§ 155.031 MANNING’S EQUATION.

   The hydraulic capacity of storm sewers shall be determined using Manning’s equation:

      V = 1.486 R2/3 S½
         n

   (A)   The variables of this equation are: V=Mean velocity of flow in feet per second; R=the hydraulic radius in feet; S=the slope of the energy grade line in feet per foot; and n=roughness coefficient.

   (B)   The hydraulic radius, R, is defined as the cross-sectional area of flow divided by the wetted flow surface or wetted perimeter. Typical n-values and maximum permissible velocities for storm sewer materials are listed in Appendix A, Table 4. Roughness coefficient n-values for other sewer materials can be found in standard hydraulics texts and references.

(Ord. 1995-10 § X A, passed 10-13-1995)