Hydrogeological conditions of hydrogeological area 4232 Ústí syncline in the drainage basin of the Svitava river from the point of view of groundwater formation as a source of drinking water

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F23%3A10168931" target="_blank" >RIV/00025798:_____/23:10168931 - isvavai.cz</a>

Result on the web

<a href="https://journals.muni.cz/gvms/article/view/36977/31997" target="_blank" >https://journals.muni.cz/gvms/article/view/36977/31997</a>

DOI - Digital Object Identifier

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Result language

čeština

Original language name

Hydrogeologické poměry hydrogeologického rajonu 4232 Ústecká synklinála v povodí Svitavy z hlediska tvorby podzemní vody jako zdroje vody pitné

Original language description

Hydrogeological area 4232 Ústí syncline in the drainage basin of the Svitava river is producing very significant amounts of underground water. This water has been used as drinking water since 1914 for the Brno agglomeration. Two hydrogeological structures are exploited: aquifer C (Jizera formation) and aquifer B (Bílá hora formation). The Ústí syncline represents an asymmetrical graben, the deepest part of which is delineated by the Semanín and Svitava faults. The underground water of both structures is replenished by rainfall in the areas where they crop-out, namely in the eastern flank of the whole syncline. Systematical monitoring of the quality of the underground water has been running in the area for a very long time. It comprises mainly monitoring of the water quality in the individual production areas and monitoring of wells of the Czech Hydrometeorological Institute. Evaluation of all these data showed, that the whole area of the Ústí syncline, but especially the aquifer C, is threatened by areal pollution by nitrate compounds and locally by pesticide metabolites. Nitrate content reach up to 40 mg/l, which is the limit concentration set by the regulation 252/2004 Sb. Pesticides locally exceed the limit concentration. This shows, that the most dangerous compounds for the underground water as potential contaminants are clearly compounds closely connected with agriculture. The introduction of potential contaminants is of course controlled by the hydrogeological properties of rocks, i.e. whether it is a reservoir rock or a sealing rock. Sandstones of the aquifer C are separated by a layer of marl, sometimes called the Ca/Cb aquiclude. However, in the near-surface zone and in outcrops, this marl is heavily fractured and is very permeable. The Ústí syncline is also known for several pseudo-karst caves. Moreover, deeper pseudo-karst caverns were penetrated by boreholes by accident during the exploration of the Semanín fault zone. This karst permeability enables rapid spreading of infiltrating compounds including all possible pollutants. Based on tritium activity, freons and SF6 measurements, the mean delay times of the underground water in the Ústí syncline is estimated to be the first tens of years. One cannot presume any natural attenuation of very stable pesticides metabolites, just dilution. Based on this, there is a very real risk, that with increasing share of underground water younger than 2010, which has much higher concentration of pollutants, the concentration of these compounds will increase in exploited underground water.

Czech name

Hydrogeologické poměry hydrogeologického rajonu 4232 Ústecká synklinála v povodí Svitavy z hlediska tvorby podzemní vody jako zdroje vody pitné

Czech description

Hydrogeological area 4232 Ústí syncline in the drainage basin of the Svitava river is producing very significant amounts of underground water. This water has been used as drinking water since 1914 for the Brno agglomeration. Two hydrogeological structures are exploited: aquifer C (Jizera formation) and aquifer B (Bílá hora formation). The Ústí syncline represents an asymmetrical graben, the deepest part of which is delineated by the Semanín and Svitava faults. The underground water of both structures is replenished by rainfall in the areas where they crop-out, namely in the eastern flank of the whole syncline. Systematical monitoring of the quality of the underground water has been running in the area for a very long time. It comprises mainly monitoring of the water quality in the individual production areas and monitoring of wells of the Czech Hydrometeorological Institute. Evaluation of all these data showed, that the whole area of the Ústí syncline, but especially the aquifer C, is threatened by areal pollution by nitrate compounds and locally by pesticide metabolites. Nitrate content reach up to 40 mg/l, which is the limit concentration set by the regulation 252/2004 Sb. Pesticides locally exceed the limit concentration. This shows, that the most dangerous compounds for the underground water as potential contaminants are clearly compounds closely connected with agriculture. The introduction of potential contaminants is of course controlled by the hydrogeological properties of rocks, i.e. whether it is a reservoir rock or a sealing rock. Sandstones of the aquifer C are separated by a layer of marl, sometimes called the Ca/Cb aquiclude. However, in the near-surface zone and in outcrops, this marl is heavily fractured and is very permeable. The Ústí syncline is also known for several pseudo-karst caves. Moreover, deeper pseudo-karst caverns were penetrated by boreholes by accident during the exploration of the Semanín fault zone. This karst permeability enables rapid spreading of infiltrating compounds including all possible pollutants. Based on tritium activity, freons and SF6 measurements, the mean delay times of the underground water in the Ústí syncline is estimated to be the first tens of years. One cannot presume any natural attenuation of very stable pesticides metabolites, just dilution. Based on this, there is a very real risk, that with increasing share of underground water younger than 2010, which has much higher concentration of pollutants, the concentration of these compounds will increase in exploited underground water.

Type

J_SC - Article in a specialist periodical, which is included in the SCOPUS database

CEP classification

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OECD FORD branch

10505 - Geology

Project

<a href="/en/project/SS06010044" target="_blank" >SS06010044: Defining and evaluating the areas decisive for subsidizing strategic groundwater resources with regard to their protection and stabilization</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2023

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Geological Research in Moravia and Silesia

ISSN

2336-4378

e-ISSN

2336-4378

Volume of the periodical

30

Issue of the periodical within the volume

1-2

Country of publishing house

CZ - CZECH REPUBLIC

Number of pages

7

Pages from-to

66-72

UT code for WoS article

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EID of the result in the Scopus database

2-s2.0-85183992713