Monday, March 27, 2017

Oroville Dam Crisis: Potential Emergency Spillway Breach (February 2017) - Part II

Emergency spillway (also known as auxiliary spillway) length: ~1,700 ft.
Emergency spillway height (till rock rim): ~30 ft, which is mostly likely the breach height according to Mr. Mike Smith, a spokesman for the California Department of Forestry and Fire Protection, and confirmed with UC Berkley Civil Engineering Professor Dr.  Nicholas Sitar. The Oroville Dam itself is safe and will not fail during this event.
Surface area of this reservoir is: 15,805 acres
Volume of the Lake Oroville lost during this emergency spillway breach: 30 ft x 15,805 ac = 474,150 ac-ft
Dam breach peak discharge and duration is computed by Froehlich (2008) equation, developed by Dam Safety Division, Bureau of Reclamation, at Fort Collins, Colorado.
Average Breach Width: 803 ft
Breach Formation Time: 14.82 hours
Predicted Peak Discharge: 251,490 cubic feet per second (cfs), which is almost 20 times the maximum flood discharge through the hydro-electric generators outlet. This dam breach peak discharge is also twice of 100,000 cfs (2,800 m3/s), the peak rate which water flows over Niagara Falls, NY.


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