The Improving Crop Coefficients for the Middle Rio Grande Project (ICCMRG Project) was completed by the New Mexico Office of the State Engineer (NMOSE) under a grant from the United States Bureau of Reclamation. The objective of the ICCMRG Project is to assess actual crop water use for the years 2011 and 2013 through remote sensing technologies that estimate the evapotranspiration (ET) of individual crops within the Middle Rio Grande (MRG). The purpose of this assessment is to verify and/or improve crop coefficient (Kc) values being used in reference ET methods, modeling, and decision making tools. Current models rely on locally calibrated methods that are decades old, or on generic ET methods that must be calibrated on a gross level to determine actual water depletions. Using more accurate crop coefficient (Kc) values and producing actual ET estimates will improve water use data in the MRG, thereby reducing the need for separate empirical calibration in order to match historical stream flows. A reason for empirical calibration may be due in large part to a possible overestimation of crop ET in the Upper Rio Grande Water Operations Model (URGWOM) and the Upper Rio Grande Simulation Model (URGSiM). Current climate change projections, such as those used in the West-Wide Climate Risk Assessment programs, are trending towards more extreme instances of drought within the South Rockies LLC region. Therefore, accurately estimating agricultural water consumption under present conditions as well as through modeled future scenarios will help water resource managers project how much water might be available for allocation toward current ecological projects, as well as develop an understanding of what a more water-limited future will represent.
