Storms can increase beach resilience on a low-energy coast in the proximity of a harbor

Abstract

Storms drive energetic waves and induce high water levels on the nearshore. Hence, they are commonly associated with negative effects on the coast (i.e., beach erosion and coastal flooding). Beach resilience, the capability to resist and recover from storms, relies on the beach width and elevation. This study investigates the subaerial beach morphological response to storms on a micro-tidal, low-energy tropical beach located in the proximity of a harbor. The study area, situated on a barrier island on the northwestern coast of the Yucatan Peninsula, is prone to winter, tropical, and local storms. Beach surveys were carried out over the 2015–2023 period, with a high spatial and temporal resolution, along a 4-km stretch of coast, comprising beach transects located downstream (erosive beach) and upstream (accretive and stable beach) of the harbor jetties. Moreover, offshore wave conditions and water levels were measured to identify storm events. Pre- and post-storm beach surveys are employed to estimate beach geoindicators to assess the impact of 66 storms. Consistent with prior studies, field observations suggest that the beach response (accretive or erosive) is dependent on the water level and pre-storm beach morphology. Furthermore, a net subaerial sediment volume gain, correlated with seasonal changes on the dimensionless fall velocity parameter and water level, occurs during the winter storm season on the prograding/stable beach section. On the other hand, storms induced subaerial sand volume losses on the receding beach section exposed to the same forcing conditions. Thus, our observations suggest that moderate winter and tropical storms can contribute to increasing beach resilience in this region.