Water resources : collection of water, dams, water reservoirs
collection of water and especially its storage at the different stages of its course means that different types of works are necessary.
This storage might be for the production of power, irrigation, the supply of water to towns, protection against flooding or for the requirements of river navigation as well as nautical leisure pursuits.
Water intakes are usually quite simple, often a valve regulating access to an evacuation pipe in the body of the retaining dam and sometimes works which are not part of the dam having a weir at the entrance channel of the pipework.
Dams, which are single-use or more often multiple-use, are very different in nature, size and design:
- dams «along rivers» in order to regulate the rate and height of water of the stretch of water,
- storage dams through a gorge or a valley, storing large quantities of water for the production of power, irrigation, regulation of canals or supply to towns,
- gravity dams, built in earth and rock for large valleys,
- arch dams, constructed in concrete, leaning against the walls of the rocky gorges where these are narrow.
There are many different kinds of dam, from simple storage or surge tanks to split the regularity of supply from the irregularity of distribution, or even to facilitate the evacuation of high rates of flow due to unusual rain conditions.
They can be underground or above ground in order to supply water to taps with sufficient pressure and to better control irregularity of usage.
In France these water reservoirs are usually constructed in concrete, whilst in the United States steel constructions dominate.