Drifting Depth Sensor – ADS

28. Drifting Depth Sensor

Most flow monitoring data can be described by the Manning Equation using either the Design Method, the Lanfear-Coll Method, or the Stevens-Schutzbach Method.  Data that do not lie on a pipe curve generated by one of these methods indicate that either the hydraulics are different or that the flow monitor is not working correctly.  This scattergraph displays data from a flow monitor with a drifting pressure depth sensor.  Note that the reported flow depth drifts over a wide range without a corresponding change in velocity.  In this case, as series of pipe curves are observed at multiple depths and deviate significantly above and below the manual confirmations.  The data from this flow monitor are invalid and should be disregarded.