20050675 Ver 3_More Info Received_20071207

Blackburn Consulting Engineering
234 East Main Street
Clayton, NC 27520
Phone: [phone]
Fax: [phone]
COVER SHEET
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To: North Carolina Division of Water Quality
Attention: Annette Lucas
Date: December 7, 2007
From: Danny Blackburn
Subject: Moss Creek Village Business Park DWQ Project #OS-0675, Ver.3
Johnston County
Message:
We received a letter from you dated November 15, 2007, regarding the required Diffuse
Flow Plan for the referenced project. You rejected the previously submitted plan noting
that the filter strip slope exceeded the allowable slope. I discussed this with you by
phone on November 29, 2007. We discussed the possibility of moving the existing
sidewalk and proposed level spreader further from the stream in order to provide a full
50' buffer strip with flatter slopes. This submittal is consistent with that discussion.
The existing sidewalk is being moved eastward away from the stream allowing the
proposed level spreader to be built to current BMP standards. By moving the sidewalk,
we are able to provide a forebay and 50' of filter strip with maximum slope less than the
allowable 8%.
Some of the lots tributary to this device have already been sold. Since this BMP was not
designed prior to the transfer of ownership, this BMP will not be the responsibility of any
"homeowner's association" but will be owned and maintained by the owner of lot B-1 on
which it is constructed. This is noted on sheet 2 of the plan. Per the checklist, an
"Inspection and Maintenance Agreement" is attached.
Resubmitted for your approval are 5 copies of the following:
1) Design plans
2) Drainage calculations
3) Inspection and Maintenance Agreement
4) Level Spreader supplement
5) Required items checklist
6) Photographs of filter strip
Thank you,
~~~v

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STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
LEVEL SPREADER, FILTER STRIP AND RESTORED RIPARIAN BUFFER SUPPLEMENT
' ~t~ur~~f~~r~s Ctt~ck6~t (Pa This form must ba filled out nnnted and submitted.
~ ~' it~lll) rftust be p~lrit~d, i~JIQd,o„„~ and;~llbmlttad,~~png h al)ak9~`~gt~~t7~ti:
h PROJECT INFORMATION
Project name Moss Creek Business Park
Contact name Daniel W. Blackburn
Phone number 553.2900
Date December 5, 2007
Drainage area number ONLY 1
IL DESIGN INF'OaMATION
For Level Spreaders Receiving Flow From a BMP
Type of BMP
Drawdown flow from the BMP cfs
For Level Spreaders Receiving Flow from the Drainage Area

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Draina a area
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Impervious surface area 61, 680 ft2 :;.
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Percent impervious 0.80 zl C _ (• s~ ? j~~•(
Rational C coefficient 0.76 ~' .-
Peak flow from the 1 in/hr storm 1.345179063 cfs
Time of concentration min ~,~,.p ~rrA,v~TFP.9R;At'eGt~
WEitAND~ ~' ~ ~ 0
Rainfall intensity, 10-yr storm 7.38 inlhr
Peak flow from the 10-yr storm 9.927421488 cfs
Where Does the Level Spreader Discharge?
To a bioretention cell? n (Y or N)
To a wetland? n (Y or N)
To a filter strip or riparian buffer? y (Y or N) Please complete filter strip characterization below.
Other (specify)
Filter Strip or Riparian Buffer Characterization (if applicable)
Width of grass 15 ft
Width of dense ground cover 35 ft
Width of wooded vegetation 0 ft
Total width 50 ft
Slope (from level lip to to top of bank) 6.6
Are any draws present? n (Y or N) OK
Level Spreader Design
Forebay surface area 150 sq ft OK
Feet of level lip needed per cfs 13 ft/cfs
Answer 'Y" to one of the following:
Length based on the 1 inlhr storm? N (Y or N)
Length based on the 10-yr, 24-hr storm? Y (Y or N)
Length based on the BMP discharge rate? N (Y or N)
Design flow 9.93 cfs
Is a bypass device provided? N (Y or N) A bypass device is not needed.

Form SW401-Level Spreader, Filter Strip, Restored Riparian Buffer-Rev.2 Parts I. and II. Design Summary, page 1 of 2

Length of the level lip
Are level spreaders in series?
Bypass Channel Design (if applicable)
Does the bypass discharge through a wetland?
Does the channel enter the stream at an angle?
Dimensions of the channel (see diagram below):
M
B
W
Y
Peak velocity in the channel during the 10-yr, 24-hr storm
Channel lining material
t ~-----------
M
130 ft Level spreader length OK.
N (Y or N)
(Y or N) Do not complete this section of the worksheet.
Do not complete this section of the worksheet.
Do not complete this section of the worksheet.
ft Do not complete this section of the worksheet.
ft Do not complete this section of the worksheet.
ft Do not complete this section of the worksheet.
ft Do not complete this section of the worksheet.
cfs Do not complete this section of the worksheet.
Do not complete this section of the worksheet.
Y
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Form SW401-Level Spreader, Filter Strip, Restored Riparian BuNer-Rev.2 Parts I. and II. Design Summary, page 2 of 2

lll. REQUIRED {TENS 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.
Page! Plan
Initials Sheet No.
Qw.~ ~ 1. Plans (1" - 50' or larger) of the entire site showing:
/- Design at ultimate build-out,
Nlp -Off-site drainage (if applicable),
/- Delineated drainage basins (include Rational C coefficient per basin),
/ -Forebay (if applicable),
N/A -High flow bypass system,
,.~ -Maintenance access,
/ -Recorded drainage easement and public right of way (ROW), and
-Boundaries of drainage easement.
pug 6 ~ 2. Plan details (1" = 30' or larger) for the level spreader showing:
/- Forebay (if applicable),
pl~~ High flow bypass system,
~/= One foot topo lines between the level lip and top of stream bank,
/-Recorded drainage easement, and
/ -Design at ultimate build-out.
~y,d 2- 3. Section view of the level spreader (1" = 20' or larger) showing:
Nf 14 - Underdrain system (if applicable),
~/- Level lip,
a~ - Upslope channel, and
/- Downslope filter fabric.
4. Adate-stamped photograph of the filter strip that clearly shows the type of vegetation that is present.
~~~+ ~ ~ 5. 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.
nn
W'J 2" 6. A construction sequence that shows how the level spreader will be protected from sediment until the entire
drainage area is stabilized.
y w / 7. The supporting calculations.
8. A copy of the signed and notarized inspection and maintenance (I&M) agreement.
~~ ~ 9. A copy of the deed restriction. _ ~~ ~ ~~~ L~-~2

Form SW401-Level Spreader, Filter Strip, Restored Riparian Buffer-Rev.2 Part III, page 1 of 1

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Filter Strip, Restored Riparian Buffer and Level Spreader
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 maintenance procedures:
- Immediately after the filter strip is established, any newly planted vegetation
will be watered twice weekly if needed until the plants become established
(commonly six weeks).
- Once a year, the filter strip will be reseeded to maintain a dense growth of
vegetation
- Stable groundcover will be maintained in the drainage area to reduce the
sediment load to the vegetation.
- Two to three times a year, grass filter strips will be mowed and the clippings
harvested to promote the growth of thick vegetation with optimum pollutant
removal efficiency. Turf grass should not be cut shorter than 3 to 5 inches and
may be allowed to grow as tall as 12 inches depending on aesthetic requirements
(NIPC, 1993). Forested filter strips do not require this type of maintenance.
- Once a year, the soil will be aerated if necessary.
- Once a year, soil pH will be tested and lime will be added if necessary.
After the filter strip is established, it will be inspected quarterly and within 24 hours
after every storm event greater than 1.0 inch (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 roblem: How I will remediate the roblem:
The entire filter strip Trash/debris is present. Remove the trash/debris.
s stem
flow splitter device
(if ap 'able) ow splitter device is
l clog the conveyance and dispose
~
c
o ed. of are invent off-site.
"I'he flow splitter e is Make any nec repairs or
damaged. replace if damage is to for
repa i r_

BMP element: Potential roblem: How I will remediate the roblem:
The Swale and the level The swale is clogged with Remove the sediment and dispose
lip sediment. of it off-site.
The level lip is cracked, Repair or replace lip.
settled, undercut, eroded or
otherwise dama ed.
There is erosion around the Regrade the soil to create a berm
end of the level spreader t}lat that is higher than the level lip, and
shows stormwater has then plant a ground cover and
bypassed it. water until it is established. Provide
lime and aone-time fertilizer
a lication.
"frees or shrubs have begun Remove them.
to grow on the swale or just
downslo e of the level li .
e bypass channel reas of bare soil and/or
' rade the soil if necessary to
ero
e gullies have formed, remo the gully, and then
reestablis o er erosion control.
Turf reinforc ent is Study the site to if a larger
damaged or ripap ' rolling bypass channel is nee (enlarge if
downhill. necessary). After this, rees lish
the erosion control material.
The filter strip Grass is too short or too long Maintain grass at a height of
if a licable . a roximatel three to six inches.
Areas of bare soil and/or Regrade the soil if necessary to
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.
Sediment is building up on Remove the sediment and
the filter strip. restabilize the soil with vegetation if
necessary. Provide lime and a one-
time fertilizer a lication.
Plants are desiccated. Provide additional irrigation and
fertilizer as needed.
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 a lication.
Nuisance vegetation is Remove vegetation by hand if
choking out desirable species. possible. If pesticide is used, do not
allow it to get into the receiving
water.
The receiving water F.,rosion or other signs of Contact the NC Division of Water
damage have occurred at the Quality local Regional Office, or the
outlet. 40] Oversi ht Unit at 919-733-1786.

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.
Print name: William R. O'Neal V
Title: Owner
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.
I, ~~~-~-C~t.C.~~e.~ 1'~ . ~GZ~~QI..,~, , a Notary Public for the State of
~~4~~ ~~2.~-~'K~'ounty of __ , do hereby certify that
~4'~U d ~ ~ ~ personally appeared before me this ~` _~
day of ,o~, and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
Address: 5 Nicklaus Way Clayton, NC 27520
/Q,~NE N. M,~~~.,
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My commission expires ~-a ~~ ~
Date: / U ' / 5 ' ~ "/

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