Land subsidence contribution to coastal flooding hazard in southeast Florida

Abstract. Over the past decade, several coastal communities in southeast Florida have experienced a significant increase in flooding frequency, which has caused significant disturbance to property, commerce, and overall quality of life. The increased flooding frequency reflects the contribution of global, regional, and local processes that affect elevation difference between coastal communities and rising sea level. In a recent project, funded by the state of Florida, we monitor coastal subsidence in southeast Florida using GPS and InSAR observations, in order to evaluate the contribution of local subsidence to the increased coastal flooding hazard. Preliminary results reveal that subsidence occurs in localized patches (< 0.02 km2) with magnitude of up to 3 mm yr−1, in urban areas built on reclaimed marshland. These results suggest that contribution of local land subsidence affect only small areas along the southeast Florida coast, but in those areas coastal flooding hazard is significantly higher compared to non-subsiding areas.