Information about dam inspections
Construction inspections help verify that field conditions are compatible with the dam's design. These inspections also help ensure that work is consistent with the approved plans, specifications, and construction inspection plan. Our emphasis is on observing and documenting the construction of elements that are critical to the safe performance of the dam. The frequency of our site inspections depends on the size and complexity of the project.
Owner-conducted annual inspections
Owners are required to conduct annual inspections and submit a copy of their inspection checklist to us within 30 days following the inspection. Information to assist owners in performing these inspections can be found in the Part III - An Owner's Guidance Manual. Copies of inspection records must be provided to us upon request.
Typical inspection elements include:
- Condition of the dam crest, and upstream and downstream dam faces — with particular attention to settlement, cracking, slumps, or other distress.
- Condition of the outlet works and spillways noting any erosion damage.
- Testing of infrequently used valves, control works, and other hydraulic mechanisms.
- Observation and measurement of seepage, noting location and concurrent reservoir water level.
- Observation and recording of any conditions that differ from previous inspections.
Periodic inspections are conducted on existing "significant hazard" or "high hazard" dams — those located in areas where dam failure poses a risk for loss of life. The inspections are intended to identify deficiencies and to reasonably assure safe operation and confirm that maintenance is being adequately performed.
Our dam safety engineers perform these inspections every five years. The inspections involve:
- Review and analysis of available data on the design, construction, operation, and maintenance of the dam and its appurtenances.
- Visual inspection of the dam and its appurtenances.
- Evaluation of the safety of the dam and its appurtenances, which may include assessment of the hydrologic and hydraulic capabilities, structural stabilities, seismic stabilities, and any other condition which could constitute a hazard to the integrity of the structure.
- Evaluation of the downstream hazard classification; evaluation of the operation, maintenance, and inspection procedures employed by the owner and/or operator.
- Review of the emergency action plan for the dam including review and/or update of dam breach inundation maps.
Afterward, we prepare a comprehensive report, which includes findings from the inspection and any remedial work needed.
Note: "significant hazard" dams are inspected every five years based on a proviso in the 2009 budget passed by the Legislature. They were previously inspected on a 10-year cycle.
We may perform non-routine inspections of any dam separate from the periodic inspection program. We have identified hundreds of dams that aren't listed in our dam inventory. These inspections continue as staff capacity and funding allow.
Inspection at public request
We may inspect a dam if we receive a request by a dam owner, or if we receive a complaint or request from the public.