Hydrocoop is a non-profit-making organisation formed to promote international technical cooperation in dam engineering, with special focus on flood control, spillways and sedimentation. It is the outcome of a perceived need for a new approach to the issues described below.
Extract from Hydrocoop website:
I - EXCEPTIONAL CIRCUMSTANCES:
Risk assessment for exceptional circumstances is logically based on the probability and impact of such circumstances.
Ia - Floods
For gated dams an additional risk is overtopping due to gate jamming: the yearly probability of this occurring has been 0.5 or 1 x 10-4: exceptional rains causing large floods may disrupt electric power supply, transmissions, computers, and access, and may cause panic. There are two key points for evaluating this risk: the probability of the flood overtopping the dam when all the gates are closed, and the quality of maintenance, training of operators, and emergency measures: practical guidelines on how to reduce this risk have been given by a freely available report published in 1998 by the French Committee on Large Dams and based upon the operation of five hundred dams and related incidents.
Gate operation (or failure) may cause sudden flow increases which may possibly be dangerous, even for rather small flows.
For more information please refer to Hydrocoop webiste http://www.hydrocoop.org/rsmwhatsort2.htm