The climate change has highly affected sub-sahelian region in the last decades. The amount of annual rainfall has decresed and dry periods became longer, worstening the living conditions of the inhabitants. Annual rainfall is only concentrated in a short period of the year, named wet season, where many heavy rains occur and cause floods. The intensity of rains doesn't permitt the infiltration of the water, which rapidly flows away, so that paradoxically rainfall is one of the main causes of soil impoverishment and erosion.\\Many small dams were built in Burkina Faso to store water from the wet season to be used in the rest of the year, expecially for irrigation.