Virginia Coastal Resilience Master Plan (CRMP) Combined Flood Hazard Flood Presence for 1% Annual Exceedance Probability (AEP) event in the Far Future Moderate planning scenario.

This dataset depicts the geographic area likely to be inundated by a major (1% AEP) flood event resulting from any of the three independent flood sources: coastal, rainfall-driven, and riverine. Areas within this 1% AEP extent have a 1-in-100 chance, or greater, of experiencing flooding in any given year, based on statistical analysis and modeling of historical events. Data is classified and colored to represent the flood type present with a 1% AEP for each 10-foot cell in the CRMP study area, meaning that if a site is subject to multiple different types of flooding, a unique classification for the combination of flood types impacting the area is shown (e.g., coastal and rainfall-driven flooding).

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 Moderate climate change projection, indicating a “best estimate” for future conditions, suitable for decisions where a higher level of risk is acceptable.

This combined flood hazard information draws leverages data from multiple sources, including CRMP 2022 coastal flood modeling, 2024 rainfall-driven flood modeling, and riverine flood data from the Federal Emergency Management Agency (FEMA). Complete documentation of the source data and production process for coastal flooding can be found in the VA CRMP Phase I Appendix C – Coastal Flood Hazard Framework Report (Dewberry, 2022). For rainfall-driven flooding, the documentation is provided in the Pluvial Modeling Final Report (Dewberry, 2024, Addendum A).

Related resources include the VA CRMP Master Plan report (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.