Often used in hydraulic when monitoring speed; flow rate
Drawing labels, details, and other text information extracted from the CAD file (Translated from Spanish):
elevation, viewnumber, sheetnumber, progressives and coordinates box, income channel section, energy dissipator, prog. start, starting point, baffle, transition, surface of land, surface of land, channel, double mesh, details – energy dissipating structure, section d-d ‘, section e-e’