MOCCASIN LOWER - CA00122-3257
Incident ID CA00122-3257
Dam Name MOCCASIN LOWER
Downstream Hazard Potential H
State CA
Incident Date 03/22/2018
Incident Type Non-failure
Incident Driver Other
Incident Mechanism 1 Insufficient Spillway Capacity
Incident Mechanism 2 Reservoir Overfilling
Incident Mechanism 3 Spillway Erosion/head Cutting
Incident Description Blockage of Moccasin Creek Bypass Tunnel caused sudden rise of the reservoir above core wall to nearly the dam crest because of insufficient spillway capacity. More in Remarks.
Named Hydrologic Event
EAP Enacted (Y/N) due to Incident Yes
Fatalities (Number) 0
Number of People Evacuated 20
Number of Habitable Structures Evacuated 1
Number of Habitable Structures Flooded 1
Other Infrastructure Impacts Water/sewer lines
Economic Damages (in $) $25 million to $50 million
Volume released at failure (ac-ft)
Response Immediate response by dam owner, Division of Safety of Dams, and first responders.
Additional Remarks or Updates Fish Hachery immediately downstream was evacuated - likely less than 20 people
Incident Time
Incident Duration 2 days
Incident Report Produced Yes
Information Sources CA DSOD
Owner Type L
Dam Type RE
Primary Purpose(s) HOS
EAP Y
Year Completed 1930
Year Modified 0
Dam Height 60 ft
Max Storage (ac-ft) 554 ac-ft
Surface Area (acres) 29 acres
River Name MOCCASIN CREEK
Latitude 37.8123
Longitude -120.306
Regulatory Agency(ies) DWR, SAFETY OF DAMS
NID Number CA00122
Attachments
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