The State of Washington and residents in Okanogan County are concerned that more small dams could be at risk of failing after three of them burst in a thunderstorm event last week near Twisp in northcentral Washington.
The tallest dam that went last week was 35 feet high. The longest was 400 feet across. These small public and private reservoirs are mainly for irrigation water for the lush canyon farms below.
Last Thursday’s storm dropped only a couple of inches of rain in that area. But the amount of water running down barren hillsides and funneling into several canyons dwarfed the water let go from the failed dams.
State dam experts have been pulling long hours to shore up two, much-larger remaining dams near the ones that failed.
And there could be more problems to come. In wildfire-struck Okanogan County 45 small dams hold back more than 3 million gallons of water. If they were to fail in another storm it could threaten lives, farms -- and the irrigation systems they depend on.