Close up view of the mounting of a sampler tube in a stainless steel 0.4-foot HS Flume.  Unlike fiberglass construction where the tube is recessed in a sidewall cavity, the sampler tube has to be surface mounted on the flume sidewall.  

Also, where the intake port on a sampler tube in a fiberglass flume is recessed below the floor, here the intake has to sit above the flume floor.

Opposite the sample tube a high visibility staff gauge has been installed to aid the operator in taking a quick visual reading of the depth (and thus flow) in the flume.