Comparison of various formulas for determining the Chezy coefficient

Conclusions

• 1. Equation (1) is presently the best substantiated by full-scale observations for R≤3 m.

• 2. The complexity of Eq. (2) for determining the variable exponent y necessitates resorting to specially calculated tables of CηR or to simpler equations.

• 3. For the range 0.3<R<5 m we can recommend also Eq. (5) which gives for this range deviations not exceeding ±(1–2)% of C by Eq. (1).

• 4. For 5<R<10 m we can recommend for determining C Eq. (6) or simpler Eq. (4), the results of calculating C by which coincide with Eq. (6).

• 5. Equation (1) with values of the exponent y determined from Eqs. (10) and (11) can also be used for calculating C.

• 6. The collection of full-scale data on the value of C for rivers and canals with values h_av>5 m is quite useful and expedient for a more complete substantiation of Eqs. (10) and (11) [4, 6].