20001195 Ver 6_More Info Received_20081030

ONE COMPANY
Many Solutions"
00-10isv ?6 Transmittal
Attention: DWQ Date: 10/29/08 Job No: 100062-75476-018
To: Joseph Gyamfi Phone: [phone]
Regarding CDIA SWMP
We are sending you: L? Attached U Under separate cover via _ the following items
? Shop drawings ? Prints ® Plans ? Samples ? Specifications
? Copy of Letter ? Change Order ® Reports ? CDs ? Other
Cnnies Date Nn. Descrintion
2 10/29/08 1 Revised BMP Operation and Maintenance Plan
2 10/29/08 2 Revised Bioretention Cell Supplement
2 10/29/08 3 Revised Bioretention Cell Calculations for Pipe Diameter
2 10/29/08 4 Revised Sheet 14 of SWMP Colored Plans

These are transmitted as checked below:
® For approval ? Approved as submitted
® For your use ? Approved as noted
® As requested ? Returned for corrections
? For review/comment ? Other
? Forbids due
® Resubmit 2 copies for approval
? Submit copies for distribution
? Return corrected prints
? Prints returned after loan to us
i?
O C T 3 0 2008
DENR WATER QUALITY
?yE LANDS 00 STORMWATER BRANCH
Remarks
If enclosures are not as noted, please notify us at once

W:109027_CDIA Well Talbert & Bright109027-43419-018_NewRunway15.00 Project Data_ Reference Data1SWMP1Revised SWMP\App_pack\SWMP July 20081Transmittal
Form.doc
HDR Engineering, Inc. of the Carolinas I 128 S. Tryon Street, Suite 1400 I Telephone [phone]
Employee-owned Charlotte, NC 28202-5004 Fax [phone]
?.?+ e' ? .. ? •?
HMNR
Permit No:
(to be assigned by DWQ)
pF W n rFH
{ O
F
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
BIORETENTION CELL SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part 111) must be printed, filled out and submitted along with all of the required information.
I. PROJECT INFORMATION
Project name CDIA T 11P area Est of 2nd Parallel Runway
Contact name Ron Geiger
Phone number 704-338-6825
Date October 29, 2008
Drainage area number Old Dowd Road A2
II. DESIGN INFORMATION
Site Characteristics
Drainage area 88;419.23 ft2
Impervious area 64,193.00 ft2
Percent impervious 72.6%0 %
Design rainfall depth 1.00 inch
Peak Flow Calculations
1-yr, 24-hr runoff depth 2.77 in
1-yr, 24-hr intensity 0.12 in/hr
Pre-development 1-yr, 24-hr peak flow 8.90 ft3/sec
Post-development 1-yr, 24-hr peak flow 17.70 ft3/sec
Pre/Post 1-yr, 24-hr peak control 8.80 ft3/sec
Storage Volume: Non-SR Waters
Design volume 7,083.77 ft3
Storage Volume: SR Waters
Pre-development 1-yr, 24-hr runoff ft3
Post-development 1-yr, 24-hr runoff ft3
Minimum volume required ft3
Volume provided ft3
Cell Dimensions
Ponding depth of water 12.00 inches
Ponding depth of water 1.00 ft
Surface area of the top of the bioretention cell 7200.00 ft2
Length: 120.00 ft
Width: 60.00 ft
-or- Radius ft
Soils Report Summary
Drawdown time, ponded volume 8.00 hr
Drawdown time, to 24 inches below surface 16.00 hr
Drawdown time, total: 24.00 hr
In-situ soil:
Soil permeability 0.60 in/hr
Planting media soil:
Soil permeability 1.50 in/hr
Soil composition
% Sand (by weight) 85%
% Fines (by weight) 10%
% Organic (by weight) 5%
Total: 100%
Phosphorus Index (P Index) 20 (unitless)
Form SW401-Bioretention-Rev.3
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
oc? 3°1
W???g?CN
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OK
Note: Phosphorous is not a concern in this area.
Part III, Page 1 of 2
Permit No:
(to be assigned by DWQ)
Basin Elevations
Temporary pool elevation 679.00 fmsl
Planting elevation (top of the mulch) 678.00 fmsl
Bottom of the cell 675.80 fmsl
Planting depth 2.20 ft
Depth of mulch 2.00 inches
SHWT elevation 670.00 fmsl
Are underdrains being installed? Y (Y or N)
How many clean out pipes are being installed? 8
What factor of safety is used for sizing the underdrains? (See 2.00
BMP Manual Section 12.3.6)
Additional distance between the bottom of the planting media and 1.00 ft
the bottom of the cell to account for underdrains
Bottom of the cell required 674.80 fmsl
Distance from bottom to SHWT 4.80 ft
Type of bioretention cell (answer "Y" to only one of the two following
questions):
Is this a grassed cell? Y (Y or N)
Is this a cell with trees/shrubs? N (Y or N)
Planting Plan
Number of tree species 0
Number of shrub species 0
Number of herbaceous groundcover species 1
Additional Information
Does volume in excess of the design volume bypass the Y (Y or N)
bioretention cell?
Does volume in excess of the design volume flow evenly distributed N (Y or N)
through a vegetated filter?
What is the length of the vegetated filter? N/A ft
Does the design use a level spreader to evenly distribute flow?
Is the BMP located at least 30 feet from surface waters (50 feet if
SA waters)?
Is the BMP localed at least 100 feet from water supply wells?
Are the vegetated side slopes equal to or less than 3:1?
Is the BMP located in a recorded drainage easement with a
recorded access easement to a public Right of Way (ROW)?
Inlet velocity (from treatment system)
Is the area surrounding the cell likely to undergo development in the
future?
Are the slopes draining to the bioretention cell greater than 20%?
Is the drainage area permanently stabilized?
Pretreatment Used
(Indicate Type Used with an "X" in the shaded cell)
Gravel and grass
(811nches gravel followed by 3-5 ft of grass)
Grassed swale
Forebay
N (Y or N)
OK
OK
OK
OK
OK
OK
OK
More species are recommended.
More species are recommended.
More species are recommended.
OK
Excess volume must pass through filter.
Note: excess volume passes through a grassed overflow weir.
Show how flow is evenly distributed.
Y (Y or N) OK
Y (Y or N) OK
Y (Y or N) OK
Y (Y or N) OK
ft/sec
N (Y or N) OK
N (Y or N) OK
Y (Y or N) OK
N
OK
N
V
Form SW401 -Bioretention-Rev. 3 Part 111, Page 2 of 2
CDIA SWMP October 29, 2008
Area West of 2nd Parallel Runway HDR Engineering, Inc
of the Carolinas
Bioretention Calculations for Drainage Area A2 only
Volume Calculations
_ Impervious portion of Drainage Area _ 1.47
IA Total Drainage Area 6.098 - 0.24
R„ = 0.05 + 0.91A = 0.27
Total Drainage Area = 7.31 ac
Volume = 3630*Ro*R„*A = 7083.77 cft
Dimentions of Bioretention Cell = 60 x 120 sqft
Ponding Depth = 1 ft
Volume = 7200 cft
Drawdown Calculations
Total volume to be treated 7084 cft
Permability of Soil (POS) 1.5 in/hr
Surface Area of Soil (SA) 7200 cft
Draw down time for ponded area
V to be treated
PoS * SA of Soil
7084 _ 7.9 hrs
0.125 7200
Drawdown Time to 24 in below surface
1 ft of Ponding Depth into soil is 8 hrs
2 ft of soil is 16 hrs
Total Drawdown time 24 hrs
CDIA SWMP
Area West of 2nd Parallel Runway
Underdrain Sizing
Q in Volume
Time
7084 cft
24 hr
V = 0.08 cfs
T
Using Orfice Equation
CD
D
Area
Havg
Q out
0.4
4 in
0.09 sqft
1.5 ft
Cd * A * SQRT (2gH) = 0.19 cfs
Using BMP manual
D = (16*Q*n /( S 110. 5)) 113/8
n 0.011
S 0.005
D 0.55 in
Using a 4 in underdrain exceeds the flow into the underdrains by 0.11 cfs.
NCDENR recomends two 4 in underdrains, the plan includes 4 underdrains.
Therefore, no backwater will occur.
October 29, 2008
HDR Engineering, Inc
of the Carolinas
CHARLOTTE - DOUGLAS INTERNATIONAL AIRPORT
STORM WATER MANAGEMENT PLAN
Operation & Maintenance Plan
for
Area West of 2nd Parallel Runway
Prepared by Talbert Bright Inc.
In association with HDR Engineering
Revised October 29, 2008
The following Operation & Maintenance Plan (OMP) has been prepared in compliance with
NCDENR DWQ 401 permitting requirements for the construction and operation of the project
entitled, Taxiway Victor Old Dowd Rd Relocation and Wallace Neel Road Relocation" located at
Charlotte/Douglas International Airport (CDIA), Charlotte, North Carolina. This project involves the
construction of a new parallel taxiway west of the existing terminal facility, Old Dowd Road
Relocation and the relocation of Wallace Neel Road. The OMP describes CDIA maintenance
responsibilities for the monitoring, cleaning, and necessary maintenance of the following Best
Management Practices (BMPs) for these new facilities:
1. Grassed Swales
2. Filter Strips
3. Extended Dry Detention Basins
4. Pavement Sweeper with Vacuum
5. Bioretention Basin
?Wx 0 T 3 0 2008
U?F1?t -'?f T??M?ejpSER BRANGH
V1f `• W'?pS ?,Plo S
OPERATION AND MAINTENANCE AGREEMENT
I acknowledge and agree by my signature below that I am responsible for the
performance of the six maintenance procedures listed in this OMP. I agree to notify
DWQ of any problems with the system or prior to any changes to the system or
responsible party.
Print name: T. J. Orr
Title: Aviation Director
Address:5501 Josh Birmingham Pkwv. Charlotte, NC 28208
Phone [phone]
Signature:
Date:
I, , a Notary Public for the State of North
Carolina, County of Mecklenburg, do hereby certify that
personally appeared before me this
day of , 2008, and acknowledge the due execution of the forgoing
Operation & Maintenance requirements. Witness my hand and official seal,
SEAL
My commission expire
1.0 Grassed Swale
1.1 Description
Grassed swales typically are used in residential and commercial developments as well as
along highway medians as alternatives or enhancements to conventional storm sewers. Swales
remove pollutants from stormwater by filtration through grasses and other vegetation, settling,
and infiltration through soil. Grassed swales are occasionally enhanced with check dams to retain
water and promote infiltration.
1.2 Monitoring
The vegetation in the grassed swale should be inspected at least twice per year.
1.3 Maintenance
Maintenance of grassed swales involves grooming the vegetation and occasionally removing
trash. Routine mowing is required for turf grasses. Grass shall be cut no lower than 5 inches. In
addition, the grass should be allowed to grow to the maximum height consistent with the species
and aesthetic requirements. The frequency of trash removal depends on the location and
attractiveness of the swale as a disposal site. Excessive sediment should not accumulate if erosion
is controlled adequately upstream. However, if excessive siltation occurs, the sediment must be
removed periodically (no less than once annually). Sediment that accumulates in the swale may
be prone to resuspension during large storm events and can kill the grass. Sediment should be
removed when it reaches a depth of 4 inches or when it covers the grass. Additional annual
maintenance activities are as follows:
¦ Repair erosion and regrade the swale to ensure that runoff flows evenly in a thin sheet
through the Swale.
¦ Revegetate the Swale as needed to maintain a dense growth.
1.4 Schedule
Activities Frequency
Inspect vegetation in grassed Swale Bi-Annually
Remove debris As needed
Remove sediment As needed, (annually or when it reaches a
depth of 4 inches or covers the grass)
Repair erosion Annually
Re grade and reve etate the swale As needed
Mow grassed Swale Routinely for turf grasses to maintain height
2.0 Filter Strip
2.1 Description
Filter strips are uniformly graded and densely vegetated sections of land, engineered and designed
to treat runoff from and remove pollutants through vegetative filtering and infiltration. Any
natural vegetated form, from grassy meadow to small forest, may be adapted for use as a filter
strip. However, the vegetation must have dense foliage and thick root mat to be effective. Filter
strips are designed to accept runoff from overland sheet flow from upgradient development. The
strips trap sediment and sediment-bound pollutants. Because they "disconnect" impervious
surfaces from storm sewers and lined channels, filter strips reduce effective imperviousness and
help reduce peak discharge rates by increasing travel time and by increasing abstractions from the
total flow. Filter strips typically include some method of spreading the runoff as sheet flow.
2.2 Monitoring
During the first 1 or 2 years after construction, filter strips should be inspected for proper
distribution of flows and signs of erosion during and after major storm events. After the first 1 or
2 years, the strip may be inspected annually or biannually. If evidence of erosion exists, the
eroded areas should be filled in and reseeded. The cause of the erosion should then be determined
and, if possible, eliminated.
2.3 Maintenance
With minimal maintenance, filter strips can be effective indefinitely. However, strips that
are not maintained properly may quickly become nonfunctional. Maintenance involves routine
activities such as mowing, trimming, and replanting when necessary. Strips that are used for
sediment removal may require periodic regrading and reseeding of their upslope edge because
deposited sediment can kill grass and change the elevation of the edge such that the stormwater
no longer flows through the strip in thin sheets. Maintenance requirements are as follows:
¦ Remove deposited sediment, especially from the upstream edge, to maintain original
contours and grading.
¦ Repair gullies and rills that form and regrade the filter strip to ensure that the runoff flows
evenly in a thin sheet over the filter strip.
¦ Reseed and regrade the filter strip to maintain a dense growth of vegetation, especially if
the strip has been used for sediment control.
¦ Mow filter strips vegetated with grasses and harvest the clippings two to three times a
year 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.
¦ Keep the filter strip free of litter.
¦ Evaluate the runoff from adjacent areas to determine if it is providing enough water and
nutrients or if additional irrigation and fertilizer are needed.
¦ Perform periodic aeration of the soil if excessive compaction is interfering with
maintaining a good vegetative cover.
¦ Test the soil pH and compare it to the recommended pH for the specific vegetation. Add
lime if indicated.
2.4 Schedule
Activities Frequency
Inspect filter strips and level spreaders For the first two years during and after major
storm events
After first two ears annually or biannually
Remove deposited sediment Annually, as needed
Repair gullies and rills that form As needed
Re grade the filter strip As needed
Reseed and re grade the filter strip As needed
Mow filter strips vegetated with grasses Regularly to maintain height
Harvest clippings Two to three times per year
Remove debris As needed
Evaluate runoff from adjacent areas As needed
Perform periodic aeration of the soil As needed
Test the soil pH As needed
3.0 Extended Dry Detention Basins
3.1 Description
As the name of this BMP implies, these basins are typically dry between storm events. To qualify
as a BMP, dry basins should incorporate extended detention of runoff derived from small rainfall
events. In dry ED basins, a low-flow outlet slowly releases water retained below the primary
outlet device over a period of days. This BMP can be applied in low-density residential,
industrial, and commercial developments where sufficient space is available. The primary
purpose of dry ED basins is to attenuate and delay stormwater runoff peaks. The dry ED basins
for this project will include a sand filter bottom with a subsurface piping system for removal of
the filtered water to enhance the pollution removal of the dry ED basin.
3.2 Monitoring
The facility should be inspected annually to verify that the facility is operating as designed
and to schedule any required maintenance. If possible, inspections should occur during wet
weather to verify that the facility is maintaining desirable retention times.
As a minimum, the following items should be included in the annual inspection:
¦ Embankment settling, woody growth, animal burrowing, and signs of piping
¦ Condition of grass cover on the embankment, basin floor, and perimeter of the basin
¦ Riprap displacement or failure
¦ Principal and emergency spillway to confirm that they meet design plans for operation
¦ Outlet controls, debris racks
¦ Outlet channel conditions
¦ Safety features
¦ Access for maintenance equipment
¦ Clogging of the low-flow orifice and sub-drainage piping
• Drainage of the low-flow channel
¦ Sediment accumulation in the sand media
3.3 Maintenance
Maintaining turf grass on the tops of berms and on the exterior slopes of embankments is
advisable to facilitate access to the facility and inspection of the embankment. Any seedlings or
planting should be removed at the earliest opportunity and the disturbed areas should be stabilized
properly. Control of woody vegetation will require periodic mowing and a policy of not allowing
plantings on these facilities. The facility should be managed with grass no shorter than 6 to 8
inches and be mowed at least twice annually.
Root voids and animal burrows should be plugged with material similar to the surrounding
materials, and capped just below grade with stone, concrete, or other material. If plugging the
burrows does not discourage burrowing animals from returning, further measures should be taken
to remove the animal population or to make critical areas of the facility unattractive to them.
Dry ED basins should have enough volume to account for sediment accumulation over time.
Trash and debris can accumulate quickly in dry ED basins, requiring frequent cleaning, at least
twice annually. The accumulated sediment, mud, sand, and debris must be cleaned out with earth-
moving equipment and disposed of properly, on average, every 2 to 10 years or when the basin
has lost approximately 20 percent of its capacity. Caution should be taken not to damage the sub-
drainage system. Once these materials are removed, the disturbed areas should be stabilized and
revegetated immediately; otherwise, sediment will move to downstream areas. Freshly seeded
areas should be protected with an erosion mat that has been securely staked in place to prevent
flotation. In many cases, sodding offers the best approach to stabilization after removal of
sediment and debris.
The sand filter bottom and sub-drainage piping system should be inspected bi-annually for
uniform slope and depth conditions in the sand. The bottom of the basin must be accessible for
maintenance. The access path should be a minimum of 10 feet wide, have a maximum slope of
5H:1 V. Steeper slopes may result in rutting and require more access path maintenance.
3.4 Schedule
Activities Frequency
Inspect the dry ED basins Annually (once during rain event, once during
d period)
Maintain turf grass As needed
Remove seedlings or planting As needed
Mow Biannually (as a minimum to maintain height
Unplug root voids and animal burrows As needed
Remove debris Biannually
Remove sediment, mud, sand, and debris -
Every 2 to 10 years or when the basin has lost
approximately 20 percent of its capacity
Stabilize and reve etate As needed
Maintain access path As needed
4.0 Pavement Sweeper with Vacuum
4.1 Description
Pavement sweeping and vacuuming includes use of self-propelled or walk-behind equipment to
remove sediment from streets, roadways, and other pavements. Sweeping and vacuuming
prevents sediment from the project site from entering storm drains or receiving waters.
4.2 Monitoring
Regular inspection of the pavement is critical. Make sure that the sweeper does not sweep up
anything hazardous, since it might cause damage to the machine. A trash and leaf litter pick-up
program will be conducted weekly to avoid leaf piles and decomposition of the leaves and other
trash in the storm drain inlets.
Scheduled sweeping will occur twice per week and immediately after special events like
installation of lighting in pavement, pavement closures, and following grass cutting operations.
Sweeping of paved surfaces will occur prior to rain events greater than 1" rainfall depth,
irrespective of whether the pavement had been swept twice within a week or not, if upon 24 hours
notice that a qualifying rain event is imminent. Therefore, the sweeping prior to a rain event shall
be done if (a) the magnitude will be 1" or greater and (b) there had not been any sweeping activity
in the past 24 hours.
Management of the debris from sweeper hoppers shall include collecting and taking debris to a
secure temporary storage area or directly to its permanent disposal site. Do not empty sweeper
hoppers temporarily onto areas near storm drains or surface water bodies or where wind or rain
could re-entrain or scatter the debris. Avoid conducting sweeping operations during rainstorms.
Sampling and testing procedures will be conducted to evaluate the effectiveness of vacuum
sweeping with respect to the pollutant removal credits assigned to it. A quarterly report shall be
submitted to DWQ for review. Debris collected will be weighed prior to final disposal and logged
for inclusion in the DWQ report. Prior to initial operation, a testing procedure will be established
to identify the sweeping protocol for debris removal and to establish the expected removal
efficiency from this practice. The testing procedure and its results will be submitted to DWQ for
review and approval.
4.3 Maintenance
Inspect pavement prior to forecast of extended rain events, weekly during the rainy season, and at
monthly intervals during the non-rainy season. More frequent removal may be required in some
jurisdictions, if considerable sediment/debris is observed during inspection. Be careful not to
sweep up any unknown substance or any object that may be potentially hazardous. Adjust
brooms frequently; maximize efficiency of sweeping operations. After sweeping is finished,
properly dispose of sweeper wastes at an approved dumpsite.
4.4 Schedule
Activities Frequency
Inspect pavement Monthly
Sweep pavement Twice per weekly for all paved surfaces, after
special events prior to reopening, and prior to
qualifying events
Submittal of sweeping logs to DWQ Quarterly
Pick a trash and leaves Weekly
Monitoring/logging of debris collected After each sweeping event
Inspect and Adjust brooms Quarterly
Dispose of sweeper waste After each sweeping event
Bioretention Basins
5.1 Description
Bioretention Basins treat stormwater runoff on development sites commonly located in
densely site constraints such as parking lot islands or within small pockets of land uses.
Surface runoff is directed into shallow, ground depressions. These depressions are
designed to integrate many of the pollutant removal methods that function in natural
ecosystems. During rainstorm events, runoff ponds above the mulch and soil in the
bioretention system then filters through the mulch and prepared soil mix. Typically, the
filtered runoff is collected in a perforated underdrain and diverted to the storm drain
system.
5.2 Monitoring
After the bioretention basin is established, an inspection will be conducted once a month
and within 24 hours after every storm event greater than 1.0 inches.
5.3 Maintenance
Like any landscape feature, bioretention areas must be pruned, mulched, and initially
watered and limed. Grassed bioretention cells are usually mowed. Because plants are an
important investment and essential to the aesthetic appeal of bioretention systems, they
need to be established as quickly as possible. The need for rapid establishment requires
bioretention cells to be limed, if indicated by a soil test. Additionally, plants may need to
be spot-fertilized to ensure growth and survival in soils. Watering the plants every 2 to 3
days for a couple of months helps ensure vegetation survival. The frequency of these
tasks varies seasonally, with more frequent maintenance required in summer than in
winter. Maintenance to bioretention basins include occasional removal of mulch and the
top layer of fill soil. Since clogging occurs frequently at the top of the soil column, the
bioretention basins rarely need to be completely excavated.
• 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.
• Inspect flow entrances, ponding area, and surface overflow areas periodically.
Replace soil, plant material, and/or mulch in areas where erosion has occurred.
If sediment is deposited in the bioretention facility, immediately determine the
source, remove excess deposits, and correct the problem.
• Occasional pruning and removal of dead plant material may be necessary.
Periodic weeding is necessary until groundcover plants are established.
• Replace mulch annually in bioretention facilities where heavy metal deposition is
likely (e.g., 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.
A
• Soil mixes for bioretention facilities are design to maintain long-term fertility and
pollutant processing. Therefore, the capability tests should be conducted in 20
years for metal toxicity. If this is above the standard allowance then the soil
should be replaced.
• Heavy equipment will NEVER be driven over the bioretention basin.
• Once a year, a soil test of the soil media will be conducted.
After the bioretention basin is established, inspection will occur 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.
5.4 Schedule
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
Activities Frequency
Mowing 2-12 times / year
Mulching 1-2 times / year
Mulch removal 1 time / 2-3 ears
Watering 1 time / 2-3 days for first 1-2 months.
Sporadically after establishment
Fertilization 1 time initial)
Misc. upkeep 12 times / year
Inspect basin and perimeter 12 times / year and after 1 inch storm events
Forebay Clean out of sediment/debris 1 time / year for sediment buildup, erosion,
weeds
Soil Inspection Annual soil test for heavy metals and pH
Underdrain clean out 1 time / year for clogging, and cracks
Inspection of Receiving Water Channel 1 time / year for bed erosion or other signs of
damage that has occurred at the outlets.

w d
O
TRANSVERSE VIEW LONGITUDINAL VIEW
SEE DETAIL A
SECTION C-C FOR ENLARGEMENT SECTION D-D
TIE IN ~ TIE IN
C WEIR AT END OF
4" DIA, CLEAN 12" BASIN ~
OUT PIPES 4" DIA. CLEAN 5' O
OUT PIPES Vf
4" WEIR AT END OF BASIN 0 WITH SCREW CAPS 4"
PONDING
3 PONDING 3 n 1~ n 1 12 12 12"
3~~ ~ t
3n ` ~ 3
FILL IA 2" MULCH 85% SAND 2" MULCH
10% FINE
5% ORGANIC
2' FlLL MEDIA 2' FILL MEDIA )IA
GEO FILTER f- N r~ d' to
4 r FABRIC ujc ~'4 WASHED SAND; ~•3 • 4 DIA.~~'~ ~ . :.i; .,j` °"zf;'•~;~'.t.; .y~; .Y 4" SAND.~~:`•' .„ti..
2n s, "f,•
8" N0. 57 STONE 8" STONE N O
2" O 0 to (v
4" DIA. UNDERDRAIN 4" INV. 674.0 ~ _
12' 12' 12' 12' 12' DISCHARGE PIPE ~ U
3 3' 4" DIA. UNDERDRAIN ~Q ~ N d DISCHARGE PIPE
60' 120' 0.5~ MINIMUM SLOPE
D } ~ O m w Z~ m W
W W N
C -C Z W W Z Y- ~ ~ ~ v w
SECTION B-B F-
0 ~ 0~. 0 U ~
60' BIORETENTION WIDTH
FILTER STRIP ENTRANCE LEVEL SPREADER -40' BYPASS / WEIR
5'

\ 3 ~ TIE BYPASS CHANNEL ~ F'"
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~ 3 / 3 \ - EXTEND TO BYPASS CHANNEL ~O
~1
~ ~ / ~ \ \ ~ oC
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I I .
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I--------------------I WIDTH, 2' DEEP, 2:1 SIDE SLOPES,
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SIDE '2 SIDE DIM., ~0 ~
.1 i ~ r
DETAIL A \ s
\ \ 90 ~ ~ ~ ~ ~d_! BYPASS WEIR
_ 18 RCP ~p0 ~ ~~Qa\ ~ 40 LF LONG, 5 FT TOP,
~ ~ t WIDTH, 3:1 SIDE SLOPES
d- : a ° lp \ EXISTING ROAD EMBANKMENT `--~8..~ ~ r, .
~ \ \
0 ED ,
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r~Q.~ ~ ~ ~ ~ ~ ~ ~ Z
\ \ ~ , 696 , Z
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8 12 WQ VOLUME \ \
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\ -ELEV. 678.0 ~ \
MULCH \ FILTER STRIP ENTRANCE/LEVEL SPREADER - \ ~ ~ Q
3 TO BIORETENTION 0~ ~ ~ ~ ~
~ ~ ~ W {'1
FILL MEDIA ~ 7 ~ ~ ~ \ ~ z ~ ~ ~ ~ o
1 0 \
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NOTES:
STONE 1. CONTRACTOR TO INSTALL STONE DITCH CHECKS AS DIRECTED BY
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GROUNDWATER -ELEV. 874.8 INSPECTOR, FOR EROSION CONTROL. ELEVATION 2. CONSTRUCT ALL DIVERSION DITCHES PRIOR TO INSTALLATION OF ~ ~ W ~ o
BELOW s7o.o 0 BIORETENTION BASIN.
3. LOCATION OF 72" RCP OUTFAIL CHANNEL TO BE COORDINATED
WITH FUTURE RAILROAD IMPROVEMENT PLANS. ~ ~ Q o
4. UNDERDRAIN PIPES TO BE SCHEDULE 40 PVC. DRAIN PIPES LEGEND ~ v ~
BETWEEN CLEAN-OUTS SHALL BE PERFORATED. ALL OTHER 0~. ~
r ~ PIPES SHALL BE SOLID WALL. << _ ~ FILTER STRIP 1 (FS) 1 2 8 6
FLTER STRIP 2 (FS) w
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FILTER STRIP 3 {FS) w
Q 7 g GRASS SWALE {GS) J
EXTENDED DETENTION BASIN
_1 ~ BID-RETENTION BASIN TALBER &BRIGHT
~~1'~ Ir~n~~r~ n
10 is I AwAA. t1 !l ENCENEEMO & Pd.ANN1NO CONSULMM
LEVEL SPREADER 50 25 0 50 100 150
~ PROPOSED PAVEMENT aoc~ =!S a 14 LH OCT 0 2008 4944 PARKWAY PLAZA BOULEVARD, SUM 350
o coo oc~ SCALE IN FEET HOR Engineering, Inc. f CHARIArM NORTH CAW124A 28217
of the Carolinas WETLANDS AND STORmw TER BBC,, PHONE: 7M264070 FAX: [phone]
1 "=50' www.talbertandbright.com 14 128 S Tryon Street, Suite 1400 1 Charlotte, NC 28202