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.
Sand covers a significant portion of the Earth’s surface, including the Grand Falls area of Coconino County, AZ. The vadose zone (unsaturated zone) in a soil is of particular interest because it...
data.gov
An official website of the GSA's Technology Transformation Services