The transport of suspended solids from the soil to continental waters represents one of the main causes of water quality degradation. Not only volume-wise but also because it represents a means of transport for dangerous substances. The aim of this paper is to know the impact of the runoff on the suspended solid transport in a small catchment in Galicia (Northwest of Spain). The surface area of the selected watershed is of 16 km2 where the average slopes are of 19%. The climate in the study area is humid temperate. The mean rainfall in Galicia is in the range of 1400-1500 mm. The selected catchment represents typical soil and management conditions of wide areas in the Northwest of Spain. Land use is agroforestry with great forest extensions (over 70% of the total). The agriculture (over 30% of the total) is non-intensive and the tillage is conventional. The soil parent material is schist and the soils are relatively deep medium-textures, mainly loam and silt-loam. The study period ranges from December 2004 to November 2005. The content of suspended solids in the waters that drain a river catchment is studied under 2 different hydrological conditions: i) in baseflow conditions and ii) during eleven precipitation events. The information obtained during this study proves that in base flow conditions the concentrations of the suspended solids are relatively low and the relation with the flow is highly disperse. Normally the values of these are under 25 mg/L and the average contents around 6 mg/L. On the other hand, in the precipitation events the concentration of suspended solids increases drastically until it exceeds, in some cases, contents of 500 mg/l. Although the magnitude of the concentration varied in each event, the behavior of the distribution of solids with the flow was similar in all the events that were studied, adjusting to the exponential function. This could be due to humidity conditions before the event and consequently to the variability of these. The solids show an increase in the rising limb of the hydrogram, which is linked to the high transport values and the degradation of the sediment. Once it has passed the flow peak the amount of solids decreases rapidly in a similar way to the flow but more pronounced. Throughout the eleven events studied the estimate load of suspended solids has varied between 477 kg and 24848 kg, which means a specific load of 29.21 kg/ km2 and 1519 kg/ km2 respectively. As can be seen from the two types of sampling done most of the suspended solids were transported during the events. Consequently, the prevention of massive arrival of sediments to the rivers passes necessary by the application of the best management practices, which will enable the adequate vegetation covering. This will not only prevent erosion, but it will also have an influence on the deposition of sediment in the catchment and reduce the runoff at the water course.