SW8980504_Historical File_20100614

5041-3 Main Street �Q - 14'?14ti Phone: [phone]
Shallotte, NC 28470 Fax: [phone]
www.CompassPointeEngineering.com � Email: [e-mail]
1l
Thursday,May 27,2010
Mr. Chris Baker
NCDENR,DWQ
127 Cardinal Drive Extension
Wilmington,North Carolina 28403
Subject: Stormwater Permit No. SW8980504 Modification
3rd and 4th Street Extension,Town of Ocean Isle Beach
Dear Mr.Baker:
We have revised the design documents for the subject project based on DWQ's May 25,2010 letter
to Mayor Smith. Thank you for meeting with me on May 26, 2010 to go over the particulars of the
review comments.
Enclosed you will find:
1. Two copies of revised Plan Sheet C-8. This sheet now illustrates four drainage areas with a
table revised to reflect updated BUA and DA values.
2. Two copies of revised Plan Sheet C-7 that include revisions to the details for the driveway
trench systems, said revision incorporating a channel to intercept water from the roadway
and direct it to the infiltration swale system.
3. Two copies of revised page 2 of the Application Form presenting data for Drainage Areas 1
and 2.
4. Two copies of revised Supplement to Page 2 of the Application Form presenting data for
Drainage Areas 3 and 4.
5. One copy of revised Infiltration Basin Supplement for Drainage Area 1 —North Side Road.
6. One copy of revised Infiltration Basin Supplement for Drainage Area 2—South Side Road.
7. One set of revised calculations for the roadside swale systems (Drainage Areas 1 & 2) and
new calculations for the "interceptor channels"where the driveways connect to the edge of
pavement.
We appreciate your attention to this matter. Please contact us should you have any questions or
comments.
Sincerely,
RECEIVEIa
MAY 28MO
Donald M.Covil,P.E.
Compass Pointe Engineering,P.A. BY:
Enclosures
cc: Mr. Larry Sellers,Assistant Town Administrator,Town of Ocean Isle Beach
LAND PLANNING & SITE DESIGN • WATER • WASTEWATER • STORMWATER • EROSION CONTRO

CALCULATIONS AND NOTES
Ocean Isle Beach 3rd and 4th Street Extension
Stormwater Management Plan Renewal/Modification
DWQ Permit No. SW 8 980504
March 2010
Revised April 2010
Revised May 2010
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Channel Report
Hydraflow Express by Intelisolve Thursday,May 27 2010,9:32 AM
OIB 3rd & 4th Street
Triangular Highlighted
Side Slope (z:1) = 3.00 Depth (ft) = 0.09
Total Depth (ft) = 1.00 Q (cfs) = 0.070
Area (sqft) = 0.21
Invert Elev (ft) = 100.00 Velocity (ft/s) = 0.34
Slope (%) = 0.10 ' Wetted Perim (ft) = 4.61
N-Value = 0.015 Crit Depth, Yc (ft) = 0.06
14 '`` "°s " Top Width (ft) = 4.59
Calculations re a>A EGL (ft) = 0.09
Compute by: Known Q
Known Q (cfs) = 0.07
Elev (ft)
Section Depth (ft)
102.00 2.00
101.50 1.50
101.00 - 1.00
100.504,8
- 0.50
$ V
100.00 0.00
99.50 -0.50
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Reach (ft)

ATA
NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue C.oleen H.Sullins Dee Freeman
Governor Director Secretary
May 25, 2010
Debbie S. Smith, Mayor
Town of Ocean Isle Beach
3 West 3rd Street
Ocean Isle Beach, NC 28469
•
Subject: Request for Additional Information
Stormwater Project No. SW8 980504MOD
Ocean Isle Beach 3rd &4th Street Extension
Brunswick County
Dear Mrs. Smith:
The Wilmington Regional Office received andme accepted a modified State Stormwater Management
Permit Application for Ocean Isle Beach 3 & 4 Street Extension on May 22, 2010. A preliminary in-
depth review of that information has determined that the application is not complete. The following
information is needed to continue the stormwater review:
1. Please provide a drainage area map that clearly shows'all drainage areas as reported
on the stormwater application.
2. Please label the drainage areas on the application so that they can be identified in
concert with the drainage areas as presented on the plans.
3. The fourth drainage area shown on the application contains an error in the reported
drainage area and built-upon-area (BUA), please correct.
4. Please label the drainage areas on the supplemental forms so that they can be
identified with the drainage areas as shown on the drainage area plan.
5. One of the supplemental forms lists 35 driveways to be treated. The plans indicate 36
driveways to be treated, please correct.
6. Provide a detail that shown hoe the offsite stormwater runoff will be routed around the
driveway area to be treated in the driveway trenches.
7. Be sure to update the various tables and calculations with the revised drainage areas,
BUA's, etc.
Please note that this request for additional information is in response to a preliminary review. The
requested information should be received in this Office prior to June 25, 2010, or the application will
be returned as incomplete. The return of a project will necessitate resubmittal of all required items,
including the application fee.
Wilmington Regional Office
127 Cardinal Drive Extension,Wilmington,North Carolina 28405 One
Phone:[phone] FAX:[phone] I Customer Service:1-877-623-6748 No tCcZ$olina
Internet www.ncwaterqualilp.org /I,ftlyd,I`10

Debbie S. Smith
May 25, 2010
Stormwater Application No. SW8 980504MOD
If you need additional time to submit the information, please mail, email or fax your
request for a time extension to the Division at the address and fax number at the bottom
of this letter. The request must indicate the date by which you expect to submit the
required information. The Division is allowed 90 days from the receipt of a completed
application to issue the permit.
The construction of any impervious surfaces, other than a construction entrance under
an approved Sedimentation Erosion Control Plan, is a violation of NCGS 143-215.1 and
is subject to enforcement action pursuant to NCGS 143-215.6A.
Please reference the State assigned project number on all correspondence. Any
original documents that need to be revised have been sent to the engineer or agent. All
original documents must be returned or new originals must be provided. Copies are not
acceptable. If you have any questions concerning this matter please feel free to call me
at [phone] or email me at chris.baker©ncdenr.gov.
Sincerely,
G h k ,
Chris Baker
Environmental Engineer.II
GDS/csb: S:IWQSISTORMWATERIADDINFO120101980504MOD.may10
cc: Don Covil, P. E., Compass Pointe Engineering, P. A.
Wilmington Regional Office Stormwater File
Page 2 of 2

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Lewis,Linda
From: Johnson, Kelly
Sent: Wednesday, May 19, 2010 11:32 AM
To: Lewis,Linda; Bennett, Bradley; Patterson, Robert; Scott, Georgette;Vinson, Scott
Subject: RE: Design Storm
This came up with 3rd&4th Street extension last year(and it is in for another mod now), and we decided at that time
that the new BUA would be at 1.5".
From: Lewis,Linda
Sent: Wednesday, May 19, 2010 11:26 AM
To: Bennett, Bradley; Patterson, Robert; Scott, Georgette; Vinson, Scott; Johnson, Kelly
Subject: Design Storm
I am reviewing a high density project that was originally permitted in 1998 for an infiltration system. The volume
calculations were done assuming that the entire project area was 100% impervious, at a 1.5" design storm.
Now they are adding more BUA, and my question is, does the new BUA have to be accounted for at the larger
design storm?
Since the original project already used 100% impervious, the size of the infiltration system does not need to be
increased. I think we could look at this as a minor modification since the original permit already accounted for
the whole project at 100%.
Any concerns with just keeping the design storm at the previously permitted 1.5"? It is SA waters.
Linda
Please note my new email address is [e-mail]
Linda Lewis
NC Division of Water Quality
127 Cardinal Drive Ext.
Wilmington, NC 28405
910-796-7215
E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and may
be disclosed to third parties.
1

5041-3 Main Street 0 ADs Phone: [phone]
Sallotte, NC 28470 Fax: [phone]
www.CompassPointeEngineering.com 4 Email: [e-mail]
RECEIVED
APR 19 2010
Friday,April 16,2010
Ms.Kelly Johnson,Environmental Engineer
NCDENR,DWQ
127 Cardinal Drive Extension
Wilmington,North Carolina 28403
Subject: Stormwater Permit No. SW8980504 Modification
3rd and 4th Street Extension
Town of Ocean Isle Beach
Dear Ms.Johnson:
Thank you for you assistance and guidance in our efforts to modify the OIB 3'? & 4`"Street
Extension project relative to the treatment of the portions of driveways within the right-of-way
contiguous to lots covered under The Resort stormwater projects (DWQ No. SW8 051007 and No.
SW8 051008). We have revised the plans and related documents based on our numerous
conversations and emails. The enclosed Stormwater Narrative explains the approach we took.
Along with the narrative we have enclosed:
1. Two copies of revised page 2 of the Stormwater Management Permit Application Form;
2. Two copies of a supplement to page 2 of the Stormwater Management Permit Application
Form providing information relative to Drainage Area 3;
3. Revised Infiltration Basin Supplement for DA # 1 addressing the roadside infiltration
swales;
4. Revised Infiltration Trench Supplement for DA#2 addressing the individual driveway rock
trench systems for lots north of 3rd & 4th Street, said system being identical for each of the
42 future lots;
5. Revised Infiltration Trench Supplement for DA#3 addressing the individual driveway rock
trench systems for lots south of 3rd & 4th Street, said system being identical for each of the
36 future lots;
6. Revised Infiltration Trench Supplement for DA # 2 & 3 combined addressing the
cumulative driveway rock trench systems for the 78 future lots;
7. One set of revised project calculations; and,
8. Two sets of revised project plans.
It is noted that the roadside infiltration swales and the 78 driveway infiltration trench systems are
designed to handle the 10 year, 24 hour rainfall with no overflow at Y2 the infiltration capacity,thus
providing the basis for waiving the requirement for offline bypasses and vegetated filter strips. The
requirement that the driveway infiltration trenches be constructed per the design details will be by
legal instrument developed and enforced by the Town of Ocean Isle Beach.
LAND PLANNING & SITE DESIGN • WATER • WASTEWATER • STORMWATER • EROSION CONTROL

Ms.Kelly Johnson 2 April 16,2010
Ocean Isle Beach 3rd&4th Street Extension
Also, please note that item 6 above addresses the same project elements as presented under items 4
and 5. Items 4 and 5 provides information relative to a single trench system (since all trench
systems on the respective side of the road, whether north or south, are identical) and Item 6
provides information relative to the 78 trench systems considered collectively. It may be that you
do not need all three supplements; however, we wanted to be sure we were covered relative to this
element of the project.
We appreciate your attention to this matter. Please contact us should you have any questions or
comments.
Sincerely,
Donald M. Covil,P.E.
Compass Pointe Engineering,P.A.
Enclosures
cc: Mr.Larry Sellers,Assistant Town Administrator,Town of Ocean Isle Beach

STORMWATER PLAN NARRATIVE
Ocean Isle Beach 3rd and 4th Street Extension
DWQ Stormwater Permit No. SW8980504 Modification
APR VEb
Compass Pointe Engineering, PA B , g low
Y.
April 2010
DWQ issued high density SW Permit Number SW8 980504 Modification for this project on April 30,
1999. The original project included a 20'wide roadway, whereas a 20'wide roadway with 5' bike lanes on
each side was subsequently constructed. The Town of Ocean Isle Beach retained Compass Pointe
Engineering (CPE)to prepare plans and documentation for a renewal (due to a 10-year renewal period)
and a modification (since the paved roadway is 10'wider than that covered by the original permit). CPE
performed the work to reflect the wider roadway and submitted the project to DWQ for approval. DWQ
issued the permit via an approval letter on August 3, 2009.
Subsequent to the August 3 approval, it was discovered by the Town of Ocean Isle Beach that there
existed overlaps of State SW permits between 3rd &4th Street Extension and The Resort projects. The
Resort permits included one of high density(SW8 051007)and one of low density (SW8 051008). The
permits for both projects for The Resort included language stating that the maximum BUA allowed
"includes any built-upon area constructed within the lot property line and that portion of the right-of-way
between the front lot line and the edge of the pavement". The 3rd &4th Street Extension project included all
area within the right-of-way; thus, the overlap exists. In all, 48 lots along 3rd and 4th Street from the Troy
Street intersection to the end of the project(approximate station 34+50)were affected. Of the 48 lots, 5
are currently developed and have existing driveways. The remaining 43 are"future".
The Town, subsequent to discovering the overlap, directed CPE to modify the stormwater
management design documents for 3rd&4th Street Extension to the extent that no overlap would exist
between it and The Resort projects. CPE performed the requested work. Subsequent discussions with
staff at DWQ-Wilmington, however, led to the approach that the portion of the driveways within the R/W for
lots contiguous to"The Resort" remain a part of the 3rd and 4th Street Extension project. Future, it was
decided by the Town that all driveways (whether or not contiguous with "The Resort" lots) be treated with
independent, infiltration trench systems.
The following summarizes the key elements of the revised approach taken by CPE on behalf of the
Town.
1. Both Resort projects are to remain as currently permitted.
2. All driveways within the 3rd&4th Street Extension right-of-way, whether or not contiguous with "The
Resort" lots, are to be a part of the 3`d &4th Street Extension project.
3. All"future"driveways are to be served by independent, infiltration trench systems.
4. The main roadway, all"existing"driveways, and the portion of Oxford Street within the projected
R/W of 3rd&4th Street are to be served by the roadside infiltration swales.
5. The portions of Troy Street, Shelby Street and Sea Turtle Path that are within the projected R/W of
3rd&4th Street are to remain with"The Resort" Project Number SW8 051007 since the BUA for
these streets are included in said project.
1

Given the above, the current project is assigned two drainage areas-one for the stormwater
infiltration swales and one for the driveway stormwater infiltration trenches.
The calculations treat the entire area between the right-of-way lines (swales included) as
impervious even though the actual BUA:DA is 84.5%. This was done because the rainfall would fall
directly on the surface of the infiltration swales as well as on built-upon surfaces. Further, an additional
conservative element was incorporated during design in that the entire 1 '/" rainfall was used as the
treatment volume(i.e., the BMP Manual "Simple Method"was not used to reduce the"runoff" amount).
The soils within the swale and infiltration trench areas are sand with an estimated infiltration
capacity in excess of 20 inches/hour as established with the original submittal that was subsequently
permitted by DWQ. The runoff into the swales will be stored "in-place" due to the placement of soil dams
and driveway headwalls.
The calculations demonstrate that the swales are not only adequate to store and infiltrate without
discharge the runoff from the first 1 %" of rainfall but also are adequate to store and infiltrate without
discharge the runoff from the 1-year, 24-hour storm. Further, it is demonstrated that the infiltration swales
will handle the 10-year, 24-hour rainfall without discharge at 1/2 the reported infiltration rate; thus,
compliance with alternate design criteria is established for the waiving of offline bypass and vegetated filter
requirements.
This project drains to Eastern Channel, Old Sound Creek which in turn drains to the Atlantic
Intracoastal Waterway(AICW). The stream classification for the AICW at this point is SA.
There are no wetlands within the project boundary.
The Town of Ocean Isle Beach will enact a driveway ordinance to ensure that driveways within the
right-of-way where the infiltration trenches are required will contain language with the following restrictions:
• The maximum obstruction width within the roadside swale to construct the driveway will be 35'for
driveways on the northern side of 3id& 4th Street Extension and 36'for driveways on the southern
side.
• An infiltration trench system will be constructed as illustrated on the permitted plans.
• No culverts or other means of piping or channeling under the driveway will be constructed.
• No runoff from the lot shall be allowed to enter the trench infiltration system or the roadside
infiltration swales.
• Elevation of the top of the headwalls on each side of the driveway within the roadway right-of-way
shall be no lower than the elevation of the roadway center-line less 0.3
2

Supplement to Page 2, Section I11.8
of STORMWATER MANAGEMENT PERMIT APPLICATION FORM
for
Ocean Isle Beach 3rd &4th Street Extension—Modification
Town of Ocean Isle Beach,NC
April 2010
Basin Information Drainage Area 3
Receiving Stream Name Eastern Channel, Old Sound Creek
Stream Class & Index No. SA;HQW 15-25-6
Total Drainage Area (sf) 19,440
On-Site Drainage Area (sf) 19,440
Off-Site Drainage Area (sf) 0
Existing Impervious Area (sf) 0
Proposed Impervious Area (sf) 19,440
% Impervious Area (total) 100
Impervious Surface Area Drainage Area 3
On-site Buildings (sf) 0
On-site Streets (sf) 0
On-site Parking (sf) 0
On-site Sidewalks (sf) 0
Other On-site (sf) 19,440
Off-site (sf) 0
Total (sf) 19,440
RECEIVED
APR 19 2010
BY:

Supplement to Page 2, Section I11.8
of STORMWATER MANAGEMENT PERMIT APPLICATION FORM
for
Ocean Isle Beach 3rd & 4th Street Extension—Modification
Town of Ocean Isle Beach,NC
April 2010
Basin Information Drainage Area 3
Receiving Stream Name Eastern Channel, Old Sound Creek
Stream Class & Index No. SA;HQW 15-25-6
Total Drainage Area (sf) 19,440
On-Site Drainage Area (sf) 19,440
Off-Site Drainage Area (sf) 0
Existing Impervious Area (sf) 0
Proposed Impervious Area (sf) 19,440
% Impervious Area (total) 100
Impervious Surface Area Drainage Area 3
On-site Buildings (sf) 0
On-site Streets (sf) 0
On-site Parking (sf) 0
On-site Sidewalks (sf) 0
Other On-site (sf) 19,440
Off-site (sf) 0
Total (sf) 19,440
RECEIVED
APR 192010
BY:

Johnson, Kelly
From: Lewis,Linda
Sent: Monday, April 12, 2010 10:12 AM
To: Michael Norton; Don Covil
Cc: Johnson, Kelly
Subject: RE: 3rd &4th St Extension
Michael:
I believe that comment was geared toward the rule requirement to size the BMP for all of the impervious
surfaces that are (or will be) located within the drainage area of the BMP.
After looking at the old permit for 3`d &4th Street Extension, and the 2005 permits for The Resort and
discussing this with Kelly, there are a few things to consider regarding the original low density permit for
051007 and the high density permit for 051008.
The 3`d &4th Street high density infiltration permit was issued about 7 years before the permits for The Resort
at Ocean Isle Beach were issued. The original 3rd and 4th Street Extension permit accounted for 96 driveways
within the right-of-way, each 16'wide. The reviewer of the 2005 Resort permits may not have been aware of
the 1998 road permit. Some of the driveways under the road permit may have been double-counted under The
Resort permits.
Most of the permits we write include the road right-of-way as project area. The Resort was different because
the 3`d &4th Street right-of-way was not included in either of The Resort's low or high density permits. The lot
BUA assigned under The Resort permits, by definition, includes that portion of the driveway that is built from
the lot property boundary to the edge of the road. For the high density portion of The Resort, the trenches were
designed for 3500 sf of BUA per lot. This means that all of the lot BUA was intended to be collected and
treated, which would necessarily include the portion of the driveway that crossed the right-of-way.
However, there is a lot BUA discrepancy between the calculations and application (@3500) and the signed
deed restrictions and permit (@3600). We will attempt to verify if this is a typographical error and that the
driveways are appropriately graded.
In order to allow the removal of the driveways from the Road Extension permit, we would need to know that the
existing driveways are graded to drain back into the lots, and we would need to get a new deed restriction
statement for The Resort which corrects the BUA per lot and which dictates that the grade of those driveways
has to be sloped back into the lot to be picked up and treated by the permitted infiltration trench system for The
Resort.
Where those driveways are not graded to drain back into the lots, and those driveways will drain into the
proposed road BMP, then those driveways have to be included as BUA when sizing the road BMP.
Linda
Please note my new email address is [e-mail]
Linda Lewis
NC Division of Water Quality
127 Cardinal brive Ext.
Wilmington, NC 28405
910-796-7215
i

E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and may
be disclosed to third parties.
From: Michael Norton [mailto:[e-mail]]
Sent: Friday,April 09, 2010 1:43 PM
To: Lewis,Linda
Subject: Re: 3rd &4th St Extension
Hi Linda,
Kelly& I spoke on these last two items(see her last email below). The first one(#2 below) is covered. The second one
(#5) remains unclear and she suggested you may be able to offer further input for clarification. Please call on this one if
you can to help us understand what is needed to complete the modification. We hope to finish up so the Town can
complete construction prior to seasonal traffic issues.
Thanks,
Michael
Michael A.Norton
Compass Pointe Engineering,PA
5041-3 Main Street
Shallotte,NC 28470
910.755.5872 office
910.367-6869 cell
910.755-5875 fax
[e-mail]
www.compasspointeengineering.com
Original Message
From: Johnson. Kelly
To: Michael Norton
Cc: Don Covil ; Lewis,Linda ; Larry Sellers
Sent: Tuesday, April 06, 2010 12:12 PM
Subject: RE: 3rd &4th St Extension
Michael,
I have two remaining questions related to my original five:
#2- Is the road inside the ROW that is not adjacent to SW8 051007 or SW8 051008 included in the trench design? I do
not see drainage area maps for the trenches outside of SW8 051007 and SW8 051008. We will need those drainage
area maps.
#5—I do not see the finished grade elevations of the driveways demonstrating that they, in fact,drain towards the
houses they serve and do not drain to the road (and therefore the road's BMP)?
IU
I
From: Michael Norton [mailto:[e-mail]]
Sent:Tuesday, March 30, 2010 6:21 PM
To: Michael Norton; Johnson, Kelly
Cc: Don Covil; Lewis,Linda; Larry Sellers
Subject: Re: 3rd &4th St Extension
2

Kelly,
We've taken a look at the plans and offer the following input to your notes/questions. Hope this helps.
The road permit(SW8 980504)was originally permitted for 100% impervious area to account for rainfall amounts in the
"uncovered" right of way in addition to amounts entering these areas from the impervious roadway. This same approach
was used in the revision to make sure the swales(really acting as infiltration basins)would handle runoff from the
impervious areas while also accepting the rainfall falling on top of the swales/basins...a more conservative
approach...These swales do act more as infiltration basins since they are not designed to transport runoff, but rather to
accept/treat it through infiltration, so we think they also satisfy the intent of Alternative Design Option#4.
Questions:
1. Yes-your understanding is correct. We are not aware of any other stormwater plans affecting this area.
2. Yes-that is correct.
3. Yes-that is correct.
4. No-independent treatments.
5. They should comply with their respective design plans/permits&treated as such during construction. It is
intended that the 3rd&4th Street Plan be independent of the other two plans.
Hope this helps. Please contact Don or me if more is needed.
Thanks,
Michael
Original Message
From: Michael Norton
To: Johnson. Kelly
Cc: Don Covil ; Lewis.Linda; Larry Sellers
Sent: Tuesday, March 30, 2010 3:12 PM
Subject: Re: 3rd &4th St Extension
Kelly,
Thanks for the input. Don and I will pull the plans, review your questions below and get back with you soon.
Michael
Michael A. Norton
Compass Pointe Engineering,PA
5041-3 Main Street
Shallotte,NC 28470
910.755.5872 office
910.367-6869 cell
910.755-5875 fax
[e-mail]
www.compasspointeengineering.com
I I ----Original Message
From: Johnson. Kelly
3

To: Michael Norton
Cc: Don Covil ; Lewis.Linda
Sent: Tuesday, March 30, 2010 11:49 AM
Subject: FW: 3rd &4th St Extension
Michael,
I have been trying to work through this all morning,and have cc'd Linda Lewis because I consulted with her to get her
input as she has a lot more experience with this.
When I started looking through the files this morning, I saw that the drainage area maps of the two subdivision
permits(SW8 051007, Resort at Ocean Isle—High Density and SW8 051008, Resort at Ocean Isle—Low Density)do
not include the ROW. The text of the permit does say that all of the BUA inside the property lines as well as all of the
BUA between the property lines and the edge of the pavement(aka,the driveways) are included in the overall
allocated BUA per lot. So the permits do not actually"overlap" in drainage area. I am not sure how we missed that
when we met previously, but it is an important element here. This essentially means that the driveway has to be
considered when considering how big the house can be on each lot, and how big the BMP has to be for SW8 051007
(the high density permit). The road permit(SW8 980504, 3rd and 4th St. Extension)was originally permitted as if it
were 100% impervious,and last summer we added in the bike lanes that had not previously appeared on the plan. I
am not sure why that was done originally, but it may have been because all of the driveway widths and slopes were
unknown at the time and so the project was considered to be built at its full build out potential,as is required.
When SW8 980504 was written last summer the swales had not been built. We decided to permit it anyway,and
require that the PE Cert be submitted soon after construction. In retrospect,that was probably not the best solution
here because the site is still technically in violation because the swales still have not been built. So,we will have to
find a better solution this time. I will have to talk to my supervisor about that. There are also concerns because one
of our inspectors recently inspected SW8 051007 and SW8 051008 in response to a request for a permit transfer, and
found both of them to be out of compliance. So,there are a lot of things that we will have to work through with this
project.
The SW8 980504 mod submitted recently seeks to exclude the driveway BUA inside the ROW from the volume of the
SW8 980504 permitted infiltration swales,and have that BUA be covered only by its respective subdivision permit
(SW8 051007 or SW8 051008). Additionally,the mod seeks to limit the driveway width for lots along the road
permitted under SW8 980504 that are not covered by SW8 051007 or SW8 051008 to 36ft. I have a few questions
about this:
1.) It is my understanding that the lots that will have a maximum of 36ft driveway widths and are NOT inside
either SW8 051007 or SW8 051008 are not within any other State Stormwater permitted area. Is that
correct?
2.) It appears that you intend to not install the infiltration swales originally permitted under SW8 980504 that
were in the ROW for lots NOT included in either SW8 051007 and SW8 051008. Instead,you plan to install an
infiltration trench for each affected driveway and design the trenches to the latest design requirements
(Alternative Design Option#4 on page 16-9 of the manual). Is that correct? (I have not gone through any of
the calculations, but I believe that is your intention.) Is the road inside the ROW that is not adjacent to SW8
051007 or SW8 051008 included in the trench design?
3.) It appears that you intend to continue to permit the infiltration swales originally permitted under SW8
980504 that are in the ROW adjacent to SW8 051007 and SW8 051008 as you had originally designed them,
but you are reducing the volume of the infiltration swale originally permitted by the amount of BUA that will
be covered by driveways inside SW8 051007 and SW8 051008. Is that correct?
4.) There are two drainage areas;one for the infiltration swale and one for the infiltration trench. Is the
treatment system within each drainage area hydraulically connected? (For instance, do all of the trenches
connect within the trench drainage area?)
5.) How does water associated with the driveways within SW8 051007 and SW8 051008 drain away from the
road permit?
4

Thanks,
Kelly
From: Michael Norton [mailto:[e-mail]]
Sent: Wednesday,January 06, 2010 8:57 AM
To: Johnson, Kelly
Cc: Don Cavil
Subject: Re: 3rd &4th St Extension
Kelly,
We'll verify the permits-looks like these are the ones. We have information &plan sheets for them all.
The parties involved are not in disagreement on the matter. We simply discovered during our revision of SW8 980504
for the Town of Ocean Isle that other permits had also been issued to handle the lots/driveways adjacent to this portion
of the roadway. This applies only to a portion of 3rd/4th Street covered under SWE 980504. Unfortunately, we don't
immediately see how the runoff from the roadway can be incorporated into these other permits and don't know if the
only answer is to capture the roadway and all driveways in this area in the Third & Fourth Street permit somehow
(without affecting the design intent of the other permitted plans).
Thanks,
Michael
Original Message
From:Johnson. Kelly
To: Michael Norton
Cc: Don Cavil
Sent:Wednesday, January 06, 2010 7:48 AM
Subject: RE: 3rd &4th St Extension
Michael,
If you have technical questions to resolve,please email me a list of those questions in advance because road projects
are always atypical and I will probably have to consult with others here. But, it sounds like you are saying that the
issue is the"needs of the road"v/s the"needs of the resort"and an inability to find common ground between the
parties involved? If that is the case I am not sure that I will be able to help you,as it is not appropriate for the
Division to get involved in those types of decisions.
Is the following a complete list of the permits involved?:
1.) SW8 051007—"Lots 1-69& Resort Club—The Resort at Ocean Isle Beach"
2.) SW8 051008 "Lots 70-95 —The Resort at Ocean Isle Beach"
3.) SW8 980504—"Third and Fourth Street Extension"
I will see you tomorrow at 2:30 to discuss your list of technical questions unless I hear back from you that you need
to work through any potential "common ground" issues in advance of our meeting. The third permit listed above is
an old file stored at an offsite warehouse,and I will not be able to get that by tomorrow. So, please bring copies of
those plans and any other pertinent file information.
Kelly
From: Michael Norton [mailto:[e-mail]]
Sent:Tuesday,January 05, 2010 5:18 PM
To: Johnson, Kelly
5

Cc: Don Covil
Subject: Re: 3rd &4th St Extension
Kelly,
That is correct. There is overlap in permits. Unfortunately, our meetings with the Town and property representatives
has not provided a clear approach. The"Resort @ Ocean Isle" permit covers drives inside the ROW, as did the
original 3rd &4th Street SW Plan. We're struggling with a suitable alternative for proper treatment of the drives and
the roadway so as not to adversely impact the"Resort"plans.
We can be there©2:30 Thursday(7th) if that works.
Thanks,
MN
Michael A.Norton
Compass Pointe Engineering, PA
5041-3 Main Street
Shallotte,NC 28470
910.755.5872 office
910.367-6869 cell
910.755-5875 fax
[e-mail]
www.compasspointeengineering.com
-----Original Message
From: Johnson. Kelly
To: Michael Norton
Sent: Tuesday, January 05, 2010 1:44 PM
Subject: RE: 3rd &4th St Extension
Michael, .
If I remember correctly,this is related to an area being covered by more than one permit? I assume that you all
have determined what you think is the best resolution the problem and you want to see if DWQ would approve the
approach? What are the sticking points that you need to resolve? If you let me know those in advance I can be
more help to you in the meeting.
I can meet any time in the next two weeks with the exception of the 6th and 13th
KJ
From: Michael Norton [mailto:[e-mail]]
Sent: Monday,January 04, 2010 3:58 PM
To: Johnson, Kelly
Subject: Re: 3rd &4th St Extension
Kelly,
Happy New Year!
Input regarding a time to get together on this one? The Town would like to complete construction activities prior to
end of Spring.
6

Thanks,
Michael
Michael A.Norton
Compass Pointe Engineering, PA
5041-3 Main Street
Shallotte,NC 28470
910.755.5872 office
910.367-6869 cell
910.755-5875 fax
[e-mail]
www.compaspointeengineering.com
Original Message-----
From:Johnson, Kelly
To: Michael Norton
Sent: Thursday, November 19, 2009 9:49 AM
Subject: RE: 3rd &4th St Extension
I got it,and will get back to you as soon as I can. I am in the middle of several compliance issues this week.
From: Michael Norton [mailto:[e-mail]]
Sent:Thursday, November 19, 2009 9:48 AM
To: Michael Norton; Johnson, Kelly
Subject: Re: 3rd &4th St Extension
Kelly,
You may be out. I just wanted to make sure this went through....
Michael
Michael A.Norton
Compass Pointe Engineering, PA
5041-3 Main Street
Shallotte,NC 28470
910.755.5872 office
910.367-6869 cell
910.755-5875 fax
[e-mail]
www.compasspointeengineering.com
Original Message
From: Michael Norton
To:Johnson, Kelly
Sent:Tuesday, November 17, 2009 10:04 AM
Subject: Re: 3rd &4th St Extension
Kelly,
7

Can Don & I arrange a meeting at your place to discuss this one? We met with all parties yesterday and have some
thoughts, but felt it may be best to get NCDENR's input at this point. We have copies of existing plans/permits for
viewing/discussion.
Let me know if this is suitable.
Thanks,
Michael
Michael A.Norton
Compass Pointe Engineering, PA
5041-3 Main Street
Shallotte,NC 28470
910.755.5872 office
910.367-6869 cell
910.755-5875 fax
[e-mail]
www.compasspointeengineering.com
-----Original Message
From: Johnson, Kelly
To: Michael Norton
Sent: Tuesday, November 10, 2009 10:11 AM
Subject: RE: 3rd &4th St Extension
Michael,
Yes, permit areas can not overlap. (The only exception is the offsite permit, but I am not sure that that would
work here.)
KJ
From: Michael Norton [mailto:[e-mail]]
Sent:Tuesday, November 10, 2009 9:25 AM
To: Johnson, Kelly
Subject: Re: 3rd &4th St Extension
That will be fine Kelly. I have scheduled a meeting next Monday afternoon with Ocean Isle representatives and a
representative of the subdivision (Resort©Ocean Isle)to discuss options for resolution.
As I understand it, the area inside the right-of-way needs to be addressed appropriately by ONE of the existing
stormwater plans---not both. If this is not correct, let me know.
Thanks,
Michael
Michael A. Norton
Compass Pointe Engineering, PA
5041-3 Main Street
8

Shallotte,NC 28470
910.755.5872 office
910.367-6869 cell
910.755-5875 fax
[e-mail]
www.compasspointeengineering.com
Original Message
From: Johnson, Kelly
To: Michael Norton
Sent: Tuesday, November 10, 2009 7:53 AM
Subject: FW: 3rd&4th St Extension
Michael,
I got your voicemail yesterday regarding this project. I actually got pulled out to an all-day meeting unexpectedly
yesterday,so I am just now getting to my voicemails. I do not think you all get in until 8,and I have two meetings
this morning, have two projects that I need to get to this afternoon,and I will be out the rest of the week so I
wanted to just drop you a quick note that I did get your message. But, I am having a crazy week. Maybe we can
talk early next week?
Kelly
From: Johnson, Kelly
Sent: Thursday, November 05, 2009 3:09 PM
To: 'Michael Norton'
Subject: RE: 3rd &4th St Extension
Michael,
Did the 10/28 email bounce back to you? I didn't get it. It isn't in my'junk"folder either,so I am not sure what
happened.
KJ
From: Michael Norton [mailto:[e-mail]]
Sent: Thursday, November 05, 2009 2:21 PM
To: Michael Norton; Johnson, Kelly
Cc: Don Covil; Larry Sellers
Subject: Re: 3rd &4th St Extension
Hi Kelly,
Just replying to this email to see if it made it to you. Mr. Sellers could not receive all three attachments at once
due to the file size. Let me know- if you did not get the attachments, I'll send them to you independently.
Thanks,
Michael
9

Michael A. Norton
Compass Pointe Engineering, PA
5041-3 Main Street
Shallotte,NC 28470
910.755.5872 office
910.367-6869 cell
910.755-5875 fax
[e-mail]
www.compasspointeengineering.com
Original Message-----
From: Michael Norton
To: Johnson, Kelly
Cc: Don Covil ; Larry Sellers
Sen :Wednesday, October 28, 2009 1:18 PM
Subject: Fw: 3rd &4th St Extension
Kelly,
As the Town began preparing for construction activities in accordance with this permit modification parties
associated with "The Resort at Ocean Isle Beach"asked the relation between the permit requirements and those
in place for thier subdision. They provided us permit information (see attachments) for the Low Density& High
Density portions of their project along West Third Street.
There seems to be overlap in Right-of-Way coverage/treatment between the permit/plan we modified and these
other plans. Please take a look and provide input if able on how to proceed. We'd be glad to schedule a phone
conference or meeting in your office if needed to review plan details, etc.
Thanks& please call if we can provide more information or clarification.
Michael
Michael A.Norton
Compass Pointe Engineering, PA
5041-3 Main Street
Shallotte,NC 28470
910.755.5872 office
910.367-6869 cell
910.755-5875 fax
[e-mail]
www.compasspointeengineering.com
Original Message---
From: Johnson, Kelly
To: Don Covil
Sent: Monday,August 03, 2009 3:21 PM
Subject: 3rd &4th St Extension
Don,
This permit was signed today. I inserted some language about the designer's certification in the cover letter and
a notice of inspection will also be sent with the permit that essentially re-iterates the need for the DC.
Kelly
10

*** My email has changed to kellv.p.iohnsonccancdenr.xov
K.eLid joliosolA,
Kelly Johnson
Environmental Engineer
Division of Water Quality
127 Cardinal Drive Extension
Wilmington, NC 28405-3845
Office: 910.796.7345
Fax: [phone]
E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and
may be disclosed to third parties.
11

ile
• -•/Re e e
Fioject Received Date: a2
circle one) �
I Project Location:
DteaMle (mo0) A •: info required no), Date recei ed: LI l.•
Symbols for completing form: '✓'=Yes/OK; 'x'= No/Deficient;' ,i,' ' c or'/'
Rule(s) Subject (check all that apply): -
O 1995 Coastal 0 2008 Coastal 0 Phase II 0 Universal
Paperwork:
O Check for$505 (must be no older than 6 months)
0 Application form with correct/original signatures (original plus 1 copy). If Corporation or LLC also:
o Print the info from the NCSOS
o Either, 1.) The applicant is listed on the NCSOS with his/her correct title or, 2.)A notarized letter of
authorization has been provided:
O Supplements (1 original per BMP). BMP t pe(s): POOO 1 \\\1-' ri ( il1,,�,,1
0 O&M with correct/original signatu 'vial per E�/IP except level spreaders/filter and wa s) Wl
0 Deed re cti ns (if outp cel or subd. is g) (origin: -A' r us '
,n
o d plate (sigr,E•J bnd notari , . .1'
IS(
o ro I tion of Covena;its and Re tric ions (signed an notarized)
0 Soils report identifying the SHWT Ada i vAC�
0 Supporting calculi+ions,"ned • (if necessary) //
0 Receiving strear,i clan- ir. uio : sKaiii?stn
• `
o SA: USOS tc;�n m ;,its `he rec th to scale.
o ORW: 5i5 f oet-IIVI_t r Area of environmental Concer and max BUA per rule. \ t )
0 Modifications: 1.) If built: Designer's Cert., 2.) If partially built: Partial Cert., 3.) If not built: No Cert. needed. °\
Development Type (check all that apply)'
O Residential k,, . r. - ial rictit ? (�?.�
0 Subdivision o - l,►_ , AdrictiorTs rrTa ?
Lgr High Density 0 Liw Density 0 Deed restrictions m h?
O Offsite project 0 Redevelr - t 0 Modification C 0564 0 Exempt
0 NCGO2 (bulkhea NO3 (cl::rr d- 0 N ar)Meeffstweje)
Density: i
O BUA calculations in illUl.area , c u. _.1 sidewal , etc.
0 BUA %: , Matches high/low density requirement for rule and receiving stream class.
0 No obvious math er inib
O If High Density: Des }b ielle)ing streh
tS Iliis
Plans, signed and sealed (2 et
We
0 Two sets received 0 Layout (with proposed BUA dimensions)
0 Grading 0 Drainage area map (all HD systems & curb outlet swales)
0 Vicinity map 0 Project Boundaries 0 Legend
0 Wetlands:
o Delineated on plans o "No wetlands onsite" on plans
0 Details:
o Roads o Cul-de-sacs o Curbing o idewalk
o BMPs/ Level spreaders/Filter strips/Curb outlet swales Buildings (Apts or Condos)
Offsite Projects:
O Designer's Certification has been submitted for the Offsite BMP receiving the runoff from the project.
0 Deed restrictions have been recorded and a copy submitted for the Offsite BMP permit.
0 Lot size has not changed from what was approved under the Master Plan.
0 Correct lot number is referenced on the supplement form.
0 Offsite system is in compliance with its permit, if known.
Infiltration Projects:
O Soils report: SHWT, soil type, and expected infiltration rate are provided.
0 DWQ has conducted a site visit? Date:
Wet Ponds: Permanent➢O:A Meets One of the Following:
0 Is located no lower than 6" below the estimated SHWT.
0 Incoming groundwater is quantified and evaluated, AND Storage volume verified, AND Outlet evaluated for free
drainage to the receiving waters under SHWT conditions.
Decision (check one):
O Complete: Return file to admin (Jo Casmer) to log in. (Stamped in received date = BIMS date)
0 Slightly incomplete: E mail consultant, request information to be returned within one business day (24 hours after
request. Info requests on Friday, allow a return on the following business day). If info not returned, issue an
application return letter and give everything to admin. (Add info received date = BIMS date)
0 Substantially incomplete: Issue an application return letter and give everything to admin.

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5041-3 Main Street a %il
z Phone: [phone]
Shallotte, NC 28470 Fax: [phone]
www.CompassPointeEngineering.com Email: [e-mail]
Wednesday,March 17,2010
i
Ms.Kelly Johnson,Environmental Engineer .P:
NCDENR,DWQ
127 Cardinal Drive Extension
Wilmington,North Carolina 28403
Subject: Stormwater Permit No. SW8980504 Modification
3rd and 41h Street Extension
Town of Ocean Isle Beach
Dear Ms.Johnson:
Thank you for you assistance and guidance in our efforts to modify the OIB 3rd & 4thStreet
Extension project to eliminate "overlaps" with The Resort stormwater projects permitted under
DWQ No. SW8 051007 and No. SW8 051008. As an aid to help refresh you about the details of
our past discussions, you may find it helpful to refer to emails between our offices from the latter
part of October 2009 through January 6, 2010. Also,please refer to your meeting notes during our
visit to your office on January 7, 2010.
We have revised the plans and related documents as necessary to eliminate the subject overlap. The
enclosed Stormwater Narrative explains the approach we took. Along with the narrative we have
enclosed:
1. The original and one copy of the Stormwater Management Permit Application Form;
2. Original Infiltration Basin Supplement;
3. Original Infiltration Trench Supplement addressing the individual driveway rock trench
system, said system being identical for each of the 35 proposed systems;
4. Original Infiltration Trench Supplement addressing the cumulative driveway rock trench
systems for the 35 proposed systems;
5. Original Infiltration Basin Operation and Maintenance Agreement;
6. Original Infiltration Trench Operation and Maintenance Agreement;
7. One set of project calculations;
8. Two sets of project plans; and,
9. Check in the amount of$505 to cover the application fee.
It is noted that a new feature of the revised approach to stormwater management entails serving
portions of each of 35 driveways within the 31- & 4th Street right of way with an infiltration trench
system. Each system is identical and is designed to handle the 10 year, 24 hour rainfall with no
overflow at i4 the infiltration capacity, thus providing the basis for waiving the requirement for an
offline bypass and vegetated filter strip. You will note from reviewing the plans that the 35
driveways are along that portion of 3rd& 4th Street that is not contiguous with The Resort projects.
Further, the requirement that the infiltration trenches be constructed per the design details will be
by legal instrument developed and enforced by the Town of Ocean Isle Beach.
LAND PLANNING & SITE DESIGN • WATER • WASTEWATER • STORMWATER • EROSION CONTROi

Ms.Kelly Johnson 2 March 17,2010
Ocean Isle Beach 3`d&4th Street Extension
Also, please note that items 3 and 4 above both address the same project element, the driveway
infiltration trenches. One supplement (item 3) provides information relative to a single trench
system(since they are all identical)and the other supplement(item 4) provides information relative
to the 35 trench systems considered collectively. It may be that you do not need both supplements;
however,we wanted to be sure we were covered relative to this element of the project.
We appreciate your attention to this matter. Please contact us should you have any questions or
comments.
Sincerely, Zj
s. By 10
Donald M. Covil,P.E.
Compass Pointe Engineering,P.A.
Enclosures
cc: Mr.Larry Sellers,Assistant Town Administrator,Town of Ocean Isle Beach

02,
STORMWATER PLAN NARRATIVE .09 A
Ocean Isle Beach 3rd and 4th Street Extension e
DWQ Stormwater Permit No. SW8980504 Modification
Compass Pointe Engineering, PA
March 2010
DWQ issued high density SW Permit Number SW8 980504 Modification for this project on April 30,
1999. The original project included a 20'wide roadway, whereas a 20'wide roadway with 5' bike lanes
on each side was subsequently constructed. The Town of Ocean Isle Beach retained Compass Pointe
Engineering (CPE)to prepare plans and documentation for a renewal (due to a 10-year renewal period)
and a modification (since the paved roadway is 10'wider than that covered by the original permit). CPE
performed the work to reflect the wider roadway and submitted the project to DWQ for approval. DWQ
issued the permit via an approval letter on August 3, 2009.
Subsequent to the August 3 approval, it was discovered by the Town of Ocean Isle Beach that
there existed overlaps of State SW permits between 3rd&4th Street Extension and The Resort projects.
The Resort permits included one of high density(SW8 051007) and one of low density(SW8 051008).
The permits for both projects for The Resort included language stating that the maximum BUA allowed
"includes any built-upon area constructed within the lot property line and that portion of the right-of-way
between the front lot line and the edge of the pavement". The 3'd&4th Street Extension project included
all area within the right-of-way; thus, the overlap exists. In all, 48 lots along 3`d and 4th Street from the
Troy Street intersection to the end of the project(approximate station 34+50)were affected. Of the 48
lots, 5 are currently developed and have existing driveways. The remaining 43 are"future".
The Town, subsequent to discovering the overlap, directed CPE to modify the stormwater
management design documents for 3`d&4th Street Extension to the extent that no overlap would exist
between it and The Resort projects. CPE performed the requested work. The following summarizes the
key elements of the revised approach taken by CPE on behalf of the Town.
1.Both Resort projects are to remain as currently permitted; i.e., the portions of the driveways within
the 3rd&4th Street Extension right-of-way remain with The Resort.
2.Logically, from Item 1, the portions of the driveways within the 3rd&4th Street Extension right-of-
way that are part of The Resort driveways have been removed from 3rd&4th Street Extension.
The 43 affected driveways that are"future"were assigned a width of 36', and the 5 existing
driveways were assigned a width based on actual survey information.
3.There are 35 undeveloped lots along 3`d &4th Street Extension that are not part of The Resort.
These are located from the beginning of the project to the Troy Street intersection. In the
interest of conformity with the adjacent"Resort" lots, these lots were assigned driveway widths
of 36'.
1

4.The wider driveway widths resulted in a reduction in the length of stormwater infiltration swales to
the extent that the swales could no longer serve the entire project. It was thus decided to
design a typical stormwater infiltration trench system for each of the 35 future driveways that
remained with the 3rd and 4th Street Extension project. This meant that the stormwater
infiltration swales would serve the roadway, two existing driveways, and the portion of(future)
Oxford Street that is within the projected 3rd&4th Street right-of-way.
Given the above, the current project is assigned two drainage areas-one for the stormwater
infiltration swales and one for the driveway stormwater infiltration trenches.
The calculations treat the entire area between the right-of-way lines (swales included) as
impervious even though the actual BUA:DA is 81.6 %. This was done because the rainfall would fall
directly on the surface of the infiltration swales as well as on built-upon surfaces. Further, an additional
conservative element was incorporated during design in that the entire 1 %" rainfall was used as the
treatment volume (i.e., the BMP Manual"Simple Method"was not used to reduce the"runoff'amount).
The soils within the swale and infiltration trench areas are sand with an estimated infiltration
capacity in excess of 20 inches/hour as established with the original submittal that was subsequently
permitted by DWQ. The runoff into the swales will be stored "in-place" due to the placement of soil dams
and driveway headwalls.
The calculations demonstrate that the swales are not only adequate to store and infiltrate without
discharge the runoff from the first 1 %" of rainfall but also are adequate to store and infiltrate without
discharge the runoff from the 1-year, 24-hour storm. Further, it is demonstrated that the infiltration swales
will handle the 10-year, 24-hour rainfall without discharge; thus, compliance with alternate design criteria is
established for the waiving of offline bypass and vegetated filter requirements.
This project drains to Eastern Channel, Old Sound Creek which in turn drains to the Atlantic
Intracoastal Waterway (AICW). The stream classification for the AICW at this point is SA.
There are no wetlands within the project boundary.
The Town of Ocean Isle Beach will enact a driveway ordinance to ensure that driveways within the
right-of-way where the infiltration trenches are required will contain language with the following restrictions:
• The maximum obstruction width within the roadside swale to construct the driveway will be 36'
• An infiltration trench system will be constructed as illustrated on the permitted plans.
• No culverts or other means of piping or channeling under the driveway will be constructed.
• No runoff from the driveway outside the roadside right-of-way shall enter the trench infiltration
system.
• Elevation of the top of the headwalls on each side of the driveway within the roadway right-of-
way shall be no lower than the elevation of the roadway center-line less 0.5'.
2

CALCULATIONS AND NOTES
Ocean Isle Beach 3rd and 4th Street Extension
Stormwater Management Plan RenewaUModification
DWQ Permit No. SW 8 980504
orri eit?
41 949'19- 1#61
e3 41e ICE 4,43\:y.of
.':°,�. -0 RECEIVED
MAR 2 2 2010
BY:
Compass Pointe Engineering,PA
Shallotte,NC

0
Ocean Isle Beach 3rd& 4th Street Extension DMC
3/2/2010
BACKGROUND
DWQ issued high density SW Permit Number SW8 980504 Modification for this
project on April 30, 1999. The original project included a 20' wide roadway,whereas a
20' wide roadway with 5' bike lanes on each side was subsequently constructed. The
Town of Ocean Isle Beach retained Compass Pointe Engineering(CPE)to prepare plans
and documentation for a renewal (due to a 10-year renewal period) and a modification
(since the paved roadway is 10' wider than that covered by the original permit). CPE
performed the work to reflect the wider roadway and submitted the project to DWQ for
approval. DWQ issued an approval letter on August 3,2009.
Subsequent to the August 3 approval, it was discovered by the Town of Ocean Isle
Beach that there existed overlaps of State SW permits between 3rd&4th Street Extension
and The Resort projects. The Resort permits included one of high density(SW8 051007)
and one of low density(SW8 051008). The permits for both projects for The Resort
included language stating that the maximum BUA allowed"includes any built-upon area
constructed within the lot property line and that portion of the right-of-way between the
front lot line and the edge of the pavement". The 3rd &4th Street Extension project
included all area within the right-of-way;thus,the overlap exists. In all, 48 lots along 3rd
and 4th Street from the Troy Street intersection to the end of the project (approximate
station 34+50)were affected. Of the 48 lots, 5 are currently developed and have existing
driveways. The remaining 43 are"future".
The Town, subsequent to discovering the overlap, directed CPE to modify the
stormwater management design documents for 3rd& 4th Street Extension to the extent
that no overlap would exist between it and The Resort projects. CPE performed the
requested work, and the following calculations support the request for yet another
modification to the 3rd&4th Street Extension project. The following summarizes the key
elements of the revised approach taken by CPE on behalf of the Town.
1. Both Resort projects are to remain as currently permitted; i.e., the portions of
the driveways within the 3rd&4th Street Extension right-of-way remain with
The Resort.

49
Ocean Isle Beach 3rd&4th Street Extension DMC
3/2/2010
2. Logically, from Item 1,the portions of the driveways within the 3rd&4th Street
Extension right-of-way that are part of The Resort driveways have been
removed from 3rd & 4th Street Extension. The 43 affected driveways that are
"future"were assigned a width of 36', and the 5 existing driveways were
assigned a width based on actual survey information.
3. There are 35 undeveloped lots along 3rd&4th Street Extension that are not part
of The Resort. These are located from the beginning of the project to the Troy
Street intersection. In the interest of conformity with the adjacent"Resort"lots,
these lots were assigned driveway widths of 36'.
4. The wider driveway widths resulted in a reduction in the length of stormwater
infiltration swales to the extent that the swales could no longer serve the entire
project. It was thus decided to design a typical stormwater infiltration trench
system for each driveway. This meant that the stormwater infiltration swales
would serve the roadway,two existing driveways, and the portion of(future)
Oxford Street that is within the projected 3rd&4th Street right-of-way.
Given the above,the current project is assigned two drainage areas -one for the
stormwater infiltration swales and one for the driveway stormwater infiltration trenches.
The calculations demonstrate that each system has more than required capacity to store
and infiltrate the runoff from 1 '/"of rainfall and to infiltrate the peak hour(and all other
hour)rainfall runoff from the 1-year storm.

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Ocean Isle Beach 3rd and 4th Street Extension
SUMMARY of Runoff and Storage Calculations for Areas Served By SW Infiltration Swales
(See enclosed spreadsheets for detailed data.)
North or South Side TOTAL VOLUME BASED TOTAL STORAGE VOLUME EXCESS STORAGE EXCESS STORAGE
Swale? ON 1 1/2"RAINFALL AT (CF) CAPACITY EACH SIDE CAPACITY COMBINED
100%RUNOFF(CF) (CF) (CF)
North 5,936 6,120 184
1,195
South 6,309 7,320 1,011
TEST FOR STORAGE OF POST 1-YEAR,24-HOUR STORM FOR AREAS SERVED BY SW SWALES
GIVEN: 24-Hour Rainfall Depth=3.73 inches Peak Hour Rainfall Depth=1.74
Drainage Area,A =2.27 acres BUA=1.78 acres BUA/DA=0.78 Infiltration Rate=20"I hour
Adjust Peak Hour Depth to Reflect all rainfall falling on SW Swales..... (1.74'Y hour) / (1 -.78) = 7.9"/hour
TIME TO INFILTRATE 7.9" = 7.9" / (20"!HOUR)= 0.40 Hours
0.40 hr is less than 1 (peak rainfall)hour.>>> OK
NOTE: See following page for DWQ"typical"method for calculating drawdown time for 1 1/2"rainfall and 1-Year,24-Hour rainfall.
SPECIAL NOTE: The total storage volume from this table totals 12,245 CF whereas the"Volume provided"on the Infiltration
Basin Supplement(IBS) is stated to be 12,379 CF. The reason for this small difference lies primarilly in the fact that the volume
reported in the IBS incorporates a small amount of BUA contingency(see Built-Upon Area Data Table),whereas the storage
volume presented in this table is taken directly from the spreadsheets addressing the numerous individual swale segments.
Said spreadsheets do not incorporate any BUA contingency.
Compass Pointe Engineering,PA DMC
Ocean Isle Beach,NC 3/2/10

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Precipitation Frequency Data Server Page 1 of 1
POINT PRECIPITATION e, , N
!:f FREQUENCY ESTIMATES t
FROM NOAA ATLAS 14
NORTH CAROLINA 33.8892 N 78.4406 W 0 feet
from"Precipitation-Frequency Atlas of the United States'NOAA Atlas 14,Volume 2,Version 3
GM.Bonnie,D.Martin,B.Lin,T.Parzybok,M.Yektn,and D.Riley
NOAA,National Weather Service,Silver Spring,Maryland,2004
Extracted:Fri Mar 27 2009
-Confidence Limits .Seasonality•`:1. Location il�iaps' ;� 04 elf tn data Maps] Docs Return to, ate Map , •
Precipitation Frequency Estimates(inches)
ARI* 5 l -in 1430 600 10 20 30 I 45 60
(years) I 3 hr 6 hr hr 24 hr 48 hr 4 da
min min min min min J2 y 7 day day day day h d day
1 0.51 0.81 1.02 1.39 pm 2.07 12.23 ®®gas 4.36 4.86 MI 6.29 8.43 10.45 13.02 15.66
2 0.60 0.96 ®1.67 2.10 ®2.71 3.33 3.91 4.53 5.27 5.87 6.73 7.53 10.04 12.41 15.39 18.45
5 0.70 ® 1.41 2.01 ®®3.42 14.22 4.98 5.86 16.76 7.43 8.45 9.31 12.21 14.86 18.17 21.54
- 10 0.78 nap 2.29 2.98 gga 4.07 5.03 5.97 7.00 8.03 9.86 10.77 13.99 16.80 20.38 23.95
25 0.88 1.40 ElaTiileallEal 4.97 6.17 [7.38 8.73 9.93 10.67 11.90 12.85 16.46 19.46 23.38 27.14
50 0.96 ®1.93 2.91 3.94 5.19 ®Egi 8.65 10.24 ®® 13.60 gm 18.48 Mal®29.61
100 1.04 1.65 2.08 3.19 4.39 5.89 6.63 8.28 10.03 11.93 13.40 14.10 17211 16.41 20.60[23.74 28.12 32.05
r 200 ®1.76 ®3.46 4.86 6.65 En9.50 11.59 EMI EOM 16.07 IECII Eal EMI 25.97 30.55 34.49
500 ®1.92 MI 3.83 5.50 um 8.97 11.31 13.92 16.76 BEI 19.05 20.28 21.19 25.97129.03 33.85 MO
1000 1.29 2.04 12.56 ap 6.05 8.69 10.21 12.93 16.03 19.32 ®21.61 22.67 ®28.52 31.44[36.43 40.18
•These predplation frequency estimates are based one trarltd duration sedee.ARI is the Average Recurrence Interval.
Please refer to NO/A./Mae 14 Document for more Information.NOTE Formatting forces estimates near zero to appear as zero.
• *Upper bound of the 90%confidence interval • - ••
Precipitation Frequency Estimates(inches) •
AR1** 5 10 15 30 60 120 3 6 12 24 48 4 7 10 20 30 45 60
.. (years) min min ,min. min min min hr hr hr hr hr day day day day day day day •
1'"'•• 0:55 0:88 1.10 1.50 1E3 2.26 2.46 3.03 3.59 mui mg 5.30 6.04• 6.77 9.01 11.14•pp 16.54 . . •
' • 2 •10.65 1:04 muEip®2.99 3.69 4.36 5.02 5.83 6.41 7.29 8.12 10.76 1123 1i6.33 19.50 '
.5 0.75 ®®®Em 3.46 ®4.66 5.56 6.48 7.47 01311 9.15 10.04 13.07 15.82 19.28 22.74 •
10 0.84.®® n .08 gps 6.65 Egai mg 9.54 10.69 11.62 14.95 17.90 21.63 alp ' ."
25 0.95 ®1.92 miggi34.92 EglEl 6.79 8.20 9.63 10.96 11.64 12.90 13.86 17.61 20.75 C131128.67 •50 EDE 1.64 2.08 gip op I=D 6.35 7.90 9.59 11.29 1279 13.45 14.75 15.74 19.80 23.05 27.36 Mal
100 mg®2.24 MOi' 16.41 7.29 9.10 ® 13.18 14.85 IFEI 16.78 17.75 22.13 25.41 29.96 33.97
200 1.20 1.90 .40 n gm®an 10.43 miEil® : 17.67 18.99 19.95 24.62 gig 32.66 36.64
500 ®2.07 2.60 4.14 5.95 mj 9.86 12.44 15.42 18.62 20.73 21.08 ®21.16 28.20 ®36.39 140.26
1000 1.40 12.21 ®4.49 6.56 9.48 ®nap®EgEa23.87 24.08 25.06 25.89 ®34.10 39.35 143.09
•The upper bound of the confidence Interval at%%confidence level le the value which 5%of the simulated omegas values for a given frequency are greater than.
"These predpllegon frequency estimates ere based an a petal duration series.ARI le the Average Recurrence Interval.
Please refer to NOAA Mae 14 Document for more idannagon.NOTE Fctmall ng prevents estimates near zero to appear as zero.
*Lower bound of the 90%confidence interval
Precipitation Frequency Estimates(inches)
ARP** 5 10 15 30 60 120 3 6 12 24 48 4 7 10 20 30 45 60
(years) min min min min min min hr hr hr hr hr day day day day day day day
1 1 0.47 0.75 0.94 1.29 1.61 1.91 2.05 2.51 12.92 3.41 3.99 mi 5.17 5.86 17.90 9.84 pm mg
2 0.56 0.90 mg mg 1.95 ®2.48 3.05 gici 14.14 aEgi 5.41 6.24 7.01 9.41 11.68 14.52 17.46
I. 5 0.65 1.03 ® 1.86 pi 2.91 ®3.85 4.50 ®6.17 6.83 n 8.64 11.43 13.96 ®20.35
10 0.72 ® 1.46 ®®gai 3.70 4.56 m36.36 7.30 8.02 9.10 9.98 13.06 ® 19.18 Eam
r 25 0.81 1.29 1.63 mg®aig 4.50 5.56 6.59 7.86 n 9.71 10.92 IBM 15.30 11313121.93
50 0.88 1.40 ®2.67 3.61 4.7015.19 6.43 7.67 9.14 10.33 11.12 12.40 13.35 17.09[20.07 24.05 27.74
100-n 1.50 1.89 2:90 en®5.92 7 5 1MS 10.54 f 11.:84 12.62 13:96 14.92 18.92' 21 98 26713 29:90
200 1.00 1.59 2.01 ®4.39 5.95 6.71 8.35 10.07 12.07 13.491 14.24 15.60 16.55 20.81 23.90 Egli 32.02
500 1.08 1T7T,2.16 3.43 4.93 6�8TI ED I9.80 111.92 114.33 115.90 16.61 17.91 18.84 23.39 126.45131.04 cm
111000 ®mi 2.27 3.68 ®7.63 am 11.08 ® 16.24 17.93 Mal 19.79 20.67 25.41 28.41 33.16 36.84
•The lower bound of the confidence Interval 0190%coradence level is the value which 5%of the simulated quango valves for a given frequency are leas than.
"These precipitation frequency estimates are based one partial duration maims series,ARI is the Average Resurenm Interval.
Please refer to NOM Atlas 14 Document for more hdormeton NOTE ForrralWg prevents estimates near zero to appear as zero.
Text version of tables f
http://hdsc.nws.noaa.gov/cgi-bin/hdsc/buildout.perl?type=pf&units=us&series=pd&statcna... 3/27/2009

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OCEAN ISLE BEACH 3RD&4TH STREET DRIVEWAYS SERVED BY INFILTRATION TRENCHES I
ROUTING TABLE FOR 10 YEAR PEAK RAINFALL OVER AREA SERVED BY THE INFILTRATION BASIN
Potential Time Segment
Time from Start 10 Year Peak 10 Year Peak Runoff Volume Volume Not Incremental Accumulated
for from Surface Area Infiltration Volume©10"/hour
of Peak Hour Rainfall Rate Rainfall Depth
Over Surface Area of 96 SF Infiltrated Water Depth Water Depth
(min.) (in./hr) Time Segment(in.) of 540 SF(CF) (CF) (CF) Change(Ft.) Change(Ft.)
0 2.98 0.298 0 8 0 0 0
6 2.98 0.298 13 8 5 0.06 0.06
12 2.98 0.298 13 8 5 0.06 0.11
18 2.98 0.298 13 8 5 0.06 0.17
24 2.98 0.298 13 8 5 0.06 0.23
30 2.98 0.298 13 8 5 0.06 0.28
36 2.98 0.298 13 8 5 0.06 0.34
42 2.98 0.298 13 8 5 0.06 0.39
48 2.98 0.298 13 8 5 0.06 0.45
54 2.98 0.298 13 8 5 0.06 0.51
60 2.98 0.298 13 8 5 0.06 0.56
66 0.76 0.076 3 8 -5 -0.05 0.52
72 0.76 0.076 3 8 -5 -0.05 0.47
78 0.76 0.076 3 8 -5 -0.05 0.42
84 0.76 0.076 3 8 -5 -0.05 0.37
90 0.76 0.076 3 8 -5 -0.05 0.33
96 0.76 0.076 3 8 -5 -0.05 0.28
102 0.76 0.076 3 8 -5 -0.05 0.23
108 0.76 0.076 3 8 -5 -0.05 0.18
114 0.76 0.076 3 8 -5 -0.05 0.13
120 0.76 0.076 3 8 -5 -0.05 0.09
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