Small Non-Conventional Irrigation Dams with open and elongated fields.

The objective is to describe the hydraulic infrastructure and social organization in a small system of non-conventional irrigation locally known as presas. The technique consists in controlling runoff and retaining the soil, which has dragged with it. For that the local inhabitants must increase the height of a series of walls built with stones arranged in beds of dry streams. The information was obtained with field tours, interpretation of topographic charts and interviews with users of the presas. We conclude that the permanence of the system depends on the knowledge to control runoff, the availability of plant varieties adapted to the local ecology, the widespread use of oxen for agricultural work, as well as the social arrangements that allow the maintenance of the hydraulic infrastructure.