Analysis of the possibility of\ud using the distributed two-dimensional model Flo-2D for hydrological modelling

The paper presents a hydrological model of the Glinščica watershed with the program \ud Flo-2D. The aim of \ud the research was to analyze the applicability of the two-dimensional mathematical model Flo-2D for \ud hydrological modeling and to compare the results with the one-dimensional HEC-HMS model. Flo-2D is \ud a commercial, physically based model with distributed parameters. lts main purpose is \ud modeling river hydraulics. lt continuously computes the rainfall runoff from the watershed according to the \ud topography or a\ud digital elevation model (DEM), the quantity and intensity of precipitation, the land use and soil \ud type. On the other hand, HEC-HMS is freely available software that enables to create a simple and \ud sufficiently detailed hydrologic model on the basis of precipitation, discharge and some watershed \ud characteristics. ln both cases precipitation losses were computed with SCS (Soil Conservation \ud Service) Curve Number loss method. Flo-\ud 2D model was calibrated by varying input and modeling parameters including grid size, roughness \ud coefficients and SCS Curve Numbers. The results of 10-year and 100-year events and 2, 12 and \ud 24-hour storms are also compared. The results of runoff volumes are comparable, but the shape of \ud runoff hydrograph computed with HEC-HMS model is much better. ln the Flo-2D model assessing the \ud Manning roughness coefficient and selecting the size of the grid cells are the most problematic, \ud whereas in the HEC-HMS model it is the assessment of the time of concentration. Calibration of the \ud model with distributed parameters is difficult and time-consuming. The results have shown that the \ud Flo-2D model can be used in hydrological\ud practice only in cases where good input data are available for the model and its calibration.\u

Hydrologic model of Glinščica watershed with program Flo - 2D

The present work begins with description of two-dimensional mathematical model Flo-2D. Its use, functioning and procedure of modeling rainfall - runoff for watershed of river Glinscica is represented. In addition analysis and comparison of the final results with results of one-dimensional model HEC-HMS is described. In the sensitivity analysis of the Flo-2D model, the influences of different parameters were tested - the loss settings, the Manning roughness coefficient, the Froude number, the control parameter TOL and the computational grid size. \ud \ud Direct runoff was computed with the Flo-2D program via the SCS Curve Number loss method procedure. Flo-2D model was calibrated and validated on measured hydrographs and runoff volume of Glinscica watershed for specific rainfall event by varying input and modeling parameters including the control parameters, the Manning roughness coefficients and the SCS curve numbers. The main part of the work contains a comparison of a two-dimensional rainfall runoff model conducted using Flo-2D model with a one-dimensional model HEC-HMS. Statistical analyses were made with the Root mean square error method - RMSE. The 10-year and 100-year storms were also modeled.\ud \ud The results have shown that differences in calibrated parameters SCS CN between 1D and 2D model is due to different mathematical algorithms and numerical model. The topographic data turned out to be the main deficiency.\u

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

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

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

Examples of the assessment of temperatures on the surface of solid ground in design of the shallow geothermal energy extractions

The thermal conductivity of rocks and soils and the mean annual temperature of the ground have the biggest impact on the dimensioning of the extraction of geothermal energy with closed ground-water systems. The method of determining the ground temperature is presented in four ways according to the available data at a given location: 1) we have data on the mean annual air temperature, 2) we only have information about the altitude of the place, 3) nearby is a meteorological station with soil (ground) temperature measurements, and 4) a borehole with a thermogram is in the vicinity. The use of these four methods and the differences between them are illustrated by five examples in different parts of Slovenia (Cerkno, Lucija, Brnik, Babno Polje and Maribor). It has been shown that the ground temperature measured at meteorological stations is on average higher than the temperature calculated from the borehole thermograms. The ground temperature can be well estimated with a regression line between the altitude and the measured ground temperatures at meteorological stations only for the continental part. In the coastal part of Slovenia, such an assessment was not feasible, as only two stations with ground temperature measurements are available. There are significantly more boreholes with thermograms (as much as 458) than meteorological stations with measurements of ground temperature (only 9). For this reason, the use of borehole thermograms makes sense. In addition, the borehole thermograms allow us to calculate the heat-flow density, which is also needed in the dimensioning of geothermal energy extractions. For more comparable assessment of the ground temperature from the thermograms, several thermograms from the recent period 1981-2010 should be available, because this period already contains the effect of global warming of the atmosphere. Since this was not the case, we obtained at all locations according to the method of calculation the lowest value from the thermograms. On the other hand, in most boreholes, the temperature record in the upper 20 m is missing, so in the correct extrapolation of the T-z profile from the deeper section of the profile, we mainly covered sections between 20 and 100 m depth. With this we captured such a course of the T-z profile, which still contains in itself a memory of usually slightly lower temperatures on the surface in the past

Nitrogen Mass Balance and Pressure Impact Model Applied to an Urban Aquifer

The assurance of drinking water supply is one of the biggest emerging global challenges, especially in urban areas. In this respect, groundwater and its management in the urban environment are gaining importance. This paper presents the modeling of nitrogen load from the leaky sewer system and from agriculture and the impact of this pressure on the groundwater quality (nitrate concentration) in the urban aquifer located beneath the City of Ljubljana. The estimated total nitrogen load in the model area of 58 km2 is 334 ton/year, 38% arising from the leaky sewer system and 62% from agriculture. This load was used as input into the groundwater solute transport model to simulate the distribution of nitrate concentration in the aquifer. The modeled nitrate concentrations at the observation locations were found to be on average slightly lower (2.7 mg/L) than observed, and in general reflected the observed contamination pattern. The ability of the presented model to relate and quantify the impact of pressures from different contamination sources on groundwater quality can be beneficially used for the planning and optimization of groundwater management measures for the improvement of groundwater quality