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.

In order to successfully steer a ship, a man, ship’s watch officer, or commander of the ship must be physically ready and must know the maneuvering characteristics of the ship he steers, as well as the forces acting on him. For that, it is necessary for him to know the specifics of the ship because each ship has its own "mood", its specific properties that depend on the type, and size of the ship. Therefore, maneuvering properties differ even in ships of the same type and therefore it is important to know the specifics of a particular ship. Also, the same ship will behave differently in different situations. When the ship finds itself in situations that require urgent reaction during the voyage, then the experience and skills of the ship's captain come to the fore. Then it is important that the captain, based on his experience, chooses the right maneuver, but also that he always has at least one reserve maneuver in his head. That decision in certain situations must be made in a very short period of time, and the future of the ship and human lives often depends on it, as well as the resources on board. Every skill is acquired through practice, and it is logical that the commander will react faster and more correctly in every new situation. Precisely because of this, the most intensive training is necessary for the formation of quality ship commanders. For that reason, the training of future ship commanders on ship simulators gives excellent results. On ship simulators, they can gain a lot of experience and go through countless scenarios. In this paper, the use-value of ship simulators from the aspect of the training was verified through the Search and Rescue (SAR) exercise realized on the ship simulator Wärtsilä Navigation Simulator NTPRO 5000. It has been shown that the simulator can successfully check and recognize the optimal SAR pattern, maneuvering characteristics of the ship, as well as practice, maneuvering the ship and resolving specific situations that ship commanders may encounter in real situations. Training on ship simulators cannot completely replace training in real situations, but it can be used to get acquainted with the maneuvering characteristics of the ship, train in working with navigation devices, and be a good starting point in preparing people who are trained to perform tasks in real situations. The use of hydrological data of relationships between different types of data using an autoregressive model (AR model) can contribute to the creation of more realistic scenarios on ship simulators. It is also possible to apply data in the modeling of the environment and connect them with the current hydrological situation of the waterway. In the exercise evaluation process, we can see if the ship's captain used the hydrological data in the right way.

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.

Ports and wharves are essential parts of the infrastructure that enable the transport of goods on inland waterways. Integrating the network of inland waterways and land modes of transport, the ports are the main hubs of the transport network, they encourage economic activities and enable the development of the region. The port of

Introduction/aim: This paper aims to present the methodology for creating educational content/scenarios on a ship simulator (bridge simulator) that will serve officers of river units in developing the ability to react when performing regular and military tactical tasks on the ships of the River Flotilla. Also, training on the simulator aims to train officers of river units using modern information technologies. Methods: The paper uses simulation methods, experimental methods, case studies, and operational research. Results: Specific educational content/scenarios were created, also specific methodology was developed and the principles were clearly defined according to which content/scenarios are created on the ship simulator. Conclusion: By using the ship simulator, in different teaching scenarios, cadets of river units as well as members of river units are trained and acquire the ability to react adequately in real situations in the shortest possible time.

The Velika Morava represents the largest river basin in the Republic of Serbia, with a total area of 37,444 km², of which 36,163 km² belongs to Serbia, accounting for 42.38 % of its total territory. In its lower course, it is a typical lowland river that frequently changes the geometry of its riverbed under the influence of natural and anthropogenic factors, which poses a major problem for the establishment of river navigation. River navigation on this river was established at the beginning of the 19th century, when the first steamboat arrived in Stalać, and during that period it was used exclusively for tourism purposes. Today, only the last 15 km of its course are navigable for the vessels of the River Flotilla in the execution of assigned tasks. However, the river flow itself and its hydraulic connection with groundwater formed in the alluvium of this river are of exceptional importance for the water supply of the population and industry, for agricultural purposes (irrigation), as well as for the extraction of sand and gravel from the riverbanks and the riverbed itself. The paper will present an analysis of natural and anthropogenic factors using statistical methods, as well as an assessment of their impact on the geometry of the river course, the regime of surface and groundwater, and, in this regard, the utilization of this natural resource for various purposes.