Verdantas Flow Labs partnered with AECOM to conduct physical hydraulic model studies for the proposed S-27 and S-29 Pump Stations—key elements of flood protection improvements along the C-7 and C-9 canals in Miami, Florida. Each station is designed to operate alongside a gated control structure, providing discharge capacity during storm surge and flood events and reducing flood risk for surrounding communities.

For both projects, physical models were constructed at a 1:14.6 scale to accurately replicate intake geometry and flow conditions. The studies aimed to identify and resolve any adverse hydraulic phenomena—such as excessive swirl, vortex formation, or non-uniform velocity distributions—that could impact pump performance or reliability.

S-27 Pump Station:
Baseline testing of the S-27 model showed that the original design met Hydraulic Institute (HI) criteria for swirl angles and did not exhibit unacceptable free surface vortex activity. However, intermittent Type II subsurface vortices were observed beneath the pipe gallery, particularly in pump bays 2 and 3 Design modifications included adding a 10° slope to the underside of the pipe gallery to eliminate air pockets during startup and installing baffle walls in each bay to eliminate the subsurface vortices. Documentation testing confirmed that the final design met all HI standards for swirl, vortex activity, and velocity distribution.

S-29 Pump Station:
The S-29 model initially exhibited unacceptable swirl angles and Type II subsurface vortices, especially in the pump bays closest to the control structure. To address these issues, a 10° sloped pipe gallery was added to allow trapped air to escape at start-up, and curtain walls were installed in each pump bay to disrupt vortex formation and improve flow patterns. These modifications successfully eliminated unacceptable subsurface vortices and reduced swirl angles to within HI criteria across all tested scenarios. The final design was validated through comprehensive testing, which confirmed compliance with all HI standards.

Both studies also evaluated alternate canal approach geometries and the effects of partial screen blockage. Results demonstrated that the recommended designs for both S-27 and S-29 are robust, maintaining reliable hydraulic performance across a range of operating conditions. The physical model studies provided valuable insights that guided targeted design improvements, ensuring both stations will operate efficiently and effectively during flood events. With final configurations featuring sloped pipe galleries and internal baffles or curtain walls, both pump stations meet industry standards and are well-positioned to support the region’s flood protection efforts.