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1 65 56 74 M50 М52 Hidrodinamička analiza, kao metodološki postupak, korišćena je za simulaciju režima i kvantifikaciju bilansa podzemnih voda na širem području Površinskog kopa „Jakovačka Kumša“. Istražni prostor obuhvata i deo beogradskog izvorišta podzemnih voda koje se nalazi u neposrednoj blizini površinskog kopa, u priobalju reke Save. Na površinskom kopu se vrši eksploatacija peska, koji se koristi kao građevinski materijal. Analizom i sintezom podataka koji se odnose na geološke i hidrogeološke ka-rakteristike područja, u radu je prikazan trodimenzionalni hidrogeološki model istražnog područja. Prevođenje hidrogeološkog modela u hidrodinamčki izvršeno je primenom numeričke metode konačnih razlika i softverskog koda Modflow, zatim diskretizacije oblasti obuhvaćene modelom i vremenskog intervala, „uvozom“ hidrogeoloških parametara porozne sredine i postavljanjem graničnih i početnih uslova na modelu. U radu su prikazani rezultati hidrodinamičkog modela režima izdani istražnog područja u vidu karata rasporeda pijezometarskog nivoa, kao i bilansa podzemnih voda. Ovako postavljen trodimenzionalni hidrodinamički model predstavlja bazu za dalje prognozne hidrodinamičke proračune, kao i procenu uticaja eksploatacije peskova na kvalitet podzemnih voda tog dela beogradskog izvorišta.

124463 582 M20 М21а The origin and effect of hydraulic resistances on the rate of ageing of radial collector wells are identified through numerical hydrodynamic analysis. The research includes hydrodynamic modeling of one such well with new laterals at Belgrade well field. The performance of the laterals is aggravated by rapid ageing. The change in the hydraulic parameters of the laterals during the first decade of operation is analyzed through simulations of the groundwater regime with realistically specified geometries and hydraulics of the laterals. Contrary to previous investigations, two genetically different types of clogging were identified. The initial hydraulic resistances are a result of colmation due to the gravel pack grain-sizes and screen slot sizes being mismatched with the sand and gravel sediments of the aquifer deposited at the depth of the laterals. Colmation affects the hydraulic performance of the laterals. Well ageing is aggravated by incrustation, caused by high iron concentrations in the captured groundwater. The research highlights a strong correlation between increasing resistances at the laterals, on account of iron precipitation, and groundwater entrance velocities at the laterals. It is possible to differentiate between colmation and incrustation and accurately define the increase in resistances at the laterals by specifying known thicknesses of the near-lateral screen zones and quantifying hydraulic conductivities of those zones. MODFLOW–USG code and Connected Linear Network Process package are recommended for simulating laterals and defining real rather than hydraulically equivalent characteristics of the laterals, as an approach to hydrodynamic investigations relating to radial collector wells.

The paper examines the possibility of hydraulic characterization of radial well laterals in a manner that does not require prior hydrodynamic analysis by simulating groundwater extraction conditions on a numerical model. The first step of the proposed approach is to assess the groundwater level regime formed in the capture zone when the well is operating, which is indicative of the functional condition of the laterals and the aquifer potential in terms of groundwater availability. Then the efficiency of the laterals is examined through the hydraulic function of the skin zone, depending on its filtration properties. An expression for groundwater flow from the aquifer to the laterals (commonly used to simulate laterals on a hydrodynamic model) is employed to define representative values of the conductance coefficient of the skin zone (as an indicator of colmation), and then applied to several wells at Belgrade Groundwater Source. The present research shows that a conductance coefficient of [Ks/ds]=1.0×10-4 s-1 can be considered as the threshold value in relation to which the effects of colmation of well laterals are exhibited, which is consistent with the results reported by researchers who studied the effect of skin zone conductance on the occurrence and nature of the so-called early drawdown at radial collector wells. In addition to gaining insight into the present condition of the laterals, the proposed approach can be used to study the progress of colmation at different points in time and to quantify the effectiveness of regeneration of laterals. [Projekat Ministarstva nauke Republike Srbije, br. OI176022, br. TR33039 i br. III43004]

A groundwater control system was designed to lower the water table and allow the pumping station “Bezdan 1” to be built. Based on a hydrodynamic analysis that suggested three alternative solutions, multicriteria optimization was applied to select the best alternative. The fuzzy analytic hierarchy process method was used, based on triangular fuzzy numbers. An assessment of the various factors that influenced the selection of the best alternative, as well as fuzzy optimization calculations, yielded the “weights” of the alternatives and the best alternative was selected for groundwater control at the site of the pumping station “Bezdan 1”. [Projekat Ministarstva nauke Republike Srbije, br. OI-176022, TR-33039 i br. III-43004]

42 24 1 M50 M53 The Visočica River rises in Bulgaria, on the Berovo Mountain. Its course in Bulgaria is 16.7 km long. It enters Serbia near the village of Donji Krivodol. Up to the village of Pakleštica, or the beginning of Lake Zavoj, its right-bank tributaries are the Krivodolštica, the Vodenička, the Rosomačka and the Dojkinačka. There are no left-bank tributaries. Among the tributaries, water levels and discharges are gauged only on the Dojkinačka River. The Vodenička had also been gauged but only up to 1978. Originally, there were four river gauging stations on the Visočica. However, three of them have been decommissioned: at Pakleštica, Visočka Ržana and Izatovac. The only remaining station is at Braćevci. For their own needs, Pirot HPP activated the station at Pakleštica in 1990 and at Visočka Ržana in 2011. Based on available data, the paper presents a preliminary assessment of annual and monthly discharges of the Rosomačka and the Vodenička. Topographic water divides were used for the analyses. Река Височица настаје на територији Републике Бугарске у области Беровских планина, где формира ток дужине око 16.7 км. На територију Републике Србије улази код села Доњи Криводол и до Паклештице, односно до почетка формирања Завојског језера, са десне стране прихвата воде Криводолштице, затим Воденичке, Росомачке и Дојкиначке реке, док са леве стране нема притока. Од поменутих притока, осматрања водостаја и мерења протицаја тренутно се врше само на Дојкиначкој реци, а вршила су се и на Воденичкој реци, али су још 1978. прекинута. На реци Височици постојала су укупно 4 водомерна профила од којих су три угашена: в.с. Паклештица, в.с. Височка Ржана и в.с. Изатовац, док вод. ст. Браћевци још увек је у функцији. Од стране ХЕ Пирота, за сопствене потребе су вод. профил Паклештица активирали 1990. а 2011. године и профил Височка Ржана. На основу свих постојећих и доступних података, у раду је дата прелиминарна оцена средње годишњих и месечних протицаја Росомачке и Воденичке реке. За све прорачуне у раду коришћене су топографске вододелнице.

The Kolubara Coal Basin is the largest coal-producing area in Serbia. It is administratively comprised of several open-cast mines: Field A, Field B, Field C, Field D, Field E, Field F, Field G, Veliki Crljeni, Sopic-Lazarevac, Tamnava - West Field, Tamnava - East Field, Radljevo, Zvizdar, Ruklade, and Trlic. The paper focuses on the largest active open-cast mine: Tamnava - West Field. A study and conclusions about the hydrogeologic functions of the lithologic strata, and insight into their spatial interactions, are extremely important for hydrogeologic modeling of a given area. The main purpose of a hydrogeologic model is to derive conclusions about the spread of the aquifers in the study area, their interactions, and groundwater flow conditions. Based on geologic and hydrogeologic exploration, and analysis and synthesis of the collected data, the paper describes hydrogeologic modeling of the open-cast mine Tamnava - West Field. The software used in the research provides a portrayal of the 3D distribution of the aquifers present in the study area. As such, the hydrogeologic model constitutes a basis for developing a hydrodynamic (mathematical) model of the groundwater regime.

This paper presents groundwatermanagement based on the results of groundwater modeling used to simulate theeffects of operation of three dewatering system scenarios of the Buvac open pitmine. Several aquifers exist within the Buvac limonite ore deposit region,which puts ore exploitation at risk. Groundwater modeling, was used tounderstand the groundwater regime within these aquifers. A previous numericalmodel (2007) was completed for the state of the groundwater regime prior to theopening of the open pit mine. During the last five years, the development ofthe open pit mine and associated activities have drastically modified the flowfield. The model was modified for the new conditions on the site, and with thenew data from the groundwater and surface water regime monitoring. The existingsystem of protection of the open pit mine from groundwater encompasses drainageof the alluvial aquifer and the ore body aquifer. This paper analyzes threescenarios of the open pit protection from groundwater for the period from 2013to 2024. The new model was used to simulate the effects of operation of thethree proposed dewatering systems. The differences in the effects of operationof the scenarios were quantified through the conditions of groundwater levelsand water budget. Recommendations have also been given for performingprediction calculations in the case of existence of drainage wells, with themost effective dewatering system determined from a hydrodynamic aspect. Theresults presented in this paper may be used for developing an effectivedewatering program.

A sufficiently long spring discharge regime monitoring data set allows for a large number of analyses, to better understand the process of transformation of precipitation into a discharge hydrograph. It is also possible to determine dynamic groundwater volumes in a karst spring catchment area, the water budget equation parameters and the like. It should be noted that a sufficiently long data set is deemed to be a continuous spring discharge time series of more than 30 years. Such time series are rare in Serbia. They are generally much shorter (less than 15 years), and the respective catchment areas therefore fall into the ?ungauged? category. In order to extend existing karst spring discharge time series, we developed a model whose outputs, apart from mean monthly spring discharges, include daily real evapotranspiration rates, catchment size and dynamic volume variation during the analytical period. So far the model has solely been used to assess the discharge regime and water budget of karst springs. The present paper aims to demonstrate that the model also yields good results in the case of springs that drain aquifers developed in marbles. Belo Vrelo (?White Spring?, source of the Tolisnica River), which drains marbles and marbleized limestones and dolomites of Cemerno Mountain, was selected for the present case study.

Projecting of the dewatering system of the open-pit mine “Buvac” (Republic of Srpska, Bosnia and Herzegovina) is based on the use of hydrodynamic model of groundwater regime. Creating the hydrodynamic model of the open-pit mine “Buvac“ was made in phases, which began by basic interpretation of collected data, along with schematization of the groundwater flow and flow conditions, and finally, forming and calibration of model. Hydrodynamic model was created as multilayer model with eight layers. Calibration of the hydrodynamic model is the starting point for making prognosis calculation in order to create the most optimal system of open-pit mine protection from groundwater. The results of model calibration indicated that the rivers Gomjenica and Bistrica, precipitation and inflow from karstified rocks are the primary sources of recharge of the limonite ore body “Buvac”.