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The spatio-temporal evolution of groundwater chemistry has seen an increase in interest over the last decade at a global level. Identifying and discerning the sources of the natural and anthropogenic compounds and the actual hydrochemical processes, as well as their evolution, is essential to support a sustainable planning for managing and protecting groundwater resources at the present time and in the future. The main objective of this study is the comparison of two study areas in Italy (Piedmont and Campania Regions), different in their geographical and geological contexts and climate conditions, to highlight the similarities and differences in the hydrogeochemical behavior in space and time. Three main ions were considered (NO3 –, SO4 2–, Na+) and analyzed to identify the sources and hydrochemical processes responsible for their spatial distribution in the 2015-2020 period and evaluate the existence and the potential causes of trends in their concentration for the 2000-2020 period. Results highlight specific factors and processes distinguishing the spatial distribution and temporal variability of ion concentrations in Piedmont and Campania study areas. These processes are mainly related to the geological and geographical features of the study areas. In both areas, a significant influence of anthropogenic pressures emerges for both spatial and temporal evolutions, with remarkably increasing trends in NO3 – concentrations. In conclusion, some factors and processes emerge as site-specific, mainly related to the geological aspects and natural hydrochemical processes, whereas others are in common (i.e., anthropogenic impacts); thus, reinforcing the advantage of making comparative studies.

Come di consueto il mese di settembre è stato ricco di eventi organizzati o co-organizzati da IAH Italia. [Article in Italian]

[In Italian]

The analysis of the time-series of groundwater level are extremely important to observe the behaviours of groundwater over time and to identify any critical situations. The studied area is an agricultural district characterised by paddy fields, located in the eastern part of Piedmont, on the border with Lombardy. In this area long time-series of groundwater level, starting from the 1960s, have been collected in 16 wells. Water table data have a good completeness (in the majority of the cases >90%). Firstly, the groundwater hydrodynamic behaviour, based on water table levels, was investigated to highlight the response of groundwater to the recharge. A basic statistical analysis was performed (mean, median, standard deviation, maximum, minima), and then trends of water table levels were evaluated in order to better observe the long-term behaviour of groundwater. These analyses allowed to observe a groundwater hydrodynamic behaviour characterised by a repeating annual pattern (minimum in February/March and maximum in August/September) in correspondence to the period of irrigation. Moreover, trend analysis highlighted the presence of both wells with a decreasing water table (with maximum lowering of 4.3 m in 60 years) and wells with an increasing water table (with maximum rises of 2.8 m in 35 years). Furthermore, in most cases, it can be observed that all three trends analysed agree on being positive or negative. Future insights will be the comparison of these long time-series with the meteorological data, and the investigation of other factors (e.g. anthropic withdrawal, variations of cultivation practices and irrigation, geology of the subsoil) to better understand the causes of the water table fluctuations and trends.

Not available [In Italian]

[Article in Italian]

The Hodh el Chargui, a region located in the south-east of the Mauritania at 1000 km to the capital city of Nouakchott, is one of the poorer and remoter areas of the country. It is characterised by hard and in rural environment. Farmers and agro-pastoralists are the main economic actors and completely depend on natural resources. A specific project entitled “Reducing Agro-pastoral Vulnerability and Improving Resilience in Hodh el Chargui”, funded by European Union, has been implemented in the Program “Institutional Strengthening in Mauritania towards Agricultural and Pastoral Resilience (RIMRAP)”. The aims of the project are the strengthening of the resilience of Hodh el Chargui communities and the reduction of their vulnerability to crisis, assuring access to natural resources and their sustainable use. In particular, the water resource is fundamental to assure the development of the traditional agricultural and pastoral activities and guarantee proper health conditions. The present study reports the results obtained from a census of the well in the Hodh el Chargui, their distribution in the region and the main features of groundwater resource.

Tracer tests were utilised in an area of northwester Italy, in order to evaluate the hydrogeological relationship between the drinking water Montellina Spring and the Renanchio Stream, likely feeding the spring. The project of a derivation from the stream for an hydroelectric plant could affect the water regime of the spring. So an analytical assessment of the connection existing between the stream and the spring was required. Moreover, a geological survey of the spring area was carried out, with the aim to reconstruct the geological and hydrogeological context. The large amount of groundwater in the basin is linked to a high permeability of the shallow rock mass. The concentration of supplies to the spring is due to morphological reasons and the occurrence of major fractures that carry also a part of the losses of the stream. The purposes of the study are the evaluation of: the losses (l/s) of stream feeding the spring, the percentage of water of the stream that reaches the spring and the percentage of the spring discharge supplied by the stream. The hydrogeological surveys consisted of sodium-chloride tracer tests for the measurement of the stream discharge and of the overflow of the spring, and tracer tests of the stream with fluorescent tracer. The surveys were conducted in three measurement campaigns for different flows of the stream. Findings indicate that, despite the large variation of stream discharge and stream losses, the discharge of spring remains fairly steady and scarcely supplied by the stream. The case study, besides increasing the knowledge about this area, unusual for the hydrogeological features, provides a methodological approach to the evaluation of the relationship between rivers and groundwater.