Abstract:
For the purpose of controlled release of water from the dams spillway is provided. Spillway releases floods so that the water does not overtop and damage the dam. Except during the flood periods water generally does not flow over the crest of the spillway. Devices such as Floodgates and Fuseplugs are constructed along with the spillways to regulate the flow of water and dam height. A controlled spillway is the one which is provided with mechanical structures such as gates in order to regulate the flow. On the other hand, uncontrolled spillways does not possess any gates, when the level of water rises above the crest level of the spillway it begins to be released from the reservoir of the dam. The nappe depth above the dam’s crest governs the rate of discharge. It’s a well known fact that about 20 to 30 % of dam failures are attributed to the failure of spillway gates, which confirms the urgent need of improvement in gate operations in order to enhance dam safety. In some cases due to the failure of the controlling systems, interrupted power supply or some manual mistakes by the operators result in the failure of dams. Fuseplugs and fusegates are collapsible devices which are by nature collapsible devices. Under normal operations they behave as conventional spillways but when catastrophic floods occur, these devices get collapsed or they get toppled about their downstream abutments and give additional space to water to pass through and thus ensuring the safety of dam under catastrophic floods and freak hydrological events.
