Drainage Master Plan-1989

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Division of Coastal Management
This document should be used in conjunction with
the 1991 Holly Ridge Land Use Plan Amendment.
HENRY VON OESEN AND ASSOCIATES
CONSULTING ENGINEERS AND PLANNERS

' DRAINAGE MASTER PLAN
TOWN OF HOLLY RIDGE, NORTH CAROLINA
OCTOBER, 1988
' REVISED MARCH, 1989
ADOPTED JULY 11, 1989
' Prepared For: Board of Commissioners,
Planning Board and Citizens of
Holly Ridge, North Carolina
' Prepared By: HENRY VON OESEN AND ASSOCIATES, INC.
Consulting Engineers & Planners
805 North Third Street ** P. O. Drawer 2087
t Wilmington, North Carolina 28402
[phone]
The preparation of this report and associated maps was financed
in part through a grant provided by the North Carolina Coastal.
' Management Program, through funds provided the Coastal Zone
Management Act of 1972, as amended, which is administered by the
Office of Ocean and Coastal Resource Management, National Oceanic
' and Atmospheric Administration.
3271 (040489)

�rJ
F
Table of Contents
SECTION 1: INIRODUCTION AND SODPE OF WORK
1.1 Introduction...........................................1-1
1.2 Scope of Work.........................................1-1
1.3 Background Infornnation.................................1-3
1.4 'Topographic Maps.......................................1-3
1.5 Public Participation...................................1-4
' SECTION 2: EXISTING CONDITIONS
2.1 Physical Setting.......................................2-1
' 2.2 Developrent and Land Use Patterns ...................... 2-1
2.3 Topography, Surface Waters, Soils and Areas of
Enviromental Concern (AEC's) .........................2-3
n
2.3.1 Topography and Surface Waters...................2-3
2.3.2 Soils...........................................2-4
2.3.3 Areas of Environmental Concern ..................2-4
Map 2..3.2.1: General Soils Maps
Holly Ridge, NC
Table 2.3.2.1: Estimated Soils Properties
Significant to Engineering
2.4 Climate/Rainfall Intensity and Duration................2-5
2.4.1 Climatic Summary.................................2-5
2.4.2 Rainfall Intensity/Duration.....................2-5
Table 2.4.2.1: Inches of Rainfall for
Various Recurrence and
Accumulation Times for
Southern Coastal Area
of North Carolina
2.5 Existing State Coastal Area Stornwater
Control Regulations....................................2-5
2.6 Applicability of Existing Stonmvater Control
Regulations to Holly Ridge, NC ................. ........2-8
Figure 2.6.1: Stornvater System Design

Table of Contents, Continued
SECTION 3: DRAINAGE STUDY METHODS
3.1 General.. ..........................................3-1
3.2 Run -Off Calculations
...................................3-1
SECTION 4: IDENTIFICATION OF EXISTING MAJOR DRAINAGE
FRCBLEM AREAS
AND THEIR POSSIBLE SCLUTIONS
4.1 Priorization of
Projects Based on Severity of Need ..... 4-1
4.2 Problem Areas,
Possible Solutions) and Estin-ated
Cost...................................................4-2
Table 4.2.1: Cost Sutmary, Drainage
Tnmprovements Proj ect
Map 4.2.1:
Proposed Drainage Improvements
Highvay 17 and Highaay 50
Map 4.2.2:•
Proposed Drainage Improvements
Camp Davis Road and Holly Street
Map 4.2.3:
Proposed Drainage improvements
Camp Davis Road and Lloyd Street
Map 4.2.4:
Proposed Drainage Improvements
Lloyd Street
Map 4.2.5:
Proposed Drainage Improvements
Jones Street
Map 4.2.6:
Proposed Drainage Improvements
Highway 50
Map 4.2.7:
Proposed Drainage Improvements
Northeast Area of TOm
Map 4.2.8:
Proposed Drainage Improvements
Borroughs Road Area
Map 4.2.9:
Proposed Drainage Improvements
Camp Davis/Beam Street Area
4.3 Maintenance of
Drainage Systems ........................4-3

Table ,of Contents, Continued
SECTION 5: PROTECT IMPLEMENTATION
5.1 General................................................5-1
5.2 Project Scheduling ........... ............ ............ ..5-1
5.3 Project Funding........................................5-1
Table 5.3.1: Recam-ended Project Funding
Alternatives
SECTION 6: LOCAL RB3ULA10RY CONTROL STRATEGIES
6.1 General.... o ................. o ................... ---6-1
6.2 Strategy for Storav ester Control ........................6-1
6.3 Draft Stornvater Control Ordinance .....................6-2
SECTION 7: SUnVMRY, CONCLUSIONS AND REOa4E1,IDATIONS
7.1 Summary and Conclusions. ......
7.2 Recam-endations........................................7-3
APPENDICES
A TOPOGRAPHIC MAPS OF HOLLY RIDGE AREA
B CLIMATIC SU44ARY
C EXISTING COASTAL AREA STOP WATER CONTROL REIz LATIONS
D MODEL STORMaTER CONTROL ORDINANCE FOR HOLLY RIDGE,
NOR H CAROLINA.

' DRAINAGE MASTER PLAN
TOWN OF HOLLY RIDGE, NORTH CAROLINA
' SECTION 1: INTRODUCTION AND SCOPE OF WORK
1.1 Introduction
' This study was commissioned by the Board of Commissioners of
the Town of Holly Ridge, North Carolina, in February, 1988 to
' provide a comprehensive, rational drainage master plan for
' programming needed future improvements to the Town's existing
drainage systems and for the orderly development of new drainage
systems in areas which are currently undeveloped or not fully
developed. The study and report to follow centers on the area
within the existing Town limits of Holly Ridge, and
a proposed
'
annexation area to the south and east. The study covers
both
piped systems and open "natural" systems including
canals and
'
creeks.
This study was conducted by the firm of Henry von Oesen and
Associates, Inc., Consulting Engineers and Planners,
Wilmington,
'
NC with administrative guidance and grant assistance
provided by
the N.C. Division of Coastal Management.
1.2 Scope
of Work
The study consisted of the
following major work elements:
'
• The
production of a set
of topographic contour maps of the
Town
and environs to meet map requirements of 1'- 200 feet
and
contour intervals of
5 feet. The topographic base map
1 - 1

from USGS sheets using
'
sheets were produced quadrangle
reprographic techniques (see Section 1.4 for details).
'
• Locate and map all existing drainage facilities including
storm drains, creeks, catch basins, culverts, open ditches,
and drop inlets.
• Record information on existing pipe sizes, pipe types, and
'
invert elevations (tied to existing bench marks) on the
,
contour maps.
• Locate major drainage boundaries and drainage basin
'
sub -areas on the contour maps.
• Conduct interviews and discussions with Town personnel,
'
citizens and other knowledgeable individuals concerning the
'
nature of the existing drainage system and the nature and
extent of existing problem areas.
,
• Identify existing and future potential problem areas on the
contour maps.
'
• Prepare preliminary designs of drainage systems for each of
'
the existing problem areas.
• Determine preliminary estimated costs associated with the
'
proposed drainage improvements and assign each project a
priority based on needs predicated on a set of accepted
'
criteria.
• Develop a project financial plan and explore sources of
potential grant assistance, if any.
,
• Present the draft master plan to the local government and
the N. C. Division of Coastal Management for review and
'
approval.
1 2 1

1.3 Background Information
The Town of Holly Ridge has experienced drainage problems for
' many years. Beginning in 1974, the Town has taken steps to
identify and correct the problems. In 1979, the 201 Facilities
' Planning Report identified several cross connections between the
sanitary sewer system and storm drainage systems in the Camp
' Davis area. Many of these were subsequently corrected by a sewer
' system rehabilitation project completed in 1986.
In January, 1988 the State Division of Environmental
Management promulgated Stormwater Control Regulations. In an
effort to comply with these new regulations on a municipal level,
' the Town authorized. this study. In July, 1988 the Town was
' inundated by heavy rainfall* exceeding 6 inches in 8 hours which
caused serious flooding in several areas of Town. This condition
' assisted the Town and its consultants to identify the more
serious drainage problems which are addressed hereinafter.
1.4 Topographic Maps
A series of six (6) topographic maps of the Town and environs
twere developed by modern reprographic techniques. A base street
map of the Town was enlarged and superimposed over enlarged U.S.
' Geological Survey quadrangle maps at a final scale of 1" = 200
' feet and contour intervals of 5 feet. The USGS quadrangle base
maps used were the Holly Ridge and Maple Hill 7.5 minute quad
sheets. New clean mylar base maps were subsequently produced by
I
1 - 3

reprographic techniques and used as the basis for the development
of this plan.
The major drainage structures and components were then
located in the field by standard ground survey techniques and
then were placed on the mylar base maps. However, minor driveway
drain pipes, which were located in the field, were not placed on
the drawings for the sake of clarity.
A complete set of copies of these topographic maps are
appended to this report (see Appendix A).
1.5 Public Participation
As required by Coastal Management Regulations, public
participation was encouraged in the development of this plan. To
this end the results of the topographic mapping' of the Town and
the tentative identification of problem areas was presented at a
regularly scheduled meeting of the Town Board held on July 12,
1988 at the Town Hall. The meeting was well attended by the
general public and ample opportunity was provided to answer
citizens' concerns and questions. A complete summary of this
meeting is available at Holly Ridge Town Hall.
Also, the results of the study report including
identification of the problem areas, their proposed solutions and
estimated costs were presented to the Town Board and interested
citizens at a special called meeting of the Board held on
September 27, 1988. A summary of this meeting is available at
the Town Hall. Additional opportunities for public input and
C
1 - 4

citizen involvement will be afforded during the plan
implementation phase of this project (see Section 5 below).
F
' 1 - 5

SECTION 2: EXISTING CONDITIONS
2.1 Physical Setting
The Town of Holly Ridge is located on the southern tip of
Onslow County in North Carolina's coastal plain. While only a
few miles from the Atlantic Ocean, Holly Ridge is situated in a
largely rural area surrounded by farmland and undeveloped
woodlands. The once developed but now mostly vacant land of Camp
Davis lies just to the northwest of the Town limits. The Town
itself has a land area of approximately 860 acres. The adjacent
area of proposed annexation included in this study consists of
about 500 acres. Holly Ridge sits on a slight hill, where the
average land elevation is about 50 - 60 feet above sea level.
The Town Is built primarily upon sandy
soils, though
some organic
deposits are
found near stream beds.
Two
highways
pass through
Holly Ridge;
US 17 and State Highway
50.
US 17 runs generally
north -south
over the entire coastal plain
of North
Carolina and
Highway 50 is
a link to the west and,
to
the east
is a direct
I
route to the beaches of Topsail Island.
' 2.2 Development and Land Use Patterns
The Town of Holly Ridge
was incorporated during World War II
when Camp
Davis, a military
air base just northwest of Town was
active.
Camp Davis has since been dismantled and the Holly Ridge
community
today is largely
rural and residential. Commercial -
'
business
zones are confined
to the Highway 17 area of ,Town (with
some off
of US Highway 17 and State Highway 50 along Sound Road
'
2 - 1

and other side roads). Many to most of the secondary roads in I
Town are unpaved gravel and/or dirt. Housing in the area '
consists mostly of single family residences; many of the houses
are older, having been built around the time the Town was '
established, and there are also a number of mobile homes within
Town limits. '
Areas of new development are appearing in Holly Ridge and the
'
adjacent areas. In the southeast corner of Town and extending
into the proposed annexation area, a sizable community is being
'
developed, with mobile home lots for rent or for sale.. Rental
housing is present in Holly Ridge, and there is a multifamily
'
apartment complex located along Center Street.
'
Its proximity to Camp Lejeune, Jacksonville, Wilmington and
the beaches, makes Holly Ridge a potentially desirable area for
growth and development. (1969 Onslow County Development Report).
In the future, one can expect Holly Ridge to experience increased
'
residential growth, including increased rental and multifamily
'
housing, as the Town evolves into a bedroom community for
commuters to the north and south/Jacksonville-Camp Lejeune and
'
Wilmington. It is particularly appealing to dual wage-earner
families who work in Wilmington and Jacksonville as Holly Ridge
'
is located approximately half way between those metropolitan
'
areas. There will be a coincident increase in commercial
vitality and an increase in services offered and extent of the '
business district. The Town of Holly Ridge may continue to
expand its corporate limits by selected annexation. ,
2 - 2 1

' 2.3 Topography, Surface Waters, Soils and Areas of Environmental
Concern (AEC's)
2.3.1 Topography and Surface Waters
The Town of Holly Ridge sits on a topographic high. The
average elevation in the area is approximately 50 - 60 feet above
mean sea level (MSL). Highest points (65 feet MSL) found within
the Town limits are along and just east of Highway 17 and along
Sound Road (see topographic maps).
Highway 17 runs roughly along a major drainage divide
separating the Northeast Cape Fear Drainage Basin from the
Coastal Drainage Basin. To the west, water flows toward the
Northeast Cape Fear River, and to the east water flows directly
toward the ocean.
' Within the study area four drainage subdivisions were
identified (see topographic maps), one being in the Northeast
' Cape Fear Drainage Basin, and the other three (3) are divisions
of the Coastal Drainage Basin.
' A creek flows eastward between Hudiberg and Pine Streets, and
' another flows northeast between Highway 17 and Sound Road. Some
groundwater recharge to the tertiary limestone aquifer of the
' Castle Hayne Formation occurs locally. To the southeast Kings
Creek and its tributaries drain into the Atlantic Intracoastal
Waterway. Waters of the Atlantic Intracoastal Waterway and
adjacent sound waters are classified "SA" for shellf ishing.
Possible sources of pollution to these waters from stormwater
trunoff include parking lots, gas stations, and poorly contained
waters from drained streets.
2 - 3

2.3.2 Soils
Map 2.3.2.1 shows the soil types present at Holly Ridge.
'
Table 2.3.2.1 provides brief descriptions of these soil types and
pertinent engineering characteristics with regard to drainage.
'
Soils information included herein is based on information
provided by the Onsl ow County office of the Soil Conservation
'
Service.
'
2.3.3 Areas of Environmental Concern
North Carolina's areas of environmental concern (AEC' s)
'
include coastal wetlands, estuarine waters and shorelines, ocean
erodible areas, and other easily disturbed coastal areas. AEC's
'
are defined and described in detail in the Coastal Area
'
Management Act Regulations.
Within the Town of Holly Ridge and the proposed annexation
,
area, there are no known AEC's. Just about a mile to the
southeast and east, however, is Cypress Creek, which drains into
,
Batts Mill Creek and the Intracoastal Waterway. Tidal flats,
marshes, and West Onslow Beach lie to the east astride the
Atlantic Ocean. All of these areas are areas of environmental
concern.
It is important that the improvements recommended in this '
plan not adversely impact any of the AEC's or affect groundwater
recharge. Engineering and regulatory control methods which can
be used to accomplish this goal are set forth in Sections 5 and 6 '
of this report.
2 - 4 ,

ro
-
Mu
Lh
st
Pt
Mu
Mu
Ur
50 Ln
Mu
Cn
Ln CAMP
Mu
DAVIS
Ln
I
L/M/rS
_ (APPROX.) Ur Ur
Ur
17
Mu
-
_
Mu
em
On
On-
M
8m
Ln
I &n
Ln Pt
Bt � �- Mu
--j--�-- amPf
Ku 8
Mu
Bm
u L n MK
pt
pt
6m pt
�h
M K
Ku 6
Ln
Bni
Ln
Ln
Brn
Pt
Mu
6m Ln
Ku8
Cn
Wa
5e
B
Sf Bm
An0
Bm Ln Nlu
MK
Ln Mu Ana Ln M
- SOURCE : USDA Soil Conservation Service
Onslow County, N.C. Soil Survey
Field Sheets, 1979.
KEY TO SOIL AND ROAD TYPES
AnB Alpin Fine Sand
Bm Baymeade Fine Sand
KuB Kureb Fine Sand
Ln Leon Fine Sand
Mk Muckolee Loam
Mu Murville Fine Sand
On Onslow Loamy Fine Sand
Pt Pits, wet, sandy
Se Seagate Fine Sand
St Stallings Loamy Fine Sand
To Torhunta Fine Sandy Loam
Ur Urban Land
Wa Wando Fine Sand
17 U.S. Route
50 State Route
NOTE:
SEE TABLE 2.3.2.1 FOR SOILS LIMITATIONS.
0 2000' 4000'
SCALE: 1 2000'

TABLE 2.3.2.1
ESTIMATED SOILS PROPERTIES SIGNIFICANT TO ENGIDIEERING
MAP SYMBOL,
DEPTH
PERMEABILITY
FLOODING
HIGH WATER TABLE
.LAND TYPES
(IN.)
(IN.1HR.)
FREQUENCY
DEPTH (FT.)
AnB - Alpine
0 - 13
2.0 - 6.0
None
>6.0
Fine Sand
13 - 48
6.0 - 20.0
BM - Bayrreade
0 - 36
6.0 - 20.0
None
4.0 - 5.0
Fine Sand
36 - 49
2.0 - 6.0
49 - 78
6.0 - 20.0
KuB - Kureb
Fine Sand
0
- 80
6.0
- 20.0
None
>6.0
Ln - Leon
0
- 15
6.0
- 20.0
None
0 - 1.0
Fine Sand
15
- 30
0.6
- 6.0
30
- 80
0.6
- 6.0
Mk - Muckalee
0
- 40
0.6
- 2.0
Frequent
0.5 - 1.5
Loam
40
- 75
0.6
- 2.0
Mu - Murville
0
- 8
6.0
- 20.0
None -Rare
0 - 1.0
Fine Sand
8
- 45
2.0
- 6.0
45
- 56
6.0
- 20.0
56
- 70
On - Onslow
0
- 17
>6.0
None
1.5 - 3.0
Loamy Fine Sand
17
- 53
2.0
- 6.0
53
- 80
0.6
- 2.0
Pt - Pits,
We t, Sandy
Se - Seagate
Fine Sand
----
6.0
- 20.0
None
1.5
- 2.5
St - Stallings
0
- 12
6.0
- 20.0
None
1.0
- 2.5
Loamy Fine Sand
0
- 12
2.0
- 20.0
12
- 42
2.0
- 6.0
42
- 80
2.0
- 20.0
To - Torhunta
-------
2.0
- 6.0
Ccmrron
0 -
1.5
Fine Sandy Loam
Ur - Urban Soil
-----
------
------
----
-
Wa - Wando
0 -
8
6.0
- 20.0
None
4.0
- 6.0
Fine Sand
8 -
99
6.0
- 20.0

i
1
1
1
1
1
i
1
1
1
1
1
1
1
1
1
1
1
1
Table 2.3.2.1, Continued
DEGREE AND KIND OF LIMITATION FOR STATED USE
MAP SYMBOL,
DWELLINGS
LAND TYPES
W/BASEMENTS
AnB - Alpine
Fine Sand
Slight
BM - Bayneade
Fine Sand
Slight
KUB - Kureb
0 - 8%: Slight
Fine Sand
8 - 15%: Moderate -
Slope
15+%: Severe -Slope
Ln - Leon
Fine Sand Severe -Wetness
Mk - Muckalee Severe -Flooding,
Loam
Wetness
Mu - Murville
Severe -Wetness
Fine Sand
Severe -Floods,
Wetness
On - Onslcw
Moderate -Wetness
Loamy Fine Sand
Pt - Pits,
Wet, Sandy
--------
Se - Seagate
Fine Sand
Severe -Wetness
St - Stallings
NxAerate-Wetness
Loamy Fine Sand
To - Torhunta
Severe -Wetness,
Fine Sandy Loam
Flooding
Ur - Urban
Soil
_---------
Wa - Wando
Slight
Fine Sand
Source: Soil Conservation Service.
LOCAL ROADS SEPTIC TANK
AND STREETS ABSORPTION FIELD
Slight Slight
Slight Moderate -Wetness
0 - 8%: Slight 0 - 15%: Severe -
Poor Filter
8 - 15%: Moderate- 15+: Severe -Poor
Slope Filter, Slope
15+%: Severe -Slope
Severe -Wetness,
-------- Poor Filter
Severe -Flooding,
--- -- Wetness
Severe -Wetness,
--- -- Poor Filter
Moderate -Wetness
Severe -Wetness,
Flooding
Severe -Wetness
Severe -Wetness,
Poor Filter
Severe -Wetness,
Flooding
Severe -Poor,
Filter

11
2.4 Climate/Rainfall Intensity and Duration
2.4.1 Climatic Summary
The National Climate Data Center in Ashville, NC has compiled
a summary description of the area climate based on the
Wilmington, NC location south of the study area. That
description is found in Appendix B.
2.4.2 Rainfall Intensity/Duration
Table 2.4.2.1 summarizes rainfall intensity and duration data
compiled from historical rainfall records by the U. S. Weather
Bureau and applicable to rainfall events in the southern coastal
area of North Carolina including Holly Ridge. Annual rainfall
for Holly Ridge averages about 52 inches based on long term
records.
2.5 Existing State Coastal Area Stormwater Control Regulations
The N. C. Environmental Management Commission (NCEMC) adopted
regulations to control stormwater runoff, effective January 1,
1988. The regulations impose certain constraints on development
in the 20 coastal counties of North Carolina with special
emphasis on controls on development proximate to estuarine waters
classified SA
(for shellfishing) .
Following is
a summary of
the
regulations.
(Note: A copy of
the complete
regulations
are
found in Appendix C.).
' Stormwater control measures are required on any, development
activities in the area of jurisdiction which require a CAMA major
development permit or a sedimentation/erosion control plan with
I
the following exceptions:
1
2 - 5

M M M M M M M M M MM
Z
TABLE 2.4.2.1
INCHES OF RAINFALL FOR VARIOUS RECURRENCE AND ACCUMULATION TIMES
FOR SOUTHERN COASTAL NORTH .CAROLINA
PERIOD OF RAINFALL COLLECTION
30 MIN
1 HR
2 HR
3 HR
6 DR
12 UR
1 DAY
2 DAY
4 DAY
7 DAY
10 DAY
1 YEAR
1.2
1.6y
2.0
2.2
2.5
3.0
3.5
2 YEAR
1.6
2.0
2.4
2.5
3.0
4.0
4.5
5.5
6.0
7.0
8.0.
5 YEAR
2.0
2.4
3.0
3.5
4.0
5.0
.6.0
7.0
8.0
9.5
10.0
10 YEAR
2.2
2.8
3.5
4.0
4.5
6.0
7.0
8.0
9.0
10.0
12.0
25 YEAR
2.6
3.4
4.0
4.5
5.0
6.5
8.0
9.0
1.1.0
13.0
14.0
50 YEAR
2.8
3.8
4.5
5.0
6.0
7.5
9.0
10.0
13.0
15.0
16.0
100 YEAR
3.0
4.0
5.0
5.5
7.0
8.5
10.0
12.0
15.0
17.0
17.0
SOURCES: Data for one day or less are from U.S. Department of Commerce,
Weather Bureau Technical. Paler No. 40, Rainfall. Frequency Atlas
of.the U.S., 1961.
Data for greater than one day are from U.S. Department of Commerce,
Weather Bureau Technical. Paper No. 49, 2-10 Day Precipitation for
Return Periods of 2-100 ears In the Contiguous II.S.

C
(1) The project site is one acre or less;
(2) The proj ect site drains to SA waters or unnamed
tributaries to SA waters and has a built upon area of 25
percent or less;
(3) The project site drains to waters other than SA and has
built upon area of 30 percent or less;
(4) The runoff from the project site is controlled through an
off -site stormwater system meeting certain provisions of
the proposed regulations and permitted; or
(5) The Director of NCDEM certifies that the site is situated
such that water quality standards and uses are not
threatened regardless of the type and degree of
development..
' Standard (non -innovative) stormwater control measures which
can be,approved according to the proposed regulations include:
(1) Stormwater infiltration devices including infiltration
' basins/ponds, swales; and
(2) Wet detention ponds.
' (3) For public roads and public bridges which minimize
impervious surfaces, divert stormwater away from surface
' waters as much as possible and employ other best
' management practices to minimize water quality impacts.
For projects draining to Class SA waters, the following
' design criteria must be observed:
(1) Direct outlet channels or pipes to SA waters are
' prohibited unless otherwise permitted in accordance with
' the regulations.
1
2 - 6

' (2) Infiltration control systems must be designed to control
the runoff from all impervious surfaces generated by one
and one-half (1.5) inches of rainfall. The size of
' the system must also take into account the runoff from
any pervious surfaces draining to the system.
' (3 ) Runoff in excess of the design volume must flow overland
through a vegetative buffer with a minimum length of 50
'
line SA waters.
feet measured from the mean high water of
'
For
projects not draining to Class SA waters, the following
design criteria are to be used:
'
(1)
Infiltration control systems must be designed to control
the runoff from all impervious surfaces generated by one
2./
(1) inch of .rainfall. The size of the system must
'
take into account the runoff from any pervious surfaces
draining to the system.
'
(2)
As a design alternative, wet detention ponds may be
designed for 85 or 90 percent removal of total suspended
'
solids.
'
(3)
Additional control measures may be required on a
case -by -case basis to protect sensitive waters or
'
specific water uses.
1./ According to Table 2.4.2.1, this represents a 2-year storm of
30 minutes duration or a one year storm of one hour duration.
2./ According to Table 2.4.2.1, this represents a 1-year storm of
30 minutes duration.
2 - 7

Infiltration systems may be designed to provide infiltration I
of the entire design rainfall volume required for a site or a I
series of successive systems may be utilized. Infiltration may
also be used to pretreat runoff to wet detention ponds. A wet '
detention pond can be used as a primary treatment device or as a
secondary device following an infiltration system. Wet detention
ponds must be designed for a specific pollutant removal according '
to modeling techniques approved by the Director of NCDEM.
Vegetative buffers can be used as a non-structural method for '
providing additional infiltration, filtering of pollutants and
minimizing stormwater impacts.
The regulations allow for the application of innovative '
measures f or controlling stormwater which are not well
established through actual experience. Such measures may be' '
approved on a demonstration basis under the following conditions:
(1) There is a reasonable expectation that the control '
'measures will be successful; '
(2) The projects are not located near sensitive waters;
(3) Monitoring requirements are included to verify the ,
performance of the control measures; and
(4) Alternatives are available if the control measures fail. '
2.6 Applicability of Existing Stormwater Control Regulations to I
Holly Ridge
1
In view of the recent adoption of the final stormwater
regulations by NCDEM, preliminary designs and control strategies '
2 8 1

FIGURE 2.6.1
11
STORMWATER SYSTEM DESIGN
EFFECTIVE 1/1/88
IS PROJECT LOCATED IN COASTAL COUNTIES, INCLUDING BEAUFORT, BERTIE, BRUNSWIC , DESIGN BASED ON EROSION CONTROL
CAMDEN, CARTERET, CHOWAN, CRAVEN, CURRITUCK, DARE, GATES, HERTFORD, HYDE, NEW IF NCI REGULATIONS BY THE STATE OR LOCAL
HANOVER, ONSLOW,_PAMLICO, PASQUOTANK, PENDER_} PERQUIMANS, TYRRELL OR WASHING- l PERMITTING AGENCY
TON? - l
15 PROJECT EXEMPT?
1. LESS THAN ONE ACRE.
2. DRAINS TO "SA" WATERS; BUILT UPON AREA < 25°06
OR
SINGLE FAMILY LOTS _> 1/3-ACRE; BUILT UPON
AREA < 2500'
AND
NO STORMWATER COLLECTION SYSTEM; BUILT UPON
AREA IS > 30 FEET FROM SURFACE WATER.
3. DRAINS TO WATERS OTHER THAN "SA"; BUILT UPON
AREA < 30 o
OR
SINGLE FAMILY LOTS > 1/3-ACRE; BUILT UPON
AREA < 300- ,
AND
NO STORMWATER COLLECTION SYSTEM; BUILT UPON
AREA IS > 30 FEET FROM SURFACE WATERS.
4. CONTROLS RUNOFF WITH OFF -SITE STORMWATER
SYSTEM PER G.S. 143-215.1(D). <
S. REDEVELOPMENT MEETS THE REQUIREMENTS AS
PRACTICAL. -
6. MEETS PROVISIONS OF DEM EXCEPT HAS BOAT RAMPS
PUBLIC ROADS AND BRIDGES WHICH MINIMIZE
JMPERVIOUS SURFACES, AND DIVERT STORMWATER
AWAY FROM SURFACE WATERS AS MUCH AS POSSIBLE
TO MINIMIZE WATER QUALITY'IMPACTS.
7. CERTIFIED BY DEM DIRECTOR THAT WATER QUALITY
NOT THREATENED.
A. NOT CLOSE TO SALINE WATERS OR FRESH
WATER NURSERY AREAS.
B.' STORMWATER CONTROLS IN LIEU OF REQUIRE-
MENTS.
IF YES
PROJECT DRAINS DIRECTLY TO "SA" WATERS
DIRECT OUTLET CHANNELS OR PIPES I
PROHIBITED
INFILTRATION CONTROL SYSTEM RUNOFF
FROM ALL IMPERVIOUS SURFACES FOR
1-1/2" RAINFALL. MUST ALSO ACCOUNT
FOR ALL AREA DRAINING TO SYSTEM.
(REQUIREMENTS LISTED AT RIGHT)
VEGETATIVE FILTER REQUIRED FOR ALL
RUNOFF IN EXCESS OF THE 1-1/2"
RAINFALL. MINIMUM WIDTH 50 FEET TO
MEAN HIGH WATER OF "SA" WATERS.
PROJECT NOT DRAINING DIRECTLY TO
"SA" WATERS
INFILTRATION SYSTEM
RUNOFF FROM ALL IMPERVIOUS SURFACES FOR 1"
RAINFALL. MUST ALSO ACCOUNT FOR ALL AREA
DRAINING TO SYSTEM.
1. MINIMUM 30 FEET FROM SURFACE WATERS;
50 FEET FOR "SA" WATERS.
2. MINIMUM 100 FEET FROM WATER SUPPLY'
WELLS.
3. BOTTOM OF SYSTEM MINIMUM OF 2 FEET
ABOVE SEASONAL HIGH WATER TABLE.
4. RUNOFF IN EXCESS OF DESIGN VOLUME BY-
PASSES SYSTEM.
5. DRAW -DOWN WITHIN 5. DAYS HYDROGEOLOGIC
EVALUATION MAY BE REQUIRED.
6. SOILS MUST HAVE MINIMUM HYDRAULIC CON-
DUCTIVITY OF 0.52 INCHES PER HOUR.
7. NOT TO BE SITED ON OR IN FILL MATERIAL.
8. OBSERVATION WELL REQUIRED FOR SYSTEM
INSPECTION.
9. IF RUNOFF IS DIRECTED TO INFILTRATION
SYSTEMS DURING CONSTRUCTION, SYSTEM
MUST BE RESTORED TO MEET DESIGN SPECS.
WET DETENTION POND
85-PERCENT REMOVAL OF TOTAL SUSPENDED
SOLIDS IN THE PERMANENT POOL AND STORAGE
OF RUNOFF FROM A 1" RAINFALL ABOVE THE
PERMANENT POOL LEVEL.
1. DESIGN STORAGE VOLUME SHALL BE ABOVE
THE PERMANENT POOL.
2. POND DRAW -DOWN IN NOT LESS THAN 2 DAYS
AND NO MORE THAN 5 DAYS.
3. MEAN DEPTH IS 3 FEET.
4. INLET STRUCTURE MUST MINIMIZE TURBU-
LENCE USING BAFFLES OR OTHER DESIGN
FEATURES.
1 5. PRETREATMENT OF RUNOFF BY USE OF IN-
FILTRATION SWALES IS ENCOURAGED TO
MINIMIZE SEDIMENTATION.
VEGETATIVE FILTER
1. DISTRIBUTION DEVICE
2. MINIMUM WIDTH 30 FEET TO RECEIVING
. STREAM
3.. NON -EROSIVE VELOCITY FOR 10-YEAR, 24-
HOUR STORM WITH A 10-YEAR, 1-HOUR IN-
TENSITY (SLOPE < 596).
3. NATURAL VEGETATION, GRASSES OR ARTIFI-
CIALLY PLANTED WETLAND VEGETATION.
0&M PLAN OR MANUAL REQUIRED,
i RESPONSIBLE PARTY
FIGURE 2.6.1

' developed in this plan will be based on the following set of
' assumptions:
• Applicability of State stormwater control regulations to
tall of Holly Ridge including the proposed annexation area.
• Appropriate and applicable exemption criteria of the
adopted regulations.
' • A "design storm" of 2 years, 30 minutes duration (1.5
inches of rain) which is the worst case situation imposed
' by the adopted regulations for discharges to SA waters.
Figure 2.6.1 presents a flow chart which illustrates how one
works through the design of stormwater control system for any
1 site at Holly Ridge.
' 2 - 9

ISECTION 3: DRAINAGE STUDY METHODS
' 3.1 General
' Following generation of the study area contour base maps, all
existing drainage structures were located and plotted on the
' maps. After this, the area within the Town limits and proposed
annexation area was divided into drainage basins. There are four
' (4) major drainage basins, as shown on the map sheets (see Appen-
dix A). Also shown on these maps are all existing drainage
structures that were located during the field survey segment of
' this study.
Once the drainage basins were defined, a meeting was held
1 with the Town on July 12, 1988 to identify the major problem
areas (areas where flooding and/or standing water occur during
major storm events) . These areas are indicated on the appended
' map sheets. Following the identification of the major problem
areas, alternatives for their proposed solution were identified
' and analyzed (see Section 4) based on anticipated run-off
I
quantities.
1 3.2 Run -Off Calculations
Where applicable, the Rational Method was used to estimate
' stormwater quantities expected within problem areas because of
' the relatively small areas involved. As set out in the basic
project requirements, the stormwater quantities were developed
for each basin for a 2-year recurrent interval rainfall event
with a 24-hour duration (4.5 inches of rain). The basic formula
3 - 1

for the Rational Method is Q =
CiA, in
which "Q" represents the
peak run-off in cubic feet per
second
(cfs), "C" is a
run-off
coefficient depending on the
physical
characteristics
of the
drainage area, "i" is the average rainfall intensity in
inches
per hour (in./hr.), and "A" is
the size
of the drainage
area in
acres (ac.).
The use of the Rational Method is based on the following
assumptions:
(1) The peak
rate
of run-off at any point
is a direct
function
of the
average rainfall intensity
during the
time of concentration to that point.
(2) The frequency of the peak discharge is the same as the
frequency of the average rainfall intensity.
(3) The time of concentration is the time required for the
run-off to become established and flow from the most
remote part of the drainage area to the point under
design.
The run-off coefficient "C" was calculated for each major
problem area using the relative degree of development. This
involved the development of a composite run-off coefficient for
each problem subbasin based on the percentage of different types
of surfaces in the drainage area. In other words, areas which
have
a high
degree
of impervious surfaces (pavement, roofs,
etc.)
will
have a
higher
composite run-off coefficient than areas
with
lesser levels of such development. For the purposes of
preliminary engineering design of drainage improvements, a
composite runoff co -efficient of 0.35 was used.
3 - 2

' The estimated quantities of stormwater run-off for each
' problem subbasin was tabulated for the 2-year design storm event.
Following the run-off calculations, an analysis of the existing
' storm drainage system was developed using the two (2) year storm
water quantities. The 2-year storm was selected as the
' "preliminary design storm" because of the prohibitive costs
'
involved
in sizing drainage systems for
larger rainfall events.
Also, the
2-year storm was used because
it forms the basis of
existing
coastal stormwater regulations
(see Section 2.5 above)
and represents
an effective control of
the "first flush" of a
rainfall
event which normally carries the bulk of pollutants to
the receiving waters.
It should be noted here that it will not be technically
' possible or economically feasible to design drainage systems or
controls to prevent all adverse effects of a severe 100-year
storm which might affect Holly Ridge. However, designing systems
and regulatory controls around the 2 year storm will prevent an
exacerbation of conditions which could turn a future 100 year
' rainfall event into a real disaster with a potential for severe
loss of life and/or property. This approach, therefore,
represents a realistic attempt to get the problem under control
now before future development or redevelopment precludes cost
effective control measures.
1
3 - 3

' SECTION 4: IDENTIFICATION OF EXISTING MAJOR DRAINAGE PROBLEM
AREAS AND THEIR POSSIBLE SOLUTIONS
' 4.1 Priorization of Projects Based on Severity of Need
A total of nine (9 ) major problem areas were identified during
' this study.
The following criteria were used in determining the priority
of the projects recommended herein. The relative importance of
'
each
of the criteria is presented in descending order: --
•
Public Health/Safety: Does the drainage problem present a
'
hazard to public safety? Will it cause or contribute to
automobile accidents? Can sufficient flooding occur to
cause injury, drowning, or limit evacuation of an area
during severe storm events which will precede a hurricane
or a northeaster?
•
Property Damage: Could drainage problems cause damage to
private property either by.flooding or by erosion caused by
'
stormwater?
high velocity
•
Receiving Waters: Could the drainage problem cause problems
in the receiving waters such as siltation, erosion or
'
closure of nearby (downstream) shellfish waters?
•
Public Nuisance: Does the stormwater cause a nuisance to
'
the public in terms of minor flooding which would interfere
with traffic or preclude temporary use of parking areas?
In addition to these objective factors listed above, public
' input from citizens and Town officials was used to modify or
adjust priorities somewhat to conform to local desires and needs.
4 - 1

"socio-political" factor is in nature, but
'
This subjective
nevertheless, influential in the development of final priorities
'
for such projects.
4.2 Problem Areas, Possible Solutions(s) and Estimated Costs
A detailed listing of the problem areas, solutions and costs
,
are shown on the following pages. The projects are presented in
'
order of descending priority based on the criteria presented in
Section 4.1 above. Each project is also displayed graphically on
'
a series of accompanying maps. It should be emphasized here that
the solutions proposed are preliminary and subject to refinement
by actual final design considerations which are yet not evident.
,
The following general comments are offered as being applicable
to all of the projects identified:
'
A general maintenance and improvements program which would
include the following basic elements is recommended:
'
1. Money budgeted annually for specific improvements.
"free"
'
2. Maintain a job list which can be worked on in
time. '
3. Suggest that at pipe crossings under a road that
debris, trees and bushes be cleared away from the '
pipe so that the pipe can be checked periodically
for blockage, etc. '
4. Suggest continual regrading of ditches as necessary
(every three to five years or as needed) .
5. That the Town seek out and determine where the old '
Camp Davis drainage system is and make improvements.
4 - 2 1

6.
Maintain good repair records so the
Town can plan
'
how often the ditches need to be cleaned
out.
Table 4.2.1
presents a summary of costs of the nine (9)
recommended
projects. The costs shown are based
on current bid
prices for
similar work in the coastal area of
North Carolina.
'
Town to
Considerable
savings may be obtained should the
elect
'
accomplish some
or all of the projects with their
own resources.
' 4.3 Maintenance of Drainage Systems
The drainage improvements recommended herein will need to be
' maintained by the Town. Periodically, sand deposits will have to
be removed from swales and drainage pipes to insure optimal
operation of these systems. Provisions need to be made in annual
' budgets for such costs.
Drainage systems on private property must also be maintained.
The proposed stormwater control ordinance presented hereinafter
(see Section 6 and Appendix D) accounts for this need in the form
of an enforceable provision.
t
11
1
4 - 3

TABLE 4.2.1
a)SP SUMMARY
DRAINAGE IN CVEME T!'S PROTECTS
TOWN OF HOLLY RIDGE, NORTH CAROLINA,
Total
Recatmiended
Construction
Oontingency
Technical
Project
Priority
Project
Subtotal
Contingency
Services
Cost
1
Highway 17 and
$ 2,300
$ 400
$ 400
$ 3,100
Highway 50
2
Camp Davis Road
& Holly Street
2,800
600
600
4,000
3
Camp Davis Road
& Lloyd Street
2,600
500
500
3,600
4
Lloyd Street
2,700
500
500
3,700
5
Jones Street:
a. Basic Project
4,600
900
900
6,400
b. New Pipe
21,600
2,200
2,200
26,000
6
Highway 50,
Jones Street to
Lloyd Street
1,750
350
350
2,450
7
Northeast Area
of Town
54,500
81000
8,000
70,500
8
Borroughs Road
Area
20,900
4,000
4,000
28,900
9
Camp Davis/
Beam St. Area
18,000
3,500
3,500
25,000
Totals
$131,750
$20,950
$20,950
$173,650

11
IProject No. 1
• Highway 17 and Highway 50 (see Map 4.2.1)
Presently, the existing ground slopes prevent stormwater
from effectively reaching the catch basin. To help prevent
flooding immediately south of Highway 50 along the west side
' of Highway 17, it is recommended that the existing catch basin
be repaired and the shoulder regraded to drain. Also, a new
' swale should be constructed in the northwest corner of the
intersection to help prevent stormwater from crossing Highway
50.
'
The Town should request
the help of the North Carolina
Department of Transportation,
since the drainage is associated
with a state highway and is
within the right-of-way of the
highway.
'
Cost Estimate
Catch basin improvements
$ 300
Roadside grading/grassing
11000
Roadside swale/grassing
11000
Construction Subtotal
$2,300
'
Contingency
400
Technical Services
400
'
Total Project Cost
$3, 100
4 - 4

REGRADE AREA
TO DRAIN
REPAIR EXISTING
CATCH BASIN
LOCATE AND CLEAN OUT
EXISTING PIPE
NC HWY 17
SCALE: I"= APPROX. 60'
HENRY VON OESEN & ASSOCIATES
CONSULTING ENGINEERS & PLANNERS
WILMINGTON, NORTH CAROLINA 28402

1
t
1
1
1
1
1
1
1
1
1
1
1
1
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1
Proj ect No. 2
• Camp Davis Road and Holly Street (see Map 4.2.2)
Stormwater sheet flows across Camp Davis Road due to lack
of drainage pipes. We recommend construction of new ditches,
the improvement of existing ditches, and a new drainage pipe
under Camp Davis Road.
Cost Estimate
18" RCP
Pavement repair
Ditch improvements
New ditch
Construction Subtotal
Contingency
Technical services
Total Project Cost
4 - 5
30
if
@ $25.00
$ 750
25
sy
@ $25.00
650
500
if
@ $ 2.00
11000
100
if
@ $ 4.00
400
$2,800
600
600
$4,000

0
a
o
Ln
c
a
a
a
i
NEW DITCH I ET
r ABANDONED
RAILROAD BED ( -*,—IMPROVE EXISTING DITCH
IMPROVE/ REGRADE N C HWY 17
EXISTING DITCH — —
NEW PIPE
SCALE: I'� APPROX. 60

Project No. 3
• Camp Davis Road and Lloyd Street (see Map 4.2.3)
Presently, water stands in the southwest corner of the
intersection, flooding septic tank systems. A drainage pipe
under Camp Davis Road is recommended. Improving the existing
drainage ditch in the area will also assist to correct the
problem.
Cost Estimate
New catch basin
18" RCP
Pavement repair
Ditch improvements
New ditch
Construction Subtotal
Contingency
Technical services
Total Project Cost
30 if @ $25.00
26 sy @ $25.00
150 if @ $ 2.00
100 if @ $ 4.00
$ 600
750
650
300
400
$2,600
500
500
$3,700
4 - 6

LO:
NEW DITCHES
50:..
la
a NEW 18R C P
REGRADE EXISTING DITCH
EXISTING 36" R C P
■�■■�t—- NEW CATCH BASIN
-�`� LLOYD STREET
SCALE: 1�=APPROX. 60

Project No. 4
e Lloyd Street (see Map 4.2.4)
Currently, water stands in the existing drainage swales on
each side of the road. To correct the situation, the roadside
swales should be regraded and driveway pipes added as
necessary.
12" RCP
Ditch improvements
New ditch
Construction Subtotal
Contingency
Technical services
Total Project Cost
4 - 7
20
if
Q
$15.00
1,000
if
@
$ 2.00
100
if
@
$ 4.00
$ 300
2,000
400
$2,700
500
500
$3,700

loi
a
0
�Q
0
a NEW DRIVEWAY PIPE
NEW DITCH
EXISTING 36" RCP EXISTING CATCH
NEW CATCH BASIN, SEE FIGURE 100't BASIN
_... �. 500t ..
LLOYD STRFFT
_...dq 500'-
EXISTING 36" R C P
SCALE: I"= APPROX. 60'

' Project No. 5
• Jones Street (see Map 4.2.5)
' Water ponds in the road just north of Camp Davis Road. It
is suspected that a portion of the old Camp Davis drainage
system between Jones and Lloyd Streets has become clogged or
experienced a failure. The line should be dewatered, cleaned
and its condition internally inspected. New drainage pipe
' should be installed as necessary along and within the street
right-of-way. Portions of the road shoulder and existing
swales should be regraded.
Cost Estimate
'
Ditch improvements 1,050 if @ $2.00
$2,100
Clean existing drain pipe 500 if @ $5.00
2,500
Construction Subtotal
$4,600
Contingency
900
Technical services
900
'
Minimum Total Project Cost
$6,400
'
If new pipe is required, add:
36" RCP 480 if C $45.00
$21,600
2,200
Contingency
'
Technical services
2,200
Maximum Total Project Cost
$32,400
4 8

REGRADE EXISTING
DITCH-,z-�
-REGRADE ROAD SHOULDER
AND EXISTING DITCHES
500'
`'-% ` EXISTING 36" RCP.
I
I
SCALE: 1�=APPROX. 60'

Project No. 6
• Highway 50 Between Jones and Lloyd Streets (see Map 4.2.6)
Stormwater currently stands in the roadside ditch on the
north side. Slight regrading of the existing ditch with some
driveway pipes should help this situation. Suggest the Town
request help from the North Carolina Department of
Transportation on this project since it is within the highway
right of way.
Cost Estimate
Ditch improvements
18" RCP
Construction Subtotal
Contingency
Technical services
Total Project Cost
500 if Q $ 2.00 $1,000
30 if Q $25.00 750
$1,750
350
350
$2,450
4 - 9

w
w
NEW DRIVEWAY
m
N
WI
z0
PIPES
}I
0
0
J
REGRADE EXISTING DITCH
500'.'-
HIGHWAY 50
d�
SCALE: 11=APPROX. 60'

U
IProject No. 7
• Northeast Area of Town (see Map 4.2.7)
tThe
area is bounded by Smith Street, Sound
Road, Dyson
Street, Kraft Street, Green Street and Crawford Street.
'
have been
Generally speaking, the roadways in this area
cleared, graded and side ditches installed some many years
ago. The side ditches have become filled in
or blocked.
'
Basically, the side ditches need to be constructed again along
with the installation of some drainage pipes. This area has a
low priority due to the fact that it is basically
undeveloped.
Cost Estimate
'
New ditches 10,000 if @ $ 4.00
$40,000
18" RCP 180 if @ $25.00
4,500
Erosion control
10,000
'
Construction Subtotal
$54,500
Contingency
8,000
Technical services
8,000
Total Project Cost
$70,500
r
1
4 - 10

NEW DITCH
9
EXISTING 15• RCP �O
NEW DITCH
5�
�� �G •, EXISTING \ 1
24"RCP
NEW DITCH
EXISTING
DITCH
,. NEW DITCH
NEW PIPE
NEW DITCH
�C
/ ,NEW PIPE
NEW PI
2 EXISTING
30" R C P
NEW PIPE
5o
�cj / SCALE: I"= APPROX. 60'
J� TOWN OF HOL
NEW DITCH /
ONSLOW COUNTY,
REGRADE EXISTING
DITCH PROPOSED DRAINAGE
5
�NORTHEAST AREA Oi
I I Cl l HENRY VON OE:

'
Project No. 8
• Borroughs Road Area (see Map 4.2.8)
This area is currently south of the
Town limits; however,
'
it is within the extraterritorial jurisdiction of the Town.
The existing drainage system consists of
roadside swales which
have filled in and become inadequate
in recent years. We
recommend that the existing ditches be
regraded and some new
ditches be constructed to correct
the current drainage
'
problems. Properly draining the area will increase the
effectiveness of the septic tank systems.
Cost Estimate
iNew
ditches 1,500 if Q
$ 4.00 $ 6,000
Ditch improvements 5,500 if @
$ 2.00 11,000
'
12" RCP 60 if Q
$15.00 900
'
Erosion control
3,000
Construction Subtotal
$20,900
'
Contingency
4,000
Technical services
4,000
Total Project Cost
$28,900
4 - 11

EXISTING 12"
PI PE -�
AI C 1Al 1 CO ii D 1 D C
DITCH E EXISTING
DITCH
NEW 12" PIPE
\'. -NEW DITCH
REGRADE EXISTING
DITCH
SCALE: I"= APPDX. 60'

Project No. 9
• Camp Davis Road/Beam Street Area (see Map 4.2.9)
This area is outside the present Town limits, but within
the extraterritorial jurisdiction limit. Portions of the area
are fairly well drained. With a few new ditches and minor
regrading, drainage will be good in this area.
Cost Estimate
New ditches on Lee Street
Ditch improvements
12" RCP
Erosion control
Construction Subtotal
Contingency
Technical services
Total Project Cost
3,000 if @ $ 4.00 $12,000
2,000
40 if @ $25.00 11000
3,000
$18,000
3,500
3,500
$25,000
4 - 12

1
iEXISTING 6'X 9'
BOX CULVERT
1
1 NEW DITCH -
EXISTING 12" RCP
1 ... LSD
EXISTING DITCH
0
cr
a EXISTING 15" RCP NEW DITCH
i W
U
O
CgMp
1
1 NEW DITCH NEW PIPE
SCALE 1-APPROX. 60'
1
TOWN OF HOLLY RIDGE
1 ONSLOW COUNTY, NORTH CAROLINA
' 4. 2 .q
PROPOSED DRAINAGE IMPRCVEMENTS
1 CAMP. DAVIS / BEAM STREET AREA
1 HENRY VON OESEN & ASSOCIATES
a I CONSULTING ENGINEERS & PLANNERS
wii uimr-rnm una-ru r^narn iun -30an�

SECTION 5: PROJECT IMPLEMENTATION
' 5.1 General
' The major drainage problems, their recommended solutions and
their estimated (preliminary) costs have been identified in the
' previous section. The projects have been prioritized. How to
' implement and fund the corrective actions are discussed in this
section.
5.2 Project Scheduling
' Each project should be implemented in order of priority as
set forth in Section 4 above. Drainage projects are inherently
' expensive and so it would be prudent to schedule only one to two
' or perhaps at the most three projects each fiscal year for
de sign/ construction until all of the major problems are
' rectified. Because of the level of importance of the highest
priority project, it may be best to proceed with it as the
' initial project in the series as a "test case" for implementation
' of all the others.
' 5.3 Project Funding Alternatives
At present, there are no applicable active state or federal
grant programs that would provide matching funds for the
' construction of drainage projects at Holly Ridge. Thus, all
projects must be accomplished with local funds. One traditional
' source of such local funds would be General Fund Revenues
supported by Ad Valorem taxes. This procedure would distribute
1
5 - 1

the cost of drainage improvements to all of the property owners I
at Holly Ridge and the proposed annexation area. However, not I
all property owners would receive direct measurable benefits from
the identified improvements and so it could possibly be argued '
that such a system would be "unfair". (Nevertheless, it remains
as a viable funding option in this case). '
Hence, in the interest of fairness and equitability, the I
basic premise in funding drainage improvements projects is that
"those who benefit share in the cost." Consistent with this '
general premise is the alternative funding tool of special
assessments which are defined in detail in Article 10 of the
General Statutes Section 160A-216 through 238. A special '
assessment program may be judged as an equitable means to fund
some or all of the identified major drainage projects defined '
abov e .
According to the General Statutes, assessments may be made on '
the basis of: I
(1) The frontage abutting on the project, at an equal rate
per foot of frontage (front foot assessment); or '
(2) The area of land served, or subj ect to being served, by
the project, at an equal rate per unit of area (areal '
assessment) ; or 1
(3) The value added to the land served by the project, or
subject to being served by it, being the difference '
between the appraised value of the land without
improvements as shown on the tax records of the county, '
and the appraised value of the land with improvements ,
5 - 2 1

' according to the appraisal standards and rules adopted
by the county at its last revaluation, at an equal rate
'
per dollar of value added (value added assessment) ; or
' (4) The number of lots served, or subject to being served,
where the project involves extension of an existing
' system to a residential or commercial subdivision, at an
equal rate per lot (lot assessment); or
' (5) A combination of two or more of these bases.
1
In cases where areal or value added assessments are selected,
the unit of government may provide for the laying out of benefit
zones according to the distance of benefited property from the
project being undertaken, and may establish differing rates of
assessment to apply uniformly throughout each benefit zone. This
provision appears to have merit in the case of Holly Ridge as
those properties immediately adjacent to a drainage structure or
improvement may benefit more than those further remote from it.
In any case, the General Statutes indicate that the unit of
government should endeavor to establish an assessment method from
among the alternative bases set out which will most accurately
assess each lot or parcel of land according to the benefit
conferred upon it by the project. The local unit of government's
decision as to the method of assessment will be final and
conclusive and not subject to further review or challenge.
The General Statutes also set forth the procedures in levying
assessments which is summarized in order of occurrence as
follows:
5 - 3

'
• Adopt Preliminary Resolution which defines the scope o
p f the
project, basis for assessments, boundaries of the area to
'
be assessed, estimated cost of the project and the portion
to be paid by assessments, terms of payment, and the date
'
of a public hearing, etc.
'
• Publication of a Notice of the Preliminary Resolution
• Conduct Public Hearing on the Preliminary Resolution
'
• Adopt Final Resolution
• Determine Cost of Project
'
• Publication of Preliminary Assessment Roll
Conduct
!
• Public Hearing of Preliminary Assessment Roll
• Revise/Confirm Assessment Roll (upon confirmation assess-
'
ment becomes alien on all the property assessed).
• Publication of Notice of Conformation of Assessment Roll
• Collection of Assessments
In
'
view of the relatively nominal cost of some of the
drainage projects at Holly Ridge, it may be appropriate to fund
'
these by ad valorem tax revenues. While, on the other hand, the
more expensive projects could be funded by an appropriate
'
assessment program. Those projects in the areas slated for
future annexation may be funded by an annexation bond referendum.
'
Those projects in relatively undeveloped areas may be funded in
part by future development interests. Finally, the assistance of
NCDOT may be respectfully requested where problems exist within
'
highway rights -of -way under the purview of NCDOT.
Table 5.3.1 presents recommended funding mechanisms for each
'
project.
'
5 - 4 1

Project No.
1
2
3
4
5
6
7
TABLE 5.3.1
RECOMMENDED PROJECT FUNDING ALTERNATIVES
TOWN OF HOLLY RIDGE, NORTH CAROLINA
Total
Recommended
Estimated Cost
Funding Option
$ 3,100
NCDOT
$ 4,000
Ad Valorem Taxes
$ 3,600
Ad Valorem Taxes
$ 3,700
Ad Valorem Taxes
$32,400
Assessment
$ 2,450
NCDOT
$70,500
Assessment or
Negotiation w/Future
Development Interests
$28,900
Annexation Bond
$25,000
Annexation Bond

ISECTION 6: LOCAL REGULATORY CONTROL STRATEGIES
' 6.1 General
' Previous sections of this report have identified the major
existing drainage problems and cost effective, environmentally
' sound engineered solutions have been proposed. An implementation
plan and funding arrangements have been identified. The focus in
this section is how best to prevent, insofar as possible, the
' creation of future drainage problems. An effective control
strategy is identified and presented along with a suggested legal
mechanism of enforcement in the form of a local stormwater
' control ordinance.
'
6.2 Strategy for Stormwater Control
The purpose of any control strategy relative to stormwater
'
and drainage is to prevent insofar as possible the creation of
additional drainage problems due to imprudent development.
'
drainage systems
• Encourage developers to incorporate sound
'
compatible with surrounding drainage system and NCDEM
stormwater regulations.
'
• Use/encourage swales, detention ponds, vegetative filters,
etc.
'
• Proper design/installation/implementation/maintenance of
'
stormwater control facilities.
• Take into account possibility of unpaved (gravel) roads
when planning new development and drainage.
• Use of porous pavement.
1
6 - 1

6.3 Draft Stormwater Control Ordinance
Several existing stormwater control ordinances were reviewed '
relative to the Holly Ridge situation. Certain elements from
several are considered applicable, and provisions from several '
model ordinances were used to formulate the basic outline of a
suggested ordinance for Holly Ridge, which is found in Appendix '
D. Major points include: '
• Consistency with the existing State Coastal Area Stormwater
Control Regulations relative to the need for permits, '
emphasis on the use of infiltration systems and vegetative
filters and applicability of the 2-year design storm, etc. '
e Requirement of submittal of a stormwater control plan for '
the development of all sites exclusive of single
residential lots. '
• Application of minimum stormwater control standards for all
development. All development must provide infiltration '
systems to control runoff from 1.5 inches of rainfall or ,
less.
The Stormwater Control Ordinance procedures also include the '
development of a permit fee schedule based upon the relative
complexity of the project and the need to formulate a Manual of ,
Stormwater Management Practices. This latter document will ,
provide developers with practical guidance in designing and
operating drainage systems consistent with the intent of the '
ordinance. The manual should contain basic design standards and
specifications for infiltration basins and trenches, dry wells, '
porous asphalt pavement, vegetated swales with or without check
1
6 - 2 1

dams, holding ponds, vegetative filter strips, etc. The
following reference publications developed by the Maryland
Department of Natural Resources should be especially useful in
this regard:
• Maryland Standards and Specifications for Stormwater
Management Infiltration Practices (February, 1984).
Maryland DNR, Annapolis, MD.
• Inspector's Guidelines Manual for Stormwater Management
Infiltration Practices (December, 1985). Maryland DNR,
Annapol is, MD.
Adoption of a final version of the suggested stormwater
control ordinance should follow traditional procedures for the
development and approval of local ordinances including ample
opportunities for public input and comment and appropriate legal
reviews prior to final promulgation. A proposed schedule for
implementation follows:
Action
• State adopts new Stormwater Control
Regulations
• Complete draft of Public Comment
Version of local Stormwater Control
Ordinance
• Public review of draft ordinance
• Conduct public hearing on draft
ordinance
• Revise draft ordinance to incorporate
results of public input
• Complete legal reviews of final
version of ordinance
• Adopt ordinance
Completion Date
January 1, 1988
March 1, 1989
(30 day period)
May 15, 19 89
June 15, 1989
July 31, 1989
August 31, 1989
1
6 - 3

SECTION 7: SUMMARY, CONCLUSIONS AND RECOMMENDATIONS
7.1 Summary and Conclusions
' The existence of drainage problems prompted the Town of Holly
Ridge, NC to engage the services of Henry von Oesen and
' Associates, Inc., Consulting Engineers and Planners, to prepare a
' Drainage Master Plan. The resultant plan is based on a set of
six (6) topographic maps at a scale of 111 - 200 feet with contour
intervals of five (5) feet which were produced as a part of the
study effort from USGS quadrangle maps. The maps which accompany
' this report (see Appendix A), show all existing drainage
' structures, the boundaries of drainage subbasins and the
locations of nine (9) major drainage problem areas.
' The Town of Holly Ridge has been supplied with mylar sepias
of the original mylars of these topographic maps for its use in
' future planning activities. Officials, staff persons,
developers, architects, engineers and private citizens will find
' these maps extremely useful in planning projects at Holly Ridge.
' Henceforth all future projects should show sensitivity to the
results of this study effort.
' For the nine (9) major drainage problem areas identified in
Section 4 of this report, appropriate solutions are proposed and
' preliminary cost estimates are presented. The total
' (preliminary) cost of design/construction of all nine projects is
estimated at $173,650. Each of the projects has been assigned a
priority based on the criteria of public safety; property damage
potential, impact on receiving waters and public nuisance
1 7 - 1

factors. It is proposed that the projects be funded by on a
case -by -case basis depending on circumstances as set forth in
Table 5.3.1 above.
Also included in the Drainage Master Plan is the basic
framework for a local regulatory strategy for stormwater control
to prevent, insofar as realistically possible, future drainage
problems caused by inappropriate or imprudent development
actions. The basis for the control strategy is a local
stormwater control ordinance which will require the submittal of
a stormwater management plan for each major development which
disturbs more than one (1) contiguous acre of land. All
development will be required to meet minimum infiltration system
requirements. Required stormwater control techniques presented
in the ordinance are based on and are in harmony with State
Coastal Area Stormwater Regulations promulgated by the N. C.
Division of Environmental Management's Environmental Management
Commission. A suggested schedule for the formulation, review,
public comment on and adoption of the local stormwater control
ordinance is provided. According to the suggested schedule, the
ordinance should be adopted by 31 August, 1989.
1
L
F
7 - 2

7.2 Recommendations
The following recommendations are offered for consideration:
' • In order to correct existing drainage problems identified
' in this report, the Town of Holly Ridge should immediately
begin a progressive program of drainage improvements in the
' nine (9) problem areas defined in this report.
• The highest priority project located at the intersection of
Highways 17 and 50 should be accomplished first. This
project should be expedited in view of the severity o
need. The Town should request the assistance of NCDOT on
rthe project.
• The drainage projects should be funded by one of several
' funding techniques on a case -by -case basis (see Table
5.3.1) .
• Concurrent with the design and construction of the drainage
' improvements in the identified problem areas, the Town
should proceed to adopt a local stormwater control
' ordinance with the following basic features:
' a. Imposition of minimum infiltration system standards for
all development.
' b. Requirement for submittal of a stormwater management
plan for the development of all new sites which exceed
' one (1) contiguous acre.
7 - 3

C. Consistency with the State's Coastal Area Stormwater
Regulations relative to design criteria for
infiltration systems, allowable percentages of
impermeable surfaces, stormwater holding ponds, design
storms, etc.
The firm of Henry von Oesen and Associates, Inc. appreciates
the opportunity to be of service in developing this plan and
stands ready to assist the Town of Holly Ridge to implement the
above recommendations.
Respectfully submitted,
HENRY VON OESEN AND ASSOCIATES, ITC.
William E. Burnett
Environmental P anner
David E. Criser, P. E.
Project Engineer
DEESS 1 py�4�y
SEAL
11270
,,�9`�D E. CR��o`•
.1
L�
7 - 4

APPENDICES
A TOPOGRAPHIC MAPS OF THE HOLLY RIDGE AREA
B CLIMATIC SUMMARY
C EXISTING COASTAL AREA STORMWATER CONTROL REGULATIONS
D MODEL STORMWATER CONTROL ORDINANCE FOR HOLLY RIDGE,
NORTH CAROL INA
1
1
1
1
1
1
1
1
1

APPENDIX A
TOPOGRAPHIC MAPS OF THE HOLLY RIDGE AREA
[MAP POCKET]

APPENDIX B
CLIMATIC SUMMARY FOR WILMINGTON, NORTH CAROLINA
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ISSN 0198-3792
LOCAL CLIMATOLOGICAL DATA ��`"` °`
V' ,f n
ANNUAL SUMMARY WITH COMPARATIVE DATA
WILMINGTON, r
f SJArES °q Pam?
NORTH CAROLINA
Daily Data CELSIUS
34
30
26
22
18
14
10
6
2
-2
-6
10 20 30 10 20 28 10 20 30 10 20 30 10 20 30 10 20 30 10 20 30 10 20 30 10 20 30 10 20 30 10 20 30 10 20 30
JAN FEB MAR APR MAY JUN JUL AUG SEP -OCT NOV DEC
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0 I I I I11111111111 I 1 I 1 1 111111 111 111111171 I 1 1
10 20 30 10 20 28 10 20 30 10 20 30 10 20 30 10 20 30 10 20 30 10 20 30 10 20 30 10 20 30 10 20 30 10 20 30
TEMPERATURE DEPICTS NORMAL MAXIMUM. NORMAL MINIMUM AND ACTUAL DAILY HIGH AND LOW VALUES (FAHRENHEIT)
PRECIPITATION IS MEASURED IN INCHES. SCALE IS NON -LINEAR
SUNSHINE IS PERCENT OF THE POSSIBLE. SUNSHINE
I CERTIFY THAT THIS IS AN OFFICIAL PUBLICATION OF THE NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, AND IS COMPILED FROM
RECORDS ON FILE AT THE NATIONAL CLIMATIC DATA CENTER, ASHEVILLE, NORTH CAROLINA, 28801
NATIONAL NATIONAL NATIONAL .0 lf✓lll�� �
DATA CENTEDIRECTOR
n o a a ATMOSPHER COCEA NIC ADMINISTRATION ANDEN AND �INFORMA ION SERVICE ENTAL SATELLITE.ATa ASHEVILLECNORTH CAROLINA NATIONAL CLIMATIC DATA CENTER

WILMINGTON,
NORTH CAROLINA
Wilmington is located in the tidewater section of
southeastern North Carolina, near the Atlantic
Ocean. The city proper is built adjacent to the
east bank of the Cape Fear River. Because of the
curvature of the coastline in this area, the ocean
lies about 5 miles east and about 20 miles south.
The surrounding terrain is typical of coastal
Carolina. It is low-lying with an average
elevation of less than 40 feet, and is
characterized by level to gently rolling land with
rivers, creeks, and lakes that frequently have
considerable swamp or marshland adjoining them.
Large wooded areas alternate with cultivated
fields.
The maritime location makes the climate of
Wilmington unusually mild for its latitude. All
wind directions from the east-northeast through
southwest have some moderating effects on
temperatures throughout the year, because the
ocean is relatively warm in winter and cool in
summer. The daily range in temperatures is
moderate compared to a continental type of
climate. As a rule, summers are quite warm and
humid, but excessive heat is rare. Sea breezes,
arriving early in the afternoon, tend to alleviate
the heat further inland. Long-term averages show
afternoon temperatures reach 00 degrees or higher
on one-third of the days in midsummer, but several
years may pass without 100 degree weather. During
the colder part of the year, numerous outbreaks
of polar air masses reach the Atlantic Coast.
causing sharp drops in temperatures. However,
these cold outbreaks are significantly moderated
by the long trajectories from the source regions.
the effects of passing over the Appalachian Range,
and the warming effects of the ocean air.
As a result, most winters are short and quite
mild. Even in the most severe cold spells, the
temperature usually remains above zero. Normally,
the temperature fails to rise above the freezing
point during a 24-hour period only once each
winter.
11
11
Rainfall in this area is usually ample and
well -distributed throughout the year, the greatest
amount occurring in the summer. Summer rainfall
comes principally from thunderstorms. and is
therefore usually of short duration, but often
heavy and unevenly distributed. Thunderstorms
occur about one out of three days from June
through August. Winter rain is more likely to be
of the slow, steady type, lasting one or two days.
Generally, the winter rain is evenly distributed
and associated with slow -moving. low-pressure
systems. Seldom is there a winter without a few
flakes of snow, but several years may pass without
a measurable amount, and appreciable accumulation
on the ground is rare. Hail occurs less than once
a year. Sunshine is abundant. with the area
receiving about two-thirds of the sunshine hours
possible at its latitude.
Because of these many factors, the growing season
is long, averaging 244 days, but records show the
range is from 180 days to as long as 302 days.
This area is exceptionally good for floriculture.
Agricultural pursuits, principally ' field -grown
flowers, nursery plantings, and vegetables, are an
important part of the economy. Some types of
plants continue to grow throughout the year.
In common with most Atlantic Coastal localities,
the area_ is subject to the effects of coastal
storms and occasional hurricanes which produce
high winds, above normal tides, and heavy rains.

I
APPENDIX C
1 EXISTING COASTAL AREA STORMWATER CONTROL REGULATIONS
1
J
I�
1

15 NCAC 2H .1001-.1003; have been adopted as published in the
NCR, Volume 2, Issue 4, pages 250-253, with changes, as follows:
SECTION .1000 - STORMWATER RUNOFF DISPOSAL
.1001 STORMWATER DISPOSAL POLICY
(a) The increase in stormwater runoff associated with land
development activities can substantially increase inputs of -waste
constituents present in stormwater to waters of the State over
that which occurs in natural, undeveloped watersheds. The
increased pollutant loading from stormwater runoff may degrade
ambient water quality, adversely impact best usage or otherwise
viol -ate water quality standards. For these reasons, it is the
goal of the Commission to minimize any water quality impacts of
development activities to ensure that existing and designated
uses are maintained and protected in accordance with the
provisions of this Section. In estabi•ish-ing this goai, the
Commission recognizes that the U.S. Environmental Protection
Agency will be establishing permit requirements and best
management practices for stormwater point sources pursuant to the
Federal Water Pollution Control Act as amended.
(b) The rules in this section to control pollutants
associated with stormwater runoff apply to development of land
for residential, commercial, industrial,- or institutional use
but do not apply to land management activities associated with
agriculture or silviculture.
History Note: Statutory Authority G.S. 143-214.1;
143-215.3(a)(1);
Eff. January 1, 1988.
.1002 DEFINITIONS
The definition of any word or phrase in this Section shall be
the same as given in Article 21, Chapter 143 of the General
Statutes of North Carolina, as amended. Other words and phrases
used in this Section are defined as follows:
(1) Development means any land disturbing activity which
adds to or changes the amount of impervious or
partially impervious cover on a land area or which
otherwise decreases the infiltration of precipitation
into the soil thus altering the hydrological
characteristics of the area.
(2) Drainage area or watershed means that area
contributing runoff to a single point measured in a
horizontal. plane which i.s enclosed by a ridge line.
(3) Infiltration systems mean stormwater treatment systems
designed -to allow runoff to pass or move (infiltrate)
into the soil surface.
(4) On -site stormwater systems mean the systems necessary
to control stormwater within an individual development
project.
(5) Off -site stormwater systems mean the systems necessary
to control stormwater from more than one development
which is owned and operated as a duly licensed utility
or by a local government.
1

(6) Built -upon area means that portion of an individual
development
'
project that is covered by impervious or
Partially impervious
cover including buildings,
pavement, recreation facilities,
'
decking. etc. but not including
(7) Redevelopment means any rebuilding activity following
fires, hurricanes
or other natural disaster, or other
-public restoration projects designated by
'
Commission; the
(8) Wet detention pond means a structure that provides for
the storage and treatment
'
of runoff and includes a
permanent -pool of water.
(9) Coastal Counties include Beaufort,
Camden, Carteret,-Chowan,
'
Craven, Currituck, Dare,ck,
Gates, Hertford, Hyde, New Hanover, Onslow,
Pasquotank,
Pamlico,
Pender, Perquimans, Tyrrell, and
Washington. -
(10) Sedimentation/erosion
control plan means any plan
submitted to the Division of Land Resources
or
delegated authority in accordance with 15 NCAC 48
.0005.
'
(lI) CAMA major development permits mean those permits
required by the Coastal
Resources Commission according
to 15 NCAC 7J Sections
'
.0100 and .0200.
(12) Vegetative filter means an area of natural or planted
vegetation. through
which stormwater runoff flows
in a diffuse manner so that
runoff does not become
channelized and which provides for infiltration
'
of
runoff and filtering"of pollutants. The direction of
stormwater flow defines
the width of the filter.
(13) Stormwater collection system means
'
any pipe, channel,
curb or gutter for the prima'ry
purpose of transporting
(not treating) runoff but does not include
grassed
swales, or pipes used to carry drainage underneath
built -upon surfaces
that are associated with
development controlled by the
provisions
of Rule .1003(a)(2) and (3) in this Section.
'
History Note: Statutory Authority G.S. 143-214.1;
143-215.3(a)(1);
Eff. January 1, lggg.
'
.1003 COASTAL STORMWATER DISPOSAL
(a) Applicability. The intent of the Commission is to achieve
the water quality protection
'
which low density development near
productive coastal waters would provide. To that
director
end, the
by applying the standards in this Rule will cause
development to
comply with the antidegradation requirements
specified in 15 NCAC 2B
'
.0201 by protecting high quality waters
and highly productive aquatic resources
from the adverse impacts
of uncontrolled high density development
or the potential failure
Of stormwater control measures. Stormwater control measures as
described in Paragraphs
(c) through (1 ) of this Rule are
required for any development
activities in
which require a CAMA major development the coastal counties
,
permit or a
.1

1
sedimentation/erosion control plan after January 1, 1988 unless
the development:
(1) is one acre or less;
(2) drains to SA waters or unnamed tributaries to SA
waters; has a built -upon area of 25Z or less, or
proposes development of single-family residences on
lots with one-third of an acre or greater with a
built -upon area of 25« or less; has no stormwater
collection system; and built -upon area is at least 30
feet from surface waters;
(3) drains to waters other. than SA; has a built -upon area
of 30% or less, or proposes development of
single-family residences on lots with one-third of an
acre or greater with a built -upon area of 30% or
less; has no stormwater collection system; and
built -upon area is at least 30 feet from surface
waters;
(4) controls runoff through an off -site stormwater system
meeting provisions of this Rule and permitted in
accordance with G.S. 143-215.1(d); .
(5) is redevelopment which meets the requirements of this
Rule to the maximum extent practicable;
(6) otherwise meets the provisions of this Rule and has
boat ramps, public roads and public bridges which
minimize impervious surfaces, divert stormwater away
from surface waters as much as possible and employ
other best management practices to minimize water
quality impacts; or
(7) is certified by the Director that the site is situated
such that water quality. standards. and uses are not
threatened and the developer_ demonstrates. that the
development meets the follow.i-ng"criteria:
(A) the plans and specifications - indicate stormwater
control measures which will be installed in lieu
of the requirements of this Rule, or
(B) the development is located such a distance from
surface waters that impacts from pollutants
present in stormwater from the site will be
effectively mitigated;
Development designed to meet the low density requirements in
subparagraphs (2) and (3) of this Paragraph must demonstrate that
no areas within the project site are of such high density that
stormwater threatens water quality. Deed restrictions and
protective covenants used to ensure that subdivisions
maintain the development consistent with the plans and
specifications approved by the division will include the State
as a beneficiary of the restrictions.
(b) Projects with stormwater control measures in accordance
with the provisions of this Rule shall be deemed permitted
pursuant to C.S. 143-215.1(d) upon receipt of a permit from the
Division of Coastal Management or plan approval from the Division
of Land Resources (or delegated authority). In addition, NPOES
permits for stormwater point sources may be required according to
the provisions of 15 NCAC 2H .0126.

(c) Stormwater Control Options. Stormwater control measures
which can be approved pursuant to this Rule and which will not be
considered innovative include:
(1) Stormwater infiltration systems including infiltration
basins/ponds, swales, and vegetative filters; and
(2) Wet detention ponds.
(d) Innovative Systems. Innovative measures for controlling
stormwater which are not well established through actual
experience may be approved on a demonstration basis under the
following conditions:
(1) There is a reasonable expectation that the control
measures will be successful;
(2) The projects are not located near high quality waters;
(3) Monitoring requirements are included to verify the
performance of the control measures; and
(4) Alternatives are available if the control measures
fail and will be required when the director
determines that the system has failed;
No more than five projects utilizing the same innovative control
measure will be approved until the technology is proven over a
time frame to be determined on a case -by -case basis. These five
projects will include projects approved since November 1, 1986
according to the provisions of 15 NCAC 2H .0408.
(e) Design Criteria for -Development Draining to Outstanding
Resource Waters. Stormwater control requirements to protect
coastal waters classified as Outstanding Resource Waters (ORW)_ pursuant to 15 NCAC 2B .0216 shall be determined in the process
to reclassify the waters as ORW. After the Commision has received
a request to classify Class SA waters as ORW and given permission
to the director to schedule a public hearing to consider
reclassification, and until such time as specific stormwater
design criteria become effective, only .development which meets
the requirements of Paragraph (a) (2), (5) or (6) will be
approved within 575 feet of mean high water of these waters.
(f) Design Criteria for Development draining directly to
Class SA waters.
(1) Direct outlet channels or pipes to SA waters are
prohibited unless permitted in accordance with 15 NCAC
2H .0126.
(2) Infiltration control systems must be designed to
control the runoff from all impervious surfaces
generated by one and one-half inches of rainfall. The
size of the system must take into account the runoff
from any pervious surfaces draining to the system.
(3) Runoff in excess of the design volume must flow
overland through a vegetative filter with -a minimum
width of 50 feet measured from mean high water of SA
waters;
(g) Design Criteria For Development Not Draining to
SA Waters.
(1) Infiltration control systems must be designed to
control the runoff from all impervious surfaces
generated by one inch of rainfall. The size of the
system must take into account the runoff from any
pervious surfaces draining to the syst('ra;
.1
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C
J

7
(2) Wet detention ponds must be designed according to
methods approved by the director for 85 percent
removal of total suspended solids in the permanent
pool and storage of runoff from a one inch rainfall
from the site above the permanent pool;
(3) Vegetative filters are required for the overflow and
discharge of all stormwater from wet detention ponds;
these filters shall be at least 30 feet in length;
(4) Additional control measures may be required on a
case -by -case basis to protect high quality waters or
specific water uses.
(h) Infiltration System -Requirements. Infiltration systems
may be designed to provide infiltration of the entire design
rainfall volume required for a site or a series of successive
systems may be utilized. Infiltration may also be used to
pretreat runoff prior to disposal in a wet detention ponds. The
following are requirements:
(1) Infiltration systems shall be a minimum of 30 feet
from surface waters and 50 feet from Class SA waters;
(2) Infiltration systems shall be a minimum distance of
100 feet from water supply wells;
(3) The bottom of infiltration systems shall be a minimum
of 2 feet above the seasonal high water table;
(4) Infiltration systems must be designed such that runoff
in excess of the design volume by-passes the system
and does not flush pollutants through the system;
(5) Infiltration systems must be designed to completely
draw down to pre -storm levels within 5 days and a
hydrogeologic evaluation may be required to determine
whether the system can draw down In 5 days;
(6) Soils must have a minimum hydraulic conductivity of
0.52 inches per hour to be siiitable for infiltration;
(7) Infiltration systems must not be sited on or in fill
material;
(8) Infiltration systems must have an observation well to
provide ready inspection of the system;
(9) If. runoff is directed to infiltration systems during
construction -of the project, the system must be
restored to design specifications after the project
is complete and the entire drainage area is
stabilized.
(i) Wet Detention Pond Requirements. These practices can be
used as a primary treatment device or as a secondary device
following an infiltration system. Wet detention ponds shall be
designed for a specific pollutant removal according to modeling
techniques approved by the director. Specific requirements for
these systems are as follows:
(1) The design storage volume shall be above the permanent
pool;
(2) The discharge rate from these systems following the
one inch rainfall design storm shall be such that the
runoff does not draw down to the permanent pool level
in less than 2 days and that the pond is drawn down to
the permanent pool level within at least S days;
(3) The mean depth shall be a minimum of 3 feet;

'
(4) The inlet structure must be designed to minimize
turbulence using baffles or other appropriate design
features;
(5) Pretreatment of the runoff by the use of infiltration
'
swales is encouraged to minimize sedimentation and
eutrophication -of the detention pond.
(J) Vegetative Filter Requirements. Vegetative filters
'
shall be used as a non-structural method for providing additional
infiltration, filtering of pollutants and minimizing stormwater
impacts. Requirements for these filters are as follows:
t
(1) A distribution device such as a swale shall be used to
provl-de even -di-s"tr'ibution of runoff over the length of
the vegetative filter;
(2) The slope and width of the vegetative filter shall be
'
determined so as to provide a non -erosive velocity of
flow -through the filter for a 10-year, 24-hour storin
with a 10-year, 1-hour intensity and the portion of
'
the filter representing the minimum filter width
specified in Paragraphs (f) and (9) of this Rule shall
have a slope of .5' or less;
'
(3) Vegetation in the filter may be natural vegetation,
grasses or artificially planted wetland vegetation
appropriate for the site characteristics;
(k) Operation and maintenance plans. An operation and
'
maintenance plan or manual shall be provided by the developer for
stormwater systems, indicating what operation and maintenance
actions are needed, what specific quantitative criteria will be
'
used for determining when those actions are to be taken, and who
is responsible for those actions prior to approval of the
development by the division . The plan must clearly indicate the
steps that will be taken and who will be responsible for
'
restoring a stormwater system to design: specifications if a
failure occurs and will include an acknowledgement by the
responsible party. Development must be maintained consistent
'
with the requirements in these plans and modifications to these
plans must be approved by the Division.
(1) System Design. Stormwater systems must be designed by a
'
North Carolina registered .-professional with qualifications
appropriate for the type of system required; these registered
professionals are defined as:
(1) professional engineers;
'
(2) landscape architects, to the extent that the General
Statutes, Chapter 89A, allow; and
(3) registered land surveyors, to the extent that the
'
design represents incidental drainage within a
subdivision, as provided in General Statute 89C-3(7).
Upon completion of construction, a registered professional
'
appropriate for the type of stormwater system designed must
certify that the system was inspected during construction and was
constructed in substantial conformity with plans and
specifications reviewed by the division and complies with the
'
requirements of this Rule.

History Note; Statutory Authority G.S. 143-214.1;
143-215.1(d); 143-215.3(a)(1);
Eff. January 1, 1988.

15 NCAC 2H .1004; has been adopted as published in h
Volume 2, Issue 4, t e NCR,
'
page 253, as follows:
.1004 STATEWIDE STORMWATER GUIDELINES
The
'
division will periodically develop guidelines for the
control of stormwater pollution
from various development
practices and to protect specific water uses;
will
'
these guidelines
be provided to requesting individuals, institutions,
governments,
local
or state/federal agencies on request for use in
developing control strategies for
Pollution. mitigating stormwater
'
History Note: Statutory Authority G.S. 143-214.1;
_
143-215.3(a)(1); 143-215.8A;
Eff. January 1, 1988.
1

15 NCAC 2H .1004; has been adopted as published in the NCR,
Volume 2, Issue 4, page 253, as follows:
.1004 STATEWIDE STORMWATER GUIDELINES
The division will periodically develop guidelines for the
control of stormwater pollution from various development
practices and to protect specific water uses; these guidelines
will be provided to requesting individuals, institutions, local
governments, or state/federal agencies on request for use in
developing control strategies for mitigating stormwater
Pollution.
History Note: Statutory Authority G.S. 143-214.1;
143-215.3(a)(1); 143-215.8A;
Eff. January 1, 1988.

APPENDIX D
MODEL STORMWATER CONTROL ORDINANCE FOR
HOLLY RiDGE NORTH CAROLINA
NOTE: The following draft ordinance is based in part on the
following source document:
Frank E. Maloney, Richard G. Hamann and Bram D. E.
Canter. October, 1980. "Stormwater Runoff Control: A
Model Ordinance for Meeting Local Water Quality
Management Needs." Natural Resources Journal 20:
713-764. .

L
INTRODUCTORY NOTE:
• Concept Behind The Model Ordinance: The presumption under-
lying the Model Stormwater Control Ordinance is that land
development can be accommodated on almost any site without
resulting in irreparable damage to local water resources
and the biological community. Land can and should be used
in a manner that minimizes or avoids adverse environmental
impacts. The choice is not between development or no
development; it is between wise development or destructive
development. The Model Stormwater Control Ordinance was
developed to encourage a more harmonious relationship
between land alteration for human use and the needs of the
natural environment.
The Model Ordinance is intended to require the
implementation of stormwater runoff management practices
that accomplish two basic objectives:
1. Protect the absorptive, purifying and retentive
functions of natural systems that exist on the
site of a proposed development; and
2. Provide for post -development stormwater runoff
characteristics that resemble the conditions that
existed before the site's alteration.
The Model Stormwater Control Ordinance is designed to
be adapted to the unique characteristics of the Town of
Holly Ridge, NC specifically and to other coastal area
communities in general. It is presumed that some
provisions of the Model Ordinance will be modified or
possibly even rejected altogether. Other provisions may
have to be added. Nevertheless, the regulatory approach
and the means that were formulated to accomplish stormwater
runoff control in the Model Ordinance should greatly
facilitate the creation of effective controls in areas
where no controls presently exist and to meet the
requirements of the NC Coastal Area Stormwater Regulations
promulgated by the NC Division of Environmental Management.
SECTION ONE: SHORT TITLE
This ordinance shall be known as the "Stormwater Control
Ordinance for Holly Ridge, NC."
01

1
SECTION TWO: FINDINGS OF FACTS 1
The Board of Commissioners of the Town of Holly Ridge finds
that uncontrolled drainage development of land has a significant '
adverse impact upon the health, safety and welfare of the
community. More specifically,
(a) Stormwater runoff can carry pollutants into receiving ,
water bodies, degrading water quality;
(b) The increase in nutrients such as phosphorus and ,
nitrogen accelerates eutrophication of receiving waters,
adversely affecting flora and fauna;
(c) Improperly channeling water increases the velocity of
runoff, thereby increasing erosion and sedimentation;
(d) Construction requiring the alteration of natural '
topography and removal of vegetation tends to cause a loss of
natural recharge areas and increase erosion;
(e) Siltation of water bodies resulting from increased '
erosion decreases their capacity to hold and transport water, and
harms flora and fauna;
(f) Impervious surfaces increase the volume and rate of '
stormwater runoff and allow less water to percolate into the
soil, thereby decreasing groundwater recharge; '
(g) Improperly managed stormwater runoff can increase the
incidence of flooding and the level of floods which occur, '
endangering property and human life;
(h) Many future problems can be avoided if land is
developed in accordance with sound stormwater runoff management '
practices.
SECTION THREE: OBJECTIVES ,
In order to protect, maintain, and enhance both the immediate
and the long term health, safety and general welfare of the
citizens of the Town of Holly Ridge, NC this ordinance has the
following objectives:
(a) To encourage productive and enjoyable harmony between
humanity and nature;
(b) To protect, restore and maintain the chemical, physical 1
and biological integrity of area streams and creeks;
2

' (c) To prevent individuals, business organizations and
governments from causing harm to the community by activities
which adversely affect water resources,
(d) To encourage the construction of drainage systems which
aesthetically and functionally approximate natural systems;
' (e) To encourage the protection of natural systems and the
use of them in ways which do not impair their beneficial
functioning;
' (f) To encourage the use of drainage systems which minimize
the consumption of electrical energy or petroleum fuels to move
water, remove pollutants, or maintain the systems;
' (g) To minimize the transport of pollutants to area surface
waters;
' (h) To maintain or restore groundwater levels;
(i) To protect, maintain or restore natural salinity levels
1 in downstream estuarine areas;
(j) -To minimize erosion and sedimentation;
' (k) To prevent damage to wetlands and to the local natural
recharge areas;
' (1) To prevent damage from flooding, while recognizing that
natural fluctuations in water levels are beneficial;
' (m) To protect, restore, and maintain the habitat of fish
and wildlife; and
' (n) To ensure the attainment of these objectives by
requiring the approval and implementation of stormwater
management plans for all activities which may have an adverse
' impact upon community waters.
SECTION FOUR: DEFINITIONS
' Unless specifically defined below, words or phrases shall be
interpreted so as to give them the meaning they have in common
' usage and to give this ordinance its most effective application.
Words used in singular shall include the plural and the plural
the singular; words used in the present tense shall include the
future tense. The word "shall" connotes mandatory and not
' discretionary; the word "may" is permissive.
(a) "Adverse Impacts" are any modifications, alterations or
effects on a feature or characteristic of community waters or
3

wetlands, including their quality, quantity, hydrodynamics, ,
surface area, species composition, living resources, aesthetics
or usefulness for human or natural uses which are or may
potentially be harmful or injurious to human health, welfare, '
safety or property, to biological productivity, diversity, or
stability or which unreasonably interfere with the enjoyment of
life or property, including outdoor recreation. The term
includes secondary and cumulative as well as direct impacts. '
(b)
"Clearing" means the removal of trees and brush from
the land
but shall not include the ordinary mowing
of grass.
'
(c)
"Detention" refers to the collection
and storage of
surface
water for subsequent gradual discharge.
,
(d)
"Developer" means any person who engages
in development
either
as the Owner or as the agent of an Owner of
property.
"Development" "Development
,
(e)
or Activity"
means:
(1) the construction, installation, alteration, '
demolition or removal of a structure, impervious surface, or
drainage facility; or
(2) clearing, scraping, grubbing, or otherwise ,
removing or killing the vegetation of a site;
(3) adding, removing, exposing, excavating, leveling,
,
grading, digging, burrowing, dumping, piling, dredging, or
otherwise significantly disturbing the soil, mud, sand or
rock of a site.
'
(f) "Drainage Facility" means any component of the drainage
system.
"Drainage
'
(g) System" is the system through which water
flows from the land. It includes all watercourses, waterbodies
and wetlands.
'
(h) "Erosion" is the wearing or washing away of soil by the
action of wind or water.
'
(i) "Flood" is a temporary rise in the level of any
waterbody, watercourse or wetland which results in the inundation
of areas not ordinarily covered by water.
,
(j) "Impervious Surface" means a surface which has been
compacted or covered with a layer of material so that it is
highly resistant to infiltration by water. It includes
'
semi -impervious surfaces such as compacted clay, as well as most
conventionally surfaced streets, roofs, sidewalks, parking lots
and other similar structures.
'
4

11
' (k) "Natural Systems" means systems which predominantly
consist of or use those communities of plants, animals, bacteria
and other flora and fauna which occur indigenously on the land,
in the soil or in the water.
(1) "Owner" is the person in who is vested the fee
ownership, dominion, or title of property, i.e., the proprietor.
This term may also include a tenant, if chargeable under his
lease for the maintenance of the property, and any agent of the
Owner or tenant including a developer.
' (m) "Person" means any and all persons, natural or
artificial and includes any individual, firm, corporation,
' government agency, business trust, estate, trust, partnership,
association, two or more persons having a joint or common
interest, or any other legal entity.
' (n) "Predevelopment Conditions" are those conditions which
existed before alteration, resulting from human activity, of the
natural topography, vegetation and rate, volume or direction of
surface or ground water flow, as indicated by the best available
historical data.
(o) "Receiving Bodies of Water" shall mean any waterbodies,
watercourses or wetlands into which surface waters flow either
naturally, in manmade ditches, or in a closed conduit system.
' (p) "Retention" refers to the collection and storage of
runoff without subsequent discharge to surface waters.
(q) "Sediment" is fine particulate material, whether
mineral or organic, that is in suspension or has settled in a
waterbody.
(r) "Sedimentation Facility" means any structure or area
which is designed to hold runoff water until suspended sediments
' have settled.
(s) "Site" means any tract, lot or parcel of land or
combination of tracts, lots, or parcels of land which are in one
ownership, or are contiguous and in diverse ownership where
development is to be performed as part of a unit, subdivision, or
project.
(t) "Stormwater Management Plan" refers to the detailed
analysis required by Section Six for each activity described in
Section Five of this ordinance.
' (u) "Structure" means that which is built or constructed,
an edifice or building of any kind, or any piece of work
5

artificially built up or composed of parts joined together in
some definite manner but shall not include fences or signs.
,
(v) "Subdivide" means to divide the ownership of a parcel
of land, whether improved or unimproved, into three or more
'
contiguous lots or parcels of land, whether by reference to a
plat, by metes and bounds or otherwise, or, if the establishment
of a new street is involved, any division of a parcel of land.
Subdivision includes a resubdivision and, when appropriate to the
'
context, relates to the process of subdividing or to the land
subdivided.
'
(w) "Vegetation" means all plant growth, especially trees,
shrubs, vines, ferns, mosses and grasses.
(x) "Waters" or "Communi-ty of Waters" means any and all
water on or beneath the surface of the ground. It includes the
water in any watercourse, waterbody or drainage system. It also
includes diffused surface water and water percolating, standing
,
or flowing beneath the surface of the ground, as well as coastal
waters.
(y) "Watercourse" means any natural or artificial stream,
river, creek, channel, ditch canal, conduit, culvert, drain,
waterway, gully, ravine, street, roadway, swale, or wash in which
'
water flows in a definite direction, either continuously or
intermittently, and which has a definite channel, bed or banks.
(z) "Waterbody" means any natural or artificial pond, lake,
'
reservoir or other area which ordinarily or intermittently
contains water and which has a discernible shoreline.
,
(aa) "Watershed" means a drainage area or drainage basin
contributing to the flow of water in a receiving body of water.
"Wetlands" those
,
(bb) means areas where
(1) the soil is ordinarily saturated with water; or '
(2) the dominant plant community is one or more of those
specifies designated by the U.S. Army Corps of Engineers as
identifying 11404" wetlands or the transitional zone of '
wetlands.
SECTION FIVE: APPLICABILITY I
(a) All development within the Town of Holly Ridge, and if
ultimately incorporated, the proposed annexation area, must
comply with minimum stormwater control standards. All
development must provide appropriate infiltration devices to
control runoff of the first 1.5 inches of rainfall or less from '
6

all impervious surfaces onsite. Flow from gutters and downspouts
' shall be diverted to dry wells or porous drain pipes in rock
envelope. For structures without gutters and downspouts, gravel
infiltration beds under roof overhangs shall be provided.
Typical designs of appropriate systems will be provided for
guidance in the manual of stormwater management practices (see
Section 11).
' (b) Unless exempted pursuant to subsection (c) or waived
pursuant to subsection (d), a Stormwater Management Plan must be
submitted and approved before:
(1) a plat is recorded or land is subdivided; or
' (2) an existing -drainage system is altered, rerouted,
deepened.
(3) building permit is issued.
(4) development is commenced.
(c) Exemptions: The following development activities are
exempt from the Stormwater Management Plan Requirement:
' (1) the development of one (1) single family or duplex
residential dwelling unit and accessory structures (such as
fences, storage sheds and septic tanks) in an existing
' subdivision;
(2) the development of one (1) single family or duplex
residential structure not in an existing subdivision;
(3) agricultural activity not involving the artificial
drainage of land;
' (4) any maintenance, alteration, use or improvement to
an existing structure not changing or affecting quality,
rate, volume or location of surface water discharge.
(d) Waivers:
' (1) A waiver of the Stormwater Management Plan
requirement may be obtained by submitting an application on
forms supplied by the Town of Holly Ridge. The application
shall contain:
(i) the name, address and telephone number of the
developer and owner; and
(ii) a description and a drawing of the proposed
development; and
7

(iii) the location of the development; and
(iv) any other information requested by the Town of
Holly Ridge that is reasonably necessary to evaluate the
proposed development.
(2) The Town of Holly Ridge may grant waiver if the
application demonstrates the development is not likely to:
(i) significantly increase or decrease the rate or
volume of surface water runoff;
(i i) have a significant adverse impact on a 11404"
wetland, watercourse or waterbody;
(iii) significantly contribute to the degradation
of water quality.
(3 ) The following types of development shall not be
eligible to receive a waiver;
(i) shopping centers;
(ii) commercial facilities
(iii) subdivisions;
(iv) roads;
(v) impervious surfaces greater than 10,000 square
feet.
(e) Variances: The Town of Holly Ridge may grant a written
variance from any requirement of this ordinance using the
following criteria:
(1) there are special circumstances applicable to the
subject property of its intended use; and,
(2) the granting of the variance will not;
(i) significantly increase or decrease the rate or
volume of surface water runoff;
(i i) have a significant adverse impact on a 11404"
wetland, watercourse or waterbody.
(iii) significantly contribute to the degradation
of water quality;
(iv) otherwise significantly impair attainment of
the objectives of this ordinance.

'J i
J
1
SECTION SIX: CONTENTS OF THE STORMWATER MANAGEMENT PLAN
(a) It is the responsibility of an applicant to include in
the Stormwater Management Plan sufficient information for the
Town of Holly Ridge or its agents to evaluate the environmental
characteristics of the affected areas, the potential and
predicted impacts of the proposed activity on area surface
waters, and the effectiveness and acceptability of those measures
proposed by the applicant for reducing adverse impacts. The
Stormwater Management Plan shall contain maps, charts, graphs,
tables, photographs, narrative descriptions and explanations and
citations to supporting references, as appropriate, to
communicate the information required by this section.
(b) The Stormwater Management Plan shall contain the name,
address and telephone number of the owner and the developer. In
addition, the legal description of the property shall be
provided, and its location with reference to such landmarks as
major waterbodies, adjoining roads, or subdivisions shall be
clearly identified by a map.
(c) The existing environmental and hydrologic conditions of
the site and of receiving waters and wetlands shall be described
in detail, including the following:
(1) the direction, flow rate, and volume of . stormwater
runoff under existing conditions and, to the extend
practicable, predevelopment conditions;
(2) the location of areas on the site where stormwater
collects or percolates into the ground as shown on the
topographic maps of the Town which are on file at Town Hall;
(3) a description of all watercourses, waterbodies and
wetlands on or adjacent to the site or into which stormwater
flows. Information regarding their water quality and the
current water quality classification, if any, given them by
the NC Division of Environmental Management (NCDEM) shall be
included;
(4) groundwater levels, including seasonal fluctuations;
(5) location of flood plains;
( 6 ) vegetation;
( 7 ) topography;
(8) soils.
(d) Proposed alterations of the site shall be described in
detail, including:
0

(1) changes in topography; ,
(2) areas where vegetation will be cleared or otherwise '
killed;
(3) areas that will be covered with an impervious
surface and a description of the surfacing material; '
(4) the size and location of any buildings or other
structures. ,
(e) Predicted impacts of the proposed development on
existing conditions shall be_described in detail, including: ,
(1) changes in water quality,
(2) changes in groundwater levels;
(3) changes in the incidence and duration of flooding on
the site and upstream and downstream from it;
(4) impacts on wetlands; and
(5 ) impacts on vegetation.
'
(f) All components of the drainage system and any measures
for the detention, retention, or infiltration of water or for the
protection of water quality shall be described in detail,
,
including:
(1) the channel, direction, flow rate, volume and
'
quality of stormwater that will be conveyed from the site;
with a comparison to existing conditions and, to the extent
practicable, predev elopment conditions;
(2) detention and retention areas, including plans for
the discharge of contained waters, maintenance plans, and
predictions of water quality in those areas;
'
(3) areas of the site to be used or reserved for
percolation including a prediction of the impact on
'
groundwater quality;
(4) a plan for the control of erosion and sedimentation '
which describes in detail the type and location of control
measures, the stage of development at which they will be put
into place or used, and provisions for their maintenance;
(5) any other information which the developer or the
Town of Holly Ridge or its agents believes is reasonably
necessary for an evaluation of the development. ,
10

L�
' SECTION SEVEN: PROCEDURES AND FEES
(a) Any person planning a development
ordinance, unless exempted, shall submit a
Plan or an application for waiver to the To
wn
as def fined in this
Stormwater Management
of Holly Ridge.
(b) Within ten (10) working days after submission of the
completed waiver application, the Town shall notify the applicant
that the waiver has been approved or denied and whether a
Stormwater Management Plan must be submitted by the applicant.
(c) A permit fee will be collected at the time the
Stormwater Management Pl-an or application for waiver are
submitted and will reflect -the cost of administration and
management of the permitting process. The Town shall establish,
by resolution a prorated fee schedule based upon the relative
complexity of the project. The fee schedule may be amended from
time to time by the Town Council by resolution. Notice of such
resolution shall be published no less than fifteen (15) days
prior to adoption. The fee schedule shall be appended to this
ordinance following its adoption and shall be considered to be a
part of this ordinance.
(d) Within thirty (30) days after submission of the
completed Stormwater Management Plan the Town shall approve, with
or without specified conditions or modifications, or reject the
Plan and shall notify the applicant accordingly. If the Town has
not rendered a decision within thirty (30) days after Plan
submission, it shall inform the applicant of the status of the
review process and the anticipated completion date. If the Plan
is rejected or modified, the Town shall state its reasons.
However, it is not the responsibility of the Town or its
designated agent to design an acceptable project.
(e) The Stormwater Management Plan shall not be approved
unless it clearly indicates that the proposed development will
meet the Performance Standards described in Section Eight and the
Design Standards described in Section Nine, except where a
variance has been granted pursuant to Section Five, Subsection
(d), or where off -site management is approved pursuant to Section
Ten.
(f) Inspections: No Stormwater Management Plan may be
approved without adequate provision for inspection of the
property before development activity commences. The applicant
shall arrange with the Town's Building Inspector or his
designated agent for scheduling the following inspections: -
(1) Initial Inspection:
Stormwater Management Plan;
11
Prior to approval of the

(2) Bury Inspection: Prior to burial of any underground '
drainage structure;
(3 ) Erosion Control Inspection: As necessary to ensure
effective control of erosion and sedimentation;
(4) Finish Inspection: When all work including I
installation of all drainage facilities has been completed.
The Town Building Inspector or his designated agent shall inspect
the work and shall either approve it or notify the applicant in
writing in what respects there has been a failure to comply with
the requirements of the approved Stormwater Management Plan. Any
portion of the work which does not comply shall be promptly
corrected by the applicant or the applicant will be subject to
the penalty provisions of Section Thirteen.
(g) Appeals: Any person aggrieved by' the action of any
'
official charged with the enforcement of this Ordinance, as the
result of the disapproval of a properly filed application for a
permit, issuance of a written notice of violation, or an alleged
failure to properly enforce the Ordinance in regard to a specific
application shall have the right to appeal the action to the Town
Board of Commissioners. The appeal shall be filed in writing
,
within twenty (20) days of the date of official transmittal of
the final decision or determination to the applicant, shall state
clearly the grounds on which the appeal is based, and shall be
processed in the manner prescribed for hearing administrative
'
appeals under local and NC State Statutes.
i
SECTION EIGHT: PERFORMANCE STANDARDS
The Stormwater Management Plan must demonstrate the proposed ,
development or activity has been planned and designed and will be
constructed and maintained to meet each of the following
standards:
(a) Ensure that after development, runoff from the site
approximates the rate of flow, volume and timing of runoff that
would have occurred following the same rainfall under existing
conditions and to the extend practicable, predevelopment
conditions, unless runoff is discharged into an Off -site Drainage
Facility as provided in Section Ten:
(b) Maintain the natural hydrodynamic characteristics of the
watershed;
(c) Protect or restore the quality of ground and surface
waters;
12

(d) Ensure that erosion during and after development is
' minimized;
(e) Protect groundwater levels;
' (f) Protect the beneficial functioning of wetlands as areas
for the natural storage of surface waters and the chemical
reduction and assimilation of pollutants;
(g) Prevent increased flooding and damage that results from
improper location, construction and design of structures in areas
which are presently subject to an unacceptable danger of
flooding;
I _- ---- -
(h)
F
L�
(i)
areas;
Prevent or reverse salt water intrusion;
Protect the integrity of natural groundwater recharge
(j) Minimize injury to flora and fauna and adverse impacts
to fish and wildlife habitat;
(k) -Otherwise further -the objectives of this Ordinance.
SECTION NINE: DESIGN STANDARDS
To ensure attainment of the objectives of this Ordinance and
to ensure that performance standards will be met, the design,
construction and maintenance of drainage systems shall be
consistent with the following standards:
(a) Channeling runoff directly into waterbodies shall be
strictly prohibited. Instead, runoff shall be routed through
swales and other systems designed to increase time of
concentration, decrease velocity, increase infiltration, allow
suspended solids to settle, and remove pollutants;
' (b) Natural watercourses shall not be dredged, cleared of
vegetation, deepened, widened, straightened, stabilized or
otherwise altered. Water shall be retained or detained before it
' enters any natural watercourse in order to preserve the natural
hydrodynamics of the watercourse and to prevent siltation or
other pollution;
' (c) The area of land disturbed by development shall be as
small as practicable. Those areas which are not to be disturbed
shall be protected by an adequate barrier from construction
' activity. Whenever possible, natural vegetation shall be
retained and protected;
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(d) No grading, cutting or filling shall be commenced until '
erosion and sedimentation control devices have been installed
between the disturbed area and waterbodies, watercourses and
wetlands; '
(e) Land which has been cleared for development and upon
which construction has not commenced shall be protected from
erosion by appropriate techniques designed to revegetate the
area;
(f) Sediment shall be retained on the site of the I
development;
(g) Wetlands and other waterbodies shall not be used. as- ---- '
sediment traps during development.;
(h) Erosion and sedimentation facilities shall receive
regular maintenance to insure that they continue to function
properly;
(i) Ar-tificial watercourses shall be designed, considering
soil type, so that the velocity of flow is low enough to prevent
erosion;
(j ) Vegetated buffer strips shall be created or, where
practicable, retained in their natural state along the banks of
all watercourses, waterbodies or wetlands. The width of the
buffer shall be sufficient to prevent erosion, trap the sediment
'
in overland runoff, provide access to the waterbody and allow for
periodic flooding without damage to structures;
(k) Intermittent watercourses, such as swales, should be
'
vegetated;
(1) Retention and detention ponds shall be used to retain
,
and detain the increased and accelerated runoff which the
development generates. Water shall be released from detention
ponds into water courses or wetlands at a rate and in a manner
,
approximating the natural flow which would have occurred before
development;
(m) Although the use of wetlands for storing and purifying '
water is encouraged, care must be taken not to overload their
capacity, thereby harming the wetlands and transitional
vegetation. Wetlands should not be damaged by the construction
of detention ponds;
(n) The first one and one-half (1.5) inch of runoff from '
impervious surfaces shall be retained on the site of the
development;
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(o) Runoff from parking lots shall be treated to remove oil
' and sediment before it enters receiving waters;
(p) Detention and retention areas shall be designed so that
' shorelines are sinuous rather than straight and so that length of
shoreline is maximized, thus offering more space for the growth
of littoral vegetation;
(q) The banks of detention and retention areas shall slope
at a gentle grade into the water as a safeguard against drowning,
personal injury or other accidents, to encourage the growth of
vegetation and to allow the alternate flooding and exposure of
areas along the shore as water levels periodically rise and fall;
(r) The -use of drainage facilities and vegetated buffer
zones as open space, recreation and conservation areas shall be
encouraged.
SECTION TEN: OFF -SITE DRAINAGE FACILITIES
(a) The Town of Holly Ridge may allow stormwater runoff that
is otherwise of unacceptable quality or which would be discharged
in volumes or at rates in excess _of those otherwise allowed by
' this Ordinance, to be discharged into drainage facilities off the
site of development if each of the following conditions is met:
' (1) It is not practicable to completely manage runoff on
the -site in a manner that meets the Performance Standards and
Design Standards;
' (2) The off -site drainage facilities and channels
leading to them are designed, constructed and maintained in
accordance with the requirements of this ordinance;
(3) Adequate provision is made for the sharing of
construction and operating costs of the facilities with the
Town. The developer may be required to pay a portion of the
' cost of constructing the facilities as a condition to
receiving approval of the drainage plan;
' (4) Adverse environmental impacts on the site of
development will be minimized.
(b) At request to use off -site drainage facilities and all
information related to the proposed off -site facilities should be
made a part of the developer's Stormwater Management Plan.
Guidelines for the consideration of off -site facility use will be
' defined in the Manual of Surface Water Management Practices.
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SECTION ELEVEN: MANUAL OF STORMWATER MANAGEMENT PRACTICES
,
(a) The Town of Holly Ridge shall compile a manual of
Stormwater Management Practices for the guidance of persons
preparing Stormwater Management Plans, and designing or operating
drainage systems. The Manual shall be updated periodically to
reflect the most current and effective practices and shall be
made available to the public.
'
(b) The Manual shall include guidance and specifications for
the preparation of Stormwater Management Plans. Acceptable
techniques for obtaining, calculating and presenting the
'
information required in the Stormwater Management Plans shall be
described.
(c) The Manual shall include guidance in the selection of
environmentally sound practices for the management of stormwater
and the control of erosion and sediment. Specific techniques and
practices shall be described in detail. The development and use
of techniques which emphasize the use of natural systems shall be
encouraged.
'
(d) The -Manual. shall also establish minimum specifications ----
for the construction of drainage facilities. Construction
specifications shall be established in accordance with current
'
good engineering practices.
(e) The Building Inspector shall submit the Manual and
subsequent revisions of it to the Town Board and Planning Board
'
for review and approval.
SECTION TWELVE: MAINTENANCE
(a) Drainage facilities shall be dedicated to the Town of '
Holly Ridge where they are determined to be appropriately a part
of the Town's maintained system or are unlikely to be adequately
maintained by the developer or owner of the property. '
(b) The systems maintained by the owner shall have adequate
easements to permit the Town to inspect and, if necessary, to
take corrective action should the owner fail to properly maintain '
the system. Before taking corrective action, the Town shall give
the owner written notice of the nature of the existing defects.
If the owner fails within thirty (30) days from the date of '
notice to commencement corrective action or to appeal the matter
to the Town, the Town may take necessary corrective action, the
cost of which shall become a lien on the real property until ,
paid.
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SECTION THIRTEEN: ENFORCEMENT
(a) Nuisance: Any development activity that is commenced
without prior approval of a Stormwater Management Plan or is
conducted contrary to an approved Stormwater Management Plan as
required by this Ordinance, shall be deemed a public nuisance and
may be restrained by injunction or otherwise abated in a manner
provided by law.
(b) Civil and Criminal Penalties: In addition to or as an
alternative to any penalty provided herein or by law, any person
who violates the provisions of this Ordinance shall be punished
by a fine of not less than One Hundred Dollars ($100) nor more
than One Thousand Dollars ($1,000) or by imprisonment in -the
county jail for a period not to exceed sixty (60) days, or _by
both such fine and imprisonment. Such person shall be guilty of
a separate offense for each day during which the violation occurs
or continues.
(c) Any violator may be required to restore land to its
undisturbed condition. In the event that restoration is not
undertaken within a reasonable time after notice, the Town may
take necessary corrective action, the cost of which -shall become
a lien upon the property until paid.
(d) Notice of Violation: When the Town Building Inspector
determines that development activity is not being carried out in
accordance with the requirements of this Ordinance, it shall
issue a.written notice of violation to the owner of the property.
The notice of violation shall contain:
(1) the name and address of the owner or applicant;
(2) the street address when available or a description
of the building structure, or land upon which the violation
is occurring;
(3) a statement specifying the nature of the violation;
(4) a description of the remedial actions necessary to
bring the development activity into compliance with this
Ordinance and a time schedule for completion of such remedial
action
(5) a statement of the penalty or penalties that shall
or may be assessed against the person to whom the notice of
violation is directed;
(6) a statement that the Town' s determination of
violation may be appealed to the Town Board of Commissioners
by filing a written notice of appeal within fifteen (15) days
of service of notice of violation.
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The notice of violation shall be served upon the person(s) to
whom it is directed either personally, in the manner provided for
personal service of notices by the court of local jurisdiction or
by mailing a copy of the notice of violation by certified mail,
postage prepaid, return receipt requested to such person at his
or her last known address.
A notice of violation issued pursuant to this section
constitutes a determination from which an administrative appeal
may be taken to the Town Board of Commissioners.
SECTION FOURTEEN: SEVERABILITY
Each separate provision of this Ordinance is deemed
independent of all other provisions herein so that if any
provision or provisions of this ordinance be declared invalid,
all other provisions thereof shall remain valid and enforceable.
SECTION FIFTEEN: EFFECTIVE DATE
This Ordinance shall become effective on
Adopted this the day of
Mayor
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Reviewed for Legal Consistency:
Town Attorney
Date
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