GROUNDWATER DAMS, GENERAL CHARACTERISTICS AND HISTORICAL DEVELOPMENT

A groundwater dam is any structure that serves to intercept or obstruct groundwater flow through an aquifer, both natural and artificial, and thereby provide storage of water underground. They are a suitable water supply structures for regions like Pakistan where arid and semi-arid climate conditions dominate. They can serve as an alternative solution for conditions where above-ground dams are not suitable or applicable because of complex geological situations, safety hazards, and/or silting up of reservoirs. They cannot be used for recreation, power generation, or as universal method of water supply. By using underground dams for storing water instead of surface dams, many of the aforesaid problems may be overcome. Besides their main purpose of providing groundwater storage, underground dams are a reliable means of preventing saltwater intrusion, which is a vital near shore problem. The disadvantages of groundwater dams include: inadequate reservoir capacities, more expensive operation costs (usually pumping), detailed hydrogeological site investigations, and in situ aquifer testing. Groundwater dams have been constructed in several regions around the world, and are not new engineering structures. Historically, these kinds of structures were constructed in Roman times in Sardinia and around Carthage, in present-day Tunisia. This paper emphasizes the significance of this type of structures and reviews the general characteristics and historical development of groundwater dams.