The crest of the emergency spillway in placed

Concept:Emergency spillways:The spillway crest is the uppermost part of the spillway over which water dischargeDifferent zone of storage of water:Minimum pool level: The minimum pool level is the lowest level up to which the water is withdrawn from the RESERVOIR under ordinary conditions.Dead Storage: The volume of water held below the minimum pool level is called dead storage.Full Reservoir Level (FRL): The FRL is the highest water level to which the water surface will rise during the normal operating conditions.Maximum Water Level (MWL): The MWL is the maximum level to which the water surface will rise when the DESIGN flood passes over the spillway.Normal Pool Level: For a reservoir with a fixed overflow it is a maximum water level to which water may rise under normal conditions.The essential requirement of spillway:1. It must have sufficient capacity2. Must be hydraulically & structurally adequate3. Must be so located that it provides safe disposal of water.4. A spillway is a waterway provided in a dam for carrying the SURPLUS floodwater from a reservoir SAFELY to a downstream river.Hence spillway crest is located at normal pool level.