A Methodological Approach to Determine Sound Response Modalities to Coastal Erosion Processes in Mediterranean Andalusia (Spain)

Human occupation along coastal areas has been greatly increasing in recent decades and, in many places, human activities and infrastructures are threatened by erosion processes that can produce relevant economic and human losses. In order to reduce such impacts and design sound management strategies, which can range from the "no action" to the "protection" option, coastal managers need to know the intrinsic coastal sensitivity and the potential vulnerability and value of land uses. In this paper, in a first step, coastal sensitivity was determined by calculating the following: (i) the spatial distribution at the coast of the wave forcing obtained by using the ERA5 wave dataset and defined as the energy associated with the 50-year return period storm. Two storm conditions were considered, that is, one for the eastern and one for the western parts of the Andalusia Mediterranean coast, respectively, characterized by a height of 8.64-7.86 m and 4.85-4.68 m and (ii) the existence of a buffer zone, namely the dry beach width expressed as a multiple of the 20-year predicted shoreline position that was calculated using a dataset of aerial photographs covering a time span from 1956 to 2016. Coastal sensitivity values were divided into five classes with class 1 indicating the lowest sensitivity (i.e., the presence of a wide buffer zone associated with low wave energy flux values) and class 5 the highest sensitivity (i.e., a narrow buffer zone associated with very high wave energy flux values). In a second step, land uses were obtained from the official Land Use Map of the Andalusia Region, based on the results of the "Coordination of Information on the Environment" (CORINE) European Project. Such uses were divided into five classes from class 1 including natural areas (typologies "A" and "B" of the CORINE Project) to class 5 including very capital land uses (typologies "E1" and "E2"). In a third step, information concerning coastal sensitivity and land uses was crossed to determine the best mitigation strategies to cope with erosion processes. The "no action" option was observed at the westernmost area of Cadiz Province and at some areas from the west coast of Almeria Province, where both coastal sensitivity and land use classes show low values; the "adaptation" option was recorded along more than one half of the coast studied, essentially at natural areas with high sensitivity and at urbanized areas with low sensitivity; and the "protection" option was observed especially at some areas from the center and eastern part of Malaga Province and at the easternmost areas of Almeria Province, where both coastal sensitivity and land use classes presented high values

Experiencias en gestión de la erosión costera en Italia: casos prácticos de Sicilia y Toscana

El trabajo presenta los resultados de diferentes estudios llevados a cabo mediante fotos aéreas y mapas de diferentes escalas y años en Sicilia y en Toscana (Italia). En detalle, se describen los procesos de erosiónJacreción observados y las intervenciones llevadas a cabo para contrarrestarlos. Finalmente se analiza la evolución de las técnicas de defensa costera empleadas en las últimas décadas en Italia, resaltando el cambio de tendencia observado, es decir el remplazo de las obras de protección rígidas por obras de regeneraciónThe paper deals with the results of several works carried out in Sicily and Tuscany (Italy) by the means of aerial photographs and maps of different years and scales. In detail, it describes the erosion/accretion problems as well as the solutions adopted to solve them. Further, it is analyzed the evolution of defense techniques used in Italy in last decades, in order to highlight the change of trend recoded, that is the replacement of hard solutions by new, soft solutions, e.g. beach nourishment

An Integrated Coastal Sediment Management Plan: The Example of the Tuscany Region (Italy)

This paper presents the results of a study carried out to support the Region of Tuscany Coastal Sediment Management Plan, with the main aim of establishing the sediment budget considering the time span from 1981-1985 to 2005 for the 56 coastal sectors into which the 215 km-long continental sandy coast of Tuscany (Italy) was divided. The sand stability (according to a stability index) and colour compatibility (according to the CIEL*a*b* colour space with an acceptability range conforming to national guidelines) were determined in order to assess the possibility of using the available sediment in accreting sectors to nourish the beach in eroding areas. Only in two cases-i.e., the updrift of a harbour (at Viareggio) and in a convergence zone (at Marina di Pietrasanta)-are the volumes of sufficient magnitude to support a large nourishment project; however, the mean sand size is too small to guarantee efficient nourishment, even with medium-term stability. In contrast, the colour difference, in most of the cases, was shown to be acceptable. Other small sediment stocks, suitable for colour but not for grain size, can be used for periodic ephemeral nourishment works to support seasonal tourist activities. The limited resources available make it necessary to adopt a plan for their optimal use from a regional perspective. This kind of study is of great interest for the proposal of sound management actions to counteract the increasing erosion processes linked to climate change phenomena and human effects on rivers and coastal systems

Coastal Dynamic and Evolution: Case Studies from Different Sites around theWorld

In recent decades, coastal areas have experienced a progressive increase in erosion and flooding processes as a consequence of the combined effect of natural factors and strong human pressures. These processes are particularly evident on low-lying areas and are expected to be exacerbated by the ongoing climate change, which will impact the littorals both in the short term, by affecting the duration and frequency of storms, and in the long term, by inducing variation in the sea-level position. In this context, this Special Issue is devoted to collecting geomorphological studies on coastal dynamic and evolution by means of multidisciplinary research methodologies and investigations, which represent a very useful set of information for supporting the integrated management of coastal zone. The volume includes 14 papers addressing three main topics (i) shoreline characterization, dynamic and evaluation; (ii) coastal hazard evaluation and impact assessment of marine events; and (iii) relevance of sediment collection and analysis for beach nourishment. Case studies from Russia, Italy, California (USA), Morocco, Spain, Indonesia, Ireland and Colombia are shown in the Special Issue, giving to the reader a wide overview of coastal settings and methodological approaches

Climate Change and the Mediterranean Southern Coasts

This chapter deals with climate change effects in the Mediterranean littoral of Morocco, which is one of the most vulnerable countries within the Mediterranean region, especially the low-lying areas located in the eastern, i.e., Nador and Saidia areas, and western parts, i.e., Tangier and Tetouan areas. The different aspects of climatic change characteristics and impacts are also analysed, including: sea level rise (SLR) trend in the Mediterranean littoral of Morocco; coastal erosion and flooding hazards; water management problems; and agricultural and tourist activities. It is established that appropriate vulnerability assessment and adaptation strategies to SLR and climate change are required at regional and national scale in Morocco, to improve the tools for correct coastal zone management

Dune Systems' Characterization and Evolution in the Andalusia Mediterranean Coast (Spain)

This paper deals with the characterization and evolution of dune systems along the Mediterranean coast of Andalusia, in the South of Spain, a first step to assess their relevant value in coastal flood protection and in the determination of sound management strategies to protect such valuable ecological systems. Different dune types were mapped as well as dune toe position and fragmentation, which favors dune sensitivity to storms' impacts, and human occupation and evolution from 1977 to 2001 and from 2001 to 2016. Within a GIS (Geographic Information System) project, 53 dune systems were mapped that summed a total length of ca. 106 km in 1977, differentiating three dune environments: (i) Embryo and mobile dunes (Type I), (ii) grass-fixed dunes (Type II) and (iii) stabilized dunes (Type III). A general decrease in dunes' surfaces was recorded in the 1977-2001 period (-7.5 x 10(6)m(2)), especially in Malaga and Almeria provinces, and linked to dunes' fragmentation and the increase of anthropic occupation (+2.3 x 10(6)m(2)). During the 2001-2016 period, smaller changes in the level of fragmentation and in dunes' surfaces were observed. An increase of dunes' surfaces was only observed on stable or accreting beaches, both in natural and anthropic areas (usually updrift of ports)

Coastal vulnerability in the Mediterranean sector between Fnideq and M’diq (North of Morocco)

This study assessed coastal vulnerability to erosion processes along a 24- km-long littoral with different levels of human occupation. An aerial photogram- metric flight and a Quickbird satellite image were used for mapping land uses and reconstructing coastal evolution from 1986 to 2003. Maximum erosion (- 2.48 myr−1) was recorded south of Marina Kabila port and maximum accretion (+2.25 myr−1) south of Marina Smir port. Erosion/accretion rates have been divided into five categories and land uses have been mapped and divided into three categories. Coastal vulnerability has been assessed by combining coastal trend with land-use categories: 10% of the littoral recorded “very high” vulner- ability, 29% recorded “high” vulnerability, and 61% of the investigated littoral presented “null” and “low” vulnerability. The “Imminent Collapse Zone”, i.e. the littoral zone threatened by imminent erosion, presented mean values of 10.34 m, with maximum and minimum values of 15.3 and 7.6 m, respectively. Several human structures and activities are located within the imminent collapse zone and consequently will be threatened by severe erosion in near future

The Mediterranean Coast of Andalusia (Spain): Medium-Term Evolution and Impacts of Coastal Structures

This paper shows coastal evolution along the Andalusia Region (Spain) and the impacts on it of coastal structures. The study area was divided into 47 units to calculate the erosion/accretion/stability (or evolution) rates by using the DSAS extension of ArcGIS software. Evolution rates were divided into different classes from “Very high accretion” to “Very high erosion”. As a result, 9 units recorded accretion, 19 stability and 19 erosion. Further, 17 units presented a positive balance and 28 units a negative one, showing a negative net balance of 29,738.4 m2/year corresponding to the loss of 1784.30 km2 of beach surface in the 1956–2016 period. The distribution of evolution areas along the studied coast was carried out by means of the “R” project for statistical computing. The analysis evidenced the impact of rigid structures: accretion was essentially observed up-drift of ports and groins and in correspondence of protection structures, especially of breakwaters. Erosion classes were observed down-drift of ports and groins and in correspondence of revetments/seawalls, and at largest river deltas, and “stability” was observed at pocket beaches and coastal areas locally stabilized by protection structures. Last, results were used to determine the distribution of swash- and drift-aligned coastal sectors and main direction of sedimentary transport

Coastal vulnerability in the Mediterranean sector between Fnideq and M'diq (North of Morocco)

This study assessed coastal vulnerability to erosion processes along a 24-km-long littoral with different levels of human occupation. An aerial photogram-metric flight and a Quickbird satellite image were used for mapping land uses and reconstructing coastal evolution from 1986 to 2003. Maximum erosion (-2.48 myr-1) was recorded south of Marina Kabila port and maximum accretion (+2.25 myr-1) south of Marina Smir port. Erosion/accretion rates have been divided into five categories and land uses have been mapped and divided into three categories. Coastal vulnerability has been assessed by combining coastal trend with land-use categories: 10% of the littoral recorded >very high> vulner-ability, 29% recorded >high> vulnerability, and 61% of the investigated littoral presented >null> and >low> vulnerability. The >Imminent Collapse Zone>, i.e. the littoral zone threatened by imminent erosion, presented mean values of 10.34 m, with maximum and minimum values of 15.3 and 7.6 m, respectively. Several human structures and activities are located within the imminent collapse zone and consequently will be threatened by severe erosion in near future.This work is a contribution to the Morocco PROTARS III D16/07 Research Project, the French-Moroccan MA/06/159 Volubilis Program and the Andalusia research Group RNM-328.Peer Reviewe