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ASCE Standardized Penman Monteith calculation for several crops using the revised <br />coefficients and the differences were insignificant. Therefore, the original Wright <br />coefficients presented in ASCE Manual 70 were used. <br />• Daily Calibration Stations -The SPDSS Lower Plains calibrated coefficients were <br />originally developed using data from the CoAgMet Holyoke climate station. Peer review <br />participants questioned whether the Holyoke climate station is representative of an <br />irrigated area. Based on these comments and further investigation, the SPDSS Lower <br />Plains coefficients were updated using the NCWCD Sterling climate station data. <br />Coefficient Calibration Technique -Jon Altenhofen (NCWCD) suggested that rather <br />than developing regional calibrated crop coefficients, adjustment factors that could be <br />applied to the "non-crop" elements of the modified Blaney-Criddle equation should be <br />developed. This suggestion was considered and tested at the NCWCD Sterling climate <br />station. The procedure provided the same average monthly calibration results and similar <br />calibration results when applied over a period of multiple years. Further review and <br />discussion with other researchers indicated that the methodology we chose for SPDSS is <br />the more standard approach; therefore the SPDSS calibration methodology was not <br />revised. Another peer review participant suggested that rather than using the modified <br />Blaney-Criddle method, the Hargreaves method should be calibrated to the daily ASCE <br />Standardized method. Although we recognize this to be a valid approach, due to the <br />general acceptance and simplicity of the modified Blaney-Criddle method, SPDSS will <br />continue to use the approach documented in the memorandum for Task 59.1 -Develop <br />Locally Calibrated Blaney-Criddle Crop Coefficients. <br />Page 7 of 7 <br />