|DIVERSION SYSTEMS ON A LARGE SCALE AND USE OF FLOODS
Definition characters description and diffusion
These structures are designed to divert flood flows partially through a channel other than the main course of the wadis in order to benefit additional areas from the detention site through dispersion of floodwater. This technology is found in the very ancient human settlements in the Middle East and West Asia.
General characters description and diffusion
Diversion structures may be led to large individual community ponds or dams for longer-term storage, a practice that is common throughout the drylands of sub-Saharan Africa. Some extraordinary devices found mostly in the arid regions of the Beluchistan, called gabarband, are older than the civilisation of Harappa in eastern Pakistan. The gabarband are stone structures over one metre in length similar to dams. The latter are made of a series of about 60-120 centimetre-high platforms overlapping each other in steps up to the top. In the past, the gabarband were probably used for controlling the floods and alluvium coming down the hills. In fact, they are diversion dams similar to those still in use in the Hadramaut Valley in Yemen.
Advantages and sustainability
These methods allow for the dispersion and therefore control of flood waters as well as for more long-term storage methods for water.