Preliminary groundwater modelling by considering the interaction with superficial water: Aosta plain case (northern Italy)

The study is developed through scientific cooperation between the University of Milano-Bicocca and the Regional Agency for Environmental Protection (ARPA) of the Valle d'Aosta Region. Its aim is to produce a decision-support tool to help the Public Administration'manage groundwater and public water supply. The study area is the plain of Aosta, between the cities of Aymavilles and Brissogne; in this area groundwater represents the main source of public water supply. The valley is oriented east-west, along the Baltea for a length of 13.1 km and a width of 4.6 km. The textural and hydrogeological properties of the deposits are strictly connected to glacial deposition and to the subsequent sedimentary processes which took place in glacial, lacustrine and fluvial systems. The study is based on available well information in the Aosta plain - including water wells (133) and piezometers (121) - which have been coded and stored in the well database TANGRAM,. The database facilitates interpretation of the well data, and it allows three-dimensional mapping of subsurface hydrogeological characteristics through database codification and ordinary kriging interpolation. The study is designed to achieve two objectives. The first is to provide the Aosta Public Authorities with a well database in order to simplify groundwater management. The second is to provide Public Authorities with a groundwater flow model of the local aquifer. The model integrates surface and subsurface flows in order to fully account for all important stresses, both natural and anthropogenic, on the groundwater system. It provides a tool for testing hypotheses (such as the impact of new wells) and thereby allows science-based management of the aquifer resource

Results of the workshop on strategies and tools for administrators of the territory of the italian alpine space for the shallow geothermal systems - GRETA Project - Near-surface Geothermal Resources in the Territory of the Alpine Space

I sistemi a pompa di calore che utilizzano la geotermia di bassa profondità (altrimenti nota come a "bassa entalpia") per il riscaldamento ed il raffrescamento degli edifici rappresentano una tecnologia efficiente e vantaggiosa che può contribuire significativamente alla riduzione delle emissioni di gas serra. Nonostante le bassissime emissioni e i costi energetici significativamente ridotti rispetto all'impiego di combustibili fossili, la diffusione dei sistemi che sfruttano l'energia geotermica a bassa entalpia (profondità generalmente comprese tra i 30 e i 150 m dal piano campagna), è ancora limitata da molteplici fattori. In questo ambito, gli amministratori del territorio esercitano un ruolo chiave in quanto, attraverso la predisposizione di strumenti di vario tipo (informativi, normativi e tecnici), essi possono imprimere un impulso importante allo sviluppo dei sistemi geotermici di bassa profondità, ampliando così il ventaglio di tecnologie attualmente disponibili per lo sfruttamento delle fonti energetiche rinnovabili [...

The GRETA project: the contribution of near-surface geothermal energy for the energetic self-sufficiency of Alpine regions

The Alpine regions are deeply involved in the challenge set by climate change, which is a threat for their environment and for important economic activities such as tourism. The heating and cooling of buildings account for a major share of the total primary energy consumption in Europe, and hence the energy policies should focus on this sector to achieve the greenhouse gas reduction targets set by international agreements. Geothermal heat pump is one of the least carbon-intensive technologies for the heating and cooling of buildings. It exploits the heat stored within the ground, a local renewable energy source which is widely available across the Alpine territory. Nevertheless, it has been little considered by European policies and cooperation projects. GRETA (near-surface Geothermal REsources in the Territory of the Alpine space) is a cooperation project funded by the EU INTERREG-Alpine Space program, aiming at demonstrating the potential of shallow geothermal energy and to foster its integration into energy planning instruments. It started in December 2015 and will last three years, involving 12 partners from Italy, France, Switzerland, Germany, Austria, and Slovenia. In this paper, the project is presented, along with the results of the first year of work

Hydrogeological characterization throughout deep geophysical investigations in the Verrès plain (Aosta Valley, north-western Italian Alps)

Although fresh water availability in the Aosta Valley (north-western Italian Alps) is generally granted by glaciers and snow seasonal melting at high altitudes, hydrogeological conditions are not favorable everywhere. Most part of the territory is typically mountainous, with prevailing metamorphic rocks and, secondarily, glacial deposits. Relevant ground water bodies can be found only in the main bottom valley, where glacial excavation, fluvio-glacial and lacustrine sedimentation had maximum intensity, allowing the deposition of important thickness of porous materials. Nevertheless, the geological knowledge of the subsurface is here still poor. These groundwater bodies are monitored by the Environmental Protection Agency of the Aosta Valley Region (ARPA Valle d’Aosta), according to the Italian law (D.Lgs.30/09). This study deals with geophysical investigations in the Verrès plain aquifer (southern Aosta Valley). The main goal of the study has been the first evaluation of groundwater research in potential deep aquifers. Different geophysical methodologies were applied (ERT, TDEM, HVSR, and Re.Mi.), in order to identify the deep aquifer geometry and the rock basement depth

Hydrochemical and Isotopic Applications in the Western Aosta Valley (Italy) for Sustainable Groundwater Management

This research gives an overview of the status of water resources in the western Aosta Valley (Italy). Surface water, groundwater and precipitation were sampled during five sampling campaigns, and chemical analyses were performed and interpreted. Stable isotopes (δ18O and δ2H) were evaluated. This study highlights the relationships between water quality and quantity and local conditions (i.e., aquifer lithology, mixing into the aquifer, proximity to towns, contribution of snowmelt and ice melt to groundwater recharge, amount of rain, and season and altitude of the sampling location). A relationship between dust dispersed in the atmosphere as aerosols from the nearby Piedmont Region and the precipitation chemistry was identified, highlighting the presence of interregional conditions. Furthermore, isotopic analyses allowed the identification of aquifer feeding by both rainwater and glacial meltwater. Additionally, two origins for rainfall were identified: the Mediterranean Sea in winter and the Atlantic Ocean in summer. Finally, a local meteoric water line was calibrated for the study area. This research highlights the importance of implementing both traditional and isotopic techniques for water analysis to achieve optimal and sustainable management of water resources

Preliminary groundwater modelling by considering the interaction with superficial water: Aosta plain case (northern Italy)

The study is developed through scientific cooperation between the University of Milano-Bicocca and the Regional Agency for Environmental Protection (ARPA) of the Valle d’Aosta Region. Its aim is to produce a decision-support tool to help the Public Administration’manage groundwater and public water supply. The study area is the plain of Aosta, between the cities of Aymavilles and Brissogne; in this area groundwater represents the main source of public water supply. The valley is oriented east-west, along the Baltea for a length of 13.1 km and a width of 4.6 km. The textural and hydrogeological properties of the deposits are strictly connected to glacial deposition and to the subsequent sedimentary processes which took place in glacial, lacustrine and fluvial systems. The study is based on available well information in the Aosta plain - including water wells (133) and piezometers (121) - which have been coded and stored in the well database TANGRAM,. The database facilitates interpretation of the well data, and it allows three-dimensional mapping of subsurface hydrogeological characteristics through database codification and ordinary kriging interpolation. The study is designed to achieve two objectives. The first is to provide the Aosta Public Authorities with a well database in order to simplify groundwater management. The second is to provide Public Authorities with a groundwater flow model of the local aquifer. The model integrates surface and subsurface flows in order to fully account for all important stresses, both natural and anthropogenic, on the groundwater system. It provides a tool for testing hypotheses (such as the impact of new wells) and thereby allows science-based management of the aquifer resource

Assessment and mapping of shallow geothermal potential of open and closed loop systems in Aosta Valley (NW Italy)

Ground Source Heat Pumps (GSHPs) are very low carbon-intensive systems [1] and they can strongly contribute to the reduction of CO2 emissions since, heating and domestic hot water account for 40% of the total final energy use in Europe. Furthermore, they do not produce any in situ pollutant emission and they have low operational costs. Nevertheless, the number of installed shallow geothermal plants is still very limited. The GRETA project, funded by the EU program INTERREG Alpine Space, aims at boosting the exploitation of shallow geothermal energy through a number of actions, among which tools to integrate shallow geothermal energy in the renewable energy planning of three pilot areas in Italy, Germany, and Slovenia. The Italian one is Aosta Valley, a small mountainous region of 3,000 km2 and 130,000 inhabitants in NW Italian Alps where GSHPs have gained an increasing popularity in recent years. We hereby present a work divided into two sections. The first one deals with the modeling of closed-loop geothermal potential in order to estimate the thermal power which can be exchanged with the ground with a typical 100m-deep BHE. Four estimation methods are compared, i.e. the German standard VDI 4640(2000) [2] and its update of 2015 [3], the English norm MIS 3005 [4] and the recently developed G. POT [5]. In the second part, we address the open-loop geothermal potential of the Aosta plain. We present a simplified analytical model to estimate the thermal plume size, calibrated with numerical simulations on FEFLOW. This model allowed to estimate and map the maximum sustainable density of GWHPs, expressed as thermal power per unit area (W/m2), depending on the groundwater Darcy velocity and on the aquifer saturated thickness. A demonstration is finally shown for a block in flats of Aosta, proving that the open-loop potential provides a conservative estimation of the thermal power which can sustainably be installed in a urban area. Together, the delivered tools will help public authorities in managing the future development of shallow geothermal technology through energy and land planning