The Colorado River is the principal source of water for agriculture and riparian vegetation in Arizona, southern California, and southern Nevada. To account for water use by each State or individual and to verify lands fallowed for conservation programs and other water management needs, Reclamation routinely monitors more than 3.5 million acres of agriculture and riparian vegetation along the Lower Colorado River, from Hoover Dam south to the international border with Mexico. Multispectral satellite and aerial images are analyzed in combination with other spatial data in a Geographic Information Systems (GIS) environment to generate information regarding crop and riparian types, acreages, and water use estimates. Reclamation completed a significant update to the riparian vegetation database utilizing high-resolution multispectral National Agriculture Imagery Program (NAIP) imagery and an object-oriented based classification scheme resulting in revised vegetation types and crown closure.
These data and information assist Reclamation in meeting its U.S. Supreme Court mandate to provide detailed and accurate records of diversions, return flows, and consumptive use estimates of water diverted from the mainstream of the Lower Colorado River. This program is an example of implementing remote-sensing-based methodologies to routinely meet Reclamation’s water management needs.
http://www.usbr.gov/lc/region/g4000/wtracct.html
Reclamation uses remote sensing and GIS processes to map crop and riparian vegetation groups and to estimate the evapotranspiration associated with these groups. Examples of the Riparian database at Laguna Dam in Arizona and agricultural database near Coachella, California.