Esri High Water Map

Esri High Water Map

The High Water Map is a viewer application built with Javascript that leverages the Hydro Basemap and data services from NOAA and the National Weather Service to report current stream levels, and flood alert levels at more than 4,000 stream gauges across the United States.

The map was made for the general public interested in current flooding and forecasted floods, who want a quick and easy to understand view of the US.

The High Water Map displays gauge points that are currently flooding.

Each gauge on the map is symbolized according to the current respective flood level. Those flood categories are determined by NOAA, and they are as follows: normal (no flooding), near flood stage (action stage), minor flooding, moderate flooding, and major flooding. Animations are used to symbolize gauges that have Major Flooding forecasts to bring attention to those locations and to warn people of Major forecasted flooding.

Clicking on the stream gauge point will retrieve the current stream stage, and display it graphically on a bar chart that indicates the classification breaks for each flood level category for that particular gauge.

However, each gauge has its own unique classification breaks because rivers have inconsistent morphology. So, you can’t evaluate flood levels using a consistent numerical scale. Instead, you can apply a consistent qualitative classification scheme to all points, but the classification breaks will be different for nearly every stream gauge.

The application also provides a hydrograph for each gauge, which is displayed by clicking More. The graph shows water levels over time, and includes historic levels and forecasted levels.

Another addition to the map is the Flood Warning Areas, which are geographic representations of the National Weather Service Alert System. This system issues warnings to facilitate emergency information sharing for National Weather Service flood forecast zones for the emergency response and management community. When you click on one of the NWS polygons the current flood warning issued by the National Weather Service is displayed, along with a link to the NOAA- National Weather Service text alerts site. There you can find detailed information about the warning, including warning expiration dates.

To view the High Water Map please click here!