20041764 Ver 2_More Info Received_20070621

Shiloh Crossing 04-1764v3
Subject: Shiloh Crossing 04-1764v3
From: Annette Lucas <[e-mail]>
Date: Thu, 21 Jun 2007 15:05:14 -0400
To: [e-mail]
CC: Cyndi Karoly <[e-mail]>, Ian McMillan <[e-mail]>, John
Dorney <[e-mail]>
Todd,
I got your phone message about Shiloh Crossing. I looked in the file and saw the
surface area data for Wetland A - it looks fine and I will accept it. (In the
future though please include it on the worksheet.) Also, I will accept the
slightly under 10 acre drainage area for Wetland B.
When John Dorney returns to the office, Ian or I will ask him about the issue of
the Right of Way runoff going directly to the level spreader. If this was agreed to
in apre-application meeting, then we will be able to approve the whole project. If
not, this issue will still need to be addressed.
We'll be in touch once we hear from John.
Annette
Annette Lucas <annette.lucas(a,ncmail.net>
Environmental Engineer III
401 Wetlands Oversight/Express Unit
NC Division of Water Quality
1 of 1 6/26/2007 12:52 PM

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Duerr, Craig ~0 ~
From: Duerr, Craig
Sent: Friday, September 02, 2005 12:01 PM
To: '[e-mail];'[e-mail]'; St John, Todd; '[e-mail]'
Cc: Reed, Beth; Webster, Norton; '[e-mail]'
Subject: Shiloh Crossing DWQ Meeting
Debbie/Mike/Sam,
Thanks for taking the time to meet with us Tuesday morning on August 31st to discuss the proposed Shiloh Crossing
retail shopping center development at Highways 54 and I-540 in Morrisville/Durham. !n general, we understand that DWQ
accepts the proposed roadway alignment and our efforts to minimize stream impacts with reducing the design speed to
allow for improved geometry and narrowing the pavement section to 2-lanes at each crossing. For the pending 4011404
permits later this fall, we will provide the necessary detail for rip-rap dissipaters at the stream crossings, sideslope
stabilization, and culvert type. As discussed, we are considering a Conspan type structure to minimize stream impacts if
site conditions are favorable to potential issues with erosion and settlement.
Also, we appreciate the opportunity to discuss the proposed BMPs to manage stormwater run-off from 100% of the
developed portions of the site and the alternative design for a level spreader with bypass to provide diffuse flow.through
the buffers in compliance with Riparian Area Protection Rules for the Neuse. As discussed and confirmed with ~DWQ's
John Dorney, the application would be limited to portions of the public roadway only due to difficult topography and
shallow bedrock that will impact the depth of storm sewer lines and wet detention basin.
We again appreciate your time and will touch base with Eric moving forward with further questions within his jurisdiction.
":raig M. Duerr
.:imley-Horn & Associates, Inc.
3001 Weston Parkway
Cary, NC 27513
Tel # [phone]
Fax # [phone]
craig~ uerrC~kimiev-horn.com
From: Sam Aghimien [mailto:[e-mail]]
Sent: Tuesday, August 16, 2005 1:10 PM
70: St John, Todd
Cc: [e-mail]; mike.horan@ncmail net; Duerr, Craig; Reed, Beth; Webster, Norton
Subject: Re: Pre-App meeting and possible site visit
Todd. tJohnCcr~lcimley-horn.com wrote:
Debbie, Mike, and Sam,
Lets go ahead and say...
Wednesday August 31, at 10:00 AM... ???
Thanks,
Todd
-----Original Message------
From: Debbie Edwards [mailto:debbie.edwards@ncmail .net]
Sent: Monday, August OB, 2005 9:06 AM
To; St John, Todd
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9/ 16/2005

Page 2 of 2
Subject: Re: Pre-App meeting and possible site visit
That week will work for me as well, I would prefer to meet here at
Crabtree Blvd though.
debbie
[e-mail] wrote:
Hi Debbie, Sam, and Mike,
I have a site that is off Hwy 54 where 540 will cross that straddles
Durham and Wake Counties and drains to Stirrup Iron Creek. Debbie, I
believe you already visited this site last year with Kevin Martin and
made the buffer calls. Kevin got Cyndi to come out there later and
throw out a little tiny portion of stream afterwards...
Anyway, the site is now proposed to be developed and we are in the
process of site design. I have worked with our folks to minimize
impacts as best we can. But, I want to have a pre-application meeting
to go over our proposal since it is a very large commercial site.
Fortunately, the 404/401/Buffer permitting is not the critical path,
time-wise {for once), and since we have that luxury, i thought it
would be good to take advantage and develop consensus ahead of time...
{imagine that for a concept!!!)
So, I was going to try to set up a time for us to meet. If you would
like we could meet onsite or at Crabtree...
How about the week of August 29th to Sept 2nd7
thanks,
todd
Todd, that is okay with me.
Sam
9/16/205

Michael F. Easley
Governor
~_
G
William G. Ross, Jr., Secretary
Department of Environment and Natural Resources
Kerr T. Stevens
Division of Water Quality
Draft Level Spreader Design Options Version 1.0 October 10, 2001
Using Level Spreaders to Provide Diffuse Flow Through Buffers for Compliance with Riparian Area Protection Rules
Level spreaders are one means of providing diffuse flow through protected buffers. It is always preferable to not
concentrate stormwater initially and provide as many outfalls as possible. This can reduce or even eliminate the need for
engineered devices to provide diffuse flow. However, this is not feasible in many cases. Some buffer protection rules such
as the Neuse, Catawba, and Tar-Pamlico Riparian Area Protection Rules do not allow direct discharges of stormwater
through the protected buffers. However, it is "allowable" with written approval from the DWQ to provide best management
practices (BMPs) that remove the nutrients or pollutants in question in order to discharge directly through the buffer.
These measures could include the use• of the buffer itself as a forested filter strip, for instance, to remove the desired
substances. In addition to providing diffuse flow, level spreaders can be used to distribute flow into filter strips.
There are certain criteria that apply to every design that utilizes level spreaders to provide diffuse flow:
1) The entire system must safely pass a 10 year storm event without failing or causing erosion, gullies or rills.
2} The design of the level spreader must take into consideration site specific conditions such as topography, vegetative
cover, soil and other geologic conditions. If diffused flow is not attainable based on site conditions they should not be
used. (i.e. the slope of the natural ground away from or parallel to the level spreader should be relatively smooth in
the direction toward the stream so that the flow will not reconcentrate.)
3) Level spreaders should have a minimum length of ten fee# and an absolute, maximum length of 300 feet.
4) It is always easier to keep flow distributed than to redistribute it after collection.
5) The type and amount of vegetative ground cover must also be considered.
6) Level spreaders must be level.
Leval Spreader Design Options:
Conventional {evel spreader design option where entire discharge is passed through the level spreader with
no bypass conveyance for larger storms:
• For grass or thick ground cover vegetation:
i)13 feet of level spreader for every 1 cfs flow (Based on Q10 discharge)
ii) maximum length of 300 feet per level spreader
iii) Slopes of 8% or less from level spreader to top of stream bank
• For forested areas with little or no ground cover vegetation:
i) 100 feet of level spreader for every 1 cfs flow (based on Q10 discharge}
ii) maximum length of 300 feet per level spreader
iii) slopes of 6% or less from level spreader to top of stream bank
Another conventional level spreader design technique that can be used to accommodate steeper slopes where grading is
allowed or exempt in zone 2 of protected buffers is to provide level spreaders in series as follows:
• Can be used on slopes of up to 15% for forested areas and 25% for grass or thick ground cover
• Structural level spreader just outside of zone 2 followed by a grassed berm level spreader just outside of zone 1
North Carolina Division of Water Quality, 401 Wetlands Certification Unit,
1650 Mail Service Center, Raleigh, NC 27699-1650 (Mailing Address}
2321 Crabtree Blvd., Raleigh, NC 27604-2260 {Location)
919-733-1786 (phone), 919-T33-6693 (fax), htlo://h2o.enr.state.nc.us/ncwetlands/

Page2of2
• Maximum Q10 discharge of 1 cfs per 100 feel of level spreader for forested areas and 1 cfs per 13 feet of level
spreader for grass or thick ground cover
In some instances, because of topography, the size and imperviousness of the drainage area, or other site constraints,
conventional level spreader designs are not appropriate. However, there are alternative designs, like the ones fisted
below, that would allow a level spreader to function properly by bypassing the larger discharge events. This is based on
the assumption used in designing most water quality BMPs that the "first flush" of stormwater discharge contains the
most substances of concern. These other alternatives are "allowable (require written approval from DWQ)" for protected
buffers in the Neuse, Tar-Pamlico and Catawba basins, but would not be allowable in protected buffers of the Randleman
watershed.
Level spreader with bypass for larger drainage areas that require. 85% TSS removal or where lateral constraints limit the
level spreader length severely:
• Dry detention basin designed per NCDENR Stormwater BMP Manual' sized to detain 1" rain and release it over 2-5
days" through a level spreader.
• Level spreader length based on the maximum release rate discharge
• Discharges from greater than a 1" rain can be bypassed via an appropriate conveyance such as a grassed swale {rip
rap lined ditch or pipe may be used if necessary)
• Maximum discharge of 1 cfs per 100 feet of level spreader for forested areas and 1 cfs per 13 feet of level spreader
for grass or thick ground cover
*( in order to meet 85%TSS Removal criteria}
Another bypass alternative can be used that would not be considered to remove 85°~ TSS:
• Detention basin such as a type B silt basin preceding the level spreader
• Level spreader {ength based on the 1" per hour intensity storm,
• A system designed to bypass the greater than 1" in per hour intensity storm through an appropriate conveyance such
as a grassed swale (rip rap lined ditch or pipe may be used if necessary}
• Maximum discharge of 1 cfs per 100 feet of level spreader for forested areas and 1 cfs per 13 feet of level spreader
for grass or thick ground cover
Yet another design that can be used in very specific areas with virtually flat slopes is a Preformed Scour Hole with a Level
Spreader•Apran (typical detail attached):
• Discharge area must have virtually flat slopes such as those in flood plains or we#lands
• Must be located outside of zone 2
• B = 3 x discharge pipe size for pipes of either 15 or 18 inches B= base width (see detail)
• Maximum allowable discharge (Q10) of 6 cfs fora 15 inch pipe and 10 cfs for an 18 inch pipe
• Minimum apron width of 4 feet.
Any of the above options will be considered acceptable if designed in accordance with the outlined criteria. Please keep in
mind that some of the above practices may still require written approval, for instance when a direct bypass discharge is
proposed through a protected buffer in the Neuse or Tar-Pamlico River Basin.

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DWQ Project No. ~~~ ~r ~ t ~~\I , d
DIVISION OFWATER QUALITY - 401 EXTENDED DETENTION {and POCKET) WETLAND WORKSHEET
PROJECT INFORMATEON (please complete the following information):
Project Name: Slfu-o~ C¢ossi~G
Contact Person: Jssa..a Kf,a~ ~r~
For projects with multiple basins, specify which basin
Phone Number: {Rlq) ti53 - 24 ~S
worksheet applies to: Ex•EeNO~o ,n7FZU.av A
Pemtanent Pool Elevation ~5~1.0o ft. {elevation of the orifice invert out)
Temporary Pool Elevation 3~.ro~ ft. {elevation of the outlet structure invert in)

Permanent Pool Surface Area 71.si9 sq. ft. (water surface area at permanent pool elevafwn}
Drainage Area y1.3s ac. (on-site and off-site drainage to the basin)
Impervious Area 3~~I~ ac. (on-site and off-site drainage to the basin)
Forebay Surface Area W7.o4°- sq. ft. (at permanent pool elevation approximately 15°~)'
Marsh 0"-9" Surface Area Zy, 9.1 S sq. ft, (at permanent pool elevation approximately 35%)'
Marsh 9"-18" Surface Area ,-„ 2fr.o 0 8 Sq. ft. (at permanent pool eleva#ion approximately 35%)'
Micro Pool Surface Area N,seo sq. ft. (at permanent pool elevation approximately 15~°)'

Temporary Fool Volume X49. pee cu. ft. (volume detained on fop of the permanent pool)

SA1DA used 3.5R (surface area to drainage area ratio)'
Diameter of Orifice N.~ in. (draw down orifice diameter)
II. REQUIRED REMS CHECKLIST
Initial in the space- provided to indicate the following design requirements have been met and supporting documentation is attached. If a
requirement hes not been met, attach an explanation of why. At a minimum, a complete stormwater management plan submittal includes
a worksheet for each BMP, design cak:ulations, plans and specifications showing all $MPs and outlet structure detais, a detailed
drainage plan and. a fully executed operation and maintenance agreement. An incomplete submittal package will result in a request for
additional information and wil! substantiaEly delay final review and approval of the project
Apolicants initials
JPK The temporary pool controls runoff from the 1 inch rain.
. _,_,, t PK The basin side slopes are no steeper than 3:1.
JPK A planting plan for the marsh areas wiUi plant species and densities is provided.
JPK Vegetation above the perrrtanent pool elevation is specified.
J PK An emergency drain is provided to drain the basin.
J P K The temporary pool draws down in 2 to 5 days.
J P K Sediment storage is provided in the permanent pool:
JPtC A sediment disposal area is provided.
J PK Access Is provided for maintenance.
A site specific, signed and notarized operation and maintenance agreement is provided.
JPK The drainage area (including any offsite area) is delineated on a site plan.
_I PtC Access is provided for maintenance.
~i P K Plan details for the wettand are provided.
Plan details for the inset and outlet are provided.
A site specific operation and maintenance agreement, signed and notarized by the responsible party is provided (see
http:llh2o.ehnr.state.nc.uslncwetiands/oandm.doc}.
' Pocket Wetlands have different design parameters and are only assumed to remove 35% TSS -See pp.19and 20 of the NC DENR
Slormwafer BMP Manual, April 1999.10°io open water, 50% high marsh, 40% low marsh.