20180119 Ver 2_2017-00911 Oct 2018 Estimated Flow Summary_20181101

Summary of Flow Estimates Under Several Conditions at Proposed Intake Location
Estimated Flows at Proposed Intake Location (cfs), using 5.34 square mile watershed
Mean
Jan
26.3
Feb
31.1
Mar
31.3
Apr
27.4
May
21.3
Jun
16.9
Jul
12.8
Aug
11.5
Sep
9.5
Oct
10.8
Nov
15.0
Dec
21.8
Annual
19.7
Percentile - 5
8.6
12.5
13.5
12.9
10.4
7.4
5.4
4.2
3.9
3.6
4.5
6.7
5.0
Percentile - 10
10.6
14.4
16.2
14.7
12.0
8.7
6.4
5.1
4.5
4.1
5.3
8.1
6.0
Percentile - 20
14.5
17.8
19.6
17.8
13.9
10.5
7.6
6.0
5.3
5.1
6.7
10.3
8.3
Percentile - 40
20.5
22.7
24.6
22.1
16.8
12.6
9.3
8.3
6.7
6.8
9.9
15.2
13.0
Percentile - 50
22.8
25.4
27.0
24.6
18.7
13.9
10.7
9.4
7.5
8.2
11.6
17.9
15.6
Percentile - 60
25.6
28.5
30.3
27.1
20.7
15.6
11.8
10.6
8.6
9.7
13.7
20.5
18.7
Percentile - 80
33.4
39.5
38.6
34.2
26.0
20.9
16.5
14.6
12.0
14.3
20.6
28.9
27.2
Percent of Estimated Flows Comprised by 2.23 cfs (%)
Mean
Jan
8.5
Feb
7.2
Mar
7.1
Apr
8.1
May
10.5
Jun
13.2
Jul
17.5
Aug
19.4
Sep
23.4
Oct
20.7
Nov
14.9
Dec
10.2
Annual
11.3
Percentile - 5
25.9
17.9
16.5
17.2
21.5
30.1
41.1
53.7
56.7
61.6
49.8
33.1
44.2
Percentile - 10
21.1
15.5
13.8
15.1
18.7
25.5
34.7
44.2
49.2
54.1
42.5
27.5
36.9
Percentile - 20
15.3
12.5
11.4
12.6
16.0
21.2
29.4
37.4
41.9
43.6
33.5
21.6
26.8
Percentile - 40
10.9
9.8
9.1
10.1
13.3
17.7
24.0
27.0
33.5
32.8
22.5
14.7
17.2
Percentile - 50
9.8
8.8
8.3
9.1
12.0
16.0
20.9
23.7
29.8
27.1
19.2
12.5
14.3
Percentile - 60
8.7
7.8
7.4
8.2
10.8
14.3
18.9
21.0
25.8
22.9
16.3
10.9
11.9
Percentile - 80
6.7
5.6
5.8
6.5
8.6
10.7
13.5
15.3
18.5
15.6
10.8
7.7
8.2
25 Percent of Flow is X cfs (cfs)
Mean
Jan
6.56
Feb
7.78
Mar
7.81
Apr
6.86
May
5.32
Jun
4.23
Jul
3.19
Aug
2.88
Sep
2.38
Oct
2.69
Nov
3.74
Dec
5.45
Annual
4.92
Percentile - 5
2.16
3.12
3.39
3.24
2.59
1.86
1.36
1.04
0.98
0.91
1.12
1.68
1.26
Percentile - 10
2.64
3.61
4.04
3.69
2.99
2.18
1.61
1.26
1.13
1.03
1.31
2.03
1.51
Percentile - 20
3.64
4.46
4.89
4.44
3.49
2.63
1.90
1.49
1.33
1.28
1.67
2.59
2.08
Percentile - 40
5.13
5.68
6.16
5.53
4.20
3.15
2.33
2.06
1.66
1.70
2.48
3.80
3.25
Percentile - 50
5.70
6.35
6.75
6.15
4.67
3.48
2.67
2.36
1.87
2.06
2.90
4.47
3.89
Percentile - 60
6.41
7.13
7.57
6.78
5.17
3.91
2.96
2.66
2.16
2.43
3.42
5.13
4.68
Percentile - 80
8.36
9.88
9.65
8.56
6.50
5.22
4.13
3.65
3.01
3.59
5.16
7.23
6.81
When 25% of flow is below 2.23 cfs

35 Percent of Flow is X cfs (cfs)
Mean
Jan
9.19
Feb
10.89
Mar
10.94
Apr
9.60
May
7.44
Jun
5.92
Jul
4.46
Aug
4.03
Sep
3.34
Oct
3.77
Nov
5.24
Dec
7.63
Annual
6.88
Percentile - 5
3.02
4.37
4.74
4.53
3.62
2.60
1.90
1.45
1.38
1.27
1.57
2.36
1.76
Percentile - 10
3.70
5.05
5.65
5.16
4.18
3.06
2.25
1.77
1.59
1.44
1.84
2.84
2.11
Percentile - 20
5.09
6.24
6.85
6.22
4.88
3.69
2.65
2.09
1.86
1.79
2.33
3.62
2.92
Percentile - 40
7.19
7.96
8.62
7.75
5.88
4.41
3.26
2.89
2.33
2.38
3.47
5.32
4.54
Percentile - 50
7.98
8.89
9.45
8.61
6.53
4.87
3.74
3.30
2.62
2.88
4.06
6.25
5.45
Percentile - 60
8.97
9.99
10.60
9.50
7.23
5.47
4.14
3.72
3.02
3.40
4.78
7.18
6.56
Percentile - 80
11.70
13.84
13.51
11.98
9.10
7.30
5.79
5.11
4.21
5.02
7.22
10.12
9.53
When 35% of flow is below 2.23 cfs
10 Percent of Flow is X cfs (cfs) - Remaining flow in stream per 1992 Memo
Mean
Jan
2.63
Feb
3.11
Mar
3.13
Apr
2.74
May
2.13
Jun
1.69
Jul
1.28
Aug
1.15
Sep
0.95
Oct
1.08
Nov
1.50
Dec
2.18
Annual
1.97
Percentile - 5
0.86
1.25
1.35
1.29
1.04
0.74
0.54
0.42
0.39
0.36
0.45
0.67
0.50
Percentile - 10
1.06
1.44
1.62
1.47
1.20
0.87
0.64
0.51
0.45
0.41
0.53
0.81
0.60
Percentile - 20
1.45
1.78
1.96
1.78
1.39
1.05
0.76
0.60
0.53
0.51
0.67
1.03
0.83
Percentile - 40
2.05
2.27
2.46
2.21
1.68
1.26
0.93
0.83
0.67
0.68
0.99
1.52
1.30
Percentile - 50
2.28
2.54
2.70
2.46
1.87
1.39
1.07
0.94
0.75
0.82
1.16
1.79
1.56
Percentile - 60
2.56
2.85
3.03
2.71
2.07
1.56
1.18
1.06
0.86
0.97
1.37
2.05
1.87
Percentile - 80
3.34
3.95
3.86
3.42
2.60
2.09
1.65
1.46
1.20
1.43
2.06
2.89
2.72
Estimated 7Q10 = 1.7 cfs USGS Estimates for 5.25 square mile watershed in Macon County
1 cfs = 448.8326 gpm 7Q10 is 1.6 to 4.4 cfs (ave. 2.6 cfs, median 2.4 cfs)
2.23 cfs = 1,000 gpm, Applicant proposed required flow 30Q2 is 3.2 to 7.1 cfs (ave. 4.7 cfs, median 4.5 cfs)
1.7 cfs = 763 gpm Ave. annual discharge is 12.7 to 20.4 (both ave. and median 15.8 cfs)
0.5 cfs =224 gpm
7Q10 - the lowest average flow that occurs for seven consecutive days with a recurrence probability of once every 10 years.
Flows equal to the 7Q10 generally occur during drought.
Annual 30 -day Minimum Flow - the lowest 30 -day mean flow calculated as a moving average for every 30 -day period that is completely
within the water year.
September Median - the monthly median flow for September. The September median flow has sometimes been used as a minimum flow
in the Southeast because September is typically the month with the lowest monthly median flow.
Monthly Median - In general hydrologic terms the middle flow value for the rank ordered flows for all years of a month (i.e. the 50th percentile).
Extreme low flow approximately 10th percentile
Low flow approximately 25th percentile
Median flow approximately 50th percentile
High flow approximately 75th percentile