A Hydrological and Hydrochemical Study of the Gudiyalchay River: Understanding Groundwater–River Interactions

The Gudiyalchay River plays a crucial role in the environment and human activities of the Guba area in north-eastern Azerbaijan, supporting agriculture and the local water supply. Despite its significance, the river has received little scientific attention. The groundwater beneath the Gudiyalchay riverbeds, a vital source of drinking water and the second primary source of river recharge after snowmelt, remains insufficiently studied, with most monitoring data being outdated. With climate change intensifying, such research is critical to mitigating potential water risks. In this work, all available geological, hydrogeological, climatic, and hydrochemical data were collected to characterize the study area and analyze the seasonal fluctuations in river flow and total dissolved solid (TDS) values, with a focus on the interactions between the river and groundwater at the Khinaliq, Giriz, and Kupchal flow stations. The analysis shows that both river and groundwater TDS values are within acceptable drinking water limits, but continuous data collection is important to confirm this. Flow rate analysis and a literature review revealed that variations in flow rate are linked to seasonal changes, with the flow rate near the Giriz station indicating potential groundwater influence. Based on the literature review and analysis, a simplified hydrogeological diagram is created to provide a clearer understanding of the interactions between the river and groundwater systems.