2010-2011 Final ReportCOASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
NEW HANOVER COUNTY WATER QUALITY MONITORING PROGRAM
2010-2011
FINAL REPORT
Prepared by:
Coastal Planning & Engineering of North Carolina, Inc.
Marine Scientist: Brad Rosov, M.Sc.
Prepared For:
New Hanover County, North Carolina
Recommended Citation: Rosov, B., 2011. New Hanover County Water Quality Monitoring
Program: 2010-2011 Final Report. New Hanover County, North Carolina: Coastal Planning &
Engineering of North Carolina, Inc. 55p.
June 2011
i
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
EXECUTIVE SUMMARY
This report represents the results of the New Hanover County Water Quality Monitoring
Program between June 2010 and May 2011. Nineteen (19) monitoring stations within seven (7)
creeks in New Hanover County were monitored on a monthly basis for physical, chemical, and
biological parameters of water quality. The results presented in this report are described from a
watershed perspective.
In order to provide a quick-glance assessment of the water quality within a particular sampling
station and watershed, a rating system has been established for a number of parameters. This
quantitative system assigns a rating of “GOOD”, “FAIR”, or “POOR” to a sampling station
depending on the percentage of samples exceeding the State standard for dissolved oxygen,
turbidity, chlorophyll-a, Enterococci, and fecal coliform bacteria. If the recorded value of a
parameter exceeds the State standard less than 10% of the times sampled, the station will receive
a “GOOD” rating for the parameter. A “FAIR” rating is assigned when a parameter exceeds the
State standard 11-25% of the times sampled. Parameters measured that exceed the State
standard more than 25% of the sampling times are given a “POOR” rating.
As displayed in the tables below, turbidity and chlorophyll-a were determined to be “good”
within all watersheds throughout the study period. Dissolved oxygen varied considerably
between watersheds and within sites. Specifically, Barnards Creek, Lords Creek, Motts Creek,
and Smith Creek were deemed to be “good” while Futch Creek contained “fair” levels of
dissolved oxygen. Both Pages Creek and Prince Georges Creek were rated as “poor" for
dissolved oxygen. Generally, Enterococci was problematic within a number of these watersheds.
Four of the watersheds were rated as “poor” including Barnards Creek, Motts Creek, Prince
Georges Creek, and Smith Creek. Pages Creek rated “fair” while Futch Creek and Lords Creek
were deemed “good”. Fecal coliform, another indicator of bacterial contamination, was assessed
monthly within Pages Creek and Futch Creek. These creeks generally exceeded the State
shellfish standard for fecal coliform bacteria resulting in “poor ratings”.
Ratings by Watershed
Parameter Barnards
Creek
Futch
Creek
Lords
Creek
Motts
Creek
Pages
Creek
Prince
Georges
Creek
Smith
Creek
Turbidity GOOD GOOD GOOD GOOD GOOD GOOD GOOD
Dissolved Oxygen GOOD FAIR GOOD GOOD POOR POOR GOOD
Chlorophyll-a GOOD GOOD GOOD GOOD GOOD GOOD GOOD
Enterococci POOR GOOD GOOD POOR FAIR POOR POOR
Fecal Coliform N/A POOR N/A N/A POOR N/A N/A
Long Term Trends
Using data collected on a monthly basis since at least November 2007, the long term trends of
select water quality monitoring parameters were assessed in this report as well. In general,
dissolved oxygen, turbidity, and chlorophyll-a levels oscillate on a seasonal basis. Water
ii
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
quality, as it relates to these parameters, generally decreases during the warmer months when the
water temperatures increase. However, during the cooler months, when the water temperature
drops, these parameters improve.
Since 2007, dissolved oxygen levels exceeded the State standard within surface samples 30%,
23%, and 20% of the time within Prince Georges Creek, Pages Creek, and Futch Creek,
respectively. Dissolved oxygen levels were better within Smith Creek, Motts Creek, and Lords
Creek where the State standard was breached 8%, 5%, and 2%, respectively. None of the
observations within Barnards Creek exceeded the dissolved oxygen standard.
Enterococci bacteria has been a chronic problem within several of the creeks monitored in this
study. Since November 2007, samples collected within Motts Creek, Barnards Creek, and
Smith Creek have exceeded the State standard for Enterococci 36%, 35%, and 34% of the time,
respectively. Both Prince Georges Creek and Pages Creek exceeded this standard 24% of the
time. Relatively low Enterococci bacteria counts have been observed within Lords Creek and
Futch Creek where the State standard has been exceeded within 6% and 2% of the samples,
respectively.
Turbidity and chlorophyll-a were not problematic in any creeks. Of the 817 samples collected
since November 2007, only 11 contained chlorophyll-a concentrations higher than the State
standard of 40 ug/L. Five of these were in Pages Creek and 3 were in Smith Creek and Lords
Creek. The turbidity standard was only breached 3 times in total; 2 from within Smith Creek and
1 within Pages Creek.
iii
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
NEW HANOVER COUNTY WATER QUALITY MONITORING PROGRAM
FINAL REPORT
Table of Contents
1.0 Introduction .................................................................................................................................1
1.1 Parameters .............................................................................................................................4
1.2 Standards ...............................................................................................................................6
2.0 Methods.......................................................................................................................................8
2.1 Physical Parameters ..............................................................................................................9
2.2 Chemical and Biological Parameters ....................................................................................9
3.0 Results .........................................................................................................................................9
3.1 Rating System .......................................................................................................................9
3.2 Barnards Creek .......................................................................................................................10
3.3 Futch Creek ...........................................................................................................................13
3.4 Lords Creek ...........................................................................................................................17
3.5 Motts Creek ...........................................................................................................................20
3.6 Pages Creek ...........................................................................................................................24
3.7 Prince Georges ......................................................................................................................29
3.8 Smith Creek ..........................................................................................................................33
3.9 Comprehensive Rating by Watershed ...................................................................................38
3.10 Long Term Trends ..............................................................................................................39
3.10.1 Dissolved Oxygen
3.10.2 Turbidity
3.10.3 Chlorophyll-a
3.10.4 Enterococci
4.0 Discussion ...................................................................................................................................50
5.0 Literature Cited ...........................................................................................................................54
List of Figures
Figure No.
1 Map of New Hanover County and watersheds included in this study ...................................3
2 Water Quality Sites within the Barnards Creek Watershed ...................................................11
3 Dissolved Oxygen at BC-CBR ..............................................................................................12
4 Enterococci at BC-CBR ........................................................................................................12
5 Water Quality Sites with the Futch Creek Watershed ..................................................................14
6 Dissolved Oxygen at FC-4 .....................................................................................................15
7 Dissolved Oxygen at FC-6 .....................................................................................................15
8 Dissolved Oxygen at FC-13 ................................................................................................... 15
9 Dissolved Oxygen at FC-FOY ............................................................................................... 16
10 Enterococci and Fecal Coliform at FC-4 ............................................................................... 16
11 Enterococci and Fecal Coliform at FC-6 ............................................................................... 16
12 Enterococci and Fecal Coliform at FC-13 ............................................................................. 17
iv
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
NEW HANOVER COUNTY WATER QUALITY MONITORING PROGRAM
FINAL REPORT
Table of Contents
13 Enterococci and Fecal Coliform at FC-FOY .....................................................................17
14 Water Quality Site within the Lords Creek Watershed .....................................................19
15 Dissolved Oxygen at LC-RR .............................................................................................20
16 Enterococci Levels at LC-RR ............................................................................................20
17 Water Quality Sites within the Motts Creek Watershed ....................................................22
18 Dissolved Oxygen at MOT-CBR .......................................................................................23
19 Dissolved Oxygen at MOT-ND .........................................................................................23
20 Enterococci at MOT-CBR .................................................................................................23
21 Enterococci at MOT-ND ...................................................................................................24
22 Water Quality Sites within the Pages Creek Watershed ....................................................26
23 Dissolved Oxygen at PC-BDDS ........................................................................................27
24 Dissolved Oxygen at PC-BDUS ........................................................................................27
25 Dissolved Oxygen at PC-M ...............................................................................................27
26 Enterococci and Fecal Coliform at PC-BDDS ..................................................................28
27 Enterococci and Fecal Coliform at PC-BDUS ..................................................................28
28 Enterococci and Fecal Coliform at PC-M .........................................................................28
29 Water Quality Sites within the Prince Georges Creek Watershed .....................................30
30 Dissolved Oxygen at PG-CH .............................................................................................31
31 Dissolved Oxygen at PG-ML.............................................................................................31
32 Dissolved Oxygen at PG-NC .............................................................................................31
33 Enterococci at PG-CH .......................................................................................................32
34 Enterococci and Fecal Coliform at PG-ML .......................................................................32
35 Enterococci at PG-NC .......................................................................................................32
36 Water Quality Sites within the Smith Creek Watershed ....................................................34
37 Dissolved Oxygen at SC-23 ...............................................................................................35
38 Dissolved Oxygen at SC-CD .............................................................................................35
39 Dissolved Oxygen at SC-CH .............................................................................................35
40 Dissolved Oxygen at SC-GR .............................................................................................36
41 Dissolved Oxygen at SC-NK .............................................................................................36
42 Enterococci at SC-23 .........................................................................................................36
43 Enterococci at SC-CD ........................................................................................................37
44 Enterococci at SC-CH ........................................................................................................37
45 Enterococci at SC-GR ........................................................................................................37
46 Enterococci at SC-NK .......................................................................................................38
47 Long term surface dissolved oxygen data within Barnards Creek ....................................40
48 Long term surface dissolved oxygen data within Futch Creek ..........................................40
49 Long term surface dissolved oxygen data within Lords Creek ..........................................40
50 Long term surface dissolved oxygen data within Motts Creek ..........................................41
51 Long term surface dissolved oxygen data within Pages Creek ..........................................41
52 Long term surface dissolved oxygen data within Prince Georges Creek ..........................41
v
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
NEW HANOVER COUNTY WATER QUALITY MONITORING PROGRAM
FINAL REPORT
Table of Contents
53 Long term surface dissolved oxygen data within Smith Creek .........................................42
54 Long term surface turbidity data within Barnards Creek ...................................................42
55 Long term surface turbidity data within Futch Creek ........................................................43
56 Long term surface turbidity data within Lords Creek ........................................................43
57 Long term surface turbidity data within Motts Creek ........................................................43
58 Long term surface turbidity data within Pages Creek ........................................................44
59 Long term surface turbidity data within Prince Georges Creek ........................................44
60 Long term surface turbidity data within Smith Creek .......................................................44
61 Long term chlorophyll-a data within Barnards Creek .......................................................45
62 Long term chlorophyll-a data within Futch Creek ............................................................45
63 Long term chlorophyll-a data within Lords Creek ............................................................46
64 Long term chlorophyll-a data within Motts Creek ............................................................46
65 Long term chlorophyll-a data within Pages Creek ............................................................46
66 Long term chlorophyll-a data within Prince Georges Creek .............................................47
67 Long term chlorophyll-a data within Smith Creek ............................................................47
68 Long term Enterococci data within Barnards Creek ..........................................................48
69 Long term Enterococci data within Futch Creek ...............................................................48
70 Long term Enterococci data within Lords Creek ...............................................................48
71 Long term Enterococci data within Motts Creek ...............................................................49
72 Long term Enterococci data within Pages Creek ...............................................................49
73 Long term Enterococci data within Prince Georges Creek ...............................................49
74 Long term Enterococci data within Smith Creek ..............................................................50
List of Tables
Table No.
1 List of Sampling Sites ............................................................................................................2
2 North Carolina Water Quality Standards ...............................................................................7
3 Single sample standards for Enterococci as determined by the US EPA ..............................7
4 Single sample standards for Enterococci as determined by the NC DENR Recreational
Water Quality Program ..........................................................................................................8
5 Proposed Tier Classification for New Hanover County Water Quality Monitoring
Sampling Sites .......................................................................................................................8
6 Mean values of select parameters from Barnards Creek .......................................................11
7 Ratings of parameters within sampling stations within Barnards Creek ...............................12
8 Mean values of select parameters from Futch Creek .............................................................14
9 Ratings of parameters within sampling stations within Futch Creek ....................................17
vi
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
NEW HANOVER COUNTY WATER QUALITY MONITORING PROGRAM
FINAL REPORT
Table of Contents
10 Mean values of select parameters from Lords Creek .............................................................19
11 Ratings of parameters within sampling stations within Lords Creek ....................................20
12 Mean values of select parameters from Motts Creek .............................................................22
13 Ratings of parameters within sampling stations within Motts Creek ....................................24
14 Mean values of select parameters from Pages Creek .............................................................26
15 Ratings of parameters within sampling stations within Pages Creek ....................................29
16 Mean values of select parameters from Prince Georges Creek .............................................30
17 Ratings of parameters within sampling stations within Prince Georges Creek .....................33
18 Mean values of select parameters from Smith Creek ............................................................34
19 Ratings of parameters within sampling stations within Smith Creek ....................................38
20 Ratings of parameters within each watershed ........................................................................38
List of Appendices
Appendix No.
A Photographs of Sampling Sites
B Raw Data
1
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
1.0 INTRODUCTION
The creeks in New Hanover County, North Carolina provide a wide range of recreational
activities for thousands of local citizens and visiting tourists each year. Tidal creeks are rich
areas in terms of aquatic, terrestrial and avian wildlife and can support complex food webs
(Odum et al, 1984; Kwak and Zedle, 1997). Protection of the water quality within these creeks is
a high priority for New Hanover County. As growth and development continue within the City
of Wilmington and the County, water quality has been increasingly threatened due to many
factors including aging infrastructure, increased impervious surface area and subsequent
stormwater runoff. To address these issues, the County has administered a long-standing water
quality monitoring program since 1993 designed to assess the water quality within the creeks
located within the County.
Coastal Planning & Engineering of North Carolina, Inc. began monitoring seven (7) tidal creeks
within New Hanover County on a monthly basis in November 2007. The information presented
in this report represents the results of this monitoring between the months of June 2010 and May
2011. The creeks included in this study are Pages and Futch Creek, which drain into the Atlantic
Intracoastal Waterway (ICW) and Lords, Motts, Barnards, Smith, and Prince Georges Creek,
which drain into the Cape Fear River (Figure 1) (Table 1). Thirteen (13) of the nineteen (19)
sampling sites were previously monitored by the University of North Carolina at Wilmington. In
order to assess any changes to historical trends within individual sites and entire watersheds, data
provided by UNCW has been analyzed and incorporated into the results and discussion section
of this report. Photographs of each sampling site are found in Appendix A.
2
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Table 1. List of Sampling Sites
Creek Name Site Name Site Code Latitude Longitude
Motts Creek Carolina Beach Road MOT-CBR 34° 08.610 77° 53.830
Motts Creek Normandy Drive MOT-ND 34° 08.373 77° 54.580
Lords Creek River Road LC-RR 34° 05.185 77° 55.275
Barnards Creek Carolina Beach Road BC-CBR 34° 09.522 77° 54.712
Smith Creek Castle Hayne Road SC-CH 34° 15.541 77° 56.325
Smith Creek 23rd Street SC-23 34° 15.472 77° 55.178
Smith Creek Candlewood Drive SC-CD 34° 17.438 77° 51.332
Smith Creek North Kerr SC-NK 34° 15.744 77° 53.256
Smith Creek Gordon Road SC-GR 34° 16.639 77° 52.037
Prince Georges Creek Marathon Landing PG-ML 34° 21.088 77° 55.349
Prince Georges Creek Castle Hayne Road PG-CH 34° 20.675 77° 54.217
Prince Georges Creek North College PG-NC 34° 20.331 77° 53.607
Futch Creek 4 FC-4 34° 18.068 77° 44.760
Futch Creek 6 FC-6 34° 18.178 77° 45.038
Futch Creek 13 FC-13 34° 18.214 77° 45.451
Futch Creek Foy Branch FC-FOY 34° 18.405 77° 45.358
Pages Creek Mouth PC-M 34° 16.209 77° 46.270
Pages Creek Bayshore Drive Down Stream PC-BDDS 34° 16.685 77° 47.673
Pages Creek Bayshore Drive Up Stream PC-BDUS 34° 16.623 77° 48.104
3
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 1. Map of New Hanover County and watersheds included in this study
The State of North Carolina has employed a series of classifications that apply to all waters in
the State including streams, rivers, and lakes (NC Administrative Code, section 15A NCAC 2B
.0200). These classifications are meant to protect the specified uses within waterbodies. These
include aquatic life survival and reproduction, secondary recreation, primary recreation,
shellfishing, and water supply. The classifications that apply to the creeks examined in this
study are:
4
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
C Sw: Freshwater that is protected for aquatic life and secondary recreation uses. The
“Sw” supplemental classification indicates that these are swamp waters, and so are likely
to have lower dissolved oxygen and pH than non-swamp streams due to natural
conditions. However, a majority of the sites, including Lords Creek, Motts Creek,
Barnards Creek, Smith Creek, and Prince Georges Creek, designated as C Sw by the
State, are tidally influenced and have a brackish salinity range.
SA: Saline water bodies that are protected for shellfishing uses. This use requires a more
stringent standard for fecal coliform. Areas protected for shellfishing are also subject to
the protection requirements for the less stringent classifications of SC and SB, which
include aquatic life, secondary recreation, and primary recreation. This designation
applies to Futch Creek and Pages Creek.
1.1 Parameters
Physical, chemical, and biological water quality monitoring data are currently being collected for
this study. Physical parameters include temperature, salinity, conductivity, pH, turbidity, and
dissolved oxygen. Chemical parameters monitored in this study include orthophosphate and
nitrate/nitrite. Biological parameters include Chlorophyll-a and two suites of fecal indicator
bacteria: Enterococci and fecal coliform bacteria. Due to limited funding, fecal coliform
samples were only collected from sampling sites located within Futch Creek and Pages Creek.
Temperature:
Thermal pollution can result in significant changes to the aquatic environment. Most aquatic
organisms are adapted to survive within a specific temperature range. Thermal pollution may
also increase the extent to which fish are vulnerable to toxic compounds, parasites, and disease.
If temperatures reach extremes of heat or cold, few organisms will survive.
Thermal pollution may be caused by stormwater runoff from warm surfaces such as streets and
parking lots. Soil erosion is another cause, since it can cause cloudy conditions in a water body.
Cloudy water absorbs the sun's rays, resulting in a rise in water temperature. Thermal pollution
may even be caused by the removal of trees and vegetation which normally shade the water
body. In addition to the direct effects of thermal pollution on aquatic life, there are numerous
indirect effects. Thermal pollution results in lowered levels of dissolved oxygen, since cooler
water can hold more oxygen than warmer water.
Salinity:
Salinity is a measure of the amount of sodium chloride ions dissolved in water. This is important
to monitor since changes in the levels of salt concentration can impact the ability of salt sensitive
species to survive. An estuary, such as the lower Cape Fear River, usually exhibits a gradual
change in salinity throughout its length, as freshwater entering the estuary from tributaries mixes
with seawater moving in from the ocean. Salinity levels control, to a large degree, the types of
plants and animals that can live in different zones of the estuary. Freshwater species may be
restricted to the upper reaches of the estuary, while marine species inhabit the estuarine mouth.
Some species tolerate only intermediate levels of salinity while broadly adapted species can
acclimate to any salinity ranging from freshwater to seawater.
5
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Conductivity:
Specific conductance is a measure of the ability of water to conduct an electrical current.
Similar to salinity, it measures the amount of dissolved ions (including sodium chloride) in the
water.
pH:
The pH of water is a measurement of the concentration of H+ ions, using a scale that ranges from
0 to 14. Natural water usually has a pH between 6.5 and 8.5. While there are natural variations
in pH, many pH variations are due to human influences. Unanticipated decreases in pH could be
indications of acid rain, runoff from acidic soils, or contamination by agricultural chemicals.
Turbidity:
Turbidity is the amount of particulate matter that is suspended in water. Turbidity measures the
scattering effect that suspended solids have on light: the higher the intensity of scattered light,
the higher the turbidity. During a rainstorm, particles from the surrounding land are washed into
the river making the water a muddy brown color, indicating higher turbidity.
Dissolved Oxygen:
Dissolved oxygen (DO) refers to the volume of oxygen that is contained in water. Oxygen enters
the water as rooted aquatic plants and algae undergo photosynthesis and as oxygen is transferred
across the air-water interface. The amount of oxygen that can be held by the water depends on
the water temperature, salinity, and pressure.
Rapidly moving water, such as in a flowing stream, tends to contain a lot of dissolved oxygen,
while stagnant water contains little. Oxygen levels are also affected by the diurnal (daily) cycle.
Plants, such as rooted aquatic plants and algae produce excess oxygen during the daylight hours
when they are photosynthesizing. During the dark hours they must use oxygen for life processes.
Bacteria in water can consume oxygen as organic matter decays. Thus, excess organic material
in waterbodies can cause oxygen deficits. Aquatic life can become stressed or die in stagnant
water containing high levels of rotting, organic material in it, especially in summer, when
dissolved-oxygen levels are at a seasonal low.
Phosphates:
Phosphorus is a nutrient required by all organisms for the basic processes of life. Phosphorus is a
natural element found in rocks, soils and organic material. Phosphorus clings tightly to soil
particles and is used by plants, so its concentration in clean waters is generally very low.
However, phosphorus is used extensively in fertilizer and other chemicals, so it can be found in
higher concentrations in areas of human activity. High levels in the water column can be
detrimental to water quality as phosphates can cause algal blooms resulting in decreased
dissolved oxygen levels.
Orthophosphate is sometimes referred to as "reactive phosphorus." Orthophosphate is the most
stable kind of phosphate, and is the form used by plants. Orthophosphate is produced by natural
processes and is found in sewage.
6
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Nitrate/Nitrite:
Nitrate is highly soluble (dissolves easily) in water and is stable over a wide range of
environmental conditions. It is easily transported in streams and groundwater. Nitrates feed
plankton (microscopic plants and animals that live in water), aquatic plants, and algae, which are
then eaten by fish. Nitrite is relatively short-lived in water because it is quickly converted to
nitrate by bacteria.
Excessive concentrations of nitrate and/or nitrite can be harmful to humans and wildlife. If
excessive amounts of nitrates are added to the water, algae and aquatic plants can be produced in
large quantities. When these algae die, bacteria decompose them, and use up oxygen.
Chlorophyll-a:
Chlorophyll-a is a green pigment found in plants. It absorbs sunlight and converts it to sugar
during photosynthesis. Chlorophyll-a concentrations are an indicator of phytoplankton
abundance and biomass in coastal and estuarine waters. High levels often indicate an algal
bloom which can induce the depletion of oxygen in the water column due to the microbial
degradation of plant cells. Chlorophyll-a concentrations are often higher after rainfall,
particularly if the rain has flushed nutrients into the water. Higher chlorophyll-a levels are also
common during the summer months when water temperatures and light levels are high because
these conditions lead to greater phytoplankton numbers.
Fecal Coliform:
Fecal Coliform bacteria are present in the feces and intestinal tracts of humans and other warm-
blooded animals, and can enter water bodies from human and animal waste. If a large number of
fecal coliform bacteria are found in water, it is possible that pathogenic (disease- or illness-
causing) organisms are also present in the water. Pathogens are typically present in such small
amounts it is impractical to monitor them directly. High concentrations of the bacteria in water
may be caused by septic tank failure, poor animal keeping practices, pet waste, and urban runoff.
In order to adequately assess human health risks and develop watershed management plans, it is
necessary to know the sources of fecal contamination.
Enterococci:
Enterococci are distinguished from fecal coliform bacteria by their ability to survive in saltwater,
and in this respect they more closely mimic many pathogens than do the other indicators.
Enterococci are typically more human-specific than the larger fecal streptococcus group. EPA
recommends Enterococci as the best indicator of health risk in saltwater used for recreation and
as a useful indicator in freshwater as well. In 2004, Enterococci took the place of fecal coliform
as the new federal standard for water quality at public beaches. It is believed to provide a higher
correlation than fecal coliform with many of the human pathogens often found in sewage (Jeng,
et al., 2004). Results indicated that Enterococci might be a more stable indicator than fecal
coliform and, consequently, a more conservative indicator under brackish water conditions.
1.2 Standards
Water quality standards have been established legislatively for a number of these parameters
(Table 2). Many of the water quality standards are described in the NC Administrative Code,
section 15A NCAC 2H .0100. The water quality standards for Enterococci bacteria are
7
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
described by the US EPA (US EPA, 1986) and in the NC Administrative Code, section 15A
NCAC 18A .3402. The US EPA standards for Enterococci bacteria are based on incidents of
gastrointestinal illness following contact with bathing waters. Bacterial contamination is
quantified by “colony forming units” or CFU. Single sample maximum allowable Enterococci
density is 104 CFU/100ml, 158 CFU/100ml, 276 CFU/100ml, and 501 CFU/100ml for
designated beach areas, swimming areas with moderate to full body contact, lightly used full
body contact swimming areas, and infrequently used full body contact swimming areas,
respectively (Table 3). When at least five samples are collected within a 30 day period, the US
EPA recommends utilizing a geometric mean standard of 35 CFU/100ml. Geometric means are
often useful summaries for highly skewed data, as are often found with bacteriological datasets.
The North Carolina Recreational Water Quality Program (RWQ) adopted similar standards for
Enterococci bacteria, also determined by the frequency of swimming activity. As defined by
RWQ, Tier I swimming areas are used daily during the swimming season, Tier II swimming
areas are used three days a week during the swimming season, and Tier III swimming areas are
used on average 4 days a month during the swimming season. Single sample standards for Tiers
I, II, and III are 104 CFU/100ml, 276 CFU/100ml, and 500 CFU/100ml, respectively (Table 4).
A geometric mean of 35 CFU/100ml within Tier I swimming areas may also be utilized if at
least five samples are collected within 30 days. The creeks included in this study have not been
classified within the RWQ tier system; however an analysis of accessibility as an indicator of
swimming and boating usage has been performed (Table 5). Based on this analysis, of the
nineteen (19) sampling sites, three (3) could be considered Tier II and sixteen (16) could be
considered Tier III.
Table 2. North Carolina Water Quality Standards
Parameter Standard for SA Waters Standard for C Sw Waters
Dissolved Oxygen 5.0 mg/l 4.0 mg/la
Turbidity 25 NTU 50 NTU
pH 6.8-8.5 6.0-9.0b
Chlorophyll-a 40.0 ug/l 40.0 ug/l
Fecal Coliform Geometric Mean (5 samples within
30 days) <14 CFU/100ml; or 10%
of samples <43 CFU/100ml
Geometric Mean (5 samples within
30 days) <200 CFU/100ml; or single
sample <400 CFU/100ml
Enterococci c Geometric Mean (5 samples within
30 days) <35 CFU/100ml
Geometric Mean (5 samples within
30 days) <35 CFU/100ml
(a) Swamp waters may have lower values if caused by natural conditions (b) For swamp streams, pH may be as low as 4.3 if caused by natural conditions
(c) See Table 4 for single sample standards based off the tiered system employed by NC DENR Recreational Water
Quality Program
Table 3. Single sample standards for Enterococci as determined by the US EPA
Single sample maximum
Designated beach areas < 104 CFU/100ml
Swimming areas with moderate full body contact < 158 CFU/100ml
Lightly used full body contact swimming areas < 276 CFU/100ml
Infrequently used full body contact swimming areas < 501 CFU/100ml
8
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Table 4. Single sample standards for Enterococci as determined by the NC DENR
Recreational Water Quality Program
Single sample maximum
Tier I, swimming areas used daily during the
swimming season <104 CFU/100ml
Tier II, swimming areas used three days a week
during the swimming season <276 CFU/100ml
Tier III, swimming areas used on average four days
a month during the swimming season <500 CFU/100ml
Table 5. Proposed Tier Classification for New Hanover County Water Quality Monitoring
Sampling Sites
Site Name
Proposed
Tier
Classification
Accessible
for
Boating or
Swimming Comments
MOT-CBR Tier III No Adjacent to culvert off Carolina Beach Road
MOT-ND Tier III No Adjacent to small bridge on Normandy Drive
LC-RR Tier III No Adjacent to bridge on River Road
BC-CBR Tier III No Adjacent to culvert off Carolina Beach Road
SC-CH Tier III No Adjacent to bridge on Castle Hayne Road
SC-23 Tier III No Adjacent to bridge on 23rd Street
SC-CD Tier III No Narrow, shallow. Adjacent to Candlewood Drive
SC-NK Tier II Yes Small boat launch site off North Kerr
SC-GR Tier III No Adjacent to culvert on Gordon Road
PG-ML Tier III No Small boat launch site on private property
PG-CH Tier III No Adjacent to culvert on Castle Hayne Road
PG-NC Tier III No Adjacent to culvert on North College Road
FC-4 Tier III No Private docks are the only means of direct access
FC-6 Tier III No Private docks are the only means of direct access
FC-13 Tier III No Private docks are the only means of direct access
FC-FOY Tier III No No clear access points (no docks on Foy branch)
PC-M Tier II Yes Direct access via docks and boat ramp at Pages Creek Marina
PC-BDDS Tier III No Private docks are the only means of direct access
PC-BDUS Tier II Yes Public boat ramp off Bayshore Drive
2.0 METHODS
The seven creeks included in this study were selected by County staff and individual sampling
sites were selected by County staff in consultation with Coastal Planning & Engineering of North
Carolina, Inc. These seven creeks are primarily located in the unincorporated portion of New
Hanover County. Sampling sites were accessed from land, generally near a bridge or culvert
9
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
crossing, or by boat. Each site was sampled one time per month during a high ebb tide. Tides
were determined utilizing the National Oceanic and Atmospheric Administration’s (NOAA)
Tides and Currents website (http://tidesandcurrents.noaa.gov/).
Due to time constraints, monthly sampling events were conducted on three subsequent days each
month. Lords Creek, Motts Creek, and Barnards Creek were visited on the first sampling day
while Smith Creek and Prince Georges Creek were visited the second day. Futch Creek and
Pages Creek were visited on the third day. Rainfall totals for the 24 hours prior to each sampling
event were obtained from observations recorded at Wilmington International Airport as reported
by NOAA’s National Weather Service web site (http://www.srh.noaa.gov/data/RAH/RTPRAH).
2.1 Physical Parameters
All physical measurements (temperature, salinity, conductivity, turbidity, dissolved oxygen, and
pH) were taken in situ utilizing a 6820 YSI Multiparameter Water Quality Probe linked to a YSI
650 MDS display unit. The YSI Probe was calibrated each day prior to use. Physical
measurements were taken from the surface at all sites (depth = 0.1m) and near the creek bottom
at sites with depths greater than 0.5m. Following each sampling trip, the YSI Probe was post-
calibrated following each sampling date to ensure that the physical parameters measured were
within an acceptable range.
2.2 Chemical and Biological Parameters
Water samples were obtained for the laboratory analysis of chemical (nitrate/nitrite and
orthophosphate) and biological (Enterococci, fecal coliform, and Chlorophyll-a) parameters.
These grab samples were collected in sterile bottles during a high ebb tide from the surface at
each site (depth = 0.1m). Water samples were placed on ice immediately following collection
and were delivered in coolers to Environmental Chemists, Inc. of Wilmington, North Carolina
for analysis. All analyses performed by Environmental Chemists, Inc. were conducted utilizing
the following standard EPA approved methods:
Orthophosphate: SM 4500E
Nitrate/Nitrite: EPA 353.2
Chlorophyll-a: SM 10200H
Fecal Coliform: SM 9222D
Enterococci: EnterolertE
3.0 RESULTS
The results described in this report represent the physical, biological, and chemical data collected
from all sampling sites on a monthly basis between June 2010 and May 2011. These results are
organized by watershed. All raw data, including parameters not summarized in this section, are
included in Appendix B.
3.1 Rating System
In order to provide a quick-glance assessment of the water quality within a particular sampling
station or watershed, a rating system for a number of parameters has been employed. This
quantitative system assigns a rating of “GOOD”, “FAIR”, or “POOR” to a sampling station
depending on the percentage of samples exceeding the State standard for dissolved oxygen,
10
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
turbidity, Chlorophyll-a, Enterococci, and fecal coliform bacteria. If the recorded value of a
parameter exceeds the State standard less than 10% of the times sampled, the station will receive
a “Good” rating for the parameter. A “Fair” rating is assigned when a parameter exceeds the
State standard 11-25% of the times sampled. Parameters measured that exceed the State
standard more than 25% of the sampling times are given a “Poor” rating.
3.2 Barnards Creek
The Barnards Creek watershed includes 4,953 acres and is located in the southwestern portion of
the County, just along the City line. The watershed drains portions of Carolina Beach Road at its
headwaters and flows towards River Road before entering into the Cape Fear River. Zoning
within the watershed is comprised of a mix of residential and commercial uses. The land is
classified as a mix of transition, urban, and conservation according to the CAMA land use plan.
This watershed contains approximately 16.9% impervious surface coverage (Hume, 2009).
Sampling was conducted at one site (BC-CBR) within the Barnards Creek watershed (Figure 2).
Surface dissolved oxygen within BC-CBR ranged between 4.5 mg/l and 9.4 mg/l with a mean
value of 7.1 mg/l (Table 6). These values were within an acceptable level above the State
standard of 4.0 mg/l for C Sw waters during all sampling events at both the surface and near the
bottom of the water column (Figure 3).
Chlorophyll-a ranged between 0.0 ug/l and 8.0 ug/l with a mean value of 2.0 ug/l at BC-CBR
(Table 6) . These values did not approach the 40ug/l standard.
Enterococci ranged between 55 CFU/100ml and 1,650 CFU/100ml with a geometric mean value
of 360 CFU/100ml, which is above the NCDENR standard of 500 CFU/100ml for Tier III waters
(Figure 4, Table 6). Five (5) of the twelve (12) samples collected during this period exceeded this
standard.
Nitrate/nitrite levels ranged between 0.03 mg/l and 0.15 mg/l with a mean of 0.11 mg/l (Table 6).
Orthophosphate levels ranged between 0.01 mg/l and 0.03 mg/l with a mean of 0.01 mg/l (Table
6).
Turbidity values were generally good ranging between 0 and 12 NTU with a mean value of 4
NTU (Table 6). No observations exceeded the State standard of 50 NTU for C SW waters.
Table 7 depicts the ratings for these parameters for the watershed.
11
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 2. Water Quality Sites within the Barnards Creek Watershed
Table 6. Mean values of select parameters from Barnards Creek. Range in parentheses.
Parameter BC-CBR
Turbidity (NTU) 4 (0-12)
Dissolved Oxygen (mg/l) 7.1 (4.5-9.4)
Nitrate/Nitrite (mg/l) 0.11 (0.03-0.15)
Orthophosphate (mg/l) 0.01 (0.01-0.03)
Chlorophyll-a (ug/l) 2.0 (0.0-8.0)
Enterococci (#CFU/100ml) 360 (55-1650)1
(1)Enterococci values expressed as geometric mean
12
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 3. Dissolved Oxygen at BC-CBR
Figure 4. Enterococci at BC-CBR
Table 7. Ratings of parameters within sampling stations within Barnards Creek
Parameter BC-CBR
Turbidity GOOD
Dissolved Oxygen GOOD
Chlorophyll-a GOOD
Enterococci POOR
13
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
3.3 Futch Creek
Futch Creek is located on the New Hanover-Pender County line and drains into the Intracoastal
Waterway. The Futch Creek watershed encompasses approximately 3,136 acres extending from
Scotts Hill Loop Road and Highway 17 on the north and east, to Porters Neck Road on the south.
Zoning within the Futch Creek watershed is predominately residential with a small business
district along Highway 17. The land within the Futch Creek watershed is classified as watershed
resource protection or transition in the CAMA land use plan. This watershed contains
approximately 11.0% impervious surface coverage (Hume, 2009). Sampling was conducted at
four (4) sites (FC-4, FC-6, FC-13, and FC-FOY) within the Futch Creek watershed (Figure 5).
Surface dissolved oxygen within the creek ranged between 2.9 mg/l and 10.5 mg/l with a mean
value of 6.3 mg/l (Figures 6-9, Table 8).
Chlorophyll-a ranged between 0.0 ug/l and 7.0 ug/l with a mean value of 2.5 ug/l (Table 8).
None of these values approached the 40ug/l Chlorophyll-a standard.
Enterococci ranged between 5 CFU/100ml and 210 CFU/100ml with a geometric mean value of
12 CFU/100ml. No samples collected within Futch Creek exceeded the NCDENR Enterococci
standard of 500 CFU/100ml for Tier III waters (Figures 10-13, Table 8).
The geometric mean of fecal coliform in Futch Creek was 15 CFU with a range of 5 to 273
CFUs. This geometric mean was above the NCDENR Shellfish Sanitation single-sample
standard of 14 CFU/100ml (Table 8). Twenty-three percent (23%) of all samples analyzed for
fecal coliform levels exceeded 43 CFU/100ml. The State standard requires “no more than 10%
of samples shall exceed 43 CFU/100ml)”.
Nitrate/nitrite levels ranged between 0.01 mg/l and 0.03 mg/l with a mean of 0.01 mg/l (Table 8)
Orthophosphate levels ranged between 0.01 mg/l and 0.04 mg/l with a mean of 0.01 mg/l (Table
8).
Turbidity values were generally low ranging between 0 and 12 NTU with a mean value of 2
NTU (Table 8). No observations exceeded the State standard of 25 NTU for SA waters.
Table 9 depicts the ratings for these parameters for the watershed.
14
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 5. Water Quality Sites within the Futch Creek Watershed
Table 8. Mean values of select parameters from Futch Creek. Range in parentheses.
Parameter FC-4 FC-6 FC-13 FC-FOY
Turbidity
(NTU) 1 (0-4) 1 (0-3) 3 (0-12) 3 (0-12)
Dissolved
Oxygen (mg/l) 6.6 (3.4-10.6) 6.3 (3.6-9.4) 6.1 (2.9-10.5) 6.0 (3.0-9.7)
Nitrate/Nitrite
(mg/l) 0.01 (0.01-0.01) 0.01 (0.01-0.01) 0.01 (0.01-0.03) 0.01 (0.01-0.03)
Orthophosphate
(mg/l) 0.01 (0.01-0.01) 0.01 (0.01-0.03) 0.02 (0.01-0.04) 0.01 (0.01-0.03)
Chlorophyll-a
(ug/l) 2.4 (1.0-5.0) 2.2 (0.0-5.0) 3.0 (1.0-7.0) 2.4 (0.0-6.0)
Enterococci
(#CFU/100ml) 9 (5-37)1 10 (5-55)1 19 (5-145)1 13 (5-210)1
Fecal Coliform
(#CFU/100ml) 11 (5-127)1 8 (5-118)1 23 (5-273)1 22 (5-200)1
(1)Enterococci and Fecal Coliform values expressed as geometric mean
15
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 6. Dissolved Oxygen at FC-4
Figure 7. Dissolved Oxygen at FC-6
Figure 8. Dissolved Oxygen at FC-13
16
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 9. Dissolved Oxygen at FC-FOY
Figure 10. Enterococci and Fecal Coliform at FC-4
Figure 11. Enterococci and Fecal Coliform at FC-6
17
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 12. Enterococci and Fecal Coliform at FC-13
Figure 13. Enterococci and Fecal Coliform at FC-FOY
Table 9. Ratings of parameters within sampling stations within Futch Creek
Parameter FC-4 FC-6 FC-13 FC-FOY
Turbidity GOOD GOOD GOOD GOOD
Dissolved Oxygen FAIR FAIR POOR POOR
Chlorophyll-a GOOD GOOD GOOD GOOD
Enterococci GOOD GOOD GOOD GOOD
Fecal Coliform FAIR FAIR POOR POOR
3.4 Lords Creek
The Lords Creek Watershed is located in the southwestern portion of the County and
encompasses approximately 3,047 acres. Zoning within the watershed is completely residential.
This watershed contains approximately 12.6% impervious surface coverage (Hume, 2009).
According to the CAMA land use plan, the land in the watershed is classified as a mix of
conservation, transition, watershed resource protection and a small natural heritage resource
protection designation. Sampling was conducted at one (1) site (LC-RR) within the Lords Creek
watershed (Figure 14).
18
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Surface dissolved oxygen LC-RR ranged between 4.4 mg/l and 11.4 mg/l with a mean value of
7.2 mg/l (Table 10). All values were within an acceptable level above the State standard of 4.0
mg/l for C Sw waters during both the surface and near the bottom of the water column (Figure
15).
Chlorophyll-a ranged between 1.0 ug/l and 27.0 ug/l with a mean value of 10.4 ug/l (Table 10).
Samples obtained in August 2009 exceeded the State standard of 40ug/l for Chlorophyll-a.
Enterococci ranged between 5 CFU/100ml and 290 CFU/100ml with a geometric mean value of
41 CFU/100ml (Table 10). No individual samples contained high levels of Enterococci beyond
the NCDENR standard of 500 CFU/100ml for Tier III waters.
Nitrate/nitrite levels ranged between 0.01 mg/l and 0.29 mg/l with a mean of 0.19 mg/l (Table
10).
Orthophosphate levels ranged between 0.01 mg/l and 0.17 mg/l with a mean of 0.06 mg/l (Table
10).
Turbidity values were generally moderate ranging between 1 and 30 NTU with a mean value of 8
NTU (Table 10). No observations exceeded the State standard of 50 NTU for C Sw waters in
Lords Creek during the study period.
Table 11 depicts the ratings for these parameters for the watershed.
19
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 14. Water Quality Site within the Lords Creek Watershed
Table 10. Mean values of select parameters from Lords Creek. Range in parentheses.
Parameter LC-RR
Turbidity (NTU) 8 (1-30)
Dissolved Oxygen (mg/l) 7.2 (4.4-11.4)
Nitrate/Nitrite (mg/l) 0.19 (0.01-0.29)
Orthophosphate (mg/l) 0.02 (0.01-0.04)
Chlorophyll-a (ug/l) 10.4 (1.0-27.0)
Enterococci (#CFU/100ml) 41 (5-290)1
(1)Enterococci values expressed as geometric mean
20
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 15. Dissolved Oxygen at LC-RR
Figure 16. Enterococci Levels at LC-RR
Table 11. Ratings of parameters within sampling stations within Lords Creek
Parameter LC-RR
Turbidity GOOD
Dissolved Oxygen GOOD
Chlorophyll-a GOOD
Enterococci GOOD
3.5 Motts Creek
Motts Creek watershed encompasses approximately 2,389 acres and is located in the
southwestern portion of the County, just below Sanders Road. The Creek drains portions of
Carolina Beach Road at its headwaters and then drains toward River Road before entering into
the Cape Fear River. Zoning in the watershed is predominately residential with commercial
business districts along Carolina Beach Road. Land in the watershed is classified as transition,
conservation or wetland resource protection according to the CAMA land use plan. This
watershed contains approximately 12.6% impervious surface coverage (Hume, 2009). Sampling
21
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
was conducted at two (2) sites (MOT-CBR, MOT-ND) within the Motts Creek watershed
between the months of June 2009 and May 2010 (Figure 17).
Surface dissolved oxygen within Motts Creek ranged between 3.2 mg/l and 9.7 mg/l with a mean
value of 6.5 mg/l (Figures 18 and 19, Table 12).
Chlorophyll-a ranged between 1.0 ug/l and 32.0 ug/l with a mean value of 4.0 ug/l (Table 12).
These values did not approach the 40ug/l standard.
Enterococci ranged between 127 CFU/100ml and 8,000 CFU/100ml with a geometric mean
value of 628 CFU/100ml (Table 12). MOT-ND and MOT-CBR each exceeded the NCDENR
standard of 500 CFU/100ml for Tier III waters during five (5) and seven (7) of the twelve (12)
times they were samples, respectively (Figures 20 and 21).
Nitrate/nitrite levels ranged between 0.02 mg/l and 0.19 mg/l with a mean of 0.08 mg/l (Table
12).
Orthophosphate levels ranged between 0.01 mg/l and 0.08 mg/l with a mean of 0.03 mg/l (Table
12).
Turbidity values were generally good ranging between 0 and 14 NTU with a mean value of 5
NTU (Table 12). No turbidity observations exceeded the State standard of 50 NTU for C Sw
waters.
Table 13 depicts the ratings for these parameters for the watershed.
22
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 17. Water Quality Sites within the Motts Creek Watershed
Table 12. Mean values of select parameters from Motts Creek. Range in parentheses.
Parameter MOT-CBR MOT-ND
Turbidity (NTU) 7 (0-14) 4 (0-10)
Dissolved Oxygen (mg/l) 7.4 (4.3-9.7) 5.5 (3.2-8.7)
Nitrate/Nitrite (mg/l) 0.8 (0.02-0.15) 0.09 (0.03-0.19)
Orthophosphate (mg/l) 0.02 (0.01-0.04) 0.03 (0.01-0.08)
Chlorophyll-a (ug/l) 3.0 (1.0-9.0) 5.0 (1.0-32.0)
Enterococci (#CFU/100ml) 576 (127-7000)1 684 (127-8000)1
(1)Enterococci values expressed as geometric mean
23
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 18. Dissolved Oxygen at MOT-CBR
Figure 19. Dissolved Oxygen at MOT-ND
Figure 20. Enterococci at MOT-CBR
24
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 21. Enterococci at MOT-ND
Table 13. Ratings of parameters within sampling stations within Motts Creek
Parameter MOT-CBR MOT-ND
Turbidity GOOD GOOD
Dissolved Oxygen GOOD GOOD
Chlorophyll-a GOOD GOOD
Enterococci POOR POOR
3.6 Pages Creek
Located in northeastern New Hanover County and encompassing 2,044 acres, Pages Creek
watershed drains into the Intracoastal Waterway, north of Middle Sound Loop Road. Zoning
within the Pages Creek watershed is predominately residential, with commercial zoning along
Highway 17. The land within the Pages Creek watershed is predominately classified as
watershed resource protection and conservation, with a small portion classified as transitional
according to the CAMA land use plan. This watershed contains approximately 23.2%
impervious surface coverage (Hume, 2009). Sampling was conducted at three (3) sites (PC-
BDDS, PC-BDUS, and PC-M) within the Motts Creek watershed (Figure 22).
Surface dissolved oxygen within Pages Creek ranged between 2.4 mg/l and 9.0 mg/l with a mean
value of 5.8 mg/ (Table 14). While dissolved oxygen at PC-M was acceptable during all
sampling events, the dissolved oxygen within PC-BDDS and PC-BDUS were lower than the
State standard of 5.0 mg/l for SA waters on numerous occasions (Figures 23 through 25).
Chlorophyll-a ranged between 0.0 ug/l and 27.0 ug/l with a mean value of 4.6 ug/l (Table 14).
No samples exceeded the State standard of 40 ug/l for chlorophyll-a.
Enterococci ranged between 5 CFU/100ml and 60,000 CFU/100ml with a geometric mean value
of 84 CFU/100ml (Figures 26-28, Table 14). While samples collected from PC-M did not
contain high levels of Enterococci, three (3) and four (4) samples from PC-BDDS and PC-
BDUS, respectively, contained levels higher than the NCDENR standards.
25
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Fecal coliform levels ranged between 5 CFU/100ml and 24,000 CFU/100ml with a geometric
mean of 86 CFU/100ml (Table 14). Fecal coliform levels exceeded the NCDENR Shellfish
Sanitation single-sample standard of 14 CFU/100ml on all twelve (12) sampling events at PC-
BDDS and eleven (11) occasions at PC-BDUS. This standard was breached at PC-M on three
(3) occasions (Figures 26 through 28). Seventy-two percent (72%) of all samples analyzed for
fecal coliform levels exceeded 43 CFU/100ml. The State standard allows “no more than 10% of
samples shall exceed 43 CFU/100ml”.
Nitrate/nitrite levels ranged between 0.01 mg/l and 0.06 mg/l with a mean of 0.01 mg/l (Table
14).
Orthophosphate levels ranged between 0.01 mg/l and 0.1 mg/l with a mean of 0.03 mg/l (Table
14).
Turbidity values were generally good ranging between 0 and 20 NTU with a mean value of 5
NTU (Table 14). None of the observed turbidity values exceeded the State standard of 25 NTU
for class SA waters.
Table 15 depicts the ratings for these parameters for the watershed.
26
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 22. Water Quality Sites within the Pages Creek Watershed
Table 14. Mean values of select parameters from Pages Creek. Range in parentheses.
Parameter PC-BDUS PC-BDDS PC-M
Turbidity (NTU) 6 (0-20) 6 (0-20) 2 (0-9)
Dissolved Oxygen (mg/l) 5.7 (2.8-9.0) 5.5 (2.4-8.8) 6.3 (2.9-9.0)
Nitrate/Nitrite (mg/l) 0.01 (0.01-0.03) 0.01 (0.01-0.02) 0.02 (0.01-0.06)
Orthophosphate (mg/l) 0.04 (0.02-0.1) 0.02 (0.01-0.06) 0.01 (0.01-0.01)
Chlorophyll-a (ug/l) 6.8 (0.0-27.0) 4.5 (0.0-19.0) 2.5 (0.5-6.0)
Enterococci (#CFU/100ml) 672 (5-33000)1 265 (10-60000)1 10 (5-172)1
Fecal Coliform
(#CFU/100ml) 457 (82-24000)1 122 (5-1273)1 11 (5-163)1
(1)Enterococci and fecal coliform values expressed as geometric mean
27
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 23. Dissolved Oxygen at PC-BDDS
Figure 24. Dissolved Oxygen at PC-BDUS
Figure 25. Dissolved Oxygen at PC-M
28
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 26. Enterococci and Fecal Coliform at PC-BDDS
Figure 27. Enterococci and Fecal Coliform at PC-BDUS
Figure 28. Enterococci and Fecal Coliform at PC-M
29
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Table 15. Ratings of parameters within sampling stations within Pages Creek
Parameter PC-BDDS PC-BDDS PC-M
Turbidity GOOD GOOD GOOD
Dissolved Oxygen POOR POOR FAIR
Chlorophyll-a GOOD GOOD GOOD
Enterococci FAIR POOR GOOD
Fecal Coliform POOR POOR FAIR
3.7 Prince Georges
Prince Georges Creek drains into the Cape Fear River. The Prince Georges Creek watershed is
approximately 14,589 acres and drains most of Castle Hayne, extending eastward across I-40
into the Blue Clay Road area. Zoning within the Prince Georges Creek watershed is
predominately residential with some business and light industrial districts within Castle Hayne.
Most of the land within the Prince Georges Creek watershed is classified as aquifer resource
protection, conservation or transition according to the CAMA land use plan. This watershed
contains approximately 10.1% impervious surface coverage (Hume, 2009). Sampling was
conducted at three (3) sites (PG-CH, PG-ML, and PG-NC) within the Prince Georges Creek
watershed (Figure 29).
Surface dissolved oxygen within Prince Georges Creek ranged between 1.8 mg/l and 9.7 mg/l
with a mean value of 5.4 mg/l (Table 16). Surface dissolved oxygen values at PG-CH and PG-
NC were below the State standard of 4.0 mg/l for C Sw during seven (7) and six (6) sampling
events, respectively. PG-ML was below the standard on three (3) occasions (Figures 30 through
32).
Chlorophyll-a ranged between 0.0 ug/l and 25.0 ug/l with a mean value of 5.1 ug/l (Table 16).
These values did not exceed the 40ug/l standard.
Enterococci ranged between 5 CFU/100ml and 3,200 CFU/100ml with a geometric mean value
of 213 CFU/100ml (Table 16). During this study, five (5) and eight (8) samples from PG-CH
and PG-ML, respectively, contained Enterococci levels above the NCDENR standard of 500
CFU/100ml for Tier III waters. No samples from PG-NC exceeded this value during the same
time period (Figures 33 through 35).
Nitrate/nitrite levels ranged between 0.01 mg/l and 0.18 mg/l with a mean of 0.7 mg/l (Table 16).
Orthophosphate levels ranged between 0.01 mg/l and 0.1 mg/l with a mean of 0.03 mg/l (Table
16).
Turbidity values were generally good ranging between 0 and 32 NTU with a mean value of 3
NTU (Table 16). No observed turbidity values exceeded the State standard of 50 NTU for C Sw
waters.
Table 17 depicts the ratings for these parameters for the watershed.
30
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 29. Water Quality Sites within the Prince Georges Creek Watershed
Table 16. Mean values of select parameters from Prince Georges Creek. Range in
parentheses.
Parameter PG-CH PG-ML PG-NC
Turbidity (NTU) 3 (0-16) 0 (0-3) 7 (0-32)
Dissolved Oxygen (mg/l) 5.1 (1.8-8.7) 6.0 (3.1-9.7) 4.0 (0.1-9.3)
Nitrate/Nitrite (mg/l) 0.11 (0.01-0.18) 0.05 (0.01-0.14) 0.05 (0.01-0.14)
Orthophosphate (mg/l) 0.02 (0.01-0.05) 0.04 (0.01-0.08) 0.02 (0.01-0.10)
Chlorophyll-a (ug/l) 4.3 (0.0-2.5) 5.3 (0.0-15.0) 5.8 (0.0-18.0)
Enterococci (#CFU/100ml) 291 (37-3200)1 512 (208-1,455)1 65 (5-490)1
(1)Enterococci values expressed as geometric mean
31
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 30. Dissolved Oxygen at PG-CH
Figure 31. Dissolved Oxygen at PG-ML
Figure 32. Dissolved Oxygen at PG-NC
32
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 33. Enterococci at PG-CH
Figure 34. Enterococci and Fecal Coliform at PG-ML
Figure 35. Enterococci at PG-NC
33
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Table 17. Ratings of parameters within sampling stations within Prince Georges Creek
Parameter PG-CH PG-ML PG-NC
Turbidity GOOD GOOD GOOD
Dissolved Oxygen POOR FAIR POOR
Chlorophyll-a GOOD GOOD GOOD
Enterococci POOR POOR GOOD
3.8 Smith Creek
Located in north-central New Hanover County and containing approximately 14,665 acres, the
Smith Creek watershed drains into the lower northeast Cape Fear River, just north of the Isabelle
Holmes Bridge. The watershed drains land within the City limits and the unincorporated
County, including the Wilmington International Airport. Zoning within the Smith Creek
watershed is a mix of industrial, residential, and commercial. The land within the watershed is
predominately classified as urban and transition, with a small portion classified as conservation.
This watershed contains approximately 21.9% impervious surface coverage (Hume, 2009).
Along with increased development and impervious surfaces, water quality in Smith Creek has
declined in recent years. High bacteria levels have been reported, as well as low dissolved
oxygen levels. As a result, Smith Creek has been listed on the 303(d) list for impaired waters
due to impaired biological integrity. Sampling was conducted at five (5) sites (SC-CH, SC-23,
SC-NK, SC-GR, SC-CD) within the Smith Creek watershed (Figure 36).
Surface dissolved oxygen within the creek ranged between 3.0 mg/l and 11.5 mg/l with a mean
value of 6.9 mg/l (Table 18). With the exception of observations from SC-23, SC-CD, and SC-
NK in August 2010, these values were within an acceptable level above the State standard of 4.0
mg/l for C Sw waters (Figures 37 through 41).
Chlorophyll-a ranged between 0.0 ug/l and 67.0 ug/l with a mean value of 7.3 ug/l (Table 18).
Two samples exceeded the State Standard for chlorophyll-a.
Enterococci ranged between 28 CFU/100ml and 12,000 CFU/100ml with a geometric mean
value of 329 CFU/100ml (Table 18). A number of samples exceeded the NCDENR standard of
500 CFU/100ml for Tier III waters including ten (10) from SC-CD and nine (9) from SC-GR.
Fiver (5) samples from SC-NK exceeded the NCDENR standard of 276 CFU/100ml for Tier II
waters (Figures 42 through 46).
Nitrate/nitrite levels ranged between 0.01 mg/l and 0.47 mg/l with a mean of 0.15 mg/l (Table
18).
Orthophosphate levels ranged between 0.01 mg/l and 0.11 mg/l with a mean of 0.05 mg/l (Table
18).
Turbidity values were generally good ranging between 0 and 72 NTU with a mean value of 5
NTU (Table 18). One observation from SC-CH exceeded the State standard of 50 NTU for SW
class C waters.
Table 19 depicts the ratings for these parameters for the watershed.
34
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 36. Water Quality Sites within the Smith Creek Watershed
Table 18. Mean values of select parameters from Smith Creek. Range in parentheses.
Parameter SC-23 SC-CD SC-CH SC-GR SC-NK
Turbidity
(NTU) 9 (1-28) 1 (0-8) 14 (0-72) 1 (0-6) 2 (0-6)
Dissolved
Oxygen (mg/l) 6.6 (3.3-11.4) 7.8 (3.0-10.8) 6.8 (4.0-11.5) 7.8 (4.3-10.9) 6.5 (3.1-11.0)
Nitrate/Nitrite
(mg/l) 0.17 (0.02-0.25) 0.09 (0.01-0.17) 0.31 (0.02-0.47) 0.10 (0.02-0.15) 0.07 (0.01-0.15)
Orthophosphate
(mg/l) 0.07 (0.04-0.11) 0.02 (0.01-0.04) 0.08 (0.04-0.11) 0.03 (0.01-0.11) 0.03 (0.01-0.07)
Chlorophyll-a
(ug/l) 10.0 (1.0-24.0) 8.1 (0.5-67.0) 3.8 (1.0-8.0) 2.3 (0.0-7.0) 12.4 (1.0-46.0)
Enterococci
(#CFU/100ml) 93 (28-270)1 1993 (154-12000)1 83 (28-181)1 1077 (380-
10,000)1 231 (28-819)1
(1)Enterococci values expressed as geometric mean
35
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 37. Dissolved Oxygen at SC-23
Figure 38. Dissolved Oxygen at SC-CD
Figure 39. Dissolved Oxygen at SC-CH
36
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 40. Dissolved Oxygen at SC-GR
Figure 41. Dissolved Oxygen at SC-NK
Figure 42. Enterococci at SC-23
37
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 43. Enterococci at SC-CD
Figure 44. Enterococci at SC-CH
Figure 45. Enterococci at SC-GR
38
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 46. Enterococci at SC-NK
Table 19. Ratings of parameters within sampling stations within Smith Creek
Parameter SC-23 SC-CD SC-CH SC-GR SC-NK
Turbidity FAIR GOOD GOOD GOOD GOOD
Dissolved Oxygen GOOD GOOD GOOD GOOD GOOD
Chlorophyll-a GOOD GOOD GOOD GOOD GOOD
Enterococci GOOD POOR GOOD POOR POOR
3.9 Comprehensive Rating by Watershed
When combining all results from each site within individual watersheds, it is possible to obtain a
“snapshot” of water quality within each watershed (Table 20). Barnards Creek demonstrates
“good” water quality with the exception of Enterococci, which was in the “poor” category.
Futch Creek also contains good ratings; however dissolved oxygen was shown to be “fair” while
fecal coliform was determined to be “poor”. Lords Creek was deemed “good” for all parameters.
Smith Creek and Motts Creek rated “good” for all parameters with the exception of “poor” for
Enterococci. Pages Creek also demonstrated “good” ratings for turbidity and chlorophyll-a,
however dissolved oxygen and fecal coliform were “poor” while Enterococci was “fair”. Prince
Georges Creek had “good” ratings for turbidity and chlorophyll-a and “poor” ratings for
dissolved oxygen and Enterococci.
Table 20. Ratings of parameters within each watershed
Parameter Barnards
Creek
Futch
Creek
Lords
Creek
Motts
Creek
Pages
Creek
Prince
Georges
Creek
Smith
Creek
Turbidity GOOD GOOD GOOD GOOD GOOD GOOD GOOD
Dissolved Oxygen GOOD FAIR GOOD GOOD POOR POOR GOOD
Chlorophyll-a GOOD GOOD GOOD GOOD GOOD GOOD GOOD
Enterococci POOR GOOD GOOD POOR FAIR POOR POOR
Fecal Coliform N/A POOR N/A N/A POOR N/A N/A
39
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
3.10 Long Term Trends
Water quality data has been collected within New Hanover County since the mid 1990’s.
Several of the historical monitoring sites continue to be utilized for the ongoing monitoring
effort. In order to assess the long term trends in water quality, a database has been created to
include the all data collected within the seven (7) tidal creeks under current investigation. Prior
to 2007, UNCW collected data within three (3) of the tidal creeks included in the present study.
These include Pages Creek, Futch Creek, and Smith Creek. Accordingly, the data from these
three creeks dating to 2004 has been incorporated in the analysis of long term trends. The long
term trends from the remaining creeks (Motts Creek, Lords Creek, Prince Georges Creek, and
Barnards Creek) have been derived from data obtained between November 2007 to the present.
For each parameter examined, data was plotted on a line graph over time and a trend line was
created. Trend lines, also known as regression lines, can be used as a way of visually depicting
the relationship between the independent (x) and dependent (y) variables in the graph. In this
case the independent variable is time and the dependent variable is the water quality parameter.
A trend in water quality is defined as an increase or decrease in a particular constituent
concentration over time. Statistical analysis was not performed; therefore the significance of
these long term trends should be interpreted with caution.
3.10.1 Dissolved Oxygen
Figures 47-53 depicts the long term trends in dissolved oxygen within the seven (7) creeks
examined within this study. The figures illustrate a distinct seasonal pattern including higher
dissolved oxygen during the cooler winter months and lower dissolved oxygen during the
warmer summer months. Generally speaking, the dissolved oxygen levels within each creek
have not changed drastically from year to year. The apparent increasing trend line associated
with Smith Creek is not necessarily representative of an actual improvement in dissolved oxygen
levels due to the fact that sampling was only conducted seasonally between 2004 and 2006
thereby skewing the data. Since 2007, dissolved oxygen levels exceeded the State standard
within surface samples 30%, 23%, and 20% of the time within Prince Georges Creek, Pages
Creek, and Futch Creek, respectively. Dissolved oxygen levels were better within Smith Creek,
Motts Creek, and Lords Creek where the State standard was breached 8%, 5%, and 2%,
respectively. None of the observations within Barnards Creek exceeded the dissolved oxygen
standard.
40
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 47- Long term surface dissolved oxygen data within Barnards Creek
Figure 48- Long term surface dissolved oxygen data within Futch Creek
Figure 49- Long term surface dissolved oxygen data within Lords Creek
41
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 50- Long term surface dissolved oxygen data within Motts Creek
Figure 51- Long term surface dissolved oxygen data within Pages
Figure 52- Long term surface dissolved oxygen data within Prince Georges Creek
42
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 53- Long term surface dissolved oxygen data within Smith Creek
3.10.2 Turbidity
Figures 54-60 depict the long term trends in turbidity within the seven (7) creeks examined
within this study. In general, the long term trend of turbidity has remained fairly constant within
each creek on an annual basis, however seasonal patterns emerge. This includes higher turbidity
observations during the warmer months and lower turbidity during the cooler months. The
trends within Futch Creek and Lords Creek have demonstrated a slight decrease in turbidity over
time. Turbidity has remained within the State standard within all sampling sites included within
this long term analysis.
Figure 54- Long term surface turbidity data within Barnards Creek
43
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 55- Long term surface turbidity data within Futch Creek
Figure 56- Long term surface turbidity data within Lords Creek
Figure 57- Long term surface turbidity data within Motts Creek
44
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 58- Long term surface turbidity data within Pages Creek
Figure 59- Long term surface turbidity data within Prince Georges Creek
Figure 60- Long term surface turbidity data within Smith Creek
45
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
3.10.3 Chlorophyll-a
Figures 61-67 depict the long term trends in chlorophyll-a within the seven (7) creeks examined
within this study. In general, the long term trend of turbidity has remained fairly constant within
each creek. Similar to the trend observed with dissolved oxygen, chlorophyll-a levels appear to
increase during the warmer months and decrease during the cooler months. Since sampling
began, only several exceedences of the chlorophyll-a standard were observed.
Figure 61- Long term chlorophyll-a data within Barnards Creek
Figure 62- Long term chlorophyll-a data within Futch Creek
46
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 63- Long term chlorophyll-a data within Lords Creek
Figure 64- Long term chlorophyll-a data within Motts Creek
Figure 65- Long term chlorophyll-a data within Pages Creek
47
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 66- Long term chlorophyll-a data within Prince Georges Creek
Figure 67- Long term chlorophyll-a data within Smith Creek
3.10.4 Enterococci
Figures 68-74 depict the long term trends in Enterococci within the seven (7) creeks examined
within this study. Motts Creek, Barnards Creek, Smith Creek, and Prince Georges Creek have
all maintained a relatively high level of bacteria over time. Pages Creek also contains high levels
of bacteria which has apparently increased within recent years; however this increase may be due
to several anomalously high individual samples. The opposite trend was observed within Lords
Creek where relatively low Enterococci levels appear to decrease over time. Futch Creek,
however, has maintained consistent low levels of Enterococci since sampling began in 2007.
Since November 2007, samples collected within Motts Creek, Barnards Creek, and Smith Creek
exceeded the State standard for Enterococci 36%, 35%, and 34% of the time, respectively. Both
Prince Georges Creek and Pages Creek exceeded this standard 24% of the time while Lords
Creek and Futch Creek exceeded the standard 6% and 2%, respectively.
48
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 68- Long term Enterococci data within Barnards Creek
Figure 69- Long term Enterococci data within Futch Creek
Figure 70- Long term Enterococci data within Lords Creek
49
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 71- Long term Enterococci data within Motts Creek
Figure 72- Long term Enterococci data within Pages Creek
Figure 73- Long term Enterococci data within Prince Georges Creek
50
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 74- Long term Enterococci data within Smith Creek
DISCUSSION
Water quality is an important issue in the region due to the fact that there are many economic and
recreational opportunities that are supported by the aquatic resources in and around these
waterways. One of the greatest threats to water quality in this area is stormwater runoff created
by increased impervious surface coverage (Mallin et al., 2000). Polluted stormwater runoff can
have many adverse effects on plants, fish, animals and people. Excess nutrients can cause algal
blooms while bacteria and other pathogens can wash into swimming areas and create health
hazards. New Hanover County has experienced rapid growth and development over the past
several decades. In 1990, the population within the County was 120,284. By 2006, the
population grew over 50% to 182,591 (U.S. Census Bureau, 2006). The most recent assessment
conducted in 2010 determined the population to be 202,667. Along with this population increase
and subsequent stormwater runoff, numerous septic tanks, aging wastewater infrastructure, and
other factors potentially impact the water quality within the County’s creeks. With this in mind,
it is important to monitor the water quality of these local systems to determine potential impacts
to both human health and ecosystem function.
Typically, water quality degrades as the water temperature increases and oxygen is not as readily
dissolved in the water column. This was observed while investigating the long term trends of
water quality in this study. The dissolved oxygen along with chlorophyll-a and turbidity levels
increased during the warmer summer months. Furthermore, longer days allow for increased
photosynthetic activity allowing for an increase in phytoplankton blooms. While often more
problematic in the summer months, algal blooms are less common in the fall and winter when
water temperature decreases. High levels of chlorophyll-a and nutrients along with increases in
pH and turbidity may indicate the presence of an algal bloom. Throughout the course of this
study, pH values were found to be within acceptable ranges as were turbidity values. The lack of
elevated pH and turbidity along with generally low chlorophyll-a levels indicate that algal
blooms were generally not a problem. In fact, no algal blooms were identified within any
sampling site during the course of this study.
51
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
The chemical parameter nitrate/nitrite showed a marked difference between the tidal creeks
located in proximity to the Intracoastal Waterway and the creeks flowing into the Cape Fear
River. The nitrate/nitrite levels were approximately an order of magnitude lower in Pages Creek
and Futch Creek, the two creeks draining into the ICW. When excessive nitrate/nitrite enters
aquatic systems, algal growth otherwise limited by these nutrients becomes rapid and available
oxygen becomes consumed as these organisms die and decompose. While relatively higher
nitrate/nitrite levels have been identified within several watersheds, algal blooms have not been
problematic.
A number of sites contained dissolved oxygen levels below the State standard during the course
of this 12-month study. Two sites within Pages Creek, PC-BDDS and PC-BDUS, experienced
low dissolved oxygen during four (4) and five (5) sampling events, respectively. All five sites in
Futch Creek experienced low dissolved oxygen during July. Several of the sites within Futch
Creek also experienced low dissolved oxygen during the months between June and September
when the water temperature was the warmest. Of the creeks draining into the Cape Fear River,
Prince Georges Creek demonstrated the lowest dissolved oxygen most likely due to the physical
setting surrounding the creek. PG-CH and PG-NC demonstrated low dissolved oxygen seven (7)
and six (6) times of the twelve (12) times sampled, respectively. This portion of the creek is
characterized by a broad shallow bank in a swamp-like setting. It is typical of swamps to contain
low levels of dissolved oxygen and higher levels of pH, as observed. Therefore, the low
dissolved oxygen observed in Prince Georges Creek, particularly at PG-NC and PG-CH could be
regarded as a natural phenomenon.
High levels of Enterococci bacteria persisted within five (5) of the seven (7) watersheds
throughout the study period. Samples collected from Futch Creek and Lords Creek, however did
not contain levels of Enterococci above the State standard. Enterococci levels exceeded the
State standard in individual sampling sites within Prince Georges Creek, Smith Creek, Pages
Creek, Barnards Creek, and Motts Creek 33%, 35%, 33%, 42%, and 50% of the time,
respectively. The sites with the most frequent high concentrations of Enterococci bacteria were
located within the headwaters of Smith Creek (SC-CD and SCGR). These sites have
consistently contained high levels of Enterococci, however the source of the contamination
remains unclear at this time. Further investigation in this area is warranted.
Along with Enterococci, fecal coliform bacteria were tested within Pages Creek and Futch
Creek. A very high percentage of samples exceeded the single-sample NCDENR Shellfish
Sanitation standard of 14 CFU/100ml within these creeks. In fact, 40% of all samples collected
within Futch Creek exceeded this standard. Seventy-two percent (72%) of all samples collected
within Pages Creek also exceeded this standard.
Sources of nutrient and fecal bacteria pollutants can include fertilizers, septic system leachate,
leaking sewer mains, wild and domestic animal wastes, and overland runoff (Spivey, 2008). In
order to understand and manage fecal bacteria pollution in any body of water, one must first be
able to identify the source of the pollution (Kelsey et al. 2004). Previous studies have concluded
that increasing the amount of impervious surface coverage increases runoff, stream flow, and the
amount of pollutants reaching surface waters (Griffin et al, 1990; Schueler, 1994, Mallin, 2001).
Mallin et al. (2000) determined a strong correlation between impervious surface coverage and
52
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
fecal coliform bacteria levels in New Hanover County. Higher impervious surface coverage was
found to correlate with a higher geometric mean of fecal coliform bacteria within individual
watersheds. New Hanover County has experienced high rates of growth over the past several
decades. Along with population increases, the associated development of buildings, roadways,
and parking lots within the county has created increased areas of impervious surface coverage.
These pollutants include hydrocarbons, bacteria, and nutrients including nitrogen. Major sources
of anthropogenic nitrogen are fertilizer application, wastewater disposal and atmospheric
deposition (Howarth and Marino, 2006). The conversion of natural landscapes to impervious
surfaces removes the natural filtration capacity of the land, thereby facilitating increased
concentration of pollutants migrating directly into waterways. A recent assessment of the
impervious surface coverage within the watersheds of New Hanover County was performed
(Hume, 2008). Impervious surface percentages were determined to be 10.1% in Prince Georges
Creek watershed, 11.0% in Futch Creek watershed, 12.6% in Lords Creek watershed, in 13.5%
Motts Creek watershed, in 16.9% Barnards Creek watershed, 21.9% in Smith Creek watershed,
and 23.3% in Pages Creek watershed.
Another potential source of degraded water quality could originate from failing sewage and
septic systems. A source tracking study found bacteria originating from humans, ruminants, and
canines within six (6) tidal creeks in New Hanover County (Spivey, 2008). In the New Hanover
County Water Quality Monitoring Report 2008-2009, it was reported that human borne fecal
bacteria was also present within two (2) sites within Pages Creek. The source of this human-
borne bacteria may be indicative of either sewer-line problems, septic system failures, or a
general persistence in the bacteria itself (Spivey, 2008). New Hanover County and the Cape
Fear Public Utility Authority (CFPUA) have investigated the presence of abandoned septic tanks
and malfunctioning sewage lift stations in proximity to Pages Creek. These efforts were
inconclusive and high levels of Enterococci bacteria and fecal coliform occasionally persist
within these sites. As mentioned above, high levels of Enterococci bacteria have been identified
within the headwaters of Smith Creek and additional investigation to determine the cause is
recommended.
Failing sewage infrastructure may have contributed to declining water quality within several of
the County’s watersheds over recent years. Between June 2010 and May 2011, the CFPUA
reported a total of twenty-two (22) sewage spills within New Hanover County. During this time
period a total of 279,744 gallons were spilled with 272,210 gallons reaching surface waters
(Ricks, pers. comm.). These sewage spills were reported in two (2) of the seven (7) creeks
monitored in this study. One spill occurred in Pages Creek with 7,525 gallons reaching the
surface waters. A relatively large spill of 120,000 gallons flowed into Smith Creek on June 2,
2010. An additional 5,176 gallons was spilled at the same location several weeks later.
Subsequent to those events, an unrelated spill entailing 23,400 gallons entered Smith Creek
following a break in a force main at the James A. Loughlin wastewater treatment plant (Ricks,
pers. comm.). As noted above, several of the sites monitored within Smith Creek exceeded the
State standard for Enterococci on a regular basis, however these sites are located upstream from
the sewer spills. Two (2) of the three (3) sites monitored within Pages Creek exceeded the
standard for both fecal coliform and Enterococci bacteria on a regular basis as well. Although
sampling was not conducted immediately following these spills, it is possible that the bacteria
released into the creeks settled into the sediments where they persisted over time.
53
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Four (4) of the twenty-two (22) spills reported between June 2010 and May 2011 were attributed
by material (including grease, paper, and baby wipes) clogged in sewer lines. Seven (7) spills
were attributed to equipment or pipe failures. The majority of the spills, however, were caused
by severe natural conditions when heavy rains caused the system to overfill. The CFPUA is
engaged in a number of sewer infrastructure improvement projects along the Ogden interceptor
and other locations to help resolve these issues. In order to minimize future spills, the CPFUA
has initiated a public awareness campaign focused on educating its customers on what materials,
if flushed into a toilet, could be problematic to the wastewater infrastructure.
54
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
LITERATURE CITED
Grizzard, T.J., Randall, C.W., Helsel, D.R., and Hartigan, J.P. 1980. Analysis of non-point
pollution export from small catchments. Journal of Water Pollution Control Federation, 52:
780-790.
Howarth, R.W. and Marino, R. 2006. Nitrogen as the limiting nutrient for eutrophication in
coastal marine ecosystems: Evolving views over three decades. Limnology and Oceanography,
51: 364-376.
Hume, A. 2008. Determination of Impervious Surface in New Hanover County, North Carolina.
Report submitted to New Hanover County. Wilmington, North Carolina.
Jeng, J.G., Bradford, H, and Englande, A.J. 2004. "Comparison of E. coli, enterococci, and fecal
coliform as indicators for brackish water quality assessment". Water Environmental Research.
76: 245–55.
Kelsey, H., Porter, D.E, Scott, G., Neet, M., and White, D. 2004. Using geographic information
systems and regression analysis to evaluate relationships between land use and fecal coliform
bacterial pollution. Journal of Experimental Marine Biology and Ecology. 298:197-209.
Kwak, T.J. and Zedler, J.B. 1997. Food web analysis of southern California coastal wetlands
using multiple stable isotopes. Oecologia 110: 262–277.
Mallin, M.A.; Williams, K.E.; Esham, C.E.; and Lowe, P.R., 2000. Effect of human
development on bacteriological water quality in coastal watersheds. Ecological Applications
10:1047-1056.
Mallin, M.A., Ensign, S.H., McIver, M.R., Shank, G.C., and Fowler, P.K. 2001. Demographic,
landscape, and meteorological factors controlling the microbial pollution of coastal waters.
Hydrobiologia. 460: 185-193.
Mallin, M.A., 2010. University of North Carolina at Wilmington, Aquatic Ecologist. Personal
communication regarding findings of water samples obtained within PG-NC.
Odum, W.E., Smith, T.J., Hoover, J.K., and McIvor, C.C. 1984. The Ecology of Tidal
Freshwater Marshes of the United States East Coast: A Community Profile. , U.S. Fish and
Wildlife Service FWS/OBS-83/17, 177 pp.
Ricks, C., 2011. Cape Fear Public Utility Authority. Personal communication regarding sewage
spills in New Hanover County.
Schueler, T., 1994. The importance of imperviousness. Water Protection Technology. 1: 100-
111.
55
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Spivey, 2008. The use of PCR and T-RFLP as a means of identifying sources of fecal bacteria
pollution in the tidal creeks of New Hanover County, North Carolina. Masters Thesis.
University of North Carolina at Wilmington. 54pp.
U.S. Census Bureau, 2006 Population Estimates, Census 2000, 1990 Census
U.S. Environmental Protection Agency. 1984. Health effects criteria for fresh recreational
waters. EPA-600/1-84-004, U.S. Environmental Protection Agency, Washington, D.C.
U.S. Environmental Protection Agency. 1986. Ambient Water Quality Criteria for Bacteria-
1986. EPA-440/5/84-002, U.S. Environmental Protection Agency, Washington, D.C.