Sea level rise drives increased tidal flooding frequency at tide gauges along the U.S. East and Gulf Coasts: Projections for 2030 and 2045.

Kristina A. Dahl,Erika Spanger-Siegfried,Melanie F. Fitzpatrick,Guy J-P. Schumann

doi:10.1371/journal.pone.0170949

Abstract

Tidal flooding is among the most tangible present-day effects of global sea level rise. Here, we utilize a set of NOAA tide gauges along the U.S. East and Gulf Coasts to evaluate the potential impact of future sea level rise on the frequency and severity of tidal flooding. Using the 2001–2015 time period as a baseline, we first determine how often tidal flooding currently occurs. Using localized sea level rise projections based on the Intermediate-Low, Intermediate-High, and Highest projections from the U.S. National Climate Assessment, we then determine the frequency and extent of such flooding at these locations for two near-term time horizons: 2030 and 2045. We show that increases in tidal flooding will be substantial and nearly universal at the 52 locations included in our analysis. Long before areas are permanently inundated, the steady creep of sea level rise will force many communities to grapple with chronic high tide flooding in the next 15 to 30 years.

Highlights

Sea level rise has the potential to inundate significant stretches of the U.S coastline by the end of this century [1]
To confirm that exceedances of the flooding threshold are consistently associated with the issuance of Coastal Flood Advisory (CFA), we examined each flood event identified by the Inundation Analysis (IA) method for each tide gauge for the two-year period 2012–2013 and determined whether it was correlated to a specific CFA or other National Weather Service-issued message related to coastal flooding
For 52 of the 59 tide gauges analyzed, two-thirds or more of the flood events identified by the IA were associated with CFAs or other flood statement

Summary

Introduction

Sea level rise has the potential to inundate significant stretches of the U.S coastline by the end of this century [1]. Local flooding thresholds can be reached more during average high tides. In the absence of coastal adaptation measures to protect against rising seas, some coastal areas could fall below the high tide line by the end of the century. Global sea level rose by an average of 1.2–1.7 mm per year over the course of the 20th century [2,3]. From 1993 to 2010, the global rate has accelerated to 3.0 +/- 0.7 mm per year [2,3,4,5] This acceleration is attributed mainly to ocean warming, a quickening pace of land ice loss, and a net transfer of groundwater from the land into the sea [6,7,8,9]

Methods

Results

Conclusion