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150 <br /> Table 6.1.—General-storm PMP computations for the Colorado River and Great <br /> basin <br /> Drainage 0.4k, / n�� e /Dff CS/'/ Area 298S2 (km2) <br /> Latitude � <br /> ,3,°%S Longitude��Jof basin center <br /> Month _ <br /> Step Duration (hrs) <br /> 6 12 18 24 48 72 <br /> A. Convergence PMP <br /> 1. Drainage average value from <br /> one of figures 2.5 to 2.16 /. in. (mm) <br /> • <br /> 2. Reduction for barrier- <br /> elevation [fig. 2.18] z <br /> 3. Barrier-elevation reduced ir 03 <br /> PMP [step 1 X step 21 =in. (mm) <br /> 4. Durational variation <br /> (figs. 2.25 to 2.27 7.5-Q� /� //,/ fly <br /> and table 2.71. o?� __7 <br /> 5. Convergence PMP for indicated <br /> durations [steps 3 X 41 �.Z S'z sz zz in. (mm) <br /> 6. Incremental 10 mil (26 km2) <br /> PMP [successive subtraction <br /> in step 5] 0.S D_3 0,9 003 in. (mm) <br /> 7. Areal reduction [select from <br /> figs. 2.28 and 2.29] 9B /D4 /m/4, /4l)z <br /> 8. Areally reduced PMP [step 6 X <br /> step 7] �Z Si'•S0.3 0,9am in. (mm) <br /> 9. Drainage average PMP (accumulated <br /> values of step 81 .S(e . L.S. Z[ in. (m°) <br /> B. Orographic PMP <br /> 1. Drainage average orographic index from figure 3.11a to d. 9,5-in.(mm) <br /> 2. Areal reduction [figure 3.201 9R z <br /> 3. Adjustment for month [one of <br /> figs. 3.12 to 3.17j 14LX <br /> 4. Areally and seasonally adjusted <br /> PMP (steps 1 X 2 X 31 in. (mm) <br /> 5. Durational variation [table <br /> 32 s9 a1 dal la./77z <br /> 6. Orographic PMP for given dur- <br /> ations [steps 4 I. 51 it.e 2 31 ILI in• (mm) <br /> C. Total PMP <br /> 1. Add steps A9 and B6 Z7 gd,z62,3 /3f/19 in. (mm) <br /> 2. PMP for other durations from smooth curve fitted to plot of computed data. <br /> 3. Comparison with local-storm PMP (see sec. 6.3). <br />