All the quantitative aspects of water management are considered under the name of water quantity.
Desiccation (disturbance of the water volume and cycle of the groundwater layers) and flooding (disruption of the water volume of the watercourse system) may be the result of natural phenomena:
- climate change,
- formation of the landscape,
but they may also be due to human activities that influence the water cycle by reducing:
- the infiltration of precipitation into the soil (e.g. as a result of the expansion of the hardened surface and agricultural exploitation),
- storing the surface water (e.g. straightening the watercourses and the disappearance of natural flood plains),
- storing groundwater and percolation (e.g. as a result of groundwater exploitation and drainage).