South Florida Water Management District (SFWMD) contracted northwest hydraulic consultants (nhc) to conduct physical hydraulic model studies of two outflow pumping stations in the Everglades. Two separate Froude-scaled, geometrically similar, undistorted three-dimensional model studies were conducted at approximate scales of 1:16. Each model included 500 feet of the redirected canals upstream of the stations, the pump station sump, and the pump suction piping up to the impeller of each pump. Testing the existing design of both stations with the new intake canal layout identified several performance problems and determined the cause of the documented vibration and erosion of the concrete floor in the pump bays. Pump intake modifications were developed using models to correct the performance deficiencies. These cost effective and innovative solutions included the use of the stop logs to control the formation of surface vortices, converging sidewalls and false back walls with center splitters and pump inlet vanes to reduce flow pre-swirl entering the pumps and eliminate subsurface vortex formation. Prototype pump performance testing with the modified pump bays confirmed that the modifications improved pump intake flow hydraulics with flow capacity and head meeting or exceeding previous pump operation and vibration was within acceptance levels.
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