This case study focuses on the design and construction of rehabilitation works for an embankment dike discovered during a dam safety review conducted in 2015. The inspection revealed a topographic depression in a wooded area, which turned out to be closed by an undocumented dike built in 1926. Investigation campaigns highlighted several deficiencies: insufficient freeboard, lack of filters at potential seepage points, liquefaction risk, stability concerns, and inadequate surface protection. The site presented significant constraints: limited workspace, a fractured rock face at the right abutment, and a single access road shared with cyclists. The paper describes the options considered and the selected solution: constructing a new zoned dike downstream of the original dike, which was used as a cofferdam. Post-earthquake sensitivity analyses were performed using three residual strength estimates to demonstrate that the core and downstream filter would remain stable following the design seismic event. Foundation preparation was the most significant technical challenge. The unpredictable rock topography at the right abutment required concrete reshaping in stepped lifts oriented upstream to ensure proper contact with the core. The core consists of a blend of two materials whose granulometric variability required on-site pile homogenization prior to placement. The paper also presents non-conformities encountered during construction and the corrective measures implemented or accepted with justification. This project highlights the value of a flexible, integrated approach for the safe rehabilitation of hydraulic structures under complex site conditions.