Of all the flume types, Trapezoidal Flumes follow the least standard conventions when it comes to the description of a flume's size.  

Trapezoidal Flumes are generally sized the width of the throat and the angle of the sidewall - although the latter is not strictly true for all Trapezoidal flumes as is evidenced by the Small and Large 60°-V flumes.  

Where a particular research organization has been involved, initials for that organization may be appended to the description (i.e. WSC - Washington State College).