Flood Risk and Avoidance
Protecting our infrastructure from flooding
State agencies are responsible for building and maintaining infrastructure that keeps the state running. Roads, schools, wastewater treatment and parks are planned and paid for with state tax dollars. They also have long lifespans. A bridge built today will be expected to still be functional more than sixty years from now.
Changes in sea levels, temperatures, and rainfall as a result of climate change mean that infrastructure like schools and roadways will experience conditions over their lifespans that are very different from the conditions in which they were built.
Building with future conditions in mind prevents the need for expensive repairs or replacements. Building to a higher standard at the beginning can save taxpayer dollars in the long run.
State agencies are required to prioritize resilency and flood risk when building new infrastructure and retrofitting or updating existing structures. Under Governor Markell's Executive Order 41, state agencies are required to avoid building within areas that are currently or will be at high risk of flooding, especially with concern to the higher risks posed by sea level rise and climate change. New and existing structures must be constructed with future conditions in mind, with measures to reduce their vulnerability to flood hazards.
In order to help agencies meet this requirement, the Flood Avoidance Workgroup was formed. The workgroup developed resources to help agencies identify flood risk areas and to provide technical information on building adaptable, sustainable infrastructure.
Flood Avoidance Resources for Delaware State Agencies
Guide Document for Avoiding and Minimizing Flood Risk
Avoiding and Minimizing Risk of Flood Damage to State Assets: A Guide for Delaware State Agencies provides state agencies with guidance and step-by-step instructions for avoiding and minimizing flood risk to state assets.
This easy-to-use guide will help state agencies evaluate and avoid both existing flood risk and future risks posed by climate change during the planning and design of public building and infrastructure projects. The guide was developed for state agencies specifically, but local governments, businesses and individuals are welcome to use it to better understand and prepare for flood risks today and in the future.
- Full Document: Avoiding and Minimizing Risk of Flood Damage to State Assets: A Guide for Delaware State Agencies
Flood Risk Adaptation Map
The Flood Risk Adaptation Map is a planning tool that depicts the land area that would be flooded during a 1 percent annual chance flood if mean sea levels in the state rise by three feet. It allows users to visualize storm impacts at late century with moderate levels of sea level rise, and mid-century should sea levels rise at a more rapid rate.
This map was designed to be used alongside the Delaware Sea Level Rise Inundation Map (de.gov/slrmap) and the Federal Emergency Management Agency's Flood Insurance Rate Map. Planners should consult all three maps in addition to comprehensive surveying to fully assess the flood risk of a site.
The map does not depict the increased risks associated with changes in coastal landforms, increased wave heights or other secondary hazards that may occur as sea levels rise. Prior to using the map, users should review Delaware Flood Risk Adaptation Maps: Methods, Assumptions and Limitations.
This brief document provides an overview of the map, nomenclature and assumptions that were made while producing the map: Flood Risk Adaptation Map fact sheet
Access the Flood Risk Adaptation Map*
The Flood Risk Adaptation Map GIS files can be downloaded on Delaware’s First Map system.
To use the data in GIS applications
- 1. Visit https://firstmap.delaware.gov
- 2. Navigate to the Data section
- 3. Choose the “State Services” tab
- 4. Select “Environmental Data.”
Alternatively, users can navigate to the site directly: https://firstmap.delaware.gov/arcgis/rest/services/Environmental/DE_FloodRiskAdaptationMap/MapServer.
* The Flood Risk Adaptation Map is not yet available as a web viewer. Please check back for updates. For more information about the Flood Risk Adaptation Map, please contact the DNREC Division of Watershed Stewardship at (302) 739-9921 or the DNREC Division of Energy and Climate at (302) 735-3480.