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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. A W A Team Study Approach The approach taken by the A W A team to determine site-specific PMP values for the Cherry Creek drainage is as follows: 1. Adhere to the published definition ofPMP. 2. Use a storm based analysis approach, incorporating the concepts of storm maximization, storm transposition, elevation and barrier moisture adjustments, and temporal and spatial envelopment. Emphasis is placed on using only storms that can be transpositioned over the northern slopes of the Palmer Divide. This constraint also applies to the use of methods, procedures and techniques that are consistent with storm characteristics of transpositionable storms, Implicit storm transpositioning is not used. Methods and techniques that attempt to address orographic effects in PMP analyses must be valid for storms that can occur over the Cherry Creek basin. When validated methods are not available, conservative assumptions are used. 3. Computer based Geographic Information System (GIS) technologies are incorporated to support accepted analysis methods and procedures. Emphasis is placed on incorporating as much objectivity as possible, following procedures as explicitly as possible and producing reproducible results. ) } The A W A team recognizes that the procedures used in the determination of PMP values for the Cherry Creek drainage basin must I) be physically possible and 2) replicate storm characteristics consistent with extreme storms that can occur over the northern slopes of the Palmer Divide. All assumptions made during the analysis need to be physically consistent with each other and with the atmospherics physics of an extreme rainfall storm environment over the Cherry Creek basin. The assumptions used in this study are presented in the following sections, 7