Open-source system for reservoir water level monitoring using ultrasonic sensing

Accurate monitoring of reservoir water levels in urban and agricultural environments is essential but is often performed visually, a method that is both time-consuming and labor-intensive. This study describes the development and evaluation of a low-cost water level monitoring system based on the Internet of Things (IoT) concept. The system uses an ultrasonic sensor to continuously measure the distance to the water surface, incorporating automated data processing and real-time visualization through the ThingSpeak platform. Field tests were conducted in an open-air reservoir of 1,100 m³, and sensor readings were compared with manual observations from a limnimetric ruler, showing excellent agreement (R² > 0.999). Results obtained under uncontrolled environmental conditions confirm the feasibility of ultrasonic sensing for continuous monitoring of water levels in open reservoirs. The system is inexpensive (approximately US$ 150), easy to assemble, install, and maintain, and provides accurate measurements both day and night.

Keywords:
IoT; climatic changes; limnigraph; low-cost equipment