8/2 Stop 3: Diablo Dam
The Skagit Valley is the 3rd deepest gorge in the United States with 6,500 feet in vertical relief. Only Hells Canyon and Grand Canyon have deeper gorges. During the last major glaciation that peaked 15,000 years ago, a glacier eroded the stream valley into a u-shape. After the glaciers retreated, stream erosion occurred which produced the v-shaped notch at the bottom of the valley. Even though the glaciers retreated after the last ice age, this valley is still affected by glaciers since the Skagit River contains 75% glacial meltwater. The Skagit River and the Diablo Dam reservoir are green due to fine particles of ground up rock (colloids). Colors such as red and blue are absorbed, while green is reflected.
Diablo Dam Reservior
This dam poses a major threat to downstream residents due to faults near the dam. There are "good vibrations" and "bad vibrations." A bad one occurred when the spill gates were open for six hours. The rushing water had matching harmonic frequencies with the rocks below the dam which caused a fault to rupture. When frequencies match, the rock will shatter just as a wine glass does when a singer hits the right note. This fault may have detrimental effects on the Skagit Valley when the next great earthquake occurs, depending on its frequency and intensity.
Fractured rock below Diablo Dam