||DECREASE OF STREAMS
Definition characters description and diffusion
Along waterways, obstacles of stone and wood to create small usable pockets or to raise the water level are in use until the Paleolithic period.
General characters description and diffusion
The technique of small dams to create reservoirs is widespread. The larger structures are more rare, which are in fact rather ‘diversion damns’ (see). The oldest real and big dam is in Sad el Kafara along the wadi Garawi in Egypt, 35 km south of Cairo. The existing remains show that the dam had to be taller than 15 meters. It was dated back to the period of construction of the great pyramids, about 2500 years BC, and was probably never used because it was destroyed by a flood before it was finished. The inside of the dam was made of earth contained by large blocks of limestone. An older dam, but only 5 meters high, is that of Jawa in northern Jordan. Dams along the Indus River were used by the ancient civilizations of Harappa and Mohenjodaro of the III and II millennium BC.
Advantages and sustainability
The dams would create small reservoirs that could be useful to communities of people with agricultural and other needs.