I am modeling a river stream using Ansys-Fluent. I am using k-epsilon turbulence model. My question is, can the turbulence parameters like "k", "epsilon" or "turbulent intensity" be estimated using any empirical formulas? There are some empirical formulas as below for pipe flows. Can these formulas also be used for open channels?

Turbulent Intensity (pipes)~= 0.16*Redh(-1/8)

epsilon(pipes)~=C 0.75 k 1.5/L