Just Beach

Sandy beaches are being squeezed out of existence by erosion, coastal development, and sea level rise. This study provides a beach-scale cost analysis of managed retreat for Kauaʻi, estimating property acquisition, deconstruction, and infrastructure realignment costs across forty beaches through 2100. We find total adaptation costs of $3.1 billion (2025 USD), with half of that needed immediately. Infrastructure dominates costs at $2.0 billion, while residential and hotel development represent additional major cost drivers. Our results show how historical coastal planning decisions have created development lock-in that makes beach-centered adaptation costly, and provide information to support broader deliberations for sea level rise adaptation planning.

This study can be found here.