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11010 Raven Ridge Road - Raleigh, Norgi Carolina 27614 9 Phone: [phone] * Fax: (919) 81"1

Tableof Contents ................................................................................................................. i
Listof Figures ....................................................................................................................... i|
Listof Appendices ................................................................................................................ ii
Stormnuxater Management Plan .......................................................................................... I
Nitrogen Export Calculations .............................................................................................. 2
Limitations..----....---.--..—,,__,,___,,,,,,,_,_,,,,_,,,_,___.3
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List of Figures
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The proposed Stormwater Management Plan (SMP) described in further detail belo
consists of the following components: i
The construction of a small retrofit bioretention area to provide stormwater
treatment for a portion of the impervious area near the front of the property.
The proposed bioretention area will provide treatment for approximately 465
square feet of impervious surface to offset the approximately 335 square feet of
impervious surface that discharges into the buffer.
The rerouting of roof gutters and associated downspouts (with splash-pads) to
discharge the majority of the rooftop runoff outside of the buffer.
3. The planting of unvegetated portions of the Zone 1 and Zone 2 of the buffer with
native shrub species.
Agreed upon conditions of the variance also include mitigation in the form of the
Payment of Nutrient Offset Mitigation for a total of 4.63 lbs./ac./yr. or an
estimated offset payment of $704.57 (at current NCEEP rates). See the
description below and Nitrogen Export calculations in Appendix A.
2. Payment of Buffer Mitigation in the amount of 2,938.50 square feet. See the
Statement of Availability in Appendix B.
Stormwater Management Plan
^

Nitrogen Export Calculations
Nutrient offset in the form of Total Nitrogen (TN) buy down is required by the Division
if Water Quality (DWQ) as part of the project's permitting requirements. We estimated
Nitrogen Export rates associated with the existing site conditions and proposed site
2

conditions using methods outlined in the Neuse River Basin: Model Stormwater
Program for Nitrogen Control guidelines.
I

'rOJCCC Numt;er,. Map Title:
12029.P I Fitjure I - 2010 U5G51
Topotyaphic Map
8 103 Dreamy Way
Ralei4jh
Wake County, NC
Soil & Environmental Consultants, PA
i101O Rmn Ndge Rd.- ReWgh, NC 27614
(912) 846459M - (919) W9487
Web Page! www SwEexam

'rOJCCC Numver: Map Totle.,
I 2029.P I j fir-pre 2 - NRC5 5011
Soil & Environmental Consultants, PA
IMO Rom Ridge Rd.- Rdeigh, NC 27614
(98) 846-5W ® (919) W9467
Web Pop: www SWEC.ccm

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Project: 8103 DREAMY WAY Project No.: J 2029*.D 1
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-ocation:WAKE CO., NC . Mcjr.0
Client: H.J. MORP\15
CON5TRUCTION, INC.
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Step 1 Determine area for each type of land use and enter in in Column (2).
Step 2 Total the areas for each type of land use and enter at the bottom of Column (2).
Step 3 Multiply the areas in Column (2) by the TN export coefficients in Column (3) and enter in Column (4).
Step 4 Total the TN exports for each type of land use and enter at the bottom of Column (4).
Step 5 Determine the export coefficient by dividing the total TN export from uses at the
bottom of Column (4) by the total area at the bottom of Column (2).
(1) (3) (4)
Type of Area TN Export TN Export
Land Cover (acres) Coeff. from Use
Peranently Protected Undisturbed i
r i .
Permanently Protected Managed I 0.25 I 1.20 I 0.30
Open Space (grass, landscaping, etc.)
Impervious Surfaces (roads, parking, 0.00 21.20 0.00
lots, driveways, roofs, paved storage
areas, etc.)
TOTAL 0.25 0.30
Total Nitrogen Export Coefficient
NOTE: If TN export rate is greater than 6.0 lbs. /ac. /yr. then a BMP must be installed
to remove enough Nitrogen to bring the TN export rate below 3.6 lbs. /ac. /yr.
PROPOSED CONDITIONS
Based on Proposed Site Uses
(1)
Type of
Land Cover
(2)
Area
(acres)
(3)
TN Export
Coeff.
lbs. /ac./ r.
(4)
TN Export
from Use
lbs./ r.
Peranently Protected Undisturbed
Open Space (forest, unmown meadow)
0.00
0.60
0.00
(Assume No Penn. Protect. Undisturbed Open Space)
Permanently Protected Managed
Open Spa (grass, landscaping, etc.)
0.16
1.20
0.19
(Assume All Non - imperv. Areas to be Managed Open Space)
Impervious Surfaces (roads, parking,
lots, driveways, roofs, paved storage
areas, etc.)
0.09
21.20
1.86
TOTAL 0.25 2.06
Total Nitrogen Export Coefficient = 1 8.23 lbs. /ac. /yr.
NOTE: For Residentail Development if TN export rate is greater than 6.0 lbs./ac./yr. then a BMP must be installed
to remove enough Nitrogen to bring the TN export rate below 3.6 lbs./ac./yr.
Nitrogen Export Rate Evaluation:
If the computed TN export rate for the post - development site is greater than 6.0 lbs. /ac. /yr. then the Owner must use on -site BMP's to bring
the development's export down to 6.0 lbs. /ac. /yr. Then the Owner may utilize one of the following options;
1.) Supplemental BMP's to reduce the TN export rate down to 3.6 lbs. /ac. /yr.
2.) Pay a one -time offset payment of $330 /lb. to bring the rate down to 3.6 lbs. /ac. /yr.
3.) Do a combination of BMP's and offset payment to bring the rate down to 3.6 lbs. /ac.lyr.
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Forrest Creek Riparian Buffer Mitigation Bank
Rudolph Riparian Buffer Bank
Statement of Availability April 22, 2013
NC Division of Water Quality U.S. Army Corps of Engineers
Ms. Katie Merritt Mr. Monti Matthews
1650 Mail Service Center
Raleigh, NC 27699-1650
CESAW-RG-R
Raleigh Regulatory Field Office
3331 Heritage Trade Center., Suite 105
Wake Forest, NC 27587
Best Regards
InAdL
Matthew R. Fisher
EBX-EM, LLC
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