The Comparison of Velocity Formulas Used in Stormwater and Sewage DesignThe diameter and the slope of the pipe for the desired discharge value are calculated in stormwater / sewage systems design by using different velocity formulas. In Turkey, governmental offices that prepare contracts for stormwater and sewage collection systems prefer and use different velocity formulas. In this study, the effects of using such formulas on system characteristics are investigated in an attempt to provide guidance for system designers.