The Ljubljansko polje aquifer, which is the main supply of drinking water for the local population in Ljubljana, Slovenia is highly vulnerable to anthropogenic pollution. In this study, the ...geochemistry of major constituents including nitrate concentrations and the dual isotopes of nitrate were used to ascertain the spatial distribution of processes and nitrate sources in the groundwater from seven wells at three different water supplies: Kleče, Hrastje and Jarški prod. The groundwater is of the Ca2+-Mg2+-HCO3− type approaching equilibrium with respect to dolomite and are moderately supersaturated with calcite. The groundwater nitrate concentrations ranged from 5.32 to 50.1 mg L−1 and are well above the threshold value for anthropogenic activity (3 mg L−1). The δ15NNO3 values ranged from 1.4 to 9.7‰, while δ18ONO3 values were from 6.3 to 34.6‰. Based on isotope mixing model three sources of nitrate were identified: atmospheric deposition, fertilizers and soil nitrogen. At Kleče 8, Kleče 12 and Jarški prod 3 the low δ15NNO3 and high δ18ONO3 values result from pristine nitrate sources, while in Hrastje 3 and Kleče 11 equal amounts of nitrate derived from soils with mixed fertilization and sewage. The data also indicate that the main sources of high nitrate concentrations in groundwater are from fertilizers and sewage-manure (comprising up to 64%). Such levels occurred in the Hrastje and Kleče 11 wells where precipitation is the main source of groundwater. Nitrate derived from atmospheric deposition accounted for approximately 10% of the nitrate in the groundwater. The message from this study is that to reduce the nitrogen load and improve water quality will involve containment and the careful management of sources from urban and agriculture inputs such as sewage-manure and fertilizers.
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•Groundwaters in Ljubljansko polje aquifer are Ca2+-Mg2+-HCO3− waters.•The main sources of nitrate are atmospheric deposition, fertilizers and soil nitrogen.•Sewage-manure nitrate is important at locations where precipitation is the main source of groundwater.
In this paper, we present an assessment of the sensitivity of groundwater-surface water interactions to climate change in an alluvial aquifer, located in the Ljubljansko polje, Slovenia. The ...investigation is motivated by a recent assessment of climate change pressures on the water balance in the Sava River Basin (Gampe et al., 2016). The assessment was performed using a comprehensive hydrological modelling approach, which is based on the direct/indirect communication between FEFLOW and WaSiM/MIKE 11. This modelling framework provides a precise simulation of the critical processes in the study domain, which are the main drivers influencing the interactions between precipitation, river water and groundwater under different future climate scenarios. Climate projections were based on the results of the three regional climate models SMHI-RCA4, KNMI-RACMO22E and CLMcom-CCLM4. The results show that there will be higher levels of local precipitation during 2036–2065, the projected river discharge will be larger in the future compared to 2000–2014, and it is unlikely that the Ljubljansko polje will suffer from water scarcity. In addition, amongst the various sections of the Sava River the section between Črnuče and Šentjakob is the one most sensitive to climate change. By running the models under different climate scenarios a deeper insight into aquifer system functioning was obtained. Investigating impacts of climate change on groundwater and interactions between surface water and groundwater on the local scale is a basis for applying such a study on the global scale, which was still not very well investigated.
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•Impacts of projected climate on surface-groundwater interactions are presented.•The aquifer's sensitivity to the climate is higher if one water source dominates.•The Ljubljansko polje is not going to suffer due to water scarcity (2036–2065).•A comprehensive modelling tool approach was applied.
Water isotope investigations are a powerful tool in water resources research as well as in understanding the impact that humans have on the water cycle. This paper reviews past hydrological ...investigations of the Ljubljansko polje and Ljubljansko barje aquifers that supply drinking water to the City of Ljubljana, with an emphasis on hydrogen, oxygen and carbon stable isotope ratios. Information about the methods used and results obtained are summarised, and the knowledge gaps identified. Overall, we identified 102 records published between 1976 and 2019. Among them, 41 reported stable isotope data of groundwater, surface water and precipitation and were further analysed. Isotope investigations of the Ljubljansko barje began in 1976, while groundwater and surface water investigations of the Ljubljansko polje and along the Sava River began as late as 1997. Isotope investigations of carbon started even later in 2003 in the Ljubljansko polje and in 2010 in the Ljubljansko barje. These investigations were performed predominantly in the frame of short-term groundwater research projects at five main wellfields and sites along the Sava River. Almost no large-scale, long-term stable isotope studies have been conducted. The exceptions include groundwater monitoring by the Union Brewery in Ljubljana (2003- 2014) and precipitation in Ljubljana since 1981. Since 2011, more detailed surveys of the Ljubljansko barje were performed, and in 2018, the first extensive investigation started at wellfields and objects that form part of the domestic water supply system. Given the number of available studies, we felt that publishing all the numerical data and appropriate metadata would allow for a better understanding of the short and long-term dynamics of water circulation in the urban environment. In the future, systematic long-term approaches, including the appropriate use of isotopic techniques, are needed.
Ljubljana field aquifer is an important source of drinking water for the Ljubljana city and surrounding areas. Knowledge of the water balance and of the water flow dynamics through the unsaturated ...zone and recharge of Ljubljana field aquifer is crucial. The water balance assessment of the upper unsaturated zone provides an insight into groundwater recharge and renewal. With the help of build-in monolith weighing lysimeter in Kleče in Ljubljana we have assessed the water balance for hydrological year from March 2014 to February 2015. Water balance parameters, precipitation and evapotranspiration were determined from the changes in the mass of lysimeter and outflow tank. Precipitation events were evaluated based on their duration, intensity and the amount of precipitation. Evapotranspiration and the duration of precipitation were estimated based on the changes of the lysimeter mass. Results show that the chosen period was extremely wet. In the selected hydrological year, precipitation contributed to positive water balance of the upper unsaturated zone, as well as to the recharge of the aquifer.
Groundwater is an important resource for drinking water. Although it is a relatively stable and protected water resource, its quality, especially in highly urbanized catchments, is vulnerable to ...pollution related to unusual events or accidents causing releases of hazardous substances. To ensure the safe supply of drinking water in these cases, prompt actions must be taken and solutions must be delivered under time constraints. This paper describes a decision support system for emergency groundwater management that was developed to improve activities after the discovery of pollution in the catchments of drinking water abstraction wells in the Ljubljansko polje aquifer. It is a system based on a monitoring network and the integration of numerical modeling techniques with expert knowledge. The integration of logically interlinked activities, including the detection of pollution in the groundwater, the simulation of pollution propagation and decision making, into a common system provides a basis for proactive water resource management. The user-friendly interface enables water managers to utilize modeling tools and rapidly access information for mitigating pollution of groundwater resource, which in the presented case significantly contributes to a safer drinking water supply.
Ljubljansko polje aquifer is one of the biggest and most important aquifers in Slovenia. In general it is an unconfinedaquifer, but locally, on the SW part, layers with low hydraulic conductivity ...appear and on those areas perchedaquifers are formed. Based on lithological data from boreholes (emphasizing hydraulic conductivity of lithologicalunits) and use of geostatistical method Sequential Indicator Simulation (SIS) hydrogeological model of westernpart of Ljubljansko polje was made. In the model layers with hydraulic conductivity K < 10-6 m/s and area largerthan 0.07 km2 were defined as potential areas of perched aquifers. The majority of them are located on the foothillsof Šišenski and Grajski hrib.
The presence of nitrates, an important pollutant of drinking water sources, at present doesn’t represent an environmental burden that would demand immediate remedial measures in the aquifer of ...Ljubljansko polje. Nevertheless their presence indicates an anthropogenic influence that can not be neglected.The article discusses the spread of nitrates in the aquifer of Ljubljansko polje and gives an estimation of the influenceoftwoimportantnitrate sources, the agricultural and urban land use. The distribution of nitrates in the area is also discussed and the concentration changes with time are examined closely. The most important nitrate source in the groundwater is determined on the basis of nitrate-nitrogen isotope study. The results are correlated to the known land use of the urban area.Sampling for the present study was performed from the autumn 2002 to the summer 2004. The sampling locations were active wells of the public water supply, industrial wells, sampling wells of the existing monitoring network and the Sava river. The results show an uneven distribution of nitrates in the Ljubljansko polje aquifer. Areas with a concentration of up to 40 mg/l can be found, whereas the values in the river bank are low and comparable to those in the river water. On the average the concentration ranges from 20 to 25 mg/l. The nitrate concentration depends largely on the location in the aquifer and does not show significant changes during the time of the research projects,with some exceptions which confirmalocal input of nitrates from the surface in the vicinityofthesamplingsite.The most positive groundwater nitrate δ15N values were found in the area where the groundwater flows from the densely populated area.The least positive values are foundin the groundwater, where the sampling site is surrounded by entirely agricultural land. The spatial variation of the nitrogen source is important. The δ15N values seem to be more sensitive to nitrate input than the nitrate concentration itself and show changes with time. When the sampling site is far away from the source of contamination the amplitudes of NO3 concentration and δ15N are lower. The reason can be found in the homogenization of the groundwater flow.
Skrb za pitno vodo Cerar, Sonja; Cosma, Claudia; Polajnar Horvat, Katarina ...
2014
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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 to
This volume (‘Former waste disposal sites in dolines and gravel pits’) presents former waste disposal sites in depressions (dolines and gravel pits) using relief analysis of the former and current ...landscape and based on comparing them with one another. A comprehensive methodological approach has been created called the three-dimensional (3D) model, which is used to detect and record unknown, hidden former waste disposal sites in depressions above sensitive aquifers. The research deals with the problem of former waste disposal sites from the viewpoint of discovering them, creating a registry, and studying noticeable surface effects on the landscape (relief, soil, and vegetation).
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