National Dam Safety Program. Croghan Dam (North & South) (Inventory Number N.Y. 694), Black River Basin, Lewis County, New York. Phase I Inspection Report,
NEW YORK STATE DEPT OF ENVIRONMENTAL CONSERVATION ALBANY
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A visual inspection of this dam and the engineering analyses performed revealed that there are a number of structural deficiencies on this structure. The structural stability analyses indicate that the factors of safety against both overturning and sliding are less than desireable. When the dam is subjected to severe loading conditions ice load, flood flows, the safety factors fall to critical levels. Further investigation of the stability is needed including subsurface investigations and concrete coring. This information should then be incorporated into a detailed stability evaluation. Appropriate modifications to the dam should then be made. It is recommended that within 6 months of the date of notification of the owner these investigations should be commenced, within 18 months, necessary modifications to improve the stability of the structure should be completed. The hydrologichydraulic analysis performed indicates that the spillway does not have sufficient capacity to discharge the peak outflow from one-half the Probable Maximum Flood PMF. However, a high tailwater condition could be expected for this storm event and a dam failure would not significantly increase the hazard to loss of life from that which would exist just before an overtopping induced failure. Therefore, the spillway capacity of this structure has been rated as inadequate.
- Hydrology, Limnology and Potamology
- Civil Engineering