Hydrogeology of the Ptuj field
Ptuj field is the plain stretching between Drava river, Slovenske gorice hills and the towns of Ptuj and Ormož. The field is filled with Quaternary gravel deposits with thickness varying from 4 to 22 meters. The Tertiary base of the Quaternary gravel deposits consists of conglomerate sand, clay and marl, with very low permeability. The underground water flows through the gravel deposits in the east direction, parallel to the Drava river. It is recharging from the precipitations and partly from the Drava river and discharging to numerous springs called Zvirenčine on foot of the high Quaternary gravel terrace. The Ormož town is supplied with drinking water from the wells on the eastern part of Ptuj field Quaternary gravel aquifer. The spillway water channel of the Formin hydroelectric power plant affected the underground water in a very low extent because all necessary interventions were made for the underground water protection.