20070081 Ver 2_More Info Received_20070807

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Letter of Transmi tal
To:

Aiken & Yelle Associates, PA
AYES Professional Engineers & Land Surveyors
3755 Benson Drive
Raleigh, North Carolina 27609
919-877-9992 Fax [phone]
e-mail: [e-mail]
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STORMWATER
OPERATION & MAINTENANCE MANUAL
AND BUDGET
FOR BIO RETENTION AREAS
IN
CEDAR RIDGE SUBDIVISION
PHASES 2, 3, 4 & 5
Prepared by:
Aiken & Yelle Associates, PA
3755 Benson Drive
Raleigh, NC 27609
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OPERATIONS AND MAINTENACE MANUAL
SECTION I- INTRODUCTION:
This manual establishes procedures for maintenance and operation of stormwater in
accordance with the guidelines as set forth in the NCDWQ Stormwater Management
Design Manual. The NCDWQ rules require that stormwater devices be inspected
annually and that they be maintained in accordance with this document. Any repairs that
become necessary as a result of periodic inspections shall be completed within thirty (30)
calendar days of filing the report unless written approval of and extension is obtained
from the Town of Rolesville or NCDWQ.
The storm water management plan for this site consists of only water quality Bio
Retention areas. The Bio Retention areas are to serve as a bio-filtration to reduce the
nitrogen loading from the proposed impervious surface.
This development will be developed in four phases as approved by the Town of
Rolesville as depicted on the preliminary site plan on file in the Town of Rolesville
Planning Department. All phasesl will be developed in accordance with construction
drawings entitled "Cedar Ridge Subdivision", prepared by Aiken & Yelle Associates,
PA, dated August 7, 2007 and approved by Town of Rolesville Central Engineering
Division. Therefore the water quality Bio Retention areas will also be installed by
phases. The Bio Retention areas to be constructed by phases are as follows:
A. Phase 2
Phase 2 of this development plan includes the construction of one (1) water quality
Bio Retention area as shown on the "Cedar Ridge Subdivision- Phase 2, 3, 4 and 5
Construction Drawings", prepared by this firm, dated 08/07/07.
Bio Retention area #1 will be constructed within a public drainage easement on Lot
111 of the proposed subdivision. More specifically the Bio Retention area will be
located down stream from storm sewer manhole #73. The Bio Retention surface area
required is be 1700 SF (approx. 95 feet in length and 18 feet in width) with side
slopes of 3 (H): 1'(V) and a depth of 1 foot.
B. Phase 3
Phase 3 of this development plan includes the construction of one (1) water quality
Bio Retention area as shown on the "Cedar Ridge Subdivision- Phase 2, 3, 4 and 5
Construction Drawings", prepared by this firm, dated 08/07/07.
Bio Retention area #11 will be constructed on Lots 65 & 66 of the proposed
subdivision. More specifically the Bio Retention area will be located down stream
from storm sewer manhole #2 (SMH#2). The Bio Retention surface area required is
Page 2 o f 1-~

2,000 SF (approx. 65 feet in length and 36 feet in width) with side slopes of 3 (H):
1'(V) and a depth of 1 foot.
C. Phase 4
Bio Retention area #2 will be constructed within a designated open space area
proposed for this subdivision. More specifically the Bio Retention area will be
located down stream from storm sewer manhole #61 B (SMH#61 B). The Bio
Retention surface area will be 3,000 SF (approx. 85 feet in length and 50 feet in
width) with side slopes of 3 (H): 1'(V) and a depth of 1 foot.
Bio Retention area #3 will be constructed within a designated open space area
proposed for this subdivision. More specifically the Bio Retention area will be
located down stream from storm sewer manhole #64 (SMH#64). The Bio Retention
surface area will be 950 SF (approx. 66 feet in length and 50 feet in width) with side
slopes of 3 (H): 1'(V) and a depth of 1 foot.
Bio Retention area #4 will be constructed within a public drainage easement on Lot
100 of the subdivision. More specifically the Bio Retention area will be located down
stream from storm sewer manhole #57 (SMH#57). The Bio Retention surface area
will be 2,300 SF (approx. 141 feet in length and 23 feet in width) with side slopes of
3 (H): 1'(V) and a depth of 9 inches.
Bio Retention area #5 will be constructed within a public drainage easement on Lot
94 of the subdivision. More specifically the Bio Retention area will be located down
stream from storm sewer manhole #51 (SMH#51). The Bio Retention surface area
will be 2,000 SF (approx. 100 feet in length and 27 feet in width) with side slopes of
3 (H): 1'(V) and a depth of 1 foot.
Bio Retention area #6 will be constructed within a public drainage easement on Lot
87 of the subdivision. More specifically the Bio Retention area will be located down
stream from storm sewer manhole #40 (SMH#40). The Bio Retention surface area
will be 850 SF (approx. 54 feet in length and 18 feet in width) with side slopes of 3
(H): 1'(V) and a depth of 1 foot.
Bio Retention area #7 will be constructed within a public drainage easement on Lot
80 of the subdivision. More specifically the Bio Retention area will be located down
stream from storm sewer manhole #33 (SMH#33). The Bio Retention surface area
will be 1,850 SF (approx. 64 feet in length and 39 feet in width) with side slopes of 3
(H): 1'(V) and a depth of 1 foot.
Bio Retention area #8 will be constructed within a public drainage easement on Lot
70 of the subdivision. More specifically the Bio Retention area will be located down
stream from storm sewer manhole #24 (SMH#24). The Bio Retention surface area
will be 2,700 SF (approx. 119 feet in length and 27 feet in width) with side slopes of
3 (H): 1'(V) and a depth of 1 foot.
Page 3 o f 1=~

Bio Retention area #9 will be constructed within a designated open space area
proposed for this subdivision. More specifically the Bio Retention area will be
located down stream from storm sewer manhole #13 (SMH#13). The Bio Retention
surface area will be 2,050 SF (approx. 88 feet in length and 32 feet in width) with
side slopes of 3 (H): 1'(V) and a depth of 1 foot.
Bio Retention area #10 will be constructed within a designated open space area
proposed for this subdivision. More specifically the Bio Retention area will be
located down stream from storm sewer manhole #10 (SMH#10). The Bio Retention
surface area will be 500 SF (approx. 36 feet in length and 17 feet in width) with side
slopes of 3 (H): 1'(V) and a depth of 1 foot.
D. Phase 5
Phase 5 of this development plan includes the construction of one (1) water quality
Bio Retention area as shown on the "Cedar Ridge Subdivision- Phase 2, 3, 4 and 5
Construction Drawings", prepared by this firm, dated 08/07/07.
Bio Retention area #11 will be constructed on Lots 156 & 164 of the proposed
subdivision. More specifically the Bio Retention area will be located down stream
from headwall #38 (HW#38). The Bio Retention surface area required is 1,250 SF
(approx. 209 feet in length and 6 feet in width) with side slopes of 3 (H): 1'(V) and a
depth of 1 foot.
SECTION II- WATER QUALITY BIO RETENTION AREA MAINTENANCE
REQUIREMENTS:
1. Watering: Plants should be selected to be tolerant of the bioretention facility's
particular conditions. Watering should not be required after establishment
(about 2 to 3 years). However, watering may be required during prolonged dry
periods after plants are established.
2. Erosion Control: Inspect flow entrances, ponding area, and surface overflow areas
periodically. Replace soil, plant material, and/or mulch in areas where erosion
has occurred. Erosion problems should not occur with proper design except
during extreme weather events. If erosion problems do occur, the following
issues should be re-assessed: flow volumes from the contributing drainage area
and bioretention size; flow velocities and gradients within the bioretention
facility; flow dissipation and erosion protection methods in the pretreatment and
in-flow areas. If sediment is deposited in the bioretention facility, immediately
determine the source, remove excess deposits, and correct the problem.
3. Plant Material: Depending on plants selected and aesthetic requirements,
occasional pruning and removal of dead plant material may be necessary.
Replace all dead plants. However, if specific plants consistently have a high
mortality rate, assess the cause and replace with appropriate species. Periodic
Page =l of 1=l

weeding is necessary until groundcover plants are established. Weeding should
become less frequent if an appropriate plant density has been used.
4. Nutrients and Pesticides: The soil media and plant material should have been
selected for optimum fertility, plant establishment, and growth within the
particular conditions of each bioretention facility. Nutrient and pesticide inputs
should NOT be required and will degrade the pollutant processing capability of
the bioretention facility, as well as contribute to additional pollutant loading to
receiving waters. By design, bioretention facilities are typically specified in
watersheds where phosphorous and nitrogen levels are often elevated.
Therefore, these should not be limiting nutrients with regard to plant health. If
in question, have the soil analyzed for fertility.
5. Mulch: Replace mulch annually in bioretention facilities where heavy metal
deposition is likely (e.g., drainage areas that include commercial/industrial uses,
parking lots, or roads). In residential or other settings where metal deposition is
not a concern, replace or add mulch as needed to maintain a 2 to 4 inch depth at
least once every two years.
6. Soil media: Soil mixes for bioretention facilities are design to maintain long-term
fertility and pollutant processing capability. Estimates from metal attenuation
research indicates that metal accumulation should not present a toxicity concern
for at least 20 years in bioretention facilities (USEPA 2000). Further, replacing
mulch where heavy metal deposition is likely provides an additional factor of
safety for prolonged bioretention performance. If in question, have soil analyzed
for fertility and pollutant levels.
When the filtering capacity diminishes substantially (e.g., when water ponds on the
surface for more than 12 hours), remedial actions must be taken. One possible problem
is that underdrain pipe systems can become clogged. Annual flushing through pipe
cleanouts is recommended to facilitate unclogging of the pipes without disturbing the
bioretention areas. If the water still ponds for more than 12 hours, the top few inches of
material should be removed and replaced with fresh material. The removed sediments
should be disposed of in an acceptable manner (e.g., landfill). If that does not solve the
problem, more extensive rebuilding is required.
Examples of When to Perform Maintenance
Thin Mulch in the Bioretention Cell
Remove top layer of fill media when the pool does not drain quickly. The pool is
designed to drain within 12 hours.
Operation 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.
Page J o f 1 ~

-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. 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.
Inspection and Maintenance Provisions for Bioretention Areas
BMP element Potential problems How to remediate the
problem
The entire BMP Trash/debris is present Remove the trash/debris
The perimeter of the Areas of bare soil and/or Regrade the soil if
bioretention cell erosive gullies have necessary to remove the
formed. 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
stone verge or swale applicable). of the sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged (if
applicable). Regrade the swale if
necessary to smooth it
Erosion is occurring in over and provide erosion
the control devices such as
swale (if applicable). reinforced turf matting or
riprap to avoid future
problems with erosion.
Stone verge is clogged or Remove sediment and
covered in sediment (if clogged stone and
applicable) replace with clean stone.
Page 6 of 14

Inspection and Maintenance Provisions for Bioretention Areas continued
BMP element::: Potential problems How to remediate the
problem
The pretreatment area Flow is bypassing Regrade if necessary to
pretreatment area route all flow to the
and/or gullies have pretreatment area.
formed. Restabilize the area
after radin
Sediment has Search for the source of
accumulated to a depth the sediment and
greater than three remedy the problem if
inches. possible. Remove the
sediment and restabilize
the retreatment area.
Erosion has occurred. Provide additional
erosion protection such
as reinforced turf
matting or riprap if
needed to prevent future
erosion roblems.
Weeds are present Remove the weeds,
preferably by hand.
The bioretention cell: Best professional Prune according to best
Vegetation practices professional
show that pruning is practices.
needed
to maintain optimal plant
health.
Plants are dead, Determine the source of
diseased or the problem: soils,
dying. 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 Remove tree stake/wires
present (which can kill the tree if
six months after not removed).
plantin .
Page 7 o f 14

The bioretention cell: Mulch is breaking down Spot mulch if there are
soils and mulch or only random void areas.
has floated away. Replace whole mulch
layer if necessary.
Remove the remaining
much and replace with
triple shredded hard
wood mulch at a
maximum depth of three
inches.
The bioretention cell: Soils and/or mulch are .Determine the extent of
soils and mulch clogged with sediment. the clogging-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
possible
An annual soil test Dolomitic lime shall be
shows that applied as
pH has dropped or recommended per the
heavy soil test and toxic soils
metals have shall be removed,
accumulated in disposed of properly and
the soil media. replaced
with new plantin media.
The underdrain system Clogging has occurred Wash out the underdrain
(if applicable system
The drop inlet Clogging has occurred Clean out the drop inlet.
Dispose of the sediment
off-site.
The drop inlet is Repair or replace the
damaged drop inlet.
The receiving water Erosion or other signs of Contact the NC Division
damage have occurred of Water Quality 401
at the outlet. Oversight Unit at 919-
~ 733-1786.
Page 8 of 14

SECTION V: OPERATION
A. Record Keeping
Operation of the storm water maintenance device should include recording of the
following:
• Annual Inspection Reports- Inspections should be conducted. A
professional engineer or his/her representative should conduct the
inspection. Reports should be kept on file with the Homeowner's
Association and a copy given to the Central Engineering Division of the
Town of Rolesville.
• Observations- All visual observations should be recorded. Where periodic
visual inspections are performed following significant rainfall events (2"
of rainfall in 24 hours or greater event), these inspections should be logged
into the Periodic Inspections, Operation & Maintenance Form in Section
X of this manual.
• Maintenance- Written reports of maintenance and/or repairs should be
recorded on the Periodic Inspections, Operation & Maintenance Form in
Section X of this manual.
B. Other Operational Procedures
The Owner's Association should maintain a complete and up-to-date set of plans
(as-built drawings) and all changes made to the storm water maintenance devices
over time should be recorded on the as-built plans.
SECTION VI: BUDGET
A. Annual Budget- Water Quality Bio Retention areas 1-12
Annual Inspection & Report
Registered Engineer 1 visit @ 8hrs/visit x $90/hour= $ 800.00
Miscellaneous Visits=
$ 500.00
Maintenance Cost for mowing, seeding fertilizing
And trash removal (2xs annual) $ 600.00
Sediment cost removal (every 5 years) annualized cost $ 600.00
Total Annual Budget (Water Quality Grass Lined Bio Retention areas=
$2,500.00
Page 9 o f 14

B. Total of Construction Cost for Water Quality Grass Line Bio Retention
areas.
Water Quality Bio Retention areas
Bio Retention areas 12 @ $6,000/per = $ 72,000.00
Seeding 664 LF (a, $ 0.50/LF = $ 332.00
Sub-total = $ 72,332.00
Total Construction Cost for Water Quality Grass Line Bio Retention areas:
$72,332.00
Page 10 of 1;~

WATER QUALITY BIO RETENTION AREA INSPECTION CHECKLIST
CEDAR RIDGE SUBDIVISION
INSPECTOR/(S):
WEATHER:
DATE:
TIME:
o WATER QUALITY BIO RETENTION AREA
~ ~-
U
r~
v ° CHECK/CIRCLE
~ ~ CONDITION NOTED OBSERVATION
U
Bio Retention area # Location:
Vegetation
Erosion
Sediment
Trash
Bio Retention area # Location:
Vegetation
Erosion
ACTION
F
d ~ C7
~ rr O t--
"'
a
°z ~ ~ ~
Sediment
Trash
Bio Re tention area #
Location:
Vegetation/ cover

Erosion
Sediment

Trash
Bio Ret ention area #
Location:
Vegetation/ cover

Erosion

Sediment

Trash

Bio R etention area # Location•
Vegetation/ cover
Erosion
Sediment
Trash
Bio R et ention area #
Location:
Vegetation/ cover
Erosion
Sediment
Trash
GENERAL COMMENTS, SKETCHES & FIELD MEASUREMENTS:
Page 11 o f I -1

CEDAR RIDGE SUBDIVISION
WATER QUALITY BIO RETENTION AREAS
PERIODIC INSPECTION, OPERTIAON AND MAINTENANCE REECORDS

DATE
TIME RAIN

(in.) WEATHER

CONDITIONS GENERAL
OBSERVATIONS OR
COMMENTS
RECORDED BY

DATE MAINTENANCE PEIU"ORMED COiVIMENTS RECORDED BY
Pc~~ge 12 o f ~ 1-l

MAINTENANCE AGREEMENT
Project: Cedar Ridge Subdivision
Responsible Party: Cedar Ridce Subdivision Homeowners' Association
Address: 8804 Albright Drive
Ralei h North Carolina
919-614-1733
Monthly Inspection-
A. Visual inspection for signs of erosion after aone-inch or more rainfall event
over a 24-hour period to determine if any appreciable damage occurred which
would require repair to the stormwater device.
B. Remove thrash and debris from inlets and outlets, emergency spillways and
Bio Retention areas.
II. Quarterly Inspections and Maintenance:
A. Same as the monthly described above.
III. Semi-Annually and Maintenance:
A. Same as quarterly inspection
B. Grassing and mowing as required.
C. Reseed or re-vegetate disturbed vegetative areas.
IV. Annual Inspection and Maintenance:
A. Same as quarterly and semi-annual inspections.
B. Registered Engineer inspects and confirms that the stormwater devices are
operating properly and are in good physical condition. A copy of the
inspection reports in Section X of this report shall be submitted to the Central
Engineering Department of the Town of Rolesville. The date set as a deadline
to perform this annual inspection is one year after the date the as-built
drawings were first certified to the Town of RntPC~,;ttP
C. Sediment shall be removed if it is impeding the water flow.
Page 13 o f 1=~

V. General Maintenance:
A. Mowing of Bio Retention areas according to the season. Maximum grass
height of 4-6 inches.
B. In case the ownership of the Impoundment transfers, the current owner shall
within thirty (;0) days of transfer of ownership, notify the Town of Rolesville
Engineering Department, Stormwater Management Division of such
ownership transfer.
C. This property and impoundment is also subject to the Stormwater Operation
and Maintenance Manual and budget filed relative to this project.
D. All trash and debris removal should occur as needed. Bioretention areas
should be inspected for trash and debris monthly.
I, I~-o~?~~ Qp~G.vt c e~ ,for _ ~ `'cat Li~~.2~1T Qt~~,~o ~tyt~~~r4
Q ~~( hereby
acknowledge that I, or my assigns, are the financially responsible party for
maintenance of these water quality Bio Retention areas. I or my assigns will perform
the maintenance as outlined in this document.
•,~'~ r
Signature: ~L(, ~`~"~'t- ~Q Date: 1. ~I/ d
Company/Partnership: C~~1 f ~v'~ ,
I> ~`vfz` ~ ~ .. Q ~,~t~, a Notary Public for the State of (~ ~ ,County
of __~ ~ ~Q~ , do hereby certify that ~ ~b r.~ Q o~ d„ ~. personally
appeared before me this ~ Qday of ~V,, , 200!1, and acknowledge the due
execution of the foregoing instrument.
Witness my hand and official seal,
(SEAL)
KELLY E. PIERCE
NOTARY PUBLIC
WAKf~ COUNTY, N.C.
My Commissbn Expires 4-1$-2i)12.
Notary
My commission expires y ~ ( ' ~ 0 ~ oL
Page 1 ~ o f l -~

~.xp o'1 - 0 0 8 ~ v ~
Aiken & Yelle Associates, PA
AYES Professional Engineers & Land Surveyors
3755 Benson Drive
Raleigh, North Carolina 27609
Phone: [phone] Fax: [phone]
August 7, 2007
NC Division of Water Quality
401 Oversight and Express Permits Unit
Attn: Express Review Staff
2321 Crabtree Blvd
Suite 250
Raleigh, NC 27604-2260
Re: Cedar Ridge Subdivision PCN Submittal
Wake County, North Carolina
Dear Staff:
We have modified the Cedar Ridge Drawings in the following manner:
1 • We have revised Grassed Swale 1 to Bioretention Area 12 per our conversations with Annette
Lucas on August 6`h and 7`i'. We have included in this submittal the bioretention worksheet with
calculations and a revised maintenance manual.
2. We have modified the detail to show that the dissipation pads are not to be included within
surface area of the bioretention cell. Thank you.
If you have any questions regarding the above information please call us at 877-9992
Sincerely
Andrew Klinksiek
Associate Engineer
Aiken & Yelle Associates, PA
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nN~ ~,~„m,,r};,~rca~gp,,,~ch

BIORETENTION
AREA TOTAL AREA
(sq ft) IMP
(sq ft) la Rv WQV
(cu ft)

1 82,900 17,500 0.21 0.240 1,658
2 90,300 34,000 0.38 0.389 2,926
3 52, 700 9, 200 0.17 0.207 910
4 72,100 26,100 0.36 0.376 2, 258
5 82,800 21,800 0.26 0.287 1,980
6 27,900 9,600 0.34 0.360 836
7 33,100 22,600 0.68 0.665 1,833
8 75,800 21,200 0.41 0.420 2,656
9 54, 900 24, 000 0.44 0.443 2, 029
10 18, 700 5, 400 0.29 0.310 483
11 65, 800 22,100 0.34 0.353 1, 935
12 52,600 13,500 0.26 0.281 1,232

Permit No. ~XP L ~ ' UO~ ~ Y~
(to be provided by DWQ)
State of North Carolina
Department of Environment and Natural Resources
Division of Water Quality
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
BIOKETENTION BASIN SUPPLEMENT
This form may be photocopied for erne as an original.
DWO stormwater Management Plan Review
A complete stormwater management plan submittal includes a stormwater management permit application, a
bioretention area supplement for each proposed system, sealed design calculations, a detailed soils report and 2 sets
of plans and specifications showing all stormwater conveyances and system details.
I. PROJECT INFORMATION
Project Name : (~ ~ L(tin~' ~ i is ~ e
Contact Person: _~c.~~l G~ ~e[I~`
Phone Number:
For projects with multiple basins, specify which basin this worksheet applies to: ~ ~Z-
(must match the DA # on the application & plans)
II. DESIGN INFORMATION Attach supporting calculations/documentation. Provide a written soils report
based on actual field investigations conducted by a qualified individual. The soils report should include
informational references to the County soils maps when available. All elevations shall be in feet mean sea level
(fmsl).
Soils Report Summary
In-Situ Soil Type
In-Situ Soil Infiltration Rate
SHWT Elevation
Planting Soil Texture
Planting Soil Infiltration Rate
Basin Design Parameters
Draia:age rurea
Impervious Area
Design Storm
Design Volume
Inlet Velocity
Drawdown Time
Basin Elevations
Temporary Pool Elevation
Planting Elevation
Bottom Elevation
Basin Dimensions
Basin Size
Basin Volume Provided
SWU-]OS 4.07
l~
~ ~' ~ in./hr. (the most restrictive soil layer)
~ ~ 'I` ft. (Seasonal High Water Table elevation)
t~Cam ~G"flLl (mzrst be a sturdy loam, lomny sand, or loam texture)
Z ~ L in./hr.
- ~ q. ~u .-Site ciilu u~wuc uruutu~c tG iice VuSciij
~ 3t ~ G sq.ft. (on-site and off-site drainage to the basin)
1 inch (1.5 inch event for SA waters, 1 inch event for others)
~Z~2 _ c.f. (storage voltnne required)
1. ~ (~,,_ fps
~{ t `~ hours
1 Ali
[~
~~yy ~~~~f+=~gql~lt! -~~~ln.,'l+i''~!~ t;'t~.jF~~.i T119Y9
~r1::1°Y'IVQ ~;i~V ,ri~i~~f''',;t'fA,*f»7'.,'. R~l!t~rli
`z~ Z' ~ fmsl (elevation of the bypass/oartlet structcn-e)
~ ~ I i G fmsl (elevation of the grocuzd surface bottom)
~~ cl ~ u fmsl (elevation of the bottom of the planting media)
~U~~ ft. x ~', ft. = rZ~G sq. ft. (suzfcrce area nt basin bottan)
I ~ ~ ~ c.f.
Page I of 4

Basin Plantings ,~ d
Number of plantings required d ~ ~ Stems (400 sterns per acre of bioreterztion area is required at a minimaun
Total No. of plantings provided ~,}~,} t' ~k -Trees hr' + Shrubs S+t I
(nt least 1 tree for every 3 shrubs)
This system (check one) does does not incorporate the use of an under-drain.
(Under-drains are not allowed for those projects that drain to class SA waters.)
III. REQUIRED ITEMS CHECKLIST
The following checklist outlines design requirements per the North Carolina Stormwater Best Management Practice
Manual and Administrative Code Section: 15A NCAC 2H .1000. These requirements are subject to change in
accordance with the manual and rules.
Initial in the space provided to indicate that the following design requirements have been met and supporting
documentation is attached. If a requirement has not been met, attach written justification. An incomplete
submittal package will result in a request for additional information and will substantially delay final review and
approval of the project.
Applicant's Initials
~_ a. System is located 50 feet from class SA waters and 30 feet from other surface waters.
_ b. No vertical sand bed is proposed.
~ ~~ c. The bioretention area is at least 15 feet wide by 40 feet long.
Stier 21ra~tr~tQ t'frR 1vi..0~N~13h1P Y11l~~~;
~~Q,~ d. A grass buffer strip and sheet flow conditions are provided at the inlet~~ ~~L~ Z ~ ~~ 7
~~_ e. Seasonal High Water table depth is at least 2 feet below the planting elevation surface.
~_ f. Ponding depth of 6-12" is provided.
g. In-situ soils have a minimum hydraulic conductivity of 0.52 inches per hour.
~~ l~ h. An in-depth soils report is provided. (report should include soil t es boring loR, , .ten
suitability for placement of the control system, seasonal high water table, infiltration ate, etc.)
~~
i. The planting soil has a minimum hydraulic conductivity of 0.52 inches per hour. The type and
placement specifications of the planting media are noted on the plans.
~-~~
j. The planting soil meets minimum soil specifications per the latest version of the NCDENR
Stormwater Best Management Practices Manual, including a low phosphonis content to
promote phosphorus removal. (P-Index of 20 to 40 is optimal.) Include a soils test, indicating
~~~~ P-Index, from a certified lab for those projects draining to Nutrient Sensitive Waters.
--~_.__ k. System is designed to draw down the design storage volume to the proposed bottom elevation
under seasonal high water conditions within 24 hours. Draw down calculations are attached.
- ~1~~_ 1. A detailed planting plan, prepared by a qualified individual, is provided on the plans. This lan
shall indicate a variety of suitable species, location, s acing, ~ p
requirements, installation procedures, constniction schedule, eocl preparation, fertilizer
SWU-108 4.07
Page ? of 4

-_• .°• ~ _ m. Type of mulch layer and depth is specified on the plans.
~~`~ n. Plan and section details for the bioretention area are provided. (including dimensions and
elevations)
~~~ o. Plan details for the inlet and outlet structures are provided. (including dimensions and
elevations)
~~ p. All side slopes stabilized with vegetated cover are no steeper than 3:1 (H:V).
=~_ q. A benchmark is provided to determine the sediment accumulation in the basin area.
~_ r. Vegetated filter is provided for overflow and detail is shown on plans (Required minimum
~.,~~~ length is 50 feet for SA waters, 30 feet for other waters).
`-~_ s. Runoff in excess of the desi n volume b
g ypasses off-line systems (bypass detail provided).
~_ t. Plans ensure that the installed system will meet design specifications (constructed or restored)
upon initial operation once the project is complete and the entire drainage area is stabilized.
IV. BIORETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT
Records of maintenance items to include dates, inspector's name, type of maintenance, etc. shall be kept and made
available to Division staff upon request. Maintenance activities shall be performed as follows:
1. Inspect the bioretention area system for soil and mulch erosion, vegetated cover, and general condition after
every significant runoff producing rainfall event and at ]east monthly. Remove trash as needed.
2. Repair eroded areas immediately, re-seed, re-plant, and re-mulch as necessary to maintain good vegetative and
mulch cover.
Remove accumulated sediment as needed to maintain good infiltration. When the filtering capacity diminishes
substantially (e.g., when water ponds on the surface for more than 24 hours), the top few inches of material must
be removed and replaced with fresh planting soil material. Regardless of infiltration capacity, accumulated
sediment in the bioretention basin shall be removed when the depth is reduced to 75% of the original design
depth. ,The system shall be restored to the original design depth without over-excavating. Over-excavating may
cause tnc required water table separation to be reduced and may compromise the ability of the system to perform
as designed. Removed sediment shall be disposed of in an appropriate manner and shall not be handled in a
manner that will adversely impact water quality (i.e. stockpiling near a stormwater treatment device or stream,
etc.).
4. Replace, or add additional mulch as needed. Removal of the old mulch layer before applying the new layer is
recommended every 2 to 3 years.
5. Pnme trees and shrubs and remove debris on an annual basis. Grassed vegetation should not exceed 6 inches in
height.
6. Treat all diseased trees and shrubs whenever needed. Remove and replace all dead and diseased vegetation
considered beyond treatment every 6 months.
7. Replace support stakes yearly (in the spring). Replace deficient stakes or wires whenever needed
SWU-108 4.07
Pace 3 of ~

8. Soil testing shall be conducted annually to determine pH and any accumulation of toxins in the planting media.
Lime or other alkaline substances shall be applied as recommended per the soil test and toxic soils shall be
removed, disposed of properly and replaced with new planting media.
9. All components of the bioretention area system shall be maintained in good working order.
10. If the Division determines that the system is failing, the system will immediately be repaired to original design
specifications. If the system cannot be repaired to perform its design function, other stormwater control devices
as allowed by NCAC 2H .1000 must be designed, approved and constructed.
I acknowledge and agree by my signature below that I am responsible for the performance of the ten 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: _~c~ber+ Pol~nco
Title: ~c'eS`~G~e~t
Address:_gS09 1~fbnc,~,~- t7ri~e -2al~,t~h Nc, 2~1~12
V
Phone: ~~ ~ ~p~ q 1~ 3 3 ~,
Signature:' ~( ,,,rte !~/~~~ ~~
i
Date:
Note: The ega]]y 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.
h ___~ . P ~ Q~`C~Q~. , a Notary Public for the State of ~~~~'~~ o~C'd,~tRCJ4.
County of ~ ~ ~~P ~ , do hereby certify that _ ~ ph~n~ ~ ~~~ ~~ n
personally appeared before me this ~_day of ¢D~ / ,and acknowledge the
due execution of the forgoing bioretention basin maintenance requirements. Witness my hand and official seal,
KELLY E. PIERCE
NOTARY PUBLIC
WAKE COUNTY, N.C.
My C®mmission Expires 4-18-2072.
SEAL
My commission expires ~ ~ ~ ~b`
SwU- 108 4.07
Page 4 of 4

BI012
Date: OS-07-2007
Project: CEDAR RIDGE
Description: Bioretentin Area 12
Hw#38 - Inlet vel ocity
Side slope (H/lv)ha3nel Flow - Trapezoidal Cross Section J°~
----------------------

Discharge Ave. Depth Area
(cfs) vel. (ft) (sq ft) ------
---------
Top Froude
width
--------------
Slope n
-------
Bottom

(ft/s) No.
(ft) (ft/ value
ft) width

----------------
--------
- (ft)

-----3_12- 1.46 0.31 2.14
------------ ----
---
7.85 0.49
----------------
-------------
.00500 .0300
-------------
-------
6.00
-------
Page 1

Bioretention Area 12
RECARGA 2.X
Date: 07-Aug-2007 13:38:25
Output File: Bioretention Area 12.txt
Number of time steps= 289
CPU elapsed time (s)= 0
INPUT TERMS
%Impervious= 26
Pervious CN= 74
Facility Area (sf)= 1250
Trib. Area (AC)= 1.21
RATIOimp2rg= 10.9632
RATloperv2rg= 31.2029
LAYER DEPTH (in) Ksat (in/hr) TEXTURE
Depression 12 --- ---
Root Zone 24 4.14 1
storage 4 10.00 1
Native --- 1.28 3
Init. Cond.: suction head (in)= -39
Max. underdrain flow (in/h r)= 0. 008
underdrain diam (in)= 4.003
WATER BALANCE TERMS
volume(ac-ft) Depth (in) %of Inflow
Inflow 0.10 1.01 100.00
Runoff 0.01 0.06 6.33
Recharge 0.05 0.50 49.78
Evaporation 0.00 0.01 0.54
underdrain 0.05 0.50 49.37
Storage -0.01 -0.06 -6.02
Infiltrated 0.10
Precip. 2.37
Imp. Inflow 0.05 2.23 48.50
Perv.Inflow 0.03 0.54 33.18
Basin Stayon(in) -42.25
Total Stayon(in) 1.81
Mass Balance Checks:
vinsoil=input-roff-dvh
vinsoil (ac-ft)= 9.732047e- 002
vinf difference (%)_ -0.0
vrechargl=inf-et-dsws
vrechar~l (ac-ft)= 5.171609e- 002
vrech difference (%)_ -0.0
dvsoil=inf-rech-et
dvsoil= 4.503863e-002
dvsfce (ac-ft)= O.000OOOe+000
dvs2=input-roff-inf
dvs2 (ac-ft)= 4.608371e-017
PLANT SURVIVABILITY TERMS
total time ponded (h)= 7.5
max time ponded (h)= 7.5
total time Rz saturated (h)= 7.8
total time Rz at wilting point (h)= 0.0
total time Tz saturated (h)= 8.8
max time Rz saturated (h)= 7.8
max time Rz at wilting point (h)= 0.0
max time Tz saturated (h)= 8.3
near saturated times for simulation = 2
19.0 7.8
20.3 0.0
wilting point times for simulation= 0
0.0 0.0
ponded times for simulation= 1
19.0 7.5
overflow times for simulation= 0
Page 1