The unique shape of the H Flume allows it to measure a wide range of flows.  As a result, a common application of the flume is stream gauging - where flows can run from a trickle to a torrent.

Below is a great time lapse video showcasing the H flume's ability to handle a wide range of flow conditions.  The video covers a six day period captured in 30 minute intervals and details the dramatic increase in flows due to a significant precipitation event.

From low flows to high flows and back again, the H flume never misses a beat.  

Source:  YouTube