p. 28

26.

[Sketches and calculations]

The maximum velocity or axis of a river when high is 0.35 of its depth below the surface; when low 0.15 of its depth. The curve of velocity at different depths is a parabola. Humphrey & Abbot

d=(0.317 + 0.06f)r

d,=Depth below surface of max, on velocity
f=force of wind (0 being calm 10 a hurricane &c)-if down + if upstream
r=mean radius (or area divided by the wetted perometer)

Example
If a canal 4 ft deep 40 ft wide on suface
[sketch]
26 feet on bottom, wind up stream with a
force of 3, required the depth of the axis of max. vel.

[calculations].