# A Real-Time Water Level and Discharge Monitoring Station: A Case Study of the Sakarya River
###### Abstract  
This study details the design and implementation of a real-time river monitoring station established on the Sakarya River, capable of instantaneously tracking water levels and flow rates. The system comprises an ultrasonic distance sensor, a GSM module (Global System for Mobile Communications), which enables real-time wireless data transmission to a server via cellular networks, a solar panel, a battery, and a microcontroller board. The river monitoring station operates by transmitting water level data collected by the ultrasonic distance sensor to a server via a communication module developed on a microcontroller board using an Arduino program, and then sharing these data through a web interface. The developed system performs regular and continuous water level readings without the need for human intervention. During the installation and calibration of the monitoring station, laboratory and field tests were conducted, and the obtained data were validated by comparison with data from the hydropower plant located upstream. This system, mounted on a bridge, measures water levels twice per minute and sends these data to the relevant server via the GSM module. During this process, precipitation data were utilized as a critical reference point for validating measurement data for the 2023 hydrological year, with changes in precipitation directly correlated with river water levels and calculated flow values, which were analyzed accordingly. The real-time river monitoring station allows for instantaneous monitoring of the river, achieving a measurement accuracy of within 0.1%. The discharge values recorded by the system showed a high correlation (\(\mathbf{r}^{2}=0.92\)) with data from the hydropower plant located upstream of the system, providing an accurate and comprehensive database for water resource management, natural disaster preparedness, and environmental sustainability. Additionally, the system incorporates early warning mechanisms that activate when critical water levels are reached, enabling rapid response to potential flood risks. By combining energy-independent operation with IoT (Internet Of Things)-based communication infrastructure, the developed system offers a sustainable solution for real-time environmental monitoring. The system demonstrates strong applicability in field conditions and contributes to advancing technologies in flood risk management and water resource monitoring. real-time monitoring station; Arduino; ultrasonic sensor; early warning system +
Footnote †: journal: Applied sciences  
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-flood risk [4]. In this context, the development of effective flood management systems is of paramount importance to mitigate the impacts of floods and minimize potential damages [1; 2; 3]. The integration of artificial intelligence and remote sensing technologies has become increasingly vital in enhancing flood prediction and management, allowing for early detection and more effective response strategies [5; 6; 7]. In recent years, advanced technologies used in flood warning systems, sensor networks, and real-time monitoring systems have made early detection of floods and rapid response to these events possible. These technologies play a crucial role in reducing flood risk by continuously and accurately monitoring water levels [8; 9; 10]. For instance, studies using ultrasonic distance sensors have demonstrated that these sensors can accurately measure river water levels, making them effective for early warning systems [11]. These systems offer significant advantages in water resource management, disaster preparedness, and environmental sustainability [12; 13; 14; 15; 16]. The integration of Internet of Things (IoT) technology has significantly enhanced the capabilities of these systems. IoT sensors can transmit data in real time to central systems, facilitating instant decision making and intervention [17; 18].