BONASA BREAKS RANCH DAM - WA00000-3156


Incident ID WA00000-3156
Dam Name BONASA BREAKS RANCH DAM
Downstream Hazard Potential S
State WA
Incident Date 04/13/2017
Incident Type Failure
Incident Driver Hydrologic/flooding
Incident Mechanism 1 Insufficient Spillway Capacity
Incident Mechanism 2 Overtopping
Incident Mechanism 3
Incident Description An unpermitted dam impounding 36 acre-feet of water suddenly breached, releasing about 29 acre-feet of water. The resulting flood caused extensive damage to public infrastructure, private property, and critical stream habitat. No lives were lost.
Named Hydrologic Event
EAP Enacted (Y/N) due to Incident No
Fatalities (Number) 0
Number of People Evacuated 0
Number of Habitable Structures Evacuated 0
Number of Habitable Structures Flooded 1
Other Infrastructure Impacts Roads, Bridges
Economic Damages (in $) $10 million to $25 million
Volume released at failure (ac-ft) 29 ac-ft
Response
Additional Remarks or Updates Owner cost for penalties, dam stabilization and downstream repairs added up to about $3M.
Incident Time
Incident Duration 1 hour
Incident Report Produced Yes
Information Sources
Owner Type P
Dam Type RE
Primary Purpose(s) R
EAP N
Year Completed 1960
Year Modified 0
Dam Height 19 ft
Max Storage (ac-ft) 36 ac-ft
Surface Area (acres) 4 acres
River Name RATTLESNAKE CREEK - TR
Latitude 46.0947
Longitude -117.189
Regulatory Agency(ies)
NID Number WA00000
Attachments