H Series of Flumes consists of three classes of flumes (HS, H, and HL) which conform to the same general design (a uniformly converging section, rectangular in cross-section, and a flat floor).  The throat is formed by sloping the tops of the sidewalls downwards in the direction of flow.

While similar, the geometries of each class of H Flume do vary, with the width and length increasing from the HS [the narrowest and longest (relative to width)] through the H and to the HL [the widest and shortest (relative to width)].

Where D is the depth of the flume:

HS Flumes have:

• Width = 1.05D
• Length = 1.5D
• Throat Width = 0.05D

H Flumes have:

• Width = 1.9D
• Length = 1.35D
• Throat Width = 0.1D

HL Flumes have:

• Width = 3.2D
• Length = 1.5D
• Throat Width = 0.2D

HS Flumes are for small flows, H Flumes for average to large flows, and HL Flumes for large flows.