
When the dam is fully restored with a concrete wall built within the abutment, there will only be a 1 in 140 chance of flooding. This could be 3 to 5 years away.
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