It has always been a basic need for mankind to secure water resources. The evidence for this is that ruins of open water channels or elevated aqueducts, constructed in ancient times, still exist, and some of them are still in use. In recentyears, notonly have life systems in urban areas been subject to drastic change due to mass consumption, but also agriculturalyindustrial systems.
As a consequence, chronic water insufficiency or draught due to unseasonable weather has become noticeable.
In contrast, the water-preserving faculty of the land is lowered, due to progressive surface covering in urban areas. As a consequence, rivers become susceptible to flooding with a lower intensity of rainfall than ever, resulting in frequent inundation and run-off to urban facilities, as well as making sanitary conditions worse.
Since the source of non-polluted water is located, in most cases, far from the place of water consumption, a facility of water conveyance is necessary. To minimize the fluctuation of water supply amount between the levels of draughtand excess rainfall, a means of storage, in common or temporary use, is required. However, it is often difficult nowadays to construct such facilities as an open water channel or water reservoir on the surface around urban areas, because of the difficulty of site acquisition and environmental restrictions.
An underground solution, on the contrary, will offer the advantages of preventing evaporation and contamination of water, and from secondary pollution of lake or seawater from a reservoir or from the air.
Lesotho Highland Project
Endorsed ITA Papers Overview on survey of water installations underground: underground water-conveyance and storage facilities - Working Group 4 Subsurface Planning
(Tunnelling and Underground Space Technology, Vol. 17, Nr. 2, pp. 163 - 178, 2002)
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