Wykorzystanie niestacjonarnego modelu przepływu do oceny rzeczywistej wielkości eksploatacji wód podziemnych z piętra jurajsko-kredowego na obszarze intensywnych nawodnień rolniczych w rejonie Kalisza

Abstract

The usefulness of transient modeling method in quantification of actual groundwater abstraction out of Jurassic-Cretaceous aquifer within intensive irrigated areas near Kalisz.A b s t r a c t . The paper presents an increasing problem of uncontrolled groundwater extraction of the Jurassic-Cretaceous aquifer near Kalisz. Groundwater abstraction for irrigation purpose leads to a significant decrease in groundwater pressure in the northern reaches of the Kalisz district. Spatial and temporal analyses of the depression cone development made the author searching for a reason that would cause an ongoing decrease in the groundwater level of agriculturally utilized areas. Due to a significant range of Jurassic- Cretaceous piezometric pressure fluctuations, a transient model has been constructed to achieve this task. The model analysis indicates that the groundwater extraction of 1240 m3/h, required to make the piezometric field distribution compatible to field measurements, is to be 30% higher than recorded. Water abstraction may rise up to 1790 m3/h in the growing season and contribute to a progressive development of a regional depression crater as a consequence. Following the over-exploitation, the piezometric pressure of the Jurassic- Cretaceous basin has already been lowered by over 20.0 m in depth in the Blizanów community.