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<br />(' <br />r <br /> <br />(- <br /> <br />c. <br />( <br />(- <br />( <br />(, <br />c <br /> <br />( <br />, <br /> <br />( <br /> <br />l <br />( <br /> <br />\ <br />( <br /> <br />L <br />L <br />~. <br /> <br />" <br /> <br />c <br /> <br />\-- <br /> <br />'. <br /> <br />B. Design Flood Study and Routing <br /> <br />Exhibit 26 shows the hydrograph of the latest inflow design flood, <br />i:pproved in February 1964, and having an instantaneous peak inflow of <br />631 m3/s (27 300 ft3/sl under a IS-day volume of 1.49 by lOB m3 <br />(120 6bO acre-ftl. This flood was based on an in-place analysis of the <br />storm on Apri 1 14-16. 1921. Thi s storm was assumed to produce a <br />total 22!-hour rainfall of 156 mm (6.14 in) on the 484 km2 (187 mi2) <br />of lake Granby drainage area atiove Shadow Mountain lake, and a total <br />24-hour rainfall of 186 mm (7.31 inl on the 321 km2 (124 mi2) of <br />drainage area between Shadow Mountain lake and lake Granby. The inflow <br />desi gn fl ood was determi ned by addi ng the runoff resulti n <br />..tl2J:m, to the hi hest snow flood recorded at t e age, which <br />~ ~ f~June wlth a maXlmum mean al y flow of 113.2 m3/s <br />When routed through lake Granby with the water surface <br />~ va ion 2523.74 m (R7RO ftl--toD of ~illw~y gates--the outflow was <br />determined to be 351.8 m3/s (12 430 ft Isl at a maximum water sur- <br />face elevation of 2523.89 m (8ZtiU.4ti ttl. <br /> <br /> <br />64 <br />