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Stormwater Management Report
Submitted to:
NCDEQ
Prepared for:
Biscuitville
NC HWY 24/87 & Percy Blvd.
Town of Cameron /Spout Springs —Township, NC
CSD Project No: BIS -1803
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Prepared by:
COMMERCIAL SITE DESIGN, PLLC
8312 Creedmoor Road
Raleigh, North Carolina 27613
September 6, 2018
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Table of Contents
ProjectDescription.........................................................................................................................
2
AdjacentAreas................................................................................................................................
2
ExistingConditions.........................................................................................................................
2
ProposedConditions.......................................................................................................................
2
Proposed Stormwater Mangement Requirements.........................................................3
Calculation Methodology.....................................................................................3
Maintenance....................................................................................................
3
Listof Appendices: ...........................................................................................................................
AppendixA - Maps...........................................................................................................................
SoilsSurvey Map..............................................................................................................................
FIRMPanel.......................................................................................................................................
USGSTopo Map..............................................................................................................................
Pre Development Impervious Area Map..........................................................................................
Post Development Impervious Area Map.........................................................................................
Appendix B - Deed Restrictions & Protective Covenances................................................
Appendix C - Off-site Supplement Form & Stormwater Permit Application ...........................
Appendix D - SHWT & Soils Report .........................................................................
Appendix E - Permeable Pavement Details and Specifications....................................................
1
Biscuitville — NC FiWY 24/87 & Percv Blvd.
Town of Cameron /Spout Springs - Township, NC
BIS -1803
Project Description
This report addresses expected stormwater runoff and water quality for the proposed development of a
Biscuitville restaurant. The property is located on the corner of NC Hwy 24/87 and Percy Blvd.
at the coordinates 35° 15'21.2076" N, 79° 2' 10.5756" W. The site is a vacant property. The total site
area is 1.06 acres and there is no existing impervious. After proposed development, the site will have
28,030sf /0.64 acres impervious and 1,794sf /0.04 acres of permeable paving.
Adjacent Areas
The site is a corner lot with commercial uses on adjacent parcels. Limits of disturbance for the
development will remain onsite with the exception of utility connections.
Existing Conditions
The runoff on-site sheet flows from the south to the northeast and an existing storm drainage system.
The proposed development will maintain existing drainage patterns.
Site Area =1.06 acres
Existing Impervious = 0.00 acres
Existing Open Space = 1.06 acres
The NRCS Soils Survey mapping included in Appendix A shows that the soils on the site are:
CaB — Candor sand, belonging to hydrologic soil group A.
Proposed Conditions
The proposed construction will consist of one single -story 2,982sf building for a Biscuitville restaurant,
curb islands and associated parking. Majority of stormwater runoff will enter into a conveyance system
on-site that outlets into an existing stormwater detention pond in the rear of property. The stromwater
run-off in the front of building sheet flows to a permeable pavement parking area along right-of-way.
Site Area =1.06 acres
Proposed Impervious = 0.64 acres
Proposed Open Space = 0.42 acres
2
Biscuitville — NC HWY 24/87 & Percy Blvd.
Town of Cameron /Spout Springs - Township, NC
BIS -1803
Proposed Stormwater Management Requirements
The existing stormwater pond in the rear of site will be used to meet stormwater requirements. The
existing pond was approved for a maximum built upon area of 33,106sf for this site under Permit No.
SW6111206. (See Appendix B for a copy of Deed Restrictions and Protective Convenances details.)
Note: Proposed parking exceeds the required parking for this project therefore a portion of parking
area is permeable pavement. (See Appendix E and Site Plans for details)
Calculation Methodology
• Soils data for the site was taken from the NRCS USDA web soil survey website
(http://websoilsurvey.nres.usda.gov/). Please reference the miscellaneous site data section within
this report for additional information.
• The on- and off-site topography used in the analysis is from a field survey by Commercial Site
Design.
Maintenance
Frequent, thorough, and consistent inspections and maintenance are critical to the successful operation
of the stormwater control measures. Inspections reveal the operational status of the system and identify
needed maintenance actions. The individuals responsible for inspecting and maintaining the stormwater
system should thoroughly understand the stormwater control measures and processes. The type and
frequency of maintenance for a specific stormwater system is determined by inspection results and the
maintenance schedule for each stormwater device being proposed. Maintenance should be performed in
accordance with system design information and safety procedures. Performing timely maintenance is
important in preventing system failure and will be less expensive in the long-term.
Construction Maintenance
During construction, the contractor must implement a self-monitoring program that includes a written
site evaluation of all erosion control measures after each measurable storm event, and at least one time
per week, in accordance with the requirements in the stormwater manual. All measures and controls
must be repaired and maintained in proper operating condition.
Post -Construction Maintenance
After all construction activity has been completed, underground detention maintenance is the
responsibility of the property owner.
Biscuitville — NC HWY 24/87 & Percy Blvd.
Town of Cameron /Spout Springs - Township, NC
BIS -1803
-54
Biscuitville — HWY 24/87 & Percy Blvd.
Cameron, NC
BIS -1803
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PROJECTNO.
BIS -1803
FILENAME:
BIS1803-EXA
SCALE.
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DATE:
8/23/2018
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PRE- IMPERVIOUS EXHIBIT
BISCUITVILLE
1608 NC 24-87
CAMERON, NORTH CAROLINA
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ORAINAQE EASEMENT
MAP NUMBER W12-150
M NUMBERW13-259
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DEED ROOK 3087,P
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SITE DESIGN
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\ \ YO REMAINING PERVIOUS PAVEMENT = 14, 038 SF OR 0.32ACRES
CONCRETE SIDEWALK= 1,099 SF OR 0.03 ACRES
N80 -1630-W
14.73'
\ I \ v ® BUILDING IMPERVIOUS= 2, 982 SF OR 0.03ACRES
TOTAL IMPERVIOUS 26017 SF OR 0.64
PROJECTNO. BIS -1803 POST IMPERVIOUS EXHIBIT e COMMERCIAL
FILENAME: BIS1803-EXB r
B1SCU1TVILLE1SITE DESIGN
./
SCALE' / 1"= 50" 1608 NC 24-87 .2 CAEEDMOGB BO 1911) 84&6121, M 0I918'16P91
RMEIGH. NORM CAROIl1 MU RMW.LSITEDEJIGN COM
DATE. 8/23/2018 CAMERON, NORTH CAROLINA
Biscuitville — HWY 24/87 & Percy Blvd.
Cameron, NC
BIS -1803
High Density Commercial Subdivisions
Deed Restrictions & Protective Convenances
In accordance with Title 15 NCAC 2H.1000 and S. L. 2006-246, the Management Regulations, deed
restrictions and protective covenants are required for High Density Commercial Subdivisions where
lots will be subdivided and sold and runoff will be treated in an engineered stormwater control facility.
Deed restrictions and protective covenants are necessary to ensure that the development maintains a
built -upon area consistent with the design criteria used to size the stormwater control facility.
[,—Tommy Bradford acknowledge, affirm and agree by my
signature below, that I will cause the following deed restrictions and covenants to be recorded prior to
the sale of any lot within the project known as Northgate Highway 87-24 (1400 Block Cameron
Rd.
1. The following covenants are intended to ensure ongoing compliance with State Stormwater
Management Permit Number _SW6111206 , as issued by the Division of
Water Quality under the Stormwater Management Regulations.
2. The State of North Carolina is made a beneficiary of these covenants to the extent necessary to
maintain compliance with the stormwater management permit.
3. These covenants are to run with the land and be binding on all persons and parties claiming
under them.
4. The covenants pertaining to stormwater may not be altered or rescinded without the express
written consent of the State of North Carolina, Division of Water Quality.
5. Alteration of the drainage as shown on the approved plan may not take place without the
concurrence of the Division of Water Quality.
6. The maximum built -upon area per lot, in square feet, is as listed below:
Lot # 1 BUA 43,142 sq ft, Lot # 2 BUA 38,950 Lot # 3 BUA 48,120sq ft, Lot #4 BUA 94, 545sq
ft, Lot# 5A 31,189 sq ft, Lot 5B BUA 33106 sq ft, Lot 5C BUA 32,234sq ft,
Lot 6 29, 853sq ft.
This allotted amount includes any built -upon area constructed within the lot property boundaries,
and that portion of the right-of-way between the front lot line and the edge of the pavement. Built
upon area includes, but is not limited to, structures, asphalt, concrete, gravel, brick, stone, slate,
coquina and parking areas, but does not include raised, open wood decking, or the water
surface of swimming pools.
7. All runoff from the built -upon areas on the lot must drain into the permitted system. This may be
accomplished through a variety of means including roof drain gutters which drain to the street,
grading the lot to drain toward the street, or grading perimeter swales to collect the lot runoff
and directing them into a component of the stormwater collection system. Lots that will naturally
drain into the system are not required to provide these additional measures.
8. The owner of each lot, whose ownership is not retained by the permittee, is required to submit a
separate stormwater permit application to the Division of Water Quality and receive a permit
prior to construction.
9. The project and each lot will maintain a 30** foot wide vegetated buffer between all impervious
areas and surface waters.
**50 foot for projects located in the 20 coastal counties.
Form DRPC-1 Rev.2 05Nov2009 Page 1 of 2
z�%3
1, J1'> , a Notary Public in the
State of M 0 r Vh CO 6h County of
do hereby certify that lornmfpersonally appeared
before me this the ay of 20��, and acknowledge
the cution of the foregoing instrument. Witness my hand and official seal,
SEAL
Sign ture --� `�GREEN'it�,..
M ommission expires P y
Q tiPR Y
U
O f --
r 2 �ev Oar
"�R11
Form DRPC-1 Rev.2 .05Nov2009 Page 2 of
Biscuiriille — HWY 24/87 & Percy Blvd.
Cameron, NC
BIS -1803
Permit No.
(to be provided by DEMLR)
State of North Carolina
Department of Environment and Natural Resources
Division of Energy, Mineral and Land Resources
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
OFF-SITE SYSTEM SUPPLEMENT
FOR DEVELOPMENT DRAINING TO PERMrrrED OFF-SITE TREATMENT SYSTEMS
This forth may be photocopied for use as an original
DEMLR Stormwater Management Plan Review:
A complete stormwater management plan submittal includes a stormwater management permit application, an
off-site system supplement for each off-site stormwater treatment system, appropriate supplement forms for any
on-site stormwater treatment systems, and plans and specifications showing all stormwater conveyances and
drainage details for the project.
L PROJECT INFORMATION
Project Name : BiscuitviIle
Contact Person: Wade J Pudwill Phone Number: f 9191848-6121
Is all drainage from the project directed to the off-site system? (check one): ❑ Yes ® No
II. OFF-SITE SYSTEM INFORMATION (please complete the following information for the off-site system
that will treat runoff from your project):
Permit No. SW6111206
Project Name:Northgate Highway 87-24
Type of System (wet pond, infiltration basin, etc.):Infiltration basin
Lot No. (if part of a subdivision):Lot 5B
How much built upon area draining to the permitted treatment system has been allocated to this
project?33,106sf/0.76 acres
III. REQUIRED ITEMS CHECKLIST
Prior to issuing an off-site permit, verification of the following information must be provided. Initial in the
space provided to indicate that the following requirements have been met and supporting documentation is
attached. If the applicant has designated an agent in the Stormwater Management Permit Application Form, the
agent may initial below. If a requirement has not been met, attach justification.
Foran SW401-Off-Site System-Rev.l Page 1 of 2
Applicants Initials
a. Deed restrictions limiting the built -upon area on the site have been recorded.
b. Engineers certification for the existing off-site system has been submitted to DEMLR.
c. There are no outstanding Notices of Violation for the off-site system.
d. Off-site system is in compliance with the issued permit.
IV. STO ATER COLLECTION SYSTEM MAINTENANCE REQUIREMENTS
Mowing will be accomplished as needed according to the season. Grass height will not exceed six inches at
any time..
2. Accumulated sediment and trash will be removed from the collection system as necessary. Swales and
ditches will be reseeded or sodded following sediment removal.
3. Eroded areas of swales and ditches will be repaired and reseeded. Swales and ditches will be revegetated as
needed based on monthly inspections.
4. The collection system, including catch basins, curb cuts, velocity reduction devices, and piping, will be
inspected monthly or after every significant runoff producing rainfall event. Trash and debris will be
cleared away from grates, curb cuts, velocity reduction devices, and piping.
5. The collection system may not be altered in any way without prior approval from NCDENR Division of
Energy, Mineral and Land Resources.
I acknowledge and agree by my signature below that I am responsible for maintaining the stormwater collection
system in accordance with the five maintenance procedures listed above. I agree to notify DEMLR of any
problems with the system or prior to any changes to the system or responsible party.
Print Name and Title: Maurice N. Jennirtes Jr. - President
Address: -1414 YancMn ille Street Suite 300 Greensboro NC 27405
Phone:919-740-7401 Date:8/23/2018
Note: The legally responsible party should not be a homeowners association unless more than 50% of the lots have been sold and a
resident of the subdivision has been named the president.
' 1t-'r)&Q, SOisc)i() a Notary Public for the State of i `/ e County of
1,
Cg5��2i do hereby certify that MA(Ar;ee �i �2t1(li t1�S �r personally appeared before me this _
day of urHu and acknowledge the due execution of the forgoing document including the stormwater
collection system maintenance requirements.
enGO O Johnson
Gasw la t County
M CommN CSires212412023
SEAL
Witness my hand and official seal,
Notary Public
My commission expires
FormSW-106 Rev 8.07 Page 2 of 2
Fee Paid
came Mum L1 Coastal SW -1995 ❑ Coastal SW --21-08-- 2008 ❑ Ph II - Post Construction
all that apply) ❑ Non -Coastal SW- HQW/ORW Waters❑Universal Stormwater Management Plan
❑ Other WO Morn+ Pla..•
State of North Carolina
Department of Environment and Natural Resources
Division of Energy; Mineral and Land Resources
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
This form may be photocopied for use as an original
L GENERAL INFORMATION
1. Project Name (subdivision, facility, or establishment name - should be consistent with project name on plans,
specifications, letters, operation and maintenance agreements, etc.):
2. Location of Project (street address):
1608 NC 24-87
City:Cameron NC County:Hamett Zip:28326
3. Directions to project (from nearest major intersection):
Travel east on HWY 24. At the intersection of HWY 24 and Uwy 87 take a ftht at off -ram and head
southesast towards Spring Lake. The site is located ARMOximatelv 1.5 miles on the right.
4. Latitude:35° 15' 21.2076" N Longitude:79° 2" 10.5756" W of the Wolin entrance to the project.
IL PERMIT INFORMATION:
1. a. Specify whether project is (check one): ®New []Modification ❑ Renewal w/ Modificationt
tRenewals with mod cations also requires SWU-102 - Renewal Application Form
b. If this application is being submitted as the result of a modification to an existing permit, list the existing
permit number_ , its issue date (if known) and the status of construction:
* *oneNot Started
[]Partially Completed*
❑ Completed proaide a designer's certification
2. Specify the type of project (check one):
[]Low Density []High Density ®Drains to an Offsite stormwater System []Other
3. If this application is being submitted as the result of a previously returned application or a letter from
DEMLR requesting a state stormwater management permit application, list the stormwater project number,
if assigned, and the previous name of the project, if different than currently
proposed,
4. a. Additional Project Requirements (check applicable blanks; information on required state permits can be
obtained by contacting the Customer Service Center at 1-877-623-6748):
[]CAMA Major []Sedimentation/Erosion Control: 0.95 ac of Disturbed Area
[]NPDES Industrial Stormwater []404/401 Permit: Proposed Impacts
b. If any of these permits have already been acquired please provide the Project Name, Project/Permit Number,
issue date and the type of each permit:
5. Is the project located within 5 miles of a public airport? []No ®Yes
If yes, see S.L. 2012-200, Part VI.' htW://portal ncdenr org/web gr/rules and regulations
Fonn SWU-101 Version Oct. 31, 2013 Page I of 6
III. CONTACT INFORMATION
1. a. Print Applicant / Signing Official's name and titleall the developer,property
designated government of iciaL individual, etc. who owns cth Droiect}: P P rtY ower, lessee,
Applicant/Organiaation:Biscuitville Inc
Signing Official & Title:Maurice N. iennin¢s Ir.- President
b. Contact information for person listed in item 1a above:
Street Address 1414 Ysncevvfla Street, Suite 300
City --Greensboro State:NC Zip:27405
Mailing Address (tf applicable):
Cit'' State: ,Zip:
Phone: (919 ) 740-7401 Fax: j_--. )
c. Please check the appropriate box. The applicant listed above is:
® The property owner (Skip to Contact Information, item 3a)
❑ Lessee* (Attach a copy of the lease agreement and complete Contact Information, item 2a and 2b below)
❑ Purchaser* (Attach a copy of the pending sales agreement and
2b below) complete Contact Information item 2a and
❑ Developer* (Complete Contact Information, item 2a and 2b below.)
2. a. Print Property Owner's name and title below, if you are the lessee, purchaser or developer. (This is the
person who owns the property that the project is located on).
Property Owner/OrganizationBisccuitville. [nc.
Signing Official & Title:Maurice N. Termines rr - President
b. Contact information for person listed in item 2a above:
Street Address:14M Yancevville Street, Suite 300
City:Greensboro StateNC Zip:27405
Mailing Address (if applicable):
City: State: Zip:
Phone: ( ) Fax: ( 1
3. a. (Optional) Print the name and title of another contact such as the project's construction supervisor or other
person who can answer questions about the project:
Other Contact Person/Organization
Signing Official & Title:
b. Contact information for person listed in item 3a above:
Mailing Address:
`''Ty: State:
Zip:
Phone: ( } Fax: ( )
Email•
4. Local jurisdiction for building permits: Harnett_ County Building Inspections
Point of Contact _Donna Tohmon Phone #: (910 ) 893-7525
Form SWU-101 Version Oct. 31, 2013 Page 2 of 7
M. PROJECTINFORMATION
1. In the space provided below, briefl�r summarize how the stormwater runoff will be treated.
2. a, If claiming vested rights, identify the
❑Approval of a Site Spsupporting documents provided and the date they were approved:
ecific Development PIan or PUD
❑ Valid Building permit Approval Date:
Other. Issued Date: �^
Date:
b. If claiming vested rights, identify the regulation(s) the project ---------
0 Coastal SW -1995 [] Ph II _ Post Construction
3' Stormwater runoff from this project drains to the Cane Fear
4. Total Property Area. 1.13 River basin.
----------a�'� 5. Total Coastal Wetlands Area
N -acres
Area:
6. Total Surface Water Area: qLA
7. Total Property Area (4) _Total Coastal Wetlands Area (5) - Total Surface Water Area (6) = Total Project acres
Area*:1.13 acres
Total project area sha11 be calculated to exclude the followingg; the normal yool of ounded structures, the area
calllbetween the banks of streams and rivers, the area below the Normal Hi h Water (� line or Mean High Water
overall ppence t bu7fluo�irl W l- the NHW (orMHt� line. The resultant prgect area is used to
be included in the total prgect area. ( "Non -coastal wetlands landward of the NHW (or MHM Byre may
8. Project percent of impervious area: (Total Impervious Area / Total Project Area) X 100 = 60.3 7 %
9. How many drainage areas does the project have?8 (For high density, count 1 for each proposed engineered
stormwater BMP, For low density and other projects, use I for the whole property area)
10. Complete the following information for each drainage area identified in Project Information item 9. If there
are more than four drainage areas in the project, attach an additional sheet with the information for each area
provided in the same format as below.
Form SWU-101 Version Oct. 31, 2013 Page 3 of 7
_
Receiving Stream Name
---
Jumping Run– i.m e rhea
On-site Buildings/Lots (sf)
Creek
Stream Class *
C
Stream Index Number *
18_23-29-3
Total Drainage Area (sf)
571;.743
I (st) 530,561
Area`"` (sf) 28,030
Im ervious' Surface Area
Draina a Area _ Draina a Area—Drama Area Draina a Area
On-site Buildings/Lots (sf)
2,982 — —
On-site Streets (sf)
0
On-site Parking (at)
24,216
On-site Sidewalks (sf)
832
Other on-site (si)
0
Future (sf)
0
Off-site (sf)
0
Existing BUA*** (sf)
0
Total (sf):
29,948
Stream Class and Index i,o a„*,M,..---a _a. ,_.._.
-- «� rLrcp✓ivmtai neaenr orgl7aeb/wg[ps/csulclassi cations
Imderaious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas,
Si
ewalks, gravel areas etc.
***Report only thaf amount of existing BUA that will remain after development. Do not report any existing BUA that
is to be removed and which will be replaced by new BUA.
11. How was the off-site impervious area listed above determined? Provide documentation.
Projects in Union County: Contact DEMLR Central Office staff to check if the project is located within a Threatened &
Endangered Species watershed that may be subject to more stringent stormwater requirements as per 15A NCAC 02B. 0600.
V. SUPPLEMENT AND O&M FORMS
The applicable state stormwater management permit supplement and operation and maintenance (O&M) forms
must be submitted for each BMP specified for this project. The latest versions of the forms can be downloaded
from h!W://portal.ncdenr.org/web/`wq/ws/sulbmp-manual.
VI. SUBMITTAL REQUIREMENTS
Only complete application packages will be accepted and reviewed by the Division of Energy, Mineral and
Land Resources (DEMLR). A complete package includes all of the items listed below. A detailed application
instruction sheet and BMP checklists are available from
httD:/ /r)ortal.ncdenr.nra/web/wg/ws/su/statesw/forms docs. The complete application package should be
submitted to the appropriate DEMLR Office. (The appropriate office may be found by locating project on the
interactive online map at h=:/ /portal.ncdenr org/web/wa /ws/su/mks.)
Please indicate that the following required information have been Provided by initialin in the space provided
for each item. All original documents MUST be signed and initiated in blue ink. Download the latest versions
for each submitted application package from htto://portal.ncdenr org/web/wq/ws/su/statesw/forms docs.
1. Original and one copy of the Stormwater Management Permit Application Form. AIV -
Initials
2. Original and one copy of the signed and notarized Deed Restrictions & Protective Covenants .411A–
Form, (if required as per Part VII below)
3. Original of the applicable Supplement Form(s) (sealed, signed and dated) and O&M
agreement(s) for each BMP.
4. Permit application processing fee of $505 payable to NCDENR. (For an Express review, refer to _.
http•/ /www envheIR org/pages onestopexpress html for information on the Express program
Form SWU-101 Version Oct. 31, 2013 Page 4 of 7
and the associated fees. Contact the appropriate regional office Express Permit Coordinator for
additional information and to schedule the required application meeting.)
5. A detailed narrative (one to two pages) describing the storntwater treatment/managementfor'
the project This is required in addition to the brief summary provided in the Project
Information, item 1.
6. A USGS map identifying the site location. If the receiving stream is reported as class SA or the Ale --
receiving stream drains to class SA waters within % mile of the site boundary, include the Vz
utile radius on the map.
7. Sealed, signed and dated calculations (one copy).—
& Two sets of plans folded to 8.5" x 14" (sealed, Signed, & dated), including:
a. Development/project name.
b. Engineer and firm,
c. Location map with named streets and NCSR numbers.
d. Legend.
e. North arrow,
f. Scale.
g. Revision number and dates.
h. Identify all surface waters on the plans by delineating the normal pool elevation of
impounded structures, the banks of streams and rivers, the MHW or NHW line of tidal
waters, and any coastal wetlands landward of the MHW or NHW lines.
• Delineate the vegetated buffer landward from the normal pool elevation of impounded
structures, the bards of streams or rivers, and the MHW (or NHW) of tidal waters.
i. Dimensioned property/project boundary with bearings & distances.
j. Site Layout with all BUA identified and dimensioned.
k. Existing contours, proposed contours, spot elevations, finished floor elevations.
L Details of roads, drainage features, collection systems, and stormwater control measures.
in. Wetlands delineated, or a note on the plans that none exist (Must be delineated by a
qualified person. Provide documentation of qualifications and identify the person who
made the determination on the plans.
n. Existing drainage (including off-site), drainage easements, pipe sizes, runoff calculations.
o. Drainage areas delineated (included in the main set of plans, not as a separate document).
p. Vegetated buffers (where required).
9. Copy of any applicable soils report with the associated SHWT elevations (Please identify
elevations in addition to depths) as well as a map of the boring locations with the existing
elevations and boring logs. Include an 8.5"x11" copy of the NRCS County Soils map with the
project area clearly delineated. For projects with infiltration BMPs, the report should also
include the soil type, expected infiltration rate, and the method of determining the infiltration rate.
(Infiltration Devices submitted to WiRO: Schedule a site visit for DEMLR to verljy the SHINT prior
to sabmitid, (910) 796-7378.)
10. A copy of the most current property deed. Deed book: 2927 Page No: 406
11. For corporations and limited liability corporations (LLC): Provide documentation from the NC
Secretary of State or other official documentation, which supports the titles and positions held
by the persons listed in Contact Information, item la, 2a, and/or 3a per 15A NCAC 2H.1003(e).
The corporation or LLC must be listed as an active corporation in good standing with the NC
Secretary of State, otherwise the application will be returned.
hm://www.sgaet—ary.state.nc.us/gprj?orations/CSearclLmpx
Form SWU-101 Version Oct. 31, 2013 Page 5 of 7
VII. DEED RESTRICTIONS AND PROTECTIVE COVENANTS
For all subdivisions, outparcels, and future development the appropriate property restrictions and protective
covenants are required to be recorded prior to the sale of any lot. If lot sizes vary significantly or the proposed
BUA allocations vary, a table listing each lot number, lot size, and the allowable built -upon area must be provided
as an attachment to the completed and notarized deed restriction form. The appropriate deed restrictions and
protective covenants forms can be downloaded from htW://portal.ncdenr org/web/Ir/state-stormwater
forms docs. Download the latest versions for each submittal
In the instances where the applicant is different than the property owner, it is the responsibility of the property
owner to sign the deed restrictions and protective covenants form while the applicant is responsible for ensuring
that the deed restrictions are recorded,
By the notarized signature(s) below, the permit holder(s) certify that the recorded property restrictions and
protective covenants for this project, if required, shall include all the items required in the permit and listed
on the forms available on the website, that the covenants will be binding on all parties and persons claiming
under them, that they will run with the land, that the required covenants cannot be changed or deleted
without concurrence from the NC DEMLR, and that they will be recorded prior to the sale of any lot.
VIII. CONSULTANT INFORMATION AND AUTHORIZATION
Applicant: Complete this section if you wish to designate authority to another individual and/or firm (such as a
consulting engineer and/or firm) so that they may provide information on your behalf for this project (such as
addressing requests for additional information).
Consulting Engineer: Wade I Pudwill
Consulting Firm. Commercial Site Design
Mailing Address: 8312 Creedmoor
City: Raleigh
Phone: (919 ) 848-6121
Email:l?udwffl@csitedesign.com
State:NC Zip:27613
Fax: ( 1
IX PROPERTY OWNER AUTHORIZATION (if Contact Information, item 2 has been filled out complete this
section)
I, (print or type name of person listed in Contact Information, item 2a) Maurice N. Jennings fr, -President, certify that I
own the property identified in this permit application, and thus give permission to (print or type name of person
listed in Contact Information, item Ia) Biseuitville with (print or type name of organization listed in
Contact Information, item 1a) Biscuitville to develop the project as currently proposed. A copy of
the lease agreement or pending property sales contract has been provided with the submittal, which indicates the
party responsible for the operation and maintenance of the stormwater system.
Form SWU-101 Version Oct. 31, 2013 Page 6 of 7
As the legal property owner I acknowledge, understand, and agree by my signature below, that if my designated
agent (entity listed in Contact Information item 1) dissolves their company and/or cancels or defaults on thein
lease agreement or pending sale, responsibility for compliance with the DEMLR Stormwater permit reverts back
m me, the property owner. As the property owner, it is my responsibility to notify DEMLR immediately and
submit a compk ted Name/Ownership Change Form within 34 days; otherwise I will be operating a stormwater
treaiutent facility without a valid permit. I understand that the operation of a stormwater treatment facility
without a valid permit is a violation of NC General Statue 143 215.1 end may result in appropriate enforcement
action including the assessment of civil penalties of up to $25040 per day, pursuant to NCGS
143-215.6.
brgnature: -0---..-- � N ,(((���
_ Dater 30
I, )ep �p��5n(\ aNotary Pub for the State of NCSt
County of
do hereby certify that 8eLt n C t^. N (1 n I O' Z5 "S (-
before me this3—L) y �+ pmSO�Y appeared
da of L-' kbA' � and acknowledge the due execution of the a Ife ti f
a stormwater permit Witness my hand and
X, APPLICANT'S CERTIFICATION
SEAL
My commission expires �? ' o14i - aC) a'�3
I, (print or We name ofperson listed in Contact Information, item 1a) Maurice N. Jennings Ir. -President
certify that the information included on this permit application form is, to the best of my knowledge, correct and
that the project will be constructed in conformance with the approved plans, that the required deed restrictions
and protective covenants will be recorded, and that the proposed project complies with the requirements of the
applicable stormwater rules under 15A NCAC 2H,1000 and any other applicable state stormwater requirements.
Signature: —'�---"
Date
1'p tZtc E' S ��� S� a Notary Public the State of _ 1 y
County of
C CleZ:2LIt e i do hereby certify that Maur , Ce. N � nt
'SS- appeared
before me this -So day of A L'
.''{�� ��E�� and acknowledge the due execution of the application for
a stormwater permit. Witness my hand and official seal, , wYS�
SEAL
My commission expires of - ` �3
Form SWU-101 Version Oct, 31, 2013 Page 7 of 7
7
Biscuitville — HW 24/87 & Percy Blvd.
Cameron, NC
BIS -1803
Mr. Bob Skinner
Biscuitville Development
1414 Yanceyville Street
Greensboro, North Carolina 27405
Dear Mr. Skinner:
July 23, 2018
Letter of Infiltration and SHWT Testing
Biscuitville
NC 24-87
Spout Springs, North Carolina
Geo -Hydro Project Number 180348.20
Geo -Hydro Engineers, Inc. has completed the requested infiltration and SHWT testing for the proposed
development on NC 24-87, to the west of the Advance Auto Parts in Cameron, NC. The infiltration and
SHWT testing scope of services is outlined in our amendment to our scope of service for proposal number
21689.2 dated April 9, 2018. Geo -Hydro previously completed a geotechnical engineering evaluation at
the site, documented in our report number 180348.20 dated May 9, 2018.
Infiltration rate testing was performed in general accordance with ASTM D3385 "Standard Test Method
for Infiltration Rate of Soils in Field Using Double -Ring Infiltrometer". One test was performed in the
vicinity of the proposed parking spaces at the north end of the site, near NC 24-87. The approximate location
of the test is shown in the annotated excerpt from the site plan, below. The test results indicate an infiltration
rate of approximately 0.5 inches/hour.
6905 Downwind Road, Suite K . Greensboro, North Carolina 27409 HYDRO
336.553.0870. Fax 336.553.0872. www.goohydro.com ENGINEERS
Letter of Infiltration Rate and SHWr Tesfing - Biscuitville NC 24-87 • Spout Springs, North Carolina
Project Number 180348.20
To evaluate the depth of the seasonally high water table (SHWT) Geo -Hydro performed one hand auger
boring to a depth of 10 feet beneath the existing ground surface in the vicinity of the proposed parking
spaces on the north side of the site. Soil samples obtained from the hand augur boring were classified using
the Unified Soil Classification System as described in ASTM D2487 (Classification of Soils for
Engineering Purposes). Groundwater was not observed in the hand auger boring at the time of, our field
exploration or after 24 hours. Soils obtained from the hand auger boring did not exhibit signs of elevated
moisture or redoximorphic conditions, indicative of the groundwater fluctuation zone. Based on the results
of our field exploration, it is our opinion that the SHWT at the test location does not extend above a depth
of 10 feet below the existing ground surface.
We appreciate the opportunity to serve as your geotechnical consultant for this project and are prepared to
provide any additional services you may require. If you have any questions concerning this report or any
of our services, please call us.
Sincerely,
GEO-HYDRO ENGINEERS, INC.
NC Registered Engineering Firm C-3649
Pryan'� er, E.I.T.
Staff Professional
hporterQa-hydro.mm
G. Douglas Smith, P.E.
Principal
dsmith@geohydro.mm
BP/DS/180348.20 Biscuitville Spout Springs Infiltrometer and SHWT Letter 7-23-I8
July 23, 2018 12
ra H GDRO
HYDRO
ENGINEERS
Report of Subsurface Exploration and
Geotechnical Engineering Evaluation
Biscuitville
Spout Springs, North Carolina
Prepared for
Biscuitville Development
May 9, 2018
OW 4
Mr. Bob Skinner
Biscuitville Development
1414 Yanceyville Street
Greensboro,.North Carolina 27405
Dear Mr. Skinner:
May 9, 2018
Report of Subsurface Exploration and
Geotechnical Engineering Evaluation
Biscuitville
NC 24-87
Spout Springs, North Carolina
Geo -Hydro Project Number 180348.20
Geo -Hydro Engineers, Inc. has completed the authorized subsurface exploration and geotechnical
engineering evaluation for the above referenced project. The scope of services for this project was outlined
in our proposal number 21689.2 dated April 9, 2018.
PROJECT INFORMATION
The project site is located on the south side ofNC 24-87, just east of the existing Advanced Auto Parts store
in Spout Springs, North Carolina. The subject property was previously graded and is relatively flat with
some scrub vegetation and grass. The aerial image below depicts current site conditions.
A new restaurant building is planned to be located
near the center of the lot with associated parking and
driveway areas around the perimeter and a dumpster
pad located at the southwest corner of the property.
We expect the finished floor elevation for the new
building will be close to the existing grade and
minimal mass grading to be required during
construction. We expect the new building to consist
of structural steel framing supported by shallow
foundations with a concrete slab -on -grade floor
system
Design loads for the new building were not available
at the time of this report; however, we expect that
maximum column loads will not exceed about 35 kips
and wall loads will be less than about 1.5 kips per
lineal foot. If actual loads are determined to be
greater than our assumptions, please allow us to
review our recommendations in this report.
6905 Downwind Road, Suite K . Greensboro, North Carolina 27409
336.553.0870 . Fax 336.553.0872 . www.geohydro.com
M T*JH YDRO
Biscuitville— NC 2487 • Spout Springs, North Carolina
Project Number 180348.20
EXPLORATORY PROCEDURES
The subsurface exploration consisted of 7 machine -drilled soil test borings performed at the approximate
locations shown on Figures 2 and 3 included in the Appendix. The borings were located in the field by
Geo -Hydro by measuring angles and distances from existing site features. In general, the boring locations
should be considered approximate.
Standard penetration testing, as provided for in ASTM D1586, was performed at select intervals in the soil
test borings. Soil samples obtained from the drilling operation were examined and classified in general
accordance with ASTM D2488 (Visual -Manual Procedure for Description of Soils). Soil classifications
include the use of the Unified Soil Classification System described in ASTM D2487 (Classification of Soils
for Engineering Purposes). The soil classifications also include our evaluation of the geologic origin of the
soils. Evaluations of geologic origin are based on our experience and interpretation and may be subject to
some degree of error.
Descriptions of the soils encountered, groundwater conditions, standard penetration resistances, and other
pertinent information are provided in the test boring records and the test pit records included in the
Appendix.
REGIONAL GEOLOGY
The project site is located in the Coastal Plain geologic province of North Carolina. The soils comprising
the Coastal Plain include a complex mixture of unconsolidated to weakly indurated marine sediments
consisting of sands, -silts, clays and associated carbonate deposits that were deposited ..^.s the shoreline
migrated with fluctuations in sea level. In upland areas, soil profiles consist of sands, silts, and clays that
for the most part are unchanged since deposition. Where limestone or other carbonate rock are present, soil
profiles typically consist.of a residuum formed by the solutioning of the parent material. In lowland areas,
surficial soils are typically recent and are characterized by the presence of highly organic deposits
associated with flood plains, marshes and swamps. Soils underlying the project site are part of the
Middendorf Formation of the Coastal, Plain, according to the North Carolina Geologic Survey. These soils
are characterized as "sand, sandstone, and mudstone, gray to pale gray with orange case, mottled, clay bolls
and iron -cemented concretions common, beds laterally discontinuous, cross -bedding common".
SOIL TEST BORING SUMMARY
No measureable surface materials were encountered in the borings. All of the borings were performed at
the soil surface and only a scattering of scrub vegetation was observed across the site. For planning
purposes, we suggest considering a thickness of about 5 inches to account for shallow roots across the site.
From the existing ground surface,. boring B-2 encountered what appeared to be previously placed fol
materials extending to a depth of about 8 feet beneath the ground surface. The fill materials were classified
as sand with silt and traces of colloidal organic material. Standard penetration resistances in the fill ranged
from 5 to 8 blows per foot.
From the existing ground surface or beneath the fill materials, all of the borings encountered native soils
typical of the Coastal Plain. The native soils were generally classified as well graded sand with silt or clay.
Standard penetration resistances in the native soils ranged from 5 to 10 blows per foot.
HYDRO
May 9,20182 ENGINEERS
Biscuitville — NC 2487 • Spout Springs, North Carolina
Project Number 180348.20
At the time of drilling, groundwater was not encountered in any of the borings. For safety reasons, all the
borings were backfilled with soil cuttings after the groundwater check. It should be noted that groundwater
levels will fluctuate depending on yearly and seasonal rainfall variations and other factors, and may rise in
the future.
For more detailed descriptions of subsurface conditions, please refer to the test boring records included in
the Appendix.
EVALUATIONS AND RECOMMENDATIONS
The following evaluations and recommendations are based on the information available on the proposed
construction, the data obtained from the test borings, and our experience with soils and subsurface
conditions similar to those encountered at this site. Because the test borings represent a statistically small
sampling of subsurface conditions, it is possible that conditions may be encountered during construction
that are substantially different from those indicated by the test borings. In these instances, adjustments to
the design and construction may be necessary.
Geotechnical Considerations
The following geotechnical characteristics of the site should be considered for planning and design:
One of the seven borings encountered previously placed fill materials extending to a depth of about 8
feet. The composition of the fill and standard penetration resistances recorded. -in the fill indicate
relatively poor compactive effort at the time of fill placement. Previously placed fill materials can be
highly variable and poor quality fill material will likely be encountered. If encountered, poor quality
previously placed fill material should be remediated in accordance with the Site Preparation section of
this report.
• In general, fill materials and native soils within the depths explored should be readily removable using
conventional soil excavation equipment such as loaders and backhoes.
• At the time of drilling, groundwater was not encountered in any of the borings. Groundwater is not
expected to be a concern for site grading or construction. Regardless of groundwater conditions, the
contractor should be prepared to manage surface runoff during rain events and subsurface drainage will
be necessary behind all below -grade structures including foundation walls.
• Contingent upon proper site preparation and thorough evaluation of the foundation excavations, it is
our opinion that the proposed restaurant building can be supported using conventional shallow
foundations and concrete slab -on -grade floors. We recommend an allowable gross bearing pressure of
2,000 psf for design purposes.
• Based on the results of the test borings and following the calculation procedure in the 2012 North
Carolina Building Code, a Site Class E should be used for seismic design. It is possible that a site, class
D may be established for the site by performing a shear wave velocity profile analysis (SW VPA).
HYDRO
May 9, 201813 ENGINEERS
Biscu!Mhe - NC 24-87 • Spout Springs, North Carolina
Project Number 180348.20
The following sections provide recommendations regarding these issues and other geotechnical aspects of
the project.
Existing Fill Materials
Existing fill materials were encountered in I of the 7 test borings. There are several important facts that
should be considered regarding existing fill materials and the limitations of subsurface exploration.
• The quality of existing fill materials can be highly variable, and test borings are often not able to detect
all of the zones or layers of poor quality fill materials.
• Layers of poor quality fill materials that are less than about 2.5 to 5 feet thick may often remain
undetected by soil test borings due to the discrete -interval sampling method used in this exploration.
• The interface between existing fill materials and the original ground surface may include a layer of
organic material that was not properly stripped off during the original grading. Depending on its
relationship to the foundation and floor slab bearing surfaces, an organic layer might adversely affect
support of footings and floor slabs. If such organic layers are encountered during construction, it may
be necessary to "chase out" the organic layer by excavating the layer along with overlying soils.
• The construction budget should include funds for management of poor quality existing fill materials.
• Subsurface exploration is simply not capable of disclosing all conditions that may require remediation.
General Site Preparation
Existing shrubs, grass, topsoil, roots, and other deleterious materials should be removed from the proposed
construction area. All existing utilities should be excavated and removed unless they are to be incorporated
into the new construction. Additionally, site grubbing and stripping should be performed only during dry
weather conditions. Operation of heavy equipment on the site during wet conditions could result in
excessive subgrade degradation. All excavations resulting from demolition of above -grade or below -grade
structures or the rerouting of underground utilities should be backfilled in accordance with the Structural
Fill section of this report.
We recommend that areas to receive structural fill be proofrolled prior to placement of structural fill. Areas
of proposed excavation should be proofrolled after rough finished subgrade is achieved. Proofrolling
should be performed with multiple passes in at least two directions using a fully loaded tandem axle dump
truck weighing at least 18 tons. Proofrolling should be avoided within 10 feet of hardscapes;o remain. If
low consistency soils are encountered that cannot be adequately densified in place, such soils should be
removed and replaced with well compacted fill material placed in accordance with the Structural Fill
section of this report.
For budgeting purposes, we suggest considering that approximately 30 percent of the aggregate building
and pavement areas will require undercutting and replacement extending to a depth of 2 feet. The suggested
stabilization approach is intended only as a tool to estimate a cost associated with general ground
May 9, 2018 14 �E HYDRO
Biscuitville— NC 24.87. Spout Springs, North Carolina
Project Number 180348.20
stabilization. The need for, extent of, location, and optimal method of treating unstable subgrades should
be determined by Geo -Hydro at the time of construction based on actual site conditions. The extent and
cost of ground stabilization may exceed the suggested budgetary estimate.
During site preparation, bury pits or trash pits left over from previous activities at the site may be
encountered Such buried material can be present in isolated areas which are not detected by the soil test
borings. Any buried debris or trash found during the construction operation should be thoroughly excavated
and removed from the site.
Excavation Characteristics
In general, fill materials and native soils within the depths explored should be readily removable using
conventional soil excavation equipment such as loaders and backhoes.
For construction bidding and field verification purposes it is common to provide a verifiable definition of
rock in the project specifications. The following are typical definitions of mass rock and trench rock:
Mass Rock: Material which cannot be excavated with a single -tooth ripper drawn by a crawler tractor
having a minimum draw bar pull rated at 56,000 pounds (Caterpillar D -8K or equivalent), and
occupying an original volume of at least one cubic yard.
• Trench Rock: Material occupying an original volume of at least one-half cubic yard which cannot be
excavated with a hydraulic excavator having a minimum flywheel power rating of 123 kW (165 hp);
such as a Caterpillar 322C L, John Deere 230C LC, or a Komatsu PC220LC-7; equipped with a short
tip radius bucket not wider than 42 inches.
Reuse of Excavated Materials
Based on the results of test borings and our observations, the native soils and fill materials at the site appear
to be suitable for reuse as structural fill: Geo -Hydro should observe the excavation of existing fill materials'
to evaluate their suitability for reuse. Soft, unstable fill soils free of deleterious materials may be reusable
after routine moisture adjustment. Highly organic soils and debris -laden soils will not be suitable for reuse.
Routine adjustment of moisture content will be necessary to allow proper placement and compaction.
It is important to establish as part of the construction contract whether soils having elevated moisture
content will be considered suitable for reuse. We often find this issue to be a point of contention and a
source of delays and change orders. From a technical standpoint, soils with moisture contents wet of
optimum as determined by the standard Proctor test (ASTM D698) can be reused provided that the moisture
is properly adjusted to within the workable range. From a practical standpoint, wet soils can be very
difficult to dry in small or congested sites and such difficulties should be considered during planning and
budgeting. A clear understanding by the general contractor and grading subcontractor regarding the reuse
of excavated soils will be important to avoid delays and unexpected cost overruns.
Structural Fill
Materials selected for use as'structural fill should be free of organic debris, waste construction debris, and
other deleterious materials. The material should not contain rocks having a diameter over 4 inches. It is
D
May 9,291815 ENGINEERS �O
Biscuitville- NC 2487 • Spout Springs, North Carolina
Project Number 180348.20
our opinion that the following soils represented by their USCS group symbols will typically be suitable for
use as structural fill and are usually found in abundance in the Coastal Plain province: (SM), (ML), and
(CL), (SW), (SP), (SC), (SW -SM) and (SW -SC). The following soil types are considered unsuitable: (MH),
(CH), (OL), (OH), and (Pt).
Laboratory Proctor compaction tests and classification tests should be performed on representative samples
obtained from the proposed borrow material to provide data necessary to determine acceptability and for
quality control. The moisture content of suitable borrow soils should generally be no more than 3
percentage points below or above optimum at the time of compaction. Tighter moisture limits may be
necessary with certain soils.
Suitable fill material should be placed in thin lifts. Lift thickness depends on the type of compaction
equipment, but a maximum loose -lift thickness of 8 inches is generally recommended. The soil should be
compacted by a self-propelled sheepsfoot or smooth drum steel roller. Clayey or silty soils can be
compacted more efficiently with a sheepsfoot roller. Relatively clean sands (low percentage of fines),
similar to those encountered in the soil test borings at the site, respond better to smooth steel drum, vibratory
rollers. Within small excavations such as in utility trenches, around manholes, above foundations, or behind
retaining walls, we recommend the use of "wacker packers" or "Rammax" compactors to achieve the
specified compaction. Loose lift thicknesses of 4 to 6 inches are recommended in small area fills.
We recommend that structural fill be compacted to at least 95 percent of the standard Proctor maximum
dry density (ASTM D698). The upper 12 inches of floor slab subgrade soils should be compacted to at
least 98 percent of the standard Proctor maximum dry density. Additionally, the maximum dry density of
structural fill should be no less than 90 pcf. Following North Carolina DOT guidelines, the upper 8 inches
of pavement subgrade soils should be compacted to at least 100 percent of the maximum dry density as
determined by AASHTO T99. Geo -Hydro should perform density tests during fill placement.
Earth Slopes
Temporary construction slopes should be designed in strict compliance with current OSHA regulations.
The soil test borings indicate that the soils at the site are Type C as defined in 29 CFR 1926 Subpart P. This
dictates that temporary construction slopes be no steeper than 1.5H:1 V for excavation depths of 20 feet or
less. Excavations should be closely observed daily by the contractor's "competent person" for signs of
mass movement: tension cracks near the crest, bulging at the toe of the slope, etc. The responsibility for
excavation safety and stability of construction slopes should lie solely with the contractor.
We recommend that extreme caution be observed in trench excavations. Several cases of loss of life due
to trench collapses in North Carolina point out the lack of attention given to excavation safety on some
projects. We recommend that applicable local and federal regulations regarding temporary slopes, and
shoring and bracing of trench excavations be closely followed.
Formal analysis of slope stability was beyond the scope of work for this project. Based on our experience,
permanent cut or fill slopes should be no steeper than 2H:1 V to maintain long term stability and to provide
ease of maintenance. The crest or toe of cut or fill slopes should be no closer than 10 feet to any foundation.
The crest or toe should be no closer than 5 feet to the edge of any pavements. Erosion protection of slopes
May 9, 2018 16 [c]J*J H YD RO
Biscuitville- NC 2487 • Spout Spdngs, North Carolina
Project Number 180348.20
during construction and during establishment of vegetation should be considered an essential part of
construction.
Earth Pressure
Three earth pressure conditions are generally considered for retaining wall design: "at rest", "active", and
"passive" stress conditions. Retaining walls which are rigidly restrained at the top and will be essentially
unable to rotate under the action of earth pressure (such loading dock walls) should be designed for "at rest"
conditions. Retaining walls which can move outward at the top as much as 0.5 percent of the wall height
(such as free-standing walls) should be designed for "active" conditions. For the evaluation of the resistance
of soil to lateral loads the "passive" earth pressure must be calculated. It should be noted that full
development of passive pressure requires deflections toward the soil mass on the order of 1.0 percent to 4.0
percent of total wall height.
Earth pressure may be evaluated using the following equation:
ph = K (DZ + qs) + Ww(Z-d)
where: ph = horizontal earth pressure at any depth below the ground surface (Z).
Ww = unit weight of water
Z = depth to any point below the ground surface
d = depth to groundwater surface
Dw = wet unit weight of the soil backfill (depending on borrow sources). The wet unit weight
of most residual soils may be expected to range from approximately 115 to 125 pcf.
Below the groundwater level, Dw must be the buoyant weight.
qs = uniform surcharge load (add equivalent uniform surcharge to account for construction
equipment loads)
K = earth pressure coefficient as follows:
Earth Pressure Condition
Coefficient
At Rest (K")
0.50
Active (Ka)
0.33
Passive (Kp)
3.00
The groundwater term, Ww(Z-d), should be used if no drainage system is incorporated behind retaining
walls. If a drainage system is included which will not allow the development of any water pressure behind
the wall, then the groundwater term may be omitted. The development of excessive water pressure is a
common cause of retaining wall failures. Drainage systems should be carefully designed to ensure that
long term permanent drainage is accomplished.
The above design recommendations are based on the following assumptions:
Horizontal backfill
• 95 percent standard Proctor compactive effort on backfill (ASTM D698)
• No safety factor is included
For convenience, equivalent fluid densities are frequently used for the calculation of lateral earth pressures.
For "at rest" stress conditions, an equivalent fluid density of 63 pcf may be used. For the "active" state of
reMo HYDRO
May 9, 201817 ENGINEERS
Biscuitville- NC 24-87 • Spout Springs, North Carolina
Project Number 180348.20
stress an equivalent fluid density of 42 pcf may be used. These equivalent fluid densities are based on the
assumptions that drainage behind the retaining wall will allow no development of hydrostatic pressure; that
native sandy silts or silty sands will be used as .backfill; that the backfill soils will be compacted to 95
percent of standard Proctor maximum dry density; that backfill will be horizontal; and that no surcharge
loads will be applied
For analysis of sliding resistance of the base of a cast -in-place concrete retaining wall, the coefficient of
friction may be taken as 0.42 for the soils at the project site. This is an ultimate value, and an adequate
factor of safety should be used in design. The force which resists base sliding is calculated by multiplying
the normal force on the base by the coefficient of friction. Full development of the frictional force could
require deflection of the base of roughly 0.1 to 0.3 inches.
Foundation Design
After general site preparation and site grading have been completed in accordance with the
recommendations of this report, it is our opinion that the proposed building can be supported using
conventional shallow foundations. We recommend an allowable gross bearing pressure of 2,000 psf for
foundation design. In addition, we recommend a minimum width of 24 inches for column footings and 18
inches for continuous wall footings to prevent general bearing capacity failure. Footings should bear at a
minimum depth of 18 inches below the prevailing exterior ground surface elevation to avoid potential
problems due to frost heave.
The recommended allowable bearing pressure is based on a maximum column load of 35 kips and a
maximum wall load of 1.5 kips per lineal foot, as well as an estimated maximum total foundation settlement
no greater than approximately 1 inch, with anticipated differential settlement between adjacent columns not
exceeding about '/2 inch. If the architect or structural engineer determine that the maximum anticipated
loads exceed our estimated values, or if it is determined that the estimated total or differential settlement
cannot be accommodated by the proposed structure, please contact us. If the location of the proposed
structure is moved from the proposed location, please contact us.
Foundation bearing surface evaluations should be performed in all footing excavations prior to placement
of reinforcing steel. These evaluations should be performed by Geo -Hydro to confirm that the design
allowable soil bearing pressure is available. Foundation bearing surface evaluations should be performed
using a combination of visual observation, hand angering, and portable dynamic cone penetrometer testing
(ASTM STP -399).
Because of natural variation, it is possible that some of the soils at the project site may have an allowable
bearing pressureless than the recommended design value. Likewise, existing fill materials are highly
variable and may have an allowable bearing pressure less than the recommended design value. Therefore,
foundation bearing surface evaluations will be critical to aid in the identification and remediation of these
situations.
Remedial measures should be based on actual field conditions. However, in most cases we expect the use
of the stone replacement technique to be the primary remedial measure. Stone replacement involves the
removal of soft or loose soils, and replacement with consolidated No. 57 size aggregate meeting North
Carolina Department of Transportation specifications for gradation. Stone replacement is generally
May 9, 2018 18 H DRO
Biscuitvile— NC 2487 • Spout Springs, North Carolina
Project Number 180348.20
performed to depths ranging from a few inches to as much as 2 times the footing width, depending on the
actual conditions. For budgeting purposes, we suggest considering a contingency to treat approximately
30 percent of the foundation excavations using stone replacement extending to a depth of 3 feet below
bearing elevation. The actual quantity of stone replacement will be different and may exceed the suggested
estimate.
Seismic Design
Based on the results of the test borings and following the calculation procedure in the 2012 North Carolina
Building Code, a Site Class E should be used for seismic design. The mapped and design spectral response
accelerations are as follows: Ss=0.276, St=0.097, SDs=0.444, Sm=0.227. It is possible that a site class D
may be established for the site by performing a shear wave velocity profile analysis (SW VPA).
Based on the information obtained from the soil test borings, it is our opinion that the potential for
liquefaction of the residual soils at the site due to earthquake activity is relatively low.
Floor Slab Subarade Preparation
The soil subgrade in the area of concrete slab -on -grade support is often disturbed during foundation
excavation, plumbing installation, and superstructure construction. We recommend that the floor slab
subgrade be evaluated by Geo -Hydro immediately prior to beginning floor slab construction. If low
consistency soils are encountered that cannot be adequately densified in place, such soils should be removed
and replaced with well -compacted fill material placed in accordance with the Structural Fill section of this
report or with well -compacted aggregate base coursc (ABC).
Assuming that the top 12 inches of floor slab subgrade soils are compacted to at least 98 percent of the
standard Proctor maximum dry density, we recommend that a modulus of subgrade reaction of 120 pci be
used for design.
Moisture Control for Concrete Slabs
To prevent the capillary rise of groundwater from adversely affecting the concrete slab -on -grade floor, we
recommend that slab -on -grade floors be underlain by a minimum 4 -inch thickness of open -graded stone.
Use of #57 crushed stone meeting North Carolina DOT specifications for gradation is suggested. The stone
course must be covered by a vapor retarder. We suggest polyethylene sheeting at least 10 mils thick as a
minimum vapor retarder.
Flexible Pavement Design
Based on our experience with similar projects, assuming standard pavement design parameters, and
contingent upon proper pavement subgrade preparation, we recommend the following pavement sections:
Heaw Dutv Traffic Areas
Material
Thickness (inches)
As halfic Concrete SUB Sue ave
1.5
Asphallic Concrete 1198 Su er ave
2.5
Aggregate Base Course ABC
8
Sub rade compacted to at least 100% of AASHTO T99
8
May 9, 2018 19 HYDRO
Biscuitville - NC 24-87. Spout Springs, North Carolina
Project Number 180348.20
A concrete thickness of 6 inches is recommended for the approach and collection zone in front of the
dumpster. Please refer to the Concrete Pavement section of this report for concrete pavement
recommendations.
The top 8 inches of pavement subgrade soils should be compacted to at least 100 percent of the maximum
dry density as determined by AASHTO T99 (ASTM D698). Scarification and moisture adjustment will
likely be required to achieve the recommended subgrade compaction level. Allowances for pavement
subgrade preparation should be considered for budgeting and scheduling.
ABC should be compacted to at least 100 percent of the maximum dry density as determined by AASHTO
T180 (ASTM D1557).
All pavement construction should be performed in general accordance with North Carolina DOT
specifications. Proper subgrade compaction, adherence to North Carolina DOT specifications, and
compliance with project plans and specifications, will be critical to the performance of the constructed
pavement.
Concrete Pavement
A rigid Portland cement concrete pavement may be considered. Although usually more costly, a Portland
cement concrete pavement is typically more durable and requires less maintenance throughout the life cycle
of the facility. Concrete thicknesses of 5 inches in automobile parking areas and 6 inches in driveways and
truck traffic areas are recommended. A concrete thickness of 6 inches is recommended for the approach
and collection zone in front of the dumpster and in loading dock aprons. A 650 -psi flexural strength
concrete mix (approximate compressive strength of 4,500 psi) with 4 to 6 percent air entrainment should
be used. The concrete pavement must be underlain by no less than 5 inches of compacted aggregate base
course (ABC). ABC should be compacted to at least 100 percent of the maximum dry density as determined
by AASHTO TI 80. The top 8 inches of soil subgrade should be compacted to at least 100 percent of the
maximum dry density as determined by AASHTO T99.
The concrete pavement may be designed as a "plain concrete pavement" with no reinforcing steel, or
reinforcing steel maybe used at joints. Construction joints and other design details should be in accordance
with guidelines provided by the Portland Cement Association and the American Concrete Institute.
In general, all pavement construction should be in accordance with North Carolina DOT specifications.
Proper subgrade compaction, adherence to North Carolina DOT specifications, and compliance with project
plans and specifications will be critical to the performance of the constructed pavement.
May 9, 2018 110 �H YDRO
Biscuitville — NC 2487 • Spout Springs, North Carolina
Project Number 180348.20
Pavement Design Limitations
The pavement sections discussed above are based on our experience with similar type facilities. After
traffic information has been developed, we recommend that you allow us to review the traffic data and
revise our recommendations as necessary.
Pavement Materials Testing
To aid in verifying that the pavement system is installed in general accordance with the design
considerations, the following materials testing services are recommended:
• Density testing of subgrade materials.
• Proofrolling of pavement subgrade materials immediately prior to placement of aggregate base course
(ABC). This proofrolling should be performed the same day ABC is installed.
• Proofrolling of the ABC surface immediately prior to paving.
• Density testing of ABC and verification of ABC thickness. In-place density should be verified using
the sand cone method (ASTM D1556).
• Coring of the pavement to verify thickness and density (asphalt pavement only). Three cores should
be sufficient to evaluate the finished pavement.
• Preparation and testing of beams or cylinders for compressive strength testing (Portland cement
concrete only). The total number of test specimens required will depend on the number of concrete
placement events necessary to construct the pavement.
We appreciate the opportunity to serve as your geotechnical consultant for this project, and are prepared to
provide any additional services you may require. If you have any questions concerning this report or any
of our services, please call us.
Sincerely,
GEO-HYDRO ENGINEERS, INC.
NC Registered Engineering Firm C -��...,,,,
2&_nQH c ��,I,"8
EALt
_ C 037M; ;
G. D&agladSmt`th, P.E.
Principal
dsmdh@geohydro.com
GDS/AMP/rao348.2o Bi,cWtviue - spwt spdnge, BwBngton
May 9, 2018111
A. Marty,PenfngY,
Senior deotechnical Engineer
mpaninger@geohydro.com
HYDRO
ENGINEERS
APPENDIX
HYDRO
ENGINEERS
FIGURES
HYDRO
ENGINEERS
�WDRO
ENGINEERS
1
t
i
1
t
i
I
ZOuxM/k
0 0.25 0.5 1 1.5
Approximate Scale, Miles
Biscuitville
Figure 1: Site Location Plan Spout Springs, North Carolina
Geo -Hydro Project Number 180348.00
z
1
S
3
{
1
k
1
3
3
i
{
k
1
1
1
3
S
1
t
i
1
t
i
I
ZOuxM/k
0 0.25 0.5 1 1.5
Approximate Scale, Miles
Biscuitville
Figure 1: Site Location Plan Spout Springs, North Carolina
Geo -Hydro Project Number 180348.00
PCYX2V:. e
lOr.n
IOJOT AL y _.
FX MMIIY•. (�
FXKT!M1C!
LEGEND: $� Soil Test Boring
rc-TMeIHYDRO
ENGINEERS
yc
0 20 40 80 120
Approximate Scale: V=40'
Biscuitville
Figure 2: Boring Location Plan Spout Springs, North Carolina
Geo -Hydro Project Number 180348.00
�0
TEST BORING RECORDS
reMe HYDRO
Symbols and Nomenclature
Symbols
Thin-walled tube (TWT) sample recovered
Thin-walled tube (TWT) sample not recovered
■ Standard penetration resistance (ASTM D1586)
50/2" Number of blows (50) to drive the split -spoon a number of inches (2)
65% Percentage of rock core recovered
RQD Rock quality designation - % of recovered core sample which is 4 or more inches long
GW Groundwater
V Water level at least 24 hours after drilling
V Water level one hour or less after drilling
ALLUV Alluvium
TOP Topsoil
PM Pavement Materials
CONC Concrete
FILL Fill Material
RES Residual Soil
PWR Partially Weathered Rock
SPT Standard Penetration Testing
Penetration Resistance Results
Approximate
Number of Blows, N
Relative Density
Sands 04
very loose
5-10
loose
11-20
firm
21-30
very firm
31-50
dense
Over 50
very dense
Approximate
Number of Blows, N
Consistency
Silts and 0-1
very soft
Clays 24
soft
5-8
firm
9-15
stiff
16-30
very stiff
31-50
hard
Over 50
very hard
Drilling Procedures
Soil sampling and standard penetration testing performed in accordance with ASTM D 1586. The standard penetration resistance is the amber
of blows of a 140-pomdhan mer falling 30 inches to drive a 2 -inch O.D, 1.4inch LD. split -spoon sampler one foot Rock coring is performed
in accordance with ASTM D 2113. Thin-walled tube sampling is performed in accordance with ASTM D 1587.
IMainUeo/MisdSymbols&Nom=claom,
B.1 Test Boring Record HYDRO
ENGINEERS
Project: Biscuitville
Project No: 180348.20
Location: Spout Springs, North Carolina
Date: ' 4128118
Method: HSA -ASTM D1586
GWT at Drillin : NE (Caved at 9 feet)
G.S. Elev:
Driller: Ca itaI (Auto Hammer)
GWT at 24 hrs: WA (Bonn Backfilled)
Logged By: GDS
Standard Penetration Test
W
-
�-
c�
E
Description
N
(Blows/Foot)
rn
o in 90 n3 so
X.
Loose tan and brown fine to medium sand
with silt (SW -SM) (NATIVE)
7
•
5
8
7
•
Loose tan and orange fine to coarse sand
with Gay (SW -SC)
10-
X.
9
16 --*:.Boring
Terminated at 15 feet 10
20 -
Remarks:
B_2 Test Boring Record HYDRO
ENGINEERS
Project: Biscuitville
Project No: 180348.20
Location: Spout Springs, North CArolina
Date: 4128118
Method: HSA- ASTM D1586
GWT at Drilling: NE (Caved at 8 feet)
G.S. Elev:
Driller. Capital (Auto Hammer)
GWT at 24 hrs: NIA Boring Backfilled
Logged By: GDS
a
Standard Penetration Test
w
_
Q LL
€
Description
N
(Blows/Foot)
o ea 1a eo JUM
Loose dark brown fine to coarse sand with
silt (SW -SM) and traces of colloidal organic
materials (FILL)
j
5
5
g
6
�
Loose tan fine to coarse sand with silt
(SW -SM) (NATIVE)
to
7
15
Boring Terminated at 15 feet 10
20
Remarks:
B=3 Test Boring Record HYDRO
ENGINEERS
Project: Siscuitville
Project No: 180348.20
Location: Spout Springs, North Carblina
Date: 4128/18
Method: HSA- ASTM D1586
GWT at Drilling: NE (Caved at 7 feet)
G.S. Elev:
Driller: Capital Auto Hammer)
GWT at 24 hrs: N/A (Boring Backfilled)
Logged By: GDS
Standard Penetration Test
(Blows/Foot)
w i✓
g LL.
€
Description
N
Li
10 W 40 60 60
Loose tan fine to medium sandwith clay
X.
(SW -SC) (NATIVE)
X.
s
•
5
5
7
•
Loose orange fine to coarse sand with silt
(SW -SM)
10
s
X.
15
Boring Terminated at 15 feet 10
20
Remarks:
P-1 Test Boring Record HYDRO
ENGINEERS
Project: Biscuitville
Project No: 180348.20
Location: Spout Springs, North Carolina
Date: 4/28/18
Method: HSA -ASTM D1586
GWT at Drilling: NE (Caved at 2 feet)
G.S. Elev:
Driller: Ca ital Auto Hammer)
GWT at 24 hrs: N/A (Boring Backfilled)
Logged B : GDS
Standard Penetration Test
W E8
-
-
Description
N .
(BlowslFoot)
0 in 20 M
Loose tan fine to medium sand with silt
(SW -SM) and traces of colloidal organic
material (NATIVE)
14
s
s
Boring Terminated at 5 feet 8
ois2010-
15-
20
Remarks:
P.2 Test Boring Record FMq HYDRO
ENGINEERS
Project: Biscuitville
Project No: 180348.20
Location:.Spout Springs, North Carolina
Date: 4128118
Method: HSA- ASTM D1586
GWT at Drillin : NE (Caved at 3 feet)
G.S. Elev:
Driller: Capital (Auto Hammer
GWT at 24 hrs: NIA (Boring Backfilled)
Logged By: GDS
Standard Penetration Test
LU
N
N
(Blows/Foot)
Description
a 10 3a Q 50 60 M 80
Loose tan fine to coarse sand with silt
(SW -SM) (NATIVE)
s
5
Boring Terminated at 5 feet 7
10-
15-
20—
Remarks
P.3 Test Boring Record HYDRO
ENGINEERS
Project: Biscuitville
Project No: 180348.20
Location: Spout Springs, North Carolina'
Date: 4128118
Method: HSA- ASTM D1586
GWT at Drilling: NE (Caved at 3 feet)
G.S. Elev:
Driller: Capital (Auto Hammer)
GWT at 24 hrs: WA (Boring Backfilled)
Logged By: GDS
Standard Penetration Test
w
E
Description
N
(Blom/Foot)
z qn An o 7o e
Loose tan and orange fine to coarse sand
X.
with clay (SW -SC) (NATIVE)
X.-
8
•
5
Boring Terminated at 5 feet 9
10
15
20
Remarks:
P.4 Test Boring Record HYDRO
ENGINEERS
Project: Biscuitville
Project No: 180348.20
Location: Spout Springs, North Carolina
Date: 4/28f18 '
Method: HSA -ASTM D1586
GWT at Drilling: NE (Caved at 3 feet)
G.S. Elev:
Driller: Capital (Auto Hammer)
GWT at 24 hrs: N/A (BoringBackfilled)
Logged By: GDS
£
o
Standard Penetration Test
w
i.
Description
N
(Blows/Foot)
y
o is o w ao
Loose tan and brown fine to coarse sand
with silt (SW -SM) (NATIVE)
X.
s
5
X.
Boring Terminated at 5 feet s
10-
020Remarks:
20—
Remarks:
PHOTO PAGES
rff HYDRO
ENGINEERS
BiscuitviDe . Spout Springs, North Carolina
Project Number 180348.20
• `. „ 41b yNy .yf
Photo 1: View looking north across site.
—
2: View looking south across site
6905 Downwind Road, Suite K • Greensboro, North Carolina 27409 HYDRO
o: 336.553.0870. f: 336.553.0872 • www.geohydro.com ENGINEERS
W
Biscui[ville—HWY 24/87 & Percy Blvd.
Cameron, NC
BIS -1803
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PERMEABLE PAVEMENT CONSTRUCTION SPECIFICATIONS:
1. ENSURE ACCEPTABLE CONDITIONS FOR CONSTRUCTION. DO NOTBEGIN CONSTRUCTION ON
PERMEABLE PAVEMENT UNTIL ACCEPTABLE CONDITIONSARE PRESENT THIS INCLUDES THE
FOLLOWING ITEMS:'
A. PERVIOUS SURFACES ARE GRADED SO THAT THEYDO NOT DISCHARGE TOME PERMEABLE
PAVEMENT, EXCEPT FOR INSTANCES WHEN THIS IS UNAVOIDABLE
S. ALL AREAS OF ME SITEADJACENT TO THE PERMEABLE PAVEMENTAREREQUIRED TO BE STABIUZEDWITH
VEGETATION, MULCH, STRAW, SEED, SOD, FIBER BLANKETS OR OTHER APPROPRIATE COVER IN ORDER TO
PREVENT EROSION AND POSSIBLE CLOGGING OF SEDIMENTS
C. NO CONSTRUCTION TRAFFIC IS ALLOWED TO PASS THROUGH THE PERMEABLE
PAVEMENT AREA DURING INSTALLATION INSTALL BARRIERS OR FENCES AS NEEDED.
D. ALL PERMEABLE PA VEMENT AREAS ARE REQUIRED TO BE PERMANENTLY MARKED ONSITE WITH SIGNAGE.
2. FIRST STEP IN CONSTRUC TON IS TO EXCA VATE THE PA VEMENT AREA SHOWN ON PLANS AND
PREPARE SUBGRADE. PROTECT INFILTRATION RATES USING FOLLOWING THESE STEPS:
A. EXCA VATE IN OR Y SUBGRADE CONDITIONS AND A VOID EXCA VA TING IMMEDIATELYAFTER
STORMS WITHOUT A SUFFICIENT DRYING PERIOD.
B. 00 NOT ALLOW EQUIPMENT TO CROSS THE PAVEMENT AREA AFTER EXCAVATON HAS STARTED.
C. OPERA TE EXCAVATION EQUIPMENT FROM OUTSIDE THE PAVEMENT AREA OR FROM
UNEXCAVATED PORTIONS OF THE AREA USING AN EXCAVATION STAGING PLAN.
D. USE EQUIPMENT WITH TRACKS RA THER THAN TIRES TO MINIMIZE SOIL COMPACTION WHEN
EQUIPMENT ON THE SUBGRADE SURFACE IS UNAVOIDABLE.
E DIG THE FINAL 8 TO 121N. BY USING THE TEETH OF THE EXCAVATOR BUCKET TO LOOSEN
SOIL AND DO NOT COMPACT THE SUBGRADE SOIL SURFACE. FINAL GRADING
OF THE SUBGRADE SHOULD BE DONE WITHOUT MACHINERY IF POSSIBLE.
F MINIMIZE THE TIME BETWEEN EXCAVA TION AND PLACEMENT OF ME AGGREGATE.
3 TEST THE SUBGRADE SOIL INFILTRATION RATE. CONDUCT A DIRECTMEASUREMENT OF THE
SOIL'S INFILTRATION RATE IMMEDIATELYAFTER EXCAVATION AND BEFORE THE AGGREGATE IS
PLACED. INFILTRATION RATE TESTING SHALL BE CONDUCTED RYAN APPROPRIATELY-QUALIFIED
PROFESSIONAL. THE RESULTS OF THE TESTING SHALL BE GIVEN TO THEDESIGNER OFRECORD
FOR REVIEW.
d. PLACE GEOTEXTILES AND GEOMEMBRANE(IF APPLICABLE), IF USING GEOTEXTILES OR
GEOMEMBRANES, THEN FOLLOW THE MANUFACTURER'S RECOMMENDATIONS SO FOR THE
APPROPRIATE O VERLAP BETWEEN ROLLS OF MATERIAL. SECURE GEOTEXTILE OR
GEOMEMBRANE SO THAT IT WILL NOT MOVE OR WRINKLE WHEN PLACING AGGREGATE.
B. PLACE CATCH BASINS, OBSER VATION WELL(S) AND UNDERDRAW SYSTEM. PLACE ME CATCH
BASINS AND OBSERVA TION WELLS ACCORDING TO THE DESIGN PLANSAND VERIFY THAT THE
ELEVATIONS ARE CORRECT. IF AN UPTURNED ELBOW DESIGN IS USED, THEN THE UNDERDRAINS
ARE PLACED FIRST. IN SUCH CASE, VERIFY ME FOLLOWING:
A. ELEVA TIONS OF THE UNDERDRAINS AND UPTURNED ELBOWS ARE CORRECT.
B. DEAD ENDS OF PIPE UNDERDRAINS ARE CLOSED WITH A SUITABLE CAP PLACED OVER ME
END AND HELD FIRMLY IN PLACE
C. PORTIONS OF THE UNDERDRAIN SYSTEM WITHIN ONE FOOT OF ME OUTLET STRUCTURE
ARE SOLID AND NOT PERFORATED.
B. PLACE AND COMPACTAGGREGA TEBASE. INSPECT ALL AGGREGATES TO INSURE THEYARE
CLEAN. FREE OF FINES AND CONFORM TO THE PLANS AND SPECIFICATIONS IF AGGREGATES
DELIVERED TO THE SITE CANNOT BE IMMEDIA TELY PLACED INTO THE EXCAVATION, THEY SHOULD
BE STOCKPILED ON AN IMPERVIOUS SURFACE, GEOTEXTILE, OR ON AN IMPERVIOUS MATERIAL TO
KEEP THE AGGREGA TE FREE OF SEDIMENT IF AGGREGATE BECOMES CONTAMINATED WITH
SEDIMENT, THEN IT SHALL BE REPLACED WITH CLEAN MATERWLS.
A. BEFORE PLACING THE AGGREGATE BASE, REMOVE ANY ACCUMULATION OF SEDIMENTS ON
THE FINISHED SOIL SUBGRADE, USE LIGHT, TRACKED EQUIPMENT. IF THE EXCA VATED
SUBGRADE SURFACE IS SUBJECTED TO RAINFALL BEFORE PLACEMENT OF ME AGGREGATE
BASE, THE RESULTING SURFACE CRUST MUST BE EXCAVATED TO AT LEASTAR ADDITIONAL
21N, DEPTH, RAKED OR SCARIFIED TO BREAK UP THE CRUST FOR SIMS MM AN
IMPERMEABLE LINER OR GEOTEXTILES, REMOVE ANY ACCUMULATED SEDIMENTS AND
CHECK PLACEMENT SLOPES AND ELEVATIONS SHALL BE CHECKED ON ME SOIL SUBGRADE
AND THE FINISHED ELEVATION OF BASE (AFTER COMPACTION) OR BEDDING MATERIALS TO
ASSURE THEY CONFORM TO THE PLANS AND SPECIFICATIONS
B. ALL AGGREGA TE SHALL BE SPREAD (NOT DUMPED) BY A FRONT-END LOADER OR FROM
DUMP TRUCKS DEPOSITING FROM NEAR THE EDGE OF THE EXCAVATED AREA OR RESTING
DIRECTLY ON DEPOSITED AGGREGATE PILES. MOISTEN AND SPREAD THE WASHED STONE
WITHOUT DRIVING ON THE SOIL SUBGRADE, BE CAREFUL NOT TO DAMAGE UNDERDRAINS
AND THEIR FITTINGS, CATCH BASINS, OR OBSERVATION WELLS WRING COMPACTION.
FOLLOW COMPACTION RECOMMENDATIONS BY THE PERMEABLE PAVEMENT
MANUFACTURER OR THAT FROM INDUSTRY GUIDELINES. BE SURE THAT CORNERS, AREAS
AROUND UTILITY STRUCTURES AND OBSERVATION WELLS, AND TRANSITION AREAS TO
OTHER PAVEMENTS ARE ADEQUATELY COMPACTED. DO NOT CRUSH AGGREGA TES DURING
COMPACTION AS THIS GENERATES ADDITIONAL FINES THAT MAY CLOG THE SOIL SUBGRADE.
T. INSTALL CURB RESTRAINTS AND PAVEMENT BARRIERS. EDGE RESTRA/NTSAND BARRIERS
BETWEEN PERMEABLE AND IMPERVIOUS PAVEMENT SHALL BE INSTALLED PER DESIGN. BEFORE
MOVING ON TO NEXT STEP, BE CERTAIN THAT THE DESIGN AND INSTALLATION ARE CONSISTENT.
B INSTALL BEDDING AND PAVEMENT COURSES THE BEDDING AND PAVEMENT COURSE
INSTALLATION PROCEDURES DEPEND ON THE PERMEABLE PAVEMENT SURFACE. RIS IMPORTANT
TO FOLLOW THE SPECIFICATIONS AND MANUFACTURER'S INSTALLATION INSTRUCTIONS.
9 PROTECT THE PAVEMENT THROUGH PROJECT COMPLETION. IF IS PREFERABLE TO HAVE THE
PERMEABLE PAVEMENT INSTALLED AT THE END OF THE SITE CONSTRUCTION TIMELINE IF THAT IS
NOT POSSIBLE, PROTECT THE PERMEABLE PAVEMENT UNTk PROJECT COMPLETION. THIS SHALL
BE DONE BY
A. ROUTE CONSTRUCTION ACCESS THROUGH OTHER PORTIONS OF ME SITE SO THAT NO
CONSTRUCTION TRAFFIC ASSES THROUGH THE PERMEABLE PAVEMENT SITE. INSTALL
BARRIERS OR FENCES AS NEEDED.
B. IF THIS IS NOT POSSIBLE, PROTECT THE PAVEMENT PER THE CONSTRUCTION DOCUMENTS,
PROTECTION TECHNIQUES THAT MAYBE SPECIFIED INCLUDE MATS PLASTIC SHEETING.
BARRIERS TO LIMIT ACCESS, OR MOVING THE STABILIZED CONSTRUCTION ENTRANCE
C. SCHEDULE STREET SWEEPING DURING AND AFTER CONSTRUCTION TO PREVENT SEDIMENT
FROM ACCUMULATING ON ME PAVEMENT
10. AS-BUILT INSPECTION. AFTER INSTALLATION, ANAPPROPRIATELYLICENSEDNCDESIGN
PROFESSIONAL SHALL PERFORM AFINAL AS-BUILT INSPECTIONAND CERTIFICATION THAT
INCLUDES:
A. ENSURING THAT THE PAVEMENT IS INSTALLED PER THE PLANS AND SPECIFICATIONS.
B. ENSURING THAT THE SURFACE IS NOTDAMAGED, FREE FROM FINESAND SEDIMENT
C. CHECKING THATALL PERVIOUS SURFACES DRAIN AWAYFROM THEPAVEMENTAND THAT
SOIL AROUND THEPAVEMENT IS STABILIZED WITH VEGETATION.
D. PREPARING THE AS-BUILT PLANS THAT INCLUDE ANY CHANGES TO THE UNDERDRAINS
OBSERVATION WELL LOCATIONS, TERRACE LAYOUTS, AGGREGATE DEPTH OR STORAGE
STRUCTURES, ANY REVISED CALCULATIONS ETC.
E. TESTING THE PA VEMENT SURFACE PERMEABILITY USING THE NCSU SIMPLE INFILTRATION
TEST OR OTHER APPROPRIATE TEST SUCH AS ASTM Ci MI STANDARD TEST METHOD FOR
INFILTRATION RATE OFW-PLACE PERVIOUS CONCRETE.
F. ANY DEFICIENCIES FOUND DURING THE AS�BUILTWSPECTION SHALL BE PROMPTLY
ADDRESSED AND CORRECTED.
Stormwater Design Manual
C-5. Permeable Pavement
Permeable pavement captures stormwater through voids in the pavement surface and filters
water through an underlying aggregate reservoir. The reservoir typically allows the water to
infiltrate into the soil subgrade. The reservoir can also be designed to detain and release the
water to a surface conveyance system if the underlying soil is not suitable for infiltration.
The purpose of permeable pavement is to control the quality and quantity of stormwater
runoff while accommodating pedestrians, parking and possibly traffic (if adequate structural
support is provided). Permeable pavement is especially useful in existing urban development
where the need to expand parking areas is hindered by lack of space needed for stormwater
management. Permeable pavement is also useful in new developments with limited space
where land costs are high, and when nutrient reductions or green building certification
program are desired.
The design volume for an infiltrating pavement system is equivalent to the volume that is
stored in the aggregate and infiltrated into the ground within a 72 -hour period. The design
volume for a detention pavement system is the volume that is release slowly from the
aggregate for a two to five-day period.
Rule 15A NCAC 2H .1055. MDC for Permeable Pavement
SCM Credit Document, C-5. Credit for Permeable Pavement
C-5. Permeable Pavement 1 Revised: 4-6-2017
NCDEQ Stormwater Design Manual
Built -Upon Area Credit for Infiltratinq Pavement
Guidance on the MDC
MDC 1: Soil Investigation
MDC 2: SHWT Requirements
MDC 3: Siting
MDC 4:
Soil Subgrade Slope
MDC 5:
Stone Base
MDC 6:
Pavement Surface
MDC 7:
Runoff from Adjacent Areas
MDC 8:
Drawdown Time
MDC 9:
Observation Well
MDC 10:
Detention Systems
MDC 11:
Edge Restraints
MDC 12:
Grade When Dry
MDC 13:
Inspections and Certifications
Recommendations
Recommendation 1: Signage
Recommendation 2: Geogrids. Geotextiles and Geomembranes
Recommendation 3: Discussion with Owner
Recommendation 4: Consider Structural Strength
Construction
Maintenance
Old Versus New Desion Standards
Resources
Built -upon Area Credit for Infiltrating Pavement
Infiltrating permeable pavement that is designed per the MDC may be considered as 100%
pervious for the following purposes:
1. On new projects: As a tool to keep a project below the BUA threshold for high density or
to reduce the volume of the SCM that is treating the balance of the project.
2. On existing projects: As a tool to add a driveway, parking area, road, patio or other
paved area while still adhering to a BUA restriction imposed by development covenants,
SCM design or permit conditions.
The BUA credit for infiltrating permeable pavement cannot be used to create an exemption from
the permit requirements in 15A NCAC 02H .1019(2)(c) [Coastal Stormwater Requirements],
because the permeable pavement must be reviewed to determine whether it meets the MDC.
C-5. Permeable Pavement 2 Revised: 4-6-2017
NCDEQ Stormwater Desi
Figure 1. Permeable Pavement Example: Cross -Section (NCSU-BAE)
Pervious Concrete
or Porous Asphalt
Pervious Concrete (PC)
or Porous Asphalt
to Base
Permeable Interlocking
Concrete Pavers (PICP)
Pavers & No. 8
Stone in Openings
Bedding Course
Figure 2. Permeable Pavement Example: Outlet for Infiltration System (NCSU-BAE)
t tanh� dte u11Jn�;
Inlet slot at 0prern : cti'Gh
gi anized or stainiesB s!ea arak r•. - -*�`r 1 - ,
morn!nai grate opening, - ! 7'
44
uuchrraifreotwaid _--�, ';
rv!twfertrr7[�i5
.> W
Dt �..
ovUOnoi u!wMcf0rn Lwavtoos
J:icooua c*wtk for hwpass
(it laro6r Storms
+c4umea p*e sets L
Threaded cap for
iawaterrm &
maettenarce
LET
C-5. Permeable Pavement 3 Revised: 4-6-2017
NCDEQ Stormwater Design Manual
Guidance on the MDC
PERMEABLE PAVEMENT MDC 1: SOIL INVESTIGATION
For infiltrating pavement systems, site-specific soil investigation shall be performed to
establish the hydraulic properties and characteristics within the proposed footprint and at the
proposed elevation of the permeable pavement system.
Guidance on soil testing is provided in Chapter A-2.
PERMEABLE PAVEMENT MDC 2: SHWT REQUIREMENTS
The minimum separation between the lowest point of the subgrade surface and the SHWT
shall be:
(a) two feet for infiltrating pavement systems; however, the separation may be reduced to
no less than one foot if the applicant provides a hydrogeologic evaluation that
demonstrates that the water table will subside to its pre -storm elevation within five days
or less; and
(b) one foot for detention pavement systems.
Guidance on soil testing and hydrogeologic evaluation is provided in Chapter A-2.
PERMEABLE PAVEMENT MDC 3: SITING
Permeable pavement shall not be installed in areas where toxic pollutants are stored or
handled.
Permeable pavement shall not be used in areas where concentrations of oils and grease, heavy
metals and toxic chemicals are likely to be significantly higher than in typical stormwater runoff.
Installing permeable pavement in these areas increases the risk of these pollutants entering the
groundwater. Examples of development types that often include stormwater hotspots are listed
below. However, this is not a comprehensive list. Only the portion of the site where toxic
pollutants are stored or handled is considered a hotspot. For example, the parking lot of an
airport would not be a hotspot but the airplane hangar and maintenance areas are hotspots.
Table 1: Hot Spots Where Permeable Pavement may not be Appropriate
Fueling facilities SIC code "heavy" industries Commercial car washes
Fleet storage
Trucking & distribution centers
Vehicle maintenance areas
Solid waste facilities
Airport maintenance areas
Wastewater treatment plants
Racetracks
Railroads and bulk shipping
Public works yards
Road maintenance areas
Scrap yards
Landfills
C-5. Permeable Pavement 4 Revised: 4-6-2017
Care should be taken when implementing permeable pavement at redevelopment sites.
Stormwater shall not be infiltrated into contaminated soils because this can cause dispersion of
toxic substances to other sites and to groundwater. However, a permeable pavement system
designed for detention may work on a contaminated site. If the site history includes land uses
listed above, it shall be assumed that contaminated soils are present until detailed investigation
determines otherwise. If contaminated soils are present or suspected, the DEQ recommends
that the designer consult with an appropriately licensed NC professional.
PERMEABLE PAVEMENT MDC 4: SOIL SUBGRADE SLOPE
The soil subgrade surface shall have a slope of less than or equal to two percent.
Whether is the pavement is designed for infiltration or detention, it is crucial that the subgrade
be almost flat, i.e., less than or equal to a 2% slope. Besides maximizing infiltration, a flat
subgrade provides the most storage capacity within the aggregate base.
Terraces and baffles or graded berms can be used in the subgrade design to store stormwater
at different elevations for treatment. See Figure 3 below for a schematic configuration of
terraces and baffles in the subgrade. The plan drawing set shall include a separate subsurface
(subgrade) grading plan, especially for sites with baffles, berms or terraces.
Figure 3. Terraces and Baffles under Permeable Pavement. (NCSU-BAE)
. PrY
1'7/,•1
•Y y'yf
1`1 1 I:ri„�.,
•r sr •r •r •r •r • .r . . u;•
.
yr .y�j T��•��� •[� • Lf ift �• • � � . �,.
�F
• •T • rY ,rYTi d •� •T �ti i _rr wY�,� ,•Y o`r ►" • r �� �Y
..-ma=r: �I...:�.�q�sli'",.1'r'r1�'1��•y Iy1��
Iii
C-5. Permeable Pavement 5 Revised: 4-6-2017
NCDEQ Stormwater Design Manual '
PERMEABLE PAVEMENT MDC 5: STONE BASE
Washed aggregate base materials shall be used.
In addition to supporting the pavement system, the aggregate base stores the design storm
within its void spaces.for infiltration or detention and release. The size of the aggregate base
stone is selected by the designer based on the needs for structural strength and porosity. The
aggregate shall be washed and have 2% or less passing the ASTM No. 200 sieve. If the
aggregate is not washed, then the fines that are interspersed with it will eventually was to the
top of the subgrade and possibly clog the in-situ soils, preventing infiltration. The aggregate
supplier can likely provide the percentage of voids using ASTM C29 Standard Test Method for
Bulk Density ("Unit Weight') and Voids in Aggregate. The only way to be certain that the
aggregate has been washed is to be present on the site when it is delivered.
Equation 1 can be used to determine the depth of aggregate needed for the design volume.
Please note that the bedding layer of aggregated in a PICP system may not be used to provide
storage for the water quality storm.
Equation 1: Aggregate Depth for the Design Storm (Dw,j
Dwq = P(1+R)
n
where: Dwq = Depth of aggregate needed to treat the water quality storm (inches)
P = Rainfall depth for the water quality storm (inches)
R = Aa/AP, ratio of the additional BUA to permeable pavement area
N = Percent voids, unitless decimal (from ASTM C29)
PERMEABLE PAVEMENT MDC 6: PAVEMENT SURFACE
The proposed pavement surface shall have a demonstrated infiltration rate of at least 50
inches per hour using a head less than or equal to 4 inches.
The pavement surface should be selected based on the desired appearance and the types of
applied loads on the permeable pavement. Currently, the most widely used types of pavement
courses applied in North Carolina are Permeable Interlocking Concrete Pavers (PICP), Pervious
Concrete (PC) and Porous Asphalt (PA). Please note that PA and PICP are flexible pavement
and rely on structural support from the aggregate base.
Designers may propose other types of pavement surface and base courses but shall
demonstrate that the proposed design functions adequately hydraulically and structurally in the
long term. See Table 2 below for a summary of the most commonly used pavement courses
and some pros and cons of each.
C-5. Permeable Pavement 6 Revised: 4-6-2017
Table 2: Permeable Pavement Types
Permeable Interlocking PICPs are a type of unit paving system that drains water through joints
Concrete Pavers (PICP) between the pavers filled with small, highly permeable aggregates. The
Pervious Concrete (PC) PC is produced by reducing the fines in a conventional concrete mix with
other changes to create interconnected void spaces for drainage. Pervious
concrete has a coarser appearance than standard concrete although
mixtures can be designed to provide a denser, smoother surface profile
than traditional pervious concrete mixtures.
Pros: While not as strong as conventional concrete pavement, PC
provides adequate structural support, making it a good choice for travel
lanes or heavier vehicles in addition to parking areas and residential streets.
The National Ready Mixed Concrete Association provides a contractor
training and certification program. The American Concrete Institute
vv. publishes a construction specification and a report which provides guidance
on structural, hydrological and hydraulic system and component design in
addition to mix proportioning and maintenance.
Cons: Mixing and installation must be done correctly or PC will not
function properly. PC can be subject to surface raveling and deicing salt
degradation if not designed and constructed properly. Restoring surface
permeability after a significant loss of initial permeability may be difficult
without removing and replacing the surface course for the affected area.
C-5. Permeable Pavement 7 Revised: 4-6-2017
pavers are placed on a thin aggregate bedding layer over a thicker choker
course and base beneath. The choker course and aggregate base provide
�—� --J _
uniform support, water storage and drainage.
— i
Pros: Well suited for plazas, patios, small parking areas and stalls,
_
parking lots and residential streets. PICP can be designed for a significant
load of heavy vehicles and does not require curing time. As compared to PC
1
and PA, PICP is easier and less costly to renovate if it becomes clogged.
The Interlocking Concrete Pavement Institute offers a design guide,
r
construction specifications, design software, and a Certified PICP Specialist
Course for contractors.
Cons: PICP often has the highest initial cost for materials and installation.
Regular maintenance of PICP may be higher than PC and PA because of
the need to refill the joints with aggregate after cleaning and the greater
occurrence of weeds.
Pervious Concrete (PC) PC is produced by reducing the fines in a conventional concrete mix with
other changes to create interconnected void spaces for drainage. Pervious
concrete has a coarser appearance than standard concrete although
mixtures can be designed to provide a denser, smoother surface profile
than traditional pervious concrete mixtures.
Pros: While not as strong as conventional concrete pavement, PC
provides adequate structural support, making it a good choice for travel
lanes or heavier vehicles in addition to parking areas and residential streets.
The National Ready Mixed Concrete Association provides a contractor
training and certification program. The American Concrete Institute
vv. publishes a construction specification and a report which provides guidance
on structural, hydrological and hydraulic system and component design in
addition to mix proportioning and maintenance.
Cons: Mixing and installation must be done correctly or PC will not
function properly. PC can be subject to surface raveling and deicing salt
degradation if not designed and constructed properly. Restoring surface
permeability after a significant loss of initial permeability may be difficult
without removing and replacing the surface course for the affected area.
C-5. Permeable Pavement 7 Revised: 4-6-2017
Stormwater Desian Manual ■ t
Porous Asphalt (PA)
PA is like conventional (impervious) asphalt except that less fine material is
used in the mixture to provide for drainage, resulting in has a coarser
appearance than conventional asphalt. A modified asphalt binder as
specked by the Carolina Asphalt Pavement Association (CAPA) shall be
used to ensure long term durability and permeability.
Pros: While not as strong as conventional asphalt pavement, PA offers
sufficient structural strength for parking lots and streets. The National
Asphalt Pavement Association (NAPA) provides a design, construction and
maintenance guide for porous asphalt titled Porous Asphalt Pavement for
Stormwater Management. CAPA provides a Porous Asphalt Guide
Specification for the Carolinas. Training on PA for engineers and
contractors is available through CAPA. For information regarding the use of
PA and to obtain a list of qualified contractors, contact CAPA at:
www.carolinaasphalt.org.
Cons: Mixing and installation must be done correctly or PA will not function
properly. The owner, contractor and designer shall ensure that PA is not
confused with standard asphalt. Asphalt sealants or overlays that eliminate
surface permeability shall not be used. Restoring surface permeability after
a significant loss of initial permeability may be difficult without removing and
installing a portion of the surface course.
Concrete Grid Pavers CGPs are an "older cousin" to PICPs and have significantly larger openings
(CGP) filled with aggregates, sand, or topsoil and turf grass for infiltration. CGPs
are intended for limited vehicular traffic such as overflow parking (e.g.,
intermittent stadium parking), emergency access fire lanes around
buildings, and median crossovers. CGP is not recommended for regularly
q�used parking areas and for roads intended for PICP or PC.
Pros: CGP is less expensive than PICP and CGP can provide a grassed
surface. Design, construction and maintenance guidance is available from
the Interlocking Concrete Pavement Institute.
Cons: CGP is intended for limited vehicular traffic and overloaded
V pavements often experience differential settlement and paving unit damage.
CGP with grass requires mowing and may require watering, fertilizing and
re -seeding.
Plastic Turf Reinforcing
Grid (PTRG)
PTRG, also called geocells, consists of flexible plastic interlocking units that
infiltrate water through large openings filled with aggregate or topsoil and turf
grass. PTRG is well suited for emergency vehicle access over lawn areas or
overflow parking. PTRG is not approved for regularly used vehicular areas
such as parking lots or roadways where PICP or PC should be used.
Pros: Reduces expenses and maximizes lawn area.
Cons: PTRG has less structural strength than the other pavement course
options, especially when used under saturated conditions. Like CGP with
grass, it shall be mowed, sometimes fertilized and watered. Overuse can kill
the turf grass or create ruts from displaced aggregates. Also, sediment from
adjacent sources can damage the grass and accelerate clogging.
C-5. Permeable Pavement 8 Revised: 4-6-2017
lnmcNw,mlu!
Stonnwater Design Manual lug
For PC and PA, it is crucial to specify the proper mix design. For PC, the mix design shall be in
accordance with the latest version of ACI 522.1 Specification for Pervious Concrete. For PA,
the mix design shall be in accordance with NAPA's Porous Asphalt Pavements for Stormwater
Management and CAPA's Porous Asphalt Guide Specification. For PICP, PA and PC, the use
of certified and qualified contractors in accordance with industry standard documents shall be
required and noted on both project plans and specifications.
For all types of permeable pavement, follow manufacturer recommendations, product
standards, and industry guidelines to help ensure lasting installations. Manufacturer
requirements and industry standards shall be implemented in addition to (and not instead of) the
design requirements in this manual. Designers who propose to use a pavement surface other
than PICP, PC or PA shall demonstrate that the pavement will function adequately hydraulically
and structurally in the long term.
PERMEABLE PAVEMENT MDC 7: RUNOFF FROM ADJACENT AREAS
Runoff to the permeable pavement from adjacent areas shall meet these requirements:
(a) The maximum ratio of additional built -upon area that may drain to permeable pavement
is 1:1. Screened rooftop runoff shall not be subject to the 1:1 loading limitation.
(b) Runoff from adjacent pervious areas shall be prevented from reaching the permeable
pavement except for incidental, unavoidable runoff from stable vegetated areas.
Whether designed for infiltration or detention, permeable pavement systems may be designed
to treat additional BUA up to a 1:1 ratio (additional BUA to pavement area). For example, in the
parking lot shown below, the design could include parking stalls with permeable pavement
(shaded in light green) and the travel lanes (not shaded) with conventional pavement. The
design of the subgrade, aggregate base and underdrain would be tailored to handle the
additional stormwater runoff. Impervious areas may drain to the permeable pavement with
proper design of the pavement system per this chapter. Examples of areas that may be easily
diverted onto the permeable pavement include: travel lanes in parking lots, sidewalks, and roof
drains.
Roof downspouts may be directed to the permeable pavement surface, but it is the designer's
responsibility to ensure that downspouts are of a sufficient number and spacing to prevent
nuisance flooding. The downspouts may also drain directly into the permeable pavement base.
Downspout outlets or ground level impervious surfaces shall not drain more than 1,000 sf to a
single point onto the permeable pavement. The area of additional BUA draining to the
pavement shall not exceed the area of the pavement itself (in other words, a maximum 1:1 ratio
of additional BUA to pavement area).
To avoid pavement clogging, pervious areas such as lawns and landscaping shall not drain to
permeable pavement. Exceptions such as site restrictions on redevelopment projects will be
reviewed on a case-by-case basis. The site plan shall show pervious areas graded to flow
away from the pavement or include conveyances to route pervious surface runoff elsewhere.
C-5. Permeable Pavement 9 Revised: 4-6-2017
NCDEQ Stormwater Design Manual . 1%"�
PERMEABLE PAVEMENT MDC 8: DRAWDOWN TIME
Infiltrating permeable pavement systems shall be designed to dewater the design volume to
the bottom of the subgrade surface within 72 hours. In-situ soils may be removed and
replaced with infiltration media or infiltration media may be placed on top of in-situ soils if the
applicant provides a soils report demonstrates that the modified soil profile allows for
infiltration of the design volume within 72 hours.
Before determining drawdown time, the designer should first determine if the site is appropriate
for infiltration. In areas where in-situ soils become unstable when saturated, have high shrink -
swell tendencies or there is contamination of groundwater or soils, a detention system should be
used.
For infiltrating pavement, the designer may use the soil test results to calculate the drawdown
time for the depth of stormwater that will be conveyed to the pavement system using Equation 2
below.
T=
P(1 +R)
24*SF*i
Equation 2: Drawdown Time
where T = Drawdown time (days)
P = Depth of the design storm (inches)
R = Aa/AP, the ratio of additional BUA to permeable pavement area
SF = Safety factor (0.2)
1 = Measured in-situ soil infiltration rate (in/hr)
If the drawdown time exceeds three days, then the designer can reduce the amount of
additional BUA (if any) that drains to the permeable pavement and see if this decreases ponding
time to less than five days. Otherwise, the site will require a detention pavement system that
detains the stormwater for two to five days. For any site where the stormwater is not predicted
to infiltrate within 48 hours, the DEQ advises consulting a geotechnical engineer to ensure that
structural pavement design issues are properly addressed.
C-5. Permeable Pavement 10 Revised: 4-6-2017
NCDEQ Stormwater Design Manual
PERMEABLE PAVEMENT MDC 9: OBSERVATION WELL
Permeable pavement shall be equipped with a minimum of one observation well placed at
the low point in the system. If the subgrade is terraced, then there shall be one observation
well for each terrace. Observation wells shall be capped.
An observation well enables the owner to
measure the depth of standing water in the
permeable pavement system. Observation
wells shall be fitted with a lockable cap installed
placed even with the pavement surface to
facilitate quarterly inspection.
Observations of the water depth throughout the
estimated ponding time (T) indicate the rate of
water infiltration. The observation well shall
consist of a rigid 4 to 6 -inch diameter
perforated PVC pipe. The lower end of the
PVC pipe should be placed below the
elevations of the subgrade surface; therefore,
the elevation of water within the pipe will match
the elevation of water within the stone base.
Figure 4. Observation Well
PERMEABLE PAVEMENT MDC 10: DETENTION SYSTEMS
Pavement systems may be designed to detain stormwater in the Updated July 19, 2016
aggregate for a period of two to five days.
There are some compelling reasons to design a permeable pavement system for infiltration; it
will receive credit for BUA reduction plus a higher pollutant removal credit than a comparably
sized detention system. In addition, infiltrating systems are more compatible with a Low Impact
Development (LID) approach to stormwater because they can help maintain pre -development
hydrology. However, an infiltrating system will not work in all situations.
Figure 4. Permeable Pavement Example: Outlet for Detention System (NCSU-BAE)
Curb cuts sszad?wsafe bypass Appropsa.elp szed and
slabtAzed comeyance
of 10 -it, 24-tu storm Channel
urrl.rdt3.n
Opt anal
mperrneable I mng
C-6. Permeable Pavement 11
Orifice seed for
detention of +ator
qualRy roluma
I�
OUTLET
Revised: 4-6-2017
Storrnwater Desian Manual ■
PERMEABLE PAVEMENT MDC 11: EDGE RESTRAINTS
Edge restraints shall be provided around the perimeter of permeable interlocking concrete
pavers (PICP) and grid pavers.
Edge restraints are essential to the structural longevity of a PICP pavement system. Without
edge restraints, pavers can move over time and reduce the surface's structural integrity. As
pavers move, the joints open and pavers can be damaged. PC pavement systems provide
adequate structural edge support and do not require perimeter edge restraints. The structural
edge of PA systems can be enhanced by an edge restraint; they are recommended for PA, but
not required.
Figure 5. Edge Restraints on PICP
Edge restraints shall be flush with the pavement or somewhat higher than the pavement
surface. Edge restraints higher than the pavement surface help keep the stormwater on the
pavement and prevent stormwater run-on from clogging the permeable pavement. In addition to
providing structural support, the PICP can provide'an attractive edge. See Figure 6 below for
examples of acceptable edge restraints.
Concrete curb
extending to
bottom of
permeable
base
Aggregate
base
Figure 6. Edge Restraints: Example Cross -Sections
Permeable Conventional
C-5. Permeable Pavement 12 Revised: 4-6-2017
Stormwater
In addition to concrete edge restraints, an important consideration is the boundary between
permeable and conventional pavement. At intersections between permeable pavement and
conventional concrete, a geomembrane barrier should be provided to contain the stormwater
under the permeable pavement and protect the base and subgrade under the conventional
concrete. There should be a joint between the pavement surfaces for maintenance purposes.
At intersections between permeable pavement and conventional asphalt, a concrete curb that
extends below the permeable base should be provided to protect the subgrade under the
conventional asphalt. Concrete curbs provide more separation between the pavement courses,
which is helpful when the conventional asphalt is resurfaced. An alternative design option uses
a concrete curb to protect the asphalt and then an impermeable liner to separate the bases
under the asphalt and permeable pavement.
PERMEABLE PAVEMENT MDC 12: GRADE WHEN DRY
The soil subgrade for infiltrating permeable pavement shall be graded when there is no
precipitation.
Grading soils when they are wet is almost certain to cause a severe decrease in the soil
infiltration rate and might result in a failure of the permeable pavement system.
PERMEABLE PAVEMENT MDC 13: INSPECTIONS AND CERTIFICATIONS
After installation, permeable pavement shall be protected from sediment deposition until the
site is completed and stabilized. An in-situ infiltration permeability test shall be conducted
and certified on the pavement after site stabilization.
After installation, a final as -built inspection and certification should be performed that includes:
• Ensuring that the pavement is installed per the plans and specifications.
• Ensuring that the surface is not damaged, free from fines and sediment.
• Checking that all pervious surfaces drain away from the pavement and that soil around
the pavement is stabilized with vegetation
• Preparing the as -built plans that include any changes to the underdrains, observation
well locations, terrace layouts, aggregate depth or storage structures, any revised
calculations, etc.
• Testing the pavement surface permeability using the NCSU Simple Infiltration Test (see
Maintenance Section 18.6.4) or other appropriate test such as ASTM C1701 Standard
Test Method for Infiltration Rate of In -Place Pervious Concrete.
Any deficiencies that are discovered shall be promptly addressed and corrected.
C-5. Permeable Pavement 13 Revised: 4-6-2017
Recommendations
PERMEABLE PAVEMENT RECOMMENDATION 1: SIGNAGE
Provide signage to encourage proper maintenance of permeable pavement.
Signage at permeable pavement installations is required because they are maintained and
managed differently than traditional pavements. This promotes prolonged effectiveness and
helps prevent damage from conventional pavement management.
Figure 8 illustrates an example of a sign for a
permeable pavement location. The design is
based on a 24 by 18 in. standard size for sign
production.
The DEQ can provide this image in a high-
resolution file for owners who would like to use it
for their signs. This graphic is in color but color
signs are not required. Large permeable
pavement applications may require several
signs.
The owner should consider whether this sign
should also be provided in Spanish.
Figure 9. Example Sign Layout
PERMEABLE PAVEMENT
ACTIVITIES PROHIBITED:
SANDING
RE -SEALING
RE -SURFACING
POWER WASHING
STORAGE OF MULCH OR SOIL
STORAGE OF SNOW PILES
STORAGE OF HEAVY LOADS
APPLICATION OF SALT OR DE-ICERS
PERMEABLE PAVEMENT RECOMMENDATION 2: GEOGRIDS, GEOTEXTILES, AND
GEOMEMBRANES
Geogrids and geotextiles may be used in accordance with manufacturer and designer
recommendations. Geomembranes are not recommended on infiltration designs but may be
used on detention designs.
Not all permeable pavement applications include geogrids, geotextiles and geomembranes, but
some circumstances require their use. The advice of a licensed NC design professional with
experience in geotechnical design is a valuable resource in addition to the guidance provided
below.
Geogrids may be used at the top of the soil subgrade to provide additional structural support
especially in very weak, saturated soils. All manufacturer requirements shall be followed in the
design and installation.
Geotextiles (permeable) should line the sides of the aggregate base to prevent migration of
adjacent soils into it and subsequent permeability and storage capacity reduction. This problem
is more likely in sandy or loamy soils. Geotextiles are not recommended under the aggregate
base in an infiltration design because they can accumulate fines and inhibit infiltration.
Geomembranes (impermeable) should be used to accomplish the following:
• Provide a barrier on the sides and bottom of the aggregate base in a detention design to
prevent infiltration into the subgrade typically due to soil instability, the presence of
C-5. Permeable Pavement 14 Revised: 4-6-2017
stormwater hotspots, or potential for groundwater contamination. Geomembrane
barriers reduce the credit for TSS removal from 85% to 70%.
• Line the sides of the aggregate base whenever structure foundations or conventional
pavement are 20 feet or less from the permeable pavement (to avoid the risk of
structural damage due to seepage). The isolated use of geomembranes for this purpose
will not reduce the credit for TSS removal in the system.
PERMEABLE PAVEMENT RECOMMENDATION 3: DISCUSSION WITH OWNER
Before pursuing a permeable pavement design beyond the conceptual stage, the designer
shall verify site feasibility and meet with the owner to explain the installation, construction
and maintenance requirements of the proposed permeable pavement system.
The pavement's maintenance needs may require the owner to purchase new equipment or
contract with a new service provider. The required frequency of the maintenance may be
greater than conventional pavement in the same location. These costs are likely the same or
lower than other BMPs, but it is important to integrate maintenance requirements into the
owner's planning for site operations.
During the discussion with the owner, the designer shall confirm assumptions about the site use
and vehicle loading. For example, a parking lot primarily used by passenger cars may also see
bus traffic or a pedestrian area may also be driven on by service vehicles. These situations
require attention to structural design, specifically base, materials, thicknesses, soil strengths,
axle loads and repetitions.
PERMEABLE PAVEMENT RECOMMENDATION 4: CONSIDER STRUCTURAL
STRENGTH
The manual and rules do not provide structural design guidance of permeable pavements
subject to vehicular traffic. The designer shall ensure that the pavement meets its hydrologic
and structural goals by involving an NC licensed design professional with appropriate
expertise in pavement design.
Construction
A preconstruction meeting is highly recommended to ensure contractors understand the need to
prevent subgrade compaction and clogging of the pavement surface. The following should be
discussed at the meeting:
• Walk through site with builder/contractor/subcontractor to review erosion and sediment
control plan/stormwater pollution prevention plan
• Determine when permeable pavement is built in the project construction sequence;
before or after building construction, and measures for protection and surface cleaning
• Aggregate material storage locations identified (hard surface or on geotextile)
• Access routes for delivery and construction vehicles identified
G5. Permeable Pavement 15 Revised: 4-6-2017
• Mock-up location, materials testing and reporting
A preconstruction meeting is also an opportunity to discuss other unique construction
considerations for permeable pavement. Construction oversight by a design professional
familiar with permeable pavement installation can help ensure that the investment results in
adequate long-term performance.
Contractors not familiar with permeable pavement are accustomed to compacting pavement soil
subgrades to increase structural strength. However, this is in direct opposition to the correct
treatment of soil beneath permeable pavement for an infiltrating design.
Construction Step 1: Ensure Acceptable Conditions for Construction
Do not begin construction on permeable pavement until acceptable conditions are present. This
includes the following items:
• Pervious surfaces are graded so that they do not discharge to the permeable pavement,
except for instances when this is unavoidable, such as redevelopment projects.
• Impervious areas that will drain to the permeable pavement are completed.
• Areas of the site adjacent to the permeable pavement are stabilized with vegetation,
mulch, straw, seed, sod, fiber blankets or other appropriate cover in order to prevent
erosion and possible contamination with sediments.
• Construction access to other portions of the site is established so that no construction
traffic passes through the permeable pavement site during installation. Install barriers or
fences as needed.
• The forecast calls for a window of dry weather to prevent excess compaction or
smearing of the soil subgrade while it is exposed.
• All permeable pavement areas are clearly marked on the site.
Construction Step 2: Excavate the Pavement Area and Prepare Subgrade Surface
Clear and excavate the area for pavement and base courses while protecting and maintaining
subgrade infiltration rates using following these steps:
• Excavate in dry subgrade conditions and avoid excavating immediately after storms
without a sufficient drying period.
• Do not allow equipment to cross the pavement area after excavation has begun.
Operate excavation equipment from outside the pavement area or from unexcavated
portions of the area using an excavation staging plan.
See Figure 18-15.
• Use equipment with tracks rather than tires to minimize soil compaction when equipment
on the subgrade surface is unavoidable.
• Dig the final 9 to 12 in. by using the teeth of the excavator bucket to loosen soil and do
not smear the subgrade soil surface. Final grading or smoothing of the subgrade should
be done by hand if possible.
• Minimize the time between excavation and placement of the aggregate.
The final subgrade slope shall not exceed 0.5%. The slope of the subgrade shall be checked
before proceeding. Where possible, excavate soil from the sides of the pavement area to
minimize subgrade compaction from equipment. After verifying the subgrade slope, scarify,
rip or trench the soil subgrade surface of infiltrating pavement systems to maintain the soil's pre -
disturbance infiltration rate. These treatments must occur while the soil is dry. To scarify the
C-5. Permeable Pavement 16 Revised: 4-6-2017
tmr�irz;rvu
NCDEQ Stormwater Design Manual w�^
pavement, use backhoe bucket's teeth to rake the surface of the subgrade. To rip the
subgrade, use a subsoil ripper to make parallel rips 6 to 9 in. deep spaced 3 feet apart along the
length of the permeable pavement excavation as shown in Figure 18-16. In silty or clayey soils,
clean coarse sand must be placed over the ripped surface to keep it free-flowing (Brown and
Hunt 2009). The sand layer should be adequate to fill the rips.
An alternative to scarification and ripping is trenching. See Figure 18-17. If trenching, then
parallel trenches 12 in. wide by 12 in. deep shall be made along the length of the permeable
pavement excavation. Excavate trenches every 6 ft (measured from center to center of each
trench) and fill with'/ in. of clean course sand and 11'% in. of ASTM No. 67 aggregate (Brown
and Hunt 2009).
Ripped or trenched (uncompacted) soil subgrade can settle after aggregate base and surface
course installation and compaction. Therefore, base compaction requires special attention to
means and methods in the construction specifications and during construction inspection to
minimize future settlement from ripped or trenched soil subgrades.
Figure 10. Good Construction Practices, from left to right: Grading from the Side
(NCSU), Scarifying the Subgrade (Tyner), Trenching the Subgrade (Tyner)
Construction Step 3: Test the Subgrade Soil Infiltration Rate (Infiltration Systems Only)
Conduct a direct measurement of the soil's infiltration rate immediately after excavation and
before the aggregate is placed. Infiltration rate testing shall be conducted by an appropriately -
qualified professional. If the soil infiltration rate has diminished so that a 72 -hour drawdown
time is no longer possible, then rip or trench the subgrade further to restore the original
infiltration rate.
Construction Step 5: Place Geotextiles and Geomembrane (!f Applicable)
If using geotextiles or geomembranes, then follow the manufacturer's recommendations so for
the appropriate overlap between rolls of material. Secure geotextile or geomembrane so that it
will not move or wrinkle when placing aggregate.
C-5. Permeable Pavement 17 Revised: 4-6-2017
Manual
Construction Step 6: Place Catch Basins, Observation Well(s) and Underdrain System
Place the catch basins and observation
wells per the design plans and verify that
the elevations are correct.
If an upturned elbow design is used, then the
underdrains are placed first. See Figure 11.
In such case, verify the following:
• Elevations of the underdrains and
upturned elbows are correct.
• Dead ends of pipe underdrains are
closed with a suitable cap placed over
the end and held firmly in place.
• Portions of the underdrain system within
one foot of the outlet structure are solid
and not perforated.
Figure 11. Upturned Elbow (NCSU-BAE)
Construction Step 7: Place and Compact Aggregate Base
1-4
Inspect all aggregates to insure they are free of fines and conform to design specifications. If
aggregates delivered to the site cannot be immediately placed, then they should be stockpiled
on an impervious surface or geotextile to keep the aggregate free of sediment.
Before placing the aggregate base, remove any accumulation of sediments on the finished soil
subgrade using light, tracked equipment. If the excavated subgrade surface is subjected to
rainfall before placement of the aggregate base, the resulting surface crust must be excavated
to at least an additional 2 -inch depth, raked or scarified to break up the crust. For sites with an
impermeable liner or geotextiles, remove any accumulated sediments and check placement.
Slopes and elevations shall be checked on the soil subgrade and the finished elevation of base
(after compaction) or bedding materials to assure they conform to the plans and specifications.
Figure 12. Aggregate Placement and Compaction (NCSU-BAE)
S •L
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NCDEQ Stormwater Design Manual
All aggregate shall be spread (not dumped) by a front-end loader or from dump trucks
depositing from near the edge of the excavated area or resting directly on deposited aggregate
piles. Moisten and spread the washed stone without driving on the soil subgrade. Be careful not
to damage underdrains and their fittings, catch basins, or observation wells during compaction.
Follow compaction recommendations by the permeable pavement manufacturer or that from
industry guidelines. See Figure 12. Be sure that comers, areas around utility structures and
observation wells, and transition areas to other pavements are adequately compacted. Do not
crush aggregates during compaction as this generates additional fines that may clog the soil
subgrade.
Construction Step 8: Install Curb Restraints and Pavement Barriers
Edge restraints and barriers between permeable and impervious pavement shall be installed per
design. Before moving on to Construction Step 9, be certain that the design and installation are
consistent.
Construction Step 9: Install Bedding and Pavement Courses
The bedding and pavement course
installation procedures depend on the
permeable pavement surface. It is
important to follow the specifications and
manufacturer's installation instructions.
For PICP, a 4 in. thick choker course over
the base transitions to a 2 in. thick
bedding layer that provides a smooth
surface for the pavers. See Figure 13. The
bedding course shall be installed in
accordance with manufacturer or industry
guide specifications. Improper bedding
materials or installation can cause
significant problems in the performance of
the pavers and stone jointing materials
between them.
Figure 13. Upturned Elbow (NCSU-SAE)
If constructing a PICP pavement, use a contractor that holds a PICP Specialist Certificate from
the Interlocking Concrete Pavement Institute. A list of contractors can be obtained from the
Interlocking Concrete Pavement Institute.
PC pavements shall be constructed in accordance with the latest version of ACI 522.1
Specification for Pervious Concrete. Installation of PC may be accomplished using the One -
Step or the Two -Step method. The Two -Step method is more commonly used and it separates
the steps of strike -off from pervious concrete compaction. In this method, the pervious concrete
usually requires a more traditional, stiffer mix. The One -Step method uses a counter -rotating
roller screed to simultaneously strike -off and compact the pervious concrete. This method
requires pervious concrete with a more flowable mix so that the screed can more adequately
compact the mixture. Both methods require dense -paste pervious concrete mixtures. These
mixes are defined by chemical admixtures that reduce the viscosity of the cement paste so that
it will stick to and not run off the aggregates. The mixes provide greater cohesion that increases
strength and durability.
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Stormwater Design Manual
Figure 14. Compacting Pervious Concrete (NCSU-BAE)
If constructing a PA pavement, use a contractor that is qualified per Carolina Asphalt Paving
Institute (CAPA). In addition, be certain that the contractor follows the Design, Construction and
Maintenance Guide for Porous Asphalt (by the National Asphalt Pavement Association) in
conjunction with CAPA's Porous Asphalt Guide Specification, which will ensure that the binder
mix is appropriate for the North Carolina climate.
Construction Step 10: Protect the Pavement through Project Completion
If is preferable to have the permeable pavement installed at the end of the site construction
timeline. If that is not possible, protect the permeable pavement until project completion. This
shall be done by:
• Route construction access through other portions of the site so that no construction
traffic passes through the permeable pavement site. Install barriers or fences as needed.
• If this is not possible, protect the pavement per the construction documents. Protection
techniques that may be specified include mats, plastic sheeting, barriers to limit access,
or moving the stabilized construction entrance
• Schedule street sweeping during and after construction to prevent sediment from
accumulating on the pavement.
Maintenance
Like all other SCMs, permeable pavements require
maintenance to provide long-term stormwater
benefits.
As shown in Figure 15, the majority of maintenance
efforts are keeping the surface from clogging as well
as avoiding pollutants such as deicing salts that
might affect groundwater quality. Regular inspection
will determine whether the pavement surface and
reservoir are functioning as intended.
Figure 15. Clogged Pavement
C-5. Permeable Pavement 20 Revised: 4-6-2017
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NCDEQ Stormwater Design Manual
Directions for Maintenance Staff
Communication with maintenance staff is crucial regarding permeable pavement locations and
required management practices for keeping pavement unclogged. Maintenance staff must:
• Clean the surface with portable blowers frequently, especially during the fall and spring
to remove leaves and pollen before they irreversibly reduce the pavement's surface
permeability.
• Not stockpile soil, sand, mulch or other materials on the permeable pavement. Not
wash vehicles parked on the permeable pavement.
• Place tarps to collect any spillage from soil, mulch, sand or other materials transported
over the pavement.
• Cover stockpiles of same near the permeable pavement.
• Bag grass clippings or direct them away from the permeable pavement.
• Not blow materials onto the permeable pavement from adjacent areas.
• Not apply sand during winter storms.
• Immediately remove any material deposited onto the permeable pavement during
maintenance activities. Remove large materials by hand. Remove smaller organic
material using a hand-held blower machine.
• Remove weeds growing in the joints of PICPs by spraying them with a systemic
herbicide such as glyphosate and then return within the week to pull them by hand.
After the weeds are removed from paverjoints, the pavement shall be swept (with a vacuum
sweeper if possible) to remove the sediment and discourage future weed growth.
Future Construction Projects
If not properly managed, future construction projects on a permeable pavement site can convey
sediment to its surface. To prevent pavement clogging from future construction projects, the
owner or prime contractor shall insure that the contractors on the site:
• Route construction traffic away from the permeable pavement. Sediment from muddy
tire tracks can be deposited on the pavement and sometimes the equipment may
exceed the loading pavement loading capacity.
• Install and frequently inspect erosion and sediment controls.
• Inspect the site to insure new grading patterns do not result in the pavement receiving
run-on from landscaped areas especially with bare soil. If this occurs, then the site
requires regrading. After re -grading, disturbed areas shall be promptly stabilized with
vegetation.
• Schedule cleaning with a regenerative air or vacuum street sweeper during and after
construction.
Snow and Ice Management
Permeable pavement can be more effective at melting snow and ice than conventional
pavements. When snow and ice melts, the water infiltrates into the aggregate base rather than
staying on the pavement surface and refreezing. Therefore, light snow and ice accumulation
generally do not require removal. The base and soil act as a heat sink which helps drain water
before it freezes and slows the rate of surface freezing.
C-5. Permeable Pavement 21 Revised: 4-6-2017
NCDEQ Stormwater Design Manual
For larger accumulations of snowfall, sand shall never be applied on or adjacent to permeable
pavement to avoid surface clogging. In addition, pollutants such as deicing materials and
fertilizer shall not be applied to (non -grassed) pavement surfaces because these chemicals
infiltrate through the aggregate base to the subgrade and possibly to the groundwater.
PICP, PC and PA can be plowed like conventional 'pavements. For CGP and PTRG, the blade
should be set about 1 in. higher than usual to avoid damaging them. A rubber strip can also be
applied to the blade to protect them. Piles of plowed snow shall not be placed upon permeable
pavement surfaces to avoid concentrations of dirt and sediment when the snow eventually
melts.
Testing the Pavement Surface Infiltration Rate
The simplest way to see if permeable pavement is infiltrating rain is to look for puddles during
and after a storm. Permeable pavement should not have puddles; puddles are a sure sign of
surface clogging.
Because inspection and maintenance activities may not always coincide with rain events, NCSU
developed a simple infiltration test to evaluate pavement surface clogging severity and extent.
Simple Infiltration Test procedures are available at NCSU's Stormwater Group Web Site.
The Simple Infiltration Test shall be done on all permeable pavement applications at least one
time a year, except for single family residential lots with a total permeable pavement area of
under 2,000 sf. Whenever the Simple Infiltration Test indicates that maintenance is needed, the
design professional shall work with the owner to:
• Determine the cause of the permeable pavement clogging and correct it. Previous
sections with instructions for maintenance staff, future construction projects, and snow
and ice management may assist in evaluating the cause of clogging. Efforts to renovate
the clogged pavement are short lived unless the underlying problems are addressed.
• Vacuum the pavement in accordance with the next section.
• Check the observation wells to ensure that the pavement is not clogging beneath the
surface.
Surface Cleaning
Surface cleaning is required whenever puddles are present or surface infiltration testing
indicates that one or more areas on a permeable pavement application are clogged. DEQ
recommends vacuum cleaning the entire pavement area rather than only the clogged portion
since most of the expense is equipment mobilization. Owners are encouraged to clean PC and
PA on an annual, or more frequent basis, because surface infiltration is very difficult to restore
after it has become clogged, and the surface replacement is expensive.
The three main types of street cleaners are described below: mechanical, regenerative air and
vacuum. Vacuum or regenerative air street sweepers are required because they are effective at
cleaning the pore spaces in the pavement surface.
C-5. Permeable Pavement 22 Revised: 4-6-2017
Figure 16. Mechanical Sweeper
Figure 17. Regenerative Air Cleaner
(TYMCO, Inc.)
Figure 18. Vacuum Truck
(NCSU-BAE)
V
W ..
Mechanical sweepers are the most common. They
come in various sizes for cleaning pedestrian or
vehicular pavements, and they generally do not use
a vacuum. See Figure 16. They employ brushes that
initially move litter toward the machine center and lift
trash onto a conveyor belt for temporary storage
inside the machine. The brush bristles can penetrate
CGP, but not other types of permeable pavement.
For other pavement types, mechanical sweepers
may be used for removing trash, leaves, and other
organic material, but the mechanical sweeper is not
likely to be effective in removing sediment.
Regenerative air cleaners are the second most
common. They work by directing air at a high
velocity within a confined box the rides across the
pavement. The uplift from the high velocity
effectively loosens dust and other fine particles on
and near the pavement surface and lifts them into a
hopper at the back of the truck. This equipment
removes surface -deposited sediments from all
pavement types. This equipment is recommended
for regular preventive maintenance.
Vacuum street cleaners are the least common and
most expensive. They apply a strong vacuum to a
relatively narrow area that lifts particles both at and
below the surface of the pavement. Vacuum
sweepers have demonstrated their ability to suction
3 to 4 inches of gravel from PICP and can restore
infiltration to some types of pavements that have
been grossly neglected. (Hunt, NCSU-BAE)
Regular PICP cleaning requires operator adjustment of the vacuum force from regenerative air
equipment to minimize uptake of aggregate jointing materials. In some cases, the paver joints
may require refilling. In contrast, vacuum street cleaners have demonstrated their ability in
removing as much as 3 to 4 in. of aggregates from clogged PICP joints that have not received
any cleaning for years. This cleaning can restore surface infiltration for PICP as well for other
grossly neglected permeable pavement surfaces (Hunt NCSU-BAE).
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Inspecting Observation Wefts
The observation well allows the owner to determine how well the aggregate base and
underdrains are functioning. Follow these steps to inspect the observation wells:
• Wait five days after a rainfall exceeding 1 in. or 1.5 in. if in a Coastal County. If no
additional rain occurs in the five days, open each'observation well.
• Visually assess whether water is present. If visual assessment isn't possible, use a yard
stick or other water -level measurement method.
• If water is present, the soil subgrade is clogged and/or underdrains are not functioning.
Note the locations of the observation wells with water present.
• The owner (or site manager) should consult the designer or other appropriate professional
regarding possible remedies.
The designer or other appropriate design professional determines the actions needed to restore
the BMP so that it functions and achieves regulatory credit. For a detention system, this may
require repair of underdrains or other infrastructure. For an infiltration system, this shall require
subgrade infiltration rate investigation and may lead to redesign or replacement.
Pavement Cracking
Cracked areas shall be repaired using the same
materials as the original permeable pavement or, in
the case of PC and PA small areas can be replaced
with standard (impermeable) materials. The
impervious repaired area shall not to exceed 5% of
the total surface area. Figure 19 shows a small
concrete patch in a PC area. Larger repaired areas
shall be made from materials that infiltrate rain water
in a similar manner as the original surface.
Pavement that has buckled or shown major instability
may require a major renovation or replacement. In
this case, consult a pavement professional. Asphalt
sealcoats or overlays that eliminate surface
permeability shall not be used.
Required Operation and Maintenance Provisions
Figure 19. Pavement Patch
After permeable pavement is constructed, it shall be inspected once a quarter. The inspector
shall check each BMP component and address any deficiencies in accordance with Table 18-4
below. The person responsible for maintaining the permeable pavement shall keep a signed
and notarized Operation and Maintenance Agreement and inspection records. These records
shall be available upon request.
Once a year, the Simple Infiltration Test shall be performed and any deficiencies in surface
permeability shall be addressed.
C-5. Permeable Pavement 24 Revised: 4-6-2017
NCDEQ Stormwater
At all times, the pavement shall be kept free of:
— Debris and particulate matter through frequent blowing that removes such debris,
particularly during the fall and spring.
— Piles of soil, sand, mulch, building materials or other materials that could deposit
particulates on the pavement.
— Piles of snow and ice.
— Chemicals of all kinds, including deicers.
Table 3: Inspection Process and Required Remedies
The perimeter of the
permeable pavement
The surface of the
permeable pavement
Observation well
Educational sign
...How
to remediate the problem:
Areas of bare soil and/or
Regrade the soil if necessary to remove
erosive gullies
the gully, then plant ground cover and
water until established.
A vegetated area drains
Regrade the area so that it drains away
toward the pavement.
from the pavement, then plant ground
cover and water until established.
Trash/debris present
Remove the trash/debris.
Weeds
Do not pull the weeds (may pull out media
as well). Spray them with a systemic
herbicide such as glyphosate and then
return within the week to remove them by
hand. (Another option is to pour boiling
water on them or steam them.)
Sediment
Vacuum sweep the pavement.
Rutting, cracking or slumping
Consult an appropriate professional.
or damaged structure
Water present more than five
Clean out clogged underdrain pipes.
days after a stone event
Consult an appropriate professional for
clogged soil subgrade.
Missing or is damaged.
Replace the sign.
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Old Versus New Design Standards
The following is a summary of some of the changes in permeable pavement design standards
between the archived version of the BMP Manual and the current MDC for permeable
pavement. It is intended to capture the highlights only; any permeable pavement MDC that are
not captured in this table are still required per 15A NCAC 02H .1055.
Additional BUA directed to 1:1 maximum ratio between
1:1 maximum ratio; however,
permeable pavement pavement area and contributing
screened rooftop runoff is not subject
drainage area. Runoff from
to the 1:1 loading limitation. Runoff
pervious areas may not be
from pervious areas may not be
directed to pavement.
directed to pavement except for
small, unavoidable areas.
BUA credit Infiltrating permeable pavement in
Infiltrating permeable pavement
A and B soils considered to be
considered to be 100% pervious in
75% pervious, 25% impervious.
all soils
In C and D soils, considered to be
50% pervious, 50% impervious
Slope of the subgrade
surface
Minimum pavement
surface infiltration rate for
maintenance
Signage
Resources
May not be greater than 0.5%
Not specified
Required
May not be greater than 2%
50 inches/hour must be maintained.
Recommended
ACI Committee 522, Report on Pervious Concrete, American Concrete Institute, Farmington
Hills, MI, ACI 522R-10, March 2010.
Brown, R.A., Hunt, W.F., Urban Waterways., Improving Exfiltration from BMPs,
North Carolina Cooperative Extension, AG -588-17W, 2009
Hansen, K., Porous Asphalt Pavements for Stormwater Management, National Asphalt
Pavement Association, Information Series 131, Lanham, Maryland, 2008.
Hunt, W. F., Urban Waterways: Maintaining Permeable Pavements, North Carolina
Cooperative Extension, Raleigh, NC, AG -588-23, 2008
C-5. Permeable Pavement 26 Revised: 4-6-2017
en..>rn�.n�"•
Stormwater Design Manual
Leming, M. L., Malcom, H. R., and Tennis, P. D., Hydrologic Design of Pervious Concrete,
EB303, Portland Cement Association, Skokie, Illinois, and National Ready Mixed Concrete
Association, Silver Spring, Maryland, USA, 2007.
Smith, D.R., Permeable Interlocking Concrete Pavements, Fourth Edition, Interlocking Concrete
Pavement Institute, Herndon, Virginia, 2011.
Tyner, J. S., W. C. Wright, and P. A. Dobbs. 2009. Increasing exfiltration from pervious concrete
and temperature monitoring. J. Environ. Manage. 90(8): 2636-2641.
C-5. Permeable Pavement 27 Revised: 4-6-2017
COUNTY TAX I D#
Parcel
Mail/Box to:
This instrument was prepared
Brief description for the Inde)
THIS DEED made this 7A day of November,
GRANTOR
Jennifer SchubKleyenstuber (Separated)
(a/IJu Jennifer Schulz)
PO Box 1048
Spring Lake, NC 28390-1048
T. —
I0 02667&
FOtt
Oa:
SPECIAL WARRANTY DEED
**Free trader status, see
Separation Agreement filed w/
Consent Order 10CVD651,:Harnett Co.
ADVICE GIVEN
WEDS
County on the _ day of 20
(Title Ins. w/ Charter Title,
.M ..Z. Ame-tteville, NO
GRANTEE
ph uHHoldings, LLC (a North Carolina limited
118ility company)
9 wood Avenue
Fa eville, NC 28314
Enter in appropriate block for each Grantor and Grantee: name, mailing ad s, yad;1('appropriate, character of entity, e.g.
corporation or partnership.
The designation Grantor and Grantee as used herein shall include said parties,�heichLiys sucye�s�, and assigns, and shall include
singular, plural, masculine, feminine or neuter as required by context. I
WITNESSETH, that the Grantor, for a valuable consideration paid by the Grantee, theeipi of wh clyiereby acknowledged, has and
by these presents does grant, bargain, sell and convey unto the Grantee in fee simple, all *at Wrtpin lot orweel of land situated in the
City of ---------------,Spout Springs Township,11amenC`o�ty,Norey6kand mom particularly
described as follows:
SEE ATTACHED EXHIBIT'A'
The property hereinabove described was acquired by Grantor by instrument recorded in Estate File 10 E 147 afiq tg�k;?0W Page
100.
All or a portion of the property herein conveyed ____ includes or X does not include the primary residence ofGrSn 1
NC Bar Association Form No. 6 ® 1/12010
Printed by A =neat with the NC Bu Association
l��
A
that
IN WITNESS
the above described property is recorded in Plat Book page
Print/Type Name &
Printll'ype Name &
Print/Type Name &
the aforesaid lot or parcel of land and all privileges and appurtenances thereto belonging to the Grantee in
arts with the Grantee, that Grantor has done nothing to impair such title as Grantor received, and Grantor will
title against the lawful claims of all persons claiming by, under or through Grantor, other than the following
Ad Valorem taxes which Grantee agrees to pay in full when due.
(other than }dens)
covenants, rights-of-way and encumbrances that are disc osed on the public record and/or
ccurate survey of the property. A /
executed the foregoing as of the day and year
State of County of C4
I, the undersigned Notary Public of the Count}
JJenniier Schulz-YIUAnstuber (aWs Jennifer Schulz) pbl
foregoing instrument for the purposes therein expressed.
My Commission Expires: 21 13
(Affix Seal)
NC Bar Association Form No. 6 ® M/2010
Printed by Agreement with the NC Bar Association
Jennifer Schulz)
y (SEAL}
Print/Type Name:
(SEAL)
Print/Type Name:
(SEAL)
Print/Typs Name:
of JTZi 1 � and State aforesaid, certify that
tppe�r beforbine this day and acknowledged the due execution ofthe
-,, y han�&*d N4taeial stamp or seal thisn±* day November, 2011.
or Tvoed Name
Fled For Reglatratlon:
Book:
Document No.:
NC REAL ESTATE EXCISE TAX:
Recorder:
RE 29M,
2011016678
DEED 4
$3,100.00
'STN C pltq-!�O'
Y S. HARGROVE
F DEEDS, HARNETT
;LIUS HARNETT BLVD
UITE 200
TON_ NC 27846
52�00�'
TRUDI S WESTER
State of North Carolina, County of Harnett
VJMSERLY S. HARGROVE , REGISTER OF DEEDS
f I
DO NOT DISCARD ,
2011016678
an iron stake at the point of intersection of the South line of a 150 foot right-of-way of
No. 87 and the western line of the easternmost access road on the South side of
rn on plat of Babcock Lumber Company property made January, February and
ier Ekes, R.S. and running thence as the western line of said access road South
*k -W75 feet to an iron pipe and the line of property of North Carolina Pulp
1ife Norm 57 degrees 09 minutes West 1214 feet to an iron pipe in said line;
i oliite5 East 475 feet to an iron pipe in the Southern right-of-way line of
No, i7, t# once as said right-of-way line South 57 degrees 09 minutes East 1214
IINfenta(ning 13.24 acres and being the same property as described as Tract
4/m. r ag@I al d wife, Carletta R. Cagel to Ralph M. Hardin and wife, Anna M.
Hardin, dated the 29h
d except pr
Simple Deed
of record in Book 525, Page 67, of the Harnett County
Grantor also conveys to Grantee
Lot 4 (2.94 acres), and Lot 5 ((
duly recorded in Map #2011, Pa(
County Registry. if there is a
property as described on said F
and bounds above (13.24 acres),
in this Special Warranty Deed s
bounds description set forth at
Department
1331, Page
Transportation
aforesaid
acres),
on plat
Harnett
en subject
scribed by metes
warranties as contained
P,d to the metes and