The 16th Street Detention Basin discharges into a cutoff channel of the Mississippi River through twin 12-foot by 12-foot flood mitigation gates. During gravity flow the flood gates are open; conversely, during flood events, the flood gates are closed to prevent the Mississippi River from flooding the Bee Branch Watershed.
Today, when the flood mitigation gates are closed, all stormwater from the Bee Branch Watershed must be pumped through the floodwall/levee system into the Mississippi River. Under the new system, when the depth of floodwaters on the City side exceed the depth of the Mississippi River, stormwater will flow from the 16th Street Detention Basin into the Mississippi River automatically, eliminating the need to manually operate the system in inclement weather.
The project requires: ◦ Replacement of flood mitigation gates ◦ Repair of the concrete gate structure and the concrete wing walls ◦ Installation of check valves on the pump discharges ◦ Installation of new air release valves at the Mississippi River floodwall's Bee Branch pumping station