HYDROGEOLOGICAL PROPERTIES OF THE PODHALE FLYSCH 77
GEOLOGICA CARPATHICA, 55, 1, BRATISLAVA, FEBRUARY 2004
HYDROGEOLOGICAL PROPERTIES OF THE PODHALE FLYSCH
(CENTRAL WESTERN CARPATHIANS, POLAND)
IN THE LIGHT OF STUDIES ON WATER STORAGE CAPACITY
Polish Geological Institute, Carpathian Branch, ul. Skrzatów 1, 31-560 Kraków, Poland; email@example.com
(Manuscript received April 23, 2003; accepted in revised form October 2, 2003)
Abstract: The paper presents an analysis of the variability in fissuring with depth in the flysch deposits of the Podhale
Basin (Central Western Carpathians). Within the stratigraphic sequence of the Podhale Flysch of nearly 3000 m, a
fractured and permeable 80100 m thick, near-surface zone is very important for the water flow. The thickness of this
zone varies and depends mainly on the lithologic development of the flysch deposits and on their morphological posi-
tion. In the shaly Szaflary and Zakopane Beds (and also in the beds from Brzegi) its thickness reaches only 50 m, while
in the Chocho³ów Beds, where sandstone predominates, it reaches 100 m. The obtained results are comparable to the
regional statistical evaluation of data from the Outer Western Carpathians.
Key words: Central Western Carpathians, Poland, Podhale Flysch, water active exchange zone, hydrogeological
parameters, water storage capacity, flysch.
Examination of water storage capacity, which allows us to ob-
serve changes in permeability with depth, is an important task
in hydrogeological investigations. The purpose of such studies
is to evaluate the permeability of fractured rock masses around
the sites of planned water dams. Studies on the water storage
capacity in the flysch deposits of a near-surface zone were per-
formed in Slovakia and the Czech Republic (e.g. Jetel 1985).
Jetel (1985) found that in the majority of flysch regions the
subsurface zone of fractured and decompressed rocks func-
tions as the main aquifer. In the zone in question, on the re-
gional scale, the mean permeability decreases regularly with
depth, and the lower interface of the subsurface zone of frac-
turing is at the depth interval of 3040 m on average. On the
other hand, the lower interface of the continual system of open
fractures facilitating circulation of ground water in the massifs
built of flysch rocks usually does not exceed 100 m.
The purpose of this paper is to show the differentiation of
permeability with depth in the subsurface zone of the Podhale
Flysch deposits based on the examination of the water storage
The Podhale Flysch, Late EoceneOligocene in age, is the
rock series lying above the Carbonate Eocene. Its largest
thickness, 2996 m, has been recorded in borehole Chocho³ów
PIG-1. The Podhale Flysch was subject to thorough studies
initiated after 1945 (Go³¹b 1959; Watycha 1959; Mastella
1975; Ma³ecka 1981; Kêpiñska 1997). The profile of flysch
deposits comprises, from bottom to top: the Szaflary, Zako-
pane, Chocho³ów and Ostrysz Beds (Figs. 1, 2).
The oldest Szaflary Beds are exposed on the surface in a
narrow belt in the northern wing of the Podhale Basin along a
contact with the Pieniny Klippen Belt. Based on the data from
Fig. 1. General section of the Podhale Flysch.
boreholes, it can be concluded that the Szaflary Beds extend
relatively far southward into the flysch basin, but they do not
reach the southern border of the Podhale Basin. The Szaflary
Beds can be subdivided into lower, middle and upper parts. In
the lower and upper beds, sandstones predominate, while
shales and mudstones prevail in the middle part.
The Zakopane Beds form the thickest formation in the
Podhale Flysch. They rest directly upon the Carbonate
Eocene in the southern wing of the Podhale Basin, while in
the northern wing they occur above the Szaflary Beds. Clay-
shales and mudstones (lower Zakopane Beds), predominate in
the lower part, while in the upper part sandstones (upper Za-
kopane Beds) are abundant.
The Chocho³ów Beds, which mainly form morphological
elevations in the Podhale Basin, rest directly on the Zakopane
Beds. Generally, in the Chocho³ów Beds, two members, upper
and lower ones, are distinguished. Sandstones predominate in
both the members of the Chocho³ów Beds. In the eastern part
of the Podhale Basin, the beds of Brzegi are equivalents of the
upper Chocho³ów Beds, and then its characteristic feature is
predominance of clay-shales (Watycha 1959).
In the western part of the Podhale Basin, above the
Chocho³ów Beds, the Ostrysz Beds (series of thick massive
sandstones), the youngest flysch deposits, are distinguished in
a relatively small area.
Water flow in the Podhale Flysch deposits
The water flow in the flysch aquifer runs in a system of con-
nected fissures. It can be assumed (e.g. Ma³ecka 1981) that the
flysch permeability is controlled by fissuring while inter-gran-
ular porosity of rock masses is less important. Laboratory tests
of the Podhale Flysch sandstones and conglomerates showed
that their inter-granular porosity is low (Table 1).
For quantitative evaluation of the size and percent of fis-
sures in the studied rocks the coefficient of fracturing is used
(Liszkowski & Stochlak 1976). The measurements of the fis-
sures, carried out by the author, allowed the conclusion that in
the area formed by the Zakopane Beds (Nêdzówka region) the
mean fissuring is 0.8 % (inter-bed fissility has not been con-
sidered), while in the Chocho³ów Beds (Kocielisko) it is
2.4 % and locally above 4.0 % (Chowaniec 1978).
Fig. 2. Geological map of the Podhale region (without Quaternary deposits, after Chowaniec 1989 simplified) and location of the study area.
Table 1: Porosity of sandstones of the Podhale Flysch.
Porosity in %
Inter-basin area of
Bia³y Dunajec and
Bromowicz & Rowiñski
HYDROGEOLOGICAL PROPERTIES OF THE PODHALE FLYSCH 79
The thickness of sandstone layers of the Zakopane Beds is
1530 cm and in the Chocho³ów Beds 0.51.5 m. The co-
efficient of fracturing, 2.4 %, is twice as big as the value of the
Magura sandstones of nie¿nica region (Bober & Oszczypko
1964). Results of the studies by Ma³ecka & Murzynowski (1978),
performed in the area of the Podhale Flysch show that the values
of this coefficient differ in a very wide range (Table 2).
In the studies that have been performed until now, due to the
lack of hydrogeological drillings (Pokorski 1965; Boretti-Onysz-
kiewicz 1968; Mastella 1975), the permeability of the flysch
deposits used to be determined at the surface, based on fissur-
ing measurements. The boreholes in the region of Kojsówka,
Szaflary and Jurgów in the 1960s allowed the determination of
the permeability of a certain section of the profile based on ex-
amination of water storage capacity.
Examination of water storage capacity
Water storage capacity obtained at the pressure of 0.2 MPa
is used as a standard according to the BN-75/8950-07 Polish
Branch Standard chart. Specific water storage capacity, of the
value of 0.01 dm
/min/m/0.01 MPa is accepted as the thresh-
old for impermeability of the orogen. Oszczypko et al. (1981)
and Chowaniec et al. (1983) have determined the variability in
water-storage capacity with depth in the Magura and Krosno
Beds and have reported differences in the storage capacity of
these beds. The authors have found evidence that the thickness
of the permeable zone of the Krosno Beds in the Central Car-
pathian Depression reaches 40 m, which is only half of the
thickness of this zone in the Magura Beds. The filtration coef-
ficient of the Krosno Beds to the depth of 20 m is usually
m/s, while in the depth interval of 2040 m it is
m/s. Permeability in both the depth intervals of these
beds is one order of magnitude smaller than the permeability
of the Magura Beds. The permeability of the Krosno Beds in
the entire Carpathian Depression was studied earlier by Dzie-
In the region of Kojsówka, the substratum is built of medi-
um and massive sandstones with intercalations of clayey-mar-
ly shales belonging to the Lower and Upper Chocho³ów Beds.
Table 2: Results of fissuring measurements (after Ma³ecka &
Coefficient of fracturing
That is a fragment of the southern limb of the so-called Os-
trysz Syncline dipping northward according to Go³¹b (1959).
In the course of the planned siting of dam in Kojsówka, 18
boreholes have been drilled to depths of 4075 m to examine
water storage capacity. The results have been interpreted by
numerous authors (Michalik 1963; Monkiewicz 1966; Niedziel-
ski 1974). Table 3 presents specific water storage capacity at
In the region of Kojsówka no major dislocations have been
stated, however, the rock massif is strongly fractured, espe-
cially on the left slope. Following mining works, 220 cm
wide fractures, reaching to the depth of 6 m, have been detect-
ed. Fractures (13 cm wide) reach at least 10 m in depth. This
finding has been confirmed by water storage capacity tests.
According to the data presented in Table 3, it is apparent that
the impermeable zone has not been reached in each borehole.
The impermeable zone in the bottom of the valley and on the
right slope has been reached at a depth of 7075 m. Thus, a
thick zone of water holding rocks is observed here, especially
in the bottom of the valley, which is evidence of a deep infil-
The author of this paper has performed a statistical analysis
of the results of the water storage capacity of 18 boreholes
drilled in the Chocho³ów Beds near Kojsówka. The set of data
amounted to 293 (Table 4; Chowaniec 1989). Variability in
water storage capacity with depth has been approximated by a
logarithm function and by a polynomial function of n = 13
order (Fig. 3). The straight line reflects only a general trend in
the zones from which the majority of the data originate. The
Table 3: Specific water storage capacity of the Choch³ów Beds
near Kojsówka (after Monkiewicz 1966).
Specific water storage capacity (average)
Table 4: Statistical characteristics of specific water storage capacity.
Specific water storage capacity
Fig. 3. Specific water storage capacity versus ground water depth in
the Chocho³ów Beds in the region Kojsówka under the pressure of
Fig. 4. Specific water storage capacity versus ground water depth
order polynomial approximation (after Chowaniec 1989).
logarithmic curve is the most sensitive to any changes, thus, it
is the best approximation for changes in water storage capaci-
ty with depth.
In the case of the logarithmic function the curve with the
maximum (1.674) at the surface and minimum below 100 m
deep has been obtained. For the linear relationship, a straight
line crossing the ordinate axis at 81 m has been obtained. The
polynomial of 3
order has the minimum at the depth of 73 m.
The zone to the depth of 20 m is the most permeable. Specific
water storage capacity in this zone is above 0.5 dm
0.01 MPa. The zone at the depth of 2060 m, whose specific
water storage capacity decreases from 0.5 to 0.2 dm
0.01 MPa, is also well permeable. The third zone can be iden-
tified at the depth of 60100 m (Fig. 3).
The occurrence of these zones can be characterized by the
values of filtration coefficients, derived form water storage ca-
pacity, calculated according to the formula of Wieczysty
(1970) (Table 5).
The results obtained from statistical analysis have been
compared with the results of the studies performed for the
Magura and Krosno Beds of the Central Carpathian Depres-
sion. The thickness of the permeable zone of the Chocho³ów
Beds (80100 m) is similar to that of the permeable zone of
the Magura Beds and twice as thick as in the case of the Kros-
no Beds (Fig. 4). In Kojsówka the permeable zone features a
much stronger fissuring. The obtained results are similar to
the results for the sandstones of the Slovak Carpathian Flysch
reported by Jetel (1985). Here, in Kojsówka, the slightly larg-
Table 5: Mean filtration coefficient calculated on the basis of wa-
ter storage capacity.
Table 6: Thickness of the permeable zone in the Podhale Flysch
deposits based on the studies of water storage capacity.
1.88 ´ 10
6.08 ´ 10
1.74 ´ 10
5.71 ´ 10
coefficient k [m/s]
Kojsówka Chocho³ów Beds
5.71 ´ 10
(at 0.2 MPa)
6.21 ´ 10
30 (at 0.5 MPa)
3.19 ´ 10
15 (at 0.2 MPa)
2.43 ´ 10
20 (at 0.5 MPa)
2.43 ´ 10
er values for the permeable zone when compared to the Magu-
ra Beds are likely to be related to the tectonics of the Podhale
Flysch and the corresponding fissuring. In Podhale the joint
planes intersect the layers almost vertically and their number
increases in the zones of numerous faults.
HYDROGEOLOGICAL PROPERTIES OF THE PODHALE FLYSCH 81
Much lower values of water-storage capacity and a smaller
thickness of the permeable zone have been stated in the re-
gions of Szaflary (Drath et al. 1964; Oszczypko 1966) and
Jurgów (Bober et al. 1964). That is associated with the nature
of the deposits in these regions that is with the predomi-
nance of shales in the Szaflary Beds and in the beds from
Brzegi (Table 6).
For the flow of water in the flysch rocks the fractured and
permeable zone, with a maximum thickness of 100 m, is very
important. The thickness of this zone varies and depends
mainly on lithological development of the flysch deposits and
on their morphological position. This zone is thin (only 20
50 m), in the clay-shale of the Szaflary and Zakopane Beds,
and it is thicker in the sandstones of the Chocho³ów Beds (80
100 m). An increased fissuring of the rock massif is observed
especially in the zones of discontinuous dislocations, which
are preferable routes of water circulation, transport the largest
amount of water and play a draining function with respect to
water circulating in small fissures. Numerous joints and a
strong fissuring of the rocks results in a diversified water
By hydraulic analogy between water-injection into a bore-
hole and a well pumping, the following conclusions can be
drawn based on the obtained results. The average depth of the
wells drilled in a search for water should not exceed 50 m in
the shaly Szaflary and Zakopane Beds, and 100 m in the sand-
stone-shaly Chocho³ów Beds. Deeper wells can be drilled
only in strongly tectonized areas, where a thinner aquifer is
expected. Similar conclusions have been reported earlier on
the basis of Jetels (1985) studies performed in other parts of
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