SW3240202_Stormwater Report_20240212

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFORMATION
1 Project Name Rowan 85 Trade Center
2 Project Area(ac) 91.56
3 Coastal Wetland Area(ac) 0
4 Surface Water Area(ac) 0
5 Is this project High or Low Density? High
6 Does this project use an off-site SCM? No
COMPLIANCE WITH 02H.1003(4)
7 _Width of vegetated setbacks provided(feet) 30
8 Will the vegetated setback remain vegetated? Yes
9 If BUA is proposed in the setback,does it meet NCAC 02H.1003(4)(c-d)? Yes
10 Is streambank stabilization proposed on this project? No
NUMBER AND TYPE OF SCMs:
11 Infiltration System
12 Bioretention Cell
13 Wet Pond
14 Stormwater Wetland •
15 Permeable Pavement
16 Sand Filter _ 3
17 Rainwater Harvesting(RWH)
18 Green Roof
19 Level Spreader-Filter Strip(LS-FS)
20 Disconnected Impervious Surface(DIS) -
21 Treatment Swale
22 Dry Pond
23 StormFilter
24 Silva Cell
25 Bayfilter _
26 Filterra
FORMS LOADED
DESIGNER CERTIFICATION
27 Name and Title: Austin Watts,P.E./Vice President
•
28 Organization: Kimley-Horn and Associates
29 Street address: 200 South Tryon Street,Suite 200
_30 City,State,Zip: Charlotte,NC 28202
31 Phone number(s): 704-319-5698
32 Email: [e-mail]
Certification Statement:
I certify,under penalty of law that this Supplement-EZ form and all supporting information were prepared under my direction or supervision;that
the information provided in the form is,to the best of my knowledge and belief,true,accurate,and complete;and that the engineering plans,
specifications,operation and maintenance agreements and other supporting information are consistent with the information provided here.
Designer
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DRAINAGE AREAS
1 Is this a high density project? Yes
2 If so,number of drainage areas/SCMs 3
3 Does this project have low density areas? No
4 If so,number of low density drainage areas 0
Is all/part of this project subject to previous rule
5 versions? No
FORMS LOADED
DRAINAGE AREA INFORMATION Entire Site 1 2 3
4 Type of SCM Sand Filter Sand Filter Sand Filter
5 Total drainage area(sq ft) 3507451 1122541 781902 1603008 _
6 Onsite drainage area(sq ft) 3207758 904741 781902 1521115
7 Offsite drainage area(sq ft) 299693 217800 0 81893
8 Total BUA in project(sq ft) 2763882 sf 760122 sf 740520 sf 1263240 sf
New BUA on subdivided lots(subject to
9 permitting)(sq ft) N/A N/A N/A N/A
New BUA not on subdivided lots(subject to
10 permitting)(sf) 2763882 sf 760122 sf 740520 sf 1263240 sf
11 Offsite BUA(sq ft) sf N/A N/A N/A
12 Breakdown of new BUA not on subdivided lots:
-Parking(sq ft) 410160 sf 110280 sf 94800 sf _ 205080 sf
-Sidewalk(sq ft) _ 17426 sf 5126 sf N/A 12300 sf
-Roof(sq ft) _ 1236600 sf 332640 sf 451980 sf 451980 sf
-Roadway(sq ft) 1141078 sf 312076 sf 235122 sf 593880 sf
-Future(sq ft) N/A N/A N/A N/A
-Other,please specify in the comment box
below(sq ft) N/A N/A N/A N/A
New infiltrating permeable pavement on
13 subdivided lots(sq ft) N/A N/A N/A N/A
New infiltrating permeable pavement not on
14 subdivided lots(sq ft) N/A N/A N/A N/A
Existing BUA that will remain(not subject to
15 permitting)(sq ft) N/A N/A N/A N/A
16 Existing BUA that is already permitted(sq ft) N/A N/A N/A N/A
17 Existing BUA that will be removed(sq ft) 7775 sf 7775 sf sf sf
18 Percent BUA 68% 95% 79%
19 Design storm(inches) 1.0 in 1.0 in 1.0 in
20 Design volume of SCM(cu ft) 46265 cf 44098 cf 76067 cf
21 Calculation method for design volume Simple Simple Simple
ADDITIONAL INFORMATIO
Please use this space to provide any additional information about the
22 drainage area(s):

SAND FILTER
1 Drainage area number 1 2 3
2 Minimum re•uired treatment volume cu ft 46265 sf 44098 sf 76067 sf
GENERAL MDC FROM 02H.1050
3 Is the SCM sized to treat the SW from all surfaces at build-out? Ye; Yec Ye;
4 Is the SCM located away from contaminated soils? Yes Yes Yes
5 What are the side slopes of the SCM(H:V)? 3:1 3:1 3:1
6 Does the SCM have retaining walls,gabion walls or other No No Yes
engineered side slopes?
7 Are the inlets,outlets,and receiving stream protected from erosion Yes Yes Yes
(10-year storm)?
8 Is there an overflow or bypass for inflow volume in excess of the Yes Yes Yes
design volume?
9 What is the method for dewatering the SCM for maintenance? Drawdown Orifice Drawdown Orifice Drawdown Orifice
10 If applicable,will the SCM be cleaned out after construction? Yes Yes Yes
11 Does the maintenance access comply with General MDC(8)? Yes Yes Yes
12 Does the drainage easement comply with General MDC(9)? Yes Yes Yes
13 If the SCM is on a single family lot,does(will?)the plat comply with N/A N/A N/A
General MDC(10)?
14 Is there an O&M Agreement that complies with General MDC(11)? Yes Yes Yes
15 Is there an O&M Plan that complies with General MDC(12)? No No No
16 Does the SCM follow the device specific MDC? Yes Yes Yes
17 Was the SCM designed by an NC licensed professional? Yes Yes Yes
SAND FILTER MDC FROM 02H.1056
18 SHWT elevation(fmsl) 779 775 776.7
19 Type of sand filter(open or closed) Open r Open 1 Open
20 If closed,will the filter will be pre-cast or pour-in-place?
21 If closed,top of grate elevation(fmsl)
22 Is this sand filter designed to attenuate peak flows? Yes Yes Yes
Sediment Chamber
23 Volume that can be retained in the sediment chamber(cubic feet) 157306 cf 59197 cf 399030 cf
24 Will there be a permanent pool in the sediment chamber? No No No
25 Bottom of the sediment chamber(fmsl) 785.00 786.00 782.00
26 Area of the sediment chamber(square feet) 14831 sf 3645 sf 92100 sf
27 Physical depth of the sediment chamber(inches) 84 in 84 in 48 in
28 Ponding depth in the sediment chamber,above any permanent 60 in 68 in 32 in
pool(inches)
29'Elevation of top of weir between chambers(fmsl) 786.5 789.2 783.5
Sand Chamber
30 Volume that can be retained in the sand chamber(cubic feet) 98934 cf 54128 cf 90963 cf
31 Bottom of the sand chamber(fmsl) 785.00 786.00 782.00
32 Area of the sand chamber(square feet) 9393 sf 4125 sf 18740 sf
33 Physical depth of the sand chamber(inches) 84 in 84 in 48 in
34 Ponding depth in the sand chamber,above the sand surface 60 in 68 in 32 in
(inches) _
35 Elevation of the bypass device(fmsl) 782.5 780 778
36 Type of bypass device Underdrains Underdrains Underdrains
37 Mechanism for distributing flow over the sand surface Gravity Gravity Gravity
38 Sand specification for sand chamber Per ASTM C33 Per ASTM C33 I Per ASTM C33
39 Depth above underdrain pipe(inches) 18 in 18 in 18 in
40 Will the media be maintained to drain at least two inches per hour at Yes Yes Yes
the sand surface?
41 Is at least one clean-out pipe provided at the low point of each Yes Yes Yes
underdrain line?
42 Will clean-out pipes be capped? Yes Yes Yes
ADDITIONAL INFORMATION
Please use this space to provide any additional information about
43 the sand filter(s):
Ponding depths provided are for the 10-year event.
Sand Filter 3 9:31 AM 1/31/2024