20052167 Ver 2_Fax_20060703

Jul 03 2006 2:27PM
HP LRSERJET FRX
KE
KELLER ENYIRONMEN7AL
ENVIRONMENTAL GGNSULTANTS
124 Waiters Way
Youngsville, NC 27596
Phone: [phone]
Fax: [phone]
919-554-3836
p.1
E-mail: [e-mail]
Please Deliver this FAX to:
Name: Staff Date: 713/2006
Comnany= DWQ 401 Wetlands Unit Fax Number: 733-6893
From• Jay Keller Pages - induding this page: 5 ___
Comments: We have addressed the level spreader concerns at Winston Ridge Subdivision. If
there are any questions during your review, please call or email me immediately.
The information contained in this FAX message is privileged and confidential information intended
only for the use of the individual or entity named above,
If you are not the intended recipient, you are hereby notified that any reading, dissemination,
distribution or photocopying of this communication is strictly prohibited.
If you have received this communication in error, please immediately notify us by telephone and
return the original message to us at the above address via U.S. mail. Thank you.
JUL-3-2006 MON 13:16 TEL: [phone] NAME:DWQ-WETLANDS P. 1

Jul 03 2006 2:27PM HP LRSERJET FRX 919-554-3836 p.2 _
June 26, 200fi
Cyndi Karoly
NC Division of Water Quality
401 Wetlands WQ Certification Unii
1fi50 Mail Service Center
Raleigh, North Carolina 27699-1650
Re: Winston Ridge Subdivision
DWQ Project # 05-2167 Franklin County
Franklin County, North Carolina
Dear Ms. Karoly:
We are submitting the additional information requested from written
correspondence on June 26, 2006. We are requesting for NC Division of Water
Quality (NCDWQ) written approval under Section 401, Clean Water Act, 33 USC
1344. This will assist incompliance with Water Quality Certification {WQC) 3402 and
it's accompanying Nationwide Permit (NWP} 39. We have addressed your included
written comments in the following paragraphs.
1. Level Spreaders -Earthen Isvel spreaders are not an acceptable
diffuse flow structure. Please revise your plans showing an
approvable level spreader device.
According to the current DWQ October 10, 2001 "Draft Level Spreader
Design Options Version 1.O,n the proposed earthen level spreaders meet all of the
criteria outlined. The engineering plans submitted on April 21 clearly show the
materials and specifications for each level spreader on Drawing C3 (Storm Drainage
and Erosion Control Plan). Immediately after construction, the level spreaders will
be seeded with permanent erosion control seed to facilitate stabilization. According
to the previously signed and submitted "Operation and Maintenance Agreement" for
the on-site storrnwater structures, the level spreaders will be regularly monitored and
maintained to ensure sheet flow into the Neuse River Buffer areas.
Additionally, according to rules [15A NCAC 2H .0507 {A}], if final action is not
taken within fi0 days, the Certification is waived unless DWQ has objected in writing to
your application. The above level spreader information was previously submitted.
Therefore, the 401 Water G2uality Certification's time limit for final action has passed.
JUL-3-2006 MON 13:17 TEL: [phone] NAME:DWQ-WETLANDS P. 2

Jul 03 2006 2:27PM HP LRSERJET FRX 919-554-3836 p.3
DWQ 401 Certification &
Neuse R. Buffer Rules Re-Submittal
Winston Ridge Subdivision
June 26, 200b
Page 2 of 2
If you should have questions or require additional clarification please feel free
to contact me at [phone] or email: kellerenviroCc~earthlink.net.
Sincerely,
Keller Environmental, LLC
,~
Jay Keller
Principal
Cc: Jeff Crisp, PE
Attachments:
October 10, 2001 "Draft Level Spreader Design Options Version 1.0."
JUL-3-2006 MON 13:17 TEL: [phone] NAME:DWQ-WETLANDS P. 3

Jul 03 2006 2:27PM HP LRSERJET FRX
919-554-3836 p.4
Michael F. Easley
Governor
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.t)
October 10, 2001
lJsing Levef Spreaders to Provide Diffuse Flow Through Buffers for Compliance wish Riparian Area Protection Rules
Level spreaders are one means of providing diffuse- flow through protected buffers. It is always preferable to not
concentra#e 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-F~amlioo Riparian Area Protection Rules do not allow direct discharges of stormwater
through the protected buffers. However, it is "allowable' with written approval from the DWO to provide best management
practices (6MPs) 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 iorested finer scrip, 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 util'¢es 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 feet 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.
Level Spreader Design Options:
Conventional level 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 teat of level spreader for every 1 cfs flow (Based on Q10 discharge)
ii} maximum length of 300 feet per level spreader
iii) Sbpes of 8% or less from level spreader to top of stream bank
• Forforested areas with little or no ground cover vegetation:
i) 100 feet of level spreader for every 1 cis 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°k for forested areas and 25% for grass or thick ground cover
• Structural level spreader just outside of zone Z followed by a grassed berm level spreader just outside of zone 1
North Carolina Division of Water Quality, 401 Wetlands Ceriificalion Unit,
1650 Mall Service Center, Raleigh. NC 27688-1650 {Mailing Address)
2321 Crabtree Blvd., Raleigh, NC 27604-2260 (Location;
919-7331786 (phone), 919-733-6893 (fax), htto~l/h2o enr state rc.uslncwetlands/
JUL-3-2D06 MON 13:17 TEL:[phone] NAME:DWQ-WETLANDS P. 4

Jul 03 2006 2:27PM HP LRSERJET FRX 919-554-3836 p.5
Page 2 of 2
Maximum Q10 discharge of 1 cfs per 100 feet of level spreader for forested areas and 1 cis per 13 feet of level
spreader for grass or thick ground cover
In some instances, because of topography, the size and impeNiousness of the drainage area, or other site oonsiraints,
conventional level spreader designs are not appropriate. However, there are altemative designs, like the ones listed
below, that would albw 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°1o 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 apprapriate 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 length based on the 1" per hour intensity storm
• A system designed to bypass the greater than 1" in per hour intensity storm #hrough 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 Apron (typical detail attached):
• Discharge area must have virtually flat slopes such as those in flood plains or wetlands
• 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 B 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 arTar-Pamlico River Basin.
JUL-3-2016 MON 13:18 TEL:[phone] NAME:DWQ-WETLANDS P. 5