An interior view of a domed top metering manhole with a Parshall flume in it.  The flume was provided with an ultrasonic sensor mounting bracket and the customer has a probe holder in the inlet end adapter.  

Note the standing water on either side of the flume.  Metering manholes should be either equiped with integral fiberglass benching or a concrete shoulder should be poured between the flume and the manhole wall.