A New Coastal Erosion Risk Assessment Indicator ...

Environ. Process. https://doi.org/10.1007/s40710-018-0295-6 O R I G I N A L A RT I C L E

A New Coastal Erosion Risk Assessment Indicator: Application to the Calabria Tyrrhenian Littoral (Southern Italy) Fabio Ietto 1 & Nicola Cantasano 2 & Gaetano Pellicone 2

Received: 14 December 2017 / Accepted: 24 March 2018 # Springer International Publishing AG, part of Springer Nature 2018

Abstract Littoral plains are exposed to natural phenomena, such as sea-waves, tides, rainfalls and sea-level rise, but also to human pressure, determining a growing exposure of the natural and man-made environments to hazard conditions. Through this work, a new kind of multiple approach is proposed to evaluate the coastal risk due to erosion processes, which was first tested on the Calabria Tyrrhenian coast. The resulting data show that 35% of the coastal stretches are classified into very high risk category, 30% into high risk, 28% into medium risk and only 7% into low risk. The coastal areas, characterized by high and very high levels of risk, are formed by sandy beaches and are distributed mainly at the northern side of the regional coastline while the southern part, distinguished mainly by rocky outlines, shows lower risk levels. The comparison between the calculated risk values and the real conditions of the damage state shows a good correspondence, testifying the pertinence of the new methodology. The latter is based on indices with data easily available, making the procedure fast and simple to use and applicable mainly in large scale surveys. The achieved good results suggest that the new methodology used to evaluate the coastal risk condition may be also extended to other Mediterranean beaches. Keywords Coastal vulnerability assessment . Coastal exposure assessment . Sandy beaches . Risk levels . Calabria Tyrrhenian coasts

* Nicola Cantasano [email protected] Fabio Ietto [email protected] Gaetano Pellicone [email protected]

1

Department of Biology, Ecology and Earth Science, Università della Calabria, 87036 Arcavacata di Rende (CS), Italy

2

National Research Council, Institute for Agricultural and Forest Systems in the Mediterranean, Rende Research Unit, Via Cavour 4/6, 87036 Rende, CS, Italy

Ietto F. et al.

1 Introduction Coastal zone is defined as a narrow strip where its seaward boundary is the shoreline, while its landward side is up to 200 m from the inland limit of the shore (European Commission 2011). Therefore, the coastal zone is a broad transition area where marine and terrestrial ecosystems interact. Nowadays, the demographic pressure is more stressed in littoral areas than on global average. Indeed, 10 % of the world’s population is located in littoral plains causing significant changes to seaboard system (McGranahan et al. 2007; Hugo 2011; Parthasarathy and Natesan 2015). This global trend is going to increase in many littoral areas, as a result of a coastward migration by population and a growth of tourism demand (Wong et al. 2006; McGranahan et al. 2007). The littoral plains are also exposed to hydro-meteorological phenomena, such as: sea-waves, wind, tides and rainfalls, which can reach extreme levels due to ongoing climate change (e.g., Bryant 2005; Castillo et al. 2012). Thus, natural phenomena, coupled to human pressure, produce a growing exposure of the littoral plains to hazard conditions. Indeed, destruction of human infrastructure, loss of coastal estuaries and natural environments caused by coastal erosion, coastal inundation and pollution are the most frequent hazard conditions in coastal areas producing economic instability for mankind (Nicholls et al. 2007; Parry et al. 2007; Forbes 2009; Ietto et al. 2014). In this regard, there is a big concern worldwide concerning coastal risk, due to erosion processes, and its potential impact on natural and anthropic environment (e.g., Tran and Shaw 2007; Cooper and McKenna 2008). Coastal risk may be explained as the combination between the probability of a climatic event and its negative consequences on natural areas or on human activities (e.g., UNISDR 2009; Dawson et al. 2009; Mokrech et al. 2011). The assessment of the risk depends on the following elements: vulnerability and exposure. The vulnerability is conceived in terms of predisposition of a specified coastal system to suffer damage by a particular climate-related event (Jones and Boer 2004; Adger et al. 2004). Coastal exposure is understood as the presence in littoral areas of people, human activities, infrastructures or other human elements and/or ecosystems that could undergo damage by a particular climatic phenomenon. Therefore, the exposure drives the final tally of damage and so the grade of the final coastal risk (IPCC 2014). The evaluation of coastal vulnerability is a controversial issue in coastal engineering and many authors produced different methods in order to estimate it. The used procedures have progressively evolved from very simple approaches (e.g., Bruun 1962) to more consistent methodologies (e.g., Weis et al. 2016) as the knowledge on physical factors influencing the coastal zone has been improved. Generally, these procedures have been based on semiquantitative and quantitative indices. The first kind encloses the subjective assessment of geomorphologic indicators, while the second one quantifies the importance of physical and geomorphological phenomena on coastal environment. For example, since the nineties, several vulnerability indices have been developed by many authors in order to assess the effects of sealevel rise in the oceanic littoral areas (e.g., Gornitz 1990; Hughes and Brundrit 1992; Barnett and Adger 2003; Hedge and Rejn 2007; Lichter and Felsenstein 2012, and many others). Successively, more complex indices have been suggested in many researches in order to integrate the coastal risk zoning. Among the most recent: Alexandrakis and Poulos (2014) advanced a Beach Vulnerability Index useful for the assessment of coastal vulnerability to erosion processes; Greco and Martino (2016) suggested a single risk index, called Coastal Critical Index, on the base of morphological and socio-economic variables; Weis et al. (2016) proposed a spatial model of vulnerability assessment able to integrate exposure, sensitivity and adaptive capacity into one integrated vulnerability index.

A New Coastal Erosion Risk Assessment Indicator: Application to the...

Several vulnerability indices have been tested also in Mediterranean coastal regions to estimate the consequences of erosion processes on human activities and infrastructures (e.g., Domínguez et al. 2005; Martínez and Anfuso 2008; Anfuso and Del Pozo 2009; Alberico et al. 2012; Alberico and Petrosino 2015). The Mediterranean basin is highly vulnerable to sea energy and exposed to coastal erosion due to its low-lying coastal areas (Jeftic et al. 1992; Nicholls and Hoozemans 1996; Alpar 2009). In such context, the EU Water Framework Directive 2000/60/EC and the late ones for an Integrated Coastal Zone Management (ICZM) (European Commission 2002; European Commission 2008) and for the management of flood risk (European Commission 2007), suggest particular attention to the assessment of territorial and environmental risks in coastal areas. Thus, according to European Directives, the protection of infrastructures, cultural heritage and natural ecosystems in littoral areas can be reachable through a policy able to mediate an agreement between human needs and respect for natural resources (Cantasano 2013; Cantasano et al. 2017). In Italy, the guidelines of the national coastal management are based on a complex set of Legislative Decrees (n. 152/2006, n. 49/2010 and n. 90/2010) conforming to the previous European Directives. Nowadays, this national Legislative pattern appears unfit because the decision-making process on coastal management is too fragmented among administrative authorities at national, regional and local levels (Cantasano et al. 2017). Thus, the governance of coastal risks is, mainly, administrated on a reactive basis and the actions are realized when the infrastructure destruction is imminent (Anfuso and Del Pozo 2009). A proactive approach would be requested in order to relieve the potential coastal risks. This procedure should represent the first step for a good politic of coastal management. In this regard, many researches on coastal vulnerability were carried out also in Italian context (Veltri and Morosini 2002; Anfuso and Del Pozo 2009; Di Paola et al. 2013; Benassai et al. 2015; Alberico and Petrosino 2015), where a marked erosional trend occurs (e.g., La Monica and Landini 1983; Caputo et al. 1989; CNR 1997; ISPRA 2013; Pranzini and Rossi 2014). These studies proposed quantitative and complex vulnerability indices based mainly on data hardly available, such as geomorphological and wave-climate quantitative parameters. In this paper, a new methodology of Coastal Risk assessment, based on qualitative and quantitative criteria, is proposed for large areas and tested on the Tyrrhenian coastal stretch of the Calabria (Southern Italy). Calabria coastal zone is one of the most damaged areas in Italy because of the erosive trend of its coastline (D'Alessandro et al., 1998, 2002, 2011; Ietto 2001; GNRAC 2006; Bellotti et al. 2009; Ietto et al. 2012a, 2014). The tested area is a coastal region of about 186 km in length that is exposed to strong erosional processes. The proposed methodology is consistent with previous studies concerning the application of the vulnerability indices in Italian littoral (Anfuso and Del Pozo 2009; Di Paola et al. 2013; Alberico and Petrosino 2015; Benassai et al. 2015) than elsewhere (McLaughlin and Cooper, 2010; Bagdanavičiūtė et al. 2015; Denner et al. 2015; Loinenak et al. 2015; Sano et al. 2015; Sudha Rani et al. 2015; Semedi et al. 2016). Thus, the new approach was conceived for the evaluation of coastal risk caused by sea-wave conditions. The methodology takes into account mainly the natural characteristics of the coast and the human activities able to produce a reduction or a strengthening of wave surge events. Several authors (e.g., Samaras and Koutitas 2012, 2014; Ietto et al. 2015; Antronico et al. 2017) widely discussed the effects on coastal areas caused by rivers, mainly regarding the evaluation of vulnerability and the assessment of coastal risk connected to flooding and alluvial events. Rivers and natural streams have strong effects on coastal environments, because they are the main nourishing systems of the beaches (e.g., Bittencourt et al., 2005; Bi et al., 2010). Consequently, the effects of the drainage streams on

Ietto F. et al.

coastal vulnerability are related to their sediment loading capacity, to the intensity and direction of longshore-currents, to the sediment dispersion in offshore areas and to other factors hardly available. In Calabria region these data are very difficult to obtain because the specific database is missing. Thus, in accordance with previous researches (e.g., Gornitz et al., 1997; Di Paola et al. 2013; Greco and Martino, 2016), the rivers have not been considered in the evaluation of coastal vulnerability, thus limiting estimates to regards only natural and human aspects able to influence directly the sea-wave effects. Instead, in our new approach, the rivers are considered as a natural asset exposed to risks, because the presence of river mouths represents an important and sensitive natural habitat that enriches the environmental heritage of a coastal area and should be protected. Finally, our research takes a step forward, compared to previous ones, because it uses a multidisciplinary approach based on physical, geological and biological parameters able to produce a simple methodology of coastal risk assessment useful for coastal management. Thus, the new methodology would be suitable, also, for other similar urbanized contexts in the Mediterranean area.

2 Study Area The study area lies between Policastro and S. Eufemia Gulfs that are located in the Northern and Central part of the Calabria Tyrrhenian coast (Southern Italy), respectively (Fig. 1). The tested littoral is placed between Praia a Mare village (Province of Cosenza) and Capo Vaticano promontory (Province of Vibo Valentia) and extends mainly at foot slope of the Coastal Chain, where mountains higher than 1500 m lay at 6 km from the coast. The Costal Chain is part of the Calabria-Peloritani Arc (CPA) that is considered an Alpine orogenic belt derived from the deformation of a palaeomargin during the EuropaAdria collisional event (e.g., Vai 1992; Pellegrino and Prestininzi 2007; Barca et al. 2010). The study area falls in the northern sector of the CPA, which is constituted by the three following main complexes (Ogniben 1969; Amodio et al., 1976; Scandone 1982), from bottom to top: (i) the Apennine Units Complex, which is made of dolostones, limestones and marble in Trias-Miocene age; (ii) the allochthonous Alpine Liguride Complex (Tithonian-Neocomian), which is constituted by Alpine metamorphic units including a Cretaceous-Paleogene metapelitic-ophiolitic-carbonate assemblage; and (iii) the Calabride Complex, which is formed by Hercynian and pre-Hercynian gneiss and granite that underwent intense weathering processes (Le Pera and Sorriso Valvo 2000; Ietto et al. 2012b, 2015, 2016a, 2018; Perri et al. 2016; Borrelli et al. 2016). Sedimentary deposits, in Neogene-Quaternary age, discontinuously outcrop in littoral areas. These sedimentary deposits are mainly constituted by unconsolidated sediments (dune or alluvial deposits) or by Miocene arenitic sediments involved in weathering processes (Ietto et al. 2013, 2016b, 2017). The geological variability makes the study stretch coast slightly irregular and mainly characterized by narrow sandy beaches, somewhere interrupted by limited rocky spurs. The main geomorphological features of the beaches can be summarized as follows: the mean beach grain size is equal to 3.51 mm at the swash zone and is 0.84 mm and 0.20 mm at −3.0 m and − 10 m water depth, respectively (Guiducci and Paolella 2004). The drainage network is characterized by the Lao and Savuto rivers and by many steep streams with a potential high sediment transport load, flowing on the examined coast.

A New Coastal Erosion Risk Assessment Indicator: Application to the...

Fig. 1 Study area. The red line shows the coastal stretch examined

Alluvial plains are sometimes present mainly in the central portion, while, rocky cliffs, including pocket beaches, become prevailing in the southern portion of the study area. The Calabria Tyrrhenian coast is characterized by a strong erosional crisis with average retreat rates more than -1 m/year during the last century and mostly close to river mouths (D'Alessandro et al., 1998, 2002, 2011; Ietto 2001; GNRAC 2006; Bellotti et al. 2009; Ietto et al. 2012a, 2014). Several authors (e.g., D'Alessandro et al., 1998, 2002; Ietto 2001; Ietto et al. 2014) asserted that the human factor, such as the incorrect urbanization of littoral areas, represents the main cause of the severe erosion process in Calabria Tyrrhenian coast. Indeed, the unorganized urban development has produced a chaotic overbuilding of the coastal landscape and the destruction of natural environments. Direct consequence of this wild urbanization was the progressive deterioration of coastal landscape and, accordingly, the beginning of a marked erosional trend. Therefore, since 1980, several breakwaters, both on offshore and backshore areas, were built to protect the beaches, residential buildings, and road and railway networks. Nowadays, many urbanized areas on Tyrrhenian coast are exposed to continuous damages producing economic losses (Ietto et al. 2014). In the study area and mainly in the northern

Ietto F. et al.

portion, the coast is characterized by narrow sandy beaches with a strong human impact, where several shore protection structures are placed. The coast of the southern section, instead, is mainly characterized by rocky cliffs that show a lower anthropogenic load with some exceptions.

3 Methodology Previous studies concerning coastal risk assessment were based on many variables. For example, Quelennec (1989) used only three principal variables to identify the risk on coastal areas, whereas, Williams et al. (1993) used 54 variables to assess coastal dune vulnerability. Cooper and McLaughlin (1998) asserted that the majority of authors used between 6 and 19 variables to calculate various indices of coastal risk. In the last decades, Diez et al. (2007) proposed a coastal vulnerability classification based upon six variables, while McLaughlin and Cooper (2010) used 19 variables to obtain an assessment of the coastal vulnerability. In this manuscript, a new procedure is proposed useful to evaluate the coastal risk due to erosion processes. This synthetic method aims to value the coastal risk conditions through an effective assessment of the littoral trend to sustain geomorphological alterations, but also through a qualitative evaluation of human and natural goods prone to suffer damages. The new methodology is based on a fast and simple approach, based on easily available data, applicable mainly at large-scale in Mediterranean coastal areas and, therefore, useless for local conditions. The innovation of this methodology is to suggest a holistic approach suitable for micro-tidal environment integrating the Coastal Vulnerability Assessment (CVA) and the Coastal Exposure Assessment (CEA) into a universal approach. Therefore, the goal of this paper is achieved through two steps concerning the CVA and the CEA evaluations that were obtained by simple qualitative and quantitative variables. The latter were used to define the nature of the coast and its natural and ecological specificities, the degree to which the coast is exposed to wave energy and the principal environmental and socio-economic elements for which coastal erosion could pose a risk. Usually, it is common practice to assign a rank to each variable to indicate its contribution to the evaluation. In this study, following Gornitz (1990), a scale of 1–5 was chosen, with 5 contributing most strongly to vulnerability or to exposure and 1 contributing the least. Subsequently, the combination of the CEA and CVA results allowed to obtain the degree of coastal risk (R), according to the suggestions of the European Union Commission (ISO/IEC 2009) and of previous studies (McLaughlin and Cooper, 2010; Sudha Rani et al. 2015; Benassai et al. 2015). The obtained data were used for the construction of a risk map with different chromatic scale, showing the variability of coastal areas to risk exposure. In order to define the Vulnerability (CVA) and the Exposure (CEA) assessment along the186 km of the studied coast, it was divided into 55 sectors with respect to the analysis of the physical and biological characteristics, as well as, of the urbanization state of the coastal stretch considered. The adopted methodology is described below.

3.1 Coastal Vulnerability Assessment (CVA) Qualitative and quantitative variables were chosen to define a coastal vulnerability assessment. The latter was evaluated starting from the methodology already proposed by Gornitz et al. (1994, 1997) with the inclusion of new variables in order to examine more aspects of coastal conditions. Coastal characteristics, biological characteristics and coastal forcing represent the

A New Coastal Erosion Risk Assessment Indicator: Application to the...

three categories used to assess the coastal vulnerability of the study area (Table 1). Each category is composed of different variables that were represented by a value between 1 and 5. Fourteen variables were deemed important in order to define the geological and geomorphological nature of the coast, the biological characteristics constituting a natural defensive coastal system and the degree to which the coast is exposed to wave energy. In particular, with reference to Table 1, the coastal characteristics category includes the following variables: (1) Landform, which concerns the geomorphological kind of the considered beach. (2) Solid geology, which represents the rock type constituting the littoral area. (3) Elevation, which refers to the topographic altitude of the beach. (4) Width of the beach, which shows the actual amplitude of the beach and it is considered negligible in rocky and high coast. (5) Breakwaters, which indicate the presence or not of the coastal protective structures, such as: longitudinal, perpendicular and adherent breakwaters both emerged and submerged. (6) Beach position with respect to harbor, which is applied only in coastal sectors where a harbor structure is present (Uda 2010; Tsoukala et al. 2015). Indeed, the harbor structure represents an artificial obstruction to the natural sediment transport in the shore area (e.g., Sarma 2015). In this case, the ranking value ranges between −3 and + 5. The negative value (−3) is assigned to the beach located on the upcoast side with respect to the harbor structure, where a strong deposit of sediment occurs; vice versa, the highest vulnerability (value ±5) is assigned on the beach located on the downcoast side with respect to the harbor structure, due to decrease of sedimentary nourishment. (7) Subtidal morphology, which refers to the type of morphology of sea bed and to the grain size for sandy morphology, observed till 5 m bathymetry; obviously, fine sediments are more vulnerable to erosion action. (8) Subtidal slope, which shows the seabed slope from the coastal swash zone until the −5 m bathymetry; deeper slopes imply higher wave energy in the littoral areas. (9) Subtidal dune ridges, which indicate the possible presence or not of submerged sedimentary deposits close to the coast, both continuous and discontinuous, such as: bars or dunes; their presence represents a natural defense system against wave energy. The biological characteristics category includes only two variables (Table 1), which were deemed significant to the coastal vulnerability assessment: Posidonia meadows (10) and dune ridges (11). The presence of Posidonia oceanica (L.) Delile meadows in subtidal zone is considered a good natural defense system against erosion processes due to its capacity to obstruct the sediment transport and to reduce the energy of sea swells and current movements (Fonseca and Cahalan 1992; Koch and Gust 1999; Bradley and Houser 2009). In backshore area, the presence of dune ridge is instead a natural geomorphological defense (e.g., Saye et al. 2005; Spalding et al. 2014), more or less effective if vegetated or un-vegetated, respectively (Bhalla 2007; Feagin et al. 2010). The coastal forcing category is composed of three variables (Table 1): storm probability (12), effective fetch (13), and maximum wave height (14), which give information about the exposure of the coast to wave energy. In particular, storm probability indicates the main source direction of the storm on the base of the coastal orientation. Maximum fetch is referred to effective fetch (Fig. 2a, b) that was computed through the methodology proposed by Saville (1954). Effective fetch indicates the length of seawater over which the winds effectively produce waves, considering the effect of geographic fetch shape and directional spreading of wave energy. Finally, maximum wave height is referred to the greater wave heights recorded (Fig. 2c) that are consistent with effective fetch data. It is well known that in CVA other factors, such as torrent damaging, water abstraction, river flow regulation, groundwater consumption, changes in suspended sediment loading, etc.,

Biological characteristics Coastal forcing

V8) Subtidal slope*** V9) Subtidal dune ridges V10) Posidonia meadows V11) Dune ridges* V12) Storm probability**** V13) Effective Fetch (km) V14) Maximum wave height (m)

V3) Elevation (m) V4) Width of the beach* (m) Coastal characteristics V5) Breakwaters V6) Beach position with respect to harbor** V7) Subtidal morphology 5

4

high resistances cliff; medium resistances cliff; gravel and boulder ridges sand beaches; plutonic rocks medium-low grade sedimentary rocks sedimentary metamorphics well cemented rocks poor cemented >30 20 to 30 10 to 20 5 to 10 >150 100–150 50–100 10–50 present occasionally present beach on updrift side

3

V1) Landforms V2) Solid geology

2

1 (−3**)

Variables

Table 1 Coastal Vulnerability Assessment (CVA): classification scheme (*only for sand beaches; ** applied only on harbor areas; *** slope calculated from swash zone until bathymetric of -5 m; **** based on coastal orientation)

Ietto F. et al.

A New Coastal Erosion Risk Assessment Indicator: Application to the...

Fig. 2 a Exposure of the coast to storm surges; b direction and relative length of the geographic and effective fetch; c significant wave height and mean wave direction during the period 2002–2007

could be important for a sound coastal risk assessment, but unlike in other methods (e.g., Harvey et al. 1999; Small and Nicholls 2003; Ozyurt 2007), these aspects are left out in our methodology. These data could be useful for a very detailed evaluation of the coastal risk but this kind of approach is outside the aim of our method based on a broader scale. Similarly, also historical shoreline change is not considered in our proposed approach because CVA is based just on valuing the human and natural features able to condition coastal stretches to suffer damages by natural events. In this work the qualitative and quantitative variables belonging to coastal characteristics category, were defined through aerial photo interpretation, field surveying and bibliographic data (CNR 1997). Biological characteristics were determined on the base of field surveying and literature data (Cantasano 2017). Offshore wave climate, useful to define the coastal forcing category, was obtained through the statistical analysis of the data provided by the Italian Sea Wave Measurement Network (RON 2007) from the Cetraro buoy. The latter is located (39°27′2^N; 15°55′1″E) offshore Cetraro village, since 1999. This wave-measuring station is a surface buoy, well representing the wave climate of the study area because it is located in the middle of the surveyed zone and, indeed, it supplies the only dataset available for the wave climate of the Tyrrhenian side of Calabria. The collected data can be considered representative of the offshore wave conditions in the study area, according to the Wind and Wave Atlas of the Mediterranean Sea (Medatlas Group 2004). The period covered by the

Ietto F. et al.

wave data ranges from 2002 to 2007, suitable for a sound assessment of sea-wave climate, showing values of significant wave height and mean wave direction (Fig. 2c). The results of the analysis show that the study area is frequently affected by wave conditions associated to significant wave heights lower than 3 m, coming mainly from NW direction. The same direction generates also rare waves with heights less than 5 m. Wave heights equal to or greater than 5 m mainly come from the directions W-WSW. However, in the winter, stormy conditions generate mainly wave fields traveling from subsector WSW-WNW. Finally, the sum of the values assigned to each variable, allowed us to calculate the score of coastal vulnerability (VT) in each considered sector.

3.2 Coastal Exposure Assessment (CEA) Previous studies concerning the coastal exposure assessment in Italy (e.g., Anfuso and Del Pozo 2009; Di Paola et al. 2013; Benassai et al. 2015; Alberico and Petrosino 2015) are based on quantitative data concerning density of population and socio-economic factors in the littoral zone. In this manuscript, the coastal exposure assessment aims to evaluate the exposure degree of economic, civil and environmental elements that could suffer damages by wave energy. The exposure degree was valued on the base of several qualitative variables representative of land use, economic activities, environmental characteristics, as well as, resident population in the coastal area. The data were obtained by aerial photo interpretation and field surveying. The exposure degree ranges in a scale of 1–5, where 5 shows the strongest exposure and 1 the least one. Nine variables were chosen to define the degree to which the human, cultural and environmental characteristics are exposed to wave energy in each sector. In particular, with reference to Table 2, the economic, social and environmental possible damages are represented by the following variables: (1) Cultural heritage, which indicates the presence or not of historic and cultural evidences of the community. (2) Land use, which concerns the natural state or the human utilization of littoral areas. (3) Urbanization in beach area, which is referred to the presence of residential and/or touristic buildings within 300 m from coastline. (4) Population, which shows human presence or not. (5) Road, which shows the presence or not and the typology of roads exposed to wave energy. (6) Railway, which indicates railway exposure or not to wave energy. (7) Conservation designation, which gives information about the presence of areas subject to a conservation order. (8) Mouth river, which refers to the presence or not of important and delicate natural environment and its extension in function of the river typology. (9) Priority habitat, which indicates its presence or not into each sector.

3.3 Coastal Risk Levels The European Union Commission (ISO/IEC, 2009) defines the risk as Bthe probability of harmful consequences, or expected losses (deaths, injuries to property, livelihoods, disruption to economic activities or environment hazards), resulting from interaction between vulnerability and exposure^. Therefore, the risk (R) can be obtained through the following simple definition: R¼VxE where V is the coastal vulnerability (susceptibility of a coastal area to be affected by either inundation and/or erosion), E is the exposure described by the socio-economic and environmental values (exposure of an element or a group of elements that should suffer damages).

Economic, social and environmental possible damage Absent Absent Absent Absent Absent Absent Absent

Absent Rocky cliffs

E1) Cultural heritage E2) Landuse

E3) Urbanization in beach area E4) Population E5) Road E6) Railway E7) Conservation designaction E8) Mouth river E9) Priority habitat

1

Variables

Table 2 Coastal Exposure Assessment (CEA): classification scheme

Small river

Footpaths

stream

Forest; Rough;

3

Occasionally present Occasionally present Minor access roads

scrub

2

Medium river

Municipal road

Agricultural land; Amenity grass;

4

Present Urban; Residential; Touristic; Industrial; Present Present Highway Present Present Large river Present

5

A New Coastal Erosion Risk Assessment Indicator: Application to the...

Ietto F. et al.

In this paper, the coastal risk (R) was obtained through the product between the sum of the rankings assigned to each variable (VT) of the coastal vulnerability assessment (CVA; Table 1) division by the number of considered variables (nv), and the sum of the ranking of variables (ET) used for coastal exposure assessment (CEA; in Table 2) division by the number of respective variables (ne), as follows:  Risk ðRÞ ¼

VT nv



ET ne



where: VT ET n

= V1 + V2 + V3 .... + V14; = E1 + E2 + E3 .... + E9; = number of considered variables: (nv = 14 and ne = 9).

Finally, the risk values obtained for the 55 sectors were classified in four different classes, as follows: R4 (very high risk): high danger for financial, social and environmental activities; R3 (high risk): significant damage for financial, social and environmental activities; R2 (medium risk): possible damage for financial, social and environmental activities; R1 (low risk): low or negligible damage for financial, social and environmental activities.

3.4 Risk Map The representation of the achieved results is an important process to define the dynamics and the distribution of different degrees of risk. For this analysis, the ArcGIS 10.x software was used in order to prepare a Risk map, which allowed to visualize, to analyze and to understand patterns and their relationships. For ensuring proper visualization and representation of adequate details, the scale used was 1:250.000, while the coordinate system was a UTM WGS84 fuse 33. The construction of the map was obtained, firstly, through the selection of the useful information in order to include the variables investigated. The next step was the classification of the variables; in this way, it was possible to distinguish grouping attributes into a discernible class making the maps more legible. In this paper, four different risk degrees were recognized with distinct color gradients for each of them: R1 class in blue, R2 class in green, R3 class in yellow and R4 class in red, while for representing the coastline, a one km wide buffer was implemented. This color scale was chosen with the aim to clearly represent the different classes of risk providing a simple consultation of the maps.

4 Results and Discussion Field surveying highlighted that the study coast is, mainly, characterized by sandy beaches without coastal dunes (57%). Vegetated coastal dunes represent a natural reinforcement against beach erosion and characterize 20% of the examined coastline (Fig. 3), while un-vegetated coastal dunes cover only 6% of sandy beaches. Just some sectors are constituted by vegetated

A New Coastal Erosion Risk Assessment Indicator: Application to the...

Fig. 3 Lengths of coastal sectors and proportional distribution of rocky and sandy beaches in the coastline analyzed

sandy beaches that are very fragmented and limited by human infrastructures (Fig. 4). The remaining coast, covering 17% of the studied seaboard, is composed of rocky outlines including high cliffs, rocky ridges and limited pocket beaches (Fig. 3). The computed risk values (R), obtained through the combination of collected data, range from 4.0 to 15.8 with a mean standard of 10.7. Subsequently, the R scores were divided into 4 categories: low, medium, high and very high risk, according to a linear scale characterized by a step of 3 R units (Table 3). This subdivision was chosen on the base of comparison between computed R values and the real state of the coastal erosion, as well as the exposure to wave energy of human infrastructures, environmental elements and population. So, four different risk levels have been identified: low risk (R1) for Fig. 4 Fragmented vegetated sandy beach limited by human infrastructures in the sector 11 located between Sangineto and Cittadella del Capo villages

Ietto F. et al. Table 3 Risk ranking and relative data achieved Risk classes

Risk ranking

Linear extension of different risk levels (km)

Extension of different risk levels (%)

R1 LOW RISK R2 MEDIUM RISK R3 HIGH RISK R4 VERY HIGH RISK

R < 7.0 7.1 < R < 9.9 10.0 < R < 13.0 R > 13.0

13 52 56 65

7 28 30 35

slight changes, causing possible negligible damage to facilities; medium risk (R2) for conditions of potential damages in the next future; high risk (R3) for important damages, able to cause losses to natural environment and/or temporary conditions of social and economic troubles; very high risk (R4) causing heavy damages and extended conditions of real impending danger for infrastructure and economic goods. The used scheme, which would also be suitable for other Mediterranean coastal areas, highlights that most of the studied coast (± 65%) is characterized by high risk (R3) and very high risk levels (R4) (Fig. 5). In particular, a large portion (± 65 km) of the examined coast was identified as of very high risk level (± 35%) while a high risk level was identified for about 56 km of the littoral (± 30%). The remaining coast was classified as of medium risk level 28% and of low risk level 7% (Fig. 5). Data for each sector are summarized in Table 3 while risk values reported in Fig. 5, from R1 to R4 ranks, have been collated with other studies conducted in the Calabria region (PAI 2015; Autorità di Bacino Regionale 2016) and were compared with field surveys and newspaper reports to check incidental damages suffered in the regional coastline in recent years. All these comparisons have confirmed the results of this research. The data acquired were, then, portrayed in a color-coded map which provides a general comprehensive overview of the intensity and distribution of risk levels amongst the 55 sectors analyzed. The map was distinguished into three frames differentiated for the northern, central and southern sections of the study area (Fig. 6), in order to allow a better visualization of data. The results summarized in the map highlights that most of the coastal sectors belong to a sensitive sedimentary system and are affected by erosional processes and hydrodynamic changes caused by wave climate. In agreement with several

Fig. 5 Length of the shoreline classified for each risk class

A New Coastal Erosion Risk Assessment Indicator: Application to the...

authors (e.g., D’Alessandro et al. 1998, 2002; Ietto et al. 2014), the deteriorated geomorphological state of the Calabria coastline is mainly due to the high human pressure and its heavy urbanization. The latter is mainly characterized by human infrastructures, such as railway or road networks and buildings, located close to the coastal fringe or within the backshore area. The map in Fig. 6 shows that this condition is dominant in the northern and central sectors of the study area which are mainly classified as of high (R3) or very high (R4) level of risk, while medium (R2) risk values were identified for the southern sectors. Sectors with low risk levels (R1) are quite rare and fragmented along the coastal stretch examined (Fig. 6). In these areas, along a narrow strip of coastline (Fig. 7d), the littoral belt is bordered by intense urbanization with a high number of vacation houses, often not used throughout the year (Mura 1995; Cori 1999). Harbor structure is also present close to Cetraro village in sector 14, where strong erosion processes take place. In this regard, several authors asserted that the construction of harbors cause massive accretion of the beaches on upcoast side and concomitant heavy erosion process on downcoast (e.g., Hsu et al. 1993; Anfuso and Del Pozo 2005; Brown et al. 2011; Stancheva et al. 2011; Sarma, 2015). Lower risk conditions, classified as high risk level (R3), characterize other sectors (Fig. 6). In these areas, railway and road networks are mainly exposed to wave climate and coastal risks (Fig. 7c). Recognizing the coastal areas of higher risk represents the priority step to plan the correct mitigation measures able to reduce the erosion processes and the flooding events actually ongoing. Usually, the mitigation strategy for coastal risk can be achieved by decreasing the vulnerability to flooding or by decreasing the exposure from flooding or by combining the two approaches (Pompe and Rinchart, 2008; Luo et al. 2013; Lickley et al. 2014) through coastal defense systems. The most common system of coastal protection is based on Bhard^ measures, such as seawalls, marine bulkheads and detached breakwaters. The research showed that the coastline fringes with higher risk levels (R3 and R4) were often protected by operations of hard engineering consisting of breakwaters and/or seawalls. The scope of the coastal defense systems was to reduce the coastal vulnerability in order to safeguard the human infrastructures against the sea-wave energy. In many coastal areas, the engineering works were ineffective or worsened the vulnerability state of the area. Indeed, in some cases the engineering works

Fig. 6 Risk map of the north, central and southern portions of Calabria Tyrrhenian coast. The numbers are referred to the sectors of the coastal stretch analyzed

Ietto F. et al.

Fig. 7 Examples of risk level in the study area: a sector 36, northern part of Falerna Marina village: low risk (R1); b sectors 39–41, Gizzeria Lido village, medium risk (R2); c sector 18, Guardia Piemontese village, high risk (R3); d sector 22, San Lucido village, very high risk (R4). (see Fig. 6 for the location of the sectors)

caused a shift of the erosional processes on downcoast sides due to a subtraction of sediments from the littoral budget (Fig. 7d). Direct consequence was a reduction of the beach width and an exposition of the private and/or public property, as well as, of road and railway networks, to risk conditions in downcoast areas. Better conditions with lower risk levels are recorded in the southern sectors of the study coast, where rocky cliffs or wide sandy beaches with vegetated coastal dunes are dominant. Indeed, medium risk level (R2) was mainly observed in the southern stretches of the studied coast (Fig. 7b), such as those close to Campora San Giovanni (Sector 33), Nocera scalo (Sector 35), Gizzeria Lido (Sector 40), Cafarone (Sector 41), Pizzo Calabro (Sector 42), Bivona (Sector 47) and Briatico (Sector 49) villages. In these areas, sometimes, the sandy beaches are partially protected by vegetated coastal dunes that give a fair stability. Finally, the southern sectors located close to Vibo Valentia (Sector 44), S. Irene (Sector 50), Zambrone-Parghelia (Sector 52) villages and some limited coastal stretches of the northern sectors (San Nicola Arcella and Cirella villages in Sector 4 and 6, respectively) are the less risky areas (R1). These conditions are mainly due to rocky coasts more resistant to erosion process and wave climate scenarios. Similar condition of low risk level was also observed in some southern sectors characterized by wide beaches with large vegetated dune systems (e.g., Sector 36 in Fig. 7a). In order to examine the strengths of this methodology, the risk value computed in each sector was compared with the flood damage detected through the information taken from

A New Coastal Erosion Risk Assessment Indicator: Application to the...

different sources, like newspapers, TV reports and municipal archives and then validated by field survey. The comparison between computed R values and real conditions of the damage state shows a general good correspondence. Furthermore, the computed risk values are also in good agreement with the assessment of the coast risk reported in the Plan of the Hydrological Assessment (PAI 2015) and in the Extract Plan for Coastal Erosion (Autorità di Bacino Regione Calabria 2016) of the Calabria region. Thus, the achieved results highlight that the methodology and the chosen variables provide a good evaluation of the real coastal risk condition. It should be specified that the number and the typology of variables able to establish the coastal risk assessment could be different than the ones regarded in the present work. For example, many authors suggested different approaches with diverse variables based on geological and geomorphological aspects, physical parameters, wave climate data and socioeconomic aspects (e.g., Larroudé et al. 2014; Bagdanavičiūtė et al., 2015; Denner et al. 2015; Loinenak et al. 2015; Parthasarathy and Natesan 2015; Sudha Rani et al., 2015; Semedi et al. 2016; Martínez-Graña et al., 2016; Weis et al. 2016). Usually, the choice of the type of variables is performed on the base of the investigation scale of the area. Detailed variables are used on small-scale areas where more precise results are needed (e.g., Zanuttigh et al. 2014). In Italy, the coastal studies were mainly focused on erosion processes (e.g., Caputo et al. 1989; Ietto 2001; D’Alessandro et al. 2002, 2011; Anfuso and Del Pozo 2009; Ietto et al. 2012a, 2014; Pranzini and Rossi 2014) and on coastal vulnerability based on geomorphological and wave climate features (e.g., Di Paola et al. 2013; Benassai et al. 2015; Greco and Martino 2016). The previous vulnerability assessments have been based mainly on variables constituted by computations of complex indices with data hardly available; therefore, they were tested in small and detailed areas. The approach proposed in this paper, instead, is based on data easily achievable and applicable mainly for a quick assessment of coastal risk in large areas. Probably, the conceptual approach and the typology of variables suggested for the assessment of the coastal risk may be considered too simplistic by coastal managers and stakeholders to trust the reliability of the results. However, in our opinion, there are several strength points which make the proposed methodology interesting. First, the relatively fast running time allows the user to examine many different areas covering extended coastal region. Second, the inherent uncertainty of the results, existing for all types of methodologies, can be overcome by the direct comparison between achieved results (risk values) and the real conditions of the coastal damage. Finally, it should be remarked that the methodology proposed is essentially a tool to be used in a preliminary phase for assessing risk and identifying the possible mitigation strategies in large areas. Therefore, the new methodology is not applicable to detail design processes, for which many assessment approaches, based on specific variables, have been proposed by several authors mentioned above. Considering the possible coastal defense actions, several authors observed both worldwide (Bruun 1995; Titus et al. 2009; Rosenberg et al. 2011; Brown et al. 2011; Stancheva et al., 2011) and in Italy (Cocco and Iuliano 2002; Aminti et al. 2004; Galgano 2004), as well as, in Calabria coasts (Veltri and Morosini 2002; Ietto et al. 2014) that the hard protection systems cause an increase of risks in the downcoast areas. Nowadays, the best options to protect coastal environments consist of improvement in land management that may be based on reinforcement of coastal dunes and protection of marine ecosystems; both actions are able to provide erosion control. Indeed, vegetated dunes landwards, through plantation of autochthonous species, and Posidonia oceanica meadows seawards, could reduce the wave motion and provide important natural protective mechanisms of the coastline (Koch et al. 2006; Cochard et al. 2008; Bradley and Houser 2009; Spalding et al. 2014). These actions of restoring could be pursued through a

Ietto F. et al.

process of Integrated Coastal Zone Management (ICZM) for an effective governance of coastal regions. Thus, maintaining or restoring the good ecological status of coastal ecosystems could play an important role in reducing both the high vulnerability of coastal communities and the costs associated with seaboard risks. In Calabria, the lack of a national strategy to realize an effective ICZM is, really, very restrictive, since there is a serious absence of the issue of coastal risk and its management (Cantasano 2013; Cantasano et al. 2017). Thus, the aim of the present paper is to fill this gap, developing a simple and easy-fitting methodology, suitable for micro-tidal environments, in order to establish the risk values of the whole coastal heritage. The proposed methodology expands the evaluation from geological and physical factors to biological and environmental ones. Finally, the new kind of approach could be extended to a broader context in the Mediterranean area, where similar morpho-dynamic processes occur.

5 Concluding Remarks The present paper shows a new method of coastal risk assessment, based on data easily available and, therefore, enforceable at regional-scale. The methodology is different from previous approaches established on detailed data processing, in order to evaluate risk conditions at small-scale of coastal areas. This work aims to suggest a new approach for the evaluation of coastal risks on the base of two elements: Coastal Vulnerability Assessment (CVA) and Coastal Exposure Assessment (CEA). By this way, many variables, representative of wave climate, as well as coastal and biological characteristics, were selected in order to estimate the exposure of the coast to sea energy and its sensitivity to changing processes (CVA). Furthermore, the exposure of economic, civil and environmental elements to sea-wave energy (CEA) were evaluated through other specific variables. The tested area is located in the Calabria Tyrrhenian coast (Southern Italy) between Policastro and S. Eufemia Gulfs. In this area, the achieved results enabled to recognize four levels of risk. High and very high risk level, R3 and R4 respectively, extending in 65% of the coastal belt. These conditions are mostly concentrated in the northern and central sectors of the study area, where the coastline is, mainly, characterized by narrow or absent sandy beaches heavily urbanized until backshore areas. Medium risk level (R2) is detected in the southern areas dominated by beaches with coastal dunes or high rocky coasts, which are characterized by a low urbanization state. Low risk levels (R1) are quite rare and are observed only in some limited stretches scattered along the regional seaboard. The comparison between computed risk values and the real condition of the damage state, as well as, with the coastal assessment enclosed in Calabria regional reports, shows a general and good correspondence. The observed critical condition on the Calabria Tyrrhenian coast depends mostly on the wild urbanization state and the lithological nature of the coastal stretches mainly formed by sandy beaches, as 83% of the whole coastline. Only 20% of these areas are protected by vegetated coastal dunes, which are, actually, very fragmented and restricted by human infrastructures. The suggested methodology is different from previous approaches proposed by other authors, because it is relatively easy to undertake and is based on a limited and easily detectable amount of data. In addition, the methodology here described, also considers biological and environmental characteristics of the littoral areas and other assessment criteria. The proposed procedure is suitable mainly for investigation of coastal areas at the regional-scale, because the risk analysis in more detailed areas requests the

A New Coastal Erosion Risk Assessment Indicator: Application to the...

employment of more specific variables, such as complex economic, physical and wave climate data which are hardly available. Thus, the used approach could give a worthy support to a state-run organization in order to assess at a preliminary phase the coastal risk conditions through a quick and easy methodology. Thereby, the competent authorities, supported by the information suggested by this methodology, can be able to initiate the needed processes to set aside potential funding for an appropriate mitigation action against coastal risk due to sea-waves energy. By this way, beach nourishment, reinforcement of coastal dunes, protection of marine ecosystems and/or construction of barriers could be considered as some of the possible adoptive actions. Finally, the proposed assessment approach could also be extended to coastal communities and applied to other Mediterranean littoral areas characterized by similar morpho-dynamic and urbanized conditions. Acknowledgements This research was carried out within the MIUR-ex 60% Project (Resp. F. Ietto). The authors are indebted to the three anonymous referees for their comments and useful suggestions, which were constructive and useful at improving the quality of the manuscript.

References Adger WN, Brooks N, Kelly M, Bentham S, Eriksen S (2004) New indicators of vulnerability and adaptive capacity. Tyndall Centre for Climate Change Research, technical report 7. University of East Anglia, Norwich, p 128 Alberico I, Petrosino P (2015) The hazard indices as a tool to support the territorial planning: the case study of ischia island (southern Italy). Eng Geol 197:225–239 Alberico I, Amato V, Aucelli PPC, Di Paola G, Papponem G, Rosskopf CM (2012) Historical and recent changes of the Sele River coastal plain (southern Italy): natural variations and human pressures. Rendiconti Lincei 23:3–12 Alexandrakis G, Poulos SE (2014) An holistic approach to beach erosion vulnerability assessment. Sci Rep 4:6078 Alpar B (2009) Vulnerability of Turkish coasts to accelerate sea-level rise. Geomorphology 107:58–63 Aminti PL, Cammelli C, Cappietti L, Jackson NL, Nordstrom KF, Pranzini E (2004) Evaluation of beach response to submerged groin construction at Marina di Ronchi, Italy, using a field data and a numerical simulation model. J Coast Res Spec Issue 33:99–120 Amodio ML, Bonardi G, Colonna V, Dietrich D, Giunta G, Ippolito F, Liguori V, Lorenzoni S, Paglionico A, Perrone V, Piccareta G, Russo M, Scandone P, Zanettin-Lorenzoni E, Zuppetta A (1976) L’arco CalabroPeloritano nell’orogene Appenninico Maghrebide. Memorie. Società Geologica Italiana 17:1–60 Anfuso G, Del Pozo JAM (2005) Towards management of coastal erosion problems and human structure impacts using GIS tools: case study in Ragusa Province, southern Sicily, Italy. Environ Geol 48:646–659 Anfuso G, Del Pozo JAM (2009) Assessment of coastal vulnerability through the use of GIS tools in south Sicily (Italy). Environ Manag 43:533–545 Antronico L, Borrelli L, Coscarelli L (2017) Recent damaging events on alluvial fans along a stretch of the Tyrrhenian coast of Calabria (southern Italy). Bull Eng Geol Environ 76(4):1399–1416 Autorità di Bacino Regione Calabria (2016) Piano di Bacino Stralcio per l’Erosione Costiera, Burc n. 79 del 22 Luglio 2016, pp. 1–20 Bagdanavičiūtė I, Kelpšaitė L, Soomere T (2015) Multi-criteria evaluation approach to coastal vulnerability index development in micro-tidal low-lying areas. Ocean Coast Manag 104:124–135 Barca D, Cirrincione R, De Vuono E, Fiannacca P, Ietto F, Lo Giudice A (2010) The Triassic rift system in the northern Calabrian-Peloritani Orogen: evidence from basaltic dyke magmatism in the San Donato Unit. Period Mineral 79(2):61–72 Barnett J, Adger WN (2003) Climate dangers and atoll countries. Clim Chang 61:321–337 Bellotti P, Caputo C, Davoli L, Evangelista S, Pugliese F (2009) Coastal protection in Tyrrhenian Calabria (Italy): morphological and sedimentological feedback on the vulnerable area of belvedere Marittimo. Geogr Fis Din Quat 32(1):3–14 Benassai G, Di Paola G, Aucelli PPC (2015) Coastal risk assessment of a micro-tidal littoral plain in response to sea level rise. Ocean Coast Manag 104:22–35 Bhalla R (2007) Do bio-shields affect tsunami inundation? Curr Biol 93:831–833

Ietto F. et al. Bi N, Yang Z, Wang H, Hu B, Ji Y (2010) Sediment dispersion pattern off the present Huanghe (Yellow River) subdelta and its dynamic mechanism during normal river discharge period. Estuar Coast Shelf Sci 86(3):352–362 Bittencourt ACSP, Dominguez JML, Martin L, Silva IR (2005) Longshore transport on the northeastern Brazilian coast and implications to the location of large scale accumulative and erosive zones: an overview. Mar Geol 219:219–234 Borrelli L, Coniglio S, Critelli S, La Barbera A, Gullà G (2016) Weathering grade in granitoid rocks: the San Giovanni in Fiore area (Calabria, Italy). J Maps 12(2):260–275 Bradley K, Houser C (2009) Relative velocity of seagrass blades: implications for wave attenuation in lowenergy environments. J Geophys Res 114(F1):1–13 Brown S, Barton M, Nicholls R (2011) Coastal retreat and/or advance adjacent to defences in England and Wales. J Coast Conserv 15:659–670 Bruun P (1962) Sea level rise as a cause of shore erosion. Proceeding American Society of Civil Engineers, Journal of the Waterways and Harbors Division 88:117–130 Bruun P (1995) The development of downdrift erosion. J Coast Res 11(4):1242–1257 Bryant E (2005) Natural Hazards, 2nd edn. Cambridge University Press, Cambridge C.N.R. (National Research Council) (1997) Atlante delle spiagge italiane. Tendenze evolutive - Opere umane. In: C.N.R. Progetto Finalizzato "Conservazione del suolo"- Sottoprogetto "Dinamica dei litorali". Ed. S.E.L.C.A., Firenze. Fogli: 220 Verbicaro, 228 Cetraro, 229 Paola, 236 Cosenza, 241 Nicastro. Scala 1:100.000 Cantasano N (2013) La gestione integrata delle zone costiere (GIZC): un nuovo modello di assetto territoriale. Biologi Italiani XLIII(5):31–41 Cantasano N (2017) Sedimentazione nelle praterie di Posidonia oceanica (L.) Delile lungo le coste tirreniche calabresi. Biologi Italiani XLVII(1):51–58 Cantasano N, Pellicone G, Ietto F (2017) Integrated coastal zone management in Italy: a gap between science and policy. J Coast Conserv 21:317–325 Caputo C, D'Alessandro L, La Monica GNB, Landini B, Lupia Palmieri E (1989) Evolutive dynamics and erosion condition of the italian beaches. Zeitschrift für Geomorphologie N.F., Suppl Bd 81, 31–39 Castillo ME, Baldwin EM, Casarin RS, Vanegas GP, Juaréz MA (2012) Characterization of risks in coastal zone: a review. Clean–Soil, Air, Water 40(9):894–905 Cocco E, Iuliano S (2002) Primi risultati delle ricerche sui sistemi costieri italiani (Prin 1998): casi studio lungo le coste dell’isola d’Ischia (Campania). Mem Soc Geol Ital 57:509–515 Cochard R, Ranamukhaarachi SL, Shivakoti GP, Shipin OV, Edwards PJ, Seeland KT (2008) The 2004 tsunami in Aceh and southern Thailand: a review on coastal ecosystems, wave hazards and vulnerability. Perspectives in Plant Ecolology, Evolution and Systematics 10:3–40 Cooper JAG, McKenna J (2008) Social justice and coastal erosion management: the temporal and spatial dimensions. Geoforum 39:294–306 Cooper J, McLaughlin S (1998) Contemporary multidisciplinary approaches to coastal classification and environmental risk analysis. J Coast Res 14(2):512–524 Cori B (1999) Spatial dynamics of Mediterranean coastal regions. J Coast Conserv 5:105–112 D’Alessandro F, Davoli L, Lupia Palmieri E, Raffi R (2002) Applied geomorphology: theory and practice. In: Allison RJ (ed) Natural and anthropogenic factors affecting the recent evolution of beaches in Calabria (Italy), Chichister, pp 397–427 D'Alessandro L, Davoli L, Lupia Palmieri E, Raffi R (1998) L’erosione recente delle spiagge calabresi: cause naturali e antropiche. In: Società Geologica Italiana (Ed) 79° Congresso Società Geologica Italiana, Rome, pp 373–374 D'Alessandro F, Tomasicchio GR, Frega F, Carbone M (2011) Design and management aspects of a coastal protection system. A case history in the South of Italy. Journal of Coastal Research, suppl. Special Issue SI.64, 492–495 Dawson RJ, Dickson M, Nicholls RJ, Hall J (2009) Integrated analysis of risks of coastal flooding and cliff erosion under scenarios of long term change. Clim Chang 95(1–2):249–288 Denner K, Phillips ME, Jenkins RE, Thomas T (2015) A coastal vulnerability and environmental risk assessment of Loughor estuary, South Wales. Ocean Coast Manag 116:478–490 Di Paola G, Aucelli PPC, Benassai G, Rodríguez G (2013) Coastal vulnerability to wave storms of Sele littoral plain (southern Italy). Nat Hazards 71:1795–1819 Diez PG, Perillo GME, Piccolo C (2007) Vulnerability to sea-level rise on the coast of the Buenos Aires Province. J Coast Res 23(1):119–126 Domínguez L, Anfuso G, Gracia FJ (2005) Vulnerability assessment of a retreating coast in SW Spain. Environ Geol 47:1037–1044 European Commission (2002) Towards Environmental Performance Indicators for the European Union (EU). A European system of environmental indicators. Available from http://www.e-m-a-i-l.nu/tepi/firstpub.htm. Accessed 01 March 2017 European Commission (2007) Directive 2007/60/EC of the European parliament and of the council of 23 October 2007 on the assessment and management of flood risks. Off J Eur Union 288:27–34

A New Coastal Erosion Risk Assessment Indicator: Application to the... European Commission (2008) Directive 2008/56/EC of the European Parliament and of the council of 17 June 2008 establishing a framework for community action on the field of marine environmental policy (marine strategy framework directive). Off J Eur Union 164:19–40 European Commission (2011) Joint Research Center, Technical Notes. Coastal Zones. Available from http://ies. jrc.ec.europa.eu/ Feagin RA, Smith WK, Psuty NP, Young DR, Martinez ML, Carter GA, Lucas KL, Gibeaut JC, Gemma JN, Koske RE (2010) Barrier islands: coupling anthropogenic stability with ecological sustainability. J Coast Res 26:987–992 Fonseca MS, Cahalan JA (1992) A preliminary evaluation of wave attenuation by 4 species of seagrass. Estuar Coast Shelf Sci 35:565–576 Forbes C (2009) The effects of climate change induced coastal inundation. National Environmental Law Review 4:44–57 Galgano FA (2004) Long-term effectiveness of a groin and beach fill system: a case study using shoreline change maps. J Coast Res 33:3–18 GNRAC (2006) Lo stato dei litorali in Italia. Studi Costieri 10:3–172 Gornitz V (1990) Vulnerability of the East Coast, USA to future sea level rise. J Coast Res Spec Issue 9:201–237 Gornitz VM, Daniels RC, White TM, Birdwell KR (1994) The development of a coastal risk database for the U.S. Southeast: erosion and inundation form sea level rise. Journal of Coastal Research (SI12), 327–338 Gornitz VM, Beaty TW, Daniels RC (1997) A coastal hazards data-base for the U.S. West Coast. ORNL/CDIAC81, NDP-043C. Oak ridge national laboratory, Oak ridge, Tennessee, United States of America Greco M, Martino G (2016) Vulnerability assessment for preliminary flood risk mapping and management in coastal areas. Nat Hazards 82:S7–S26 Guiducci F, Paolella G (2004) Learning from 20 years of design and realization on coastal protection over the Tyrrhenian Calabrian coast. In: 29th ICCE International Conference on Coastal Engineering. World Scientific Press (Ed), Lisbon, pp 3826–3838 Harvey N, Clouston B, Carvalho P (1999) Improving coastal vulnerability assessment methodologies for integrated coastal zone management: an approach from South Australia. Aust Geogr Stud 37(1):50–69 Hedge AV, Rejn VR (2007) Development of coastal vulnerability index for Mangalore coast, India. J Coast Res 23(5):1106–1111 Hsu JRC, Uda T, Silvester R (1993) Beaches downcoast of harbours in bays. Coast Eng 19(1–2):163–181 Hughes P, Brundrit GB (1992) An index to assess South Africa’s vulnerability to sea-level-rise. S Afr J Sci 88:308–311 Hugo G (2011) Future demographic change and its interactions with migration and climate change. Glob Environ Chang 21(Supplement 1):S21–S33 Ietto F (2001) Evoluzione delle spiagge tirreniche nord calabresi negli ultimi 50 anni. Italian Journal of Quaternary. Science 14(2):105–116 Ietto F, Le Pera E, Caracciolo L (2012a) Geomorphology and sand provenance of the Tyrrhenian coast between capo Suvero and Gizzeria (Calabria, southern Italy). Rend Online Soc Geol Ital 21:487–488 Ietto F, Parise M, Ponte M, Calcaterra D (2012b) Geotechnical characterization and landslides in the weathered granitoids of Calabria (southern Italy). Rend Online Soc Geol Ital 21:551–553 Ietto F, Le Pera E, Perri F (2013) Weathering of the ‘Rupe di Tropea’ (southern Calabria): consolidation criteria and erosion-rate estimate. Rend Online Soc Geol Ital 24:178–180 Ietto F, Cantasano N, Salvo F (2014) The quality of life conditioning with reference to the local environmental management: a pattern in Bivona country (Calabria, southern Italy). Ocean Coast Manag 102:340–349 Ietto F, Perri F, Fortunato G (2015) Lateral spreading phenomena and weathering processes from the Tropea area (Calabria, southern Italy). Environ Earth Sci 73(8):4595–4608 Ietto F, Perri F, Cella F (2016a) Geotechnical and landslide aspects in weathered granitoid rock masses (serre massif, southern Calabria, Italy). Catena 145:301–315 Ietto F, Le Pera E, Miriello D, Ruffolo SA, Perri F (2016b) Behaviour of epoxide resin used to protect the BRupe di Tropea^ (southern Calabria, Italy). Rend Online Soc Geol Ital 38:69–72 Ietto F, Perri F, Miriello D, Ruffolo SA, Laganà A, Le Pera E (2017) Epoxy resin for the slope consolidation intervention on the Tropea sandstone cliff (southern Calabria, Italy). Geoheritage. https://doi.org/10.1007 /s12371-017-0235-2 Ietto F, Perri F, Cella F (2018) Weathering characterization for landslides modeling in granitoid rock masses of the capo Vaticano promontory (Calabria, Italy). Landslides 15:43–62 IPCC (2014) Intergovernmental panel on climate change. In: Pachauri R, Meyer L (eds) Climate change 2014: synthesis report. Contribution of working groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Geneva, pp 151 ISO/IEC (2009) ISO Guide 73 Risk Management and Vocabulary. http://www.iso.org. Accessed 01 March 2017 ISPRA (2013) Annuario dei dati ambientali. Stato dell’Ambiente 47/2013. ISPRA, Rome, 31 pp. Jeftic L, Milliman JD, Sestini G (1992) Climate change and the Mediterranean. Edward Arnold (Ed), London 673 pp

Ietto F. et al. Jones RN, Boer R (2004) Assessing current climate risks. In: Adaptation policy frameworks for climate change: developing strategies, policies and measures. Lim B, Spanger-Siegfried E, Burton I, Malone E, Huq S., (Eds), Technical Paper 4, Cambridge University Press, Cambridge, pp 91–117 Koch EW, Gust G (1999) Water flow in tide- and wave-dominated beds of the seagrass Thalassia testudinum. Mar Ecol Prog Ser 184:63–72 Koch EW, Ackerman J, Verduin J, Keulen M (2006) Seagrasses: biology, ecology and conservation. In: Larkun AWD, Orth RJ, Duarte CM (eds) Fluid dynamics in seagrass ecology – from molecules to ecosystem. Springer, Netherlands, pp 193–225 La Monica GB, Landini B (1983) Proceedings of 23th Congr. Geogr. It. In: Tendenze evolutive delle coste basse della penisola italiana, Istituto di Geografia, Facoltà di Lettere e Filosofia, Università di Catania (Ed.), Catania, pp 209–217 Larroudé P, Oudart T, Daou M, Robin N, Certain R (2014) Three simple indicators of vulnerability to climate change on a Mediterranean beach: a modelling approach. Ocean Eng 76:172–182 Le Pera E, Sorriso Valvo M (2000) Weathering and morphogenesis in a Mediterranean climate, Calabria, Italy. Geomorphology 34:251–270 Lichter M, Felsenstein D (2012) Assessing the costs of sea-level rise and extreme flooding at the local level: a GIS-based approach. Ocean Coast Manag 59:47–62 Lickley MJ, Lin N, Jacoby HD (2014) Analysis of coastal protection under rising flood risk. Climate Risk Management 6:18–26 Loinenak FA, Hartoko A, Muskaananfola MR (2015) Mapping of coastal vulnerability using the coastal vulnerability index and geographic information system. Int J Technol 5:819–827 Luo S, Wang H, Cai F (2013) An integrated risk assessment of coastal erosion based on fuzzy set theory along Fujian coast, southeast chine. Ocean. Coast Manag 84:68–76 Martínez JA, Anfuso G (2008) Spatial approach to medium-term coastal evolution in south Sicily (Italy): implications for coastal erosion management. J Coast Res 24(1):33–42 Martínez-Graña AM, Boski T, Goy JL, Zazo C, Dabrio CJ (2016) Coastal flood risk management in Central Algarve: vulnerability and flood risk indices (South Portugal). Ecol Indic 71:302–316 McGranahan G, Bolk D, Anderson D (2007) The rising tide: assessing the risk of climate change and human settlements in low elevation coastal zone. Environ Urban 19:17–37 McLaughlin S, Cooper JAG (2010) A multi-scale coastal vulnerability index: a tool for coastal managers? Environmental Hazard 9(3):233–248 Medatlas Group (2004) Wind and wave atlas of the Mediterranean Sea. Western European Union, WEAO Research Cell Mokrech M, Hanson S, Nicholls RJ, Wolf J et al (2011) The Tyndall coastal simulator. J Coast Conserv 15(3): 325–335 Mura PM (1995) At the bottom of the arc: the Calabria region. In: Cortesi G (ed) Urban change and the environment. The case of north-western Mediterranean, Milan, pp 231–268 Nicholls RJ, Hoozemans FMJ (1996) The Mediterranean: vulnerability to coastal implications of climate change. Ocean Coast Manag 31(2–3):105–132 Nicholls RJ, Wong PP, Burkett VR, Codignotto JE, Hay JE, McLean RF, Ragoonaden S, Woodroffe CD (2007) Coastal systems and low-lying areas. In: Parry ML, Canziani OF, Palutikof JP, van der Linden PJ, Hansen CE (eds) Climate change 2007: impacts, adaptation and vulnerability. Contribution of working group II to the fourth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, pp 315–356 Ogniben L (1969) Schema introduttivo alla geologia del confine calabro-lucano. Mem Soc Geol Ital 8:453–763 Ozyurt G (2007) Vulnerability of coastal areas to sea level rise: a case study on Göksu Delta. Ankara, Turkey. Middle East Technical University. Master’s Thesis, 300 pp. PAI (2015) Piano di Bacino Stralcio per l’erosione costiera – Relazione di Piano. Autorità di Bacino – Regione Calabria, pp 1–36 Parry M, Canziani O, Palutikof J, van der Linden P, Hansen C (2007) Climate change 2007: impacts, adaptation and vulnerability, contribution of the working group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, pp 315–357 Parthasarathy A, Natesan U (2015) Coastal vulnerability assessment: a case study on erosion and coastal change along Tuticorin, gulf of Mannar. Nat Hazards 75:1713–1729 Pellegrino A, Prestininzi A (2007) Impact of weathering geomechanical properties of rocks along thermalmetamorphic contact belts and morpho-evolutionary processes: the deep-seated gravitational slope deformations of Mt. Granieri-Salincriti (Calabria-Italy). Geomorphology 87:176–195 Perri F, Ietto F, Le Pera E, Apollaro C (2016) Weathering processes affecting granitoid profiles of capo Vaticano (Calabria, southern Italy) based on petrographic, mineralogic and reaction path modelling approaches. Geol J 51(3):368–386

A New Coastal Erosion Risk Assessment Indicator: Application to the... Pompe JJ, Rinchart JR (2008) Mitigating damage costs from hurricane strikes along the southern-eastern US coast: a role for insurance markets. Ocean Coast Manag 51:782–788 Pranzini E, Rossi L (2014) Protocollo per il monitoraggio dell’evoluzione costiera. In: Cipriani (Ed.), Monitoraggio dell’erosione costiera - una rete di osservatori regionali, Progetto Res. Mar. pp 8–12 Quelennec R (1989) The CORINE coastal erosion project. Identification of coastal erosion problems and database on the littoral environment of eleven European countries. In: University of California (ed) Proceedings of 6th Symposium on Coastal and Ocean Management (Coastal Zone ‘89), Charleston, South Carolina, pp 4594–4601 RON (Rete Ondametrica Nazionale) (2007) In: Istituto Superiore per la Protezione e la Ricerca dell’Ambiente (ISPRA). Available at: http://www.mareografico.it/. Accessed 01/03/2017 Rosenberg DE, Kopp K, Kratsch HA, Rupp L, Johnson P, Kjelgren R (2011) Value landscape engineering: identifying coasts, water use, labor and inputs to support landscape choice. J Am Water Resour Assoc (JAWRA) 47(3):635–649 Samaras AG, Koutitas CG (2012) An integrated approach to quantify the impact of watershed management on coastal morphology. Ocean Coast Manag 69:68–77 Samaras AG, Koutitas CG (2014) The impact of watershed management on coastal morphology. A case study using an integrated approach and numerical modeling. Geomorphology 211:52–63 Sano M, Gainza J, Baum S, Choy DL, Neumann S, Tomlinson R (2015) Coastal vulnerability and progress in climate change adaptation: an Australian case study. Regional Studies in Marine Science 2:113–123 Sarma KGS (2015) Siltation and coastal erosion at shoreline harbours. In: Proceeding of the 8th International Conference on Asian and Pacific Coasts (APAC Ed). Procedia Engineering 116, 12–19 Saville T (1954) The effect of fetch width on wave generation. U.S. Army Coastal Engineering Research Centre, Tech. Memorandum No. 70, pp 10 Saye SE, van der Wal D, Pye K, Blott SJ (2005) Beach–dune morphological relationships and erosion/accretion: an investigation at five sites in England and Wales using LIDAR data. Geomorphology 72(1–4):128–155 Scandone P (1982) Structure and evolution of the Calabrian Arc. Earth Evolution Sciences 3:172–180 Semedi B, Husain BH, Hidayati N (2016) Analyzing coastal vulnerability index using integrated satellite remote sensing and geographic information system: a case study of Denpasar coastal zone. J Appl Environ Biol Sci 6(4):35–40 Small C, Nicholls RJ (2003) A global analysis of human settlement in coastal zones. J Coast Res 19:584–599 Spalding MD, Ruffo S, Lacambra C, Meliane I, Hale LZ, Shepard CC, Beck MW (2014) The role of ecosystems in coastal protection: adapting to climate change and coastal hazards. Ocean Coast Manag 90:50–57 Stancheva M, Rangel-Buitrago N, Anfuso G, Palazov A, Stanchev H, Correa I (2011) Expanding level of coastal armouring: case studies from different countries. J. Coast. Res. 1815-1819, SI 64 (Proceedings of the 11th International Coastal Symposium), Szczecin Sudha Rani NNV, Satyanarayana ANV, Bhaskaran PK (2015) Coastal vulnerability assessment studies over India: a review. Nat Hazards 77:405–428 Titus JG, Hudgens DE, Trescott DL, Craghan M, Nuckols WH, Hershner CH, Kassakian JM, Liun CJ, Merritt PG, McCue TM, O’Connell JFO, Tanski J, Wang J (2009) State and local governments plan for development of most land voluble to rising sea level along the US Atlantic coast. Environ Res Lett 4:1–7 Tran P, Shaw R (2007) Towards an integrated approach of disaster and environment management: a case study of Thua Thien Hue Province, Central Viet Nam. Environmental Hazards 7:271–282 Tsoukala VK, Katsardi V, Hadjibiros K, Moutzouris CI (2015) Beach erosion and consequential impacts due to the presence of harbours in sandy beaches in Greece and Cyprus. Environmental Processes 2(1):55–71 Uda T (2010) Japan’s beach erosion: reality and future measures. World Scientific Publishing, Singapore, 417 pp. UNISDR (2009) United Nations International Strategy for Disaster Reduction, Geneva, pp. 1–35 Vai GB (1992) Il segmento Calabro-Peloritano dell'orogene ercinico. Disaggregazione palinspastica. Boll Soc Geol Ital 111:109–129 Veltri P, Morosini AF (2002) Una procedura per la stima del rischio di erosione costiera: un caso di studio. In: Bios (Ed), 28th Convegno di Idraulica e Costruzioni idrauliche, Potenza, pp 1–10 Weis SW, Agostini VN, Roth LM, Gilmer B, Schill SR, Knowles JE, Blyther R (2016) Assessing vulnerability: an integrated approach for mapping adaptive capacity, sensitivity, and exposure. Climate Change 136:615–629 Williams AT, Davies P, Curr R, Koh A, Bodere J, Hallegouet B, Meur C, Yoni C (1993) A checklist assessment of dune vulnerability and protection in Devon and Cornwall (UK). In: Magoon OT (ed) Proceedings of 10th Symposium on Coastal and Ocean Management (Coastal Zone ‘93), American Society of Civil Engineering, New York, pp 3394–3408 Wong PP, Lee BT, Leung MHT (2006) Hot spots of population growth and urbanization in the Asia-Pacific coastal zone. In: Harvey (ed) Global change and integrated coastal management. Springer, Dordrecht, pp 161–193 Zanuttigh B, Simcic D, Bagli S, Bozzeda F, Pietrantoni L, Zagonari F, Hoggart S, Nicholls RJ (2014) THESEUS decision support system for coastal risk management. Coast Eng 87:218–239