Virginia Coastal Resilience Master Plan (CRMP) Graduated Coastal Flood Extents for the Far Future High planning scenario.

Coastal flooding occurs when tidal waters exceed the typical shoreline and inundate upland areas, including both tidal inundation and storm surge. This dataset depicts the extent of potential coastal flooding under various flood conditions. 10-foot resolution raster data is classified and colored to represent the extent of the most frequent (least-rare) floods that may impact a given area. The included flood conditions range from daily high tides to rare storm surge events, with probabilities derived from statistical analysis of historic events. The storm surge events are described in terms of their relative annual exceedance probability (AEP), which represents the percentage chance that a given flood magnitude will occur in a given year. The specific flood conditions included are: Mean Low Water, Mean High Water, 50% AEP, 20% AEP, 10% AEP, 4% AEP, 2% AEP, 1% AEP, and 0.2% AEP.

In the CRMP, planning scenarios are defined by their time horizon and projection range, representing future conditions and the uncertainty inherent in climate forecasts that project them. This dataset contains information for the Far Future time horizon, meaning it is suitable for planning through the next 75 years and is based on climate data most relevant to the period between 2060 and 2100. Within this time horizon, this dataset shows a High climate change projection, indicating a less likely but possible future with higher sea level rise and precipitation estimates, which may be favored for use in decisions with little tolerance for risk.

The CRMP’s coastal flood modeling considered changing relative sea level rise projections based on the NOAA 2017 Intermediate High Curve. Complete documentation of the source data and production process can be found in the VA CRMP Phase I Appendix C – Coastal Flood Hazard Framework Report (Dewberry, 2022).

Related resources include the VA CRMP Master Plan and reports (https://www.dcr.virginia.gov/crmp/) and Coastal Resilience Web Explorer (https://www.dcr.virginia.gov/crmp/cr-web-explorer).

For questions or additional information, please contact Flood.Resilience@dcr.virginia.gov.