engleski

Identification of the dominant recharge discharge effects of the Zagreb alluvial aquifer

River-aquifer interaction between the Sava River and the Zagreb aquifer was analysed using comparison of duration curves of the Sava river stage and aquifer ground water levels. Analyses showed the percentage of time river stage exceeded groundwater levels’ pointing at dominant aquifer recharge effects as well as percentage of time river stage was below the ground water levels pointing at dominant aquifer discharge effects. 10-year time series of the river stage measured on 9 gauging stations and ground water levels measured in 45 piezometers in a near vicinity of the river were analysed in a 22 cross-sections along the Sava river course, which were defined based on a flow net analysis. Analysis was primarily aimed at determining dominant aquifer recharge discharge effects along the course of the river Sava, using duration curves created from 10-year river stage and aquifer ground water levels time series data sets. Recharge discharge effects were also analysed using duration curves created from a yearly time series data sets in order to identify changes in aquifer recharge discharge during specific hydrological conditions, namely drought and wet hydrological years. Besides, the analysis was also pointed to identification of the river stages at which changes between recharge and discharge mainly occur. Results based on a 10-year time series analysis showed variations in aquifer recharge discharge effects along the course of the river Sava without pointing out to overall domination of either aquifer recharge or discharge. On the other hand, yearly analysis pointed out to several years with pronounced aquifer discharge effects, i.e. 2003, 2011 and 2012 as well as aquifer recharge effects, i.e. 2004, 2005 and 2008. Analysis contributes to conclusions that further management of the river Sava, the dominant boundary condition of the Zagreb aquifer system, should comprise its regulation using weirs or dams in order to prevent potential water supply shortages during drought hydrological years

river-aquifer interaction; recharge discharge effects

nije evidentirano