A Koker is a traditional Dutch water management structure, primarily used to control water levels in low-lying areas. It functions as a sluice gate, allowing water to flow in and out of canals, rivers, or lakes. This helps prevent flooding and maintains the balance of water in agricultural fields and urban areas. Kokers are often found in regions like the Netherlands, where land is below sea level. They are essential for managing the intricate system of dikes, canals, and pumps that protect the land from the sea and ensure proper drainage.