Patent ID: 8924167

Claim:
A system for monitoring the level of sediment accumulated on a bottom of a settling chamber of a stormwater management facility, comprising: an elongated capacitive sensor extending into the sediment and into a fluid layer above the sediment, wherein the capacitive sensor periodically makes multiple measurements of the electrical capacitance of the sediment and of the fluid layer at multiple elevations above the bottom of the settling chamber and generates multiple corresponding capacitance readings, each of which has a corresponding capacitance elevation level; a sensor microprocessor in electrical or wireless communication with the capacitive sensor, wherein the sensor microprocessor acquires the capacitance readings and determines a maximum capacitance from among the capacitance readings, and wherein the sensor microprocessor compares the maximum capacitance with a liquid reference capacitance that is indicative of the presence of a liquid layer above the sediment; an ultrasonic sensor located above the sediment and in electrical or wireless communication with the sensor microprocessor, wherein the ultrasonic sensor is activated by the sensor microprocessor when the maximum capacitance is less than the liquid reference capacitance, and wherein the ultrasonic sensor, when activated, propagates an ultrasonic transmission signal downward toward the sediment and receives an echo signal reflected from the sediment, and wherein the ultrasonic sensor measures an echo delay between the time of propagation of the transmission signal and the time of reception of the echo signal and transmits the echo delay in digital data format to the sensor microprocessor, which uses the echo delay data to calculate a sediment level relative to the bottom of the settling chamber; and a wireless transmission unit located above the sediment and in electrical or wireless communication with the sensor microprocessor, wherein the wireless transmission unit acquires the sediment level in digital data format from the sensor microprocessor and wirelessly transmits the digital sediment level data to a remote computer, which compiles the digital sediment level data in a database.