Spreadsheet: 2ab472de-63c8-4a95-83aa-65ba230efc4f
Sheet: Table

CONTRA COSTA COUNTY FLOOD CONTROL AND WATER CONSERVATION DISTRICT RAINFALL DISTRIBUTION COEFFICIENTS FOR VARIOUS DESIGN STORMS
DURATION | 3-HR |  | 6-HR |  | 9-HR 1 |  | 12-HR |  | 24-HR |  | 36-HR 1 |  | 48-HR 1 |  | 96-HR
INTERVAL | 15 minutes |  | 15 minutes |  | 15 minutes |  | 15 minutes |  | 30 minutes |  | 30 minutes |  | 30 minutes |  | 2 hours
 | Time (hr) | % of Total | Time (hr) | % of Total | Time (hr) | % of Total | Time (hr) | % of Total | Time (hr) | % of Total | Time (hr) | % of Total | Time (hr) | % of Total | Time (hr) | % of Total
1 | 0.25 | 3 | 0.25 | 2.1 | 0.25 | 1 | 0.25 | 0.9 | 0.5 | 0.87 | 0.5 | 1.1 | 0.5 | 0.7 | 2 | 0
2 |  | 2 |  | 2.5 |  | 2 |  | 0.9 |  | 0.87 |  | 1.3 |  | 0.7 |  | 0.1
3 |  | 5 |  | 3.8 |  | 2 |  | 1 |  | 0.88 |  | 1.4 |  | 0.7 |  | 0.7
4 |  | 2.8 |  | 4.5 |  | 2 |  | 1 |  | 0.88 |  | 1.5 |  | 0.7 |  | 1.6
5 |  | 8.8 |  | 6 |  | 3 |  | 1.1 |  | 0.92 |  | 1.5 |  | 0.8 |  | 1.4
6 |  | 10.2 |  | 3 |  | 2 |  | 1.1 |  | 0.98 |  | 1.8 |  | 0.8 |  | 3.6
7 |  | 5.5 |  | 2.3 |  | 2 |  | 1.1 |  | 1.07 |  | 2 |  | 0.8 |  | 5.6
8 |  | 7 |  | 2.5 |  | 3 |  | 1.2 |  | 1.13 |  | 2.2 |  | 0.9 |  | 4.1
9 |  | 10.5 |  | 4.8 |  | 4 |  | 1.2 |  | 1.18 |  | 2.5 |  | 0.9 |  | 2
10 |  | 11 |  | 4.3 |  | 3 |  | 1.2 |  | 1.22 |  | 3.4 |  | 0.9 |  | 0.6
11 |  | 27.7 |  | 2.6 |  | 2 |  | 1.3 |  | 1.23 |  | 4.6 |  | 1 |  | 0.4
12 |  | 6.5 |  | 2.5 |  | 2 |  | 1.5 |  | 1.27 |  | 12.4 |  | 1.1 |  | 0
13 |  |  |  | 2.2 |  | 2 |  | 1.6 |  | 1.41 |  | 6.2 |  | 1.2 |  | 0.1
14 |  |  |  | 2.5 |  | 2 |  | 1.6 |  | 1.69 |  | 3.8 |  | 1.2 |  | 0.2
15 |  |  |  | 5 |  | 1 |  | 1.7 |  | 1.86 |  | 3 |  | 1.3 |  | 0
16 |  |  |  | 7.9 |  | 2 |  | 1.7 |  | 1.94 |  | 2.4 |  | 1.3 |  | 0
17 |  |  |  | 19 |  | 2 |  | 1.9 |  | 2.5 |  | 2.2 |  | 1.4 |  | 0
18 |  |  |  | 6.3 |  | 2 |  | 2 |  | 3.5 |  | 2 |  | 1.5 |  | 0
19 |  |  |  | 4 |  | 2 |  | 2.3 |  | 4.9 |  | 1.6 |  | 1.7 |  | 0
20 |  |  |  | 3 |  | 3 |  | 3 |  | 21.2 |  | 1.5 |  | 2.2 |  | 1.1
21 |  |  |  | 2.5 |  | 3 |  | 3.2 |  | 6.8 |  | 1.5 |  | 2.4 |  | 0.4
22 |  |  |  | 2.4 |  | 3 |  | 4.1 |  | 4 |  | 1.4 |  | 3.1 |  | 4.7
23 |  |  |  | 2.2 |  | 3 |  | 4.9 |  | 3.25 |  | 1.3 |  | 3.7 |  | 3
24 |  |  |  | 2.1 |  | 4 |  | 14.6 |  | 2.85 |  | 1.1 |  | 10.9 |  | 3.6
25 |  |  |  |  |  | 4 |  | 6.1 |  | 2.52 |  | 0.3 |  | 4.5 |  | 2.4
26 |  |  |  |  |  | 5 |  | 3.6 |  | 2.28 |  | 0.3 |  | 2.7 |  | 3.6
27 |  |  |  |  |  | 7 |  | 3.1 |  | 2.03 |  | 0.4 |  | 2.3 |  | 5
28 |  |  |  |  |  | 6 |  | 2.8 |  | 1.77 |  | 0.4 |  | 2.1 |  | 4.4
29 |  |  |  |  |  | 5 |  | 2.6 |  | 1.62 |  | 0.4 |  | 1.9 |  | 4.4
30 |  |  |  |  |  | 4 |  | 2.1 |  | 1.58 |  | 0.4 |  | 1.6 |  | 4.4
31 |  |  |  |  |  | 3 |  | 2 |  | 1.53 |  | 0.4 |  | 1.5 |  | 3.3
32 |  |  |  |  |  | 2 |  | 1.8 |  | 1.47 |  | 0.4 |  | 1.3 |  | 4.7
33 |  |  |  |  |  | 2 |  | 1.7 |  | 1.42 |  | 0.5 |  | 1.3 |  | 13.7
34 |  |  |  |  |  | 2 |  | 1.7 |  | 1.38 |  | 0.5 |  | 1.3 |  | 3.6
35 |  |  |  |  |  | 2 |  | 1.6 |  | 1.33 |  | 0.5 |  | 1.2 |  | 4.6
36 |  |  |  |  |  | 1 |  | 1.6 |  | 1.27 |  | 0.6 |  | 1.2 |  | 4.4
37 |  |  |  |  |  |  |  | 1.3 |  | 1.22 |  | 0.7 |  | 1 |  | 3.4
38 |  |  |  |  |  |  |  | 1.2 |  | 1.18 |  | 0.7 |  | 0.9 |  | 1.5
39 |  |  |  |  |  |  |  | 1.2 |  | 1.12 |  | 0.8 |  | 0.9 |  | 0.9
40 |  |  |  |  |  |  |  | 1.2 |  | 1.08 |  | 0.8 |  | 0.9 |  | 0
41 |  |  |  |  |  |  |  | 1.2 |  | 1.03 |  | 1 |  | 0.9 |  | 0.2
42 |  |  |  |  |  |  |  | 1.1 |  | 0.97 |  | 1.3 |  | 0.8 |  | 1.2
43 |  |  |  |  |  |  |  | 1.1 |  | 0.93 |  | 1.8 |  | 0.8 |  | 1.1
44 |  |  |  |  |  |  |  | 1.1 |  | 0.87 |  | 5.5 |  | 0.8 |  | 0
45 |  |  |  |  |  |  |  | 1 |  | 0.83 |  | 2.4 |  | 0.7 |  | 0
46 |  |  |  |  |  |  |  | 1 |  | 0.77 |  | 1.5 |  | 0.7 |  | 0
47 |  |  |  |  |  |  |  | 0.9 |  | 0.73 |  | 1.1 |  | 0.7 |  | 0
48 |  |  |  |  |  |  |  | 0.9 |  | 0.67 |  | 1.1 |  | 0.7 |  | 0
49 |  |  |  |  |  |  |  |  |  |  |  | 0.9 |  | 0.3
50 |  |  |  |  |  |  |  |  |  |  |  | 0.9 |  | 0.3
51 |  |  |  |  |  |  |  |  |  |  |  | 0.8 |  | 0.4
52 |  |  |  |  |  |  |  |  |  |  |  | 0.7 |  | 0.4
53 |  |  |  |  |  |  |  |  |  |  |  | 0.7 |  | 0.4
54 |  |  |  |  |  |  |  |  |  |  |  | 0.6 |  | 0.4
55 |  |  |  |  |  |  |  |  |  |  |  | 0.6 |  | 0.4
56 |  |  |  |  |  |  |  |  |  |  |  | 0.6 |  | 0.5
57 |  |  |  |  |  |  |  |  |  |  |  | 0.5 |  | 0.5
58 |  |  |  |  |  |  |  |  |  |  |  | 0.5 |  | 0.5
59 |  |  |  |  |  |  |  |  |  |  |  | 0.5 |  | 0.6
60 |  |  |  |  |  |  |  |  |  |  |  | 0.5 |  | 0.7
61 |  |  |  |  |  |  |  |  |  |  |  | 0.5 |  | 0.8
62 |  |  |  |  |  |  |  |  |  |  |  | 0.4 |  | 0.8
63 |  |  |  |  |  |  |  |  |  |  |  | 0.4 |  | 1.1
64 |  |  |  |  |  |  |  |  |  |  |  | 0.4 |  | 2.9
65 |  |  |  |  |  |  |  |  |  |  |  | 0.4 |  | 1.4
66 |  |  |  |  |  |  |  |  |  |  |  | 0.4 |  | 1
67 |  |  |  |  |  |  |  |  |  |  |  | 0.4 |  | 0.8
68 |  |  |  |  |  |  |  |  |  |  |  | 0.4 |  | 0.7
69 |  |  |  |  |  |  |  |  |  |  |  | 0.4 |  | 0.6
70 |  |  |  |  |  |  |  |  |  |  |  | 0.4 |  | 0.6
71 |  |  |  |  |  |  |  |  |  |  |  | 0.3 |  | 0.5
72 |  |  |  |  |  |  |  |  |  |  |  | 0.3 |  | 0.5
73 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.5
74 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.5
75 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.5
76 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.4
77 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.4
78 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.4
79 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.4
80 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.4
81 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.4
82 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.4
83 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.4
84 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.4
85 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.3
86 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.3
87 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.3
88 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.3
89 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.3
90 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.3
91 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.3
92 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.3
93 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.2
94 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.2
95 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.2
96 |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.2
1 The rainfall distribution information for the 9-, 36- and 48-hour events is preliminary should not used for design and analysis unless specifically discussed with the FC District Hydrology Section.