Articles | Volume 18, issue 2
Research article
28 Feb 2018
Research article |  | 28 Feb 2018

Physically based approaches incorporating evaporation for early warning predictions of rainfall-induced landslides

Alfredo Reder, Guido Rianna, and Luca Pagano

Abstract. In the field of rainfall-induced landslides on sloping covers, models for early warning predictions require an adequate trade-off between two aspects: prediction accuracy and timeliness. When a cover's initial hydrological state is a determining factor in triggering landslides, taking evaporative losses into account (or not) could significantly affect both aspects. This study evaluates the performance of three physically based predictive models, converting precipitation and evaporative fluxes into hydrological variables useful in assessing slope safety conditions. Two of the models incorporate evaporation, with one representing evaporation as both a boundary and internal phenomenon, and the other only a boundary phenomenon. The third model totally disregards evaporation. Model performances are assessed by analysing a well-documented case study involving a 2 m thick sloping volcanic cover. The large amount of monitoring data collected for the soil involved in the case study, reconstituted in a suitably equipped lysimeter, makes it possible to propose procedures for calibrating and validating the parameters of the models. All predictions indicate a hydrological singularity at the landslide time (alarm). A comparison of the models' predictions also indicates that the greater the complexity and completeness of the model, the lower the number of predicted hydrological singularities when no landslides occur (false alarms).

Short summary
Recently, landslides affecting pyroclastic covers of Campania Region caused many deaths and huge costs. The development of early warning systems represents a key issue for the area. However, the features of such soils make the development of reliable predictive tools challenging. The relevance of accounting for evaporative losses in slope hydrological balance regulating safety conditions is here discussed. To that end, the 2005 landslide in Nocera Inferiore is used as test case.
Final-revised paper