overstroom

Overstroom is a Dutch term describing water spilling over the banks of rivers, canals, lakes, or other bodies of water. It denotes both the moment of overflow and the resulting flood, and is related to overstroming. The word combines over- (beyond) with stroom (flow). In hydrology and water management, overstroom can refer to natural overflow or controlled releases through spillways to prevent greater damage downstream.

Overstroom occurs when inflows exceed a water body's capacity to contain them. Key drivers include prolonged heavy rainfall, rapid snowmelt, saturated soils, high tides or storm surges, dam or weir releases, and inadequate drainage. Local topography and land use shape where overflow occurs.

Consequences range from temporary inundation of land and transport routes to property damage and utility disruption. Overflow can also trigger erosion, sediment transport, and contamination of water supplies, especially when it flows through urban or industrial areas.

Mitigation combines forecasting and monitoring with physical defenses such as dikes, spillways, and retention basins, plus urban drainage improvements. Land-use planning, floodplain zoning, and green infrastructure help reduce runoff and exposure to overstroom.

In the Netherlands and other Dutch-speaking regions, overstroom is a common term in flood risk management and river-basin planning.