An overflow spillway is a structure designed to manage excess water in a reservoir or dam. It allows water to flow safely over the top of the dam when the water level rises beyond a certain point, preventing potential flooding or damage to the dam itself. This controlled release helps maintain the stability of the structure and protects surrounding areas. These spillways are often built alongside or integrated into dams, such as those found in hydroelectric power plants or flood control systems. They can be made from various materials, including concrete and earth, and are essential for effective water management in many regions.