Abstract: Storm water pump stations are usually utilized to facilitate drainage of run-off water from segments of cities and neighborhoods. The velocity of inlet suction pipe (v) and the water depth from suction pipe onset to the water surface (submergence) represent important factors to avoid free and subsurface vortices at pump suction pipes. The present study set out to determine effect of submergence (s) and velocity of inlet suction pipe (v) on the hydraulic conditions of storm water pump station. Through this study, a physical model has been constructed to simulate a typical wet well side for multiple vertical suction pipes with the same diameter (d) and bell mouth out diameter (D). Many runs have been conducted through which effects of the pipe flow velocity, suction pipes spacing (b) and submergence were observed through the four glasses sided well model by means of naked eye, and detected by pressure gauge situated at suction side. Measurements were made for diameter and height of vortices formed. This study aims to determine the best arrangement of pumps intake suction pipes with respect to operational submergence to prevent the occurrence of any type of vortices using minimal wet well dimensions for a given flow rates. The results showed that, surface vortices do not formed when the submergence (s = 1.75D) and spacing (b > 2D) for Fr (u) = 1.

Keywords: Vortices, Pump Intake, Submergence.