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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />Wind data was obtained from the State Climatologist using a variety of weather stations from the <br />CoAgMet network. The five stations closest to Empire reservoir were chosen for this analysis, see <br />Figure 6. Station data was analyzed to determine the maximum wind gust and maximum i-hour mean <br />wind speed. A description of this data for each station is listed below. <br /> <br />Table 1. Wind Data Summary by Station <br /> <br /> Peak 1 hr <br /> Data Range Wind <br />Station Speed Peak Gust <br /> Start End (mph) (mph) <br />Fort Morgan 4/21/1995 11/8/2007 42.3 60.4 <br />Wiggens01 4/1/1997 11/1/2004 38.2 47.5 <br />Wiggens02 4/1/1997 8/1/2005 41.7 49.2 <br />Kersey 5/1/1992 11/8/2007 43.5 54.3 <br />Briggsdale 1/1/2002 11/8/2007 38.1 49.8 <br /> <br />Maximum <br /> <br />44 <br /> <br />60 <br /> <br />Design <br />(FOS=1.1) <br /> <br />48 <br /> <br />66 <br /> <br />Design wind speeds used a factor of safety of 1.1. This number was selected after further examining the <br />number of wind events close to the maximums listed in Table 1. Figures 7 and 8 in Appendix B depict <br />the number of readings for the mean i-hour wind speed and the peak gust divided into various wind <br />speed categories. Analysis of the hourly data reveals that there have only been 2 independent events <br />with a mean i-hour wind speed that exceeds 40 mph and only one event with a peak gust exceeding 60 <br />mph. Therefore, the mean i-hour wind speed used for design is 48 mph and the one minute duration is <br />66 mph. The i20-minute duration wind was defined as 96% of the i-hour duration wind speed. Figures <br />9 and 10 in Appendix B show the distribution of mean i-hour winds speed and peak gust with respect to <br />wind direction. These figures reveal that the maximum winds occur out of the Northwest (270-360 <br />degrees), however, this analysis uses the design values listed in Table 2 regardless of the dam <br />orientation and therefore is considered conservative. The design wind speeds were adjusted using a <br />calculated water to land ratio. <br /> <br />Next, the design methodology described in the spreadsheet was followed to calculate the significant <br />wave height and wave run-up for each section. The significant wave heights were then used along with <br />a slope angle of 3H:i V and an assumed specific gravity of 2.5 to calculate the mean rock diameter, 050, <br />The results of this analysis are shown below in Table 2. <br /> <br /> <br />Empire Reservoir East Embankment Dam, Water Division 1 <br />DAMID 010728 <br /> <br />Page 4 <br />