The Danube Basin (Austria-Hungary-Slovakia)
Recommendations for sustainable management of transboundary
hydrogeothermal resources at cross-border pilot areas
Radovan Černák, Jaromír Švasta
ŠGÚDŠ, Mlynská dolina 1, Bratislava
Contents
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Introduction to the Danube Basin Pilot Area

Geographical and socio-economic aspects
 Hydrogeological overview
 Geothermal Overview
 Utilization of geothermal water
•
Present and future hydrogeothermal resources
 Modeling results
 Evaluation of sustainability of current use of thermal ground water
 Recommendations for monitoring areas
Geographical and socio-economic aspects
 Total investigated area:
cca 12 400 km² (HU:40%, SK:51%, AT: 9%)
 Moderate population density:
50 – 300 inhab. per km2
 Mayor cities (inhabitants):
Bratislava – 420 000
Trnava –
66 000
Komárno – 35 000
Nové Zámky – 40 000
Dunajská Streda –
23 000
Győr –
132 000
Mosonmagyaróvár –
35 000
Komárom– 20 000
Sopron –
56 000
Pápa –
35 000
Neusiedl am See 10 000
 Industrial zones: Bratislava, Komárno,
Komárom, Győr
 High share of agricultural activities
Geological overview - Danube Basin
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several depocenters / various age - depressions surrounded
by mountains
the depth of the basin > 8500 m - central part of the basin Gabcikovo depression
The Pre-Tertiary basement - crystalline and mainly late
Paleozoic and Mesozoic (dominantly Triassic – Jurassic)
sedimentary seqences
Tertiary rocks - sandstones, marls and clays as well as coal
or bauxite occurrences
Badenian, Sarmatian sediments - clays, siltstones,
conglomerates, sandstones
Lower Pannonian - shallow water to lacustrine sediments clays, sands, gravels
Upper Pannonian and Pliocene sediments - deltaic and
fluvial facies
parts of the Upper Pannonian also basaltic volcanism
Quaternary deposits - Fluvial deposits +loess - thickness 600 m Gabcikovo depression
Hydrogeological conditions - Danube Basin
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The crystalline basement has no significant - groundwater flow system
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Mesozoic aquifer system of the Danube Range blocks of carboniferous basement – limestones/dolomites
– favourable hydraulic conditions, sometimes in connection of overlying sedimentary fill of the basin
(Badenian sediments)
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The Miocene sedimentary aquifers (Badenian or Sarmatian sands and limestones) are connected to the
basement aquifers and form a single flow system. They content fossil waters with high salinity
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The Upper Miocene and Lower Pannonian - low permeable and thick marl and clay sequences = regional
aquicludes
• separate the flow system of the basement from the deep (usually thermal water) flow system of the
porous formations characterized the Pannonian reservoir.
Hydrogeological conditions - Danube Basin
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Upper Pannonian formation - interlayer leakage, intergranular permeability and confined groundwater level,
thermal waters 42–92 °C, sands to sandstones aquifers.
• towards the center of the basin the number of sandstone aquifer layers and thickness increases
• towards the center of the basin porosity and permeability decrease
• the sandy aquifer layers vary with aquitard clay, sandy clay layers
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Quaternary sediments - unconfined reservoir, cold groundwater with hydraulic connection with the
Pannonian flow systems, groundwater regime depends on the Danube river
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With respect to lithology, the aquifer and overlying beds have been divided into six hydrogeological
complexes. Each represents a complex with different ratio of aquifers and aquicludes. The waters in the
Central depression are either marinogenic or petrogenic and are divided into five chemical types
Geothermal conditions
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Temperatures at the depth
2500 m – 75 °C – 120 °C
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Influence by the
surrounding mountains
and basin subsindence
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Moderate HFD conditions
– 70 – 100 mW/m2
Utilization of geothermal water
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utilization of geothermal water - pumping + natural overflow form wells
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average yield of utilized geothermal water on Hungarian side of the Danube basin
4 005 221 m3/year, 78 wells utilized, average well utilization 51 349 m3/year/well
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average yield of utilized geothermal water on Slovak side of the Danube basin
2 891 818 m3/year, 33 wells utilized, average well utilization 87 631 m3/year/well
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active user of geothermal water on Austrian side of the Danube basin
(Frauenkirchen) – no data available
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use: bathing and balneology, heating (greenhouse and district)
For the evaluation in the project TRANSENERGY
– geoscientific modelling on supraregion and pilot areas with different scales
Tasks for the Hydogeological and Geothermal models or the Danube basin :
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Evaluation of sustainability of current use of thermal ground water
Calculate the water budgets in transboundary flows
Estimate the power and energy stored
Show the potential transboundary areas that might be affected in
future and give monitoring recomnedations
 Give the recomendation for future utization
Source of information:
• Common databases compiled for the purpose of the project
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Geological model of the supraregion and pilot areas
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Hydogeological and Geothermal model supra region
 Description of the overall hydraulic conditions and regional flow
systems
 Description of the overall geothermal conditions
 Estimation of existing geothermal potentials
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Reservoir delineation
Evaluation of sustainability of current use of thermal ground
water by hydraulic and geothermal models
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simulate the hydrogeological and geothermal conditions (steady state model) - preNeogene and Neogene fill of the Danube basin - focused on Upper Pannonian
geothermal aquifers
- compared in the model
- pre-utilization reflecting “natural conditions” with no pumping assumption
- assumption considering influence of the production wells based on geothermal
water extractions reported - years 2007-2010
The vertical extent 10,000 m a.s.l.
Vertical resolution
The model adopted a geological model consisting of 8
hydrostratigraphic units:
Quaternary - phreatic
Upper Pannonian
Lower Pannonian
Sarmatian
Badenian
Badenian volcanites
Cenozoic
Mesozoic, Paleozoic and Crystalline basement
Hydraulic and geothermal models
Flow boundary conditions
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outer limit of the model follows natural hydrogeological
boundaries - defined by extend of thermal water bearing
horizons or by groundwater divides - no-flow boundary
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all across the top surface constant groundwater head groundwater potential of cold water Quaternary aquifers
laying on top of thermal aquifers
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utilization variant - average reported well yields from 2007
– 2010 assigned as pumping rates
Heat boundary conditions
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at the base of the model - constant heat flux
(mW/m2), Lenkey, 2012
at the ground surface uniform temperature 10 °C
radiogenic heat production in rocks
Hydraulic and geothermal models - RESULTS
model - numerical representation of hydrological and geothermal characteristics of the pilot
area
 model effects of wells utilization –
pressure changes
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theoretical infinite pumping of all existing
operating geothermal wells
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decrease of the pressures caused by
pumping of the rates (as reported for the
years 2007 – 2011) is negligible on
regional scale
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Decrease of the pressures is on pumped
wells and has local efect
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Changes in pressures in deeper horizons
are subtle and are caused by change of
water density as a decrease of water
temperature casued by pumping
-1000 m a.s.l
-2000 m a.s.l
-3000 m a.s.l
-5000 m a.s.l
Pressure differences (Pa) caused by steady pumping at different depth levels
Hydraulic and geothermal models - RESULTS
 model effects of wells utilization –Temperature distribution
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convection - high importance for heat transport
• in karstified Mesozoic carbonate - Komárno elevated block
• relatively intensive water interchange between recharge and
discharge zones in Quaternary sediments
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- 1000 m a.s.l
considerable cooling of the whole carbonate massive in Komarno
elevated block
cooling effect of thick quaternary aquifer in the central part, large
depth (up to 600 m), rapid circulation of 10˚C ground water (high
permeability) across the whole thickness of the quaternary gravels
and sands
cooling propagates to large depths over 3 km
Difference in temperature - pre-utilization state vs. steady pumping
scenario at the basement of Upper Pannonian
-2000 m a.s.l
- 3000 m a.s.l
Hydraulic and geothermal models - RESULTS
Transboundary aspects evaluation
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computed flow trajectories with travel times,
induced by pumping in utilized thermal wells
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significant amounts of water and energy
moving either naturally or by forced
convection from state to state
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international cooperation in managing
geothermal resources needed
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lateral extend of well capture zones may be
underestimated, in model homogeneous
aquifers, in reality predominantly from more
permeable layers
Transboundary Darcy flux - whole domain except quaternary [l/s]
Transboundary Darcy flux - Pannonian [l/s]
30
20
HU, pumping
HU, pumping
15
20
HU
Outflow [-] to / inflow [+] from respective country
HU
HU, pumping
HU
5
AT
AT, pumping
0
SK
-5
SK, pumping
AT
-10
-15
-20
AT, pumping
Outflow [-] to / inflow [+] from respective country
HU
10
HU, pumping
10
AT
AT, pumping
0
SK
-10
SK, pumping
AT
-20
-30
-40
-50
-25
SK
SK
SK, pumping
SK, pumping
-60
-30
HU
AT
Budgeted country
SK
HU
AT
Budge te d country
SK
AT, pumping
Hydraulic and geothermal models - RESULTS
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amount of thermal energy contained in porous rock and pore water filling (Specific Identified
Resources) of upper Pannonian hydraulic unit (including aqiufers and aquicludes)
portion of heat stored that can be theoreticay excavated raising from the egde of the basin to
the centre, reaching up to 140 GJ/m2
Balance of the renewable thermal
enegy
• Actual utilization in geothemal
wells is small in comparision to
thermal power of the Danube
basin model
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Still potential for sustainable
geothermal energy utilization
450
400
350
Thermal power [MW]
300
250
Geothermal w ells
Radiogenic heat inflow
Deep heat inflow
200
150
100
50
0
HU
AT
SK
Proposal for transboundary monitoring in Danube Basin
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the main reservoir of Danube Basin represents the Upper Pannonian formation, the dish-like
shape and brachysynclinal structure of depression,
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contains thermal waters 42–92 °C warm which are bound mainly to sands to sandstones
aquifers
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possibility decrease of temperature due to infinite pumping (color) and piesometric head
contours at the base of upper Pannonian at natural state (black, m a.s.l.)
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recommendations for establishment of groundwater monitoring - necessary for a long-term,
effective water management both quantitative and chemical (quality) monitoring
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proposed monitoring areas (red)
Proposal for transboundary monitoring in Danube Basin
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thermal waters are bound to upper Pannonian aquifer,
extending on both sides of the border river Danube at
depths from 1000 to 2500 m
thermal waters are utilized by a number wells, almost
solely for recreational purposes
proposed extend of monitoring Mosonmagyaróvár –
Lipót – Šamorín (310 km2)
advisable to set up at least 2 new monitoring wells between
Mosonmagyaróvár and Šamorín, use existing currently non
operated wells FGČ-1, BL-1 and FGGa-1
monitored parameters - minimum well head pressure and
reservoir temperature, sampled on weekly basis
Proposal for transboundary monitoring in Danube Basin
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of upper Pannonian thermal aquifer between Gyõr and
Veľký Meder used for bathing
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proposed extend of monitoring Area 2 Gyõr – Veľký
Meder (315 km2)
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area close to river Danube – no hydrogeological
boreholes - recommended 2 monitoring boreholes
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currently unused wells VZO-14 and VČR-16 can be
easily converted into monitoring boreholes
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monitored parameters - minimum well head pressure
and reservoir temperature, sampled on weekly basis
Thank You for attention!
ŠGÚDŠ
ŠVASTA Jaromír
REMŠÍK Anton
ČERNÁK Radovan
MFGI
TÓTH Gyuri
SZALKAI Ágnes Rotár
GBA
GOETZL Gregor