SW3221101_Supplement-EZ Form_20231024

INFILTRATION SYSTEM
1 Drainage area number 1
2 1 Minimum required treatment volume cu ft c
GENERAL MDC FROM 02H.1050
3 Is the SCM sized to treat the SW from all surfaces at build-out? No
4 Is the SCM located away from contaminated soils? Yes
5 What are the side slopes of the SCM(H:V or enter"Vertical"for
trenches)? 3:1
6 Does the SCM have retaining walls,gabion walls or other
engineered side slopes? No
7 Are the inlets,outlets,and receiving stream protected from erosion
10- ear storm)? Yes
8 Is there an overflow or bypass for inflow volume in excess of the
design volume? Yes
9 lWhat is the method for dewatering the SCM for maintenance? Pump(preferred)
10 If applicable,will the SCM be cleaned out after construction? Yes
11 Does the maintenance access comply with General MDC 8? Yes
12 Does the drainage easement comply with General MDC(9)? Yes
13 If the SCM is on a single family lot,does(will?)the plat comply with
General MDC 10? N/A
14 Is there an O&M Agreement that complies with General MDC(11)? Yes
15 Is there an O&M Plan that complies with General MDC 12? Yes
16 IDoes the SCM follow the device specific MDC? Yes
17 lWas the SCM designed by an NC licensedprofessional? Te-sll
INFILTRATION SYSTEM MDC FROM 02H.1051
18 Proposed slope of the subgrade surface(%) 6%
19 jAre terraces or baffles provided? No
20 IType ofpretreatment: I Forebay
Soils Data
21 Was the soil investigated in the footprint and at the elevation of the
infiltrations stem? Yes
22 SHWT elevation(fmsl) 651.80
23 Depth to SHWT per soils report in 38.00
24 Ground elevation at boring in soils report(fmsl) 655.00
25 Is a detailed hydrogeologic study attached if the separation is
between 1 and 2 feet? N/A
26 ISoil infiltration rate(in/hr) 0.14
27 1 Factor of safety FS 2 is recommended): 2.00
Elevations
29 Bottom elevation fmsl 654 ft
30 IStorage elevation(fmsl) 654.36 ft
31 1 Bypass elevation fmsl 654.36
For Basins Only
32 113ottom surface area(ft) 24900 ft
33 IStorage elevation surface area(ft) 27125.ft
For Trenches Only
34 Length(ft)
35 Width ft
36 Perforated pipe diameter,if applicable(inches)
37 Number of laterals
38 Total length of perforated piping
39 Stone type,if applicable
40 IStone porosity(%)
41 Is stone free of fines?
42 11sthe stone wrapped in geotextile fabric?
43 1 Has at least one inspection port beenprovided?
Volumes/Drawdown
44 IDesign volume of SCM cu ft 10092 cf
45 ITime to draw down hours rs
ADDITIONAL INFORMATION
46 Please use this space to provide any additional information about the
infiltration system(s):
Forebay excluded from infiltration basin surface area. Total infiltration surface area
=24,900 sf,Forebay area= 2,160 sf
Desi n Volume=Basin Volume @ Elevation 654.36' low level drain invert
Infiltration 1 12:30 PM 10/24/2023