Limans were built in order to fight desertification without depleting groundwater resources, which are becoming increasingly rare in arid ecosystems. Remaining soil humidity can be found in dry river beds (wadis) after rains occur, but these wadis are prone to flash floods. The result is massive soil erosion and the destruction of infrastructure. Also, the infiltration is insufficient because of the water's velocity, even though the runoff would be able to allow for the growth of trees in appropriate places. The aim of building limans is to stop flash floods and to increase water infiltration, thus sustaining the growth of drought-hardy tree species and vegetation underneath them.