This darter's habitat is highly specialized and dependent on water quality and stream velocity.
The severity of hydraulic action increases with stream velocity and current stream load.
The Hjulström curve shows that sand particles of a size around 0.1 mm require the lowest stream velocity to erode.
High stream velocities, however, may dislodge R. boylii egg masses from oviposition substrates.
Saugers are usually found in areas with high turbidity, low channel slope, low stream velocity, and deep water.
This downwash alters the free stream velocity, by rotating it downward, towards the downwash.
The index is a measure also of stream velocity and sediment load, those quantities being maximized at an index of 1 (straight).
A shroud of suitable geometry can increase the flow velocity across the turbine by 3 to 4 times the open or free stream velocity.
The students calculate stream velocity.
This causes the air passing through the rotor plane to have a smaller velocity than the free stream velocity.