Current　scouring　effects　and　additives　increase　the　risk　of　failure　in　underwater　structures,　and　poor　observation　complicates　the　identification　and　assessment　of　damage.　We　present　a　novel　index　for　assessing　non-dispersible　underwater　concrete　columns　using　stress-wave　and　impedance.　A　piezoelectric　lead　zirconate　titanate　sensor　was　used　to　monitor　the　compression　process　of　non-dispersible　underwater　concrete　columns　and　ascertain　the　extent　of　damage.　The　proposed　index　divides　the　damage　process　into　initial　compaction,　elastic　deformation,　and　crack　development　and　failure　stages.　Additionally,　the　proposed　method　quantifies　and　identifies　damage,　producing　results　that　agree　with　those　for　the　axial　compression　failure　characteristics.　©　Springer-Verlag　GmbH　Germany,　part　of　Springer　Nature　2024.