PINE KNOLL SHORES_COMPLETE FILE - HISTORICAL_20130319

-STORMWATER DIVISION CODING SHEET
Municipalities NOT MS4
PERMIT NO.
NCS0000_ �� f �,srt.6
DOC TYPE
❑ COMPLETE FILE - HISTORICAL
MOST RECENT
DATE
❑ 3y [ c]
YYYYM M D D

T t o kN o I-C- -754 D.lze -

���'I
1
!
� �
f
I
_
.._,
._
r,
.M
_.
�
4
I i �
I I
I
}' � �
�,
� s
�.,.
i.w��
��
'
_
k�
I
,
� ��
i
I
I�r'
±�
� `I
f
i
.,
;
�
rJ
�
I
I
~
I
}
1
1
YY
I
I
'
I
_z
e'�
4
I .•
1
"3
rl
1
1 I
I
I�
I
� �
�
. �� I
.1
'
;
�
�
i
j
I
I
� _
I �
`; -
�� ��r��ll
�
i � �
�
1
�
�
�
;
�
f
�'�
I
I
�
I

Diuguid, Bill
Subject: RE: Pine Knoll Shores Impervious Ordinance
Scott:
We are pleased that Pine Knoll Shores has decided to adopt stormwater management requirements
for new development that will address the development that disturbs less than an acre and
therefore, for the most part, is not regulated by the State's coastal stormwater rules.
Unless the Town of Pine Knoll Shores seeks delegation of the coastal rules from the State,
when a proposed new development reaches the one acre disturbance threshold, they will still
be required to get a State Stormwater Permit. We would like your proposed new rules to
mirror the State's Stormwater Management rules administrative procedures and design standards
that we follow in implementing the Coastal Stormwater Rules. So that the town's new
regulations and the State's rules can be easily implemented together when required.
The State's Coastal Stormwater rules are found in the North Carolina Administrative Code 15A
92H .1005, and they refer to other stormwater standards found in .1003 and .1008 among other
standards.
The present coastal stormwater rules are administered by the two DENR DWQ regional offices in
Wilmington (for Carteret County) and Washington, covering the 20 coastal counties.
Stormwater Permits are required generally for all development projects that require a
Sedimentation and Erosion control permit and a CAMA Major permit or basically projects that
disturb one acre or more.
Development projects that meet this criteria will still need to apply for a state stormwater
permit from the Wilmington DWQ regional office. Unless, Pine Knoll Shores (PKS) is seeking
delegation of the coastal stormwater program from the State, in which case, PKS would have to
adopt a town ordinance incorporating all of the coastal stormwater rules and program
procedures that they would then administer.
If the residential development that you are proposing to regulate falls below the above
thresholds than such development would not be subject to the State's permit requirements. So
it's more protective of the coastal waters for Pine Knoll Shores to adopt standards to deal
with that type of development. This is not unusual. Kure Beach's stormwater ordinance, for
example, requires lots of 5,000 square feet and up to control and treat their stormwater
runoff.
I have attached a link to our model State Post -Construction Stormwater Ordinance which has
all of the State recommended provisions that we think should be in such an ordinance, found
here: http://portal.ncdenr.org/web/wq/npdessw/ms4resources. I will refer to sections of this
model ordinance in my comments on the draft Pine Knoll Shores ordinance.
We require that a 'qualified professional' prepare the stormwater management plan for a site.
This generally means a PE registered in North Carolina. See model ordinance language at
Section 203 (B).
We note that you want a new residential development to treat the balance of runoff from
impervious surfaces from the two inch storm in excess of 12% of the lot. This is logical
from the standpoint that if a lot is 12% impervious or less, they are not required to do any
stormwater control or treatment. However, the State's standard is that if the new
development site is more than 12% impervious they are required to treat all of the impervious
surface runoff (not just the excess over 12% impervious) from the one and one half inch
storm. The net effect of this difference is that the State standard that is triggered with
one acre of disturbance is several times the treatment requirement of the proposed local
I

+�• h
ordinance. At best, this will be confusing to the development community. See Section 303
(A) of the model ordinance.
In addition, much of Pine Knoll Shores is within 1/2 mile and draining to SA waters, so the
additional requirement of controlling and treating the difference in stormwater runoff from
the pre- and post -development site conditions for, at a minimum, the 1-year, 24 hour storm.
See Section 303 (A) as well.
Other requirements for detention drawdown time and treatment of 85% Total Suspended Solids
also apply at this one acre threshold.
Granted, most of these requirements would rarely apply to a residential development unless
several structures are being built or planned to be built in a common plan of development
which cumulatively will disturb one acre of development.
A simpler way of doing what you want to do, would be to apply the State's coastal rules to
all new development in Pine Knoll, essentially lowering the State Coastal Rules one acre
threshold.
-----Original Message -----
From: Scott Sherrill [mailto:[e-mail]]
Sent: Tuesday, March 19, 2013 11:32 AM
To: Gregson, Jim
Cc: Diuguid, Bill
Subject: Pine Knoll Shores Impervious Ordinance
Good morning, Jim and Bill,
Our Town is proposing an ordinance, which is right now in the subcommittee phase, but I
wanted to make sure that the proposed ordinance would not run afoul of the State Stormwater
Regulations, and was wondering if you might review. Please see the attached draft.
Thank you for your help,
Scott Sherrill, Town Clerk
Town of Pine Knoll Shores
100 Municipal Circle
Pine Knoll Shores, NC 28512
252-247-4353, ext 11
[e-mail]
z

3I1 �I 2 d f3
7 FjL v
Sec. 74-289. Maximum lot coverage. X
Impervious coverage, including, but not limited to roofs, driveways, paved walkways and paved
patios, shall not�ee. ercent of the total land area for each lot within residential property
districts Z-];�2-2, R-3 and R-4 nless the lot owner provides for the lot a stormwater retention
system.
A stormwater retention system must be constructed to capture and retain on the lot the first two
inches of rainfall for any development or redevelopment in excess of 12 percent impervious
cover. An engineer may be required to design the system. The constructed stormwater retention
system must meet the following criteria- //}}
5°
a. The system must provide for the collection and retention on the lot of' a volume of
water equal to 2 inches multiplied by the square footage of impervious cover in excess of'
12% of the lot; ��A.� -��C �'�' r ,,� 1 l i Q rF \// a us
b. Water discharged by downspouts and impervious driveways must be taken into
consideration when water is to be retained on the residential property and every effort
should be made to redirect that discharge into a natural area;
c. The retained water may not be discharged off the lot and must be disbursed by
absorption into the ground or evaporation;
d. The stormwater retention system must be constructed as designed;
s jj KK v z 03
e. If an engineer is necessary, the engineer designing and certifying the stormwater
�--� retention system must certify to the town that the system has been constructed as
designed; and (�,,„ I ; -C-+��, -,(Coj�,es,u-;�j,.0
f. The system must be perpetually maintained by the various owners of the lot during
their time of ownership. ir-o GarWalcQ( y, A;,-fa,✓�.c.
Even when the lot owner provides the stormwater retention system constructed as described,
impervious coverage shall not exceed 30 percent of the lot.
2.; -�,
For the area designated as the flood prone area in Section 30-26 (i) and any other lot in
residential property districts R-1, R-2, R-3, and R-4 with a seasonal high water table of 24 inches
or less to grade, impervious coverage shall not exceed 25 percent of the lot even when the lot
owner provides a stormwater retention system constructed as described above.
Notwithstanding the provisions of this section, should impervious coverage on any lot as of
(insert ordinance date), exceed the limits established herein, the following shall apply. In the
event of a casualty loss (i.e., unintentional loss) that results in a decline of less than 50% of the
tax value of the structure, such lot and the structures thereon shall be deemed conforming for all
purposes, including maintenance and reconstruction of improvements in the event of damage, as
long as the amount of impervious surface is not increased. In the event demolition, damage, or

destruction to structures with impervious coverage exceeding the limits above results from the
intentional act of the property owner or his agents or a casualty loss that results in a decline of
more than 50% of the tax value of the structure, reconstruction shall be subject to this section and
to the provisions relating to nonconformity set forth in article VII.
In the event of any casualty loss or intentional act of the property owner that results in
reconstruction, a stormwater retention system may be required in accordance with the provisions
of this section.
Natural terrain shall be maintained to the extent possible with minimum disturbance to maritime
forest and shrubs and impact to adjacent properties.
Sec. 74-315 Maximum Lot Coverage
Impervious coverage, including, but not limited to roofs, driveways, paved walkways and paved
patios, shall not exceed 12 percent of the total land area for each parcel within recreational
property districts 1, 2, and 3 unless the lot owner provides for the lot a stormwater retention
system.
A stormwater retention system must be constructed to capture and retain on the lot the first two
inches of rainfall for any development or redevelopment in excess of 12 percent impervious
cover. An engineer may be required to design the system. The constructed stormwater retention
system must meet the following criteria:
a. The system must provide for the collection and retention on the lot of a volume of
water equal to 2 inches multiplied by the square footage of impervious cover in excess of
12% of the lot;
b. Water discharged by downspouts and impervious driveways must be taken into
consideration when water is to be retained on the residential property and every effort
should be made to redirect that discharge into a natural area;
c. ']'he retained water may not be discharged off the lot and must be disbursed by
absorption into the ground or evaporation;
d. The stormwater retention system must be constructed as designed;
e. If an engineer is necessary, the engineer designing and certifying the stormwater
retention system must certify to the town that the system has been constructed as
designed; and
f: The system must be perpetually maintained by the various owners of the lot during
their time of ownership.
1-ven when the parcel owner provides the stormwater retention system constructed as described
above, impervious coverage shall not exceed 12 percent of the parcel for recreational property
district 1, 30 percent of the parcel for recreational property district 2, 25 percent of the parcel for

recreational district 3, or 10 percent of the parcel for recreational district 3 when the parcel size
exceeds 10 acres.
Notwithstanding the provisions of this section, should impervious coverage on any lot as of
(insert ordinance date), exceed the limits established herein, the following shall apply. In the
event of a casualty loss (i.e., unintentional loss) that results in a decline of less than 50% of the
tax value of the structure, such lot and the structures thereon shall be deemed conforming for all
purposes, including maintenance and reconstruction of improvements in the event of damage, as
long as the amount of impervious surface is not increased. In the event demolition, damage, or
destruction to structures with impervious coverage exceeding the limits above results from the
intentional act ofthe property owner or his agents or a casualty loss that results in a decline of
more than 50% of the tax value of the structure, reconstruction shall be subject to this section and
to the provisions relating to nonconformity set forth in article VI1.
In the event of any casualty loss or intentional act of the property owner that results in
reconstruction, a stormwater retention system may be required in accordance with the provisions
of this section.
Natural terrain shall be maintained to the extent possible with minimum disturbance to maritime
forest and shrubs and impact to adjacent properties.
Sec. 74-334 Maximum Lot Coverage
Impervious coverage, including, but not limited to roofs, driveways, paved walkways and paved
patios, shall not exceed 12 percent of the total land area for each parcel within the multifamily,
commercial, office professional, municipal service, and institutional zoning districts unless the
lot owner provides for the lot a stormwater retention system.
A stormwater retention system must be constructed to capture and retain on the lot the first two
inches of rainfall for any development or redevelopment in excess of 12 percent impervious
cover. An engineer must design the stormwater retention system. The constructed stormwater
retention system must meet the following criteria:
a. The system must provide for the collection and retention on the lot of a volume of
water equal to 2 inches multiplied by the square footage of impervious cover in excess of
12% of the lot;
b. Water discharged by downspouts and impervious driveways must be taken into
consideration when water is to be retained on the residential property and every effort
should be made to redirect that discharge into a natural area;
c. The retained water may not be discharged off the lot and must be disbursed by
absorption into the ground or evaporation;
d. The stormwater retention system must be constructed as designed;

e. If an engineer is necessary, the engineer designing and certifying the stormwater
retention system must certify to the town that the system has been constructed as
designed; and
f. The system must be perpetually maintaine by the various owners of the lot during
their time of ownership.
Even when the parcel owner provides the stormwat r retention system constructed as described,
impervious coverage shall not exceed 50 percent of the parcel. Single-family residences
constructed in multi-family-2 and institutional zonin ,) districts shall be subject to the im ervious
surface requirements described in Section 74-289.
Notwithstanding the provisions of this section, should impervious coverage on any lot as of
(insert ordinance date), exceed the limits established herein, the following shall apply. In the
event of a casualty loss (i.e., unintentional loss) that results in a decline of less than 50% of the
tax value of the structure, such lot and the structures thereon shall be deemed conforming for all
purposes, including maintenance and reconstruction of improvements in the event of damage, as
long as the amount of impervious surface is not increased. In the event dernolition, damage, or
destruction to structures with impervious coverage exceeding the limits above results from the
intentional act of the property owner or his agents or a casualty loss that results in a decline of
more than 50% of the tax value of the structure, reconstruction shall be subject to this section and
to the provisions relating to nonconformity set forth in article VI1.
In the event of any casualty -loss or intentional act of the property owner that results in
reconstruction, a stonnwater retention system may be required in accordance with the provisions
of this section.
Natural terrain shall be maintained to the extent possible with minimum disturbance to maritime
forest and shrubs and impact to adjacent properties.