Geologiczne uwarunkowania systemów krążenia wód podziemnych zlewni Krzny
Abstract
GEOLOGIC BACKGROUND OF UNDERGROUND WATER CIRCULATION SYSTEMS OF THE KRZNA CATCHMENT
Summary
There are three water-bearing stages in the Krzna catchment: Cretaceous, Tertiary and Quaternary ones, located within a zone of intensive exchange of underground waters. The Cretaceous stage forms, due to depression of its top and so increased depth northwestwards, the useful water- bearing horizon in the southeastern part of the Krzna catchment only. Tertiary and Quaternary deposits occur almost in the whole area of the catchment and their thickness increases northwestwards. The Tertiary stage is mainly composed of the Oligocene sandy sediments and the Miocene sandy-silty sediments. Pliocene clays occur locally. The Quaternary stage is composed of alternate clayey and sandy deposits.
A number of water-bearing horizons in these stages is varying but generally there are two: the Quaternary one with a free table and the Quaternary-Tertiary one with favorable filtration parameters and considerable thickness, with a confined table.
All these water-bearing horizons are recharged in plateaux. Their drainage occurs in river valley whereas depth depends on river discharge. The Krzna drains all the water-bearing horizons.
Summary
There are three water-bearing stages in the Krzna catchment: Cretaceous, Tertiary and Quaternary ones, located within a zone of intensive exchange of underground waters. The Cretaceous stage forms, due to depression of its top and so increased depth northwestwards, the useful water- bearing horizon in the southeastern part of the Krzna catchment only. Tertiary and Quaternary deposits occur almost in the whole area of the catchment and their thickness increases northwestwards. The Tertiary stage is mainly composed of the Oligocene sandy sediments and the Miocene sandy-silty sediments. Pliocene clays occur locally. The Quaternary stage is composed of alternate clayey and sandy deposits.
A number of water-bearing horizons in these stages is varying but generally there are two: the Quaternary one with a free table and the Quaternary-Tertiary one with favorable filtration parameters and considerable thickness, with a confined table.
All these water-bearing horizons are recharged in plateaux. Their drainage occurs in river valley whereas depth depends on river discharge. The Krzna drains all the water-bearing horizons.