Over the past 40 years, tidal flooding has quadrupled in many low-lying areas, but that change is accelerating due to sea level rising. According to a new study, even moderate rising could as much as triple coastal flooding events in many communities in the next 15 years. Based on even moderate projections for sea level rise from the 2014 National Climate Assessment, the Union of Concerned Scientists’ study “Encroaching Tides” calls attention to the threat of routine tidal flooding to much of the East and Gulf Coasts. As opposed to storm surges, tidal flooding occurs far more regularly, bringing water above the base sea level during routine tide patterns or, for example, twice a month due to the moon’s increased gravitational pull.

With anticipated sea level rise, even daily tides may flood many areas, according to the report. As the base sea level changes, deviations take on new meanings–which can have drastic implications for property.

Further, as sea levels continue to rise, tidal flooding events will become notably more extensive, with accompanying increases in disruptions and damage. As illustrated below, even minor flooding events will impact larger regions, and putting more property on the front line of regular flooding.

The duration of these events will also increase, potentially straining existing public infrastructure, demanding more emergency assistance, and leading to regular business interruption. Flood-prone areas in five of the 52 mid-Atlantic communities studied could be inundated more than 10% of the time, for example. In all of the communities studied, the number of tidal flooding incidents increased dramatically in projections for 2030 and 2045.