waterlevel

Waterlevel, often written as water level or waterlevel, refers to the vertical height of the surface of a body of water relative to a reference datum such as mean sea level or a local vertical datum. It applies to oceans, seas, rivers, lakes, reservoirs, wetlands, and groundwater surfaces, and can describe the surface of water within containers or vessels. Waterlevel is a dynamic quantity influenced by meteorological, hydrological, and geological processes and is a key parameter in water resources management, navigation, and coastal science.

Measurement methods vary by context. A staff gauge provides a direct, marked scale of height. Float-based devices track a buoy or float and transmit a signal to a recorder. Pressure transducers infer depth from hydrostatic pressure. Radar, ultrasonic, or laser sensors measure the distance to the surface. Satellite altimetry can monitor large-scale sea level changes, while tide gauges, buoys, and groundwater piezometers serve specialized needs for coastal, open-water, and subsurface contexts.

Waterlevel informs a wide range of applications, including flood forecasting, dam and reservoir operation, irrigation planning, navigation and dredging, coastal engineering, environmental monitoring, and climate research. Levels can fluctuate with tides, precipitation, runoff, snowmelt, evaporation, groundwater changes, and wind-driven water setup. Atmospheric pressure also affects sea level measurements (the inverse barometer effect). Because datums vary by region, reported waterlevel values are typically referenced to a local or national vertical datum.