SW3200601_02_SpeedwaySubstation_StormwaterLowDensityApplication_SIGNED_20201020

Form SW401-Low Density-Rev.3-2/10/09 Page 1 of 4
Permit No.
(to be provided by DEMLR)
State of North Carolina
Department of Environment and Natural Resources
Division of Energy, Mineral and Land Resources
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
LOW DENSITY SUPPLEMENT
This form may be photocopied for use as an original
A low density project is one that meets the appropriate criteria for built upon area and transports stormwater
runoff primarily through vegetated conveyances. Low density projects should not have a discrete stormwater
collection system as defined by 15A NCAC 2H .1002(18). Low density requirements and density factors can be
found in Session Law 2008-211, 15A NCAC 2H .1000, Session Law 2006-246 and the State of North Carolina
Stormwater Best Management Practice Manual. Curb and gutter systems are allowed provided they meet the
requirements in 15A NCAC 2H .1008(g).
I. PROJECT INFORMATION
Project Name : Speedway Substation
Contact Person: David Grubb, Jr. Phone Number: ( 415 )617-1449
Number of Lots:0 Allowable Built Upon Area (BUA) Per Lot*:0
Number of Dwelling Units Per Acre**:N/A%
Low Density Development (check one):without curb & gutter with curb & gutter, outlets to (check one):
Swales Vegetated Area
*If lot sizes are not uniform, attach a table indicating the number of lots, lot sizes and allowable built upon area for each lot.
The attachment must include the project name, phase, page numbers and provide area subtotals and totals. BUA shall be
shown in units of square feet.
**(Phase II Post-Construction [non-SA] only)
II. BUILT UPON AREA
Refer to DEMLR’s forms and applications website for specific language that must be recorded in the deed
restrictions for all subdivided projects. (http://portal.ncdenr.org/web/lr/state-stormwater-forms_docs)
Complete the following calculation in the space provided below where:
• SA Site Area - the total project area above Mean High Water.
• DF Density Factor - the appropriate percent built upon area divided by 100.
• RA Road Area - the total impervious surface occupied by roadways.
• OA Other Area - the total area of impervious surfaces such as clubhouses, tennis courts, sidewalks, etc.
• No. of Lots - the total number of lots in the subdivision.
• BUA per Lot - the computed allowable built upon area for each lot including driveways and impervious
surfaces located between the front lot line and the edge of pavement.
• Total allowable lot BUA - the computed allowable built upon area for all lots combined.
• Total BUA from lot listing - the sum of built upon area allocated for each lot on the list of non-uniform lots.
Calculation:
Form SW401-Low Density-Rev.3-2/10/09 Page 2 of 4
For uniform lot sizes:
(SA: 566,280 ft2 x DF: 0.1146) – (RA: 35,278 ft2) – (OA: 29,625 ft2) = BUA per Lot = 0 ft2
(No of Lots: 0)
For non-uniform lot sizes:
a. (SA: ft2 x DF: ) – (RA: ft2) – (OA: ft2) = 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)
Vactual
(fps)
Flow
Depth (ft)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
IV. REQUIRED ITEMS CHECKLIST