During the last decade, several papers have been published to estimate the relative sea level change from coastal archaeological indicators of the last 3.4 ka BP in many locations of the Italian coasts and the Mediterranean Sea. The use of the archaeological information has been poorly focused for the Middle Ages, due to the few available coastal installations for this period, thus not allowing precise sea level estimation for the last 1000 years, to complement the instrumental data available for the last 100e120 years. This study discusses an archaeological marker of the Middle Ages, used to reconstruct the story of the sea level changes in the last 1000 years, at the St. Nicholas Basilica, built in 1087 AD along the coast of Bari (Apulia, southern Italy). The elevations of the ancient floor levels of the crypt underwent repeated flooding due to a continuous rising of the groundwater table, which required restoration and uplifting of pavements between 1087 and 1956 to keep them dry. The palaeo-sea levels have been obtained by measuring the position of the groundwater table, the elevation of which is mainly driven by sea level since the time of the construction of the Basilica. The elevation of the archaeological markers and the water table were compared against the latest predicted sea level curve for the Holocene along the coast of Bari. As this coastal area is unaffected by significant vertical tectonic motion over the last 125 ky, the data detail the timing of the relative sea level rise since the Middle Ages and can be used to improve the predicted sea level curve for this region for the last 1000 years.

Recent international researches have underlined the evidences of climate changes throughout the world. Among the consequences of climate change, there is the increase in the frequency and magnitude of natural disasters, such as droughts, windstorms, heat waves, landslides, floods and secondary floods (i.e. rapid accumulation or pounding of surface water with very low flow velocity). The Damaging Hydrogeological Events (DHEs) can be defined as the occurrence of one or more simultaneous aforementioned phenomena causing damages. They represent a serious problem, especially in DHE-prone areas with growing urbanisation. In these areas the increasing frequency of extreme hydrological events could be related to climate variations and/or urban development. The historical analysis of DHEs can support decision making and land-use planning, ultimately reducing natural risks. The paper proposes a methodology, based on both historical and time series approaches, used for describing the influence of climatic variability on the number of phenomena observed. The historical approach is finalised to collect phenomenon historical data. The historical flood and landslide data are important for the comprehension of the evolution of a study area and for the estimation of risk scenarios as a basis for civil protection purposes. Phenomenon historical data is useful for expanding the historical period of investigation in order to assess the occurrence trend of DHEs. The time series approach includes the collection and the statistical analysis of climatic and rainfall data (monthly rainfall, wet days, rainfall intensity, and temperature data together with the annual maximum of short-duration rainfall data, from 1 hour to 5 days), which are also used as a proxy for floods and landslides. The climatic and rainfall data are useful to characterise the climate variations and trends and to roughly assess the effects of these trends on river discharge and on the triggering of landslides. The time series approach is completed by tools to analyse simultaneously all data types. The methodology was tested considering a selected Italian region (Apulia, southern Italy). The data were collected in two databases_ a damaging hydrogeological event database (1186 landslides and floods since 1918) and a climate database (from 1877; short-duration rainfall from 1921). A statistically significant decreasing trend of rainfall intensity and an increasing trend of temperature, landslides, and DHEs were observed. A generalised decreasing trend of short-duration rainfall was observed. If there is not an evident relationship between climate variability and the variability of DHE occurrences, the role of anthropogenic modifications (increasing use or misuse of flood- and landslide-prone areas) could be hypothesized to justify the increasing occurrences of floods and landslides.. This study identifies the advantages of a simplifying approach to reduce the intrinsic complexities of the spatial-temporal analysis of climate variability, permitting the simultaneous analysis of the modification of flood and landslide occurrences.

The main purpose of the research is to define management apporouches for a coastal karstic aquifer. The core of the tools uses numerical modelling, applied to groundwater resource of Salento (southern Italy) and criteria to reduce the quantitative and qualitative degradation risks. The computer codes selected for numerical groundwater modelling were MODFLOW and SEAWAT. The approach chosen was based on the concept of a equivalent homogeneous porous medium by which it is assumed that the real heterogeneous aquifer can be simulated as homogeneous porous media within cells or elements. The modelled aquifer portion extends for 2230 km2, and it was uniformly discretized into 97,200 cells, each one of 0.6 km2. Vertically, to allow a good lithological and hydrogeological discretization, the area was divided into 12 layers, from 214 to -350 m asl. Thickness and geometry of layers was defined on the basis of the aquifer conceptualisation based on the 3d knowledge of hydrogeological complexes. For the boundary conditions, inactive cells were used along the boundary with the rest of Murgia-Salento aquifer, as conceptual underground watershed due to the absence of flow. About the sea boundary was used CHD boundary cells (Constant Head Boundary). Additional boundary conditions were used for SEAWAT modelling, as initial concentration and constant concentration, in the latter case for cells shaping the coastline. A mean annual net rainfall (recharge) was calculated in each cell with a GIS elaboration, ranged from 68 to 343 mm, 173 mm an average. The recharge or infiltration was calculated using an infiltration coefficient (IC) (defined as infiltration/net rainfall ratio) for each hydrogeological complex, assuming values equal to 1 inside endorheic areas. The mean annual recharge was equal to 150 mm. The model was implemented using MODFLOW and SEAWAT codes in steady-state conditions to obtain a starting point for following transient scenarios, using piezometric data of thirties as in that period the discharge level was negligeable. The model was calibrated through the use of PEST (Non-Linear Parameter Estimation) code, a standard in the geo-environmental modelling. The calibration was realised using data of 17 selected wells. The results of calibration can be summarised considering these control parameters_ the correlation coefficient, equal to 0.92, the standard deviation, equal to 0.7, the mean square error, equal about to 0.65, and the absolute mean residue (RMS), equal to 12%. The result emphasize the intrusion phenomena of seawater into aquifer with a important reduction of the quality of water and shown the importance of define management policies of groundwater extraction.

All natural waters contain dissolved minerals from interactions with atmospheric and soil gases, mixing with other solutions, and/or interactions with the biosphere and lithosphere. In many cases, these processes result in natural waters containing solute or salinity above concentrations recommended for a specified use, which creates significant social and economic problems. Groundwater salinisation can be caused by natural phenomena and anthropogenic activities. For the former case, we can distinguish terrestrial and marine phenomena. Approximately 16% of the total area of continental earth is potentially involved in groundwater salinisation. Seawater intrusion can be considered to be the primary phenomenon to be studied in terms of groundwater salinisation. Three schematic approaches to the protection of groundwater via salinisation mitigation and/or groundwater salinity improvement are described based on the classifications of the primary salinisation sources and focusing on the effect of seawater intrusion. The complexity of these approaches generally increases due to difficulties caused by groundwater quality and quantity degradation and increased demand for quality water. In order from the lowest to the highest complexity, these approaches are the engineering approach, the discharge management approach, and the water and land management approach. The engineering approach is realised on the local or detailed scale with the purpose of controlling the salinisation, optimising the well discharge with specific technical solutions and/or completing works to improve the quality and/or quantity of the discharged fresh groundwater. The discharge management approach encompasses at least an entire coastal aquifer and defines rules concerning groundwater utilisation and well discharge. The water and land management approach should be applied on the regional scale. Briefly, this approach becomes necessary when one or more need creates an overall framework of high-quality water scarcity. These conditions, sometimes combined with an awareness of negative environmental effects, force people to accept new water saving practices and land use modifications. As the natural effects of salinisation can be enhanced by a multiplicity of human actions, the discharge management approach and the water and land management approach should generally be applied by water authorities or institutional and governmental organisations that are responsible for groundwater quality and availability. The practical study of Apulian karstic coastal aquifers is discussed in detail. Previously experienced management difficulties are described, as well as a proposed multi-methodological approach based on monitoring networks, the spatiotemporal analysis of groundwater quality changes, and multiparameter well logging. The core of this approach is the definition of the salinity threshold value between pure fresh groundwater and any fresh and saline groundwater mixture. The basic or single tools were defined to be simple, quick and cost-effective to be applicable to the widest range of situations.