The SWRC operates the Walnut Gulch Experimental Watershed in southeastern Arizona as an outdoor laboratory for studying semiarid rangeland hydrologic, ecosystem, climate, and erosion processes.

An overview of SWRC and WGEW research is provided in a downloadable brochure:   SWRC Brochure 

   WGEW Instrumentation Map     Santa Rita Instrumentation Map


Long-Term Remote Sensing Database, Walnut Gulch Experimental Watershed, Arizona, USA

M.S. Moran1, C.D. Holifield Collins1, D.C. Goodrich1, J. Qi2,

D.T. Shannon3 and A. Olsson4

1 USDA ARS Southwest Watershed Research Center, Tucson, AZ

2 Michigan State University, Center for Global Change and Earth Observations and
Department of Geography, East Lansing, MI

3 Wu-Wei Software, Tucson, AZ

4 Office of Arid Lands Studies, Arizona Remote Sensing Center, Tucson, AZ

Abstract.   The USDA Agricultural Research Service, Southwest Watershed Research Center, Walnut Gulch Experimental Watershed (WGEW) is a located in the San Pedro Valley of Southeastern Arizona.  The long-term, high-quality data collection conducted over decades at WGEW has encouraged numerous hydrologic remote sensing (RS) experiments funded by National Aeronautics and Space Administration (NASA), National Oceanic and Atmospheric Administration (NOAA) and National Science Foundation (NSF).  This continuing work has resulted in an accumulation of hundreds of spectral image files from a variety of satellite- and aircraft-based sensors (the “images”) and the association of those images with data files containing high-quality ground-based measurements of soil, plant and atmospheric conditions (the “ground data”).  These images and the supporting ground data have been compiled in one location and archived in an orderly fashion to enable easy queries of either image or supporting ground data files.  Metadata on all archived images and ground data were entered into a database in 2006, named the WGEW Image and Ground Data Archive or WIDGA06.  The database WIGDA06 can be downloaded using the link below and it provides contact information for obtaining copies of the image and data files.  Many images are available in the University of Arizona, Arizona Regional Image Archive (ARIA) at

To download the WIGDA06 Database, click HERE.
IMPORTANT:  Be sure to read this README file first.

Other Remote Sensing Data:

ARIA is an interdisciplinary resource system and online clearinghouse for digital image and map data for the Sonoran Desert region, including the U.S. Southwest and northern Mexico ( 

The SRER Digital Database (SRER DD) is an online accessible collection of geographically explicit long-term vegetation and precipitation measurements, and repeat photography images spanning over 100 years (