Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
A contoured section is shown for depths up to 40 meters below land surface. Warmer colors (reds) indicate areas of relatively higher water content, and cooler colors (blues) indicate areas of relatively lower water content.
Public Domain.
