Assessment of Potential Failure Modes for the Truckee Canal at Fernley, Nevada

At approximately 4:00 AM on January 5, 2008, the downhill embankment of the Truckee Canal failed at approximate canal station 714+00, releasing water into the town of Fernley, Nevada. Approximately five hundred and ninety homes were flooded. The canal drained through the breach from both the upstream and downstream directions. Reportedly, water flowed through the breach for up to 9 hours and water depths of up to 8 feet occurred in some locations in the town of Fernley, with water depths of 1 to 4 feet common throughout housing developments in the town. No fatalities occurred as a result of the flooding. Damages were estimated to be approximately $50,000,000. Prior to January 4, 2008, the Truckee Carson Irrigation District (TCID) had been diverting water through the canal at an approximate average daily rate of 370 cfs. A storm event in the Reno/Sparks area on January 4, 2008 generated 1.91 inches of precipitation, which resulted in significant increases in the Truckee River flows and diversions into the Truckee Canal. Based on data from a USGS gauging station about 4 miles upstream of the breach site, it is estimated that the flow in the canal was approximately 750 cfs at the time the breach occurred. This paper includes discussion of: 1) technical information pertinent to the failure, 2) investigations of the canal and breach site, 3) the potential failure modes to help explain the cause of the failure, 4) details of the breach repair. 12 pp., 4 references.