Planning context

The Lewes gauge’s historical rise is a measured record; future ranges are scenario projections, not certainties.

What has been observed

DNREC reports that sea level at the Lewes tide gauge has risen by about 15 inches since 1919. The trend has accelerated in recent decades. The state describes projections of roughly 1.2 to 1.5 feet of additional rise by 2050, with a wider range by 2100 depending on emissions and planning scenario. These are regional planning figures, not a forecast for the elevation change at a specific property.

Source note DNREC sea-level rise and flooding · 2025 Delaware Climate Action Plan

Flooding is not only a coastal issue

DNREC also identifies heavier rainfall, paved surfaces and aging drainage systems as factors in inland and urban flooding. Flooding can affect roads, stormwater and sewer systems, drinking-water infrastructure, power assets and emergency access. Saltwater intrusion and shoreline erosion create additional risks in coastal areas. The state notes that some properties outside mapped floodplains may still face risk because existing maps do not fully capture future sea-level rise or changing precipitation.

Source note DNREC climate and flooding overview

How to evaluate a property or community

Start with the FEMA Flood Map Service Center for the current mapped flood hazard, then review local drainage history, tidal flooding reports, elevation, access roads and the state’s resilience materials. Flood maps have defined uses and limitations; a property outside a mapped Special Flood Hazard Area is not a guarantee against flooding. For real-estate, insurance or engineering decisions, obtain a property-specific assessment from qualified professionals.

Adaptation options and trade-offs

Measures can include elevating or floodproofing structures, improving stormwater systems, restoring wetlands, using living shorelines where suitable, protecting critical facilities and planning future land use around changing conditions. No single measure works everywhere. Shoreline stabilization can shift erosion, drainage projects may move water downstream and hard infrastructure has maintenance costs. Evaluate alternatives at the watershed or community scale, not only parcel by parcel.

Where to find state planning material

The 2025 Delaware Climate Action Plan brings together the state’s planning goals and actions. DNREC’s flooding and sea-level rise page summarizes projections and resilience strategies. For an address-specific insurance determination, use FEMA’s official map service rather than a generalized state statistic.