干旱区生态环境知识资源中心

The soil erosion is caused by several factors, such as the climate conditions and the land morphology. In arid or semi-arid lands, this phenomenon is widely spread, because of the appreciate conditions that reinforce the erosion development such as (the lack of vegetation, sand, wind and seasonal floods...). Dam Djorf-Torba is located in an arid area; it spreads over a large area of sub-Saharan basin a surface of 22000 km(2) with an initial storage capacity of 350 million m(3). Soil erosion in the dam area causes siltation, which affects negatively on performance (reduction of the storage capacity, blocking the bottom drain and risk of instability of the dam) According to statistics of the National Dam and Transfer Agency (N.D.T.A, 2004), the rate agency silting up of the dam is about 25%, corresponding to an annual loss of 0.75 to 1% capacity clearance from the impoundment in 1969.

Our research works are intended to draw up an erosion distribution map which generates considerable volumes of different nature sediments.