ZAGROŻENIA DLA ZASOBÓW WÓD SŁODKICH NA WYSPIE UZNAM W ŚWIETLE BADAŃ MODELOWYCH I GEOFIZYCZNYCH

Abstract

HAZARDS OF FRESHWATER RESOURCES ON THE UZNAM ISLAND AFTER MODELLING AND GEOPHYSICAL INVESTIGATIONS

The study area is located in the north-eastern part of the Szczecin syncline. Almost entire area of Świnoujście is located on the Uznam Island, only the most western small part on the Wolin Island. The problems with potable water supplying is known for years. The possibility of the use of groundwater is strictly limited due to shallow appearance of salt waters that induces degradation of freshwater resources. The investigations were conducted to establish as well a flow system under modelling simulations as the zones of salt water ascension and intrusion under the geoelectrical tests. A numerical model was developed using Modflow package. It is evidenced that propagation of a cone of depression of the Wydrzany water intake causes an increased infiltration of surface waters from the Szczecin Lagoon. Additional geoelectrical imaging was done in 2006. The geoelectrical logging allowed to mark the interface line on the cross-sections. This logging, repeated at intervals of few years, proved the vertical and horizontal movement of interface surface between saline and fresh water.