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e e e - 3- HMR 55A reproduction: CWCB Freedom ofInformation Act used at the request ofthe National Weather Service as a formality. A W A reviewed HMR 55A for additional information and concluded that insufficient information was given to reproduce the 1995 NWS Site Specific PMP Study values. A W A used storm data from 10 extreme Colorado storms. Evaluate the use ofHMR 52 including storm centering, storm orientation, shape ratio, spatial distribution that compared the 29 storms to the Colorado storms (within/without curves). Tomlinson evaluated the HMR 52- 29 storms and believes that they are different than Colorado storms and HMR 52 should not be used in Colorado. He also believes that an evaluation ofk-factor use is appropriate. Tomlinson showed a radiating profile fan map; a 3-D map of inflow wind directions into the basin centroid. He showed the cross section from the northeast to the southwest. He also showed chart of upslope / down slope gradients. K-factors: storm inflow winds are down slope and k-factors are not justified for Cherty Creek basin. A W A evaluated the meteorological consistencies; storm orientation; went over storm physics for meeting participants. A W A used only Colorado storms - 10 storms; basin average site-specific PMP rainfall is 24 hour = 14 inches; for 72 hours 15.4 inches. 24-hour rainfall is given because this is considered the main flood results from the main portion of the storm. Presentation by John Henz. HDR Mr. John Henz followed the Tomlinson presentation and he discussed: (1) Review the temporal characteristics of the key Colorado extreme storms (2) Development a storm mass curve (3) Identification of key meteorological relationships, ie, "physically possible", that is the intent ofthe PMP definition. Henz presented information about the relationship of rainfall pattern, cloud layer steering winds and inflow winds. The rainfall pattern sets up major axis along the direction of cloud layer winds = +/- 10 degrees Low-level winds are 40-90 degrees to right of the cloud layer winds. The major impact on storm rainfall pattern trans-positioning defines "physically possible" scenarios in Colorado. Second presentation by Ed Tomlinson. A W A A W A procedure: Transpose the 10 largest Colorado storms into the Cherty Creek basin then maximized the stonns; adjust the rainfall amount for changes in atmospheric moisture; enveloping for rainfall timing; centered the stonn; critically aligned; kept the pattern shape for each stonn. Graphics and discussion used to depict this by A W A were: ?? Showed the ten events and their average rainfall depths. ?? Showed the isohyetal map of the Penrose / Pueblo stonn. ?? Showed map of the trans, clipped to the basin. ?? Showed the isohyetal of the plum creek 1965 storm ?? Showed trans map of 1965 stonn. ?? Described the maximization process for the Penrose stonn. ?? Showed the mass curve and the enveloping curve for the combined 14 Colorado stonns. ?? Showed the mass curve and enveloping curve for the June 16fu and 17th stonns. ?? Described the comparisons of approach between NWS and A W A. Ouestions from the l!roup: John Liou , FEMA Region vm - Mr. Liou asked why historical data is always used for PMP studies, and wondered if it is always the maximum? Historical data could be changed tomorrow if we get a big stonn in this area. He also expressed concerns over the PMP from the standpoint of the technical defmition of PMP including the word, 'theoretical' in it. The main argument being that does the methodology employed by A W A and the National Weather Service of using historical storms encompassing the range of what is 'theoretically' possible. The response by A W A was that the PMP methodology had employed an adjustment factor, which was meant to account for factors that go beyond that of the observed stonns in place. Flood Protection? Water Project Planning and Finance? Stream and Lake Protection Water Supply Protection? Conservation Planning