A precision water-level and sediment-load monitoring system—an update

This paper presents an update of the basic design and performance of a precision pneumatic water-level gage that is suitable for application in most severe environments. The key to the success of this pneumatic bubbler gage is the incorporation of an analog “traveling-wave” low-pass filter which pre-filters out the noises generated by wind waves, swells and other short-period disturbances. It eliminates the high cost and error problems associated with a stilling well. The system satisfies the basic design requirement of ± 1mm resolution of water head. With multiple gages setup, the system can also be used to monitor the sediment load in rivers, estuaries and coastal waters.