BONASA BREAKS RANCH DAM - WA00000-3156
Dam Name: BONASA BREAKS RANCH DAM
State: WA
Downstream Hazard Potential: S
Incident Type: Failure
Incident Date: 04/13/2017
Incident Driver: Hydrologic/Flooding
Incident Mechanism 1: Insufficient Spillway Capacity
Incident Mechanism 2Overtopping
Incident Mechanism 3
Incident IDWA00000-3156
Incident DescriptionAn 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 IncidentNo
Fatalities (Number)0
Number of People Evacuated0
Number of Habitable Structures Evacuated0
Number of Habitable Structures Flooded1
Other Infrastructure ImpactsRoads, Bridges
Economic Damages (in $)$10 million to $25 million
Response
Volume released at failure (ac-ft)29
Additional Remarks or UpdatesOwner cost for penalties, dam stabilization and downstream repairs added up to about $3M.
Owner TypeP
Dam TypeRE
Primary Purpose(s)R
EAPN
Dam Height19 ft
Max Storage (ac-ft)36.00
Surface Area (acres)4.00
Year Completed1960
NID NumberWA00000
River NameRATTLESNAKE CREEK - TR
Latitude46.0947
Longitude-117.189
Year Modified
Regulatory Agency(ies)
Incident Time
Incident Duration1 hour
Incident Report ProducedYes
Information Sources
