A Web GIS Decision Support System For Coastal Risk Assessment and Mitigation Planning

Coastal flooding poses serious threats to coastal areas around the world, billions of dollars in damage to property and infrastructure, and threatens the lives of millions of people. Therefore, disaster management and risk assessment aims at detecting vulnerability and capacities in order to reduce coastal flood disaster risk. In particular, non-specialized researchers, emergency management personnel, and land use planners require an accurate, inexpensive method to determine and map risk associated with storm surge events and long-term sea level rise associated with climate change. This study contributes to the spatially evaluation and mapping of social-economic-environmental vulnerability and risk at sub-national scale through the development of appropriate tools and methods successfully embedded in a Web-GIS Decision Support System. A new set of raster-based models were studied and developed in order to be easily implemented in the Web-GIS framework with the purpose to quickly assess and map flood hazards characteristics, damage and vulnerability in a Multi-criteria approach. The Web-GIS DSS is developed recurring to open source software and programming language and its main peculiarity is to be available and usable by coastal managers and land use planners without requiring high scientific background in hydraulic engineering. The effectiveness of the system in the coastal risk assessment is evaluated trough its application to a real case study.

Dynamics of coastal aquifers: data-driven forecasting and risk analysis

This work is focused on the study of saltwater intrusion in coastal aquifers, and in particular on the realization of conceptual schemes to evaluate the risk associated with it. Saltwater intrusion depends on different natural and anthropic factors, both presenting a strong aleatory behaviour, that should be considered for an optimal management of the territory and water resources. Given the uncertainty of problem parameters, the risk associated with salinization needs to be cast in a probabilistic framework. On the basis of a widely adopted sharp interface formulation, key hydrogeological problem parameters are modeled as random variables, and global sensitivity analysis is used to determine their influence on the position of saltwater interface. The analyses presented in this work rely on an efficient model reduction technique, based on Polynomial Chaos Expansion, able to combine the best description of the model without great computational burden. When the assumptions of classical analytical models are not respected, and this occurs several times in the applications to real cases of study, as in the area analyzed in the present work, one can adopt data-driven techniques, based on the analysis of the data characterizing the system under study. It follows that a model can be defined on the basis of connections between the system state variables, with only a limited number of assumptions about the "physical" behaviour of the system.

Stratigraphic study and analysis of the barchan dunefield of the Laguna coastal zone in Santa Catarina, Brazil

The association of several favorable factors has resulted in the development of a wide barchan dune field that stands out as a fundamental element in the coastal landscape of southern Santa Catarina state in Brazil. This original ecosystem is being destroyed and highly modified, due to urbanization. This work identifies and discusses its basic characteristics and analyzes the favorable factors for its preservation, in the foreseen of both a sustainable future and potential incomes from ecotourism. The knowledge of the geologic evolution allows to associate this transgressive Holocene dunes formation to more dissipative beach conditions. Spatial differences on morphodynamics are related to local and regional contrasts in the sediment budget, with an influence on gradients of wave attenuation in the inner shelf and consequently with influence in the level of coastal erosion. The link between relative sea level changes and coastal eolian sedimentation can be used to integrate coastal eolian systems to the sequence stratigraphy model. The main accumulation phase of eolian sediments would occur during the final transgressive and highstand systems tracts. Considering the global character of Quaternary relative sea level changes, the Laguna transgressive dune field should be correlated with similar eolian deposits developed along other parts of the Brazilian coast compatibles with the model of dunefield initiation during rising and highstand sea level phases.

Zur Karbonatsedimentologie, Biofazies und sequenzstratigraphischen Architektur eines fossilen Hochenergie-Schelfs aus dem Neogen der Algarve (Miozän, Südportugal)

Die neogene Lagos-Portimão Formation (Unter- bis Mittelmiozän) bildet einen Teil der Steilküste der Algarve (S-Portugal) und besteht aus einer zyklischen Wechsellagerung von Karbonaten und Sand-steinen. Die vorliegende Arbeit bietet ein Modell zur sedimentologischen, faziellen und stratigraphischen Entwicklung dieser Einheit an. Basierend auf Profilen entlang der gesamten lateralen Erstreckung der Einheit wurden verschiedene Gelände- und Labormethoden angewandt, um ein Modell entwickeln zu können. Messungen des Sr87/86-Isotopenverhältnisses sollten Klarheit bezüglich der stratigraphischen Position bringen. Die laterale Korrelation der Profile erfolgte über lithologische und fazielle Ansprachen. Unterstützend wurden einzelne Profile mit einem tragbaren Gammaray-Spektrometer gemessen. Es wurden vier Leithorizonte etabliert, die sich durch fazielle Merkmale und spezielle Fossilführung defi-nieren lassen. Die Mikrofazies wurde qualitativ und quantitativ analysiert. Als statistisches Verfahren wurde unter anderem eine hierarchische Clusteranalyse durchgeführt, über welche fünf Biofaziestypen des warm-temperierten Klimabereichs unterschieden werden. Die Fossilführung wird von Mollusken, Bryozoen und Rotalgen dominiert. Ausnahmen bilden stratigraphisch isolierte Vorkommen von kolo-nialen Korallen, die jedoch keine Riffkörper aufbauen. Die Ergebnisse aller zuvor erwähnten Untersuchungen deuten auf Ablagerungen eines nicht-tropischen Hochenergie-Schelfs hin. Sedimentäre Zyklen sind oftmals unvollständig, es treten Hartgründe und Auf-arbeitungs- bzw- Kondesationshorizonte auf. Die geochemische Altersdatierung weist Alterssprünge und -inversionen auf. Ein Vergleich mit dem SW-australischen Schelf und dem von James et al. (1994) eingeführten Modell des shaved shelf bietet sich aufgrund der Ähnlichkeit der Sedimentgesteine und des ozeanographischen Settings an. Weiterhin werden zeitgleiche bzw. faziell ähnliche Becken vergleichend diskutiert. Das Sedimentationsgeschehen der Lagos-Portimão Formation wird maßgeblich durch eine halokinetisch bedingte unregelmäßige Subsidenz und Hebung beeinflußt. Der Salzdom von Albufeira war während der Sedimentation der Einheit mehrfach in Bewegung. Rutschungspakete, Entlastungsspalten und Sanddikes zeugen davon. Die sequenzstratigraphische Interpretation bietet einen neuen Ansatz, in dem sie von Hochstand-Sandsteinen und Tiefstand-Karbonaten ausgeht.

Citizen science as a tool for the environmental quality assessment of the Mediterranean coastal habitats

The growing need to assess the environmental status of the Mediterranean coastal marine habitats and the large availability of data collected by Reef Check Italia onlus (RCI) volunteers suggest the possibility to develop innovative and reliable indices that may support decision makers in applying conservation strategies. The aims of this study were to check the reliability of data collected by RCI volunteers, analyse the spatial and temporal distribution of RCI available data, resume the knowledge on the biology and ecology of the monitored species, and develop innovative indices to asses the ecological quality of Mediterranean subtidal rocky shores and coralligenous habitats. Subtidal rocky shores and coralligenous were chosen because these are the habitats more attractive for divers; therefore mlst data are referring to them, moreover subtidal rocky bottom are strongly affected by coastal urbanisation, land use, fishing and tourist activities, that increase pollution, turbidity and sedimentation. Non-indigenous species (NIS) have been recognized as a major threat to the integrity of Mediterranean native communities because of their proliferation, spread and impact on resident communities. Monitoring of NIS’ spreading dynamics at the basin spatial scale is difficult but urgent. According to a field test, the training provided by RCI appears adequate to obtain reliable data by volunteers. Based on data collected by RCI volunteers, three main categories of indices were developed: indices based on species diversity, indices on the occurrence non-indigenous species, and indices on species sensitive toward physical, chemical and biological disturbances. As case studies, indices were applied to stretches of coastline defined according to management criteria (province territories and marine protected areas). The assessments of ecological quality in the Tavolara Marine Protected Area using the species sensitivities index were consisten with those previously obtained with traditional methods.

Polychaete fauna of the Northwest Portuguese Coastal Shelf: ecology, diversity and distribution

Polychaetes are one of the larger groups of macroinvertebrates with more than 9000 species recognised, distributed worldwide. Thanks to the broad ecological adaptability and high abundaces, this taxon plays a leading role and is considered an important component of all benthic assemblages. Our knowledge about the West Iberian Coast polychaete fauna are scarce, and the only studies are recent. In this sense, the aim of this work was to investigate the composition and the spatial distribution of the polychaete fauna along the NW Portuguese Coastal Shelf, focusing on their relationship to environmental factors (depth, grain size, longitude and latitude) and to add new data to the existing biological dataset. A total of 39 sites were analysed, collected in an area of about 5665 km², between 20 and 150 m depth, distributed in a way to cover the overall grain size gradient. A total of 9352 specimens belonging to 41 families were found, and the analysis based on the abundance of polychaete species revealed five affinity groups: (a) nearshore medium sand characterised by Pisione parapari and Hesionura elongata; (b) very coarse sand that showed the highest abundance of Syllidae and was characterised by Protodorvillea kefersteini and Syllis garciai; (c) fine sand dominated by Spiophanes bombyx and Glycera tridactyla; (d) very fine sand with Nepthys assimilis and Amage sp. and the highest abundance of Paraonidae; (d) mud characterised by Labioleanira yhleni and Ampharete finmarchica. The combination of the environmental variables and the biological data, done with BIOENV routine, demonstrated that depth, grain size and fine contents were the best related with the biological data (rho=0.598). In general, the results agree with the composition and the spatial distribution of the polychaete fauna in other parts of the world; further polychaete assemblages related to mud sediments were firstly recorded in the Northwestern Portuguese Coastal Shelf.

Characterisation of extreme winter precipitation in Mediterranean coastal sites and associated anomalous atmospheric circulation patterns

We present an analysis of daily extreme precipitation events for the extended winter season (October–March) at 20 Mediterranean coastal sites covering the period 1950–2006. The heavy tailed behaviour of precipitation extremes and estimated return levels, including associated uncertainties, are derived applying a procedure based on the Generalized Pareto Distribution, in combination with recently developed methods. Precipitation extremes have an important contribution to make seasonal totals (approximately 60% for all series). Three stations (one in the western Mediterranean and the others in the eastern basin) have a 5-year return level above 100 mm, while the lowest value (estimated for two Italian series) is equal to 58 mm. As for the 50-year return level, an Italian station (Genoa) has the highest value of 264 mm, while the other values range from 82 to 200 mm. Furthermore, six series (from stations located in France, Italy, Greece, and Cyprus) show a significant negative tendency in the probability of observing an extreme event. The relationship between extreme precipitation events and the large scale atmospheric circulation at the upper, mid and low troposphere is investigated by using NCEP/NCAR reanalysis data. A 2-step classification procedure identifies three significant anomaly patterns both for the western-central and eastern part of the Mediterranean basin. In the western Mediterranean, the anomalous southwesterly surface to mid-tropospheric flow is connected with enhanced moisture transport from the Atlantic. During ≥5-year return level events, the subtropical jet stream axis is aligned with the African coastline and interacts with the eddy-driven jet stream. This is connected with enhanced large scale ascending motions, instability and leads to the development of severe precipitation events. For the eastern Mediterranean extreme precipitation events, the identified anomaly patterns suggest warm air advection connected with anomalous ascent motions and an increase of the low- to mid-tropospheric moisture. Furthermore, the jet stream position (during ≥5-year return level events) supports the eastern basin being in a divergence area, where ascent motions are favoured. Our results contribute to an improved understanding of daily precipitation extremes in the cold season and associated large scale atmospheric features.

Deglaciation records of 17O-excess in East Antarctica: reliable reconstruction of oceanic relative humidity from coastal sites

We measured δ17O and δ18O in two Antarctic ice cores at EPICA Dome C (EDC) and TALDICE (TD), respectively and computed 17O-excess with respect to VSMOW. The comparison of our 17O-excess data with the previous record obtained at Vostok (Landais et al., 2008) revealed differences up to 35 ppm in 17O-excess mean level and evolution for the three sites. Our data showed that the large increase depicted at Vostok (20 ppm) during the last deglaciation, is a regional and not a general pattern in the temporal distribution of 17O-excess in East Antarctica. The EDC data display an increase of 13 ppm, whereas the TD data show no significant variation from the Last Glacial Maximum (LGM) to the Early Holocene (EH). Lagrangian moisture source diagnostic revealed very different source regions for Vostok and EDC compared to TD. These findings combined with the results of a sensitivity analysis, using a Rayleigh-type isotopic model, suggest that relative humidity (RH) at the oceanic source region (OSR) are a determining factor for the spatial differences of 17O-excess in East Antarctica. However, 17O-excess in remote sites of continental Antarctica (e.g. Vostok) may be highly sensitive to local effects. Hence, we consider 17O-excess in coastal East Antarctic ice cores (TD) to be more reliable as a proxy for RH at the OSR.