SW6201005_Supplement-EZ Form_20211103

Calculation:
For uniform lot sizes:
(SA: 838,966 W x DF: 0.24,)— ((RA: 51,735 ft) — (OA: 66,174 ft2) = BUA per Lot = 6,953 fe
(No of Lots: 12)
For non -uniform lot sizes:
a. (SA: W x DF: ) — (RA: fe) — (OA: ft) = Total allowable lot BUA = ft2
b. Total BUA from lot listing: sf. b must be < a
III. DESIGN INFORMATION
Complete the following table. If additional space is needed the information should be provided in the same
format as Table 1 and attached to this form. Rainfall intensity data can be found in Appendix 8.03 of the State
of North Carolina Erosion and Sediment Control Planning and Design Manual or at
http://hdsc.nws.noaa.gov/hdsc/pfds/
Table 1. Swale design information based on the 10-year storm.
Swale No.
Drainage
Area ac
Impervious
Area ac
Grassed
Area (ac)
C
Q
(cfs
Slope
%
Vallow
(fps)
Vactwl
(fps)
Flow
Depth (ft)
1
1.44
.46
0.93
.57
6.0
1.45
5.00
1.26
0.97
2
0.44
.27
.17
.85
2.73
7.21
5.00
1.67
0.47
3
1.83
.42
1.41
65
8.67
1 1.37
5.00
2.49
0.80
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Form SW401-Low Density -Rev. 3 -2/10/09 Page 2 of 4