Underside detail of a 2-inch 45 Degree SRCRC Trapezoidal Flume for the University of Arizona.  

The detail shows how the stilling well is attached to the flume.  The geometry of the Trapezoidal Flume is such that the stilling well is essentially a detached style that is then connected and molded to the flume. This is somewhat different than the way that stilling wells are attached to vertically walled flumes (like the Parshall, H style, and Cutthroat Flumes).