Samani, Zohrab, authorBawazir, A. Salim, authorBleiweiss, Max, authorSkaggs, Rhonda, authorU.S. Committee on Irrigation and Drainage, publisher2020-06-172020-06-172007-10https://hdl.handle.net/10217/208254Presented at the Role of irrigation and drainage in a sustainable future: USCID fourth international conference on irrigation and drainage on October 3-6, 2007 in Sacramento, California.Pecan is a major crop in Lower Rio Grande Basin. Currently there exist about 30,000 acres (12,000 ha) of pecan orchards at various stages of growth which consumes about 40 percent of irrigation water in the area. Crop evapotranspiration (ET) varies with age, soil type and method of management. The ET variation and lack of information on optimum crop ET result in significant variation in productivity and income. In order to maximize the returns from limited water resources, there is a need for a better understanding of pecan optimum ET. ET was measured using three eddy covariance flux towers, which were installed in selected fields in the irrigated area. This paper describes a process where remotely sensed data from ASTER were combined with ground level information to estimate pecan ET and crop coefficient (Kc) throughout the area. The measured cumulative annual pecan ET were determined as 1470 mm (4.82 ft) compared to a predicted value of 1415 mm (4.68 ft) using the remote sensing model. Regression summary for measured ET as depended variable resulted in Standard Error of Estimate (SEE) of 0.86 mm/day and adjusted R2 of 0.9045 for 363 days of measured data.born digitalproceedings (reports)engCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.Text