Glossaire de A à Z

Elongated and more or less flared depression dug by a stream or a glacier.

Movable device for stopping or leaving free passage to water. For example: gates are used by dams or locks, valves in hydropower plants.

Part of the cost of production which varies with the level of production. For example, the purchase costs of raw materials are variable costs that increase when the volume of activity or production increases.

Space developed between the wastewater treatment plant and the receiving environment of treated wastewater discharges (it is not part of the wastewater treatment plant). The vegetated discharge areas (VDA) are characterised by the use of plants (mostly aquatic but possibly also terrestrial) and their planting close to the treatment plant, in the space remaining after the building of this plant. The VDA is not a wetland as there is no "long presence of natural water". It is also not a grass strip, specific to the mitigation of non-point source pollution (pesticides, fertilisers, sediments, etc.), especially in agriculture.

Large road or rail bridge, usually consisting of several bays and crossing at high elevation a valley.

Fragility and susceptibility when facing a given hazard or a given pressure.

Species whose entry into the category of endangered species is considered likely in the near future in case of persistent factors that are the cause of the threat.