20010095 Ver 1_Complete file_19991208

State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Bill Holman, Secretary
Kerr T. Stevens, Director
11kq1WAj
/ • •
A;jA
A90 1k
NCDENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
December 8, 1999
Wake County
Trinity Associates, LLC
C/o Mr. Thomas M. Rahill
7225 Airlie Place Road
Wilmington, NC 28403
RE: Trinity Road Variance
Dear Mr. Rahill,
On November 5, 1999 the Division of Water Quality (DWQ) was notified by receipt of the Hydrology &
Hydraulic Addendum report prepared by Rice & Associates and dated November 3, 1999 for use in a request
for a variance from the Neuse River Basin: Nutrient Sensitive Waters Management Strategy: Protection and
Maintenance of Riparian Areas with Existing Forest Vegetation (15A NCAC 2B .0233). The DWQ has the
following comments as related to your proposed plan.
1. Stormwater
A. The proposed plan (including information provided within the 10/27/99 plan) does not provide
adequate information to show that the proposed stormwater treatment would remove 85% TSS.
Please provide additional information as to how the proposed BMP will remove 85% TSS.
B. In order to be in harmony with the general purpose and intent of the buffer requirements the
maximum allowable nitrogen export for a commercial or industrial development is 10
pounds/acre/year, if offset payments are made to meet the nitrogen export standard of 3.6
pound/acre/year. The treated 30-acre drainage area is predicted as having an export rate of 10.8
pounds/acre/year. The combined untreated 12-acre and treated 18-acre drainage area is predicted as
having an export rate of 8.9 pounds/acre/year. It seems highly unlikely that the plan providing
complete treatment would have a higher export rate than the plan providing only partial treatment. It
appears that the "uptake percentage" was calculated incorrectly. The previous calculations accounted
for "level spreaders, detention ponds and riparian buffers". The new calculations do not include the
"riparian buffers". Please provide information as to why the "riparian buffers" were included in the
first calculations and not the new calculations. The DWQ recommends that stormwater from the
entire (30-acre) watershed be treated. The proposed plan should therefore include additional BMP's
to bring the export rate at least below 10 pounds/acre/year. The proposed plan should also make
offset payments to meet the export standard of 3.6 pounds/acre/year as described within 15A NCAC
2B .0240 (i.e., $11/pound/year sufficient to fund off setting nitrogen reduction measures for 30
years).
C. The proposed by-pass of the off site, untreated stormwater from the upper end of the watershed (i.e.,
the Starmount Site) around the treatment area and directly into Richlands Creek, without providing
diffuse flow prior to entering the buffers, does not follow the general purpose and intent of the buffer
requirements. If the entire (30-acre) drainage area is treated, then this would no longer become an
issue. If this area is not treated, DWQ staff will oppose this variance.
Non-Discharge Branch Wetlands/401 Unit 1621 Mail Service Center Raleigh North Carolina 27669-1621
Telephone [phone] FAX # [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/ 10% post consumer paper
2. Buffer Mitigation
The proposed plan does not offer any buffer mitigation as pursuant to 15A NCAC 2B .0242 for the
loss of existing riparian buffers. Please provide additional information describing how the proposed
plan will fulfill this mitigation.
3. General Comments
A. DWQ staff believes that the proposed berm along Richland Creek would essentially cut the stream off
from its floodplain. Possibly, resulting in stream instability and bank erosion. The proposed plan
does not provide any information in respect to this issue. Please provide the DWQ with additional
information addressing this concern.
B. Please provide documentation as to when this tract was last subdivided. DWQ staff has concerns
that, due to previously obtained knowledge, this tract was subdivided after the effective date of the
rules. If this is the case then DWQ staff believes that the practical difficulties and unnecessary
hardships were willingly brought upon the applicant. For this reason, the DWQ may not be able to
support the variance request. Please provide the DWQ with additional information regarding this
issue.
The DWQ will oppose the variance request unless the comments listed above are thoroughly addressed and
abate staff concerns.
Please call Bob Zarzecki at 919-733-9726 if you have any questions or require copies of our rules or
procedural materials.
Cc:
Mr. Steve
Central Files
Bob Zarzecki, DWQ 401 Certification Unit

P. 01
f J TRANSACTION REPORT
JAN-06-2000 THU 02:59 PM

?c DATE START RECEIVER TX TIME PAGES TYPE NOTE M# DP

JAN-06 02:58 PM 94628707 1'26" 2 SEND OK 135

TOTAL 1M 26S PAGES: 2

State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James S. Hunt, Jr., Governor
Bill Holman, Secretary
Kerr T. Stevens, Director
maim-
NCDENR
NORTH CAROLINA DXPARTMeNT OF
ENVIRONMENT ANO NATURAL RE.souRCEs
December 8. 1999
Wake County
Trinity Associates, UC
Go Mr. Thomas M. Rahill
7225 Airlie Place Road
Wilmington, NC 28403
RE: Trinity Road Variance
Post-W Fax Note 7671 Date 6 0o Peg°E"? Z
To T ^.f l?Ld From z?
CoMept. i Co.
Phone # Phone 0
733^ Wz&
Fax # 1?/Z' r??O7 Fax #
Dear Mr. Rahill,
On November 5, 1999 the Division of Water Quality (DWQ) was notified by receipt of the Hydrology &
Hydraulic Addendum report prepared by Rice & Associates and dated November 3. 1999 for use in a request
fora variance from the Neuse River Basin: Nutrient Sensitive Waters Management Strategy: Protection and
Maintenance of Riparian Areas with Existing Forest Vegetation (15A NCAC 2B.0233). The DWQ has the
following comments as related to your proposed plan.
State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Bill Holman, Secretary
Kerr T. Stevens, Director
NCDENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
December 8, 1999
Wake County
Trinity Associates, LLC
C/o Mr. Thomas M. RahiIl
7225 Airlie Place Road
Wilmington, NC 28403
RE: Trinity Road Variance
Dear Mr. Rahill,
Post-it® Fax Note 7671 Date !?(o?UU pages
To X-To C : d From 'ew Z RZIzZ K
Co./Dept. . /Gc? / r3fo[ , Co. QG??
Phone # Phone # 733- Wz&
Fax # LOZ Fax #
On November 5, 1999 the Division of Water Quality (DWQ) was notified by receipt of the Hydrology &
Hydraulic Addendum report prepared by Rice & Associates and dated November 3, 1999 for use in a request
for a variance from the Neuse River Basin: Nutrient Sensitive Waters Management Strategy: Protection and
Maintenance of Riparian Areas with Existing Forest Vegetation (15A NCAC 2B .0233). The DWQ has the
following comments as related to your proposed plan. -
1. Stormwater
A. The proposed plan (including information provided within the 10/27/99 plan) does not provide
adequate information to show that the proposed stormwater treatment would remove 85% TSS.
Please provide additional information as to how the proposed BMP will remove 85% TSS.
B. In order to be in harmony with the general purpose and intent of the buffer requirements the
maximum allowable nitrogen export for a commercial or industrial development is 10
pound//acre/year, if offset payments are made to meet the nitrogen export standard of 3.6
pound/acre/year. The treated 30-acre drainage area is predicted as having an export rate of 10.8
pound//acre/year. The combined untreated 12-acre and treated 18-acre drainage area is predicted as
having an export rate of 8.9 pounds/acre/year. It seems highly unlikely that the plan providing
complete treatment would have a higher export rate than the plan providing only partial treatment. It
appears that the "uptake percentage" was calculated incorrectly. The previous calculations accounted
for "level spreaders, detention ponds and riparian buffers". The new calculations do not include the
"riparian buffers". Please provide information as to why the "riparian buffers" were included in the
first calculations and not the new calculations. The DWQ recommends that stormwater from the
entire (30-acre) watershed be treated. The proposed plan should therefore include additional BMP's
to bring the export rate at least below 10 pound//acrelyear. The proposed plan should also make
offset payments to meet the export standard of 3.6 pound//acre/year as described within 15A NCAC
2B .0240 (i.e., $11/pound/year sufficient to fund off setting nitrogen reduction measures for 30
years).
C. The proposed by-pass of the off site, untreated stormwater from the upper end of the watershed (i.e.,
the Starmount Site) around the treatment area and directly into Richlands Creek, without providing
diffuse flow prior to entering the buffers, does not follow the general purpose and intent of the buffer
requirements. If the entire (30-acre) drainage area is treated, then this would no longer become an
issue. If this area is not treated, DWQ staff will oppose this variance.
Non-Discharge Branch Wedands/401 Unit 1621 Mail Service Center Raleigh, North Carolina 27669-1621
Telephone [phone] FAX # [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/10% post consumer paper
A. DWQ staff believes that the proposed berm along Richland Creek would essentially cut the stream off
from its floodplain. Possibly, resulting in stream instability and bank erosion. The proposed plan
does not provide any information in respect to this issue. Please provide the DWQ with additional
information addressing this concern.
B. Please provide documentation as to when this tract was last subdivided. DWQ staff has concerns
that, due to previously obtained knowledge, this tract was subdivided after the effective date of the
rules. If this is the case then DWQ staff believes that the practical difficulties and unnecessary
hardships were willingly brought upon the applicant. For this reason, the DWQ may not be able to
supportthe variance request. Please provide the DWQ with additional information regarding this
issue.
The DWQ will oppose the variance request unless the comments listed above are thoroughly addressed and
abate staff concerns. -
Please call Bob Zarzecki at 919-733-9725 if you have any questions or require copies of our rules or
procedural materials.
Cc:
Mr. Steve
Central Files
Bob Zarzecki, DWQ 401 Certification Unit
State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Bill Holman, Secretary
Kerr T. Stevens, Director
1 ? •
NC ENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
December 3, 1999
Wake County
U`
Trinity Associates, LLC ,J 4
C/o Mr. Thomas M. Rahill ZJ' JV
7225 Airlie Place Road , ?
V
ilmington, NC 28403
W
\\A)
RE: Trinity Road Variance
Dear Mr. Rahill,
On November 5, 1999 the Division of Water Quality (DWQ) was notified by receipt of the Hydrology &
Hydraulic Addendum report prepared by Rice & Associates and dated November 3, 1999 for use in a request
for a variance from the Neuse River Basin: Nutrient Sensitive Waters Management Strategy: Protection and
Maintenance of Riparian Areas with Existing Forest Vegetation (15A NCAC 2B .0233). The DWQ has the
following comments as related to your proposed plan.
1. Stormwater
A. The proposed plan (including information provided within the 10/27/99 plan) does not provide
adequate information to show that the proposed stormwater treatment would remove 85% TSS.
Please provide additional information as to how the proposed BMP will remove 85% TSS.
B. In order to be in harmony with the general purpose and intent of the buffer requirements the
maximum allowable nitrogen export for a commercial or industrial development is 10
pounds/acre/year, if offset payments are made to meet the nitrogen export standard of 3.6
pound/acre/year. The treated 30-acre drainage area is predicted as having an export rate of 10.8
pounds/acre/year. The combined untreated 12-acre and treated 18-acre drainage area is predicted as
having an export rate of 8.9 pounds/acre/year. It seems highly unlikely that the plan providing
complete treatment would have a higher export rate than the plan providing only partial treatment. It
appears that the "uptake percentage" was calculated incorrectly. The previous calculations accounted
for "level spreaders, detention ponds and riparian buffers". The new calculations do not include the
"riparian buffers". Please provide information as to why the "riparian buffers" were included in the
first calculations and not the new calculations. The DWQ recommends that stormwater from the
entire (30-acre) watershed be treated. The proposed plan should therefore include additional BMP's
to bring the export rate at least below 10 pounds/acre/year. The proposed plan should also make
offset payments to meet the export standard of 3.6 pounds/acre/year as described within 15A NCAC
2B .0240 (i.e., $11/pound/year sufficient to fund 0 years).
C. The proposed by-pass of the off site, untreated st r ears). from the upper end of the watershed (i.e.,
the Starmount Site) around the treatment area and directly into Richlands Creek, without providing
diffuse flow prior to entering the buffers, does no follow the general purpose and intent of the buffer
requirements. If the entire (30-acre) drainage ar is treated, then this would no longer become an
issue. [sue IS blQ <
Non-Discharge Branch Wetlands/401 Unit 1621 Mail Service Center Raleigh, North Carolina 27669-1621
Telephone [phone] FAX # [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/10% post consumer paper
2. Buffer Mitigation
The proposed plan does not offer any buffer mitigation as pursuant to 15A NCAC 2B .0242 for the
loss of existing riparian buffers. Please provide additional information describing how the proposed
plan will fulfill this mitigation.
3. General Comments
A. DWQ staff believes that the proposed berm along Richland Creek would essentially cut the stream off
from its floodplain?Assibly, resulting in stream instability and bank erosion. The proposed plan
does not provide any information in respect to this issue. Please provide the DWQ with additional
information addressing this concern.
B. Please provide documentation as to when this tract was last subdivided. DWQ staff has concern/
that, due to previously obtained knowledge, this tract was subdivided after the effective date 0-the
rules. If this is the case then DWQ staff believes that the practical difficulties and unnecessary
hardships were willingly brought upon the applicant. For this reason, the DWQ ' not/support the
variance request. Please provide the DWQ with additional information regarding this issue.
The DWQ will rt the variance request unless the comments listed above are thoi ughly addressed
and abate staff concerns. Me-
I
Please call Bob Zarzecki at 919-733-9726 if you have any questions or require copies of our rules or
procedural materials.
Sincerely,
John R. Dorney
c?

Cc: Mr. Steve Mitchell, Raleigh Regional Office
Central Files
Bob Zarzecki, DWQ 401 Certification Unit

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State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Bill Holman, Secretary
Kerr T. Stevens, Director
1
NC ENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
November 9, 1999
a
MEMO f
TO: Steve Mitchell, Raleigh Regional Office
odd -St. ? b`
1 u, Water Quality Planning
FROM: John Dor
RE: Preliminary Review - Neuse Buffer Rule Variance - Trinity Road Project
Please review the attached report and accompanying map dated October 27, 1999
from Steve Rice and Associates. They propose to culvert the intermittent stream, which
is parallel to Trinity Road and up slope of Edward's Mill Road. In return, they propose to
construct a stormwater management system in the floodplain of Richland Creek which
would treat runoff from a 20 acre waterbed - most of which does not receive treatment
now.
The uppermost 9.7 acre tract would be bypassed since the allege that its treatment
would be impractical. I have asked them to supply additional information in this regard,
but stated that I would prefer treatment of this area as well, if possible.
Please review these plans and submit written comments to Bob Zarzecki by
November 22, 1999. If you would like a site visit or meeting, please call Bob at 733-
1786 to arrange them.
Cc: Bob Zarzecki
Steve Rice, Steve Rice and Associates
Wetlands/401 Unit 4401 Reedy Creek Road Raleigh, North Carolina 27607
Telephone [phone] FAX # [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/10% post consumer paper
State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Bill Holman, Secretary
Kerr T. Stevens, Director
1 11kTT1F'J •
"Now
AIM 111
NCDENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
November 9, 1999
MEMO
TO: Steve Mitchell, Raleigh Regional Office
Todd St. John
Lin Xu, Water Quality Planning
FROM: John Do
RE: Preliminary Review - Neuse Buffer Rule Variance - Trinity Road Project
Please review the attached report and accompanying map dated October 27, 1999
from Steve Rice and Associates. They propose to culvert the intermittent stream, which
is parallel to Trinity Road and up slope of Edward's Mill Road. In return, they propose to
construct a stormwater management system in the floodplain of Richland Creek which
would treat runoff from a 20 acre waterbed - most of which does not receive treatment
now.
The uppermost 9.7 acre tract would be bypassed since the allege that its treatment
would be impractical. I have asked them to supply additional information in this regard,
but stated that I would prefer treatment of this area as well, if possible. _
Please review these plans and submit written comments to Bob Zarzecki by
November 22, 1999. If you would like a site visit or meeting, please call Bob at 733-
1786 to arrange them.
Cc: Bob Zarzecki
Steve Rice, Steve Rice and Associates
Wetlands/401 Unit 4401 Reedy Creek Road Raleigh, North Carolina 27607
Telephone [phone] FAX # [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/10% post consumer paper
Trinity Road Variance
Subject: Trinity Road Variance
Date: Mon, 29 Nov 1999 11:29:41 -0500
From: Steve Mitchell <[e-mail]>
To: Bob Zarzecki <Bob.Zarzecki @ncmail.net>
NO WAY ! ! ! ! ! ! We already let them get by with hammering the buffer along Trinity Road at the edge of
this site. The stream becomes subject just about mid way up the feature. The up stream (u s & d s ) guys
did not have to do any stormwater (s w) control because they were over 100 feet away from the point. The
idea of putting a gas station overtop of the creek sucks. The knew this site was subject from the
development that went on all around this place and now the want to use the Richland creek end of it to
treat s w. I think not. I would recommend not supporting this one
1 of 1 11/29/99 3:44 PM
Trinity Road Project - Neuse Variance
s
Subject: Trinity Road Project - Neuse Variance
Date: Wed, 24 Nov 1999 14:00:11 -0500
From: Bob Zarzecki <[e-mail]>
To: "Steven R. Mitchell" <[e-mail]>
Just checking to see if you've had a chance to review the Trinity Road
variance request from Trinity Associates, LLC and Steve Rice. I need to
reply to their November 3rd response and would like to have your
response for inclusion within my letter. Thanks.
1 of 1 11/24/99 2:00 PM

State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Bill Holman, Secretary
Kerr T. Stevens, Director
A 4 • • W'A
NC ENR
Nam
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
November 9, 1999
MEMO
TO:
FROM:
RE:
Steve Mitchell, Raleigh Regional Office
Todd St. John
Lin Xu, Water Quality Planning
John Do 4?)

Preliminary Review - Neuse Buffer Rule Variance - Trinity Road Project
Please review the attached report and accompanying map dated October 27, 1999
from Steve Rice and Associates. They propose to culvert the intermittent stream, which
is parallel to Trinity Road and up slope of Edward's Mill Road. In return, they propose to
construct a stormwater management system in the floodplain of Richland Creek which
would treat runoff from a 20 acre waterbed - most of which does not receive treatment
->+"
now.
The uppermost 9.7 acre tract would be bypassed since he liege that its treatment
would be impractical. I have asked them to supply additional information in this regard,
but stated that I would prefer treatment of this area as well, if possible.
Please review these plans and submit written comments to Bob Zarzecki by
November 22, 1999. If you would like a site visit or meeting, please call Bob at 733-
1786 to arrange them.
Cc: Bob Zarzecki
Steve Rice, Steve Rice and Associates
N
Wetlands/401 Unit 4401 Reedy Creek Road Raleigh, North Carolina 27607
Telephone [phone] FAX # [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/10% post consumer paper
? ?60 v
I
Y
? L
00
I&? LETTE
RICE &
ASSOCIATES
T MR. TODD ST. N
ivis ?ater Quality
NCDENR
4211 Reedy Creek Road
Raleigh, NC
DATE: NOVEMBER 5, 1999.
RE: TRINTY ROAD TREATMENT AREA
RALEIGH, NC
PN: 99.086
SENDING: ® Attached ? Under Separate Cover ? Via US Mail ? Overnight UPS/FedEx ® Messenger ? To Be Picked Up By Recipient
* Three (3) copies of addendum to report investigating the treatment of the entire 30-acre watershed
COMMENTS:
* To aid in review of the submitted treatment area proposal
COPY TO: TOM RAHILL, BLUE RIDGE LAND CO.
MR • Taptg V*040SY . A.W-J>E,0VR
TRANSMITTAL
SENT BY: y ( 'J L-
Tedd Cyr tedle i
116 New Edition Court 9 Cary, North Carolina 27511 9 Voice 919.462.8474 • Fax [phone] • Email: [e-mail]
IQi LETTER OF
1\1\.L M
ASSOCIATES
TRANSMITTAL
TO: MR. TODD ST. JOHN DATE: NOVEMBER 5, 1999
Division of Water Quality
NCDENR RE: TRINTY ROAD TREATMENT AREA
4211 Reedy Creek Road RALEIGH, NC
Raleigh, NC
PN: 99.086
SENDING: ® Attached ? Under Separate Cover ? Via US Mail ? Overnight UPS/FedEx ® Messenger ? To Be Picked Up By Recipient
* Three (3) copies of addendum to report investigating the treatment of the entire 30-acre watershed
il rle?lko
..
?:"
COMMENTS:
* To aid in review of the submitted treatment area proposal
COPY TO: TOM RAHILL, BLUE RIDGE LAND CO.
SENT BY: dr=A L J
Ted Credle
116 New Edition Court • Cary, North Carolina 27511 • Voice 919.462.8474 • Fax [phone] • Email: [e-mail]
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Site Plan 17!14/2000
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Richland Creek Restoration - P.O.# 200010040 I. Boling
FIGURE NO.
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TRACT 1, LOT 1
2.023 ACRE PARCEL
TRINITY ROAD & EDWARDS MILL ROAD
RALEIGH, NORTH CAROLINA
HYDROLOGY & HYDRAULIC CALCULATIONS
prepared for.
TRINITY ASSOCIATES, LLC
Contact: Mr. Thomas M. Rahill
7225 Airlie Place Road
Wilmington, North Carolina 28403
910-256-9918
prepared by:
I&A
RICE &
ASSOCIATES
116 New Edition Court
Cary, North Carolina 27511
Voice: 919.462.8474
Fax: [phone]
October 27, 1999

TRACT 1, LOT 1
2.023 ACRE PARCEL
TRINITY ROAD & EDWARDS MILL ROAD
RALEIGH, NORTH CAROLINA
HYDROLOGY & HYDRAULIC CALCULATIONS
prepared for
TRINITY ASSOCIATES, LLC
Contact: Mr. Thomas M. Rahill
7225 Arlie Place Road
Wilmington, North Carolina 28403
910-256-9918
prepared by:
I 'I - ,
I &a
RICE &
ASSOCIATES
116 New Edition Court
Cary, North Carolina 27511
Voice: 919.462.8474
Fax: [phone]
October 27, 1999
' TABLE OF CONTENTS
1
' • Objective
• Hydraulics
' • Methodology
' . Site Treatment
' • Results Summary
• Hydrographs

1
OBJECTIVE
The owner of Tract 1, Lot 1, Trinity Associates, LLC, proposes to fill and/or grade the entire lot
to allow for the development of the land. The subject lot is approximately 450 feet long
(Trinity Road frontage) by 185 feet wide (Edwards Mill Road Extension) and is approximately
2.023 acres in area. Approximately one half of the lot is encumbered by a Neuse River Basin
Buffer as identified by Soils and Environmental Consultants, Inc. and confirmed by the Water
' Quality Division of NCDHNR. The drainage way within the buffer accepts approximately 20
acres of upstream or offsite storm water runoff.
' In order to use or develop the lot it will be necessary fill and/or disturb all of the buffer area in
its entirety. Trinity Associates understands that in order to proceed with this plan it will be
' necessary to obtain a variance from the Environmental Management Commission. They
further understand that to obtain the variance they will be required to provide mitigation in the
form of storm water detention and constructed wetlands or some alternative method of
' providing sediment and nutrient removal from storm water off the site and/or upstream or
adjacent sites.
' The developer, at one time, owned the tract of land on the east side of Edwards Mill Road
Extension, Trinity Associates, LLC, Tract 5, that is approximately 4.5 acres in size. This tract is
bordered on the east by Richland Creek and on the north by Trinity Road and is currently
under preliminary subdivision and site plan review by the City of Raleigh for a convenience
store. Also, Neuse River Basin Buffers, City of Raleigh Greenways, and 100-year floodway
encumbers a large portion of Tract 5. Commercial development of the buffers, greenways
and floodway is not allowed, nor is it proposed, but the previous owner, Trinity Associates,
reserved the right to utilize all or portions of the buffer, greenway, and the unfilled portions of
' flood plains for storm water detention if it was required or imposed on the other tracts within
the Trinity Associates property.
' The developer proposes to fill/develop the subject 2-acre lot. As mitigation, the developer
proposes to provide storm water detention and nutrient removal for the site to be filled, plus
10 acres of upstream or adjacent property, and the storm water runoff from the downstream
4.5-acre tract on the east side of Edwards Mill Road Extension. The subject drainage areas
and the proposed treatment area are delineated on attached graphic exhibits.
' The following hydrology and hydraulic calculations illustrate physically and quantitatively how
that-will be accomplished by collecting and treating onsite and offsite storm water through the
use of storm water detention and nutrient removal utilizing existing and proposed trees..
See attached exhibit for an overall view of the area and the proposed project.

1

GENERAL DESIGN INFORMATION
' • The total drainage area to be treated is 17.9 acres. The drainage area consists of the
2.0 acre site to be filled, upstream developed area of 4.6 acres, upstream public street
' right-of-way of 0.2 acres, adjacent developed area of 5.2 acres, public street right-of-
way of 1.5 acres, and down stream developed area of 4.4 acres.
' • The lot that is proposed to be filled constitutes approximately 12.3 % of the total
drainage area.
' • Storm water detention will be provided to detain peak storm water runoff from all of the
identified drainage areas for the 100-year storm. The detained volume will be drained
over a period of less than two days.
• Vegetation will be used to accomplish nutrient uptake in the area provided (see C-0).
' • Nutrient loading is provided by the NCDENR model: "Neuse River Basin: Model
Stormwater Program for Nitrogen Control", as provided by NCDENR (see attached
sheets for documentation).
• Uptake numbers were provided by NCDENR (see attached sheets for documentation).
HYDRAULICS
' To model the drainage areas the HYdraflowTM "HYdro9raPhs for Windows" by Intelisolve
software package was used. This software creates inflow hydrographs (SCS/TR-55 Method)
' based on drainage basin characteristics input by the user. The user modeled the 2-year, the
5-year, the 10-year, the 25-year, the 50-year and the 100-year storm. The resulting
hydrographs were plotted.
' METHODOLOGY
The drainage area was modeled as a developed site using HydraflovVm "Hydrographs for
Windows". The site was then analyzed as if the 2-year, the 5-year, the 10-year, the 25-year,
the 50-year and the 100-year hydrologic event had taken place. The peak runoffs were then
plotted.
' Off site drainage from the upper end of the watershed (hereafter referred to as the "Starmount
Site") was bypassed around the treatment area and introduced directly into the Stream.
1

r

STORM WATER TREATMENT AND NUTRIENT REMOVAL
• The developer proposes to provide a treatment area from bounded by Trinity Road,
Richland Creek, Edwards Mill Road Extension, and the drive entrance to the Raleigh
School, or approximately 2.0 acres.
• To temporarily contain the storm water for detention and treatment the developer
proposes to construct an earthen berm parallel to Richland Creek to serve as a dam.
Incorporated into the dam will be a walking path on top of the berm. Storm water will
be slowly released into Richland Creek through a series of small diameter pipes under
the berm over a period of less that two days.
• The toe of the walking path berm will be located 5 feet off the stream bank and
parallel to the stream bank throughout the site. The paved portion of the walking path
will be 7 feet wide and will be constructed 30" above the existing grade with 2:1 side
slopes stabilized with appropriate ground cover. The breadth of the total pathway will
be 12 feet.
• Storm water will be introduced into the treatment area by way of a series of settling
ponds and riprap filters in such a way as to introduce "sheet flow" across to treatment
area for nutrient uptake by existing and proposed trees. The density of trees will be
equal to or greater than ? trees per acre.
Nitrogen compounds are found in a variety of forms in surface water. Some of the
compounds are not dissolved but rather adsorbed onto particulate matter. The
"tortuous path" provided by vegetation in the treatment area allows settling to occur
(85% TSS removal), thereby reducing the nitrogen load into the receiving body of
water. Settling the particulate matter has the added effect of removing metals and
non-soluble pollutants as well.
• The length of the flow path and the settling time provided by the treatment area will
have the added benefit of increasing infiltration. The filtering action of soil and plants,
and biological activities in the soil, take up a variety of nutrients as stormwater moves:
through the treatment area.
' For dissolved nutrients, vegetation in the treatment area will be the focal point of
reducing inputs to surface water. The existing and proposed trees provide longer
contact times with pollutants, aid in the settling of particles that have pollutants
' adsorbed on them, and greatly increase biological uptake as they consume dissolved
nutrients through the water.
L'?

RESULTS SUMMARY
• Developed peak run-off for 10-year event without storm water treatment = 111.7 CFS
• Developed peak run-off for 100-year event without storm water treatment = 152.2 CFS
• Developed peak run-off for the 10-year event routed through the area = 37.6 CFS
• Developed peak run-off for the 100-year event routed through the area = 83.5 CFS
• Time to bleed down 10-year peak storage = 1.66 days
• Time to bleed down 100-year peak storage = 1.75 days
• Nutrient Loading from 2-acre site without treatment = 11.9 TN Ibs/acre/ year
• Nutrient Loading from 2-acre site with treatment = 5.0 TN Ibs/acre/year
• Nutrient Loading from 18-acre drainage area without treatment= 16.5 TN Ibs/acre/ year
• Nutrient Loading from 18-acre drainage area with treatment = 6.9 TN Ibs/acre/year

27 -Combine- lOYr - Qp = 111.68 cfs
150
100 In
Q
50 In
0 Out
0 5 10 15 20 25
Time (Hrs)
10-YEAR EVENT - PROPOSED CONDITIONS
OUTFLOW HYDROGRAPH

Q
150
1 00
'50
0
0
33 - Reservoir -10 Yr - Qp = 37.64 cfs
in
/ out
10-YEAR EVENT - ROUTED
OUTFLOW HYDROGRAPH
10 15 20 25 '30
Time. (Hrs)

3%3 - Reservoir -1 In :''r - Ma El. = 7*1.? f+
73.0
;
1 # t I I I
# # # i J I
# i i #
72.4 ' ( #
# ! # I I i
# i I I
i I 't I I f
71.8 i I # i # I E
Elev (4)
71.2i
70.6 j... --- --}--._ .. _ - .... - ---f - -
J
l ( ? I I
i t
70.0
0
5 10 15
Time (Hrs)
110
20 25 -1
10-YEAR EVENT - TIME-ELEVATION CURVE

'I 30 - Combine -100 Yr - Qp = 169.74 cfs
i '
200-
150- In
Q 100
In
50
Out
0
0 5 10 15 20 25
Time (Hrs)
100-YEAR EVENT PROPOSED CONDITIONS
OUTFLOW HYDROGRAPH

36 - Reservoir -100 Yr - Qp = 130.22 cfs
200
150
In
Q 100
50
Out
00 5 10 15 20 25 30
Time "s)
100-YEAR EVENT - ROUTED
OUTFLOW HYDROGRAPH

36 - Reservoir -100 Yr - Max. El. = 72.6 ft
73.0
72.4
71.8
Elev (ft)
71.2-
70.6-
70.0
Time (Hrs)
100-YEAR EVENT - TIME-ELEVATION CURVE
0 5 10 15 20 25 30

I HYDRAULIC CALCULATIONS
' Design Requirements & Calculations
' The delineated drainage area totals 17.9 acres. It is assumed this area will be developed as
office space. For the 10-year storm this yielded an input flow of 111 cfs.
' The treatment area was delineated and contains 2.3 acres of surface area. The depth over
the treatment area is 2.5'.
' The storage area has a volume of 123,000 cubic feet.
The walkway will act as emergency spillway for flows greater than the 100-year storm.
' Outlet drains are placed under the walkway to allow the treatment area to drain. The pipes
are sized as 6" pipes. The area will drain in 1.66 days (see attached spreadsheet).
' Nutrient Loading
From the "Neuse River Basin: Model Stormwater Program for Nitrogen Control", the loading
for this drainage area and the uptake for this treatment area were computed (see attached
' worksheets).
D

ll

'•s i :: wrui. i •.•.,apgO • ................ - -
iH4S ••r, 7p..a.•?ous+,?u? ?.??
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Q' 9.7-,?(G
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i
01NAl Of 309
a MNDEa' •. DRAINAGE AREA #l: 11.9 ACRES
wo.
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.• ?? .,L;,.. ?? . RELEASE PRINTS
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"" 7......... GRAPHIC SCALE
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MAn+EErtr.A
s? . • •' ( IN FEET )
1 inch = 200 ft.
RICHLAND CREEK
t......
:::.. ........ :........................ EXHIBIT

TRINITY ASSOCIATES, LLC
Treatment Area - 10 year Event
10/8/1999
Elevation Q Orifice
(ft above outlet, (ft^3/s)
2.00 5.3481
1.90 5.2127
1.80 5.0736
1.70 4.9307
1.60 4.7835
1.50 4.6316
1.40 4.4745
1.30 4.3118
1.20 4.1426
1.10 3.9662
1.00 3.7817
0.90 3.5876
0.80 3.3824
0.70 3.1640
0.60 2.9293
0.50 2.6740
0.40 2.3917
0.30 2.0713
0.20 1.6912
0.10 1.1959
0.00 0.0000
Sum outflow 73.7444
Pond Volume Time to Drain
(ft"3) (seconds)
45741.00 4276.39
45572.65 4371.33
45563.79 4490.24
45553.94 4619.42
45542.94 4760.44
45530.56 4915.23
45516.53 5086.18
45500.50 5276.32
45482.00 5489.53
45460.42 5730.91
45434.91 6007.25
45404.30 6327.94
45366.89 6706.26
45320.13 7161.90
45260.00 7725.48
45179.83 8447.84
45067.60 9421.51
44899.25 10838.39
44618.67 13191.31
44057.50 18420.70
42374.00 0.00
Orifice Constant = 0.6
Pipe diameter= 6
(in feet) 0.5
Number of Pipes = 10
Pond top surface area = 45741
(S.F.)
Pond Bottom surface area = 42374
(S.F.)
143264.57 Time (seconds)
1.66 Time (Days)

TRINITY ASSOCIATES, LLC
Treatment Area - 100 year Event
10/27/1999
Elevation Q Orifice Pond Volume Time to Drain
(ft above outle (ft^3/s) (ft" 3) (seconds)
2.50 5.9793 45741.00 3824.92 Orifice Constant = 0.6
2.40 5.8585 45606.32 3892.29
2.30 5.7352 45600.71 3975.52 Pipe diameter= 6
2.20 5.6091 45594.61 4064.33 (in feet) 0.5
2.10 5.4802 45587.95 4159.36 Number of Pipes= 10
2.00 5.3481 45580.67 4261.40 Pond top surface area = 45741'
1.90 5.2127 45572.65 4371.33 (S.F.)
1.80 5.0736 45563.79 4490.24
1.70 4.9307 45553.94 4619.42 Pond Bottom surface area = 42374
1.60 4.7835 45542.94 4760.44 (S.F.)
1.50 4.6316 45530.56 4915.23
1.40 4.4745 45516.53 5086.18
1.30 4.3118 45500.50 5276.32
1.20 4.1426 45482.00 5489.53
1.10 3.9662 45460.42 5730.91
1.00 3.7817 45434.91 6007.25
0.90 3.5876 45404.30 6327.94
0.80 3.3824 45366.89 6706.26
0.70 3.1640 45320.13 7161.90
0.60 2.9293 45260.00 7725.48
0.50 2.6740 45179.83 8447.84
0.40 2.3917 45067.60 9421.51.
0.30 2.0713 44899.25 10838.39
0.20 1.6912 44618.67 13191.31
0.10 1.1959 44057.50 18420.70
0.00 0 42374.00 0.00
151473.27 Time (seconds)
1.75 Time (Days)
Sue TEGT 51 TE
' Figure 2b: Method 2 for Ousntitying TN Export from Residential / Industrial / CornnM I
Developments when Footprints of all Impervious Surfaces are Shown
Step 1: Determine area for each type of land use and enter in Column (2).
' Step 2: Total the areas for each type of land use and enter at the bottom of Column (2).
Step 3: Muttiply 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 for site by dividing the total TN export from uses at the
bottom of Column (4) by the total area at the bottom of Column (2).

II
L

n

L
E

(1) .(2) (3) (4)
Type of Land Cover Area TN export coeff. TN export from use
(acres) (ibs/ac/yr)
Permanently protected undisturbed 0.6
'open space (forest, unmown meadow) O . 5 0.
3
Permanently protected managed 12
open space (grass, landscaping, etc.) O `? O • 5
Impervious surfaces (roads, parking 21.2
lots, driveways, roofs, paved storage 1 Z. 3.-
areas, etc.)
TOTAL Z O --- 2. 3 .
The rule requires that all new developments achieve a nitrogen export of less than or
equal to 3.6 pounds per acre per year. If the development contributes greater than 3.6
lbs/ac/yr of nitrogen, then the options shown in Table 2a are available based on whether
the dexelopment is residential or non-residential.
Table 2a- Witrnnnn FYnnrt RoAesetinn Antinne
Residential Commercial / Industrial
I. true computed export is less than 6.0 If the computed export is less than 10.0
tbs.- ac y.. then the owner may either: bs/ac/yr. then the owner may either:
1. install BMPs to remove enough nitrogen 1. install BMPs to remove enough nitrogen to
to bring the development down to 3.6 bring the development down to 16
Ibs/acyr. bWac yr. .
2. Pay a one-time offset payment of $330/!b 2. Pay a one-time offset payment of 5330/lb to
to bring the nitrogen down to the 3.6 bring the nitrogen down to the 3.6 bs/aclyr.
bs/ac/yr. 3. Do a combination of BMPs and offset
3. Do a combination of BMPs and offset payment to achieve a 3.6 l Wacyr export.
payment to achieve a 3.6 bs/a export.
If the computed export is greater than 6.0 If the computed exportis greater than 10.0
Wac/yr, then the owner must use on-site bslac%yr, then the owner must use on-site
BMPs to bring the development's export down BMPs to bring the. devebpriment's export down
to 6.0 ibs/actyr. Then, the owner may use one to 10.01bs/acyr. Then, the owner may use one
of the three options above to achieve the of the three options above to achieve the
reduction between 6.0 and 3.6 Wactyr. reduction between 10.0 and 3.6 IbWaclyr.
12

' RAIN A &E A g r=A
Figure 2b: Method 2 for Guantifying TN Export from Residential / Industrial / Commercial
Developments when Footprints of all impervious Surfaces are Shown
r"
Step 1: Determine area for each type of land use and enter 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 for site by dividing the total TN export from uses at the
bottom of Column (4) by the total area at the bottom of Column (2).

u
1

L

[1
1
(1) (2) (3) (4)
Type of Land Cover Area TN export coeff. TN export from use
(acres) (tbs/sclyr) (ID )
Permanently protected undisturbed 0.6
lopes, space (forest, unmown meadow) 2.0
1 . Z
Permanently protected managed 12
open space (grass, landscaping, etc.) 2-1
Z , S
Impervious surfaces (roads, parking 21,2
lots, driveways, roofs, paved storage
13
6
areas, etc.) . 2 9 2 ; (o
TOTAL j -7
The rule requires that all new developments achieve a nitrogen export of less than or
equal to 3.6 pounds per acre per year. If the development contributes greater than 3.6
lbs/ac/yr of nitrogen, then the options shown in Table 2a are available based on whether
the dexelopment is residential or non-residential.
Table 2a' Nitrnnan C,.nnrt OaA..nlmw? f%mf*.---
Residential Commercial / Industrial
I, tree computed export is less than 6.0 It the computed export is less than 10.0
bs. ac yr, then the owner may either: bs/ac/yr, then the owner may either-.
1. Install BMPs to remove enough nitrogen 1. Install BMPs to remove enough nitrogen to
to bring the development down to 3.6 bring the development down to 3.6
Ibs/ac/yr, NWactyr-
2. Pay a one-time offset payment of $330/lb 2. Pay a one-Pane offset payment of $330/lb to
to bring the nitrogen down to the 3.6 bring the nitrogen down to the 3.6 bs/ac/yr.
Ibs/ac/yr. 3. Do a combination of BMPs and offset
3. Do a combination of BMPs and offset payment to achieve a 3.6 bs wyr export.
payment to achieve a 3.6 bs/a export.
If the computed export is greater than 6.0 ff the computed export is greater than 10.0
Ibs,`aclyr. then the owner must use on-site bslaGyr, then the owner must use on-site
BMPs to bring the developments export down BMPs to bring the. devebprtmrs export down
to 6.0 lbs/ac/yr. Then, the owner may use one to 10.0 Ibs/ac/yr. Then, the owner may use one
of the three options above to achieve the of the three Options above to achieve the
reduction between 6.0 and 3.6 IlWactyr. reduction between 10.0 and 3.6 bma
yr.
12

Nutrient Uptake
From the guidelines presented on page 12 of "Neuse River Basin: Model Stormwater Program
for Nitrogen Control", the following calculations were done to show how uptake occurs within
the proposed treatment area.
SITE
Computed export: 11.9 TN lbs/acre/year
BMPs: outlet to act as a level spreader, bioretention, and use of the riparian
buffer
Uptake percentage: level spreader = 20%
bioretention = 25%
riparian buffer = 30%
Removal calculation: 11.9 - 20% = 9.5
9.5 - 25% = 7.1
7.1 - 30% = 5.0
Total loading of site: TN = 5.0 Ibs/acre/year
DRANAGE AREA
Similarly, the same calculations can be done for the entire drainage area:
Computed export: 16.5 TN Ibs/acre/year
BMPs: outlet to act as a level spreader, bioretention, and use of the riparian
buffer
Uptake percentage: level spreader = 20%
bioretention = 25%
riparian buffer = 30%
Removal calculation: 16.5 - 20% = 13.2-
13.2 - 25% = 9.9
9.9 - 30% = 6.9
Total loading of drainage area: TN = 6.9 Ibs/acre/year

t Table 2c: BMP Types, TN Removal Rates and Design Standards
TN
BMP Type Removal Rate
'
,P based on Current Appropriate Design Standards
' literature Studies
Wet detention ponds 25% NC and MD Des' n Manuals
Constructed wetlands 40% NC and MD Design Manuals
O n channel practices 30% NC and MD Design Manuals
Riparian buffers 30% Neuse Riparian Buffer Rule (15A NCAC 2B
Vegetated filler strips with 20? ?o •0233
levels reader NC and MD Design Manuals and other
' Bioreteraion literature information
25% NC and MD Design Manuals
Sand Filters 350% NC and MD Desi n Manuals
Pro rieta BMPs Varies Per manufacturer subject to DWQ roval
Otner BMPs Varies Sub'ect to DWQ a roval
7nnrc than one BMP is installed in series on a development, then the removal rate shall
be determined through serial rather than additive calculations. For example, if a wet
detention pond discharges through a riparian buffer, then the removal rate shall be
estimated to be 47.5 percent. (The pond removes 25 percent of the nitrogen and
' discharges 75 percent to the buffer. The buffer then removes 30 percent of the nitrogen
that discharged from the pond, which is 22.5 percent. The sum of 25 and 22.5 is 47.5.
The removal rate is NOT 25 percent plus 30 percent.)
' 2-F. BMP Maintenance
If BMPs are implemented to achieve the nitrogen loading and flow attenuation
' requirements for a development, then the local governments must require a maintenance
plan for the BMPs. The stormwater management plan must describe the local
government's selected approach for assuring BMP maintenance. Possible options to be
considered include, but are not limited to, the following:
' • The jurisdiction can charge a stormwater maintenance fee and assume the
responsibility of maintaining the stormwater BMP itself, including providing annual
inspection.
' • The jurisdiction can notify the owner upon finding that maintenance is needed on a
BINIP. If the owner does not complete the maintenance himself in a timely manner,
' then the jurisdiction can contract out the maintenance itself and recover costs in the
manner it determines most appropriate.
• The. jurisdiction can require that escrow accounts be set to provide resources to completely replace the BMP in the event of failure. sufficient
15

1
1
1
TRACT 1, LOT 1
2.023 ACRE PARCEL
TRINITY ROAD & EDWARDS MILL ROAD
RALEIGH, NORTH CAROLINA \
HYDROLOGY & HYDRAULIC ADDEND ui
prepared for.
TRINITY ASSOCIATES, LLC
Contact: Mr. Thomas M. Rahill
7225 Airlie Place Road
Wilmington, North Carolina 28403
910-256-9918
prepared by:
b f
LX. ?
RICE
ASSOCIATES
116 New Edition Court
Cary, North Carolina 27511
Voice: 919.462.8474
Fax: [phone]
November 3, 1999

ADDENDUM
' DESCRIPTION
Please find the attached hydrographs that show the results of routing the entire drainage area
' (including the 'Starmount' site) through the treatment area. These hydrographs show that in order to
achieve similar results as the proposed treatment area from a hydraulic perspective; the walkway
would need to be 5 feet above the bottom of the treatment area. This additional height requires
' additional fill slopes, resulting in a loss of approximately 5,400 square feet (9 feet of width by
approximately 600 feet of length) of usable treatment area. Although the reduced treatment area
would be more effective at sediment removal, the loss of trees apd vegetation will reduce the nutrient
' uptake capacity of the treatment area. 1*6 a? Fv,? y •,>wr c,11
Using the same number of drain pipes, the time to drain the deeper treatment area is increased to
2.70 days from the proposed 1.66 days. In order to drain the storm water runoff in under 2 days the
t number of pipes will have to be increased from 10 to 15, and the time to drain the treatment area is
1.80 days (see attached spreadsheet).
SUMMARY OF RESULTS
' 30-Acre Drainage Area Hydraulics
• Developed peak run-off for 10-year event without storm water treatment = 159.3 CFS
• Developed peak run-off for 100-year event without storm water treatment = 242.7 CFS
' • Developed peak run-off for the 10-year event routed through the area = 35.6 CFS
• Developed peak run-off for the 100-year event routed through the area = 123.4 CFS
' • Time to bleed down 10-year peak storage (additional pipes) = 1.72 days
• Time to bleed down 100-year peak storage (additional pipes) = 1.80 days
' Nutrient Loading_ 18 Acres Treated
• Nitrogen from 18-acres entering Richland Creek without treatment = 297 TN Ibs/ year
' • Nitrogen from 18-acres entering Richland Creek with treatment = 124 TN Ibs year
Nutrient Loading= 30 Acres Treated
' • Nitrogen from 30-acres entering Richland Creek without treatment = 421 TN Ibs/year ,ys1zLA"!
• Nitrogen from 30-acres entering Richland Creek with treatment = 321 lba&ear 0
Nutrient Loading - 18 Acres Treated & 12 Acres Untreated
lb'
• Nitrogen from 30-acres entering Richland Creek with treatment = 267 TN Ibs/year
Since nutrient loading from 30 acres treated is greater than the loading from 18 acres
' treated and 12 acres untreated, we propose that our initial plan be accepted without
modifications as presented in this addendum.

1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Nutrient Uptake
From the guidelines presented on page 12 of "Neuse River Basin: Model Stormwater Program
for Nitrogen Control", the following calculations were done to show how uptake occurs within
the proposed treatment area.
SITE
Computed export: 18.0 TN Ibs/acre/year
BMPs: outlet to act as a level spreader, bioretention, and use of the riparian
buffer
Uptake percentage: level spreader = 20%
detention pond = 25%
Removal calculation: 18.0 - 20% = 14.4
14.4 - 25% = 10.8

r- Total loading of site: TN = 10.8 Ibs/acre/year ?? 1V
For compliance, the TN level must be 3.6 Ibs/acre/year. Since the level is above 10
Ibs/acre/year the use of additional BMPs is mandated. This causes not only a financial
hardshi Iso is a practical impossibility, as there is no available land area to build another
BM_

21 - Combine -10 Yr - Qp = 159.29 cfs
200
150
In
Q 100
In
50
0' will' out
0 5 u 15 20, 25
Time (Hrs)

37 - Reservoir -10 Yr - Qp = 35.55 cfs
200
150
In
Q 100-
50
0 Out
0 5 10 15 20 25 30
Time (Hrs)

37 - Reservoir -10 Yr - Max. El. = 73.74 ft
74.0
73.2
72.4
Elev (ft)
71.6-
70.8-
70.01 0 5 10 15 20 25 30
Time (Hrs)

24-Combine -100Yr-Qp= 242.73cfs
250
200
In
150
Q.
100 In
50
Out
0
0 5 10 15 20 25
Time (Hrs)

38 - Reservoir -100 Yr - Qp = 123.4 cfs
250-
200-
150- In
Q
100-
50- / Out
0
0 5 10 15 20 25 30
Time (Hrs)

38 - Reservoir -100 Yr - Max. El. = 75.05 ft
76.0
74.8
73.6
Elev (ft)
72.4-
71.2-
70.0
0 5 10 15 20 25 30
Time (Hrs)

n
0

TRINITY ASSOCIATES, LLC
Treatment Area - 100 year Event
10/27/1999
Elevation Q Orifice Pond Volume Time to Drain
(ft above outlet) (ft^3/s) (ft^3) (seconds)
5.00 8.4561 45741.00 2704.62
4.90 8.3711 45673.66 2728.06
4.80 8.2852 45672.29 2756.25
4.70 8.1985 45670.85 2785.33
4.60 8.1108 45669.36 2815.35
4.50 8.0221 45667.80 2846.36
4.40 7.9325 45666.18 2878.42
4.30 7.8418 45664.48 2911.59
4.20 7.7501 45662.70 2945.94
4.10 7.6573 45660.83 2981.52
4.00 7.5633 45658.88 3018.43
3.90 7.4682 45656.83 3056.75
3.80 7.3718 45654.67 3096.56
3.70 7.2742 45652.39 3137.97
3.60 7.1752 45650.00 3181.09
3.50 7.0749 45647.47 3226.03
3.40 6.9731 45644.80 3272.94
3.30 6.8697 45641.97 3321.95
3.20 6.7649 45638.97 3373.24
3.10 6.6583 45635.78 3426.98
3.00 6.5500 45632.39 3483.36
2.90 6.4400 45628.77 3542.63
2.80 6.3279 45624.90 3605.03
2.70 6.2139 45620.75 3670.85
2.60 6.0978 45616.30 3740.41
2.50 5.9793 45611.50 3814.09
2.40 5.8585 45606.32 3892.29
2.30 5.7352 45600.71 3975.52
2.20 5.6091 45594.61 4064.33
2.10 5.4802 45587.95 4159.36
2.00 5.3481 45580.67 4261.40
1.90 5.2127 45572.65 4371.33
1.80 5.0736 45563.79 4490.24
1.70 4.9307 45553.94 4619.42
1.60 4.7835 45542.94 4760.44
1.50 4.6316 45530.56 4915.23
1.40 4.4745 45516.53 5086.18
1.30 4.3118 45500.50 5276.32
1.20 4.1426 45482.00 5489.53
1.10 3.9662 45460.42 5730.91
1.00 3.7817 45434.91 6007.25
Orifice Constant = 0.6
Pipe diameter= 6
(in feet) 0.
Number of Pipes 10
Pond top surface area = 45741
(S.F.)
Pond Bottom surface area = 42374
(S.F.)

0.90 3.5876 45404.30 6327.94
0.80 3.3824 45366.89 6706.26
0.70 3.1640 45320.13 7161.90
0.60 2.9293 45260.00 7725.48
0.50 2.6740 45179.83 8447.84
0.40 2.3917 45067.60 9421.51
0.30 2.0713 44899.25 10838.39
0.20 1.6912 44618.67 13191.31
0.10 1.1959 44057.50 18420.70
0.00 0 42374.00
233473.93 Time (seconds)
2.70 Time (Days)
I I

u

0

17
11?

TRINITY ASSOCIATES, LLC
Treatment Area -10 year Event
Elevation Q Orifice Pond Volume Time to Drain
(ft above outlet) (ft"3/s) (ft"3) (seconds)
4.20 7.7501 45741.00 1967.32
4.10 7.6573 45660.83 1987.68
4.00 7.5633 45658.88 2012.29
3.90 7.4682 45656.83 2037.83
3.80 7.3718 45654.67 2064.37
3.70 7.2742 45652.39 2091.98
3.60 7.1752 45650.00 2120.73
3.50 7.0749 45647.47 2150.69
3.40 6.9731 45644.80 2181.96
3.30 6.8697 45641.97 2214.64
3.20 6.7649 45638.97 2248.83
3.10 6.6583 45635.78 2284.65
3.00 6.5500 45632.39 2322.24
2.90 6.4400 45628.77 2361.75
2.80 6.3279 45624.90 2403.35
2.70 6.2139 45620.75 2447.23
2.60 6.0978 45616.30 2493.61
2.50 5.9793 45611.50 2542.73
2.40 5.8585 45606.32 2594.86
2.30 5.7352 45600.71 2650.35
2.20 5.6091 45594.61 2709.55
2.10 5.4802 45587.95 2772.91
2.00 5.3481 45580.67 2840.93
1.90 5.2127 45572.65 2914.22
1.80 5.0736 45563.79 2993.50
1.70 4.9307 45553.94 3079.62
1.60 4.7835 45542.94 3173.63
1.50 4.6316 45530.56 3276.82
1.40 4.4145 45516.53 3390.78
1.30 4.3118 45500.50 3517.54
1.20 4.1426 45482.00 3659.69
1.10 3.9662 45460.42 3820.60
1.00 3.7817 45434.91 4004.84
0.90 3.5876 45404.30 4218.62
0.80 3.3824 45366.89 4470.84
0.70 3.1640 45320.13 4774.60
0.60 2.9293 45260.00 5150.32
0.50 2.6740 45179.83 5631.90
0.40 2.3917 45067.60 6281.01
0.30 2.0713 44899.25 7225.59
0.20 1.6912 44618.67 8794.21
0.10 0 44057.50
Orifice Constant = 0.6
Pipe diameter= 6
(in feet) n r.
Number of Pipes 15
Pond top surface area = 41
(S.F.)
Pond Bottom surface area = 42374
(S.F.)
133880.82 Time (seconds)
1.55 Time (Days)

' TRINITY ASSOCIATES, LLC
Treatment Area - 100 year Event
10/27/1999
r
Elevation Q Orifice Pond Volume Time to Drain
' (ft above outlet) (ft^3/s) (ft^3) (seconds)
5.00 8.4561 45741.00 1803.08
4.90 8.3711 45673.66 1818.71
' 4.80 8.2852 45672.29 1837.50
4.70 8.1985 45670.85 1856.89
4.60 8.1108 45669.36 1876.90
' 4.50 8.0221 45667.80 1897.57
4.40 7.9325 45666.18 1918.95
4.30 7.8418 45664.48 1941.06
' 4.20 7.7501 45662.70 1963.96
4.10 7.6573 45660.83 1987.68
4.00 7.5633 45658.88 2012.29
3.90 7.4682 45656.83 2037.83
3.80 7.3718 45654.67 2064.37
3.70 7.2742 45652.39 2091.98
3.60 7.1752 45650.00 2120.73
' 3.50 7.0749 45647.47 2150.69
3.40 6.9731 45644.80 2181.96
3.30 6.8697 45641.97 2214.64
' 3.20 6.7649 45638.97 2248.83
3.10 6.6583 45635.78 2284.65
3.00 6.5500 45632.39 2322.24
2.90 6.4400 45628.77 2361.75
2.80 6.3279 45624.90 2403.35
2.70 6.2139 45620.75. 2447.23
2.60 6.0978 45616.30 2493.61
' 2.50 5.9793 45611.50 2542.73
2.40 5.8585 45606.32 2594.86
2.30 5.7352 45600.71 2650.35
' 2.20 5.6091 45594.61 2709.55
2.10 5.4802 45587.95 2772.91
2.00 5.3481 45580.67 2840.93
1.90 5.2127 45572.65 2914.22
1.80 5.0736 45563.79 2993.50
1.70 4.9307 45553.94 3079.62
' 1.60 4.7835 45542.94 3173.63
1.50 4.6316 45530.56 3276.82
1.40 4.4745 45516.53 3390.78
1.30 4.3118 45500.50 3517.54
' 1.20 4.1426 45482.00 3659.69
1.10 3.9662 45460.42 3820.60
' 1.00 3.7817 45434.91 4004.84
Orifice Constant = 0.6
Pipe diameter= 6
(in feet) 0.5
Number of Pipes = 5
Pond top surface area = 741
(S.F.)
Pond Bottom surface area = 42374
(S.F.)

0.90 3.5876 45404.30
0.80 3.3824 45366.89
0.70 3.1640 45320.13
0.60 2.9293 45260.00
0.50 2.6740 45179.83
0.40 2.3917 45067.60
0.30 2.0713 44899.25-
0.20 1.6912 44618.67
0.10 1.1959 44057.50
0.00 0 42374.00
4218.62
4470.84
4774.60
5150.32
5631.90
6281.01
7225.59
8794.21
12280.47
155649.29 Time (seconds)
1.80 Time (Days)
t
0

n

1

1
I?
7

30-ACRE DRAIN AGE A R E A
Figure 2b: Method 2 for OuantWong TN Export from Residential / Industrial / Commercial
Developments when Footprints of all impervious Surfaces are Shown
Step 1: Determine area for each type of land use and enter 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 for site 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) (2) (3) (4)
Type of Land Cover Area TN export coeff. TN export from use
(acres) (lbs/actyr) (Ib )
Permanently protected undisturbed 0.6
'open space (forest, unmown meadow) Z• O 1.2
Permanently protected managed 12
open space (grass, landscaping, etc.) 3. / 3,
Impervious surfaces (roads, parking 212
lots, driveways, roofs, paved storage
e
t
2
5710
Cv
ar
as, e
c.) 27 ,
- ,
TOTAL 32 .3 --- 59 1, ¢
The rule requires that all new developments achieve a nitrogen export of less than or
equal to 3.6 pounds per acre per year. If the development contributes'greater than 3.6
lbs/ac/yr of nitrogen, then the options shown in Table 2a are available based on whether
the de%elopment is residential or non-residential.
Table 2a: Nitrooen Evoort Reduction Anfinns
Residential Commercial / Industrial
If Me computed export is less than 6.0 If the computed export is less than 10.0
Ibs: acyr, then the owner may either. Ibs/ac/yr, then the owner may either.
1. Install BMPs to remove enough nitrogen 1. Install BMPs to remove enough nitrogen to
to bring the development down to 3.6 bring the development down to 3.6
Ibs/ac/yr. twac/yr.
2. Pay a one-time offset payment of $330/lb 2. Pay a one-time offset payment of S330JIb 10
to bring the nitrogen down to the 3.6 bring the nitrogen down to the 3.6 Wac/yr.
Ibs/ac/yr. 3. Do a combination of BMPs and offset
3. Do a combination of BMPs and offset payment to achieve a 3.61bs/actyr export
payment to achieve a 3.6 fWac/yr export.
If the computed export is greater than 6.0 N the computed export is greater than 10.0
Ibslac/yr, then the owner must use on-site IbWaclyr, then the owner must use on-site
BMPs to bring the development's export down BMPs to bring the. developrent's export down
to 6.0 Ibs/ac/yr. Then, the owner may use one to 10.0 Ibs/actyr. Then, the owner may use one
of the three options above to achieve the of the three options above to achieve the
reduction between 6.0 and 3.6 los/ac . reduction between 10.0 and 3.6 los/a
12
1
116 New Edition Court
' Cary, North Carolina 27511
Voice: 919.462.8474
&! Fax: [phone]
RICE &
ASSOCIATES CIVIL ENGINEERING & PLANNING
PROJECT: BY: DATE: SHEET NO. OF

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Y Q , V • 1, r I r Odd-1 ZONING, UNDEVELOPED r ~ DRIVE . i v, r Z
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r. o'•~ ON U•GTIO' , 1001 Navaho Drive ' rtow PROPOSED
~ NNO l~' :a Suite 220 TREATMENT ~
. U'N' • •1~EL PED~~~•: • o•N • o . D~ 0 • TM • 0 AREA ~ ~ Raleigh, N[ 21604 y z D
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• I f . . VICINITY MAP
, • • • ~l . : U IVISIOn
, • r ~ 4 f ~ BOM 1999 PG 36 ,
r • • l r: • . ~ ~s ..tee PIN# 0184.09-15-6808
. ~ ~ • • 40 EpW ~.R~,~D 5:~:~ , ~:~0' kE
o • . DRAINAGE AREA #l: 13.4 AC S ~ . PROJECT:
390
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W~ . i''' Q
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• ~ EXISTING PRO~~SED TREATMENT AREA .:i~tbil
. RALEIGH.., RELEASE POINTS 5'. OCTOBER 29,1999
~ O • • • ~ • r • • PRESCHOOL • r ' ~ r
, _ (IN FEET )
P tier 1 inch 100 ft.
"°e4lr#x D&AWING
'CRE . CIE LINE = e, yM,pAU1 M.k• v , J9
PROPERtt LINE
AND CREEK ;.~,i DRAINAGE EXHIBIT E-1
S:\AADWG\Trinity\smap.dwg Thu Oct 28 09:27:48 1999 Ted @ Rice & Associates

~
INV 384.84
h i I
so •I'
1 I EX. CI - - - - - RIM 388.71 4
~ INV 383.11 1 ~ Q
~J' NSF s ! PRINCIPAL DEVELOPMENT INVESTORS, LLC. _
~Q. BM 1996 PG 253 - ~ PIN~ 0784.09 15 0777 GUITER~==___=__- A _ ,CURB - 6 _ ~ _ - ~ - m ti ~ j ~
.q ZONING : 11 iINi,18 USE : COMMERCIAL EXIS-` - REVIEW REVISIONS _ _ . ' ~~o• ' • ' ~ '
ss~~='' 'ISYItJ~•~CENiERIINE^^-~•••....~;-_............................ ~O ~¢~fS ..CX - ~k
- - - - - - _ _ _ ti
iii ~i~- / y¢%' .........EXISTING 10' a . . ASPHALT WALK q m ~
y2~f - z.n....
~ GUTTER. -
xSnNG 30" CURB
U~ZEs~a'' RIM. 398.10 ,_=;;,-'T•~`";..,-.'_-' - RIM 386.51 .
~ G '•INV: 382.20,-'R.r•~ ~ &y~_ CURB ,.R~ m i _y ' INV 38'.9, fONSTRUQION REVISIONS
G 18~,,,=' sue, 3' x15Z1N,,;s- ss.~ ,4 fiyj-_ 42.7 8 d i ,,E ERISTING 10' ~gs ~ ,,N~ ± i Mme ~ a~.. r. \
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Ex,,~ q4. I ~ Z ~ ~ s~ I P F P I EX. CB
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, , d ~ I i 4 • • A' ~g • LE END r . . 1:
I r'I ~ ~ I ~ i ti I , v • • ) , IPF IRON PIPE FOUND NIP NEW IRON PIPE
I I ~ . . . • lu CP CALCULATED POINT ~ ~ / f.' ~ ,
I I tiJ' ~ ~ ' ~ I I i ~ a I I 'y ~ 4r : RI H WA 0 • • . / ' q' N/F NOW OR FORMERLY
5 r' POB POINT OF BEGINNING O ~ r h
I ..r•., y I O l 0 •1 DB DEED BOOK ' . N " ' ~ ~ 1 • BM BOOK of MAPS
1 I • ! 8~•• I PG PAGE ~ ~ ,3 EX. CB
I I f GREENWAY EASEMENT" . , I ,.1.. "&1:.:0•~CE F RUNE q A h ti ~ I RIM 379.90 R RADIUS , • ~ M t`~' 1 H L LENGTH / A . , i.
I 1 .....L•....... ti M y,;, CHD CHORD • /P % ll~ BH BORING HOLE LOCATION
FUTURE DEVELOPMENT . 1 I ~ ~ , i~' / rN.
p r6 N ~ Ik I 1 ~ . . r~~ rN LINE TABLE ~1 ~ / /N r/r LINE LENGTH BEARING
AIL ~R;4UTLE ~5;:::~;:••yq•;::~:~~'~',':::':•...: ~ 4 . PROPOSED ae/ .r,y e~ '38$• L1 27.25 S76'15'Ol"E
I ~3•...,.,I.• . ' C 1 '•:s.:~ , f ' ~ .385 S • . , "CnNVEN4EN.CE' ~ ! . p 2/ N L2 50.59 S74'46'S7"E
' E~ F E STORE • 0 O : • • • , f,, I L3 12.91 '54"W N N70'28 . , r FFE = 383.00 ~ / /N
/ / ' ~ o ~~p/ Q W• ~ /N ~ rp g ,,w.u( CURVE TABLE , : . to ~ Q W ....•ti lu .
• , . , '•F4.Dpb:p AaN:". "GREEN~VAY;:EA ENT "Y53•• • / . , / 5 :••GIc~E~cE••&°.n'SS©e:••s;;76- ............................$r...TO••CENd~Q,I'INE.::;:°....,.•.... • . a ' r • l3' ~ Yn • Q S03'10'11"W , ' ~Ut C1 318.11 899.93 316.46
1 6. • . . ~ ~ 3 ..~ICFILANIJ'CRE6K;, . , q A ~ ~ ~ rti "Y'N 3 C2 57.77 35.00 51.43
FILTER OUTLET#~ ¦ " •:it:ICI:R•.~.:1~.'.~:•....:~~,......•. ~ l~ ~ h 2 ~111'O
• ' ~ F,LO©ti 3'LAIN aY ~i.1~H J. s.r'.~•/. ' a 5 ~}•E'. . • • ~ ~ ~ ••v ~ ~ NOTES
. 6...... . °~hLE~~E & Assoc. • / / y" , • , 1N c~ ~ rN
~ OOD AI1t . . . . . ~ ~ L....,,... . ~~5• •W ! ~!u ~ 1) AREAS CALCULATED BY COORDINATE GEOMETRY.
• ' 11 ¦ ~ ~ ~ ¦ ¦ ¦ ~ FILTER OUTLET'#3 . FILTER OUTLEt #4 . ~ r k•/d 'c / n • h „ N 2) SURVEYOR HAS MADE NO INVESTIGATION OR INDEPENDENT
. ~ • ' • r ~ ~ y, VE , '375• ` SEARCH FOR EASEMENTS OF RECORD, ENCUMBRANCES, RESTRICTI • I • u
. ~ Tract 5 I ~ - ~ • ' COVENANTS, OWNERSHIP TITLE EVIDENCE OR ANY OTHER FACTS r ,L'OO•~~~~FEAIH••••• ~ ~ ~ r ' • lk THAT AN ACCURATE AND CURRENT TITLE SEARCH MAY DISCLOSE.
P ED- . . R P T 1 , ' . 9 0 OS rltl t Assoc ates...~L£ 'TrR . .i~. ~ 1 ll/ TER
v . ~ B.M. _1996, PG._1835 FLOOD WAY ' ~ ) : ' ' : 3 Sll P IA FOOD . . ~ r I rN ) BJECT PROPERTY IS LOCATED IN A S EC L L ~ ® HA A 116 New Edltlon Courf I,~• -r^- y ~r ! Z RD ZONE PER FLOOD INSURANCE RATE MAP (F.LR.M.)
, ' ' PIN `:0784:09.1.5. - 864 I ! , . 52 . . • • . . . . ' .`4.39 ACRES: ~ d lam: a ;r 1N 3718300318 E, EFFECTIVE DATE MARCH 3, 1992. FILTER OUT... 6.`_--- ~ ~ r ' , . r, Ca(~f North Carolina 27511
• 6:31 , . ~ r ~ • , I . . ~ ~ r V r IN 'j1 • GREENIyAY EASEMENT T ! ~ 4} THE LOCATIONS OF UNDERGROUND UTILITIES AS SHOWN HEREON
. r i o N z~ i' • m . . ; 81', CENTERLINQ ~ r ~ ; • ARE BASED ON ABOVEGROUND STRUCTURES AND RECORD 'RI~HEAND C l:EK r DRAVa1NGS PROVIDED THE SURVEYOR. LOCATIONS OF UNDERGROUND VOI~e: 919,402,0414
. . . • ~ . . • o ~ r ~ , ~ ~ ® ~ ! R N. ~ ~ • ? r UTILITIES/STRUCTURES MAY VARY FROM LOCATION SHOWN HE EO
~ r o . • . •37 p • z . ~ . . •::h • D N . . • ~ ~ ~ ~ ! ~ ADDITIONAL BURIED UTILITIES STRUCTURES MAY BE ENCOUNTERED. ' ~ .Q r„ l fax. 919.462,8101 PROPOSED • , r „ • ~ l~ ; _ ~ I rN NO EXCAVATIONS WERE MADE DURING THE PROGRESS OF THIS
. m • . s . ~Mi1• ~'~~l . ~ '3 • T 'I O rp SURVEY TO LOCATE BURIED UTILITIES/STRUCTURES. >>v Rlceassoclates@te
w !7 { ' ZD ~ ~ ~,d ~+C T ~ry~' I' _ r ~ !O 5) FLOODWAY ~ FLOOD PLAIN LOCATIONS AS PER PLAT RECORED
,~l PRO OS :k • f IP~SED 1 I~EA I IrIGH, l /'~IREA ~ • ~ / IN BOOK OF MAPS 1996, PAGE 1835. ~ ! RI 371.89
v . ' .X:'•.86"'•FES' . . h • ` I : ? FLOOD WA . ' U' 3.68 25 'I r' r O 1 6) ALL DIMENSIONS ARE TO BACK OF CURB UNLESS O(~
~ 3~'••• E ~ ' ~ ~ o PROPQSED TR A~`MENT AR , e:: ~ti • r, I 1 OTHERWISE NOTED. ~0 ,°°°•°'°ee, N.~ A o ° pFESSIOp i .
• . • . e e i~ r r e ~ ::I:::::..... rr = SEAL .
• • ' FipoD war• • • . r : o ° 8293 e
. , r. . : . ; - ~ ,
~ :95x•. .k1yq r,~,• , ~,b• S08.gjs~•.. 509S2'35 ! eeeNGINEE°°e W , I V ee°eese [i 5067512"E ~ r ^
. Y ~ • . i : FLOOD WAY . . ' ' • •h„°: ~ r•' ~ ; ~ 1,,:...;;:,:•55,,76 O • •X6;. 28.88' , 76'';;.;;::;;....••.. • ,.EXISTING ~ IP i5,• ...,....$998:......,, a~................. , F~ f R~
? ? ~ ~ • •9'• 56'.45 '36 8' •365, ........,...:....8o- ..NEADWALI: 4~~ N M'
. , • ~ ~ N ) r ~~q~up~~ I
? ~k • 1 ~ EXISTING v • ' I HEADWALL
n .,q . 1 ` VEL PER: FLOOD WAY DE 0 ' I ' 1 I
~ ~ ~ ~ FLOOD WAY >J , •m , ' i r ' ! I
..y r ~ . ~ M ..W..•' ~ ~ i : ~ r 1„~ ~ ,
RICHLAND CREEK CENTERLINE ~ 4g'~ / ~ 4 '444 11 ~ r ' 1~ I EXI T. CB
' RI 370.52 A
M A~~1! A~~ I , N 1001 Navaho Drive I ! EXI T. CB
r RI 370.52 I Suite 220
. ~1 ~I rMI ¦ ~ FLOOD PLAIN BY HUGH J. I lu ` rN Ralei h NC 21604
~ / ~ ~ ~r GILLEECE & ASSOC. 5-16-96 I~ ~ / IN 9 , - - ~ 919.954.0840
~ '1R ~¦®¦¦1N1 . r ui ~ rN
~ ®~NI~If¦ ~ ~ GREENWAY EASEMENT ~ ~ru
~ i 4* 81' TO CENTERLINE ! ui SITE: RICHLAND CREEK IN
\ ~ ~ FLOOD PLAIN BY HUGH J. GREENWAY EASEMENT ~-GILLEECE & ASSOC. 5-16-96 r rN
81' TO CENTERLINE I rN rac o ,Ir ~
RICHLAND CREEK 1 IN 1N nnl
I IN ui I ni
In ssoaa es
EXISTING 40' CITY OF RALE]GH •II ~ I IN
SANITARY SEWER EASEMENT MB 1979 PG 370 1 III rN U IVISI011
IN
\ , BOM 1999, PG 36
\ STRUCTURE ELEVATIONS PIN# 0184.09-15-6808
\ AREA, Q-10, CUMUL. PIPE PIPE PIPE VEL., \ STRUCT. ACRES CFS CFS DIA. LENGTH SLOPE FPS TOC TOP INV. IN INV. IN INV. OUT
\ 1, CONTRACTOR SHALL L OR SHALL LOCATE ALL EXISTING UTILITIES TO VERIFY PROIEC>•:
\ CB 1 - - 382.50 - - 378.50 LOCATIONS, DEPTHS, ~ DEPTHS, AND ELEVATIONS PRIOR TO STARTING ANY
\ - - 18 72.84 4.65 - _ CONSTRUCTION ACTIVI~ CB 2 - - 382.60 375.11 375.00 TO THE OWNER, ENGIN N TION ACTIVITIES. ANY DIFFERENCES SHALL BE REPORTED use IVBr e
18 25.86 4.56 FES 3 - - JVNER, ENGINEER, AND ARCHITECT.
assn u er SING, INCLUDING CLEARING & GRUBBING AND CUTS & FILLS ,
- 375.92 2. SITE GRADING, INCLUD CB 10 - - - 379.92 - TO BE IN ACCORDANC ACCORDANCE WITH DEVELOPERS GEOTECHNICAL ENGINEER B
SDMH 7 - 18" 32.34 .............5:1.9%........................ 371.74 48" 378.50 ( ) 374.24 (18) INVESTIGATION, RECOM . 1 P 1 Isur ance l-ION, RECOMMENDATIONS, AND CONSTRUCTION GUIDELINES. ~ '
CB 4 - - 48" 29.86' 1.27 - 3, CONSTRUCTION OF ALA arlance TION OF ALL PROPOSED STORM DRAINAGE FACILITIES SHALL
SDMH 5 - - 385.0 373.25 373.25 BE IN ACCORDANCE W - 48 102.83 1.27 - AND SPECIFICATIONS ~ ;ORDANCE WITH CITY OF RALEIGH AND/OR NCDOT STANDARDS GRAPHIC SCALE 5201 Edwards MITI Road
CB 6 - - 379.92 371.94 - 371.94 IFICATIONS AS APPLICABLE. 30 0 ,5 ~ so 120 Ralei h NC
- 48 16.00 1.27 - SDMH 7 - - 378.50 371.74 (48") 374.24 (18") - 4. EACH STORM DRAINAC 9~ RM DRAINAGE STRUCTURE SHALL BE PROVIDED WITH INDIVIDUAL
- 48 57.89 1.27 CB 8 - 375.25 371.01 - 370.01 EROSION CONTROL. h ~ONTROL. MEASURE IN ACCORDANCE WITH CITY OF RALEIGH
_ OQOBER 29,1999 _NTS OR AS DIRECTED BY THE CITY EROSION CONTROL ENGINEER. ~ IN FEET ~
FES 9 - 48" 22.00' 1.97% - 369.58 REQUIREMENTS OR AS
NOTE: 1. ALL VALUES BASED UPON RATIONAL FORMULA; 10 MINUTE TIME OF CONCENTRATION RUNOFF FACTOR (C) = 0.9, oeawiNc
RAINFALL INTENSITY (1) = 7.5 IN/HR, AREA (A) = VARIES
2. ALL STORM DRAIN PIPE SHALL BE CLASS III RCP RELEASE EXHIBIT E-2
S:IAAOWG\Trinitylbase.dwg Thu Oct 28 15:22:08 1999 Ted @ Rice 6 Associates

50' NEUSE RI DER BASIN RIPARIAN BUFFER APPROXIMA TEL Y 200 FEET TO EDWARDS MILL ROAD
~ 8' 15' PA THWA Y BERM l/ARIES 50'-130' DEl/ELOPED S/TE (BY OTHERS
Q
m
TREATMENT AREA Q S/ TE
a 4.25' 6.5' 4.25' EXISTING EMBANKMENT
Q 0
AlN STORM DR
~ ' ~AANHOLE
S' WIDE WALKWA Y W
v

0 z ' ~ I jE M S
Q J ~ I FRp ~pW
Z I 10- YR WSEL = 72.04 ~ =1~~ INF
2 111111=_ 5- YR WSEL = 71.83 ~ GRA DEL & RlP RAP FlL TER
111111= ~ 1~ - I
2- YR WSEL = 71.36 I
MUL T/PLE 6 " PVC PIPES I
~-,-FLOW ...-FLOW FLOW . J I
FLOW-~ Illll~lllh I 111111=~
IIIII~IIIII~IIII~ IIIII ' _ TREA TMENT AREA BOTTOM ± 70.00' 111111~11111~11111= 111111.111111= _________J
IIIII~IIIII~IIIIiI 111111=
SETTLING POOL
W
°
116 New Edition Caurt
° Ca NalthCaroli~a21S11
J N.
Voice: 919.462.8414
Faz: 919.462.8107
. . . . . . Rlceassocl el Ix.com t
CLASS 1 RIP RAP
, . 11,111111,,,,, roRM , S STORM .,`'`I caRo
~ FAD STORM w 375 DRAIN 375 e„e..e,, ~/N ' DRAIN ~ e 9 . ' ' ANHOL
" / MANHOLE MANHOLE M E r ~ Q~° ~ = e SEAL
Flow / / e e
:8293: • ee °e° ;
/ ~ / b ' • • ' ' ' ~ O , O I, S~' eseesee •
ill'' C \ 1`~ ~ VfN M. R 1~`•
I ~ _ I INVERT I 370. ~ ~ 111111111111111 ~ 370
PIPE I --1--- J / FLOW ~ Q ~ O O
i SeTT~rN ~i
G Pool AREA--- ~ SETTLING POOL ETTLING PODL DEVELOPER: SETTLING POOL S
~ ~
_"r~`i
_ ~ 0 i
~y p5 WASHED STONE. 1' THICK X 3' HIGH MIN. RIP RAP FIL TER R 1001 Navaho Drive RIP RAP FILTER RIP RAP FIL TE
Suite 220
PERSPECTIVE VIEW NO SCALE Raleigh, N[ 27604
919.954.0840
PLAN VIEW OF RELEASE
SITES:
MODIFIED GRAVEL & RIP RAP HORSESHOE OUTLET
rac o
nnl
ssocla es
u Ivislon
5 FT BOM 1999, PG 36
MIN
0 1.5 FT p~ PIN# 0184.09-15-6806
o~~
Op ~ 5 FT 12" MIN. MAX PROJECT:
~ 0 p °o
O o ° Buse aver
FILTER assn u er
CROSS SECTION FABRIC SETTLING POOL FIPERT
Isur ance
MAINTENANCE
ariance
INSPECT RIP RAP FILTERS AFTER EACH PERIOD OF SIGNIFICANT RAINFALL. REMOVE SEDIMENT AND RESTORE FILTER TO ITS ORIGINAL DIMENSIONS WHEN THE SEDIMENT HAS ACCUMULATED TO ONE-HALF THE DEPTH OF THE SETTLING POOL. PLACE THE SEDIMENT THAT IS REMOVED IN 5201 Edwards Mill Raad
A DESIGNATED DISPOSAL AREA AND REPLACE THE CONTAMINATED PART OF THE GRAVEL FACING.
CHECK THE RIP RAP FILTER FOR DAMAGE FROM EROSION. ANY RIP RAP DISPLACED FROM THE SPILLWAY MUST BE REPLACED IMMEDIATELY. Ralei h NC 9•
STABILIZE THE EMBANKMENT AND ALL DISTURBED AREAS ABOVE THE SEDIMENT POOL AND DOWNSTREAM FROM THE TRAP IMMEDIATELY AFTER
CONSTRUCTION WITH SEEDING. OQOBER 29,1999
oeawirvG
GRAVEL & RIP RAP FILTER
STORM DRAIN TREATMENT DETAILS E-3
L- i
S:\AADWG\Trinity\Treatment.dwg Thu Oct 28 08:49:03 1999 Ted @ Rice 6 Associates