Riverfront Flood Wall and Promenade

The challenge

The river district flooded on average every four years, and each event closed the embankment road and soaked the ground floors of buildings more than a century old. Any defense had to fit in a narrow corridor between the road and the water without cutting residents off from the river.

The approach

I built a hydraulic model of the reach to set the design flood level with freeboard, then designed a reinforced concrete flood wall on piles with demountable gates at the river stairs. Two pumping stations handle rain that falls behind the wall while the river is high.

• Hydraulic model calibrated against three recorded floods
• Seepage and uplift checks under the wall foundation
• Promenade paving and seating built into the wall cap

The outcome

Since completion the wall has held back two floods that would previously have reached the buildings, and the promenade has become the busiest public space in the district.