March 27, 2017 – Maintaining public safety is paramount at NID. This year’s powerful winter storms with record precipitation, intense high flows, and flooding have triggered heightened awareness across California. NID is sensitive to community concerns over potential infrastructure damage due the intensity of this season’s storms in the Sierras.
Current minimal infrastructure damage poses no risk to community safety, and extensive efforts are underway to avoid any impact to water supply. NID is actively working with regulatory agencies to ensure public safety by combining the District’s expertise with specialists from the Federal Energy Regulatory Commission’s (FERC’s) Division of Dam Safety and Inspection, the Federal Emergency Management Agency, the California Department of Water Resources’ Division of Safety of Dams (DSOD), and the Governor’s Office of Emergency Services.
There is some cosmetic damage to the Rollins Reservoir spillway. The most visible damage to NID’s infrastructure is on the Scott’s Flat spillway. To ensure safety and quick repairs, NID has assigned a team of engineers to complete repairs of the damaged spillway. Regular visual inspections are taking place, and a comprehensive evaluation of the spillway will be completed when the winter flows recede.
The District has a robust dam safety program, which includes regular visual and physical monitoring of NID infrastructure. District surveyors monitor the dams for any movement, and staff regularly measure leakage weirs and take readings from piezometers buried in the dams. All of the monitoring information is consistently reviewed by a full time engineer with specialized expertise in dam related issues. The inspection program will alert staff of potential issues.
NID’s ongoing commitment to infrastructure safety involves participation in annual FERC and DSOD inspections. NID also retains an independent consultant to complete a safety evaluation of all FERC jurisdictional dams every five years. The current five-year evaluation is scheduled to be completed this summer.
NID works to maintain public safety and the uninterrupted delivery of a quality water supply by implementing exceptional reservoir safety programs. NID engineers will implement a repair plan to the Scotts Flat and Rollins spillways when access to the damage is feasible, and will continue to monitor infrastructure with specialists. Preliminary repairs are expected to be completed early this summer.