1. UNIVERSITY OF BELGRADE
FACULTY OF MINING AND GEOLOGY
DEPARTMENT OF HYDROGEOLOGY
MASTER'S THESIS
HYDROGEOLOGICAL CHARACTERISTICS AND WATER BUDGET
ASSESSMENT OF LELIC AND JADAR KARST AQUIFERS IN INNER
DINARIDES OF NORTHWESTERN SERBIA
Summary
Mentor:
Dr Zoran Stevanović, professor
Student:
Veljko Marinović, G602/13
Belgrade, 2014

2. INTRODUCTION
Karst areas cover a large part of Earth’s surface and it is estimated that 20-25% of world
population is being supplied by karst groundwater. This number includes also the population in Serbia,
since karst areas cover almost 30% of our country. Dinaric belt and Lelić karst as a part of Inner
Dinarides of western Serbia, stand out among them. Lelić karst represents a huge area of bare karst and
surely one of the most interesting aquifer of karst groundwater. Besides this area, there is also Jadar
karst area in western Serbia, which is remarkable for geological and hydrogeological features as well
as the place of birth and first contact with karst of Jovan Cvijić, the founder of the modern karst science
in Serbia and worldwide.
The very first step applied in this thesis is delineation of groundwater bodies in the north-
western Serbia in accordance to Water Framework Directive (WFD, 2000). After that, the groundwater
budget or the volume that can be exploited has been calculated for each of bodies. Rainfalls and surface
inflow as inputs and spring discharge, surface outflow and water loses as outputs have been taken into
account in this budget assessment. Considering aforementioned parameters, dynamic, static, available
and potentially available reserves have been estimated and compared with given water demands for
2021 (Water Management Plan of Serbia, 2011).
GEOGRAPHICAL POSITION AND MAIN GEOLOGICAL AND HYDROGEOLOGICAL
FEATURES OF THE STUDY AREA
Lelić and Jadar karst areas are located in north-western Serbia (Fig. 1) and this region belongs
to the Dinaric belt, according to the geological zoning. It is estimated that about 380 000 citizens live
in this region, mostly in cities, among which Valjevo and Loznica are the biggest ones.
Fig. 1. Location of Lelić and Jadar karst areas in north-western Serbia
In terms of basic features of the study area, it should be noted that precipitation and air
temperature data taken from the main meteorological stations do not fully reflect the climate regime of
karst terrains, mostly because of non-representative alttitude of the main meteorological station when
it comes to karst areas in this region. Thus, climate data have been approximated on the basis of isohyet

3. and isotherm maps (Ducić & Radovanović, 2005), which show average annual rainfalls between 950
and 1050 mm and average annual air temperature below 10ºС.
According geological and tectonic characteristics, the study area belongs to the Inner Dinarides
of Serbia and it is characterized by the existence of 3 tectonic units, which are distinguished by their
lithological, lithostratigraphic, tectonic and paleogeographic features (Fig. 2). Those are: Drina area in
the south-west part, Jadar area in the north and north-east part and the third zone, located between the
two, composed by ultramafic rocks and diabase-chert formation from Mesosoic era (Mojsilović et al.
1975). The first one (Drina area) is composed by Paleozoic rock complex (sandstones and schists) and
Mesosoic sediments. It should be noted that this area is charaterized by very complex and overthrusting
structures. Jadar area has simple geological features often with superposition of layers. Paleozoic rocks
(Upper-Devon carbonates and Devon-Carbonic sandstone-foliated rocks) and Mesosoic rocks (mostly
presented by carbonates) belong to this area. The third area, located between Jadar and Drina area is the
zone composed by Mesosoic sediments, mafic, ultramafic and sedimentary-volcanogenic formations of
diabase-chert formation (Mojsilović et al. 1975). Also, it can be noticed that this zone extends almost
parallel to the direction of the Podrinjskovaljevske mt.
Fig. 2. Simplified geological map of the study area
When it comes to hydrogeological characteristics, intergranular, fissure and karst aquifers (with
various hydrodynamic characteristics) as well as impermeable rocks are present on the study area (Fig.

4. 3). Intergranular aquifer has the largest distribution in the far northern part of the study area, while its
distribution in southern part is limited. Among them, alluvial deposits of the Drina, Kolubara, Tamnava
and Ub river, composed by sand and gravel sediments with high hydrodynamic characteristic, stand
out. Besides unconfined aquifers, there are also confined aquifers on the study area, particulary in
Mačva and Posavo-Tamnava region. Presence of artesian aquifers, composed by fine-grained sand,
rarely sandy gravel has been determined within Neogen sediments that transgressively lay over
crystalline schists and granite of Cer mt. (Komatina, 1978). Fissure aquifers has a small distribution and
can be found within serpentine – peridotite masif of Povlen ad Maljen mts., Werfenian deposits as well
as magmatites of Cer and Boranja mts. Springs within this aquifer type are not rare, but with very low
discharge, not greater than 1 l/s, usually less than 0,1 l/s (Filipović et al. 2005).
Fig. 3. Simplified hydrogeological map of the study area
Karst aquifers are mostly located within Triassic limestones (Upper and Middle Triassic),
Jurassic (Malm) and Cretaceous limestones. The largest distribution of open karst terrrains are located
in central part of the study area, named as Lelić karst area. This area is composed by Upper Triassic
limestones (Anisian and Ladinian stage), diabase-chert formation, while underlying formation are
Werfenian sediments (schist sandstones). Lelić karst area extends between Poćuta village on west to
Vrujci on east, and between Kozomore on south to Nepričava and Ćelije on north, with total area of
250 km2
(Simić et al. 1999). Region of Lelić karst is mildly dipping to north (where karst springs are

5. located), while the area are bounded by impervious rocks (i.e. hydrogeological barriers). River network
is not well developed due to large distribution of limestones whose dissolution rate prevents large river
flows. There are several large karst springs along the northern edge of Lelić karst, discharging the whole
area. Those springs are Paklje spring (Qsr = 300 l/s), Gradačka vrela spring (Qsr = 1100 l/s) and Petnica
spring (Qsr = 250 l/s). Besides them, there are also several discharge zones of karst groundwater that
drainage this karst aquifer: Ključka vrela spring, Orlovac, Paštrić and Vrujci. Also, it should be
mentioned that there is an assumption of existance of karst below alluvial and Neogene sediments on
the depth of 65 – 150 m, near Lajkovac, Ćelije and Nepričava area.
Besides Lelić karst area, there are also several smaller open karst areas on the study area. Those
are karst areas near Kosjerić where Taorska vrela spring (Qsr = 40 l/s) is located as well as isolated open
karst areas drainaged by Banja Koviljača springs (Qsr = 25 l/s), Tronoša spring (Qsr = 15 l/s) and Gornja
Trešnjica spring (Qsr = 80 l/s) (data are based on personal communication with Z. Stevanović).
Besides aforementioned karst terrains composed mostly by Triassic and Creataceous
limestones, in the northern part of study area there are Neogene limestones in which cold and termal
karst groundwater emerge. Also, presence of confined karst groundwaters as well as complex aquifers
(karst-integranular type) are confirmed in this area.
METHODOLOGY
The very first step is defining geometry of groundwater bodies or aquifers’ dimensions and
character. Such an approach is suggested by Water Framework Directive (WFD), that gives the concept
of delineation of groundwater bodies and its budget assessment, in order to preserve good qualitative
and quantitative status of groundwater. However, WFD does not give methodology of delineation
strictly, because it is not possible to set an uniform concept of delineation to be applicable for all region
in Europe. Thus, WFD defines delineation of groundwater bodies as itterative process of segregation of
groundwater bodies which should be adjusted by specific geological and hydrogeological
characteristics of area.
Many authors have dealt with groundwater budget assessment, so Poehls & Smith (2009) state
that groundwater budget presents the quantification of the recharge - discharge interrelationships within
a watershed basin. On the other hand, Stevanović (1991) states that „groundwater budgeting should be
treated as the entire complex dynamic process of recharge, circulation and discharge of groundwater,
as analysis of input and output elements, and all the factors influencing that process in certain time
cycles.“ Dragišić & Živanović (2014) state the aforementioned definitions of groundwater budget as
following equation (1):
𝑼 − 𝑰 = ± ∆𝑾 (∆𝒕) (1)
where:
U – inputs (as precipitation, surface/underground inflows form other basins and all other aspects of
water entering into watershed, i.e. articifial recharge)
I – outputs (as surface/underground outflows, evapotranspiration, spring discharge, groundwater
exploitation)
W – changes in the volume of water on the study area, during the observation (Δт)
Δт – discretization period of time for which the water balance is calculated
Groundwater budget calculations should be given separately for each aquifer type due to
differences in the importance of input parameters. The budget parameters for karst aquifers have the
following dependence:
P + Is + Ig = Rf + Et + Eg + Qs + Qsb + Qa ± R ± E (2)
where:
I O

6. I – input parameters
P – precipitation
Is – surface inflows
Ig – underground inflows
Rf – surface outflows
Et – evapotranspiration
O – output parameters
Qs –spring discharge
Qsb – underground discharge
Qa – artificial recharge
Eg – evaporation from water table
R – groundwater reserves variation
E – error
If all of the aforementioned parameters were known, the budget equation would be solved very
easily. However, estimation of some parameters are possible only on the basis of the assessment, while
some factors may be ignored. For that reasons as well as for simplification of the karst groundwater
budgeting, the budget equation can be aproximated by the following equation (Stevanović, 1991):
P = Qvr + G (3)
where:
P – effective rainfalls
Qvr – sumarized value of spring discharges
G – sumarized value of all other output factors (evapotranspiration, surface outflows and underground
outflows)
Such a budget equation is suitable for the assessment of, so-called rough budget as well as
determination of possibilites for water absorption of karst terrains.
RESULTS AND DISCUSSION
According to the specific geological and hydrogeological features of the study area, three
groundwater bodies have been delineated: groundwater body „Povlen“, groundwater body „Lelić“ and
group of groundwater body „Gučevo“ (Fig. 4). Besides Lelić karst area, only minor "oasis" of open
karst areas are present on the study area, that definitely indicate the existence of carbonate sediments at
greater depths. For this reason, the boundaries of water bodies have been delineated only generally,
noting that they should be revised and corrected by carrying out subsequent detailed hydrogeological
research.
The „Lelić“ groundwater body is located on south-eastern part of the study area, southern of
Valjevo, covering the entire area of Lelić karst. This groundwater body occupies an area of 282,7 km2
.
GW body „Lelić“ is the only one with majority of bare karst terrains that occupy 245 km2
or 86,6% of
total area. GW body „Povlen“ is located on S-SW of the study area, mostly distinguished by covered
karst terrains. This GW body covers an area of 329 km2
, of which 76,6 km2
(or 23,3% of total area) are
covered by open karst terrains. For this reason, the boundaries of the groundwater body have been
approximately delineated, mostly based on tectonic features, since the distribution of aquifer below the
geologic units on the surface, has not been defined. Group of groundwater bodies „Gučevo“ is located
on western part of the study area, covering 228 km2
. This one has been defined as a group since karst
terrains are physically separated even though they belong to the same karst region. Covered karst
terrains, making semi-closed hydrogeological structures, have the largest distribution in this GW body
as well as in GWB „Povlen“. Open karst terrains in this group covers 97,8 km2
or 43% of total area.
The groundwater budget assessment is based on the abovementioned methodology. The budget
parameters that have been calculated include dynamic reserves (as mean annual spring discharge), static
reserves (as a result of volume of rock mass and coefficient of karstification), 10% of static reserves
exploitable in the period of 20 years, exploitable part of statis reserves in the period of 20 years,
available reserves as difference between dynamic reserves and minimal spring discharge and potential
available reserves as sum of available reserves and 10% of static reserves exploitable in the period of
20 years. The final results of karst groundwater budget are given in Table 1.

7. Fig. 4. Delineated groundwater bodies within Inner Dinarides of north-western Serbia
Table 1. Review of budget assessment for delineated groundwater bodies
GWB Lelić GWB Povlen GWB Gučevo
Parameter 106
m3
/ann m3
/s 106
m3
/ann m3
/s 106
m3
/ann m3
/s
P 225,4 100% 73,3 100% 88,02 100%
Qsi 22,08 6,31 12,61
Qdis 78,84 33% 7,88 13% 15,77 14%
Qso 31,54 10% 6,31 6% 22,08 20%
L 137,1 57% 65,35 81% 62,78 66%
Qdin 78,84 2,50 7,88 2,50 15,77
Qst
B 367,5 m3
76,6 m3
97,8 m3
C 37,7 m3
126,2 m3
130,2 m3
Qst, 10% 20 ann
B 1,84 m3
0,06 0,38 m3
0,01 0,49 m3
0,02
C 0,19 m3
0,006 0,631 m3
0,02 0,65 m3
0,021
Qav 2,29 0,24 0,4
Qpot. av 2,35 0,27 0,44
Water demands for 2021 (after Water Management Plan of Serbia)
Valjevo 25,9 х 106
m3
/ann Loznica 21,7 х 106
m3
/ann
Legend
P – rainfalls Qst – static reserves (Qst = Fb/c x Hsr x )
Qsi – surface inflow B – bare karst

8. Qdis – spring discharge C – covered karst
Qso – surface outflow
Qst, 10% 20 ann – 10% of statical reserves,
usable in period of 20 years
L – loses;
G = E + Qpod = (P + Qsi) – (Qdis + Qso);
Qav – available reserves
∑ 𝑄 𝑎𝑣 = ∑ 𝑄 𝑑𝑦𝑛 − ∑ 𝑄 𝑑𝑖𝑠,𝑚𝑖𝑛
Qdyn – dynamic reserves (Qdis)
Qpot. av – potentially available reserves ∑ 𝑄 𝑝𝑜𝑡,𝑎𝑣 = ∑ 𝑄 𝑎𝑣 + ∑ 𝑄𝑠𝑡,10%/20𝑎𝑛𝑛
CONCLUSION
Question „how to solve the problem with water supply by drinking water of population in
Valjevo region?“ is becoming increasingly topical. That is the case mostly because this problem was
about to be sold by construction of “Stubo-Rovni” reservoir that started in 1980s. Many negative aspects
that accompanies the construction of reservoirs are reflected primarily in the destruction of karst springs
of Lelić karst area, as well as geomorphological and hydrological characteristics of the Gradac and
Sušica rivers (Petrović D. & Petrović V., 2014). Therefore, this thesis tried to estimate the groundwater
budget of Lelić and Jadar karst area toward to possible alternatives for water supply in this part of
Serbia.
The budget estimation of karst groundwater within groundwater bodies delineated in this part
of Serbia, has shown that this resource could cover all water demands of population. Thus, GW body
„Lelić“ has dynamic reserves in amount of 78,8 x 106
m3
/ann, GW body „Povlen“ has 7,88 x 106
m3
/ann,
while GW body „Gučevo“ accumulates 22,08 x 106
m3
/ann of groundwater. If these amounts of
groundwater are compared to the needs in water for 2021 predicted by WMP (given in Table 1 for
Valjevo and Loznica, as the most populous city of the region), it is evident that karst groundwater can
settle even greater necessity of these, seems oversized amounts of water.
However, it is necessary to carry out hydrogeological research in which reserves, regime and
quality of groundwater should be determined if this resource wants to be exploitated. After overall
research, verification of reserve and monitoring should be next steps to collect more reliable data for
the smooth functioning of the potential water system, or a new verification of the reserve after five
years.
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