Hydrology

Property of a porous solid to let water through.

Property of a body, a solid - especially a soil, a rock - to be penetrated and crossed by a fluid, water in particular, under the effect of a potential gradient. A parameter expressing quantitatively this property, with respect to the characteristics of the fluid, water in particular: flow that can pass through a unit section of the solid considered, under the effect of a hydraulic load gradient unit, under determined conditions of pressure and temperature (homogeneous size at a speed, noted K).

Machine capable of producing mechanical energy from water and then converting it into electricity. The turbine is the main component of a hydropower plant.

Flow, or the lowest water level of the year, as measured by the water level or by the flow. During a period of low water, the river only takes a minor bed.

Methodology, based on the study of stream flows, which allows assessing the water inflow that is specific to any section of the river.

  Assessing the amount of water available in a soil, as compared to its optimal reserve (useful reserve). When the soil moisture index (SWI) is close to 1, the soil is wet (greater than 1, the SWI indicates that the soil tends to saturation). Conversely, when it tends to 0, the soil is under water stress (less than 0, it indicates that the soil is very dry).

Branch of fluid mechanics which concerns the motion of fluids, whether liquid or gaseous. Hydrodynamics focuses on the properties of fluids, including velocity, viscosity, density, pressure, and temperature, as a function of space and time.

Stream passing through a very large cavity (e.g. a cave or a cavern) or a set of large communicating cavities.