Shallow landslides and vegetation at the catchment scale: A perspective

Abstract. Topographic index-based hydrological models have gained wide use to describe the hydrological control on the triggering of rainfall-induced shallow landslides at the catchment scale. A common assumption in these models is that a spatially continuous water table occurs simultaneously at any point across the catchment. However, during a rainfall event isolated patches of subsurface saturation form above an impeding layer and hydrological connectivity of these patches is a necessary condition for lateral flow initiation at a point on the hillslope. Here, a new hydrological model is presented, which allows to account for the concept of hydrological connectivity while keeping the simplicity of the topographic index approach. A dynamic topographic index is used to describe the transient lateral flow that is established at a hillslope element when the rainfall amount exceeds a threshold value allowing for (a) development of a perched water table above an impeding layer, (b) hydrological connectivity between the hillslope element and its own upslope contributing area. A spatially variable soil depth is the main control of hydrological connectivity in the model. The hydrological model is coupled with the infinite slope stability model, and with a scaling model for the rainfall frequency-duration relationship to determine the return period of the critical rainfall needed to cause instability on three catchments located in the Italian Alps. The results show the good ability of our model in predicting observed shallow landslides. The model is finally used to determine local rainfall intensity-duration thresholds that may lead to shallow landslide initiation.

Download Full-text

Rainfall-triggered shallow landslides at catchment scale: Threshold mechanics-based modeling for abruptness and localization

Water Resources Research ◽

10.1002/wrcr.20418 ◽

2013 ◽

Vol 49 (10) ◽

pp. 6266-6285 ◽

Cited By ~ 37

Author(s):

J. von Ruette ◽

P. Lehmann ◽

D. Or

Keyword(s):

Shallow Landslides ◽

Catchment Scale

Download Full-text

Shallow landslide prediction in the Serra do Mar, São Paulo, Brazil

Natural Hazards and Earth System Science ◽

10.5194/nhess-10-1829-2010 ◽

2010 ◽

Vol 10 (9) ◽

pp. 1829-1837 ◽

Cited By ~ 45

Author(s):

B. C. Vieira ◽

N. F. Fernandes ◽

O. A. Filho

Keyword(s):

Sao Paulo ◽

Shallow Landslide ◽

Shallow Landslides ◽

Southeastern Brazil ◽

Mountain Range ◽

São Paulo ◽

Catchment Scale ◽

Landslide Prediction ◽

Serra Do Mar ◽

Number Of Cells

Abstract. Various methods are currently used in order to predict shallow landslides within the catchment scale. Among them, physically based models present advantages associated with the physical description of processes by means of mathematical equations. The main objective of this research is the prediction of shallow landslides using TRIGRS model, in a pilot catchment located at Serra do Mar mountain range, São Paulo State, southeastern Brazil. Susceptibility scenarios have been simulated taking into account different mechanical and hydrological values. These scenarios were analysed based on a landslide scars map from the January 1985 event, upon which two indexes were applied: Scars Concentration (SC – ratio between the number of cells with scars, in each class, and the total number of cells with scars within the catchment) and Landslide Potential (LP – ratio between the number of cells with scars, in each class, and the total number of cells in that same class). The results showed a significant agreement between the simulated scenarios and the scar's map. In unstable areas (SF≤1), the SC values exceeded 50% in all scenarios. Based on the results, the use of this model should be considered an important tool for shallow landslide prediction, especially in areas where mechanical and hydrological properties of the materials are not well known.

Download Full-text

Development of a data-driven model for spatial and temporal shallow landslide probability of occurrence at catchment scale

Landslides ◽

10.1007/s10346-020-01592-3 ◽

2020 ◽

Author(s):

M. Bordoni ◽

V. Vivaldi ◽

L. Lucchelli ◽

L. Ciabatta ◽

L. Brocca ◽

...

Keyword(s):

Roc Curve ◽

Dynamic Change ◽

Joint Probability ◽

Shallow Landslide ◽

Shallow Landslides ◽

Multivariate Adaptive Regression Splines ◽

Data Driven ◽

Catchment Scale ◽

Probability Of Occurrence ◽

Area Under Roc Curve

AbstractA combined method was developed to forecast the spatial and the temporal probability of occurrence of rainfall-induced shallow landslides over large areas. The method also allowed to estimate the dynamic change of this probability during a rainfall event. The model, developed through a data-driven approach basing on Multivariate Adaptive Regression Splines technique, was based on a joint probability between the spatial probability of occurrence (susceptibility) and the temporal one. The former was estimated on the basis of geological, geomorphological, and hydrological predictors. The latter was assessed considering short-term cumulative rainfall, antecedent rainfall, soil hydrological conditions, expressed as soil saturation degree, and bedrock geology. The predictive capability of the methodology was tested for past triggering events of shallow landslides occurred in representative catchments of Oltrepò Pavese, in northern Italian Apennines. The method provided excellently to outstanding performance for both the really unstable hillslopes (area under ROC curve until 0.92, true positives until 98.8%, true negatives higher than 80%) and the identification of the triggering time (area under ROC curve of 0.98, true positives of 96.2%, true negatives of 94.6%). The developed methodology allowed us to obtain feasible results using satellite-based rainfall products and data acquired by field rain gauges. Advantages and weak points of the method, in comparison also with traditional approaches for the forecast of shallow landslides, were also provided.

Download Full-text

A new shallow landslides inventory for Southern Lunigiana (Tuscany, Italy) and analysis of predisposing factors

Rendiconti online della Società Geologica Italiana ◽

10.3301/rol.2018.66 ◽

2018 ◽

Vol 46 ◽

pp. 149-154

Author(s):

Enrico D'Addario ◽

Emanuele Trefolini ◽

Elisa Mammoliti ◽

Michele Papasidero ◽

Vincenzo Vacca ◽

...

Keyword(s):

Shallow Landslides ◽

Predisposing Factors

Download Full-text

Groundwater protection and diffuse nitrogen emissions to surface waters – which catchment areas have to be considered?

Water Science & Technology Water Supply ◽

10.2166/ws.2007.072 ◽

2007 ◽

Vol 7 (3) ◽

pp. 103-110

Author(s):

C. Schilling ◽

M. Zessner ◽

A.P. Blaschke ◽

D. Gutknecht ◽

H. Kroiss

Keyword(s):

Surface Water ◽

Total Nitrogen ◽

Surface Waters ◽

Flow Path ◽

Emission Model ◽

Catchment Scale ◽

Danube Basin ◽

Nitrogen Emissions ◽

Nitrogen Levels ◽

Catchment Areas

Two Austrian case study regions within the Danube basin have been selected for detailed investigations of groundwater and surface water quality at the catchment scale. Water balance calculations have been performed using the conceptual continuous time SWAT 2000 model to characterise catchment hydrology and to identify individual runoff components contributing to river discharge. Nitrogen emission calculations have been performed using the empirical emission model MONERIS to relate individual runoff components to specific nitrogen emissions and for the quantification of total nitrogen emissions to surface waters. Calculated total nitrogen emissions to surface waters using the MONERIS model were significantly influenced by hydrological conditions. For both catchments the groundwater could be identified as major emission pathway of nitrogen emissions to the surface waters. Since most of the nitrogen is emitted by groundwater to the surface water, denitrification in groundwater is of considerable importance reducing nitrogen levels in groundwater along the flow path towards the surface water. An approach was adopted for the grid-oriented estimation of diffuse nitrogen emissions based on calculated groundwater residence time distributions. Denitrification in groundwater was considered using a half life time approach. It could be shown that more than 90% of the total diffuse nitrogen emissions were contributed by areas with low groundwater residence times and short distances to the surface water. Thus, managing diffuse nitrogen emissions the location of catchment areas has to be considered as well as hydrological and hydrogeological conditions, which significantly influence denitrification in the groundwater and reduce nitrogen levels in groundwater on the flow path towards the surface water.

Download Full-text

River Quality Models for Consent Setting in England and Wales

Water Science & Technology ◽

10.2166/wst.1989.0303 ◽

1989 ◽

Vol 21 (8-9) ◽

pp. 1015-1024 ◽

Cited By ~ 4

Author(s):

C. P. Crockett ◽

R. W. Crabtree ◽

I. D. Cluckie

Keyword(s):

River System ◽

Quality Model ◽

Catchment Scale ◽

Quality Models ◽

England And Wales ◽

Future Developments ◽

Statistical Framework ◽

River Quality ◽

National Approach

In England and Wales the placing of effluent discharge consents within a statistical framework has led to the development of a new hybrid type of river quality model. Such catchment scale consent models have a stochastic component for the generation of model inputs and a deterministic component to route them through the river system. This paper reviews and compares the existing approaches for consent modelling used by various Water Authorities. A number of possible future developments are suggested including the potential need for a national approach to the review and setting of long term consents.

Download Full-text