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<br />-:.."' o(-'} <br /> <br />OGl354 <br /> <br />CRDSS <br /> <br />MEMORANDUM <br /> <br />TO: <br />FROM: <br />DATE: <br />SUBJECT: <br /> <br />Ivan Walter <br />Ross Bethel <br />September 18, 1995 <br />Investigation into CROSS Use of Bear Report Crop Coefficients <br /> <br />State representatives have reviewed your memo report titled Analysis of the Bear Report Blaney-Criddle <br />Crop Coefficients and would like to ask for some clarification. <br /> <br />I. An early premise of your report is in the first sentence that "many irrigators do not irrigate after mid <br />to late July." Your report provides no support for this premise and based on our brief review of <br />Yampa basin diversion records, we do not believe this premise is correct. Your scope for this <br />investigation included the following statement: <br />"Our evaluation will include a review of the irrigation practices in Division 6 through <br />discussions with the Division Engineer and Water Commissioners." <br />We ask that you perform the review of irrigation practices stated in your scope and update your <br />memo to reflect that review. <br /> <br />2. The scope also states that you will "... contact the primary authors of the report...". We were <br />expecting statements in your memo indicating that "Mr. Hill believes that the coefficients are <br />appropriate for ...". The memo does not indicate that the authors were interviewed on the <br />appropriateness of the coefficients. We ask that you perform said interviews and report the results <br />in the memo. <br /> <br />3. It appears that in the memo consumptive use coefficients are made using a Hill methodology at <br />other weatehr stations in the Colorado River Basin for comparison with the Hill coefficients. This <br />seems like a circular argument. Isn't the bottom line how a derived consumptive use value <br />compares with measured Iysimeter data? When we run the Hili coefficients with CRDSS Gunnison <br />weather data, we obtain potential consumptive use about 50 percent greater than is caculated with <br />TR21 coefficients? Are not the bottom line consumptive use values more important than the <br />coefficients? Why not compare both TR21 and the Hill coefficients to Gunnison lysimeter data <br />to see which is more reasonable? As it presently stands we do not believe the conclusion of the <br />memo is supported by the memo since no practical comparisons are made. We ask that modify the <br />memo with some comparisons between consumptive use calculated with the Hill and TR21 <br />coefficients and measured consumptive use. <br /> <br />We believe the above requests are within the original scope of your investigation and, therefore, will not <br />be making more funds available for this subject. We believe the above requests are much more consistent <br />with your proposed scope and the issue at hand than the technical comparison of coefficients (rather than <br />practical results) that was performed in the memo. Please do not hesitate to call me if you have questions <br />or comments. <br /> <br />cc: Luis Garcia <br />George Fosha <br />Larry B razi I <br />