Surging Seas Sea level rise analysis by Climate Central

Delaware and the Surging Sea

Description: A vulnerability assessment with projections for sea level rise and coastal flood risk.
Date: September 2014

Full PDF of Report

Executive Summary

Under a low-range sea level rise scenario, Delaware is likely to see record-breaking coastal floods within the next 20 years, and near certain to see floods more than 5 feet above the high tide line by 2100. Under a rapid rise scenario, the state is near certain to see floods above 9 feet by end of century.

62,000 acres of land lie less than 5 feet above the high tide line in Delaware. Some $1.1 billion in property value, and 20,000 homes, sit on this area. These figures jump to more than $2 billion and nearly 40,000 homes on 104,000 acres of land under 9 feet.

More than 19,000 people are residents in the homes below 5 feet, and more than 41,000 are residents below 9 feet. Greater than half of each group are in high social vulnerability areas – more than two-and-a-half times the expected proportion based on statewide vulnerability patterns – meaning that those with the least ability to cope with coastal flooding will be disproportionately exposed to it.

The state has 428 miles of road below 5 feet; 9 houses of worship; 2 power plants; and 87 EPA-listed sites, such as hazardous waste dumps and sewage plants. At 9 feet, these numbers grow to 782 miles of road; 36 houses of worship; 4 power plants; and 135 EPA-listed sites.

Sea levels are rising at an accelerating rate, and the scientific community is confident that global warming is the most important cause. Higher sea levels translate to more and higher coastal floods. To forecast future risk, this analysis integrates historic local sea level trends and flood statistics with global sea level rise scenarios, developed by a multi-agency federal task force led by NOAA in support of the recent U.S. National Climate Assessment.

This report is being released as a high-level summary of findings and methods, coincident with the online launch of a Surging Seas Risk Finder tool for the state, providing much more detailed and localized findings, and accessible via

The tool includes: 

  • Interactive local projections of sea level rise and increasing coastal flood risk from 1-10 feet by decade;
  • A zooming, zip-searchable map of low-lying areas threatened, plus layers showing social vulnerability, population density and property value;
  • Detailed assessments of populations, property, infrastructure and contamination sources exposed, for each implicated county, city, town, zip code, planning district, legislative district and more;
  • State- and county-wide heat maps facilitating high-level vulnerability comparisons; and
  • Brief customized “fast look” reports that integrate key findings from across all analyses for each locality, and provide interpretation and context.

Detailed knowledge of vulnerability is a critical tool for communities seeking to build resiliency to the climate challenges of today and the future.