Water depth is the underwater depth of the floor of water bodies, such as lakes and rivers. In other terms, it is the relief map of underwater land.
Water depth is an important variable when studying water ecosystems as it impacts the amount of sunlight reaching the floor of water bodies, affecting both plant life and fauna life. Indeed, as the depth increases the amount of sunlight decreases, leading to a reduction of vegetation growth. Vegetation, and mainly phytoplankton, is responsible for oxygen production and is the first level of the whole life chain. As a consequence, depth is of major interest for various fields such as ecology, fish production, etc.
Depth of water bodies can be estimated through field/ship campaigns but estimation lake and river depth using satellite sensors is still challenging.