Xinyi Zhang Master’s Student Department of Ocean and Research Engineering University of Hawaii at Manoa **This defense will be held in person (POST 418) and over Zoom** Meeting ID: 859 1029 7666 Password: XinyiMS https://hawaii.zoom.us/j/85910297666 Coastal hydrodynamics in reef–lagoon–channel systems are controlled by complex interactions among wave transformation, breaking, and circulation. Although previous numerical studies have advanced process-based understanding, a systematic evaluation of XBeach for such systems remains limited. This study assesses the capability of XBeach to simulate hydrodynamics in an idealized reef system with a rip channel, using large-scale laboratory datasets under irregular wave conditions. The analysis evaluates the