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<br />Technical Review Panel Member Louis C. Schreiner Review Comments dated <br />April 16, 2003 <br /> <br />The primary comments from Mr. Schreiner address the attempt by the A W A team to <br />account for the differences between the A W A team site-specific study and the NWS 1995 study. <br />Mr. Schreiner states that barrier moisture depletion adjustments were applied in the HMR 55A <br />analysis and therefore should not be applied again to adjust the NWS PMP values. The explicit <br />barrier adjustments incorporated in the HMR 55A are not discussed in HMR 55A nor were they <br />explicitly discussed in the NWS For material. If appropriate barrier adjustments were <br />incorporated into HMR 55A, then an additional adjustment should not be made. <br /> <br />Mr. Schreiner agrees with the A W A team concern that the use of HMR 52 within the <br />HMR 55A region was inappropriate. His estimate of the impact of using HMR 52 is that the <br />PMP values should be 5 to 10 percent lower instead of the 21% as suggested by the AW A team. <br />We accept his opinion but have no basis for the 5-10% change. He suggests that much additional <br />study is needed but that level of effort is well beyond the scope of the current study. <br /> <br />Authors ofHMR 55A determined that minimum orographic rainfall could be produced in <br />the Cherry Creek basin. We agree that for the most part, the barriers surrounding the Cherry <br />Creek basin are minimal compared to the "extended steep slope barriers located some 10 to 12 <br />miles west of the Cherry Creek basin.". These steeper slopes are certainly associated with <br />orographic rainfall but are downwind of the Cherry Creek basin and do not influence rainfall <br />over the basin. The A W A team found no justification for any enhancement of rainfall due to the <br />topography within or surrounding the basin but did identify downslope (decreased rainfall) <br />regions. Furthermore, no breaks in the upwind barrier(s) surrounding the Cherry Creek basin <br />were identified. Not having identified any mechanism for topographically induced rainfall <br />enhancement, the A W A team finds no reason to increase the rainfall due to orographic <br />influences. <br /> <br />Additional Comments: <br />1. John......olease address these issues <br /> <br />2. Mr. Schreiner identified the omission of depth-area envelopment in the procedure <br />used for the Cherry Creek site-specific PMP study. He is correct. Depth-area <br />envelopment will be added to the A W A team procedure. <br /> <br />3. Discussion related to adjustments to point rainfall values from the NWS study have <br />been omitted in an effort to use basin average rainfall amounts in all discussion. <br /> <br />Summary <br />The A W A team appreciates Mr. Schreiner's review comments and his concurrence that <br />the use ofan appropriate applications manual instead of the use ofHMR 52 would be useful. <br />