20070017 Ver 2_Minor Variance_20071126

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Transmittal Sent Via:
^ Regular Mail ^ FedEx ^ UPS
^ Certified Mail ®Courier ^ Pick-up
TO: Ms. Amy Chapman
NCDENR-Divison of Water Quality
401/Wetlands Unit
1650 Mail Service Center
Raleigh, NC 27699
WE ARE SENDING
^ Shop Drawings
^ Copy of Letter
® Attached
^ Prints
^ Change Order
DATE: 11/26/07 TWC No.: 2664-I
RE: Terrington Pump Station & Force Main
Request for Minor Variance -Response to
Comments Cary, NC
^ Under separate cover via _
^ Plans ^ Samples
^ Other
COPIES DATE NO. DESCRIPTION
1 11/15/07 Original Transmittal Letter
1 11/15/07 Original Variance Request Form -for Minor Variances
1 11/21/07 Bioretention Inspection and Maintenance Agreement
1 11/25/07 Construction Drawings (Sheets 6, 9, and 17) showing improvements
1 Bioretention Cell Supplement
1 Supporting Calculations (including nitrogen export, flow, outlet
structure, Bioretention sizin ,and inlet
1 11/20/07 NCEEP acceptance letter
THESE ARE TRANSMITTED as checked below:
^ For Approval ^ Reviewed ^ Revise and Resubmit
^ For Your Use ^ Rejected ^ Submit Copies for Distribution
^ As Requested ^ Corrected ^ Return Corrected Print
^ For Review and Comment ^ Other:
^ For Bids Due [ ] ^ Prints Returned after Loan to Us
REMARKS: Amy,
Per our conversations over recent weeks, I believe we have covered all items requested
from your initial review. Thus, hopefully we are in compliance and will be in a position to
receive the minor variance. If there is anything else required to complete the application
or if you have any questions, please do not hesitate to contact me. Also, we appreciate
your helpfulness throughout this process.
Thanks,
SIGNED: 'i'•
W. Brian Johnson, P.E.
COPY TO: Ken Schuster, P.E. -Town of Cary (Transmittal only)
the following items:
^ Specifications
If enclosures are not as noted, kindly notify us at once.

THE
WOOTEN
COMPANY
ENGINEERING
November 15, 2007
Ms. Amy Chapman
Division of Water Quality
401/Wetlands Unit
1650 Mail Service Center
Raleigh, NC 27699-1650
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PLANNING
Re: Request for Minor Variance
A R c H I r E c r u R E Terrington Pump Station and Force Main Project
Town of Cary, North Carolina
TWC No. 2664-I
Dear Ms. Chapman:
On behalf of the Town of Cary, please find enclosed, two (2) copies of the following
items regarding the above referenced project for your review.
• Variance Request Form -for Minor Variance
• Site Plan -Option 1
• Site Plan -Option 2
• USGS quad map showing the location of project
This project was originally permitted in February 2007 as DWQ Project # 2007-0017
providing authorization to impact some Zone 2 buffer areas associated with the project.
Construction began ~on the project earlier this year and it is nearly complete. More
specifically, all structures are installed and the only remaining work is the site items (e.g.,
concrete pad, asphalt drive, minor grading, etc.). Recently it was discovered through a
Town quality control check that the pump station site was located within a riparian buffer
that encroaches onto the southern portion of the site.
Given the space constraints of the site as explained in the variance request form, the
options for eliminating/minimizing the buffer impacts are limited. Although some
disturbance has already been done to Zone 1 of the buffer, worked has since been
stopped. All proposed work in this zone has been eliminated and this area will be
restored to original grade with riparian plantings. In Zone 2, we have eliminated some of
the proposed impervious areas (e.g., driveway and stone ground cover) within the pump
station site to keep these areas to a minimum but some impervious around the pump
station structures still remains.
We have provided two (2) site plan options with this variance request. Both present an
option for tying the proposed grade to the existing grade before entering into Zone 1.
Option no. 1 includes the use of a retaining wall along the Zone 1 boundary to
120 North Boylan Avenue accomplish this. The use of the wall would allow a 2:1 slope to be established, which can
Raleigh NC 27603-1423 be stabilized with vegetation. The only issue with the wall is that it would add
approximately 70 sq. ft. of impervious area in Zone 2. Option no. 2 eliminates the wall
but creates slopes of approximately 1.4:1, which would need to be stabilized (e.g., rip-
919.828.0531 rap). Note that the impervious area indicated in the variance application is a worst case
fax [phone]

Ms. Amy Chapman
November 15, 2007
Page 2
as it assumes the retaining wall option. We request that Division of Water Quality
evaluate both options and determine which would best support the variance request.
We have applied to the NCEEP for an In-Lieu payment for the impervious amount in
Zone 2 and hope to receive this approval in the very near future. Upon receipt we will
forward the approval letter to you.
As indicated above, this project is currently under construction. Thus, an expeditious
review would be greatly appreciated so that we might avoid any delay claims from the
contractor. We look forward to your response. In the meantime, if you should have any
questions or need further information, please do not hesitate to contact me.
Sincerely,
THE WOOTEN COMPANY
W. Brian Johnson, P:E.
Enclosures: As stated.
cc: Mr. Ken Schuster, P.E. -Town of Cary

~ OFFICE USE ONLY: Date Received Request # ______
State of North Carolina
Department of Environment and Natural Resources Q~ O ~ ~ ~ v 2
Division of Water Quality
~ 3 ~. ~-
Variance Request Form -for Minor Variances
Protection and Maintenance of Riparian Areas Rules
NOTE: This form maybe photocopied for use as an original.
Please identify which Riparian Area (Buffer) Protection Rule applies.
~ Neuse River Basin: Nutrient Sensitive Waters Management Strategy
Protection and Maintenance of Riparian Areas Rule (15A NCAC 02B
.0233)
^ Tar-Pamlico River Basin: Nutrient Sensitive Waters Management
Strategy Protection and Maintenance of Riparian Areas Rule (15A
NCAC 02B .0259)
^ Catawba River Basin: Protection and Maintenance of Existing Riparian
Buffers (15A NCAC 02B .0243)
Part 1: General Information
(Please include attachments if the room provided is insufficient.)
~ a•,
~~
~i~V ~ ~ 2007
t~FPJ~t - wA7ER QUALITY
1. Applicant's name (the corporation, individual, etc. who owns the property): +Mt`ft.~ND~~u"?O~TO~M!:vATE-~9R~H
__Town of Ca_ry__ ___ _ _ __
2. Print Owner/Signing Official (person legally responsible for the property and its compliance)
Name: Tim Bailey, P.E.
~ _._._ _~ ~~~~~
~
~
_
Title: Director of Engineering
_
_
_
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Street address: 31 s N. Acaaamy st.
____
City, State, Zip: _Cary, NC 27511
Telephone: 919 },469-4030 _ _. _. _._._ _
Fax: X919 _) 460-4935 ~_ ~,_______ __
3. Contact person who can answer questions about the proposed project:
Name: W. Brian Johnson, P.E,
Telephone: ~,~}828 0531 _~_._....~___..____.._. __.___. __.______ ____.____.
Fax: 919 _} 834-3589.._ _____ ___ _.._____ _.______ ~___ _._ __...__ _____ _--
Email: [e-mail]
4. Project Name (Subdivision, facility, or establishment name -consistent with project name on
plans, specifications, letters, operation and maintenance agreements, etc.):
Terrington Pump Station and Force Main
Version 2: November 2002

5. Project Location:
Street address: 5956 Terrington Lane
City, State, Zip: Cary, NC
COUnty' Wake County
Latitude/longitude: _ 35 degrees, 43.91' N, 78 degrees 44.42' W (NAD 83)
6. Directions to site from nearest major intersection (Also, attach an 8 YZ x 11 copy of the USGS
topographic map indicating the location of the site):
From the intersection of Campbell Rd. and Tryon Rd, travel South along Campbell Road until
_coming_to the Terr~ton„subdivision. Turn right'into the subdivision_onto Terrington Lane___ Follow
_to_„the en..d....of the, _road.
7. Stream to be impacted by the proposed activity:
Stream name (for unnamed streams label as "UT" to the nearest named stream):
UT to Swift Creek __
Stream classification [as identified within the Schedule of Classifications 15A NCAC 2B
.0315 (Neuse) or .0316 (Tar-Pamlico)]: ws - lll~ Nsw _
8. Which of the following permits/approvals will be required or have been received already for
this project?
Required: Received: Date received: Permit Type:
.. _ ___
----- -_ CAMA Major
CAMA Minor
_
x x 2/9/07_ 401 Certification/404 Permit
On-site Wastewater Permit
NPDES Permit (including stormwater)
x _ x ~~ Non-discharge Permit
Water Supply Watershed Variance
X _
_
M X ._ 1/4/07 Others S ecif Town of Cary stormwater
(P Y) __.___.._.____.___.
X X 4/26/07 Erosion Control
Part 2: Proposed Activity
(Please include attachments if the room provided is insufficient.)
Description of proposed activity [Also, please attach a map of sufficient detail (such as a plat
map or site plan) to accurately delineate the boundaries of the land to be utilized in carrying
out the activity, the location and dimension of any disturbance in the riparian buffers
associated with the activity, and the extent of riparian buffers on the land. Include the area
of buffer impact in ftZ.]:
Construction of a new wastewater pumping station and force main to serve the Terrington
subdivision and upstream drainage basin. The total buffer impact to Zone 2 only will be 2 550 sf
including grading and impervious cover._ The_total impervious area will be 375 sf. Note. that no,,
ermanent im acts are ro osed in Zone 1 some tem im acts have occurred but it will be re-
p P P P ~~_...... __.(___._._ p• P ~._....
stored to original grade vegetation).
State reasons why this plan for the proposed activity cannot be practically accomplished,
reduced or reconfigured to better minimize or eliminate disturbance to the riparian buffers:
The pump station is surrounded by environmental features on all sides (i e. buffers wetland,
and a stormwater BMP . There is no other location on-site that would eliminate the disturbance.
Note that some reductions of proposed improvements have occurred They are: 1)the asphalt
drive has been shortened to avoid the buffer, 2) the stone groundcover within the site has been
eliminated within the buffer.
Variance Request Form, page 2
Version 2: November 2000

3. Description of any best management practices to be used to control impacts associated with
the proposed activity (i.e., control of runoff from impervious surfaces to provide diffuse flow,
re-planting vegetation or enhancement of existing vegetation, etc.):
The buffer outside the proposed fence will be replanted with riparian plantings to ensure re-
establishment of the buffer. All stormwater will enter the buffer diffused (i.e. ,sheet flow). Note that
all runoff from impervious surfaces will drain into a new dry detention basin before being discharged
into an existing ditch. Additionally, a nitrogen off-set payment has already been made to the NCEEP
for the entire site (including the impervious surfaces within the buffer).
4. Please provide an explanation of the following:
(1) The practical difficulties or hardships that would result from the strict application of this
Rule.
B strict a lication of this rule the um station would have to be relocated to another site down-
stream onto land that is not owned by the Town or within the Town limits. The Swift Creek Land
Mana ement Plan recludes the Town from extendin an further south downstream than the site
where the pump station is located. Additionally all the infrastructure at the site (already constructed)
would have to be relocated. This would be extremely time Consuming and costly.
(2) How these difficulties or hardships result from conditions that are unique to the property
involved.
With environmental features on all 4 sides of the site, there is limited space to locate a pump
station. The hardships described above are a result of this limited space. Note that we have been
able to avoid disturbance to other features, except exempt buffer impacts with the force main and
_impacts in the wetlands for the force main approved under Nationwide 12. _ _
The space required for the pump station and the limited site has made the buffer impact necessary.
(3) If economic hardship is the major consideration, then include a specific explanation of the
economic hardships and the proportion of the hardship to the entire value of the project.
Economic hardship resulting from a relocation is a major consideration. The total project cost is
approximately $900,000. The relocation would affect approximately 73% of this cost. Most of this
cost has already been paid to the contractor for portions of the station that have already been built.
....
Therefore, relocation_would result in a repayment of a large portion of dollars that have already been
paid. Additionally, a new site would have to be acquired, project redesign cost incurred, and permits modified.
Part 3: Deed Restrictions
By your signature in Part 5 of this application, you certify that all structural stormwater best
management practices required by this variance shall be located in recorded stormwater
easements, that the easements will run with the land, that the easements cannot be changed or
deleted without concurrence from the State, and that the easements will be recorded prior to the
sale of any lot. N/A
Part 4: Agent Authorization
If you wish to designate submittal authority to another individual or firm so that they may provide
information on your behalf, please complete this section:
Designated agent (individual or firm): The Wooten ,company
Mailing address: 120 N. Boylan Avenue
City, State, Zip:. _ _. _ _ Raleigh, NC 27603
Telephone: _ (9~9) 828-053 „_ __ _._ __._.
Fax: [phone]
Email: ~ ~.. [e-mail]
Part 5: Applicant's Certification
Variance Request Form, page 3
Version 2: November 2000

1, Tim Bailey, P.E, ___ _~ (print or type name of person
listed in Part I, Item 2), certify that the information included on this permit application form is
correct, that the project will be constructed in conformance with the approved plans and that the
deed restrictions in accordance with Part 5 of this form will be recorded with all required permit
conditions.
Signature:
Date:
Title:
Variance Request Form, page 4
Version 2: November 2000

Bioretention Inspection and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
Important inspection and maintenance procedures:
- Immediately after the bioretention cell is established, the plants will be watered
twice weekly if needed until the plants become established (commonly six
weeks).
- Snow, mulch or any other material will NEVER be piled on the surface of the
bioretention cell
- Heavy equipment will NEVER be driven over the bioretention cell.
- Special care will be taken to prevent sediment from entering the bioretention cell.
- Once a year, a soil test of the soil media will be conducted.
After the bioretention cell is established, I will inspect it once a month and within 24
hours after every storm event greater than 1.0 inches (or 1.5 inches if in a Coastal
County). Records of inspection and maintenance will be kept in a known set location
and will be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential roblems: How I will remediate the roblem:
The entire BMP Trash/debris is resent. Remove the trash/debris.
The perimeter of the Areas of bare soil and/or Regrade the soil if necessary to
bioretention cell erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer a lication.
The inlet device: pipe, The pipe is clogged (if Unclog the pipe. Dispose of the
stone verge or Swale a licable). sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged (if
a licable).
Erosion is occurring in the Regrade the Swale if necessary to
Swale {if applicable). smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future roblems with erosion.
Stone verge is clogged or Remove sediment and clogged
covered in sediment (if stone and replace with clean stone.
a licable).

BMP element: Potential roblems: How I will remediate the roblem:
The pretreatment area Flow is bypassing Regrade if necessary to route all
pretreatment area and/or flow to the pretreatment area.
llies have formed. Restabilize the area after radin .
Sediment has accumulated to Search for the source of the
a depth greater than three sediment and remedy the problem if
inches. possible. Remove the sediment and
restabilize the retreatmerit area.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
revent future erosion roblems.
Weeds are present. Remove the weeds, preferably by
hand.
The bioretention cell: Best professional practices Prune according to best professional
vegetation show that pruning is needed practices.
to maintain optimal plant
health.,
Plants are dead, diseased or Determine the source of the
dying, problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide aone-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessa
Tree stakes/wires are present Remove tree stake/wires (which
six months after lantin can kill the tree if not removed).
The bioretention cell: Mulch is breaking down or Spot mulch if there are only random
soils and mulch has floated away. void areas. Replace whole mulch
layer if necessary. Remove the
remaining much and replace with
triple shredded hard wood mulch at
a maximum de th of three inches.
Soils and/or mulch are Determine the extent of the clogging
clogged with sediment. -remove and replace either just the
top layers or the entire media as
needed. Dispose of the spoil in an
appropriate off-site location. Use
triple shredded hard wood mulch at
a maximum depth of three inches.
Search for the source of the
sediment and remedy the problem if
ossible.
An annual soil test shows that Dolomitic lime shall be applied as
pH has dropped or heavy recommended per the soil test and
metals have accumulated in toxic soils shall be removed,
the soil media. disposed of properly and replaced
with new lantin media.

BMP element: Potential roblems: How F will rernediate the roblem:
The underdrain system Clogging has occurred. Wash out the underdrain system.
(if a licable)
The drop inlet Clogging has occurred. Clean out the drop inlet. Dispose of
the sediment off-site.
The dro inlet is dama ed Re air or re lace the dro inlet.
The receiving water Erosion or other signs of Contact the NC Division of Water
damage have occurred at the Quality 401 Oversight Unit at 919-
outlet. 733-1786.

I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Iirint name:Tim Bailey. P.E.
Title:Director of Engineering
Note; The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
a Notary Public for the State of
Co ty of ~~(~~J~ , do hereby certify that
~~"(
personally appeared before me this
and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
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SEAL
My commission expires~,~ ~~~
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Address:P.O. Box 8005, Carv. NC 27512-8005

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STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
BIORETENTION CELL SUPPLEMENT
~F W A r'`9
O~ /~
>> ~C~,I.lC~, r_
~.._ _.
This form must be filled out, printed and submitted.
The Required Items Checklist (Part III) must be printed, filled out and submitted along with all of the required information.
I• PROJECT INFORMATION.
Project name Terrington Pump Station and Force Main
Contact name Brian Johnson
Phone number 919-828-0531
Date November 26, 2007
Drainage area number nla
II. DESIGN INFORMATION
Site Characteristics
Drainage area 1,000 ftz
Impervious area 526 ft2 (TKCt~1,t~1(T TfifE (~~ORETENT76>`/ t4REr~- , 7-ryE
Percent impervious 52.6% % AC,TUtFt, ~-~tpERVttrvS A-eFA IS 356 59.$}•)
Design rainfall depth 1.0 inch
Peak Flow Calculations
Is preipost control of the 1-yr, 24-hr peak flow required?
1-yr, 24-hr runoff depth
1-yr, 24-hr intensity
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
PrelPost 1-yr, 24-hr peak control
Storage Volume: Non-SR Waters
Design volume
Ponding depth of water
Ponding depth of water
Surface area of the top of the bioretention cell
Length:
Width:
-or- Radius
Storage Volume: SR Waters
1 yr, 24-hr depth
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
f~linimum volume required
Volume provided
Soils Report Summary
Drawdown time, ponded volume
Dra~.vdown time, to 24 inches below surface
Drawdown time, total:
In-situ soil,
Soil type
Soil permeability
Planting media soil:
Soil type
Soil permeability
Soil composition
°~o Sand (by weight)
Permit Number:
(to be provided by DWQ)
N
(Y or N)
in
in/hr
ft3/sec
ft3/sec
ft3/sec
44.0 ft3
9 inches OK
0.75 ft
133.0 ft2 OK
15 ft OK
10 ft OK
n/aft OK
in
ft3
ft3
ft3
ft'
4.5 hr OK
12 hr OK
16.5 hr
unknown
unknown in/hr
S~~ Il~rkll~s'~li~)
2.00 in/hr OK
~ ~ETR/~0% Sand should be ~85-88%
Form SW401-Bioretention-Rev.1 Parts I and 11. Design Summary, Page 1 of 2

Fines (by weight)
i % Organic (by weight)
Phosphorus Index (P-Index)
Basin Elevations
Temporary pool elevation
Planting elevation (top of the mulch)
Bottom of the cell
Planting depth
Depth of mulch
SHWT elevation
Are underdrains being installed?
DfTfj/LO%
~~ XaE'TfiILO%
Total: 0%
How many clean out pipes are being installed?
What factor of safety is used for sizing the underdrains? (See
BMP Manual Section 12.3.6)
Additional distance between the bottom of the planting media and
the bottom of the cell to account for underdrains
Bottom of the cell required
Distance from bottom to SHWT
Type of bioretention cell (answer "Y" to only one of the two
following questions):
Is this a grassed cell?
Is this a cell with trees/shrubs?
Planting Plan
Number of tree species
Number of shrub species
Number of herbaceous groundcover species
Additional Information
Does volume in excess of the design volume bypass the
bioretention cell?
Doas volume in excess of the design volume flow evenly distributed
through a vegetated filter?
What is the length of the vegetated filter?
Does the design use a level spreader to evenly distribute flow?
Is the BMP located at least 30 feet from surface waters (50 feet if
SA waters)?
Is the BMP localed at least 100 feet from water supply wells?
Are the vegetated side slopes equal to or less than 3:1?
Is the BMP located in a recorded drainage easement with a
recorded access easement to a public Right of Way (ROW)?
Inlet velocity (from treatment system)
Is the area surrounding the cell likely to undergo development in
the future?
Are the slopes draining to the bioretention cell greater than 20%?
is the drainage area permanently stabilized?
Pretroatment Used
(Indicate Type Used with an "X" in the shaded cell)
Gravel and grass
(8'inches gravel followed by 3-5 ft of grass)
Grassed Swale
Forebay
Permit Number:
(to be provided by DWQ)
Fines should be -8-12%
Organic should be ~3-5%
10 (unitless) OK
363 fmsl OK
362.5 fmsl
359.75 fmsl
2.75 ft
3 inches OK
354 fmsl OK
Y (Y or N)
1 OK
16
1ft
358.75 fmsl
4.75 ft OK
N (Y or N)
Y (Y or N) Insufficient media depth ~Y"Q~£SIS~I~.VS$ ~ ~ ~~~
ON ~•I DE AGO ~.S W fiERE M~`~
/S DL~FP~,~
2 More species are recommended.
2 More species are recommended. I~0 ROOD FoR
2 More species are recommended. /~DDl~lati'R-L S'~E~~
Y (Y or N)
Y (Y or N)
130 ft
N (Y or N) Show how flow is evenly distributed.~D~SGffI~~(T~• ~GOWS
Td ~lEW A4~/DETF~T/O/l &1-S.~• PR/nsH~'~ D/S=
Y (Y or N) C'~GE /s' 7~r~9uC~/ 3 "!'/pE u!/ /+~N•x
C'.~S of o• 22 . En/~'.~ls~ niss~lq~l~
Y (Y or N) T~,QOVG</ R/p-~RP A~~)
Y (Y or N) OK
Y (Y or N) OK
0.94 ft/sec OK
N (Y or N)
N (Y or N) OK
Y (Y or N) OK
X
OK
Form SW401-Bioretention-Rev.1 Parts I and II. Design Summary, Page 2 of 2

Permit No:
(to be assigned by DWQ)
IIh REQUIRED ITEMS CHECKLIST
Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will
result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to
indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a
requirement has not been met, attach justification.
Pagel Plan
Initials Sheet No.
_~ 1. Plans (1" - 50' or larger) of the entire site showing:
- Design at ultimate build-out,
-Off-site drainage (if applicable),
-Delineated drainage basins (include Rational C coefficient per basin),
-Cell dimensions,
-Pretreatment system,
-High flow bypass system,
-Maintenance access,
-Recorded drainage easement and public right of way (ROW),
-Clean out pipe locations,
-Overflow device, and
-Boundaries of drainage easement.
2. Plan details (1" = 30' or larger) for the bioretention cell showing:
-Cell dimensions
-Pretreatment system,
-High flow bypass system,
-Maintenance access,
-Recorded drainage easement and public right of way (ROW),
-Design at ultimate build-out,
-Off-site drainage (if applicable),
-Clean out pipe locations,
-Overflow device, and
-Boundaries of drainage easement.
~~ 3. Section view of the bioretention cell (1" = 20' or larger) showing:
-Side slopes, 3:1 or lower
- Underdrain system (if applicable), and
- Bioretention cell layers (ground level and slope, pre-treatment, ponding depth, mulch depth, fill media
depth, washed sand, filter fabric (or choking stone if applicable), #57 stone, underdrains (if applicable),
SHWT level(s), and overflow structure]
-+-~ L
L~N~~+iN
(~~)

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Form SW401-Bioretenlion- Rev.1
A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. The
results of the soils report must be verified in the field by DWQ, by completing & submitting the soils
investigation request form. County soil maps are not an acceptable source of soils information. All
elevations shall be in feet mean sea level (fmsl). Results of soils tests of both the planting soil and the in
situ soil must include:
-Soil permeability,
- Soil composition (% sand, % fines, % organic), and
- P-index.
A detailed planting plan (1" = 20' or larger) prepared by a qualified individual showing:
- A variety of suitable species,
-Sizes, spacing and locations of plantings,
-Total quantity of each type of plant specified,
- A planting detail,
-The source nursery for the plants, and
-Fertilizer and watering requirements to establish vegetation.
5
6. An assurance that the installed system will meet design specifications upon initial operation once the `
project is complete and the entire drainage area is stabilized. (1~ER CdN~I/GTIO~/C~~~A~J
7. A construction sequence that shows how the bioretention cell will be protected from sediment until the
entire drainage area is stabilized. (~/LTFEn/CE PRoY/~~ AT'"/NL~r~
8. The supporting calculations (including underdrain calculations, if applicable). C!}777NCt1'~~~
9. A copy of the signed and notarized inspection and maintenance (I&M) agreement. ~A'lrflG/~'EV,
10. A copy of the deed restriction. ~ %o wn/ QWNE19 PRO/'~R'T~ 1CO~Q p~M/' .~770r~ ONC.~~
Part III, Page 1 of 1

4
Nitrogen Loading Estimation
Nitrogen Export from proposed impervious area within Buffer -Pre-development:

Type of Land Cover
Area
ac
TN Export Coef.
Ibs/ac/ r TN
Export
Ibs/ r
Permanentl Protected Undisturbed 0.023 0.6 0.014
Permanentl Protected Mana ed O en S ace 0.000 1.2 0.000
Im envious Surface 0.000 21.2 0.000
Total 0.023 0.014
Total N-loading = 0.0141bs/yr - 0.023 acres = 0.61 lbs/ac/yr
Nitrogen Export from impervious area within Buffer -Post-development:

Type of Land Cover
Area
ac
TN Export Coef.
Ibs/ac/ r TN
Export
Ibs/ r
Permanentl Protected Undisturbed 0.000 0.6 0.000
Permanentl Protected Mana ed O en S ace 0.015 1.2 0.018
Im envious Surface 0.008 21.2 0.170
Total 0.023 0.188
Total N-loading = 0.188 lbs/yr _ 0.023 acres = 8.171bs/ac/yr
A BMP must be installed to treat this loading that allows for a reduction of at least 30%.
A bioretention basin is the BMP of choice which per the state BMP manual is credited for
a 35% removal of TN. Nitrogen load after BMP treatment is 5.31 lbs/ac/yr.
Note that an offset payment has already been made to the NCEEP for the N-loading over
the entire site. This was a separate permitting process in accordance with the Neuse
Stormwater Rules.

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THE WOOTEN COMPANY, EZO N. BQYLAN AVENUE, RALEIGH, NC 27603
PHQNE:919.828.0531 FAX: [phone]

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PHONE: 919.828.Q531 FAX' 919.834.3589

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PNONE:919.828.0531 FAX: [phone]

E °~ement
PROGRAM
November 20, 2007
Ken Schuster
Town of Cary
316 N, Academy Street
Cary, NC 2751 l
01 -'DOI`1 V~
.~ r~~ ~~ ~ ~~w~ ~
(~~
~l~~ L ~ 2007
pEi~~. - WATs~Ft t11JALIlY
Y1IET1ltND4,~a~sa 5T0!i!N!.~'ATER.3iZZ,M1CH
Expiration of Acceptance: May 20, 2008
Project: Terrington Pump Station and Force Main County: WAKE
The purpose of this letter is to notify you that the North Carolina Ecosystem Enhancement Program (NCEEP) is willing to
accept payment for impacts associated with the above referenced project. Please note that this decision does not assure that
the payment will be approved by the permit issuing agencies as mitigation for project impacts. It is the responsibility of the
applicant to contact these agencies to determine if payment to the NCEEP will be approved.
This acceptance is valid for six months from the date of this letter and is not transferable. If we have not received a copy of
the issued 404 Permit1401 Certification/CAMA permit within this time frame, this acceptance will expire. It is the
applicant's responsibility to send copies of the permits to NCEEP. Once NCEEP receives a copy of the permits} an invoice
will be issued based on the required mitigation in that permit and payment must be made prior to conducting the authorized
work. The amount of the In Lieu Fee to be paid to NCEEP by an applicant is calculated based upon the Fee Schedule and
policies listed at www.nceep.net.
Based on the information supplied by you the impacts that may require compensatory mitigation are summarized in the
ollowin table.
NEUSE Stream (feet) Wetlands (acres) Buffer I Buffer II
03020201 (Sq. Ft.) (Sq. Ft.)
Cold Cool Warm Ri arian Non-Ri arian Coastal Marsh
Impacts 0 0 0 0 0 0 0 375
Credits 0 0 0 0 0 0 0 563
Upon receipt of payment, EEP will take responsibility for providing the compensatory mitigation. If the regulatory agencies
require mitigation credits greater than indicated above, and the applicant wants NCEEP to be responsible for the additional
mitigation, the applicant will need to submit a mitigation request to NCEEP for approval prior to permit issuance. The
mitigation will be performed in accordance with the Memorandum of Understanding between the N. C. Department of
Environment and Natural Resources and the U. S. Army Corps of Engineers dated November 4, 1948.
If you have any questions or need additional information, please contact Kelly Williams at [phone].
Sincerely, /~ `
~.
Will D. Gilmore, PE ~Uf
Dvector
cc: Cyndi Karoly, NCDWQ Wetlands/401 Unit
Amy Chapman, NCDWQ- Wetlands/401 Unit
Brian Johnson, agent (email)
File
Restor%t29... ~ ... Pao Ou.~ Stag ~~
~ut~
North Carolina Ecosystem Enhancement Program, 1652 Mail Service Center, Raleigh, NC 27699-1652 / 919-715-0476 ! www.nceep.net