Frequent Storm Surges Affect the Groundwater of Coastal Ecosystems

Recent studies have focused on the effect of large tropical cyclones (hurricanes) on the shore, neglecting the role of less intense but more frequent events. Here we analyze the effect of the offshore tropical storm Melissa on groundwater data collected along the North America Atlantic coast. Our meta‐analysis indicates that both groundwater level and specific conductivity significantly increased during Melissa, respectively reaching maximum values of 1.09 m and 25.2 mS/cm above pre‐storm levels. Time to recover to pre‐storm levels was 10 times greater for groundwater specific conductivity, with a median value of 20 days, while groundwater level had a median recovery time of 2 days. A frequency‐magnitude analysis indicates that the percent of time with salinization is higher for Melissa than for energetic hurricanes. Given the high frequency of these events (return period of 1–2 years), and the long time needed for groundwater conditions to return to normal levels, we conclude that increasingly frequent moderate storms will have a significant impact on the ecology of vegetated shorelines. Plain Language Summary Salinization and flooding events due to sea level rise and storm surges threaten coastal ecosystems, changing groundwater characteristics. Moderate and more frequent storm surges can have a significant impact on coastal ecology, similar to larger tropical cyclones. Salinity and water table elevation need time to recover to normal conditions. The recovery time is compared to the frequency of these moderate storm surge events to determine the effect on the coastal groundwater. Key Points Salinization Coastal areas Groundwater