SmartCover features the SubSonic Dual Sensor, combining the accuracy of ultrasonic with the expanse of a pressure sensor, giving full dynamic range of manholes from the bottom of the channel to the cover. Water level patterns are detected from the outset and continue beyond when the ultrasonic sensor becomes submerged. The sealed submersion sensor is virtually maintenance-free, issuing notifications when overflow levels detected. No confined space entry. Satellite-based communications makes it impervious to cell or power outages.