This paper describes how uncontrolled and illegal mining of sand and gravel can affect surface water and groundwater regimes in places where there is a hydraulic connection between them, based on a case study of the Velika Morava River in Serbia. Also, a change in cross-profile geometry, as a result of anthropogenic and natural factors, hinders the preparation of this river for inclusion among Serbia’s waterways. The Velika Morava River’s navigability would enable the development of waterborne transportation for both merchant ships and vessels of the Serbian Armed Forces River Flotilla. Correlations between water levels at gauging stations, as well as correlations between groundwater levels and river water levels at gauging stations, are used to show the dependence of these parameters on the change in the river bed profile after sand and gravel mining at the locations near gauging stations. In addition, the homogeneity of time-series of average annual elevations and the variance of the water levels of the Velika Morava River, measured in gauging stations during different periods, are statistically analyzed. The deepening of the Velika Morava riverbed where it was indiscriminately excavated in the 1980s led to the disruption of the groundwater regime and the hydraulic connection with the river, which lowered the water table of the aquifer used for the public water supply, as well as causing a number of other negative consequences.

Monitoring of water levels and flow rates of the Velika Morava River, due to its significance for the Republic of Serbia, was established over 100 years ago at the profiles of Ljubičevski Most and Ćuprija. This was followed a year later by the activation of the Varvarin monitoring station, then in 1935 by the Žabarski Most, and in 1952 by the Bagrdan station. Groundwater monitoring started in 1977 with 12 piezometers and the network was gradually expanded to include 92 piezometers in 2002. This study presents a comparative analysis of the water level elevations of the Velika Morava River and associated piezometers arranged along and normal to the river flow. Cross-correlation analysis was applied to evaluate the existing hydraulic connectivity between the Velika Morava River and the groundwater, with results used to calculate the average groundwater flow velocities within this section of the Velika Morava basin.