TWAIN HARTE - CA00649-2160
Dam Name: TWAIN HARTE
State: CA
Downstream Hazard Potential: S
Incident Type: Non-Failure
Incident Date: 08/03/2014
Incident Driver: Unknown
Incident Mechanism 1: Under Investigation
Incident Mechanism 2
Incident Mechanism 3
Incident IDCA00649-2160
Incident DescriptionThe dam was built on solid granite. Very hard solid rock. On 8/3 the massive right abutment rock, exfoliated. This created a new seepage path which resulted in 50 gpm additional seepage. Previous to this there was only wet spots and no active seepage.
Named Hydrologic Event
EAP Enacted (Y/N) due to Incident
Fatalities (Number)
Number of People Evacuated
Number of Habitable Structures Evacuated
Number of Habitable Structures Flooded0
Other Infrastructure Impacts
Economic Damages (in $)
Response
Volume released at failure (ac-ft)
Additional Remarks or UpdatesWe immediately drew down the reservoir to make a detailed inspection and as a precautionary measure. The situation is now stable and no dam safety threat. We will complete detailed analysis of the dam and abutment to figure out next steps. I think we will conclude the dam wasn¿t in danger, but we will see.
Owner TypeP
Dam TypeMV
Primary Purpose(s)RS
EAPNR
Dam Height36 ft
Max Storage (ac-ft)143.00
Surface Area (acres)12.00
Year Completed1928
NID NumberCA00649
River NameTR SULLIVAN CR
Latitude38.0291
Longitude-120.244
Year Modified
Regulatory Agency(ies)Division of Safety of Dams
Incident Time
Incident Duration
Incident Report Produced
Information Sources
