C150094 Red Mesa Ward Hydrology Study

• Contract/PO #: C150094
• Contractor Name: La Plata Water Conservancy District
• Contract Type: Grant
• County: La Plata
• Loan Projects - Doc Type: Report

- 50
ures 2.25 to 2.27, depth-
For the range of 6/24-hr ratios included in fig 2.7 . The re-
gional values in percent of 24-hr amounts are found indtanleig The were
gional ratio maps, and the depth-duration curves p
used in adjusting the major storm data to 24-hr amounts listed in table 7.1.
Table 2.7.
Durational variation of convergence PMP (in percent of 24-hr
amount) .
Duration (Hrs) 72
Duration (Hrs) 6 12 18 24 48
6 12 18 24 48 72 100 116 124
66 84 93 116 123
52 77 90 100 127 146 4
50 77 90 100 128 150 67 85 94 100 122
51 77 90 100 128 148 68 85 94 100 115
�9 86 94 100 115 1.21
53 77 91 100 127 144 114 120
54 78 91 100 126 142 70 87 94 100 114 119
56 78 91 100 125 140 71 87 95 100 118
56 79 91 100 123 138 72 88 95 100 113 118
57 79 92 100 123 137 73 88 95 100 113
58 80 92 100 122 135
59 80 92 100 121 134 74 89 95 100 112 117
75 89 96 100 112 116
111 115
76 90 96 100 115
60 81 92 100 120 132 77 90 96 100 110
61 81 92 100 120 131 78 91 96 100 110 114
62 82 93 100 119 129 79 92 97 100 109 113
63 82 93 100 11a 126 100 109 113
64 83 93 100 80 92 97
65 84 93 100 117 125 . figures
Note• For use, enter first column (6 hr) with 6/24-hr ratio from fig
2.25. to 2.27. .
2.5 Areal Reduction for Basin Size
For operational use, basin average values of convergence PIS are needed
2 values. Preferably, the method for reducing
rather than(26-km2) va (26-km2)) general storms in }
� 10-mil (26-km2) values to basin average rainfalls gerived from
depth-area relations ofest=oportionseoreorographic precipitation. t
the region include larg .P P
Our solution was to use generalized depth-area arelations developedtfoesP}
estimates within bordering zones in the Central
(Riedel et al. 1956) . The smoothed areal variations adopted for oheaSoum-
( figures 2.28 a
western States are shown in fig insignificant.
1 bination of months where differences are i (26-�2)
that reduuce 10-m 2 ry6nth•
Figures 2.28 and 2.29 give depth-area relatiQ�s12,950 lon ) for each
for basin sizes up to 5,000 mi4 ( )ho pea incre-
ments.Areal vervance pt's greatest (1st to 4th)
Ar variations are given for the 4 g sizeais required.
rents. After the 4th increment nobe reduction for basin
consideration of an
Application of these figures will
example of PMP computation in chap ter 6.i s
3
3
J