Parti szűrésű vízbázisok vízföldtani vizsgálata a Duna magyarországi szakaszán
Authors: Nyiri Gábor , Fekete Zsombor , Kolencsikné Tóth Andrea , Madarász Tamás , Zákányi Balázs , Turai Endre , Nádasi Endre_Kázmér , Szűcs Péter 
Published: June 2024

Összefoglalás.

Jelen tanulmányunkban két Duna menti parti szűrésű vízbázis vizsgálatát tűztük ki
célul. A Tiszta Ivóvíz: a biztonságos ellátás multidiszciplináris értékelése a
forrástól a fogyasztóig című Nemzeti Kiválósági Program keretében két olyan
kiemelt fontosságú parti szűrésű vízbázist vizsgáltunk, amelyek meghatározó
szerepet játszanak a Fővárosi Vízművek ellátási területén, Budapesten.
Választásunk a Szentendrei-szigeten található surányi vízbázisra, valamint a
Csepel-szigeten található ráckevei vízbázisra esett. A két vízbázis
vizsgálatának célja az volt, hogy a területen végzett terepi mérések és
mintavételezések, valamint a modellezési szimulációk segítségével átfogó képet
kapjunk ezen két terület hidrogeológiai viszonyairól, hidraulikai
viselkedéséről. Ennek érdekében számos terepi mérést végeztünk, amelyek fontos
adatokat szolgáltattak a két vízbázis hidrodinamikai modelljének felépítéséhez
és kalibrációjához.

Summary.

In this study, we dealt with two significant riverbank filtration systems along
the Danube: the Surány water base located on Szentendre Island and the Ráckeve
water base located on Csepel Island. These are two important drinking water
bases of the Budapest Water Works, which provide a significant proportion of the
capital’s water needs and are of great importance from the point of view of
water security. At these riverbank filtered water bases, water is produced with
horizontal collector wells, which, thanks to their design, are capable of
extracting large amounts of raw water. The aim of our work was to get to know
the geological and hydrogeological conditions of the area using the tools of
field measurements and geophysical measurements. To this end, we measured the
following parameters in different temporal resolutions: water level,
temperature, specific electrical conductivity, pH. In this study, we present the
results that have more significant information. Geophysical tests were also
carried out at the two water bases, which provided important information
regarding the geological inhomogeneity. Using the field measurements, two
hydrodynamic model was also built for each study area. Our field measurements
were also a great help for the calibration of our model. In this study the
calibration of these models was shown. The hydrodynamic models were performed in
the modeling environment of the Groundwater Modeling System, using the MODFLOW
code. The characteristic of the model is that the tentacle wells were defined
using MODFLOW’s Revised Multi-Node Well package. With the help of these models
we would like to determine the arrival times in the future, as well as examine
different scenarios that can be linked to extreme weather conditions. Based on
the field measurements, we can make the following main conclusions regarding the
examined water bases:

During the entire period of the year, the hydraulic gradient from the
Danube side is greater than from the background direction. Based on
this, we can say that the Danube is the dominant supply water source
in both cases.

The hydraulic gradient changes over time, which is constantly
influenced by changes in the water level of the Danube and changes
in the produced yields.

As the hydraulic gradient changes, the speed of the water flow also
changes, so the access time changes from time to time, even from day
to day.

The specific electrical conductivity measurements showed that the
Danube’s flood causes a large decrease in the value of the specific
conductivity in the northern area. In addition to the decrease in
conductivity, the measurement results also show a time shift, which,
does not necessarily show the value of the access time.

Based on geophysical measurements, it can be said that the Ráckeve
water base has greater inhomogeneity than the Surány water base. As
a result, the zonal calibration of the hydrodynamic model of the
Ráckeve water base became necessary.