5.1 Dam Inspections

From my own experience, sometimes engineers or owners overlook importance of very basic, but crucial check for dam safety. Dam inspections are the best solution to prevent too-late unstable condition of dam. Practically, DWR gives an instruction for dam inspections (Richard Baines, DSOD / DWR, 1999).

Regular inspection is simple, but gives us a plenty of symptoms of current dams. The inspecting engineer's eyes are the best instrument for reviewing the current status of a dam and reservoir and his brain is the best computer for analyzing the results. We should remember to look at everything on and around the dam and question anything that is out of the ordinary or changed. Also, it is very important to take lots of notes and photographs and adequately document the findings.

The dam should be judged to be: 1, satisfactory for continued operation; 2, satisfactory for continued operation with some qualifying statement, like being subject to the review of some aspect (i.e., seismic stability); 3, satisfactory as operated at a restricted level; or 4, unsatisfactory. For legal protection to limit liability for what is concluded, it is important not to state that the dam "is" satisfactory but is "judged" safe or satisfactory and to state the basis for the conclusion.

The laws governing dam safety are equal in treatment of all dams, including requiring corrective action. It is the engineer's responsibility to use judgment in assessing the severity of a deficiency, and what time schedule for rectifying the situation is reasonable, taking into account the damage potential. The damage potential is based on the size of the dam and reservoir, the estimated population that would have to be evacuated and the estimated monetary loss to property from a failure. However, should the integrity of the dam be threatened, immediate response is ordered.