In this case the control valve used is located in a certain place which is often called the floodgate. As we often hear about floods, this sluice also functions as a flood controller to regulate the amount of water flowing into the river. There are several functions of the control valve, both manually and automatically. This valve can manually close or open the flow by human power. But now many control valves are equipped with electric, pneumatic or hydraulic components. In streams with large capacity and high pressure this is commonplace.