Comparison of the modeling results of nitrate concentrations in soil water below the root zone in the local and regional scale

The article presents a comparative analysis of the modeling results of nitrate concentrations in water below the root zone of the soil in the local and regional scale. In this research, the fild-scale DNDC (Denitrifiation – Decomposition) and the regional-scale GROWA–DENUZ (ger. Großräumiges wasserhaushalt – Denitrifiation im durchwurzelten Boden) models were applied to the study area of the shallow aluvial aquifer of the Spodnje Savinjska dolina in the central part of Slovenia. Using the concept of Hydrological Response Unit (HRU) and Cohen Kappa statistical analysis of the degree of agreement and assessment of the reliability of the results of spatial modeling of nitrate in soil water below the root zone, we determined and interpreted the areas of maximum agreement and disagreement of model results. A good agreement was found at the highest modeled concentrations of nitrate in soil water, whereas the greatest deviations were detected primarily in the lower part of the range. The main reasons for disagreement were differences in the estimation of the denitrifiation conditions in the anaerobic environments of gley-soils with the shallow groundwater and differences in fertilisation scenarios and agricultural practices

Groundwater recharge in Slovenia - Results of a bilateral German-Slovenian Research project

Groundwater is a resource of utmost strategic importance for Slovenia and Germany providing drinking water of good quality to its population. For decades, management of this key resource has received the highest priority of our national hydrological services. In the framework of the service activities in both countries, groundwater status in terms of quantity and quality has been observed and studied systematically for more than 50 years. In the eighties of the last century the first models forgroundwater recharge assessment at local and regional scale were developed. However, long time assessment of groundwater status and estimation of groundwater recharge for heterogeneous hydrogeology systems of entire countries were not available. In this respect the GROWA model, developed at the Agrosphere Institute of Research Centre Jülich, was one of the first groundwater recharge models that was applicable at the level of river basins and Federal States in Germany. The transfer and application of the GROWA model to groundwater systems of the Republic of Slovenia was a pioneering effort, establishing for the first time a groundwater recharge model covering the whole territory of Slovenia and not focusing on individual aquifers only, being the practice in Slovenia before. [...

Results of radiometric and geochemical measurement for the natural radioactivity map of Slovenia

In 1990, a program was initiated to cover Slovenia with portable gamma-ray spectrometer measurements on a 5 x 5 km grid. The measurements were performed with a four channel Scintrex GAD-6 spectrometer. Five gamma-ray measurements were taken at each of 816 locations. Samples of the upper 10 cm of soil profile were collected for laboratory analysis. Uranium in samples was determinedby delayed neutron method (DNC). Other 35 elements: Ag, Al, As, Au, Ba, Be,Bi, Ca, Co, Cr, Cu, Fe, K, La, Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Sb, Se, Sn, Sr, Th, Ti,U, V, W, Y, Zn and Zr were analyzed by plasma-coupled emission spectrometry (ICP). The field gamma-ray measurements were converted to ground concentrationsof potassium, uranium and thorium. These show good correlation with the laboratory analyses of soil samples. Regardless of the wide spaced sampling, the produced maps show relatively good correlation with main geological units. They demonstrated that the methodology can be successfully implemented for environmental monitoring, geological mapping and mineral exploration. The product ofthis project is the frist natural background radioactivity map of Slovenia covering the entire country

Assessment of groundwater quantitative vulnerability to climate change in Slovenia

Assessment ofthe potential impact of climate change on groundwater recharge and availability of groundwater resources is as essential in Slovenia as it is elsewhere. Adaptive planning is of immense importance when aiming for reduction of negative impacts, even more so in areas with the highest groundwater exploitation levels and the lowest adaptive capacity. We have assessed quantitative groundwater vulnerability to climate change through potential impact and adaptive capacity indicators for all groundwater bodies in Slovenia. High and moderatly high quantitative groundwater vulnerability can be observed in merely 9 % of Slovenian territory. The highest quantitative vulnerability was accounted to shallow alluvial groundwater bodies in the northeastern part of the country, where the annual change in groundwater recharge due to climate change until the middle of this century is expected to represent more than a quarter of the current average annual groundwater extraction

The assessment of the required groundwater quantity for the conservation of ecosystems and the achievement of a good ecological status of surface waters

Assessment of the available quantity of groundwater is of essential importance for its sustainable use. Modern approaches for estimation of groundwater availability take into account all potential impacts of abstractions, including impacts on groundwater dependent ecosystems and impacts on surface waters ecological status. Groundwater body is in good quantitative status if groundwater abstractions do not cause signifiant damages to groundwater dependent ecosystems and signifiant diminution in the ecological status of surface water bodies. The methodology presented in this paper was developed as an integral part of the assessment of the quantitative status of groundwater bodies in Slovenia and is tailored to the characteristics of the groundwater dependent ecosystems as well as hydrological and hydrogeological conditions in the Slovenian territory. Two different approaches were implemented; for forest habitats on alluvial aquifers, and habitats of amphibians and molluscs in karst areas. Estimates of the required quantity of groundwater for groundwater dependent ecosystems conservation were performed at the level of groundwater bodies and annual averages of temporal variables of the water balance, calculated with the regional water balance model GROWA-SI. In the areas of groundwater bodies with groundwater dependent ecosystems estimated quantity present 0.1 % - 12.4 % of the groundwater recharge. The estimated share of annual renewable quantity of groundwater to maintain the ecological status of surface waters for the entire territory of Slovenia is 23.2 %. The largest share, 30 % is in north-eastern Slovenia and the lowest in the north-west part of Slovenia with a 16.6 % average annual renewable quantity

Groundwater quantitative status assessment for River Basin Management Plan 2022–2027 (RBMP III)

Ocena količinskega stanja podzemnih voda je del Načrta upravljanja voda 2022–2027 (NUV III). Z njo po določenih kriterijih ovrednotimo količinsko stanje na 21 vodnih telesih podzemnih voda v Sloveniji kot »dobro« ali »slabo«. Ocena je izvedena s štirimi preizkusi, kjer analiziramo vpliv odvzemov (črpanih količin) podzemne vode na: količine podzemne vode in vodno bilanco, ekološko stanje površinskih vodnih teles, kopenske ekosisteme odvisne od podzemne vode in vdore slane vode ali vode slabše kakovosti v vodonosnik. Končno skupno oceno, na podlagi opravljenih preizkusov, določa kriterij najslabše ocene. Na podlagi rezultatov izvedenih preizkusov imamo 20 vodnih teles ocenjenih s skupno oceno »dobro«. Vodno telo Dravska kotlina pa je ocenjeno kot »slabo«, ker črpanje podzemne vode povzroča vdore vode slabše kakovosti v vodonosnik. Zadnja obdobna ocena količinskega stanja 1991–2020 razkriva, da imamo v plitvih vodonosnikih podzemnih vodnih teles letno na razpolago dobrih 4 milijarde m3 podzemne vode. Odvzemi podzemne vode (črpane količine) so v obdobju 2014–2019 v plitvih vodonosnikih dosegali povprečno 135 milijonov m3/leto. Na območju globokega geotermalnega vodonosnika v Murski kotlini so odvzemi v tem obdobju ocenjeni na 2,5 milijona m3/leto. Numerični modeli simulirajo omejeno napajanje, ki se kaže kot izcejanje iz okoliških kamnin v geotermalni vodonosnik v višini približno 2,3 milijona m3 termalne vode na leto.The Groundwater quantitative status assessment is part of River Basin Management Plan 2022–2027 (RBMP III) and is used to evaluate, according to certain criteria, the 21 groundwater bodies (GWBs) in Slovenia. GWB can achieve good or poor quantitative status. The assessment is carried out with four tests, where the impact of groundwater abstraction (pumped quantities) on: groundwater quantity and water balance, the ecological status of associated surface water bodies, groundwater dependent terrestrial ecosystems and the intrusion of saline or poor water quality into the aquifer is analyzed. The final overall assessment of each groundwater body, based on the completed tests, is determined by the criterion of the worst test assessment. Based on the results of the tests, within the assessment period, 20 GWBs in Slovenia achieved good quantitative status. GWB Dravska kotlina achieved poor quantitative status, because the pumping of groundwater causes poor quality water intrusions into the deeper aquifer of that groundwater body. Within the last assessment period 1991–2020, approx. 4 billion m3 of groundwater was available annually in shallow aquifers within groundwater bodies. Groundwater abstraction (pumper quantities) in the period 2014–2019 reached an average of 135 million m3. In the area of deep geothermal aquifers of the Mura basin, abstractions were estimated to sum up to 2.5 million m3 per year. Latest numerical simulations point out induced aquifer recharge of approx. 2.3 million m3 of thermal water

Groundwater quantitative status assessment in Slovenia

The framework for the integrated water management of the entire EU area has been set, when the European Parliament and Council passed the Directive 2000/60/EC in 2000. According to the directive, the evaluation of meeting the environmental objectives is based also upon the assessment of quantitative and chemical status of individual groundwater body.The assessment of quantitative status of groundwater bodies under the Groundwater Directive of EU is based on the definition of the available groundwater quantity.Thisisalong period mean annual renewable quantity of water in the groundwater body, reduced by the quantity of the long period annual groundwater discharge, which is required for sustaining ecological objectives concerning surface water bodies and preservation of the ecosistems, connected with the groundwater bodies.Methodological approach and the results of the first groundwater quantitive status assessment for 21 groundwater bodies in Slovenia are given in this paper. The assessment of the available groundwater quantity in Slovenian groundwater bodies in the period from 1990 to 2001 are 1,43 ⋅ 109 m3 per year, and 727,4 m3 per capita per year respectively. In the year 2002 abstracted groundwater (0,23 ⋅ 109 m3 per year) represents 15 percent of the available groundwater reserves in Slovenia. For all Slovenian groundwater bodies quantitative status was assessed as good

Model-based assessment of groundwater recharge in Slovenia

The implementation process of the EU water legislation (EU WFD, EU GWD) has put pressure on environmental managers to create, analyse and disseminate hydrological data in recent years. In this context, distributed hydrological model results at the macro scale (>10,000 km2) have gained importance for the Environment Agency of the Republic of Slovenia, too. Within a joint project the distributed water balance model GROWA, developed for Germany, has been adapted to Slovenia by re-calibrating the routine for determining the average annual groundwater recharge rate. This routine consists mainly of a base flow index approach (BFI). This BFI is based on 41 different site conditions in Slovenia, whereas lithology dominates the recharge process. This paper outlines the general GROWA approach, the required input data, and the calibration process. Validated model results for the period 1971–2000, especially total runoff and base flow, are presented and discussed. These results have been used already for practical water management issues in Slovenia on European, national and regional level. It is shown that Slovenian groundwater resources exhibit high regional and seasonal variability. Tendencies of more frequent and more pronounced droughts have been detected. As demonstrated by the results GROWA is a valuable tool for the spatially distributed assessment of groundwater recharge in Slovenia

Groundwater quantitative status assessment for River Basin Management Plan 2015-2021 in Slovenia

The improved methodological approach of the groundwater quantitative status assessment in Slovenia and the results of the assessment period 2010-2013, taking into account the new reference thirty-year period 1981- 2010, are presented. Within the assessment period quantitative status in all shallow alluvial aquifers of 21 groundwater bodies in Slovenia is assessed as good, with a medium to high level of confience. Groundwater quantitative status assessment methodology considers the processes of the whole hydrological cycle and the results of groundwater recharge modelling. The methodology incorporates the concept of sustainable groundwater use to preserve the quantities not causing environmental and other harm (unacceptable environmental and other consequences). Legislative baseline for assessing the impacts of groundwater abstraction on renewable and available quantities of groundwater introduces new methodology by abandoning obsolete mining concept of "calculation of groundwater reserves"

Model-based assessment of groundwater recharge in Slovenia

The implementation process of the EU water legislation (EU WFD, EU GWD) has put pressure on environmental managers to create, analyse and disseminate hydrological data in recent years. In this context, distributed hydrological model results at the macro scale (>10,000 km2) have gained importance for the Environment Agency of the Republic of Slovenia, too. Within a joint project the distributed water balance model GROWA, developed for Germany, has been adapted to Slovenia by re-calibrating the routine for determining the average annual groundwater recharge rate. This routine consists mainly of a base flow index approach (BFI). This BFI is based on 41 different site conditions in Slovenia, whereas lithology dominates the recharge process. This paper outlines the general GROWA approach, the required input data, and the calibration process. Validated model results for the period 1971–2000, especially total runoff and base flow, are presented and discussed. These results have been used already for practical water management issues in Slovenia on European, national and regional level. It is shown that Slovenian groundwater resources exhibit high regional and seasonal variability. Tendencies of more frequent and more pronounced droughts have been detected. As demonstrated by the results GROWA is a valuable tool for the spatially distributed assessment of groundwater recharge in Slovenia