| Dam Name | Pit No. 5 Diversion |
| Incident Date | 6/6/2011 |
| Country | United States |
| State/Province | California |
| Dam Height (m) | 17.7 |
| Uncontrolled Release of the Reservoir | No |
| Dam Type | Gravity |
| Detailed Dam Type | |
| Incident Type | |
| Incident Description | On June 6, 14;04 hrs PST, Pacific Gas and Electric Company (PG&E) submitted an e-mail notification of an oil release incident at Pit 5 Powerhouse tailrace, part of the Pit No. 3, 4 and 5 Project, FERC Project No. 233-CA in Shasta County, California. The incident occurred on June 6, 2011, at 07:29 hrs. The release of oil was caused by an equipment failure of the bearing oil cooling water coil associated with the No. 3 generating unit. As a result of this equipment failure, PG&E estimates that approximately 10 gallons of lubricating oil (Shell Turbo T 68) was gradually released to the river. The No. 3 generating unit has been taken off-line to prevent additional oil from entering the tailrace. Residual oil that remained in the tailrace area was collected with oil absorbent pads and absorbent perimeter booms. Oil absorbent perimeter booms have also been placed at the Pit 6 Diversion Dam intake structure, several miles downstream from the Pit 5 Powerhouse, to prevent oil from being transported downstream of the Pit 6 Dam. Due to the high flow of the river near the tailrace, very little oil remained in the tailrace area. PG&E is in the process of investigating the shoreline area of Pit 6 Reservoir to determine if and how far oil may have been transported downstream of the powerhouse. |
| High Level Failure Mode | |
| Lessons Learned | |
| Initiating Event | Equipment Failure |
| Initiating Event Description | |
| Structures/Components | |
| Failure Mode Description | |
| Emergency Action Plan Implemented | No |
| Consequences | Consequence Data Unavailable |
| Geographic Coordinates - Decimal Degrees | 40.9927, -121.8691 |
| Normal Reservoir Storage (m3): | |
| Crest Elevation (m) |