Behavioural and contextual correlates of reported or committed uptake of Dry Flood-Proofing and Flood Barriers: Evidence from two distinct cross-sectional cohorts surveyed around the 2022 Eastern Australian floods

Riverine floods generate residential losses in Australia, yet many flood-prone households do not implement property-level mitigation measures. This study examines behavioural and contextual covariates associated with reported or committed uptake of Dry Flood-Proofing and Flood Barriers. Data came from cross-sectional cohorts surveyed before (n = 311) and after (n = 97) the early-2022 eastern Australian floods, collectively covering four states. Reported or committed uptake combined self-reported implementation with stated near-term commitment. Protection Motivation Theory guided behavioural variable organisation; pre-2022 coding and scaling rules were applied unchanged to the post-2022 cohort. Logistic models used 396 complete cases (311 pre-2022 and 85 post-2022), with inference clustered across 58 postcode-based area groups. Because both cohorts contributed to pooled estimation, wave-stratified diagnostics were apparent rather than external validation. Self-efficacy and response efficacy were consistently associated with both outcomes. Perceived implementation capability was prominent among the Dry Flood-Proofing point estimates, and perceived measure effectiveness among the Flood Barriers point estimates. Flood-risk communication was positively associated with both outcomes. Threat-appraisal point estimates differed by measure and survey context, whereas prior-flood-experience interactions were imprecise. The small post-2022 modelling sample and wave-specific estimation instability limited inference. In exploratory bounded-shift analyses, hypothetical 0.20 increases in perceived implementation capability for Dry Flood-Proofing and perceived measure effectiveness for Flood Barriers corresponded to mean model-implied probability differences of 0.083 and 0.078. These non-causal contrasts do not demonstrate intervention responsiveness or targeting efficiency. The findings support measure-specific analysis and identify practical information, implementation capability, and perceived effectiveness as candidates for prospective programme evaluation.