2009-2010 Final ReportCOASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
NEW HANOVER COUNTY WATER QUALITY MONITORING PROGRAM
2009-2010
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., 2010. New Hanover County Water Quality Monitoring
Program: 2009-2010 Final Report. New Hanover County, North Carolina: Coastal Planning &
Engineering of North Carolina, Inc. 47p.
July 2010
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COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
EXECUTIVE SUMMARY
This report represents the June 2009 through May 2010 results of the New Hanover County
Water Quality Monitoring Program. 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 in a number of these watersheds. All
watersheds were rated as “poor” with the exception of Futch Creek, which contained “good”
levels. 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 POOR POOR POOR POOR POOR
Fecal Coliform N/A POOR N/A N/A POOR N/A N/A
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COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
NEW HANOVER COUNTY WATER QUALITY MONITORING PROGRAM
FINAL REPORT
Table of Contents
Introduction ........................................................................................................................................1
Parameters .......................................................................................................................................4
Standards .........................................................................................................................................6
Methods..............................................................................................................................................8
Physical Parameters ........................................................................................................................9
Chemical and Biological Parameters ..............................................................................................9
Results ................................................................................................................................................9
Rating System .................................................................................................................................9
Barnards Creek ................................................................................................................................10
Futch Creek .....................................................................................................................................13
Lords Creek .....................................................................................................................................17
Motts Creek .....................................................................................................................................20
Pages Creek .....................................................................................................................................24
Prince Georges ................................................................................................................................28
Smith Creek ....................................................................................................................................32
Comprehensive Rating by Watershed .............................................................................................37
Long Term Trends ..........................................................................................................................38
Discussion ..........................................................................................................................................43
Literature Cited ................................................................................................................................46
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 Dissolved Oxygen 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
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
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NEW HANOVER COUNTY WATER QUALITY MONITORING PROGRAM
FINAL REPORT
Table of Contents (cont'd)
List of Figures
Figure No.
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 ....................................................25
23 Dissolved Oxygen at PC-BDDS ........................................................................................26
24 Dissolved Oxygen at PC-BDUS ........................................................................................26
25 Dissolved Oxygen at PC-M ...............................................................................................27
26 Enterococci and Fecal Coliform at PC-BDDS ..................................................................27
27 Enterococci and Fecal Coliform at PC-BDUS ..................................................................27
28 Enterococci and Fecal Coliform at PC-M .........................................................................28
29 Water Quality Sites within the Prince Georges Creek Watershed .....................................29
30 Dissolved Oxygen at PG-CH .............................................................................................30
31 Dissolved Oxygen at PG-ML.............................................................................................30
32 Dissolved Oxygen at PG-NC .............................................................................................31
33 Enterococci at PG-CH .......................................................................................................31
34 Enterococci and Fecal Coliform at PG-ML .......................................................................31
35 Enterococci at PG-NC .......................................................................................................32
36 Water Quality Sites within the Smith Creek Watershed ....................................................33
37 Dissolved Oxygen at SC-23 ...............................................................................................34
38 Dissolved Oxygen at SC-CD .............................................................................................34
39 Dissolved Oxygen at SC-CH .............................................................................................35
40 Dissolved Oxygen at SC-GR .............................................................................................35
41 Dissolved Oxygen at SC-NK .............................................................................................35
42 Enterococci at SC-23 .........................................................................................................36
43 Enterococci at SC-CD ........................................................................................................36
44 Enterococci at SC-CH ........................................................................................................36
45 Enterococci at SC-GR ........................................................................................................37
46 Enterococci at SC-NK .......................................................................................................37
47 Long term dissolved oxygen data within Pages Creek ......................................................40
48 Long term dissolved oxygen data within Futch Creek ......................................................40
49 Long term dissolved oxygen data within Smith Creek ......................................................41
50 Long term turbidity data within Pages Creek ....................................................................41
51 Long term turbidity data within Futch Creek ....................................................................41
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NEW HANOVER COUNTY WATER QUALITY MONITORING PROGRAM
FINAL REPORT
Table of Contents (cont'd)
List of Figures
Figure No.
52 Long term turbidity data within Smith Creek ......................................................................... 42
53 Long term chlorophyll-a data within Pages Creek ........................................................................42
54 Long term chlorophyll-a data within Futch Creek .................................................................43
55 Long term chlorophyll-a data within Smith Creek ................................................................. 43
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
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 ....................................28
16 Mean values of select parameters from Prince Georges Creek .............................................30
17 Ratings of parameters within sampling stations within Prince Georges Creek .....................32
18 Mean values of select parameters from Smith Creek ............................................................34
19 Ratings of parameters within sampling stations within Smith Creek ....................................37
20 Ratings of parameters within each watershed ........................................................................38
21 Changes of ratings within watersheds since 2007 .................................................................38
22 Enterococci levels in select sites between Nov. 2007 and May 2010 ...................................39
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FINAL REPORT
Table of Contents (cont'd)
List of Appendices
Appendix No.
A Photographs of Sampling Sites
B Raw Data
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COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
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 beginning in November 2007. The information
presented in this report represents the results of this monitoring between the months of June 2009
and May 2010. 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.
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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
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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:
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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.
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.
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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.
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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.
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
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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
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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
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
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COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Hanover County. Sampling sites were accessed from land, generally near a bridge or culvert
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).
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.
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
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 2009 and May 2010. These results are
organized by watershed. All raw data, including parameters not summarized in this section, are
included in Appendix B.
Rating System
In order to provide a quick-glance assessment of the water quality within a particular sampling
station or watershed, the University of North Carolina at Wilmington (UNCW) has previously
employed a rating system for a number of parameters. This quantitative system assigns a rating
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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.
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 5.2 mg/l and 12.3 mg/l with a mean
value of 7.7 mg/l. 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 2.0 ug/l with a mean value of 0.9 ug/l at BC-CBR.
These values did not approach the 40ug/l standard.
Enterococci ranged between 64 CFU/100ml and 1,364 CFU/100ml with a geometric mean value
of 426 CFU/100ml, which is above the NCDENR standard of 500 CFU/100ml for Tier III waters
(Figure 4). Half of the samples (50%) exceeded this standard.
Nitrate/nitrite levels ranged between 0.01 mg/l and 0.15 mg/l with a mean of 0.11 mg/l.
Orthophosphate levels ranged between 0.01 mg/l and 0.02 mg/l with a mean of 0.01 mg/l.
Turbidity values were generally good ranging between 0 and 27 NTU with a mean value of 7
NTU. No observations exceeded the State standard of 50 NTU for C SW waters.
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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) 7 (0-27)
Dissolved Oxygen (mg/l) 7.8 (5.4-12.3)
Nitrate/Nitrite (mg/l) 0.11 (0.01-0.15)
Orthophosphate (mg/l) 0.01 (0.01-0.02)
Chlorophyll-a (ug/l) 0.9 (1.0-2.0)
Enterococci (#CFU/100ml)425 (64-1364)1
(1)Enterococci values expressed as geometric mean
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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
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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 3.9 mg/l and 10.1 mg/l with a mean
value of 6.6 mg/l (Figures 6 through 9).
Chlorophyll-a ranged between 1.0 ug/l and 15.0 ug/l with a mean value of 2.6 ug/l. None of
these values approached the 40ug/l Chlorophyll-a standard.
Enterococci ranged between 1 CFU/100ml and 9,000 CFU/100ml with a geometric mean value
of 18 CFU/100ml. All samples collected within the four (4) sampling locations on December 1,
2009 exceeded the NCDENR Enterococci standard of 500 CFU/100ml for Tier III waters. Aside
from those samples, no other exceedences were observed (Figures 10-13).
The geometric mean of fecal coliform in Futch Creek was 18 CFU with a range of 1 to 1,546
CFUs. This geometric mean was above the NCDENR Shellfish Sanitation single-sample
standard of 14 CFU/100ml. 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 0.08 mg/l with a mean of 0.02 mg/l.
Orthophosphate levels ranged between 0.01 mg/l and 0.04 mg/l with a mean of 0.01 mg/l.
Turbidity values were generally low ranging between 0 and 36 NTU with a mean value of 5
NTU. A total of 3 observations exceeded the State standard of 25 NTU for SA waters.
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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) 3 (0-17) 3 (0-15) 7 (0-36) 6 (0-31)
Dissolved
Oxygen (mg/l) 7.0 (4.4-10.1) 6.9 (4.4-10.1) 6.2 (3.4-10.4) 6.3 (3.3-9.8)
Nitrate/Nitrite
(mg/l) 0.01 (0.01-0.01)0.01 (0.01-0.01)0.02 (0.01-0.07) 0.02 (0.01-0.08)
Orthophosphate
(mg/l) 0.01 (0.01-0.01)0.01 (0.01-0.02)0.02 (0.01-0.04) 0.01 (0.01-0.03)
Chlorophyll-a
(ug/l) 2.0 (0.0-4.0) 2.0 (1.0-4.0) 3.9 (1.0-15.0) 2.6 (1.0-5.0)
Enterococci
(#CFU/100ml) 11 (1-728)1 10 (1-728)1 34 (5-9000)1 27 (5-3600)1
Fecal Coliform
(#CFU/100ml) 13 (1-310)1 10 (1-260)1 39 (5-1455)1 20 (1-1546)1
(1)Enterococci and Fecal Coliform values expressed as geometric mean
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Figure 6. Dissolved Oxygen at FC-4
Figure 7. Dissolved Oxygen at FC-6
Figure 8. Dissolved Oxygen at FC-13
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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
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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 GOOD FAIR POOR POOR
Chlorophyll-a GOOD GOOD GOOD GOOD
Enterococci GOOD GOOD GOOD GOOD
Fecal Coliform POOR FAIR POOR POOR
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
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protection designation. Sampling was conducted at one (1) site (LC-RR) within the Lords Creek
watershed (Figure 14). Mean values and ratings from this site are presented in Tables 10 and 11.
Surface dissolved oxygen LC-RR ranged between 3.4 mg/l and 12.1 mg/l with a mean value of
7.7 mg/l. With the exception of the data collected in September 2009, these 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 26.0 ug/l with a mean value of 14.3 ug/l. Samples
obtained in August 2009 exceeded the State standard of 40ug/l for Chlorophyll-a.
Enterococci ranged between 5 CFU/100ml and 470 CFU/100ml with a geometric mean value of
58 CFU/100ml. No individual samples contained high levels of Enterococci beyond the
NCDENR standard of 500 CFU/100ml for Tier III waters (Figure 16).
Nitrate/nitrite levels ranged between 0.01 mg/l and 0.51 mg/l with a mean of 0.19 mg/l.
Orthophosphate levels ranged between 0.01 mg/l and 0.10 mg/l with a mean of 0.02mg/l.
Turbidity values were generally moderate ranging between 4 and 37 NTU with a mean value of
14 NTU. No observations exceeded the State standard of 50 NTU for C Sw waters in Lords
Creek during the study period.
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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) 14 (4-37)
Dissolved Oxygen (mg/l) 7.7 (3.4-12.1)
Nitrate/Nitrite (mg/l) 0.19 (0.01-0.51)
Orthophosphate (mg/l) 0.02 (0.01-0.10)
Chlorophyll-a (ug/l) 14.3 (1.0-26.0)
Enterococci (#CFU/100ml)58 (5-470)1
(1)Enterococci values expressed as geometric mean
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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
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
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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). The select results from these
individual stations are presented in Figures 18 through 21 and Tables 12 and 13.
Surface dissolved oxygen within Motts Creek ranged between 1.6 mg/l and 12.3 mg/l with a
mean value of 6.9 mg/l (Figures 18 and 19).
Chlorophyll-a ranged between 0.0 ug/l and 7.0 ug/l with a mean value of 2.0 ug/l. These values
did not approach the 40ug/l standard.
Enterococci ranged between 10 CFU/100ml and 24,000 CFU/100ml with a geometric mean
value of 455 CFU/100ml. 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 0.01 mg/l and 0.28 mg/l with a mean of 0.11 mg/l.
Orthophosphate levels ranged between 0.01 mg/l and 0.08 mg/l with a mean of 0.02 mg/l.
Turbidity values were generally good ranging between 2 and 30 NTU with a mean value of 11
NTU. No turbidity observations exceeded the State standard of 50 NTU for C Sw waters.
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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) 11 (2-30) 10 (3-20)
Dissolved Oxygen (mg/l) 6.8 (1.6-12.9) 6.9 (1.9-12.3)
Nitrate/Nitrite (mg/l) 0.1 (0.01-0.25) 0.12 (0.01-0.28)
Orthophosphate (mg/l) 0.02 (0.01-0.06) 0.03 (0.01-0.08)
Chlorophyll-a (ug/l) 2.3 (0.0-7.0) 1.8 (0.0-6.0)
Enterococci (#CFU/100ml)327 (10-15000)1 634 (55-24000)1
(1)Enterococci values expressed as geometric mean
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Figure 18. Dissolved Oxygen at MOT-CBR
Figure 19. Dissolved Oxygen at MOT-ND
Figure 20. Enterococci at MOT-CBR
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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 FAIR GOOD
Chlorophyll-a GOOD GOOD
Enterococci POOR POOR
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). Mean values and
ratings from all individual sites are presented in Tables 14 and 15.
Surface dissolved oxygen within Pages Creek ranged between 3.5 mg/l and 10.4 mg/l with a
mean value of 6.6 mg/l. 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 1.0 ug/l and 69.0 ug/l with a mean value of 6.3 ug/l. One sample
collected from PC-BDUS, exceeded the State standard of 40 ug/l for Chlorophyll-a.
Enterococci ranged between 4 CFU/100ml and 26,000 CFU/100ml with a geometric mean value
of 185 CFU/100ml (Figures 26 through 28). While samples collected from PC-M did not
contain high levels of Enterococci, five (5) and seven (7) samples from PC-BDDS and PC-
BDUS, respectively, contained levels higher than the NCDENR standards.
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Fecal coliform levels ranged between 1 CFU/100ml and 9,000 CFU/100ml with a geometric
mean of 160 CFU/100ml. 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
PC-BDUS. This standard was breached at PC-M on five (5) occasions (Figures 26 through 28).
Sixty-nine percent (69%) 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 0.08 mg/l with a mean of 0.02 mg/l.
Orthophosphate levels ranged between 0.01 mg/l and 0.23 mg/l with a mean of 0.03 mg/l.
Turbidity values were generally good ranging between 0 and 24 NTU with a mean value of 7
NTU. None of the observed turbidity values exceeded the State standard of 25 NTU for class SA
waters.
Figure 22. Water Quality Sites within the Pages Creek Watershed
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Table 14. Mean values of select parameters from Pages Creek. Range in parentheses.
Parameter PC-BDUS PC-BDDS PC-M
Turbidity (NTU) 9 (0-24) 7 (0-23) 5 (0-22)
Dissolved Oxygen (mg/l) 6.5 (3.5-10.4) 6.5 (3.6-10.2) 7.0 (5.1-10.2)
Nitrate/Nitrite (mg/l) 0.02 (0.01-0.05) 0.02 (0.01-0.08) 0.01 (0.01-0.01)
Orthophosphate (mg/l) 0.06 (0.02-0.23) 0.02 (0.01-0.04) 0.01 (0.01-0.02)
Chlorophyll-a (ug/l) 9.3 (1.0-69.0) 6.8 (1.0-24.0) 2.9 (1.0-5.0)
Enterococci (#CFU/100ml) 889 (109-19000)1 356 (18-26,000)1 20 (4-480)1
Fecal Coliform
(#CFU/100ml) 310 (73-8000)1 380 (18-9,000)1 12 (1-390)1
(1)Enterococci and Fecal Coliform values expressed as geometric mean
Figure 23. Dissolved Oxygen at PC-BDDS
Figure 24. Dissolved Oxygen at PC-BDUS
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Figure 25. Dissolved Oxygen at PC-M
Figure 26. Enterococci and Fecal Coliform at PC-BDDS
Figure 27. Enterococci and Fecal Coliform at PC-BDUS
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Figure 28. Enterococci and Fecal Coliform at PC-M
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 GOOD
Chlorophyll-a GOOD GOOD GOOD
Enterococci POOR POOR GOOD
Fecal Coliform POOR POOR POOR
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). Mean values and ratings from all individual sites are presented in Tables
16 and 17.
Surface dissolved oxygen within Prince Georges Creek ranged between 0.6 mg/l and 12.6 mg/l
with a mean value of 5.1 mg/l. Surface dissolved oxygen values at PG-CH and PG-NC were
below the State standard of 4.0 mg/l for C Sw during six (6) sampling events each, while PG-ML
was below the standard on five (5) occasions (Figures 30 through 32).
Chlorophyll-a ranged between 00. ug/l and 20.0 ug/l with a mean value of 2.8 ug/l. These values
did not exceed the 40ug/l standard.
Enterococci ranged between 5 CFU/100ml and 47,000 CFU/100ml with a geometric mean value
of 327 CFU/100ml. During this study, four (4) and seven (7) samples from PG-CH and PG-ML,
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respectively, contained Enterococci levels above the NCDENR standard of 500 CFU/100ml for
Tier III waters. Two (2) 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 0.50 mg/l with a mean of 0.11 mg/l.
Orthophosphate levels ranged between 0.01 mg/l and 0.05 mg/l with a mean of 0.02 mg/l.
Turbidity values were generally good ranging between 0 and 34 NTU with a mean value of 6
NTU. No observed turbidity values exceeded the State standard of 50 NTU for C Sw waters.
Despite relatively low turbidity levels, the surface water at PG-NC appeared uncharacteristically
discolored during the April and May 2010 sampling events. Water samples were examined by
UNCW researchers and found to contain high levels of fungal hyphae, protozoans, and
Euglenophyta algae. Euglenoids are considered to be characteristic of polluted water (Mallin,
pers. comm.).
Figure 29. Water Quality Sites within the Prince Georges Creek Watershed
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Table 16. Mean values of select parameters from Prince Georges Creek. Range in
parentheses.
Parameter PG-CH PG-ML PG-NC
Turbidity (NTU) 5 (0-34) 3 (0-11) 10 (0-27)
Dissolved Oxygen (mg/l) 5.0 (0.9-12.4) 5.9 (3.2-12.6) 4.4 (0.6-12.0)
Nitrate/Nitrite (mg/l) 0.11 (0.01-0.26) 0.11 (0.01-0.29) 0.12 (0.01-0.50)
Orthophosphate (mg/l) 0.02 (0.01-0.05) 0.04 (0.02-0.05) 0.01 (0.01-0.03)
Chlorophyll-a (ug/l) 1.9 (0.0-5.0) 2.8 (0.0-13.0) 3.6 (0.0-20.0)
Enterococci (#CFU/100ml) 370 (37-16,000)1 671 (208-1,910)1 140 (5-47,000)1
(1)Enterococci values expressed as geometric mean
Figure 30. Dissolved Oxygen at PG-CH
Figure 31. Dissolved Oxygen at PG-ML
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Figure 32. Dissolved Oxygen at PG-NC
Figure 33. Enterococci at PG-CH
Figure 34. Enterococci and Fecal Coliform at PG-ML
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Figure 35. Enterococci at PG-NC
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 POOR POOR
Chlorophyll-a GOOD GOOD GOOD
Enterococci POOR POOR FAIR
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). Mean values and
ratings from all individual sites are presented in Tables 18 and 19.
Surface dissolved oxygen within the creek ranged between 3.8 mg/l and 13.5 mg/l with a mean
value of 8.0 mg/l. With the exception of one observation from SC-NK August 2009, 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 1.0 ug/l and 26.0 ug/l with a mean value of 5.0 ug/l. All samples
were within the acceptable range.
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Enterococci ranged between 10 CFU/100ml and 57,000 CFU/100ml with a geometric mean
value of 593 CFU/100ml. A number of samples exceeded the NCDENR standard of 500
CFU/100ml for Tier III waters including two (2) from SC-23, ten (10) from SC-CD, eight (8)
from SC-GR, and three (3) from SC-CH. Seven (7) 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 0.72 mg/l with a mean of 0.16 mg/l.
Orthophosphate levels ranged between 0.01 mg/l and 0.10mg/l with a mean of 0.03 mg/l.
Turbidity values were generally good ranging between 0 and 118 NTU with a mean value of 11
NTU. Two (2) turbidity values from SC-CD exceeded the State standard of 50 NTU for SW
class C waters.
Figure 36. Water Quality Sites within the Smith Creek Watershed
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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) 11 (4.0-32.0) 19 (0.0-118.0) 15 (2.0-33.0) 6 (0.0-23.0) 5 (0.0-21.0)
Dissolved
Oxygen (mg/l) 8.4 (4.5-13.4) 8.9 (6.2-13.4) 7.1 (4.1-13.5) 8.9 (5.6-12.6) 6.8 (3.8-12.5)
Nitrate/Nitrite
(mg/l) 0.17 (0.01-0.37) 0.08 (0.01-0.16) 0.28 (0.04-0.72) 0.13 (0.01-0.49) 0.14 (0.01-.038)
Orthophosphat
e (mg/l) 0.05 (0.03-0.08) 0.02 (0.01-0.04) 0.06 (0.04-0.08) 0.02 (0.01-0.10) 0.02 (0.01-0.05)
Chlorophyll-a
(ug/l) 9.8 (1.0-26.0) 4.8 (1.0-15.0) 4.1 (1.0-11.0) 2.2 (1.0-10.0) 3.9 (1.0-10.0)
Enterococci
(#CFU/100ml) 210 (10-39,000)1 2,084 (64-19,000)1 140 (19-57,000)1 1,106 (220-
23,000)1
1,089 (118-
38,000)1
(1)Enterococci values expressed as geometric mean
Figure 37. Dissolved Oxygen at SC-23
Figure 38. Dissolved Oxygen at SC-CD
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Figure 39. Dissolved Oxygen at SC-CH
Figure 40. Dissolved Oxygen at SC-GR
Figure 41. Dissolved Oxygen at SC-NK
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COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
Figure 42. Enterococci at SC-23
Figure 43. Enterococci at SC-CD
Figure 44. Enterococci at SC-CH
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Figure 45. Enterococci at SC-GR
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 FAIR POOR FAIR POOR POOR
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 has also shown to contain good ratings; however dissolved oxygen was shown to be
“fair” while fecal coliform was determined to be “poor”. Both Lords Creek and Motts Creek
were deemed “good” for all parameters with the exception of “poor” for Enterococci. Pages
Creek also demonstrated “good” ratings for turbidity Chlorophyll-a, however dissolved oxygen,
fecal coliform, and Enterococci were “poor”. Similar to Pages Creek, Prince Georges Creek had
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“good” ratings for turbidity and Chlorophyll-a and “poor” ratings for dissolved oxygen and
Enterococci. Smith Creek had “good” water quality for all parameters with the exception of
Enterococci, which was rated as “poor”.
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 POOR POOR POOR POOR POOR
Fecal Coliform N/A POOR N/A N/A POOR N/A N/A
Long Term Trends
The rating system, based upon the number of samples exceeding State Standards, has been
utilized to assess the “state” of the watersheds on an annual basis since the release of the 2008
Final Report. Since that time, the condition of several parameters has changed within select
watersheds indicating emerging long term trends. Table 21 depicts these net changes since that
time. A “+1” was ascribed if the parameter improved by a magnitude of one rating (i.e. from
“fair” to “good”). If the magnitude of change increased by a magnitude of two ratings (i.e. from
“poor” to “good”), the parameter was ascribe “+2”. A negative change (decline in water quality)
was denoted with a negative sign. As depicted in Table 21, the turbidity ratings within all creeks
have maintained a “good” rating. Similarly, Chlorphyll-a ratings have been “good” for all creeks
with the exception of a change from “fair to “good” within Lords Creek. Motts Creek improved
its dissolved oxygen rating from “fair” to “good”, while Prince Georges Creek has declined in
dissolved oxygen levels (from “fair” to “poor”). The Enterococci levels have declined to “poor”
ratings for Barnards Creek, Lords Creek, Motts Creek, and Prince Georges Creek. Barnards
Creek and Motts Creek were rated as “good” in previous years while Lords Creek and Prince
Georges Creek were formerly deemed “fair”. No changes of fecal coliform bacteria levels were
observed within Futch Creek and Pages Creek (the only watersheds monitored for fecal
coliform).
Table 21. Changes of ratings within watersheds since 2007.
Parameter Barnards
Creek
Futch
Creek
Lords
Creek
Motts
Creek
Pages
Creek
Prince
Georges
Creek
Smith
Creek
Turbidity - - - - - - -
Dissolved Oxygen - - - +1 - -1 -
Chlorophyll-a - - +1 - - - -
Enterococci -2 - -1 -2 - -1 -
Fecal Coliform N/A - N/A N/A - N/A N/A
In light of the apparent long term decline in water quality in terms of Enterococci levels within a
number of the watersheds assessed, a closer examination of the results from individual sites was
conducted. Table 22 depicts the long term results (since November of 2007) of Enterococci
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COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
samples within the ten individual sites containing the most violations of the State standard.
Highlighted cells represent sample results which exceeded the State standard for Enterococci.
The site exceeding the standard most often was SC-CD (Smith Creek at Candlewood Drive).
This site exceeded the standard eighty-one (81%) of the time. Other sites exceeded this standard
29-52% of the times sampled.
Table 22. Enterococci levels in select sites between Nov. 2007 and May 2010.
Date SC-CD MOT-ND PC-BDDS PC-BDUS SC-GR BC-CBR PG-ML MOT-CBR SC-NK PG-CH
Nov. 2007 517 819 548 135 250 88 378 56 99 281
Dec. 2007 1210 1414 727 517 139 43 57 10 238 135
Jan. 2008 41 129 238 133 53 56 1210 135 122 75
Feb. 2008 703 155 637 1542 345 122 52 171 860 30
March 2008 708 272 20 30 275 145 187 31 41 52
April 2008 663 142 3873 1935 146 63 122 663 121 107
May 2008 384 262 331 160 435 548 1106 75 7701 2247
June 2008 2010 275 41 30 96 134 201 144 41 109
July 2008 1700 201 15 350 290 800 480 128 91 210
Aug. 2008 109 275 208 46 1637 728 1182 819 127 819
Sept. 2008 728 546 19 109 163 510 10 310 154 290
Oct. 2008 1182 1455 745 195 1455 350 163 280 118 10
Nov. 2008 4700 910 728 64 5900 2300 3000 2800 2000 1546
Dec.2008 280 2600 560 91 290 1000 190 1728 91 364
Jan. 2009 7000 1091 819 530 6000 818 637 580 364 1182
Feb. 2009 1091 273 637 590 540 270 240 154 181 82
March 2009 1546 330 270 109 230 210 250 240 200 37
April 2009 630 1091 28 46 600 145 154 260 55 73
May 2009 21000 1728 637 60000 4000 1273 2800 2800 728 200
June 2009 4300 24000 25000 2100 3200 1160 1637 15000 290 1637
July 2009 18000 3900 1182 8000 23000 1364 1910 3300 38000 16000
Aug. 2009 19000 330 18 500 880 470 920 590 4200 96
Sept. 2009 2546 1000 235 819 480 560 1819 910 2000 1819
Oct. 2009 4600 637 280 4400 530 64 220 300 510 470
Nov. 2009 2400 210 118 819 1182 181 1455 109 400 1273
Dec. 2009 1546 595 26000 19000 5400 430 510 220 1819 728
Jan. 2010 54 910 19 388 220 637 1091 10 118 55
Feb. 2010 1273 290 100 230 380 1091 390 181 4900 109
March 2010 109 82 910 109 440 181 300 19 370 55
April 2010 1182 55 610 230 530 260 370 430 260 37
May 2010 10000 1455 37 230 1637 520 208 520 1455 270
% Above
Standard 81% 52% 48% 48% 48% 45% 42% 36% 36% 29%
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Geometric
Mean 1257 541 285 388 645 331 401 272 390 227
Std. Dev. 5691 4251 6283 11125 4276 509 798 2727 6863 2855
Long-term water quality monitoring data from select sites and watersheds was mined from the
University of North Carolina at Wilmington to determine quantitative changes over time. Data
was not available from all currently monitored stations; therefore this analysis was performed
only for the stations which spanned the time period between 2004 and 2010. These included
samples acquired from Smith Creek, Futch Creek, and Pages Creek. Figures 47 through 49
depicts the average level of dissolved oxygen within these creeks since 2004. As illustrated in
these figures, the dissolved oxygen levels during the 2007 sampling period markedly declined
within all three watersheds.
Figure 47- Long term dissolved oxygen data within Pages Creek
Figure 48- Long term dissolved oxygen data within Futch Creek
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Figure 49- Long term dissolved oxygen data within Smith Creek
Figures 50 through 52 depicts the trend of turbidity within Pages Creek, Futch Creek, and Smith
Creek. As shown below, turbidity displayed an increase in magnitude during 2007.
Figure 50- Long term turbidity data within Pages Creek
Figure 51- Long term turbidity data within Futch Creek
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Figure 52- Long term turbidity data within Smith Creek
Chlorophyll-a levels within Pages Creek have increased since 2004 reaching an annual
maximum in 2008 (Figure 53). The chlorophyll-a levels in Futch Creek and Smith Creek
reached annual maximums in 2007 (Figures 54 and 55).
Figure 53- Long term chlorophyll-a data within Pages Creek
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Figure 54- Long term chlorophyll-a data within Futch Creek
Figure 55- Long term chlorophyll-a 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). 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.
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Typically, water quality degrades as the water warms and oxygen is not as readily dissolved in
the water column. 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 (5.9-9.0) as were turbidity values (with the exception of two individual
samples). The lack of elevated pH and turbidity along with generally low chlorophyll-a levels
indicate that algal blooms were generally not a problem.
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. Further study is required to determine
the cause of this sharp difference in nitrate/nitrite levels within these creeks.
Dissolved oxygen levels at a number of sites were below the State standard of 5.0 ml/l in SA
waters and 4.0 mg/l in C Sw waters. Two sites within Pages Creek, PC-BDDS and PC-BDUS,
experienced low dissolved oxygen during five (5) sampling events each. All five sites in Futch
Creek experienced low dissolved oxygen during August. 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-NC and PG-CH demonstrated low dissolved oxygen six (6) times of
the twelve (12) times sampled. 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 all watersheds throughout the study period,
with the exception of Lords Creek. Enterococci levels exceeded the State standard in individual
sampling sites within Prince Georges Creek, Smith Creek, Pages Creek, Barnards Creek, Futch
Creek, and Motts Creek 39%, 50%, 36%, 50%, 8%, and 46% of the time, respectively. 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, 42% of all samples collected within
Futch Creek exceeded this standard. Eighty-one percent (81%) 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
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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 persist within these sites.
Failing sewage infrastructure may have contributed to declining water quality within several of
the County’s watersheds over recent years. Between June 2009 and June 2010 alone, the
CFPUA reported a total of twenty-five (25) sewage spills within New Hanover County. A total
of 145,011 gallons were spilled during these events with 132,155 gallons reaching surface waters
(Ricks, pers. comm.). A relatively large spill into Smith Creek occurred on June 2, 2010 and
accounted for 120,000 gallons of the spill total for the year. As noted above in Table 22, three
(3) of the five (5) sites monitored within Smith Creek exceeded the State standard for
Enterococci on a regular basis. Thirteen (13) of the twenty-five (25) spills reported between
June 2009 and June 2010 were attributed by material (including grease, paper, and baby wipes)
clogged in sewer lines. The remaining twelve (12) spills were attributed to pipe failures, power
failures, and severe natural conditions. 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.
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