The Water level overflow detector employs a simple mechanism to detect and indicate if the water is about to escape from the canal/river boundary walls. It is a contact-based sensor mounted amidst the river/canal on a pole. The pole is secured to the ground via a cement foundation. The sensing is done by using a set of probes which are placed at different levels in increasing order of height; common probe (i.e. a supply carrying probe) is placed at the base. The highest level represents the high/critical condition while the base level represents the minor or normal condition.
When the water-level is below the minimum detectable level the sensor indicates that the canal is nearly dry. As the water reaches minimum level the connection between the probes is completed (through the conducting medium – water) and the switch is closed. This causes the switch to transit from “off to on” state, which in turn generates an electric signal. This signal is detected and processed by the RTU which triggers an alarm. The same procedure is applied to all other water levels. This sensor is capable of reporting extreme water levels whether high or low.