20061421 Ver 1_Stormwater Info_20060914

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STORM DRAINAGE
CALCULATIONS
FOR
MIDDLE CREEK COMMONS
a
PROJECT NO. 06-4013 ~~`~ ~ ~ '~~'~~
a •;
AUGUST 2006
JOHNSTON COUNTY
NORTH CAROLINA
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Prepared By:
Chas. H. Sells, Inc. ag ~~~`~€~~~ o
15401 1Meston Parkway, Suite 100 ~``~~~ ~~°`~~~~°~ ~°~~~~~
Cary, NC 27513 ~~~~~~~~~ ~ ~~r ~ t~~
Project Manager: Donald A. Sever, P.E.

CHAS. H. SELLS, INC.
TABLE OF CONTENTS
MIDDLE CREEK
COMMONS
General Information
Impervious Area
Peak Runoff Reduction
Existing Drainage ways
Nitrogen Calculations
Pre and Post Development Flows
Stormwater Drainage Calculations
BMP Design Calculations
Velocity Dissipator Calculations
Reservoir Watershed Protection Impoundment
Maintenance Agreement
Qperations and Maintenance Manua!

Project Name: Middle Creek Commons Shopping Center
Location: NC 42 /NC 50 Southwest intersection. Located approximately 0.5 mile
east of the Wake County / Johnston County line.
Developer: Regency Centers LLP
101 Maynard Crossing Center
Cary, NC 27513
Consultant: Chas H. Sells, INC.
15401 Weston Parkway, Suite 100
Cary, NC 27513
Phone [phone]
General Information:
The total acreage of the project is 13.9 acres, located within the Cleveland Water
District. There are 3 vacant dwellings that exist on the property along NC 42. The
majority of the site was timbered approximately 7 years ago, so there is a
substantial amount of undergrowth present within the property. Wetland
vegetation exists on the western most corner of the project. The drainage is not
considered an intermittent stream but a wetland in this area. All necessary Corp
of Engineers and Division of Water Quality permits will be obtained for the placing
of fill for the project.
The project is not within the Environmentally Sensitive Overlay District.
Impervious Area:
Within the 100' of right-of-way, approximately 600' of pavement widening of NC 42
from 2 lanes to 3 lanes, and 400' of widening for NC 50 is required. The
pavement widening will not be curbed and gutter, but have grassed swales. The
site has been previously approved for a shopping center.
Based upon the stormwater manual, the allowable impervious area for Non-
Residential Outside of the ESOD is 60% with BMP's. Impervious area is 9.51
Acres of the 13.9 acres or 68.4%.
Land Dedication will be required unless the owner acquires an additional two
acres of land to get the impervious area to 60%. The required area for Land
Dedication is 8.4% x 13.9 acres = 1.16 x 1.5 factor = 1.75 acres. The owner is
proposing 1.0 acres of wetland acquisition in the NCEEP as part of the project for
wetland mitigation. The remaining 0.75 acres will be part of the Land Dedication
to Johnston County.

Land has not been identified at this time for the land dedication program. The
developers will work with the County to either identify land or will pay the land
dedication program per acre payment of $10,000.
Peak Runoff Reduction:
The pre condition has a Q(1) of 8.36 cfs, and the post condition is 1 cfs after being
routed through the constructed wetland. The Q(10) pre is 13.7 cfs, and the Q(10)
post is 6 cfs.
Nitrogen Loading -See Next Sheet
Existing Drainage ways
The project is located at the top of a ridge at the intersection of NC 42 and NC 50.
The drainage area drains into an intermittent stream that begins south of the
southwest property line. Eventually the basin drains into Buffalo Creek.
There is one culvert crossing at NC 42 draining into the project limits. The
drainage basin for the existing 18" culvert pipe is 18 acres.

Middle Creek Commons Commerical
Nitrogen Buydown
Area Export Coeff Export
Type of Land Cover (acres) (Ibs/ac/yr) (Ibs/yr)
Permanently protected undisturbed open space (forest, unmown meadow) 2 0.6 1.2
Permanently protected managed open space (grass, landscaping, etc.) 2.5 1.2 3
Impervious Area 9.5 21.2 201.4
TOTAL 14 23 205.6
N Load =Export /Area
Initial Target
Amount controlled by BMP
Final Target
Remaining N
Offset Fee Calculation
14.69
10
9.76 Bioretention/Wetland
3.6
1.33
N Payment = [($/Ib)(# of Ibs/year)(30 years) + (Land Cost $/Ac)(1 Ac / 35 Ac)(DeveL in Ac)] x (1.1 Adm Cost)
Offset Payment $27,343.17
$/Ib 11
#Ibs/yr 342
land cost $/ac (based on current tax value) 50000
1 ac/35 ac 0.029
area of development (ac) 9.5
administrative cost 1.1
$/lb =The cost of mitigation in dollars per pound of nitrogen mitigation.
# of lbs/year =The number of pounds of nitrogen exported or discharged each year
for which mitigation is being requested.
Land Cost $/Ac =The current property value, in dollars per acre, of the property
being developed, based upon the most recent county tax assessment.
1 Ac / 35 Ac = An adjustment factor, indicating that one acre of mitigation is
required for every 35 acres of development.
Devel in Ac =The overall size of the development, for which the mitigation is
requested, in acres.
Adm Costs =An adjustment factor, necessary to cover the administrative costs
associated with the requested mitigation.
commercial Page 1

PROJECT: Middle Creek Commons
Pre and Post Development Flows
Pre-Develo ment Flows Post-Develo ment Flows Flow Out
Drainage
Basin # Area
ac I (10)
(in/hr C-value Q(10)
cfs C-value Q(10)
(cfs of BMP
cfs
1 9.00 6.03 0.25 13.57 0.8 43.41 5.99
Pre-Develo ment Flows Post-Develo ment Flows Flow Out
Drainage
Basin # Area
(ac) I (1yr, 10min)
(in/hr) C-value Q(1)
cfs C-value Q(1)
cfs) of BMP
(cfs
1 9.00 3.71 0.25 8.36 0.8 26.74 1
Wetlandandnitrogen.xlsPreDevelopment Chas. H. Sells, Inc. 8/2/2006

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DWQ Project No.
DIVISION OF WATER QUALITY -LEVEL. SPREADER WORKSHEET
I. PROJECT INFORINATION (please complete the following information):
Project Name : (~~ t°~ ~,(LL; ~ ~C.. ~~~~~ t ~'.t
Contact Person: ca~.t .~ ~~~~ ~ ~G• Phone Number: ~' ~ ~ ~ ° OQ~
Level Spreader lD: .
Level Spreader Length ~- ~ ft. (perpendicular to flow)
Drainage Area ac. (on-site and off-site drainage to the level spreader)
Impervious Area ~ ac. (on-site and off-site drainage to the level spreader)
Maximum Filter Strip/Buffer Slope k % (6% for forested, leaf littler cover, 8% for thick ground cover
grass
Max. Discharge from 1"Mr Storm ~ ~ ~j cfs
Max. Discharge to Level Spreader ~ cfs
Filter Strip/Buffer Vegetation ca ~~=~~ (thick ground cover or grass, canopied forest with leaf fitter
groundcover)
Pre-treatment or Bypass Method Used ~S~S i c~ ~i ~c~ f,,~ E-~ F d~ ~"~
REQUIRED ITEMS CHECKLIST
Initial in the space provided to indicate the following design requirements have been met and supporting documentation is attached. if a
requirement has not been met, attach an explanation of urhy. At a minimum, a complete stormwater management plan submitta! includes
a worksheet for each BMP, design calculations, plans and specifications showing all BMPs and outlet structure details, 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 will substantially delay final review and approval of the project.
A lica~nts Initials
U tea Level spreader is at least 13 ft. per cfs for thick ground cover or grass or 65 ft per cfs in canopied forest with leaf
litter for 50-foot buffer; 50 ft per cfs for 100-foot buffer, or 40 ft. per cfs for 150-foot buffer.
Pre-Fom~ed Scour Holes are on flat stapes only.
~i No structures are located in protected buffers (must meet no practical alternatives criteria).
Design Altemative (if any) and Bypass method used:
~' Bypass conveyance method is specified and plan details and calculations are provided.
Alternative design option is specified and plan details and calculations are provided.
"~'.~ Discharge to level spreader and subsequent filter strip is hydraulically and spatially separate from the bypass
discharge.
~~ No structures are located in protected buffers.
t~+`~~ Plan details for the bypass and outlets are provided.
~~S The operation and maintenance agreement includes annual erosion and vegetation repair.
E }~ The operation and maintenance agreement signed and notarized by the responsible party is provided.

DWQ Project No.
DIVISION OF WATER QUAE.lTY - 4fl1 EXTENDED DETENTION (and POCKET*) WETLAND WORKSHEET
I. PROJECT INFORINATION (please complete the following information)'
Project Name : ~1 '~ ~~~ ~~- ~= 'rf'~ ~~'~`~
Contact Person: ~~1 ~l/G?t-- Phone Number: (, ~E~') ~ `~ " ~ d
For projects with multiple basins, specify which basin this worksheet applies to:
Permanent Pool Elevation ~- ~ ~ ft. (elevation of the orifice invert out)
Temporary Pool Elevation ~., ~.~ • S~ ft. (elevation of the outlet structure invert in)
Permanent Pool Surface Area ) `~~° ~ sq. ft. (water surface area at permanent pool elevation)
Drainage Area ~ • ~ ac. (on-site and off-site drainage to the basin)
Impervious Area .!~ ac. (on-site and off-site drainage to the basin)
Forebay Surface Area ~ ? ~ ~ sq. ft. (at permanent pool elevation approximately 15%)'
Marsh 0"-9" Surface Area ~r` `~ ~•- ~ sq. ft. (at permanent pool elevation approximately 35%)*
Marsh 9"-18" Surface Area ~ y ~- L sq. ft. (at permanent pool elevation approximately 35%)'
Micro Pool Surface Area 1 ~ ~ G sq. ft. (at permanent pool elevation approximately 15%)'
Temporary Pool Volume f ~',~ d ~ cu. ft. (volume detained on top of the permanent pool)

SA/DA used ~ . ' ~ (surface area to drainage area ratio)*
Diameter of Orifice t , c,} in. (draw down orifice diameter)
II. REQUIRED ITENiS CHECKLIST
Initial in the space provided to indicate the following design requirements have been met and supporting documentation is attached. If a
requirement has not been met attach an explanation of why. At a minimum, a complete stormwater management plan submittal includes
a worksheet for each BIJiP, design calculations, plans and specifications showing all BMPs and outlet structure details, a detailed
drainage p{an and a fully executed operation and maintenance agreement. An incomplete submittal package wiN result in a request for
additional information and will substantially delay final review and approval of the project
Aoolicants Initials
1 ~`t~The temporary pool controls runoff from the 1 inch rain.
The basin side slopes are no steeper than 3:1.
A planting plan for the marsh areas with plant species and densities is provided.
I : Vegetation above the permanent pool elevation is specified.
An emergency drain is provided to drain the basin.
~ The temporary pool draws down in 2 to 5 days.
~~ Sediment storage is provided in the permanent pool.
"D~'~ A sediment disposal area is provided.
f~~r.a Access is provided for maintenance.
~°" A site specific, signed and notarized operation ar~d rriaintenance agreement is provided.
~' ~ The drainage area (including any offsite area) is delineated on a site plan.
i l~ Access is provided for maintenance.
Plan details for the wetland are provided.
s~~~~ Plan details for the inlet and outlet are provided.
71,~~ A site specific operation and maintenance agreement, signed and notarized by the responsible party is provided (see
http://h2o.ehnr.state.nc.us/ncwetlands/oandm.doc).
* Pocket Wetlands have different design parameters and are only assumed to remove 35% TSS -See pp. 19 and 20 of the NC DENR
Stormwater BMP Manual, Apri11999.10% open water, 50% high marsh, 40% low marsh.

PROJECT: Middle Creek Commons
BMP#1 Wetland
02-Aug-06
DETERMINE SURFACE AREA AND VOLUME REQUIRED
DRAINAGE AREA (DA):
SUBDIVISION LOT SIZE:
IMPERVIOUS AREA:
68%
SA/DA (FROM TABLE 1.1 NC BMP MANUAL): 2.78
SURFACE AREA REQUIRED: 11,504 SF
RUNOFF VOLUME(Rv) _ .05+(.009*%IMP.*100): 0.66 IN/IN
VOLUME REQUIRED (V) = Rv*1""DA 22,820 CF
POND DEPTH CRITERIA:
HIGH MARSH (0-9" DEPTH) MIN .35% OF SA 4,026 SF
LOW MARSH (9-18" DEPTH) MIN. 35% OF SA 4,026 SF
OPEN WATER (> 18" DEPTH) MIN. 15% OF SA 1,726 SF
BALANCE OF AREA (15%): 1,726 SF
TOTAL SURFACE AREA: 11,504 SF
STAGE STORAGE TABLE
CONTOUR CONTOUR
AREA
SF INCR
VOLUME
CF ACCUM
VOLUME
CF Z
STAGE
FT % OF
NP
294 1,683 -2 15% >18"
295 5,801 -1 36% 9-18"
296 11,567 < -NORMAL POOL 0 50% 0-9"
297 13,176 12372 12,372 1 100%
298 14,852 14014 26,386 2
299 16, 595 15724 42,109 3
9.50 ACRES
na ACRE
0
1
2
1.75
VOLUME CHECK (PROPOSED/REQUIRED): 1.16

STORAGE POOL DRAWDOWN
BMP#1 Wetland
ORFICE EQUATION: Q=CpA(2gh)~~2
Number of Drains:
Diameter of Drains:
Area of Opening:
Orifice Coefficient:
Average Head: (Q10 el - NP el)/2
Average Flow (Orifice Equation=
Volume of Storage =
1
1.0 in
0.0055 ft
0.60 ft
7.40 ft
0.071 cfs
22,820 cf
Length of Drawdown = 319,593 sec or 88.78 hours OK

Hydrograph Return Period Recap
Hyd. Hydrograph Inflow Peak Outflow (cfs) Hydrograph
tion
descri
No. type
(origin) Hyd(s) 1-Yr 2-Yr 3-Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr p
1
2 Rational
Reservoir -------
1 26.69
1.76 33.10
4.53 -------
------- -------
------- 43.47
8.22 ------
------- -------
------- 60.13
13.71 Middle Creek-Wetland
WETLAND
Proj. file: Viletland.gpw Thursday, Atag 3 2006, 9:03 AM
hydrariow hyorograpns oy inteusoive

Hydrograph Summary Report
Hyd.
No. Hydrograph
type
(origin) Peak
flow
(cfs) Time
interval
(min) Time to
peak
(min) Volume

(cult) Inflow
hyd(s) Maximum
elevation
(ft) Maximum
storage
(cult) Hydrograph
description
1 Rational 26.69 1 10 16,015 ---- ------ ----- Middle Creek-Wetland
2 Reservoir 1.76 1 19 7,427 1 297.23 15,568 WETLAND
V1/etland:gpw Return Period: 1 Year Thursday, Rug 3 2006, 9:03 AM
Hydraflow Hydrographs by Intelisolve

3
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Thursday, Aug 3 2006, 9:3 AM
Hyd. r~o. ~
Middle Creek-Wetland
Hydrograph type =Rational Peak discharge = 26.69 cfs
Storm frequency = 1 yrs Time interval = 1 min
Drainage area = 9.000 ac Runoff coeff. = 0.8
Intensity = 3.707 in/hr Tc by User = 10.00 min
IDF Curve = SampleFHA.idf Asc/Rec limb fact = 1/1
Hydrograph Volume = 16,015 cult
Middle Creek-wetland
Q (cfs) Hyd. No. 1 -- 1 Yr
28.00
24.00
20.00
16.00
12.00
8.00
4.00
0 00
Q (cfs)
28.00
24.00
20.00
16.00
12.00
8.00
4.00
0 00
0.0 0.1 0.2 0.3 0.3
Time (hrs)
Hyd No. 1

Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Thursday, Aug 3 2006, 9:3 AM
Hya. r~o. 2
WETLAND
Hydrograph type =Reservoir Peak discharge = 1.76 cfs
Storm frequency = 1 yrs Time interval = 1 min
Inflow hyd. No. = 1 Max. Elevation = 297.23 ft
Reservoir name =Wetland Max. Storage = 15,568 cult
Storage Indication method used.
Q (cfs)
28.00
24.00
WETLAND
Hyd. No. 2 -- 1 Yr
Hydrograph Volume = 7,427 cult
20.00
16.00
12.00
8.00
4.00
0.00 -"
0
Q (cfs)
28.00
24.00
20.00
16.00
_. __ _ _.
12.00
8.00
4.00
0.00
5 10 15 19 24 29 34 39 44 48
Time (hrs)
Hyd No. 2 Hyd No. 1
4

Hydrograph Summary Report
Hyd.
No. Hydrograph
type
(origin) Peak
flow
(cfs) Time
interval
(min) Time to
peak
(min) Volume

(tuft) Inflow
hyd(s) Maximum
elevation
(ft) Maximum
storage
(cult) Hydrograph
description
1 Rational 33.10 1 10 19,861 ---- ---- ------ Middle Creek-Wetland
2 Reservoir 5.55 1 18 13,111 1 298.55 19,065 WETLAND
Wetland.gpw Return Period: 2 Year Wednesday, Aug 2 2006, 7:06 PM
Hydraflow Hydrographs by Intelisolve

6
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Wednesday, Aug 2 2006, 7:6 PM
Hyd. tNo. 1
Middle Creek-Wetland
Hydrograph type =Rational Peak discharge = 33.10 cfs
Storm frequency = 2 yrs Time interval = 1 min
Drainage area = 9.000 ac Runoff coeff. = 0.8
Intensity = 4.597 in/hr Tc by User = 10.00 min
IDF Curve = SampleFHA.idf Asc/Rec limb fact = 1/1
Hydrograph Volume = 19,861 cult
Q (cfs)
35.00
30.00
25.00
20.00
15.00
10.00
5.00
0.00 ~-
0.0
Middle Creek-1l'detlar~d
Hyd. No. 1 -- 2 Yr
0.1
Hyd No. 1
0.2
0.3
Q (cfs)
35.00
30.00
25.00
20.00
15.00
10.00
5.00
~- 0.00
0.3
Time (hrs)

7
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Wednesday, Aug 2 2006, 7:6 PM
Hyd. No. 2
WETLAND
Hydrograph type =Reservoir Peak discharge = 5.55 cfs
Storm frequency = 2 yrs Time interval = 1 min
Inflow hyd. No. = 1 Max. Elevation = 298.55 ft
Reservoir name =Wetland Max. Storage = 19,065 cult
Storage Indication method used.
WETLAND
Hydrograph Volume = 13,111 cult

Hydrograph Summary Report
Hyd.
No. Hydrograph
type
(origin) Peak
flow
(cfs) Time
interval
(min) Time to
peak
(min) Volume

(tuft) Inflow
hyd(s) Maximum
elevation
(ft) Maximum
storage
(tuft) Hydrograph
description
1 Rational 43.47 1 10 26,084 ---- ----- ------ Middle Creek-Wetland
2 Reservoir 5.99 1 19 19,703 1 298.98 24,690 WETLAND
Wetland.gpw Return Period: 10 Year Wednesday, Auk 2 2006, 7:06 PM
Hydraflow Hydrographs by Intelisolve

9
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Wednesday, Aug 2 2006, 7:6 PM
Hyd. No. 1
Middle Creek-Wetland
Hydrograph type =Rational Peak discharge = 43.47 cfs
Storm frequency = 10 yrs Time interval = 1 min
Drainage area = 9.000 ac Runoff coeff. = 0.8
Intensity = 6.038 in/hr Tc by User = 10.00 min
IDF Curve = SampleFHA.idf Asc/Rec limb fact = 1/1
Hydrograph Volume = 26,084 cult
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0 00
Middle creek-~etlar~d
Hyd. No. 1 -- 10 Yr
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0 00
0.0 0.1 0.2 0.3 0.3
Time (hrs)
Hyd No. 1

Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Wednesday, Aug 2 2006, 7:6 PM
Hyd. No. 2
WETLAND
Hydrograph type =Reservoir Peak discharge = 5.99 cfs
Storm frequency = 10 yrs Time interval = 1 min
Inflow hyd. No. = 1 Max. Elevation = 298.98 ft
Reservoir name =Wetland Max. Storage = 24,690 cult
Storage Indication method used. Hydrograph Volume = 19,703 cult
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0 00
1NETLA{~D
Hyd. No. 2 -- 10 Yr
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0.00
10
0.0 0.3 0.7 1.0 1.3 1.7 2.0 2.3 2.7 3.0 3.3
Time (hrs)
Hyd No. 2 Hyd No. 1

11
Hydrograph Summary Report
Hyd.
No. Hydrograph
type
(origin) Peak
flow
(cfs) Time
interval
(min) Time to
peak
(min) Volume

(tuft) Inflow
hyd(s) Maximum
elevation
(ft) Maximum
storage
(cult) Hydrograph
description
1 Rational 60.13 1 10 36,079
____
______
______
Middle Creek-Wetland
2 Reservoir 6.63 1 19 30,290 1 299.64 34,409 WETLAND
VVetland.gp~ Return Period: 100 Year Wednesday, Aug 2 2006, 7:06 PM
Hydraflow Hydrographs by Intelisolve

12
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Wednesday, Aug 2 2006, 7:6 PM
Hyd. No. 1
Middle Creek-Wetland
Hydrograph type =Rational Peak discharge = 60.13 cfs
Storm frequency = 100 yrs Time interval = 1 min
Drainage area = 9.000 ac Runoff coeff. = 0.8
Intensity = 8.352 in/hr Tc by User = 10.00 min
IDF Curve = SampleFHA.idf Asc/Rec limb fact = 1/1
Hydrograph Volume = 36,079 tuft
Middle Creek-Wetland
Q (cfs) Hyd. No. 1 -- 100 Yr
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00 -
0.0
0.1
Hyd No. 1
0.2
0.3
Q (cfs)
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00
0.3
Time (hrs)

Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Wednesday, Aug 2 2006, 7:6 PM
Hyd. No. 2
WETLAND
Hydrograph type =Reservoir Peak discharge = 6.63 cfs
Storm frequency = 100 yrs Time interval = 1 min
Inflow hyd. No. = 1 Max. Elevation = 299.64 ft
Reservoir name =Wetland Max. Storage = 34,409 cult
Storage Indication method used.
Q (cfs)
70.00
60.00
50.00
40.00
30.00 -
20.00 -
10.00 -
Q (cfs)
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00 ` ' ' ' ' ~ 0.00
0.0 0.3 0.7 1.0 1.3 1.7 2.0 2.3 2.7 3.0 3.3 3.7
Time (hrs)
Hyd No. 2 Hyd No. 1
'~iii`ETLQ-N D
Hyd. No. 2 -- 100 Yr
Hydrograph Volume = 30,290 cult
13

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OPERATIONS AND MAINTENANCE MANUAL
Project:
Middle Creek Commons
WATERSHED PROTECTION CONSTRUCTED WETLAND
JOHNSTON COUNTY, NC
Owners: Regency Centers LLP
101 Maynard Crossings Center
Cary, NC 27513
Prepared By: Donald A. Sever, P.E., Chas H Sells, Inc.
Date: September 1, 2006
Project: BMP Constructed Wetland
Date Constructed: Grading scheduled for Early 2007
Location: At the southwest corner of NC 42 and NC 50 intersection in Johnston County,
North Carolina
Receiving Water Course: Branch to Buffalo Creek

OPERATIONS AND MAINTENANCE MANUAL
MIDDLE CREEK COMMONS STORMWATER CONSTRUCTED WETLAND AREA
This manual establishes procedures for maintenance and operation of the Middle Creek
Commons Constructed Wetland area (s) in accordance with the JOHNSTON COUNTY
guidelines.
MAINTENANCE OF CONSTRUCTED WETLAND AREAS
Vegetation-The drainage areas have a ground cover of wetland plantings outside of
the ponding area, which if properly maintained wi!I prevent erosion of the embankment
and provide an easy surface for inspection. The grass will be most difficult to obtain in
the area subject to water level fluctuation, and has been planted above the inundated
areas. Grass should be fertilized every October and April. Wetland plants are located
within all water level fluctuation areas. Check vegetation conditions within the
constructed wetland area and replace if necessary any damaged plant materials
Re-Seeding-Periodic re-seeding may be required to establish grass on areas where
seed did not take or have been destroyed. Before seeding, fertilizer (12-12-12) should
be applied at a minimum rate of 12 to 15 pounds per 1,000 SF. The seed should be
evenly sown at a rate of three pounds per 1,000 SF. The seed should be covered with
soil to the depth of approximately '/4". Immediately following the planting, the area
should be mulched with straw.
Trees and Shrubs-Trees, shrubs and other landscape vegetation should be permitted
only as shown on the approved planting plan. The vegetation should be kept healthy
and vibrant. If a tree or shrub dies it should be removed and replaced with another tree
or shrub from the same species (see attached maintenance schedule).
Mowing-Grass mowing, brush cutting and removal of weed vegetation will be
necessary for the proper maintenance of the areas. All area slopes and vegetation
should be mowed when the grass exceeds 8" in height. Acceptable methods include
the use of weed whips or power brush cutters and mowers.
Erosion-Erosion occurs when the water concentrates causing failure of the vegetation
or when vegetation dies and sets up the environment for rill erosion and eventually
gullies from the stormwater runoff. The areas should be inspected. Proper care of
vegetative areas that develop erosion is required to prevent more serious damage to
the site. Rills and gullies should be filled with suitable soil compacted and then seeded.
Methods described earlier on vegetation should be used to properly establish the grass
surface. Where eroded areas are detected, the cause of the erosion should be
addressed to prevent a continued maintenance problem. Frequently, problems result

from the concentration of runoff to one point of the constructed wetland area instead of
a uniform distribution of runoff. This can be corrected by reshaping, to more evenly
distribute the runoff to areas not experiencing erosion problems.
Rodent Control-Generally in this urban environment, rodents are not a problem.
Rodents such as groundhogs, muskrats and motes are attracted to moist, wet areas
and can be quite dangerous to structural integrity and proper performance of the
earthwork and drainage. Groundhogs and muskrats thrive on burrowing into the
manmade earthwork, which become pathways for seepage. In the event that burrows
are detected within the constructed wetland area, the rodents should be dealt with by
removal.
Trash and Debris--Trash acts as a barrier to stormwater infiltration and attracts
unwanted pests. The constructed wetland area should be kept clear of debris such as
loose bottles, cans, food containers and other forms of rubbish. The area should be
cleared of debris as needed, but no less than twice a year.
MAINTENANCE OF SPILLWAYS AND CONTROL STRUCTURE
Inspection of Conduits--Conduits should be inspected thoroughly once a year. Conduits
should be visually inspected at the joints. Pipes should be inspected for proper
alignment (sagging), elongation and displacement at joints, cracks, leaks, surface wear,
loss of protective coating, corrosion and blocking. Problems with conduits most often
occur at joints and special attention should be given to them during inspection. Joints
should be checked for gaps caused by elongation or settlement and loss of joint filler
material. Open joints can permit erosion of the earthwork and possibly the piping of soil
material through the joints. A depression in the soil surface over the pipe may be signs
that soil is being removed from around the pipe.
OPERATION
Drainpipes--Drainpipes should always be operable so that the water can be drawn down
in the. event of severe rain or for repairs or maintenance.
Record Keeping--Operation of constructed wetland area should include recording of the
following:
Annual Inspection Reports--A collection of written inspection reports should be
kept on record in Section IV of this manual. Inspection should be conducted
annually. Copies should be provided to the Town of JOHNSTON COUNTY
stormwater Management Section of the Engineering Department.
Observations--All observations should be recorded. Where periodic inspections
are performed following significant rainfall, these inspections should be logged
into the Periodic Inspection, Operations and Maintenance Form in Section IV of
this manual.
Maintenance--Written records of maintenance and/or repairs should be recorded
on the Periodic Inspection, Operation and Maintenance Form in Section IV of this
manual.

Other Operational Procedures--The owner should maintain a complete and up-to-date
set of plans (as-built drawings) and all changes made to the constructed wetland area
over time should be recorded on the as-builts.
Sedimentation and Dredging--Sedimentation from on-site and off-site soils will
eventually result in the clogging of drainage conduits and will have to be removed. The
frequency of this sediment removal can be reduced by ensuring that the site areas
around the building be stabilized with a vegetative ground cover such that it restrains
erosion. This would include a periodic application of fertilizer and/or other treatment
necessary to promote a stable ground cover and minimize sedimentation to the pond.
The removed material should be hauled offsite to a suitable landfill site or mounded
somewhere on site and stabilized with a ground cover sufficient to restrain erosion.
Example Maintenance Schedule for constructed wetland Areas
Descri tion Method Fre uenc Time of ear
SOIL
Ins ect and re air erosion Visual Monthl All ear
ORGANIC LAYER
Remulch an void area B hand As needed As needed
Remove previous mulch By hand Once every Spring
layer before applying new 2-3 years
la er optional
An additional mulch added B hand Once a ear Sprin
PLANTS
Removal and replacement See planting Twice a year As directed by
of all dead and diseased specifications landscaper
vegetation considered
be and treatment
Treat all diseased trees Mechanical N/A Varies, dependent
and shrubs or by hand on insect or disease
infestation
Removal of cattails and By hand or As needed As needed
other invasive species through hand
application of
herbicide
Watering of plant material By hand Daily Immediately after
shall take place at the end completion of project
of each day for fourteen
consecutive days and after
lantin is completed
Replacement of support By hand Once a year Only remove stake
stakes in the sprin
Replace any deficient By hand As needed As needed
stakes or wires
IV. INSPECTION, OPERATION AND MAINTENANCE CHECKLISTS

POND INSPECTION CHECKLIST
Date
Time
Middle Creek Commons Constructed Wetland Pond
JOHNSTON COUNTY, NC
INSPECTORS
SPILLWAYS • DRAINS • OUTLETS ACTION

HECK/CIRCLE
CONDITION NOTED

BSERVATIONS R
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P
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S M
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V
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Princi al Spillwa T e:
trashrack/debris
cracks/deterioration

improper ali nment
cracks/deterioration
joint deterioration

seeps a/pipin
Undercuttin
Erosion
Debris

Lake Drain/Other Outlets T pe:
Gate/valves
Operabilit

GENERAL COMMENTS, SKETCHES & FIELD MEASUREMENTS

PERIODIC INSPECTION, OPERATION Middle Creek Commons Constructed Wetland
AND MAINTENANCE RECORDS Pond
JOHNSTON COUNTY, NC
DATE TIME RAIN POOL WEATHER
LEVEL CONDITIONS
RECORDED
GENERAL OBSERVATIONS OR COMMENTS BY
DATE I MAINTENANCE PERFORMED
DATE EQUIPEMENT OPERATED
COMMENTS RECORDED
BY
COMMENTS BYCORDED
POND INSPECTION CHECKLIST
Date
Time

Middle Creek Commons Constructed Wetland Pond
JOHNSTON COUNTY, NC
INSPECTORS
EMBANKMENT • POOL ACTION

HECK/CIRCLE
CONDITION NOTED

BSERVATIONS R
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P
A
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s M
0
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o
R I
V
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S
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a
T
I
V
E
U/S SLOPE
ve etation/n ra
beachin /slides/cracks
underminin /erosion
rodent burrows

CREST
ruts/erosion
cracks/settlement
oor ali nment

D/S SLOPE
ve etation/erosion
rodent burrows
slou h/slides/cracks
see a e/wetness

POOL
erosion/ round cover
sedimentation
water ualit

ABUTMENT
ve etation/erosion
slou h/slides/cracks
see a e/wetness

GENERAL COMMENTS, SKETCHES & FIELD MEASUREMENTS

OPERATIONS AND MAINTENANCE MANUAL
STORMWATER CONTROL STRUCTURE LEVEL SPREADER
JOHNSTON COUNTY, NC
Project: Middle Creek Commons
Owners: Regency Centers LLP
101 Maynard Crossings Center
Cary, NC 27513
Prepared By: Donald A. Sever, P.E., Chas H Sells, Inc.
Date: September 1, 2006
Project: BMP Constructed Wetland
Date Constructed: Grading scheduled for Early 2007
Location: At the southwest corner of NC 42 and NC 50 intersection in Johnston County,
North Carolina
Receiving Water Course: Branch to Buffalo Creek

OPERATIONS & MAINTENANCE MANUAL
(Project Name): LEVEL SPREADER
This manual established procedures for maintenance and operation of the LEVEL
SPREADER in accordance with the Johnston County Stormwater guidelines.
Maintenance of level spreader
A. Vegetation -Sod shall be used for the instillation of the level spreader
(fescue). The level spreader shall be properly maintained to ensure an
adequate ground cove of fescue, which if properly maintained will prevent
erosion. Fertilizer rates should be kept to a minimum.
• Re-Seeding -periodically re-seeding may be required to establish grass
on areas where seek did not take or has been destroyed. Before seeding,
fertilizer (12-12-12) should be applied at a minimum rate of 12 to 15
pounds per 1,000 SF. The seed should be evenly sewn at a rate of three
pounds per 1,000 SF. The seed should be covered with soil to the depth
of approximately '/4". Immediately following the planting, the area should
be mulched with straw.
• Trees & Shrubs -trees, shrubs, and other landscape vegetation shall not
be permitted with the level spreader. Periodic inspections and
maintenance shall be performed to remove intrusive vegetation.
• Mowing -grass mowing, removal of weed vegetation will be necessary for
the proper maintenance of the level spreader. A level spreader should be
mowed when the grass exceeds 4" in height (maximum 8"). Acceptable
methods include the use of weed whips or power brush cutters and
mowers.
B. Erosion -Erosion occurs when the water concentrates causing failure of the
vegetation or when vegetation dies and sets up the environment for rill
erosion and eventually gullies from the stormwater runoff. The level spreader
should be inspected erosion form occurring. Proper care of vegetative areas
that develop erosion is required to prevent more serious damage to the
Stormwater Best Management Practice (BMP). Rills and gullies should be
filled with suitable soil compacted and then seeded. Methods described
earlier on vegetation should be .used to properly establish the grass surface.
Where eroded areas are detected, the cause of the erosion should be
addressed to prevent a continued maintenance problem. Frequently
problems result from the concentration of runoff to one point of the level
spreader instead of a uniform distribution of runoff. This can be corrected by
reshaping the level spreader to more evenly distribute the runoff to areas,
which are not experiencing erosion problems.

C. Rodent Control
Generally in this urban environment, rodents are not a problem. Rodents
such as ground hogs, muskrats, and beavers are attracted to dams and
reservoirs and can be quite dangerous to structural integrity and proper
performance of the embankment and spillway. Groundhog and muskrats
thrive on burrowing in the manmade earth earthwork, which become
pathways for seepage. In the event that burrows are detected within the level
spreader, then the rodents should be dealt with by removal.
Trash and Debris -Trash acts as a barrier to stormwater flow and attracts
unwanted pests. The level spreader and downstream storm inlet should be
kept clear of debris such as loose bottles, cans, food containers and other
forms of rubbish. The area should be kept clear of debris as directed in the
maintenance agreement.
II. OPERATION
Level spreader -the level spreader should always be operational so that the
water is distributed evenly across the width of the level spreader and flows
the entire length of the level spreader. Any obstruction that prevents even
destitution of the stormwater flow within the level spreader shall be removed
and any signs of erosion shall be repaired immediately after observed.
A. Record Keeping
Operation of a level spreader should include recording of the following:
• Annual Inspection Reports - a collection of written inspection reports
should be kept on record in Section IV of this manual. Inspection should
be conducted annually. Copies should be provided to the Johnston
County Environmental Protection Administrator.
• Observations -all observations should be recorded. Where periodic
inspections are performed following significant rainfall events, these
inspections should be logged into the Periodic Inspection, Operation &
Maintenance Form.
• Maintenance -written records of maintenance and/or repairs should be
recorded on the Periodic Inspection, Operation & Maintenance Form.
• Other Operation Procedures -the owner should maintain a complete and
up-to-date set of plans (as-built drawings) and all changes made to the
level spreader over time should be recorded on the as-builts.

LEVEL SPREADER INSPECTION CHECKLIST
Date:
Time:
Middle Creek Commons Level Spreader
Date Observations Action - Action - Action --
Re air Monitor Investi ative
General Comments, Sketches & Field Measurements

RESERVOIR WATERSHED PROTECTION IMPOUNDMENT MAINTENANCE AGREEMENT
PROJECT: Middle Creek Commons Shopping Center
BMP Constructed Wetland and Level Spreader per plans completed by Chas H. Sells. Inc
RESPONSIBLE PARTY: Regency Centers, LLC PHONE #: [phone]
ADDRESS: 101 Maynard Crossing Center, Cary, NC 27513
Monthly or after every runoff producing rainfall, whichever comes first:
a. Remove debris from trash rack.
b. Check and clear orifice of any obstructions.
c. Check pond side slopes; remove trash, repair eroded areas before next rainfall.
Quarterly
a. Inspect the collection system (i.e., catch basin, piping, grassed swales) for proper functioning.
Clear accumulated trash from basin grates, and basin bottoms, and check piping for obstructions.
b. Check pond inlet pipes for undercutting. Repair if necessary.
c. Repair any broken pipes.
d. Replace rip rap that is choked with sediment.
III. Semi-Annually
a. Remove accumulated sediment from bottom of outlet structure.
b. Check pond depth at various locations. If depth is reduced to 75% of original design depth, remove
sediment to original design depth.
c. Reseed grassed swales twice yearly. Repair eroded areas immediately.
IV. Annual
a. Submit report to the Environmental Protection Administrator with the following information:
• Site map with specific BMP identified by number or letter
• Owner name
• Inspector name, Professional Engineer registration seal, signature and date
• Weather at time of inspection
• Most recent rain event date and approximate amount
• BMP type
• Specific information about the condition of the BMP
• Note any repairs needed or made
• Provide at least two pictures of the structure, showing the inflow and outflow area.
IV. General
a. Mow side slopes according to the season. Maximum grass height to be six (6) inches.
b. Cattails are encouraged along pond perimeter, however, they must be removed when they cover
the entire surface area of pond.
c. All components of impoundment system to be kept in good working order.
d. In case the ownership of the Impoundment Transfers, the current owner shall, within thirty (30) days
of transfer of ownership, notify the Johnston County Environmental Protection Administrator, of
such ownership transfer.
e. This property and impoundment is also subject to the Operation and Maintenance Manual filed with
the register of deeds.

I, ,hereby acknowledge that I am the financially responsible party for
maintenance and inspection of this impoundment. I will perform the maintenance as outlined above, to comply
with the Johnston County Stormwater Management Ordinance and the Stormwater Management permit
received for this project. Furthermore, I attest that this Inspection and Maintenance Agreement is on file with
the Register of Deeds.
Signature:
I,
do hereby certify that
200_
hand and official seal,
Seal
Date:
_, a Notary Public for the State of ,County of ,
personally appeared before me this day of
and acknowledge due execution of the foregoing instrument. Witness my
My commission expires:
ckc
Maintenance Agreement