First of all as he uses to tell

							GSA 2007
Session T34 Regional Groundwater Flow in Honor of Joe Tóth
Hydrogeology

From Paradigm to Paradigm or From Tóth to Tóth in Hungary’s
Hydrogeology
by Judit Szőnyi-Mádl
1/C. stny. Pázmány,      Budapest   1117,   Tel:   0036   13812129,   Fax:   0036   13812130,
szjudit@ludens.elte.hu


Keywords: paradigm, flow systems, József Tóth, Great Hungarian Plain


Introduction
In 1988 Mihály Erdélyi, a Hungarian hydrogeologist revealed me the famous, just
now celebrated 45 years old paper of Joe Tóth. This paper opened a new world
in my mind. Through local aspects a broader coherency unfolded me in
hydrogeology. It seems a great challenge to come to know this new approach
and apply it for groundwater’s in Hungary. That time the shifts of paradigm in
hydrogeology on the international level were far away from the Hungarian
special public, either way I was fortunate enough because I met Jóska at 1994.
Since that we have been working together. For two years he has been honorary
professor at the Department of General and Applied Geology of Eötvös Loránd
University, Budapest.

Goals of the study
In this presentation I undertake to answer the question, what is the influence of
Tóth’s personally and his regional groundwater flow theory indirectly on the
evolution of paradigms of the groundwater flow beneath the Great Hungarian
Plain. The display of his Hungarian activity would add new data for the cognition
of his pursuit.
Evolution of knowledge on the flow systems of Hungary befell in four stages. The
first is independent from Tóth; the second can be related to his 1962-63 papers
and the third and fourth are connected to his work in Hungary.

The 1st Paradigm
The first stage is represented by Hungarian hydrogeologists, Schmidt Eligius
(1962), Urbancsek (1963) and Rónai (1963).
On the Figure 1 the profile' s of Rónai (1963) displays the topography contours,
the pressure heads, additionally the depth of water level and temperature data,
as well as the direction of vertical flux can be seen. Nevertheless the correlation
between high and low topography, vertical flux component and temperature can
be recognized from this early section.
                     Figure 1 (modified after Rónai, 1963)


These early studies were limited to a depth of 400 m, recognized the correlation
of down- and up-ward flow with high and low topography, but did not produce a
model for the observed pattern. Therefore the artesian paradigm was maintained
henceforward.

The 2nd Paradigm
Tóth’s activity in Hungarian hydrogeology started with his letter to Rónai in 1963.
This document confirms at first that based on Rónai’s earlier cited study Tóth
recognized the similarity between the Pannonian Basin and the Canadian Prairie.
Secondly he found that his general theories are valid for the Great Plain as well.
The continuation issued from Erdélyi who wrote to Tóth in 1971 and sent him his
manuscript about Hydrodynamics of the Pannonian Basin. Erdélyi summarized his
results in a peculiar profile (Figure 2) on which he used a logarithmic vertical
scale to enhance the details of flow-pattern geometry at shallow depths while
avoiding the questions of distribution and origin of deep overpressures. He wrote
to Tóth in his letter: "I feel that based on a huge amount of field data, I have
succeeded to verify and further develop your flow-system concept for a large
basin."
                    Figure 2 (modified after Erdélyi, 1972)

Based on the proceedings it can be concluded that the Great Hungarian Plain
provides an empirical evidence for Tóth’s flow-system model. The gravitational
driving force was recognized for the upper parts of the basin. However the cause
of the deep overpressures remained unknown. Due to this phase a new dynamic
paradigm was born in Hungarian hydrogeology.


The 3rd Stage
The third stage is due to Tóth and Almási's study in 2001. It based on over
16 000 fluid-potential data from between a few to over 3000 m depth. As a
matter of fact they found two principal driving forces for fluid flow in the
Pannonian Basin. One of them is due to elevation differences of the topographic
relief and the other is a consequence of tectonic compression in the deep part of
the basin (Figure 3). The Great Plain is under the influence of the tectonic
compression which is proved by intraplate crustal velocities data for the
Pannonian Basin.
                Figure 3 (modified after Tóth and Almási, 2001)

This overpressured regime is confined whereas the meteoric regime is
unconfined. It was found that the nature and the geometry of the transition
between the two regimes are controlled by sedimentary windows, conductive
faults. This paradigm gave a data controlled new conceptual model for the flow-
system of the Great Hungarian Plain.


The 4th Stage
The fourth stage was produced together by ELTE staff for the Duna-Tisza
Interfluve (DTI) through lots of studies. The goals of these studies were to refine
the results of the previous study and to answer the questions what is the source
of the salts on the area and what controls are on the distribution of the
ecologically different regions.
Based on these studies Tóth and Almási (2001)'s conclusions could be confirmed.
The gravity-flow systems are perched on ubiquitously ascending waters; vertical
flow occurs through conductive faults and between rock grains. These faults
could be derived from seismic section interpretation. The vertical flow in the two
regimes is opposite beneath the highlands and upwards in the depressions. It
was also recognized that the salts originate from the basement and are
distributed by groundwater discharge controlled by the interplay between the
gravitational and overpressured systems.
From the generally valid results of these studies a hydrogeological schematics
the so called Type Section was deduced for the Duna-Tisza Interfluve (Figure
4). On this profile it can be seen that the ascent of the deep waters combined
with the gravitational system’s geometry explains the pattern of soil salinization
and the contrasting chemistry between saline-type and fresh-water wetlands.




                                     Figure 4

Epilogue
„The love of science, the creative urge, the devotion to scientific standards…”
This sentence after one of Tóth’s favorite author Michael Polanyi characterizes
his scientific personality. The common research work in Hungary together with
Tóth is in progress. Anyway it can ask why is the world famous Professor in
Hungary? I suppose the answer is doubtful for him, but I try to imagine it. First
of all as he uses to tell: „The Pannonian Basin is a Natural Research Lab to study
Groundwater Flow Systems” and there are lots of interesting things here for
understanding. This field lab is his birth place as well, he has here nice students
and there is a nice place at the university for further work. At last but not least I
suppose that he prefers the enjoyable Hungarian life style.