Development of a GSM-Based Automated Water Level Monitoring System for the River Benue Flood Plain

Seasonal flooding along the River Benue corridor in Benue State, North Central Nigeria, causes significant loss of life and property annually, and early warning systems are critically lacking at the community level. This project developed a GSM-based automated water level monitoring system designed for deployment at strategic points along the River Benue flood plain. An ultrasonic ranging sensor (HC-SR04) interfaced with an Arduino Uno microcontroller was used to measure water surface distance from a fixed reference point. The system transmits alert SMS messages to registered emergency contacts when water levels exceed three pre-defined threshold levels corresponding to watch, warning, and danger classifications. A SIM800L GSM module was integrated for real-time transmission, and data were logged to an SD card for post-event analysis. The prototype was bench-tested using a calibrated water tank at six different water level conditions. Measurement accuracy was within plus or minus 2.1 centimetres across the 0 to 300 centimetre measurement range. SMS delivery time averaged 8.3 seconds from threshold crossing to message receipt in network-available conditions. The system operated continuously for 72 hours on a 7.4Ah lithium polymer battery, with a projected solar-extension runtime of indefinite duration. False alarm rate during testing was 2.8 percent, attributed to surface turbulence. The study recommends integrating rainfall sensor data as a predictive input and deploying multiple units in a networked array to provide wider flood plain coverage across Benue and Kogi States.

Keywords: water level monitoring, GSM alert system, flood warning, River Benue, microcontroller