Mass movements
(Monitoring frequency: once a year)
A periodical survey of mass movement processes is required because the catchment is strongly affected by shallow mass movement and deep seated landslides. Shallow mass movements are diffuse especially in agricultural land and their thresholds are related to medium high magnitude hydrological event. The large diffusion in the arable lands of the mass movements and the large portion of mobilized topsoil influence directly the soil properties because disarticulate the soil and promote the use of bulldozers in order to reshape the mobilized mass and re-establish an usable arable surface.
The planned survey frequency (1 year frequency in the end of winter -early spring) will allow updating and tracking changes in more affected areas. The objective of this survey is to identifies the soil unit and lithology that are most affected from shallow landslides. During the periodical survey (at the end of the winter - early spring) a measurement of a representative sample of shallow landslides will be made. Suring the survey measurement of depth of soil layer involved, slope gradient, position (UTM coordinates) extension of landslides areas, particular geomorphological characteristics and processes (flow slide, translational landslides, mud flow..), type of soil and lithology of substratum, main land use and management techniques, distance form permanents drainage line and the level of connectivity with it. The survey will allow identification of the thresholds for the formation of landslides for each particular HBU in the basin. The survey will allow assessment of the percentage of affected areas in each HBU and the assessment of volume involved. This database will be used for the basic development of extension of PESERA model for the soil loss due to shallow landsliding (WP 5.2.1).
