Assessment and mapping of the closed-loop shallow geothermal potential in Cerkno (Slovenia)

The economic viability of Borehole Heat Exchangers (BHEs) depends on the ability of the ground to exchange heat, and maps of the shallow geothermal potential are therefore useful planning tools for future installations. In this work, we present the assessment of shallow geothermal potential in Cerkno, a mountain town of 5,000 inhabitants in western Slovenia. The recently developed G.POT method was applied, taking into account site-specific ground thermal parameters and usage profiles depending on climate conditions. This work is part of the EU-funded project GRETA, aiming at supporting the diffusion of GSHPs in the Alpine territory

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

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 [...

Skrb za pitno vodo

Safeguarding Drinking WaterLjubljana's water resources lie in the immediate vicinity of built-up urban areas or even below them. For decades, they have been safeguarded as water-protection areas, which are specified by implementing regulations. However, formal protection through regulations is insufficient if the goal is to manage these sources in a sustainable manner. One of the most important goals of sustainable management is maintaining suitable provision of fresh drinking water without using any technological procedures toVodni viri mesta Ljubljane so v neposredni bližini pozidanih mestnih zemljišč ali celo pod njimi. Že desetletja jih varujejo vodovarstvena območja. Eden od najpomembnejših ciljev trajnostnega upravljanja je ohranjanje ustrezne oskrbe z naravno pitno vodo brez tehnoloških postopkov njene priprave, kar Ljubljančani uvrščajo visoko na lestvici vrednot življenja v glavnem mestu Slovenije. Upravljanje ogroženih vodnih virov v urbanih okoljih zahteva celosten pristop in stalne aktivnosti. S pomočjo računalniških orodij znamo sisteme simulirati in tako pridobiti dodatna védenja o njihovem delovanju. Ta so v pomoč pri dolgoročnih odločitvah ali na primer ob okoljskih nesrečah. Za ustrezno načrtovanje so potrebna strokovna orodja, ki omogočajo zanesljive, pregledne in kvantitativne ocene učinkov ukrepov. Razpolaganje z zanesljivimi ocenami stanja in napovedmi olajšuje delo odločevalcem in tudi komunikacijo med deležniki. Povezava v monografiji predstavljenih postopkov in rezultatov v sistem izvedljivega upravljanja z vodnimi viri v Ljubljani je dosežek, ki je lahko zgled številnim podobnim okoljem, ne le v Sloveniji, ampak tudi širše

The Impact of Ljubljana’s Waste Deposit »Barje« on Groundwater

Ljubljana’s waste deposit is situated on rather thick formation of quaternary sediments on the northern margin of Ljubljansko Barje (Ljubljana Moor). The upper part of quaternary sediments consists of high compressive silty and clayey layers till the depth of aprox. 33 m. These layers are very heterogeneous and one can only find one continuous clayey gravel layer among them at the depth of 8 m and 4 m thick. Below these layers there is the Upper gravel aquifer and from the depth of 72 m there is the Lower gravel aquifer. The bottom of quaternary sediments is aprox. at 140 m depth. The consolidationof highly compressive upper layers and organic compounds from landfill leachate produce the evident impact by reducing conditions in the geological layers below the waste deposit.Though we can detect the reducing conditions also from natural environment in confined layers and rich organic matter content and also from other sources of contamination in the highly urbanized environment. The geometry of the contamination plume was notinvestigated in detail and also not the redox process dynamics. The advection velocities and actual contamination of groundwater are rather low. Further protection measurements will be designed by the aid of the established monitoring results

Attributive datamodel of national hydrogeolocical database to define groundwater bodies of Slovenia

Hydrogeological investigations of groundwater are based on large amount of qualitative and quantitative data (hydrological, hydrogelological, geological, pedological, geomorfological, meteorological…), information about topography, land use, antropogenic elements and ecosystems, which demands a complex approach to modeling and organizing information into some logical structure of all purpose data model, useful on local, regional and national level. For that purpose at Geological survey of Slovenia we established a Database of hydrogeolocial data to define groundwater bodies of Slovenia in which all significant data of groundwater bodies, aquifers and hydrogeological objects are available. Digital storage of attributive data enables uniformity of standards for collecting, analyzing and management of data, their spatial presentation and distribution, connection with other information systems and important decision – making future analysis

The possibility of drinking water capture for the city of Ljubljana by means of a water tunnel in the area of Krim mountain

The article deals with the possibility of groundwater capture by means of a groundwater drainage tunnel in the area of Krim mountain range for a supplementary water supply of the city of Ljubljana. Within the scope of the investigation, a detailed geological mapping of the area was carried out, and hydrogeological, geophysical andengineering-geological research was performed. A water balance of the recharge area was calculated, indicating considerable quantities of groundwater which could be captured with an underground drainage tunnel. A course of the tunnel was suggested, with its entrance part located on the southern fringes of Ljubljansko barje south ofthe village Strahomer. The tunnel would run in the south-west direction in the Upper Triassic dolomite. Because of low environmental burden in the recharge area of the tunnel and due to good cleaning properties of dolomite it is expected that drinking water of very good quality could be captured by means of the drainage tunnel

Springs on Ljubljana polje and Barje area, significant for quantity and quality condition of the groundwater body (Slovenia)

The intergranular aquifer of Ljubljana Field and the aquifer system of Ljubljana Moor are the most important sources of drinking water for Ljubljana.The springs that appear on the area of both groundwater bodies reflect the groundwater status, quantity and quality. The spring water in the Ljubljana Field appears on vowel change of the gravel terrace. We follow them in the lower part of Ljubljana Field aquiferfrom Fu‘ine to confluence of rivers Sava and Ljubljanica. The spring water directly indicates the condition of groundwater level and the quality.On the Ljubljana Barje there are important springs on the southern edge. These springs are crucial observation point for the quality and quantity status monitoring of the inflow fro main recharge area of Ljubljana Moor aquifers that are exploited for the water supplysystem. By the detailed analysis of older sporadic measurements of springs in Ljubljana Polje and Ljubljansko barje we were able to assess the changes in theirs trends of quantity and to design the monitoring network of springs that would acquire adequate data for the actual and future assessment of quantity an quality of these groundwater bodies in the frame of all other available and representative observation points

Infiltration measurements during dry conditions in an urban park in Ljubljana, Slovenia

A thorough understanding of the hydrologic mechanisms that control the movement of water through the soil is essential for developing effective stormwater management strategies. Infiltration is critical for determining the amount of water entering the soil and controlling surface runoff. Spatial and temporal variations in soil properties strongly affect infiltration rates, which underscores the importance of evaluating field-specific values for hydraulic conductivity, which are also highly dependent on the chosen measurement and evaluation methods. The objective of this study is to determine and compare soil hydraulic conductivity under dry conditions using two field measurement techniques, namely the double-ring infiltrometer (DRI) and the mini-disk infiltrometer (MDI). The results demonstrate the importance of performing multiple replicates of infiltration tests, especially during the dry season, as the initial dry surface caused deviations in hydraulic conductivity estimates for both methods used (DRI and MDI). Significant spatial variability was observed within the radius of the test replicates over short distances (<1 m). In addition, experimental infiltration curves for a selected site were used to evaluate and compare soil hydraulic parameters through infiltration modeling. In general, the Philip, Green-Ampt, and Smith-Parlange theoretical models showed a better fit to the experimental DRI data than the semi-empirical Horton model

Synoptic risk assessment of groundwater contamination from landfills

Waste management in Europe has improved in recent years, reducing the amount of waste disposed at landfills. However, there are still many landfills in the countries. It is well known that landfills that do not have measures in place to control leachate entering groundwater can contaminate groundwater long after the landfill is closed. Collecting monitoring results from all landfills allows permitting and management agencies to improve action plans. This relies on a synoptic risk assessment that allows prioritization and milestones to be set for required actions. The developed method of synoptic risk assessment is based on a conceptual model of the landfill and the results of chemical groundwater monitoring tested at 69 landfills in Slovenia. The study confirms that most landfills have a direct or indirect impact on groundwater quality. All landfills were classified into three priority classes on the basis of the synoptic risk assessment. The results show that a total of 24 landfills have a clearly pronounced impact on groundwater. A total of 31 landfills have a less pronounced impact due to the favorable natural attenuation capacity of the soil or the technically appropriate design of the landfill itself. A total of 14 landfills have a less pronounced or negligible impact on groundwater