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<br />- 3- <br /> <br />Comparison of the A W A 2003 Study Team & the NWS 1995 Study Team Results <br />Topic A W A 2003 Study Team NWS 1995 Studv Team <br />Basin Maximize, transposition, and apply barrier Use generalized PMP values from HMR <br />approach and elevation adjustments to Colorado 55A with procedures from HMR 52, modify <br /> storms for the Cherry Creek Basin the rainfall with orographic factor <br />Source of Storm analyses of Colorado storms, most HMR 55A (most recent storm 1978), HMR <br />rainfall data recent storm 1997 52 (storms east of 102.2 degrees west <br /> longitude) <br />Orographic Evaluate terrain slopes within and upwind Computer orographic adjustment factors for <br />influences of the Cherry Creek drainage basin to locations within the basin using ratios of <br /> identify upslope, level and downslope I DO-year point rainfall values <br /> regions <br />Storm Recomputed maximization factors for 1935 HMR 55A computed storm maximization <br />Maximization and 1965 storms, used published factors of factors <br /> other storms <br />Storm Only selected Colorado storms were trans- Storms used to establish HMR 55A PMP <br />Transposition positioned to the Cherry Creek basin values for the Cherry Creek basin were not <br /> exolicitly identified <br />Storm No constraints on storm centering within No constraints on storm centering within the <br />Centering the Cherry Creek basin boundaries Cherrv Creek basin boundaries <br />Storm HMR 55A orientation limits accepted HMR 55A orientation limits accepted <br />Orientation <br />Within Storm Critically centered and oriented observed Within I without rainfall distributions in <br />Rainfall Colorado storm rainfall patterns used for HMR 52 used. These were calculated from <br />Distributions distributions within the Cherry Creek mostly Midwest rainfall and east coast <br />(storm size) drainage basin boundaries storms (onlv I Colorado storm used) <br /> <br />Applied Weather Associates - Technical Review - Final Results <br /> <br /> <br />. miles basin <br /> <br />AWA <br />Neutral ~ 0% <br />N/A <br />-15% <br />64% <br />15.8 inches <br /> <br />NWS <br />N/A <br />K-factor+ 10% <br />? <br />81% <br />21.1 inches <br /> <br />Recommendations <br />The CWCB staffhas worked in close cooperation with all interested parties throughout this project <br />to come up with the best scientific answer that is conservative and defensible but representative of <br />the Cherry Creek Basin and Colorado climatological and hydrological characteristics. The CWCB <br />staff recommends that the CWCB Members endorse the Probable Maximum Precipitation (PMP) <br />Site-Specific Study for Cherry Creek Reservoir that was completed by the Applied Weather <br />Associates in August 2003. The CWCB staff further recommends that the CWCB Director present <br />the Boards endorsement of the Technical Review to the Cherry Creek Basin interests, sponsoring <br />communities, Colorado's Congressional Delegation, the US Army Corps of Engineers - Omaha <br />District and the Colorado General Assembly in response to Senate Joint Resolution 99-023. <br /> <br />Flood Protection. Water Project Planning and Finance. Stream and Lake Protection <br />Water Supply Protection. Conservation Planning <br />