West Onslow Beach Carrying Capacity Study-1988

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EXECUTIVE SUMMARY
1988 WEST ONSLOW BEACH
CARRYING CAPACITY STUDY
The West Onslow Beach Carrying Capacity Study has been prepared as
a follow-up.to the 1986 Coastal Area Management Act Land Use Plan prepared
by Onslow County. The study is.intended to give local officials and County
citizens information on the current direction of growth of West Onslow Beach
and the impact this growth might have on current infrastructure and the
beach environment. The study is also intended to provide information on
current ordinances and policies that have'a direct impact on the quantity
and quality of future development.
After a review ofcurrentinfrastructure', including water, sewer, roads
and solid waste disposal, in light of development now taking -place or
planned, it is apparent that there exists a need for comprehensive growth
management planning at the County level to prepare for current and future
growth. In discussions with County department heads, it is apparent that
each department head is aware of the need to plan for the growth that is
going to take place on the beach.`
In addition, there is a need to review current Beach Area Development
Policy, current zoning patterns and zoning restrictions and their impact
on current and future development.
Beginning on page 25 of the study, there is a study summary, with
recommendations beginning on page'28 that address the sewer system, roads
and County zoning. -

TABLE OF CONTENTS
Page
Introduction
1
Current West Onslow Beach. Development Policy
1
Existing Land Use Controls and Facilities
4
Conservation Zoned Land Area
4
Existing.Developed Areas, North of NC 210 Bridge
5
Existing Developed Areas South of NC 210 Bridge
5
Land Available for Development North of NC 210 Bridge
6
Land Available for Development South of NC 210 Bridge.
8
Potential Residential Population
9
Annual Erosion Rates
12
Bridge and Highway System
13
Sewer System
15
Water System
15
Soils and Septic Tank Use
16
Parks and Recreation Facilities
17
Solid Waste Disposal
20
Fire Fighting Capabilities
r
21
Beach Evacuation
22
Impact of Current Beach Development Policy on Future
Beach Development
22
Need for Comprehensive Study of Future Transportation
Needs
24
Comprehensive Growth Management Needed
24
Carrying Capacity Summary
25
Plan Recommendations
J
28

a
Tables
Table
I
Acreage Available for Lower Density Development
North of Bridge
7
Table
II
Acreage Available for Higher Density Development
North of Bridge
7
Table
III
Acreage Available for Lower Density Development
South of Bridge
8
Table
IV
Acreage.Available for Higher Density Development
South of Bridge
9
Table
V
Total Acreage Available for Development by
Zone and Planning Area
10:
Table
VI
Future Development Potential by Zoning Type
11=
Table
VII
Current Residential Development Density
Permitted by Zoning Classification
12
Maps
Map 1
Current Beach Development Policy North of Bridge
Map_2
Current Beach Development Policy South of Bridge
Map 3
Conservation Zoned Land Area North of Bridge
Map 4
Conservation Zoned Land Area South of Bridge.
Map 5
Existing Developed Areas North of Bridge
Map 6
Existing Developed Areas South of Bridge
Map 7
Land Available for Development North of Bridge
Map 8
Land Available for Development South of Bridge
Map 9
Beach Erosion Rates
Map 10
Bridge and Highway System.North End of West Onslow.Beach
Map 11
Highway System at South End of West Onslow Beach
Map 12
Sewer System North of Bridge
Map 13
Sewer System South of Bridge

I.
include the R-8 and R-5 Residential Districts as defined in the Onslow County
Zoning Ordinance, with the,RA, R-40, R-20, R-15 and R-10 Residential Districts
making up the Lower Density Development areas. Currently the Zoning Ordinance
has no height restrictions in.the R-8 and R-5 zones, with a minimum of 3,000
square feet of land area per unit requirement in the R-5 zone and 4,000 square
feet per unit minimum in the R-8 zone. In addition to permitted densities in
the Zoning Ordinance, the County has recently amended the Zoning Ordinance in
an effort to prevent overcrowding of taller buildings on the beach front.
Specifically, the ordinance reads, "In the R-8 and R-5 Districts, any building
with a height of 50 feet or more shall provide a minimum side, front and rear
yard equivalent to the minimums required.by the Zoning Ordinance plus 1.2 feet =
for each one foot, or fraction thereof, of building height above 50 feet for
each side and rear yard,.'and an additional setback equivalent to .5 foot for
each one foot, or fraction thereof, of building height above 50 feet for the
front yard." The ordinance further states that, "attachments to such buildings
not designed for residential purposes, such as, but not,limited to, covered
walkways, entrances, covered swimming pools and dining areas, may extend to
the minimum setback as required by the Zoning Ordinanceprovided such attach-
ments do not exceed 35 feet-'in,building height.','
As shown on the Current Beach Development Policy Map (Map l),,much of
the beach, front area north of the NC 210 bridge is currently undeveloped with
potential for higher density development due to the County's current policy '
to encourage higher density development on the beach side of the beach road,
SR 1568, contingent on meeting all CAMA setback requirements. As reflected -
on Map 1, much.of this beach front area consists of a very narrow strip of
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land that currently might not be suitable for development; however,'since
i
plans are proceeding to realign a. portion of this road, much more land area
on the beach side of the road will be available for higher density development.
As the road realignment proceeds, County officials can anticipate a'sharp
increase in the number of requests to allow higher density development on
the beach front as has happened with the recent approval of twin 15-story
buildings. Map 1 shows the sound side of the beach road, SR 1568, as an
area where lower density development will be encouraged in an effort to pro-
tect this more environmentally -sensitive area from the impact of additional
storm water runoff and other.impacts associated with higher density residential
and commercial development. Because this area is adjacent to Stump Sound,
which is being considered for designation as an outstanding water resource,
it is important that density remain low in this area as County policy now
calls for. A lower density of development on the sound side will help
protect this productive shellfish and finfish area as well as designated
primary nursery areas.
Map 2 also reflects a policy of higher density development along .the
beach side of the beach road, NC 210, and lower density development on the
sound side. The map also reflects County policy to encourage lower density
development at the southern end of the beach in areas where lower density
development already exists.
On both Map.l and 2 all areas not shown as potential High D6nsity.or
Lower Density Development areas are either already developed or in a Conser-
vation Zone. (See Maps 3, 4, 5 and 6)
3

County policy is to'encourage lower density development in or adjacent to
i
existing lower density development in order to maintain the character of -this
area, with higher density development along the beach front in areas where
development has not yet taken place. For example, in the area adjacent
to the new Island Villas, higher density development would be appropriate
under current County policy if suitable zoning is available or can be obtained
by request for rezoning.
In preparing this Carrying'Capacity Study, current development and
zoning patterns have been used. Obviously, as rezoning is requested and
approved for higher densities such as R-8 and R-5, the potential development
densities will increase.
Land Available for Development North of NC 210 Bridge (Map 7)
This map shows a substantial amount of land available for development
north of the NC 210 bridge. A review of this land by zoning classification
and as reflected in Table I shows a total of approximately 103.9 acres
available for lower density residential development, which would include
zones RA, R-20, R-15 and R-10 Table II reflects the availability of
higher density property and shows no R-5 or R-8 land on the beach side of
NC 1568 and 43.4 acres of R-5 and 1.4 acres of R-8 zoned land on the sound
side of NC 1568. This current zoning.pattern is not consistent with -the
beach development policy discussed earlier since much of the high density
zoned vacant land is located on the sound side of the beach road. Because
this land is already zoned to permit a higher density of development, it
may not be feasible to lower the density without property owner cooperation.
See Appendix for Zoning Ordinance lot size and setback requirements.
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However, it may be possible to change the zoning on -the sound side area of
the beach road if the affected property owners are in agreement with such a
change. Even without such zoning changes, local officials can be consistent
with current beach development policy by not approving any additional
requests for R-8 or R-5 zoning on the sound side of NC 1568.
Table I
1988 Carrying Capacity Study
Acreage Available for Lower Density -Development
North of Bridge
Zone Acres
RA 18.7
R-20 46.6
R-15 6.3
R-10 32.3
Total Acres 103.9
Table II
Acreage Available for Higher Density Development
North of Bridge
Beach Side Sound Side
Zone Acres Zone Acres
R-5 0 R-5 43.4
-R-8 0 R-8 1.4
Total Acres 0 44.8
Source: Acreage on both tables tabulated from Onslow County Zoning Map
by Howard T. Capps and Associates.
7

Land Available for Development South of NC 210 Bridge (Map 8)
As discussed earlier, this portion of the beach contains more existing
development with less land area available for future development. Table III
shows a total of approximately'79.8 acres available for lower density
residential development which includes zones R-20, R-15 and R-10. Table IV
reflects the availability of higher density property with approximately
41.8 acres of R-5 land and 1.7 acres of R-8 land on the beach side of the
beach road. This table also reflects 25.2 acresofR-5 land and 4.0 acres
of R-8 land on the sound side of the beach road. Like the area north of
the bridge, much of the undeveloped land zoned for higher density develop-
ment is located on the sound side of the beach road or in the existing lower
density developed areas at the southern end of the beach.- In both cases,
this zoning pattern is currently inconsistent.with beach development policy
and the same recommendations as discussed for the area north of the bridge
would apply.
Table III
Acreage Available for Lower Density Development
South of Bridge
Zone
'Acres
R-20
- 22.0
R-15
29.8
R-10
28.0
Total Acres 79.8

Table IV
Acreage Available for Higher Density Development
South of Bridge
Beach Side Sound Side
Zone Acres Zone Acres
R-5 41.8 R-5 25.2
R-8 1.7 R-8 4.0
Total Acres 43.5 29.2
Note: Of the total acreage shown above, 22.8 acres
on the beach side and all of the acreage on
the sound side represent high density zoned
land available in area where current policy
calls for lower density development.
Source: Acreage tabulated from Onslow County Zoning Map by
Howard T. Capps and Associates
Potential Residential Population
An analysis of current land availability and residential density.per
mitted by the Zoning�Ordinance shows an estimated potential beach population
of 12,704 to 16,155 people. This is based on 2,068 existing units in
areas 1 through 6 and 753 units in areas 7 through ll* as discussed in the
1987 West Onslow Beach Land Use `Study prepared by the Planning Department.
Using the 1,560 to 2,750 units reflected in Table VI multiplied by 2.9
persons per unit, we have calculated this potential population.. As discussed
earlier, this would be based on current zoning patterns and permitted
density and could increase substantially if higher density rezoning is
requested and approved. Based on these projected densities, the next,question
Areas l through 6 and 7 through 11 refer to planning areas used in 1987
West Onslow Beach Land Use Study.
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is how would this potential density impact on facilities and the.quality of,
life on West Onslow Beach.
Table V reflects the 'acreage available for development by.zoning
classification and planning area used by the Onslow County.Planning Department
in their 1987 West Onslow Beach Land Use Study. Table VI reflects the
approximate acreage currently vacant and available for development. This
table also shows the lowest and highest densities permitted by zoning
classification. Specifically, if all residential zoned vacant land was
Table V
1988 Carrying Capacity Study
Onslow County Zoning
Zoning
Classifi- Total Acreage Available for D"elopment by Zone and Planning 4rea
cation 1 2 3 4 5 6 7 8 9 10 11 Total
RA
_
_
18.7
-
_
_
_
18.7
P-4u
-
-
_
R-20
- 12.4
-
4.0
-
5.6
-
35.5
1.3
-
9.8
68.6
R-15
-
29.8
6.3
36.1
R-10
15.6
5.8
6.6
-
2.6
15.9
8.1
5.7
60.3
R-8
1.7
-
-
4.0
2.0
7.7
R-5
- 44.2
-
4.4
16.3
29.2
15.3
1.0
-
-110.4
Undersized
Lot
-
.7
.5
-
-
-
-
_
1.5
MHP
- -
.6
_
-
-
-
-
-
.6
His
5
2.0
_
_
_
_
_
2.5
B-1
- 1.6
14.6
-
-
-
-
-
-
16.2
B-2
-
-
-
4.9
- 4.9
B-3
-
-
2.5
15.5
-
2.3
-
0.1
-
26.4
M-2
Con.-D
• •
•
•
a
•
•
•
•
i
Total
- 74.3
10.8
15.8
17.1
71.2
47.9
55.7
24.5
16.2
20.4
353.9
Note: Areas 1 through 6 are south of bridge, 7 through 11 are north of bridge. Planninareas_
areas refer to study areas used in 1987 West Onslow Beach Lend Use Study conducted'
by Onslow County Planning staff.
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developed meeting the single family requirements for land area;, this acreage
would result `in approximately 1,560 additional residential units. If this,
land area is developed at its highest permitted density, approximately 2,750
additional residential units would .result. Table VII reflects the units per
acre for each residential zoning classification which varies from 3'acres
per unit in the RA zone to approximately 14 units per acre.in the R-5 zone
This density of development represents build -out development based on current
zoning requirements.
Table VI
1988 Carrying Capacity Study
Future Development Potential
by Zoning Type
Permitted Permitted
Residential Approximate Acreage by Lower Density Higher Density
Zoning Classification Zoning Classification Dwelling UnitsDwelling Units
RA 18.7' 12 0
R-40 0 0 0
R-20 68.6 150 300
R-15 36.1 105 210
R-10 60.3 263 526
R-8 7.7 42 84
R-5 110.4 961 19603
MHP .6 5 5
MHS 2.5 22 22
Number of potential residen-
tial units.on currently
undeveloped land 1,560 2,750
Non -Residential
Zoning Classification Approximate Acreage Potential Sites
`B-1 16.2 88 Highway Business development sites
B=2 4.9 27 General Business developments
B-3 26.1 26 or more Marina Business developments
M-1 p 0
M-2 0 0
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Table VII
Current Residential Development Density
Permitted by Zoning Classification
Zoning Type Units per Acre`
RA 3 acres per unit "
R-40 1.08
R-20 4.`4
R-15 5.8
R-10 8.7
R-8 10.9 -
R-5 14.0
*All other zoning types are.units per acre
Source: Howard T. Capps and Associates
Annual Erosion Rates (Map 9)
One major _natural occurrance having a direct impact on future development
along West Onslow Beach is the annual erosion rate. As illustrated on Map 9,;
one area south of the NC 210 bridge and two areas north of the bridge are
experiencing substantial erosion rates. The area south of the bridge has an
average erosion rate of approximately 2.5 feet per year. The :two areas north
of the NC 210 bridge are experiencing erosion at the rate of 2.25 feet and
3.5 feet per year. Obviously, if this erosion rate continues over a long
period of time, for example 10 years, the land area lost to erosion would
range from 25 to 35 feet of beach front. With current County policy to
allow high rise buildings on the beach front with no limit on height, the
combination of high erosion.rates and high rise buildings.could be devastating.
Because state regulations do not permitseawalls to protect buildings from.
the ocean's encroachment, protecting high rise buildings in the future can
12

be accomplished only through beach renourishment, which is.a very expensive
' undertaking and a temporary solution at best. Considering current ocean
erosion rates, County officials need to look very carefully at current
zoning setbacks and lack ofheight limitations on buildings. Specifically,
the R-8 zone presently requires only a 15' rear yard setback, with the R-5
zone requiring only a 10' rear yard setback in addition to any CAMA regula-
tions. Even with the:new 1.2 feet of additional yard setback now required
for any building over 50 feet in height, it.would not take many years for
'such buildings to become vulnerable to the ocean through beach front erosion.
In addition to high rise buildings on the ocean front being vulnerable
to beach erosion, portions of SR 1568 have already experienced overwash.
This overwash is particularly.troublesome in the fact that the realignment
of. SR 1568 now being implemented has not addressed the sections of existing
SR 1568 that are subject to overwash
Bridge and Highway System (Maps 10 and 11)
The' -NC 210 bridge over the Intracoastal Waterway has a design capacity
of 12,000 vehicles per day in each direction based on information from the
Department of Transporation Bridge Replacement Engineer. The drawbridge
at Surf City is very narrow and can only carry two—way traffic if not being
crossed by a truck, at which time it is only one way. Based on information
also obtained from the.Department of Transportation,' the capacity of the
Surf City bridge could be determined only by a detailed analysis of how
frequentlythe bridge opens per day and how that affects traffic. Highway
NC 210 from the bridge south to the Pender County line has a typical 20' to
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24' section with a 60' to 100' wide right-of-way. State Road 1568 from the
bridge north has a typical section of 18' and a 60' right-of-way. According
to information provided by the Department of Transportation in Raleigh, .
roads like NC 210 which carry an average traffic flow (level of service C)
have a carrying capacity of approximately'7,000 to 9,000 vehicles per day.
Since NC 210 has a 20' to 24' road section, it can be assumed that SR 1568,
with an 18' section, could carry somewhat less than this volume of traffic _
per, day. With a potential density of from 12,704 to 16,155 people, and
assuming that each car carried the 2.9 persons per household, it would be
necessary to evacuate 4,381 to 5,571 cars from the beach if a major storm
threatened the beach during the peak season. On the current road system
with a carrying capacity of 7,000 to 9,000 cars per day for NC 210, it would
take approximately 15 to`19 hours to evacuate the beach area. This is also
assuming that no overwash occurs that would prevent evacuation from the
beach in the event.of a storm emergency.As the beach population continues
to.increase, it will become vitally important that an adequate road system
is available and one that is not as vulnerable to overwash. With County
policy to encourage higher density development -on the beach,side of the beach
-road, the relocation of this road now in process would help insure a safer
route for a portion of this area at the northern end of the beach. However,
as discussed earlier, the most vulnerable section of existing SR 1568 near
Galleon Bay has not been included in plans for realignment, which leaves the
northern end of the beach vulnerable to overwash and thereby a lack of
evacuation route during a major storm.
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i Sewer System (Maps 12 and 13)
Topsail Water and Sewer, Inc., provides sewer service to West 0nslow
Beach with a 12" dine north of the NC 210 bridge and a 12" line south
of the bridge to 13th Street.The company.presently has plans to extend
a 16" force main from 13th Street to Scotch Bonnet, which is the limit of
their service area. The system has a current capacity of'877,000 gpd with
approximately 100,000 gpd not allocated to,new"development.
The system -owner is presently having plans prepared for review by the
Division;of Environmental Management in mid-1989. Plans would reflect
expansion of the spray field capacity to 1.3 mgpd which would equal the
present lagoon capacity. Based on information from the system owner, their
long-range goal is to have,a capacity of 6 mgpd. Although there have been
regulatory problems with the system in the past, having a sewer system in
place provides a means to remove effluence from the environmentally -sensitive
beach area -and reduce or eliminate the need for individual septic tanks which
can cause environmental damage if not properly installed and maintained.
Water System (Maps 14 and 15)
The .water system is owned and operated by.Onslow County. The system
consists of an 8" water main serving the north end of the beach with a 10"
`water main serving the area south.of the NC 210 bridge. As discussed in the
1986 Land Use Plan, the County water system has a design capacity of 2.7 mgd
of potable water using six existing well sites pumping 12 hours per day.
The County water system;is presently working at'or near capacity with
bottlenecks in the distribution system in high demand areas of the County.
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A report prepared by Black and Veach recommends an increase in the number of
wells to increase pumping capacity. Based on projected development in the
foreseeable future, the existing 8" and 10".water mains will be adequate to
serve the beach area. However, as the beach continues to grow the County
needs to upgrade.the system to provide adequate water pressure for fire
protection in addition to providing potable water with ;30:lbs. of static
pressure. Based on discussions with the Water System Director, there have
been discussions of upgrading lines and storage tanks but no firm plans.
Because current and future development will impact on the current water
system, the County may want to give consideration to establishing impact
fees on future development. to help pay the cost of system expansion. Presently
developers of high rise buildings must meet safety requirements of the State
Building Code through auxiliary storage or pressure pumps.
Soils and Septic Tank Use
The.County Health Department has responsibility for issuing permits
for septic tank use. Based on information fro the Health Department, they
will not approve septic tanks on dredge fill or organic soils. A decision
,on septic tank use is based on soil testing or soil texture, distance to
well, etc., with lot size being determined by subdivision and zoning
requirements.- Current County"policy on septic tanks is to permit their use
if they meet all applicable county, state and federal regulations. A review
of the detail soils report for Onslow County revealed that West Onslow Beach
has incomplete information on soil types. The County index map calls for
quad sheets C-9, D-91 E-8, E-9 and F-7. Map C-9 has no soils identified
16

and sheet E-9 was not available. However, based on.the information that was
available, all soils located in the beach area have severe problems for
septic tank use. Specifically, the following:
Symbol Soil Name Septic Tank Absorption
Bo Bohicket.Series Severe problems due to flooding, ponding
and slow,perc.
Co Corolla Fine Sand Severe problems due to wetness and poor
filter.
Dc Duckston Fine Sand Severe problems due to flooding, wetness
and poor filter'.
Ne Newhan Severe problems due to poor filter and slope
In addition.to these soils, there were several other soils identified
on the map of the beach area with symbols for which there was no reference
in the soil report text, specifically`Bol, Uc, Us, and Nd. The local Soil
Conservation Office in Jacksonville was-also.unable to identify these symbols.
Because of the environmentally sensitive character of West Onslow
Beach and the availability of a sewersystem, septic tank use on the beach
should be discouraged. Theimpact of soil types on future construction will
remain the responsibility of the developer on a project -by -project basis.
Parks and Recreation Facilities
Onslow County citizens and visitors are fortunate in.having three
beach access areas available for their use. Sites 1 and 2 have gates to
control access and are open during the following times:
Fall/Winter (October -March). Open 9 AM, Closed 5 PM
Spring/Summer_;(April-September)-Open 9 AM, Closed 11 PM
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t
All park areas are patrolled by two park rangers who are also law ,
officers. Onslow County is one of.only two counties with law officers as
park rangers.' The County also has one uniformed park attendant during the
summer season to clean areas, maintain buildings, etc. The Parks and
Recreation Director has found that having two full-time park rangers and
one part-time attendant has reduced problems of litter, noise or any other
disturbances.
Onslow County Public Beach Park #1 was first opened in 1984. The
parking lot will accommodate 65 cars with access to the beach by way of a
walkway extending over the dune. The facility also includes an attractive
pavilion with lavatories for men and women with handicapped access. The
facility also has an outdoor shower and drinking fountain. Based on recent_
information from the Parks and Recreation Department, the following attendance
was recorded for Sites #1, #2, and #3.
Location People
Site #1 4,672
Site #2 17,244
Site #3 3,058
Source: County Recreation Department Annual Report (Note: Count is
taken only when staff is on.site,.which is approximately one
visit per week. - Figures represent partial attendance.)
Beach Park #2 is substantially larger than park rl and one year newer.
This site-occupies'400 feet of beach front and includes the sound side of
NC`210. Parking.space is provided on both sides of the highway and will
accommodate approxiamtely 165 cars with plans to expand parking by an
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}
additional 50 cars through a pending beach access grant. An elevated wood
pavilion and observation deck are also available with restroom facilities
accessible for the handicapped. Showers, drinking fountain and pay phone
are also provided. This site also has a nature trail and wetland area with
additional County -owned land adjacent to the site.
Beach Park #3 consists of 700 feet fronting the New River Inlet.
The site contains space to park approximately 40-cars. This site is •used
for vehicular access to the beach.
Beach Access #4 has been donated to the state for a major beach access
area with parking for up to 500 cars.
With the three County sites and one yet undeveloped state site, Onslow
County.is ahead of most other coastal communities in providing adequate and
attractive beach access areas, primarily through donations of land from
private land owners and the use of CAMA funds for development of facilities.
Although the County is ahead of most coastal communities, it should continue
to plan on and develop additional public access areas while property is
still available.
If the Parks and Recreation Department established a plan of action
for the next five to.20 year period for.acquisition and development of
additional sites, the County would continue to stay ahead of other areas
in providing adequate beach access.. Also, if the County revised'current
Subdivision Ordinance requirements and established a payment in lieu of
dedication of a 10' wide access strip, the County could develop a fund for
use by the Parks and Recreation Department in purchasing and improving
future beach and estuarine access areas.
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