**Abstract**

The existing high alluvial risk Basin Lluta "Chile," due to the presence of large mountains subject to inclement weather, coupled with the growing urban pressure to use sectors downstream increasingly exposed to this type of event, justify studies of the behavior of debris flows and the ability to mitigate its effects by the construction of protection and control. For this purpose, made the hidrogeomorfológica map for this basin. The surface of this basin is 3447 km2 and is in a desert area. It is characterized by low rainfall and therefore all its soils are devoid of vegetation except for the low part of the valley where the land use is agricultural. The natural regime has permanent basin runoff to the sea all year round with an average flow of 0.45–1.44 m3 seg. The impact has increased the flow, but homogeneity is not presented with the full extent of the basin, showing notable spatial differences in the level of danger she originates. Different from what was described flood of 2001, which was reflected in the lower basin Lluta where road infrastructure was badly damaged by the effects of scouring and landslides, resulting in this reconstruction of road and railway bridges, implying a strong investment in works of river bank protection upstream of the bridges.

**Keywords:** alluvia risk, debris flow, runoff, water balance, hydrographic basin, infiltration, flooding, mitigation, runoff, discharge, suspended sediment, hydrogeomorphological chart
