In this research, the SWAT+ model was employed to elucidate hydrological dynamics within the Beas Basin. The primary objectives encompassed the calibration of the SWAT model for accurate water balance quantification, annual simulation of salient hydrological components, and a decadal analysis of trends in fluvial discharge and sediment transport. The methodology encompasses simulating hydrological data with the SWAT+ model, followed by calibration and validation using flow data from Larji and Mahadev hydroelectric plants. The model’s efficacy in depicting streamflow and other hydrological components is corroborated by statistical measures such as the Nash–Sutcliffe efficiency and PBIAS. The water balance analysis delivers insights into the basin’s hydrological characteristics, including surface flow, water yield, and evapotranspiration. The temporal analysis exposes intricate seasonal and interannual variability in flow and sediment discharge, while spatial distribution highlights heterogeneity across the basin. These findings have practical implications for water resource management, including optimizing water allocation, hydroelectric power generation, irrigation, and environmental concerns. Limitations, such as data quality and model simplifications, are acknowledged, and future data collection and observations are recommended for improved model performance. In essence, these researches enhance understanding of the Beas Basin’s hydrology, setting a course for future investigations to integrate more data sources, refine model parameters, and consider climate and land-use changes for a richer comprehension of the basin’s hydrological dynamics.

Concerning the media’s properties, there is always a possibility of changing groundwater flow conditions surrounding hydroelectric power plants. Causes for such events could be natural or anthropogenic, which is, in many cases, not so obvious to determine. In addition, determining a period when changes in the groundwater flow occur is a complex task. All of the above mentioned are of crucial importance due to the operational work of hydropower plants, i.e., the optimization of the inflow and outflow of the water in the turbine, regardless of the hydropower plant type. All types listed require a particular approach for solving such issues. Rescaled Adjusted Partial Sums (RAPS) is an appropriate time-series analysis method. In this specific case, observed fluctuations in the time series of the groundwater levels could lead to conclusions about possible irregularities in the shallow as well as the deep zones of the underground water. The concept was shown in this paper in the example of the hydroelectric power plant Mostar dam in Bosnia and Herzegovina. It should be noted that the defined methodology was a novel procedure for analyzing and determining the pathways of the flow of groundwater in the surrounding hydropower plant dams. In other words, such analysis could be conducted without the need for complex and expensive drilling and geophysical surveys, tracing, and all other methods.