afvoergat

An afvoergat is a controlled opening in a water management structure that allows water to flow from an area of higher water level to a downstream watercourse or drainage channel. It is used to regulate drainage and water levels in polder systems, reservoirs, and urban drainage networks, and forms part of flood defense infrastructure in the Netherlands and other low-lying regions.

Typically, an afvoergat consists of a gate or set of gates that can be opened and closed to control outflow. Gate types include hinged, sliding, or radial gates, operated by hydraulic cylinders, electric motors, or manual mechanisms. Its operation is often automated, using water level sensors, rain gauges, and control systems to maintain target water levels and prevent backflow. In many installations, the afvoergat works in conjunction with pumps, sluices, and weirs.

Placement is usually in a dyke, levee, or drainage channel and is designed to withstand sustained high flows and sedimentation. Maintenance involves debris removal, lubrication, corrosion protection, and inspection of seals and actuators to ensure reliable operation.

Design and operation are governed by national and regional water management authorities and standards. In the Netherlands these systems are part of a broader flood risk management strategy and are integrated with dike safety and polder management.

See also: sluice, weir, gate, pumping station, polder.