Map Explainers guides.
Wetlands Mapper identifies wetland and habitat information, while FEMA mapping depicts adopted flood hazards. Compare each layer for its own purpose instead of treating their boundaries as equivalents.
Web Soil Survey hydrologic groups describe runoff and infiltration characteristics for mapped soil units. Use the selected area and component data as context, never as a standalone flood-zone ruling.
In StreamStats, verify the basin outlet and delineated drainage area before generating flood-frequency estimates. Modelled peak flows require method, region, and limitation context; they are not observed water levels.
After a documented flood, use the USGS event and point identifiers to retrieve relevant high-water marks and their measurement details. Do not attribute one mark to another site.
The Coastal Flood Exposure Mapper compares community assets, population, and natural protection across selected layers. Its output supports planning questions, not a parcel certificate.
NOAA’s Sea Level Rise Viewer displays coastal inundation scenarios for selected water levels. Treat them as planning context rather than FEMA zones, present conditions, or forecasts.
Use the National Inventory of Dams map to identify nearby entries and open the official record for the matching dam. Distance on the viewer does not establish an inundation path or downstream safety.
Find the correct levee system in the USACE database, then note its identifier, inspection information, and displayed risk details. Proximity to a levee does not promise protection for an address.
A FEMA coastal risk score summarizes community-scale indicators, not the effective zone for one structure. Keep the rating geography, percentile, and expected-loss context attached.
Read the National Risk Index riverine rating, percentile, and expected annual loss at its county or tract scale. Those community indicators are not interchangeable with a property’s FIRM zone.