engleski

Modelling groundwater recharge in the Osijek area, Eastern Croatia.

The importance of water resources in water supplying especially the importance of groundwater is of an exceptional interest to an expert and scientific community. There is a general trend of increased demands in water consumption which focuses on the issue of possible groundwater regeneration in some areas since 90% of water demands in the Republic of Croatia is supplied by the exploitation of groundwater. Within the framework of this work the attention was directed towards alluvial water bearing complex of a distinct heterogeneity, out of which water is being intensively exploited, with relatively numerous data on bearing of gorundwater under exploitation conditions. As a research area Osijek pumping site Vinogradi was chosen as an example of heterogeneous water bearing system of a regional importance. The aims of the research were the study of a multiple exploitation of the available data of polidisciplinary sources on properties of certain layeres and an area of their significance and analysis of the interpretation methods as well as the issue of the reconstruction state and recovery of groundwater supplies. The research was directed to state variant solutions based on the model of groundwater flow developed through the usage of GMS software package which give qiuck answers to various scenarious of conditions of groundwater regeneration and demands for their exploitation in water economy. In setting up the valid groundwater flow model, special attention was aimed at aquifer heterogeneity both according to its lithologic structure and according to the relation between porous and semiporous layers. The paper also deals with the issue of identification hydraulic continiuty and the credibility of the analytical interpretation of parameters as well as boundary conditions of heterogeneous aquifer, then the developement of the processing procedure in pumping test of leaky aquifer during the change of water level in source layer as well as the effect identification of intense pumping on the change in regional water balance and recovery of groundwater supplies in eastern Podravina. With reference to former mathematical modelling, a model of regional flow of groundwater was shown during the operation of pumping sites in Vinogradi by using a multipurpose programme package GMS. Its application was directed to the verification of the effects of groundwater regeneration as well as the efficiency of the model while researching hydrogeologic phenomena in magnified range of scale. After showing the very programme package and perimetric conditions, it is stressed that the efficiency of calibration for the period of longterm pumping, depends by large on the reality of the size of waterbearing system regeneration. The groundwater recharge was divided into two categories. The first is in the central space and surrounds the pumping site and counts for 11, 5% of annual precipitation. In the outer band the calibration was carried out by fourfold less figure of effective recharge of aquitard package of layers. In reality the distribution is by large more continued than the amount bigger than the average of the inner band up to the value of zero in the area of perimetric watershed where during the average hydrologic year there is not a noticeable change in groundwater supplies. Approximately double increase of abundance of exploited quantities within the area of this model would generate the effect which would disrupt the state in model boundaries so strongly that it would cause the disruption of the regional balance of groundwater.

groundwater modelling, water supply, regional flow

nije evidentirano