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<br />Findings and Recommendations <br /> <br />A W A Team PMP Determination <br /> <br />The largest Colorado rainfall storm centers that have occurred east of the foothills were <br />identified. These storm centers were maximized, transpositioned and barrier moisture adjusted <br />for the Cherry Creek: location on the north side of the Palmer Divide. The rainfall patterns of <br />each of these storm centers were rotated and critically centered over the basin for maximum <br />rainfall depths within the Cherry Creek: Basin before being clipped to the basin boundary. The <br />basin average rainfall amounts that were produced by applying these procedures are presented on <br />the next page. The Depth- Duration curves for these storm were then plotted and an smoothed <br />envelopment curve was drawn using the most critical rainfall rates. Additionally, the Depth- <br />Area curves were plotted for each storm and a spatially enveloped and smoothed curve was <br />drawn. Both of the envelopment curves are presented following the storm rainfall table. <br /> <br />A summary of the maximum rainfall values for the Cherry Creek: basin is provided <br />below: <br /> <br />Maximum 24- hour rainfall from adjusted storm rainfall <br />over the Cherry Creek: basin: <br />Temporally enveloped 24- hour rainfall over the <br />Cherry Creek: basin: <br />Spatially enveloped 24- hour rainfall over the Cherry Creek: <br />basin using the spatial envelopment adjustment <br />factor of 1.13: <br /> <br />13.54 inches <br /> <br />14.0 inches <br /> <br />15.8 inches <br /> <br />Storm durations for the 10 storm centers used were effectively limited to 24- hours or less. <br />In order to provide PMP values for the 72- hour duration, rainfall amounts were computed using a <br />10% increase of the 24- hour value for the additional 48- hour duration. This is a conservative <br />measure to extend the storm duration to 72- hours since no storms identified in the storm analyses <br />lasted 72- hours. The 10% increase is based on the increase in PMP values for the Cherry Creek: <br />basin location from the 24-hr value to 72-hr value for the 10 square mile area size in HMR 55A. <br /> <br />Maximum 72- hour rainfall after temporal and spatial envelopment: <br /> <br />17.4 inches <br />