County Probability of occurrence in any year
50% 20% 4% 2% 1% PMP
Allen 2.7 3.5 4.8 5.4 6.1 28.0
Anderson 2.7 3.5 4.8 5.3 6.0 27.8
Atchison 2.6 3.4 4.5 5.1 5.7 27.2
Barber 2.4 3.2 4.4 5.0 5.7 27.3
Barton 2.3 3.0 4.1 4.8 5.3 26.6
Bourbon 2.7 3.5 4.8 5.4 6.0 28.1
Brown 2.5 3.2 4.4 5.0 5.6 27.0
Butler 2.6 3.4 4.7 5.3 6.0 27.7
Chase 2.6 3.4 4.6 5.2 5.9 27.5
Chautauqua 2.7 3.5 4.9 5.5 6.2 28.3
Cherokee 2.8 3.6 5.0 5.5 6.2 28.5
Cheyenne 1.8 2.4 3.4 3.8 4.3 24.7
Clark 2.2 3.0 4.1 4.7 5.3 26.7
Clay 2.5 3.2 4.3 5.0 5.5 26.8
Cloud 2.4 3.1 4.2 4.8 5.4 26.6
Coffey 2.7 3.5 4.7 5.3 6.0 27.8
Comanche 2.3 3.1 4.2 4.9 5.5 27.0
Cowley 2.6 3.4 4.8 5.4 6.1 28.0
Crawford 2.8 3.6 4.9 5.4 6.1 28.3
Decatur 1.9 2.6 3.6 4.2 4.6 25.3
Dickinson 2.5 3.2 4.4 5.1 5.6 27.1
Doniphan 2.5 3.2 4.5 5.0 5.6 27.0
Douglas 2.6 3.4 4.6 5.2 5.8 27.5
Edwards 2.2 2.9 4.1 4.7 5.3 26.7
Elk 2.7 3.5 4.8 5.4 6.1 28.1
Ellis 2.1 2.9 3.9 4.6 5.0 26.2
Ellsworth 2.3 3.1 4.2 4.9 5.4 26.7
Finney 2.0 2.6 3.8 4.3 4.8 26.8
Ford 2.1 2.8 4.0 4.6 5.1 26.4
Franklin 2.7 3.5 4.7 5.2 5.9 25.8
Geary 2.5 3.2 4.4 5.1 5.7 27.1
Gove 2.0 2.6 3.7 4.3 4.7 25.7
Graham 2.0 2.7 3.8 4.4 4.8 25.8
Grant 1.9 2.6 3.7 4.2 4.7 25.6
Gray 2.0 2.7 3.9 4.4 4.9 26.1
Greeley 1.8 2.5 3.4 3.9 4.4 25.0
Greenwood 2.7 3.5 4.8 5.3 6.1 27.8
Hamilton 1.8 2.5 3.5 4.0 4.5 25.2
Harper 2.5 3.3 4.5 5.2 5.9 27.5
Harvey 2.5 3.3 4.5 5.1 5.8 27.4
Haskell 2.0 2.7 3.8 4.3 4.8 25.9
Hodgeman 2.1 2.8 3.9 4.5 5.0 26.3
Jackson 2.6 3.4 4.5 5.1 5.7 27.2
Jefferson 2.6 3.4 4.6 5.1 5.8 27.3
Jewell 2.3 2.9 4.0 4.7 5.1 26.3
Johnson 2.6 3.4 4.6 5.2 5.8 27.5
Kearny 1.9 2.6 3.6 4.1 4.6 25.5
Kingman 2.4 3.2 4.4 5.1 5.7 27.3
Kiowa 2.2 2.9 4.2 4.8 5.4 26.7
Labette 2.8 3.6 5.0 5.5 6.2 28.4
Lane 2.0 2.7 3.7 4.3 4.8 25.8
Leavenworth 2.6 3.4 4.6 5.1 5.8 27.4
Lincoln 2.3 3.0 4.2 4.8 5.3 26.6
Linn 2.7 3.5 4.8 5.3 6.0 27.9
Logan 1.9 2.5 3.6 4.1 4.6 25.3
Lyon 2.6 3.4 4.6 5.2 6.0 27.5
Marion 2.5 3.3 4.5 5.2 5.8 27.3
Marshall 2.5 3.2 4.3 4.9 5.5 26.8
McPherson 2.5 3.2 4.4 5.1 5.7 27.1
Meade 2.1 2.8 4.0 4.6 5.1 26.3
Miami 2.7 3.5 4.7 5.2 5.9 27.7
Mitchell 2.3 3.0 4.1 4.7 5.2 26.4
Montgomery 2.8 3.5 5.0 5.5 6.2 28.3
Morris 2.6 3.4 4.5 5.1 5.8 27.3
Morton 1.9 2.5 3.6 4.1 4.6 25.4
Nemaha 2.5 3.2 4.4 5.0 5.6 26.9
Neosho 2.7 3.5 4.9 5.5 6.1 28.2
Ness 2.1 2.8 3.9 4.5 4.9 26.1
Norton 2.0 2.6 3.7 4.3 4.7 25.6
Osage 2.6 3.4 4.6 5.2 5.9 27.5
Osborne 2.2 2.9 4.0 4.6 5.1 26.2
Ottawa 2.4 3.1 4.3 4.9 5.4 26.8
Pawnee 2.2 2.9 4.1 4.7 5.2 26.6
Phillips 2.1 2.8 3.8 4.4 4.9 25.8
Pottawatomie 2.5 3.2 4.4 5.0 5.6 27.0
Pratt 2.3 3.1 4.3 4.9 5.5 27.0
Rawlins 1.9 2.5 3.5 4.0 4.5 25.0
Reno 2.4 3.2 4.4 5.0 5.7 27.2
Republic 2.3 3.0 4.1 4.8 5.3 26.4
Rice 2.4 3.1 4.3 4.9 5.5 26.9
Riley 2.5 3.2 4.4 5.0 5.6 27.0
Rooks 2.1 2.8 3.9 4.5 4.9 26.0
Rush 2.2 2.9 4.0 4.6 5.1 26.4
Russell 2.2 2.9 4.1 4.7 5.2 26.5
Saline 2.4 3.1 4.3 5.0 5.5 26.9
Scott 1.9 2.6 3.6 4.2 4.7 25.5
Sedgwick 2.5 3.3 4.6 5.2 5.9 27.5
Seward 2.0 2.7 3.8 4.4 4.9 26.0
Shawnee 2.6 3.4 4.6 5.1 5.8 27.4
Sheridan 2.0 2.6 3.7 4.2 4.7 25.5
Sherman 1.8 2.4 3.4 3.9 4.4 24.8
Smith 2.2 2.9 3.9 4.6 5.0 26.1
Stafford 2.3 3.0 4.2 4.9 5.4 26.9
Stanton 1.9 2.5 3.6 4.1 4.5 25.3
Stevens 1.9 2.6 3.7 4.3 4.7 25.8
Sumner 2.6 3.4 4.7 5.3 6.0 27.8
Thomas 1.9 2.5 3.5 4.1 4.5 25.2
Trego 2.0 2.7 3.8 4.4 4.9 25.9
Wabaunsee 2.6 3.4 4.5 5.1 5.8 27.3
Wallace 1.8 2.4 3.4 3.9 4.4 24.9
Washington 2.4 3.1 4.2 4.9 5.4 26.6
Wichita 1.9 2.5 3.5 4.1 4.5 25.3
Wilson 2.7 3.5 4.9 5.4 6.1 28.1
Woodson 2.7 3.5 4.8 5.4 6.1 28.0
Wyandotte 2.6 3.4 4.6 5.1 5.8 27.4
Relative increase in rainfall amount for storm durations over six hours
Time (hours) 100-year ratio PMP ratio
6 1.000 1.000
6.5 1.019 1.013
7 1.035 1.025
7.5 1.051 1.037
8 1.066 1.048
8.5 1.081 1.058
9 1.094 1.068
9.5 1.108 1.078
10 1.120 1.087
10.5 1.132 1.096
11 1.144 1.104
11.5 1.155 1.112
12 1.166 1.120
13 1.187 1.134
14 1.207 1.148
15 1.225 1.161
16 1.243 1.173
17 1.259 1.185
18 1.275 1.196
20 1.305 1.217
22 1.333 1.236
24 1.359 1.254
Drainage Reduction ratio
area
(sq. mi.) Zone 1 Zone 2 Zone 3
10 1.00 1.00 1.00
12 0.99 0.99 0.98
15 0.97 0.95 0.93
17 0.96 0.94 0.91
20 0.94 0.91 0.88
22 0.93 0.90 0.86
25 0.92 0.88 0.83
27 0.92 0.87 0.82
30 0.91 0.86 0.80
35 0.90 0.84 0.77
40 0.88 0.82 0.75
45 0.87 0.80 0.72
50 0.86 0.78 0.70
60 0.84 0.75 0.65
70 0.82 0.72 0.62
80 0.80 0.70 0.59
90 0.79 0.68 0.57
100 0.78 0.67 0.55
Zone 1, zone 2, and zone 3 shall have the meanings specified in K.A.R. 5-40-1 under the definition of a "stream."
Kan. Admin. Regs. § 5-40-31