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. . PARSONS ) Memorandum To Larry Lang January 18, 2002 Page 2 ~ The storm distributions incorporated into HMR 52 were based on storms occurring west of the plains of eastern Colorado (p.l), ~ The PMP values should have been compared to the largest storms that have occurred in the region (p. 2). ~ Important characteristics of the largest storms observed in the region weren't fully considered (p, 2), ~ The NWS PMP is 60 percent larger than the maximized 1935 storm, rendering it implausible [the latter is implied] (p. 2). ~ The ratio ofNWS's PMP to the 100-yr depth of7 is neither plausible nor justified (p, 2), and a ration of about 2 may be more appropriate (p. 27). . If these comprise all the conclusions, the report is finished, The original 8/19/97 peer review by AWA indicated that only "general comments" could be made at that time because specific details and documents were not provided by NWS. Apparently all the requested details and documents were subsequently provided last June, allowing completion of this review. I expected to see a restatement of the "general" issues listed in the 1997 review, perhaps adding other specific issues to the list and addressing them, Some of the key issues appear to have been thoroughly assessed in Task 3, but the tone of the report doesn't convey finality. Conclusions regarding the most favorable PMP for use over Cherry Creek are not part of this task, but the final report should identify, assess, and "rule on" all the site-specific considerations that may have been improperly addressed in the NWS study, In the earlier 1997 review, A W A "ruled on" the study, conclucling that the NWS PMP study "lead to larger PMP values.. ,than would have resulted from a more detailed study." No similar or other conclusion is stated in the 12/1/01 report, Some form of concise statement regarding the final conclusions from the review is needed (possibly in Task 1), accompanied by a carefully-developed foundation for the conclusions (probably in Task 3), . Task 2: Additional analyses are planned to complete this task, and the task appears to be SO percent complete as stated. Comments on whether the requirements of this task have been met are deferred until the described analyses are completed and the draft report is distributed to us. . Task 3: This section of the report states that only preliminary discussions of sensitivities of the parameters are provided, and that a final report is pending, so we are not able to fully review the product. Task 3 is probably where all arguments regarding the contested NWS procedures will be developed and 022/