Response of Terraced Slopes to a Very Intense Rainfall Event and Relationships with Land Abandonment: A Case Study from Cinque Terre (Italy)

Abstract

Agricultural terraces represent one of the best ways to prevent land degradation in hilly and mountainous landscapes. However, it is widely recognized that terraced slopes are threatened by agricultural land abandonment. In the literature, very few studies have quantitatively examined the influence of agricultural abandonment on the stability of terraced slopes. The goal of this research is to investigate the relationships between landslide magnitude and land use conditions of agricultural terraced slopes. In particular, Light Detection And Ranging (LiDAR) elevation data, coupled with aerial photo interpretation, were used for the computation of shallow landslide mobilized volumes on terraced slopes affected by an intense rainfall event. We performed the analysis within the Vernazza basin, a small Mediterranean coastal catchment located in the “Cinque Terre” area (Liguria, northwestern Italy), comparing pre‐event and post‐event LiDAR datasets. The results revealed that abandoned terraced slopes have been affected by a higher amount of mobilized debris volumes than still‐cultivated terraces. Furthermore, terraces abandoned for a short time (less than 25–30 years) resulted in the most hazardous land use class, showing erosion rates that were approximately 2 and 3 times higher than terraced slopes abandoned a long time ago (more than 25–30 years) and still‐cultivated terraces, respectively. These findings highlight that land abandonment and agricultural mismanagement can intensify the magnitude of rainfall‐induced shallow landslides. Copyright © 2016 John Wiley & Sons, Ltd.

Mass soil movement on terraced landscapes of the Mediterranean mountain areas: a case study of the Iberian Range, Spain

“…This is partly because of the poor connectivity which usually occurs between the slopes and the channels in terraced environments and which, in most cases, is reduced due to an increase in vegetation following agricultural abandonment (López-Vicente et al, 2015, 2016. However, with high intensity precipitation, Brandolini et al (2016) have verified that landslides on abandoned terraces mobilize large volumes of soil, much higher than those calculated for our area of study. These authors state that maintaining terraces is a good method of mitigating geo-hydrological risks.…”

Urban Geomorphology in Coastal Environment: Man-Made Morphological Changes in a Seaside Tourist Resort (Rapallo, Eastern Liguria, Italy)

“…The effects of urbanization and morphological modifications and land use changes (Brandolini et al 2017) increased geo-hydrological risk both in terms of vulnerability and hazard; the variation of the rainfall regime resulted in a more frequent occurrence of short but intense events increasingly concentrated in autumn (Faccini et al 2005, Del Monte et al 2015.…”

Agricultural Terraces Special Issue Preface

“…The soil loss was determined, and the technique of botanical benchmark was used. According to this methodology, the estimated total soil lost over 44 years was about 692 Mg ha −1 , confirming that the water and management practices adopted in the vineyard with a high slope gradient have played a relevant role in countering the high erosion rate Brandolini et al (2018). analysed the response of terraced slopes to a very intense rainfall event and explored the relationships with land abandonment in Cinque Terre (Italy).…”