The BOR administers the Operating Criteria and Procedures (OCAP) to determine irrigation status for the Newlands Reclamation Project, which covers approximately 61,000 acres in Nevada. The OCAP directs BOR and the Truckee-Carson Irrigation District to identify and report "the number of acres of eligible land irrigated in the Project" as well as "possible irrigation of ineligible land" and "eligible land that was not irrigated." Using spaceborne SPOT (Satellite Pour l’Observation de la Terre) 20-m imagery, BOR derives an average vegetation index for each of 8,000 agricultural fields four times per year to assist in the determination of irrigation status. This program is an example of implementing remote-sensing-based methodologies to routinely meet BOR water management needs.
http://www.usbr.gov/projects/Project.jsp?proj_Name=Newlands%20Project
Agricultural fields shown with final annual irrigation status determination based on four SPOT satellite time frames.