HomeMy WebLinkAbout2024-2025 Final ReportCPE
NEW HANOVER COUNTY WATER QUALITY MONITORING PROGRAM
2024-2025
FINAL REPORT
Prepared by:
Coastal Protection Engineering of North Carolina, Inc.
Marine Scientist: Brad Rosov, M.Sc.
Prepared For:
New Hanover County, North Carolina
Recommended Citation: Rosov, B., 2025. New Hanover County Water Quality Monitoring Program: 2024-
2025 Final Report. New Hanover County, North Carolina: Coastal Protection Engineering of North
Carolina, Inc.
November 2025
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EXECUTIVE SUMMARY
This report represents the findings of the New Hanover County Water Quality Monitoring Program for the
period July 2024 through June 2025. The results and long-term trends presented in this report are
described from a watershed perspective. Since 2007 the county has partnered with Coastal Protection
Engineering of North Carolina, Inc. to test water quality within tidal creeks in New Hanover County. The
creeks monitored for the 2024-2025 program year include Barnards, Futch, Lords, Motts, Pages, Prince
George, Smith, and Island.
Across the eight creeks a total of 20 sampling sites are monitored monthly for physical, chemical, and
biological parameters that, collectively, help determine the overall water quality. The objective is to
evaluate the current parameters and monitor trends to identify any decline in water quality. In addition
to the quantitative sampling results, an assessment of the water quality is provided in qualitative terms
for each watershed. This assessment gives each parameter the rating of either “Good”, “Fair”, or “Poor”
depending on the percentage of samples that went above the State standard for turbidity, chlorophyll-a,
and Enterococci, or below the State standard for dissolved oxygen. If the recorded value of a parameter
was outside the acceptable range of the State standard less than 10% of the times sampled the watershed
received a “Good” rating, a “Fair” rating for 11%-25% of the times sampled, or a “Poor” rating for greater
than 25% of the sampling times. The chart below depicts the overall water quality for each parameter for
each creek based on the rating system described above.
Ratings by watershed during the 2024-2025 reporting period
Parameter Barnards
Creek
Futch
Creek
Island
Creek
Lords
Creek
Motts
Creek
Pages
Creek
Prince
George
Creek
Smith
Creek
Turbidity GOOD GOOD GOOD GOOD GOOD GOOD GOOD GOOD
Dissolved
Oxygen GOOD GOOD POOR GOOD GOOD GOOD POOR GOOD
Chlorophyll-a GOOD GOOD GOOD GOOD GOOD GOOD GOOD GOOD
Enterococci GOOD GOOD GOOD GOOD FAIR FAIR GOOD FAIR
General Trends & Observations
Dissolved oxygen, turbidity, and chlorophyll-a levels fluctuate on a seasonal basis where, typically, levels
decrease during the winter and increase during the summer. In general, while seasonal differences have
been observed over the years, turbidity and chlorophyll-a levels have remained relatively low within the
sampled creeks. Similarly, dissolved oxygen levels have not drastically changed from year to year.
However, three creeks (Futch Creek, Motts Creek, and Pages Creek) improve from “Fair” during the 2023-
2024 sampling period to “Good” in this 2024-2025 sampling period. The long-term data shows that the
dissolved oxygen levels at Barnards Creek, Lords Creek, and Smith Creek have generally maintained
“Good” levels of dissolved oxygen while Prince George Creek have maintained “Poor” dissolved oxygen
over time. Island Creek has only been monitored since 2021, but during that time frame, the creek has
also demonstrated “Poor” levels of dissolved oxygen. The low levels of dissolved oxygen within these two
creeks are likely due to their naturally slow water flow, which is more characteristic of swamp-like waters.
Slower moving waters typically contain lower dissolved oxygen levels. Meanwhile, Futch Creek and Motts
Creek have varied between “Good” and “Fair” since 2008.
Enterococci bacteria levels during the 2024-2025 sampling period remained the same as the previous
sampling period for six of the eight creeks included within the study (Barnards Creek, Futch Creek, Lords
Creek, Pages Creek, Smith Creek, and Island Creek). Meanwhile, Motts Creek improved from “Poor” to
“Fair” while Prince George Creek improved from “Fair” to “Good” over the same time period. Since 2019,
Barnard Creek, Futch Creek, and Lords Creek have contained relatively lower bacteria levels compared to
the other creeks. Island Creek has also consistently contained low levels of bacteria, however, as
previously noted, sampling within the creek only dates back to 2021.
In addition to water quality monitoring efforts within the network of tidal creeks, New Hanover County
began monthly monitoring at the lake at Airlie Gardens in 2015 due to concerns of noticeable algal blooms
that have been observed over the years. The lake drains directly into Bradley Creek, close to the Atlantic
Intracoastal Waterway (ICWW). Three sampling sites are maintained within the lake. They are located
where contributing water enters the lake (intake), in the middle of the lake, and in proximity to the outfall
where the water leaves the lake and enters Bradley Creek.
Since 2015, water quality monitoring results from within the lake at Airlie Gardens has shown that
dissolved oxygen also demonstrates seasonal trends- increasing during the warmer summer months and
decreasing during the colder winter months. In general, dissolved oxygen levels are consistently lower at
the sampling site located in proximity to the intake of runoff entering into the lake compared to the
sampling sites located within the mid-point of the lake and in proximity to the outfall near Bradley Creek.
Overall, there are no current concerns with the dissolved oxygen levels within the lake.
With the exception of this past sampling period, over the course of the study, the levels of the nutrient
Nitrite/Nitrate have generally been higher at the intake compared to the sampling site located at the
outfall of the lake. This trend was also observed with the nutrient orthophosphate during the first three
years of monitoring, however, over the past five years this trend has reversed, where orthophosphate
was lower at the intake and higher at the outfall of the lake (Figures 50 & 51). High concentrations of
orthophosphate and Nitrite/Nitrate can cause algae growth leading to algal blooms which can cause low
dissolved oxygen and a decline in overall water quality. Since monitoring began in 2015, there had been
an incremental trend of increasing amounts of orthophosphate through 2023. After declining significantly
during the 2023-2024 sampling period, the level has increased again this past year. A more in-depth
review of water quality for Airlie can be found in the Discussion section of this report.
Over the course of the first four years of monitoring within the lake, chlorophyll-a levels generally
increased. Since that time, levels have stabilized, however, higher levels have been observed at the
sampling sites located at the midpoint of the lake and in proximity to the outfall compared to the sampling
location adjacent to the intake into the lake. High levels of Chlorophyll-a can be indictive of the presence
of algal blooms.
Key Takeaways
• With few exceptions, Futch Creek, Lords Creek, and Island Creek have generally contained low
levels of enterococci over the entire course of the program.
• Several creeks have improved water quality in terms of enterococci bacteria over the years:
o At Barnards Creek, the percentage of samples exceeding the standard was 42% between
2008-2012. However, between 2013 to 2019, that percentage was reduced to an average
of approximately 15%. Between 2020 to present, not one sample exceeded the standard.
o At Motts Creek, 53% of samples exceeded the standard between 2008 to 2015. Since
2015, the percentage of samples exceeding the standard dropped to 19%.
o At Prince George Creek, 29% of samples collected between 2008 to 2017 exceeded the
standard. Between 2018 to Present, only 7% of samples exceeded the standard
o At Smith Creek, 31% of samples collected between 2008 to 2018 exceeded the standard.
Between 2019 to Present, only 8% of samples exceeded the standard.
• Since 2007 Pages Creek has continued to demonstrate elevated levels of enterococci bacteria
where an average of 34% of samples collected exceed the standard. Of the three sites monitored
in Pages Creek, the majority of the samples collected with elevated levels came from two sites
(PC-BDDS and PC-BDUS). It should be noted that the standards for PC-BDDS and PC-BDUS are
different. Parameter standards can be found in Appendix D.
o Since 2007 45% of the samples collected from PC-BDDS exceeded the standard for
enterococci (<500 CFU/100 ml) on an annual basis.
o Since 2007 53% of the samples collected from PC-BDUS exceeded the standard for
enterococci (<276 CFU/100 ml) on an annual basis. It should be noted that over the course
of the past three sampling periods, the annual average of exceedances dropped to 19%.
• With few exceptions Smith Creek and Lords Creek have generally contained adequate levels of
dissolved oxygen over the entire course of the program.
• Island Creek, Prince George Creek, and Pages Creek have experienced relatively low levels of
dissolved oxygen over time with 47%, 38%, and 21% of the samples below the standard,
respectively.
• Futch Creek dissolved oxygen levels have improved in recent years. Between 2008 to 2019, 20%
of samples contained dissolved oxygen levels below the standard. However, between 2020 to
2025, only 3% of samples were below that standard.
• Barnards Creek has had varying dissolved oxygen levels over time. While not one sample was
below the standard in 10 of the 18 years we’ve monitored, there were 4 years where at least 25%
of the samples were below the standard (2014, 2015, 2016, 2022).
• Motts Creek has demonstrated relatively stable levels of dissolved oxygen with approximately 9%
of the samples exceeding the standard over the entire course of the program.
Water Quality Management
In New Hanover County water quality has been an important issue at both the state and local level, and
the county has a rich history of research, education and testing that continues through the work of
multiple departments currently. While the primary focus of the New Hanover County Water Quality
Monitoring Program is to observe and track the trends of water quality parameters, other departments
such as Health and Human Services, Engineering, Soil and Water Conservation District, and Sustainability
are also involved in work that effect overall water quality. Those efforts are described in more detail in
Appendix C of this report.
In recent years, New Hanover County has advanced multiple initiatives to protect and improve water
quality in the Pages Creek watershed through coordinated efforts among the Soil & Water Conservation
District, Engineering Department, and Cape Fear Public Utility Authority (CFPUA). Projects include
installation of stormwater control measures, feasibility and sediment studies, culvert and sewer
infrastructure upgrades, and expanded watershed monitoring. The County continues to enforce
stormwater and erosion control standards, maintain proactive inspection and maintenance programs, and
collaborate with university researchers to identify sources of pollution and enhance long-term watershed
resilience.
TABLE OF CONTENTS
EXECUTIVE SUMMARY ....................................................................................................................... I
GENERAL TRENDS & OBSERVATIONS .................................................................................................................. I
KEY TAKEAWAYS ............................................................................................................................................ II
WATER QUALITY MANAGEMENT..................................................................................................................... IV
TABLE OF CONTENTS ...........................................................................................................................
INTRODUCTION .................................................................................................................................1
CREEK SUMMARIES ............................................................................................................................1
BARNARDS CREEK .......................................................................................................................................... 1
FUTCH CREEK ................................................................................................................................................ 4
ISLAND CREEK ............................................................................................................................................... 5
LORDS CREEK ................................................................................................................................................ 6
MOTTS CREEK ............................................................................................................................................... 7
PAGES CREEK ................................................................................................................................................ 8
PRINCE GEORGE CREEK .................................................................................................................................. 9
SMITH CREEK ................................................................................................................................................ 9
AIRLIE GARDENS ............................................................................................................................................ 4
DISCUSSION ..................................................................................................................................... 12
PARAMETERS .............................................................................................................................................. 13
AIRLIE GARDENS DISCUSSION ........................................................................................................................ 14
APPENDIX A: ADDITIONAL CREEK DATA ............................................................................................ 16
BARNARDS CREEK ........................................................................................................................................ 16
FUTCH CREEK .............................................................................................................................................. 18
ISLAND CREEK ............................................................................................................................................. 23
LORDS CREEK .............................................................................................................................................. 26
MOTTS CREEK ............................................................................................................................................. 28
PAGES CREEK .............................................................................................................................................. 31
PRINCE GEORGE .......................................................................................................................................... 35
SMITH CREEK .............................................................................................................................................. 39
AIRLIE GARDENS .......................................................................................................................................... 44
APPENDIX B: LONG TERM TRENDS .................................................................................................... 50
DISSOLVED OXYGEN ..................................................................................................................................... 50
TURBIDITY .................................................................................................................................................. 51
CHLOROPHYLL-A .......................................................................................................................................... 52
ENTEROCOCCI ............................................................................................................................................. 53
APPENDIX C ..................................................................................................................................... 55
WATER QUALITY MANAGEMENT.................................................................................................................... 55
APPENDIX D ..................................................................................................................................... 58
WATER CLASSIFICATIONS .............................................................................................................................. 58
PARAMETER DEFINITIONS ............................................................................................................................. 58
STANDARDS ................................................................................................................................................ 61
METHODS .................................................................................................................................................. 64
LITERATURE CITED ........................................................................................................................... 65
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INTRODUCTION
New Hanover County’s (NHC) location is unique since with the exception of the northeastern boundary,
it is surrounded by water on three sides: on the north and south by the Northeast Cape Fear River, on the
west by the Cape Fear River, and on the east by the Atlantic Ocean. It is primarily a coastal county
containing many creeks, streams, and water bodies that provide opportunities for a wide range of
recreational activities for thousands of local citizens and visiting tourists yearly. Due to its proximity to
the Atlantic Ocean and the Intracoastal Waterway, NHC’s tidal creeks are not only used for recreation but
are an important resource for the natural environment as they provide habitats for various plant and
animal species. 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). Therefore, protection of the water
quality within these creeks is a high priority for the county.
Water quality has been monitored in New Hanover County since the early 1970s by the State in efforts to
study the impacts of adjacent septic systems on water quality in tidal creeks. An increase in the closure of
tidal creeks for shellfishing became an early concern for the citizens of New Hanover County and was a
topic included in early land use plans. The ongoing water quality conversation within the community led
to several watershed plans and in 1993, New Hanover County and the City of Wilmington partnered with
the University of North Carolina Wilmington (UNCW) to conduct a long-standing water quality monitoring
program.
However, in November 2007, Coastal Protection Engineering of North Carolina, Inc. (CPE) began a
separate, monthly water quality monitoring program on behalf of New Hanover County for the tidal creeks
within the unincorporated parts of the County.
The information presented in this report focuses on the results of this monitoring from July 2023 to June
2024. The creeks included in this study are Pages and Futch, which drain into the Atlantic Intracoastal
Waterway (ICW), Island Creek, which drains into the Northeast Cape Fear River and Lords, Motts,
Barnards, Smith, and Prince George which drain into the Cape Fear River (Figure 1). In addition to the
continued sampling from the seven tidal creeks, three sampling sites from within Airlie Gardens have been
monitored since 2015.
The results described in this report represent the physical, biological, and chemical data collected monthly
from all sampling sites from July 2023 through June 2024. These results are organized by watershed
alphabetically, with the results of the eight tidal creeks presented first, followed by the results from Airlie
Gardens. Additional creek data, including parameters not summarized in this section, from the tidal creeks
sampling sites and the Airlie Garden sampling sites can be found in Appendix A.
Based on the raw data, a quantitative system assigns a rating of “Good”, “Fair”, or “Poor” to a sampling
station depending on the percentage of samples that went above the State standard for turbidity,
chlorophyll-a, Enterococci, or below the State standard for dissolved oxygen. If the recorded value of a
parameter went outside the acceptable range of the State standard less than 10% of the times sampled
the station will receive a “Good” rating, a “Fair” rating for 11%-25% of the times sampled, or a “Poor”
rating for greater than 25% of the sampling times. This general description is useful when looking at
trends from year to year and across the entire time frame of the program. Ratings for all parameters can
be found in the Discussion section below.
Figure 1: Watersheds Monitored
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CREEK SUMMARIES
Barnards Creek
• Location: South central New Hanover County
and a portion in the City of Wilmington. (Monkey
Junction, Echo Farms, Carriage Hills).
• 1 Sampling Location: BC-CBR
• Size: 4,234 Acres
• Drains To: Cape Fear River
• Land Use: Low and medium density residential,
commercial, and retail uses along Carolina Beach
Road, S. 17th Street, and S. College Road
Overall Assessment
No samples exceeded state standards for any parameter
this year including Enterococci in which levels were
generally lower compared to last year.
Annual Average
Exceedances Lifetime Past 5
Years
Dissolved oxygen (below 4) 1.0 < 1.0
Chlorophyll-a (above 40) < 1.0 < 1.0
Turbidity (above 50) < 1.0 0
Enterococci (above 500) 2.3 0
Parameter BC-CBR
Turbidity (NTU) Good (all sites)
Dissolved Oxygen Good (all sites)
Chlorophyll-a Good (all sites)
Enterococci Good (all sites)
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Futch Creek
• Location: Northeast New Hanover County and
a portion of Pender County (Porters Neck,
Scotts Hill).
• 4 Sampling Locations: FC-4, FC-6, FC-13,
FC-FOY
• Size: 3,429 Acres
• Drains To: Intracoastal Waterway
• Land Use: Low density residential and some
commercial/retail uses along U.S. 17.
Overall Assessment
Dissolved oxygen exceedances decreased compared to
last year with only one exceedance of enterococci and
chlorophyll-a for the year.
Annual Average
Exceedances Lifetime Past 5
Years
Dissolved oxygen (below 4) 7.1 2.0
Chlorophyll-a (above 40) < 1.0 < 1.0
Turbidity (above 50) 0 0
Enterococci (above 500) 1.5 < 1.0
Parameter FC-4, FC-6, FC-13, FC-FOY
Turbidity (NTU) Good (all sites)
Dissolved Oxygen Good (all sites)
Chlorophyll-a Good (all sites)
Enterococci Good (all sites)
4
Island Creek
• Location: Northeast New Hanover County and
portions of Pender County (Sidbury Road & Holly
Shelter Road).
• 2 Sampling Locations: IC-HS, IC-SID
• Size: 12,919 Acres
• Drains To: NE Cape Fear River
• Land Use: Mostly undeveloped, low density
residential.
*Monitoring in Island Creek began in 2021
Overall Assessment
Dissolved oxygen was rated poor with ten (10)
occurrences below the state standard. There no
occurrence of elevated chlorophyll-a, turbidity, or
enterococci for the year.
Annual Average
Exceedances Lifetime Past 5
Years
Dissolved oxygen (below 4) 9.6 9.6*
Chlorophyll-a (above 40) < 1.0 < 1.0*
Turbidity (above 50) 0 0*
Enterococci (above 500) < 1.0 < 1.0*
Parameter IC-HS, IC-SID
Turbidity (NTU) Good (all sites)
Dissolved Oxygen Poor (all sites)
Chlorophyll-a Good (all sites)
Enterococci Good (all sites)
Lords Creek
• Location: Southwest New Hanover County
(Veterans Park, River Road).
• 1 Sampling Location: LC-RR
• Size: 1,076 Acres
• Drains To: Cape Fear River
• Land Use: Low density residential and
commercial/retail uses along Carolina Beach
Road.
Overall Assessment
There was only one (1) exceedance of enterococci for the
year and no exceedances for the other parameters.
Annual Average
Exceedances Lifetime Past 5
Years
Dissolved oxygen (below 4) < 1.0 < 1.0
Chlorophyll-a (above 40) < 1.0 0
Turbidity (above 50) < 1.0 < 1.0
Enterococci (above 500) < 1.0 0
Parameter LC-RR
Turbidity (NTU) Good
Dissolved Oxygen Good
Chlorophyll-a Good
Enterococci Good
3
Motts Creek
• Location: South central New Hanover County
(Monkey Junction, Silver Lake, Piner Road).
• 2 Sampling Locations: MOT-ND, MOT-CBR
• Size: 2,906 Acres
• Drains To: Cape Fear River
• Land Use: Low to Moderate density residential
with commercial and retail along Carolina Beach
Road and S. College Road.
Overall Assessment
Enterococci levels were similar to last year with six (6) total
exceedances for the year. There were no exceedances in
the other parameters for the year.
Annual Average
Exceedances Lifetime Past 5
Years
Dissolved oxygen (below 4) 2.3 2
Chlorophyll-a (above 40) < 1.0 < 1.0
Turbidity (above 50) < 1.0 0
Enterococci (above 500) 8.4 4.6
Parameter MOT-CBR, MOT-ND
Turbidity (NTU) Good (all sites)
Dissolved Oxygen Good (all sites)
Chlorophyll-a Good (all sites)
Enterococci Good, Poor
Pages Creek
• Location: Northeastern New Hanover County.
(Middle Sound, Ogden, Porters Neck).
• 3 Sampling Locations:
PC-BDUS, PC-BDDS, PC-M
• Size: 4,124 Acres
• Drains To: Intracoastal Waterway
• Land Use: Low density residential and some
commercial/retail uses along U.S. 17.
Overall Assessment
Dissolved Oxygen levels were below state standards
three (3) times (PC-BDDS). Enterococci exceeded the
standard nine (9) times across both the PC-BDDS and PC-
BDUS sites. One (1) observation each of elevated
turbidity and chlorophyll-a was noted for the year.
Parameter PC-BDDS, PC-BDUS, PC-M
Turbidity (NTU) Good (all sites)
Dissolved Oxygen Fair, Good, Good
Chlorophyll-a Good (all sites)
Enterococci Poor, Poor, Good
Annual Average
Exceedances Lifetime Past 5
Years
Dissolved oxygen (below 4) 7.6 4.8
Chlorophyll-a (above 40) 1.0 1.0
Turbidity (above 50) 0 0
Enterococci (above 500) 12.1 9
Prince George Creek
• Location: North New Hanover County (Castle
Hayne).
• 4 Sampling Locations: PG-CH, PG-ML, PG-NC
• Size: 10,875 Acres
• Drains To: Northeast Cape Fear River
• Land Use: Low density residential, agricultural,
and some commercial/retail uses along Castle
Hayne Road and N. College Road.
Overall Assessment
Dissolved Oxygen was below state standards eighteen (18)
times this year. There were three (3) exceedances for
Enterococci. Only one (1) exceedance for chlorophyll-a and
no exceedances of turbidity for the year.
Annual Average
Exceedances Lifetime Past 5
Years
Dissolved oxygen (below 4) 14 16.6
Chlorophyll-a (above 40) < 1.0 < 1.0
Turbidity (above 50) < 1.0 0
Enterococci (above 500) 7 2.4
Parameter PG-CH, PG-ML, PG-NC
Turbidity (NTU) Good (all sites)
Dissolved Oxygen Poor (all sites)
Chlorophyll-a Good (all sites)
Enterococci Good (all sites)
Smith Creek
• Location: Central New Hanover County including
portions of City of Wilmington (Wrightsboro, ILM,
Kings Grant, Coastal Carolina).
• 4 Sampling Locations: SC-NK, SC-GR, SC-CD,
SC-23
• Size: 17,535 Acres
• Drains To: Cape Fear River
• Land Use: Moderate density residential within the
city, light industrial around the airport, some
agricultural along Kerr Avenue, and some
commercial/retail uses along U.S. 17.
Overall Assessment
Enterococci bacteria exceeded state standards six (6) times
for the year. Dissolved oxygen was below the state
standard three (3) times and one (1) exceedance of
chlorophyll-a.
Parameter SC-CH, SC-CD, SC-GR, SC-NK
Turbidity (NTU) Good (all sites)
Dissolved
Oxygen Fair, Good, Good, Good
Chlorophyll-a Good (all sites)
Enterococci Good, Fair, Good, Good
Annual Average
Exceedances Lifetime Past 5
Years
Dissolved oxygen (below 4) 3.6 3
Chlorophyll-a (above 40) < 1.0 < 1.0
Turbidity (above 50) < 1.0 < 1.0
Enterococci (above 500) 12.7 3.4
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Airlie Gardens
• Location: City of Wilmington.
• 3 Sampling Locations: AG-IN, AG-FD, AG-
OUT
• Size: 10 Acre Freshwater Lake
• Drains To: Bradley Creek
• Land Use: On a conservation site surrounded
by low density residential.
Year at a Glance
• 9 (nice) occurrences of dissolved oxygen below
State standard
• 12 (twelve) occurrences above State standard
for chlorophyll-a
• 0 (zero) occurrences above State standard for
turbidity
*Enterococci is not measured at Airlie Gardens
Overall Assessment
Exceedances for both dissolved oxygen and chlorophyll-a
decreased this year compared to last year.
Orthophosphate and Nitrate levels were moderate again
this year. Despite lower chlorophyll-a levels there were
confirmed algal blooms in the lake.
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DISCUSSION
Water quality is an important issue in the region since there are many economic and recreational
opportunities that are supported by the aquatic resources in and around these waterways. In New
Hanover County, different factors can affect water quality with a major one being land use. In more rural
parts of the county, agriculture and farming can introduce increased amounts of chemicals like those
found in fertilizer and bacteria from animal waste. Additionally, failing or poorly maintained septic
systems can increase bacteria in a watershed. In more urbanized areas, experts have identified
stormwater runoff created by increased impervious surface coverage (Mallin et al., 2000) as a reason for
increases in chemicals like those found in fertilizer for landscaped lawns, as well as bacteria from pet
waste. Like rural areas, urban areas can also see human bacteria introduced into nearby waterways if
there are deficiencies or leaks in the sanitary sewer system. Due to many of the contaminants found in
stormwater runoff and its ability to concentrate especially after rain events, adverse effects can be
imposed upon 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 steady growth and development over the past several decades
increasing in population by about forty percent from 2000 (160,307) to 2020 (225,702) according to the
United States Census Bureau. While long term monitoring suggests that development and continued
growth in New Hanover County may have altered water quality within its tidal creeks in the past, a more
recent assessment of the ratings for some water quality parameters as depicted in this report shows they
have seen improvements or remained steady over the past several years. This suggests that even though
the unincorporated portions of New Hanover County continue to build out, there are factors serving to
help minimize the impact on water quality. One factor may be the inclusion of state stormwater controls
required for all new development which aim to mitigate stormwater on site. These stormwater control
measures aim to reduce water quantity, which affects water quality. Additionally, in 2020 the county
created a stormwater services program to help maintain and improve drainage, primarily in areas
developed prior to state stormwater regulations. An increase in stormwater control measures can
contribute to overall water quality and mitigate the effects of stormwater runoff.
From a bacteria perspective, in 2017, the CFPUA completed work to provide the Marquis Hills subdivision
within the Motts Creek watershed with sewer service providing a more reliable way to treat sewage.
Additionally, the CFPUA, through their capital improvement plan, identifies and prioritizes projects to
upgrade aging infrastructure like pumpstations, and programs like “Find it and Fix it” to maintain the
integrity of the sewer system. For overall water quality, the county continues to work toward preventing
further deterioration and loss of public uses in surface water through initiatives such as the
implementation of best management practices (BMPs) and promoting low impact development. As
mentioned, the New Hanover County Stormwater Services Program continues to work on and has
completed numerous drainage improvement projects. With this in mind, it is important to continue to
monitor the water quality and assess the potential impacts to both human health and ecosystem function
as conditions change.
The long-term water quality monitoring results suggest that the seven creeks monitored since July 2008
have experienced good water quality in terms of turbidity and chlorophyll-a levels as does Island Creek,
which was included within the study in 2021. The parameter that has been problematic within several
creeks included in the study has been Enterococci bacteria. Of the 3,936 samples collected and analyzed
since July 2008, 796 samples (20%) have exceeded the State standard for this bacterium.
Parameters
Physical and biological water quality monitoring data have been collected at each of the tidal creek
sampling locations. 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 Enterococci, a fecal indicator for bacteria.
At the Airlie Gardens sampling locations, the same physical parameters were collected in addition to
chemical parameters including orthophosphate and nitrate/nitrite. Enterococci samples are not collected
at Airlie Gardens as it was determined at that time that bacterial contamination was not an issue.
Biological Parameter Discussion
Chlorophyll-a
Since water quality monitoring began in 2008, some trends have emerged. Typically, water quality
degrades as the water temperature increases and oxygen is not as readily dissolved in the water column.
This phenomenon has been observed while investigating the long-term trends of water quality for this
program. The dissolved oxygen along with chlorophyll-a and turbidity levels have generally increased
during warmer summer months. The longer summer days allow for increased photosynthetic activity
that, as a result, can lead to phytoplankton blooms. While often problematic in the summer months, algal
blooms are less common in the fall and winter when water temperatures decrease. 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 and turbidity measurements were generally found
to be within acceptable ranges while only four (4) chlorophyll-a samples exceeded the State standard
during the 2024-2025 monitoring period.
Dissolved Oxygen
In general, the dissolved oxygen within Barnards Creek, Lords Creek, Motts Creek, and Smith Creek has
been rated “Good” over the course of the entire program with few exceptions. Barnards Creek
experienced a decline in dissolved oxygen between 2014 and 2017, but, since that time, improved to
“Good” again over the seven of the past eight years. Futch Creek has maintained a “Fair” and “Good”
ratings over the course of ten and six sampling periods, respectively. Pages Creek has demonstrated
varying dissolved oxygen levels over time ranging from “Poor” to “Good” over the years and has been
deemed “Fair” during six of the past seven monitoring periods. Prince George Creek has demonstrated
the worst long-term dissolved oxygen levels compared to the other creeks in the study as it has been
designated as “Poor” fifteen of the seventeen-year study. Island Creek has only been monitored since
2021, but dissolved oxygen levels were deemed to be “Poor” three of the four sampling periods. It should
be noted that the slow-moving water and swamp-like features within portions of Prince George Creek and
Island Creek may help naturally facilitate these low dissolved oxygen levels.
Physical Parameter Discussion
Enterococci
While several creeks have exhibited relatively low levels of bacteria throughout the lifetime of the
program (namely Futch Creek, Lords Creek and Island Creek), other creeks have proven to show elevated
levels of Enterococci. Of the 3,936 samples collected and analyzed from all the monitoring sites since July
2008 (including those from Island Creek, which started in 2021), 796 samples (20%) have exceeded the
State standard for this bacterium. Specifically, Motts Creek has exceeded the standard 33% of the time
and at Pages Creek, the down-stream site (PC-BDDS) and up-stream site (PC-BDUS) exceeded the standard
45% and 53% of the time, respectively.
The Enterococci levels over the course of the first ten years of monitoring were relatively higher, overall,
compared to the levels observed since 2018. It should be noted, however, that no samples exceeded the
State Enterococci standard over the past two sampling periods from within Barnards Creek and Island
Creek Lords Creek and only one sample from within Futch Creek and Lords Creek over past two years.
At Motts Creek, the bacteria levels had moderated over recent years. Prior to the 2016-2017 sampling
effort, Motts Creek had consistently demonstrated “Poor” water quality in terms of bacterial
contamination with 50% of all samples collected during that timeframe exceeding the Enterococci
standard. Since that time, Motts Creek been rated as “Fair” the majority of the time. As mentioned above,
the overall improvement in Enterococci levels within the creek was most likely attributed to the transition
of residential homes with failing septic systems to the CFPUA’s sewer system in the Marquis Hills
community (located within the Motts Creek watershed). Between the 2016-2017 and 2024-2025 sampling
periods, the bacteria levels have generally been reduced with the number of exceedances around 18%
proving the effects of improving wastewater treatment measures. CFPUA has planned upgrades to the
wastewater infrastructure which may further improve overall water quality in the watershed. New
Hanover County in 2019 completed a drainage project to improve flow where data has shown a reduction
in the levels of bacteria and improvements in dissolved oxygen and chlorophyl-a.
Pages Creek continued to show elevated levels of Enterococci where nice (9) out of thirty-six (36) samples
(22%) exceeded the State standard over the course of the most recent study period. None of the samples
collected from the site at the mouth of Pages Creek (PC-M) exceeded the standard. Of the nine (9)
samples that exceeded the standard, five (5) were from the Pages Creek Down-Stream Site (PC-BDDS)
while four (4)) were from the Pages Creek Up-Stream site (PC-BDUS). As mentioned above, since 2008,
PC-BDDS and PC-BDUS exceeded the standard 45% and 53% of the time, respectively. However, over the
past 3 sampling periods, the percentage of exceedances at PC-BDUS has decreased to 19%.
Airlie Gardens Discussion
The results from monthly sampling over the past ten (10) years have provided some insight into the water
quality within the lake. There are no state or federal standards for nutrients including the two monitored
within Airlie Gardens (orthophosphate and nitrate/nitrite). That said, the levels of orthophosphate and
nitrate/nitrite observed within the three sites in Airlie Gardens were generally low. However, generally
speaking, since the 2015-2016 program year at the AG-IN site, nitrate/nitrite levels have been relatively
higher on average compared to the other two sites further closer to the outfall and orthophosphate has
been increasing slightly over time across all sites.
Over the past ten (10) years of sampling, the orthophosphate level within AG-IN and AG-FD have averaged
0.07mg/l while the average level of orthophosphate at AG-OUT was 0.08 mg/l. Nitrite/Nitrate levels have
been 0.07 mg/l at AG-IN while AG-FD and AG-OUT averaged 0.04 mg/l and 0.06, respectively. This
suggests that the nutrient-rich stormwater runoff delivered to the lake at AG-IN are ultimately taken up
by aquatic plants and macroalgae within the lake. Phosphorus is a particularly vital nutrient for converting
sunlight into usable energy, and essential to cellular growth and reproduction. Under natural conditions
phosphorus is typically scarce in water. In the late 1960s scientists discovered phosphorus contributed by
human activity to be a major cause of excessive algae growth and degraded lake water quality (MPCA,
2008). The process involving an increase of nutrient loading to a waterbody, called eutrophication, can
lead to algae blooms. As the vegetation dies off and the plant matter decomposes, bacteria take up the
oxygen in the water column, which can be harmful to fish and other aquatic life.
To help combat problems associated with this eutrophication and overall water quality, Airlie Gardens has
implemented initiatives identified in their stormwater master plan. These initiatives include installing
several aerators in the lake to increase the dissolved oxygen levels. In addition, the tributary that delivers
stormwater runoff into the lake just upstream from the AG-IN sampling location was restored in early
2019 which included the planting of native Cypress and the installation of an engineered wetland BMP.
In 2020 the County completed a dredging operation by excavating 5 feet deep by 10 feet wide channels
in the lake, effectively removing approximately 4,000 cubic yards of bottom sediment and material. The
removal of the nutrient-laden sediments should result in decreased levels of orthophosphate and
nitrate/nitrite within the water column which could facilitate a reduction of algal blooms thereby helping
to maintain appropriate levels of dissolved oxygen. Several small algal blooms were confirmed in the pond
at Airlie Gardens this past year. The data has shown that Chlorophyll-a levels had increased at all three
sites during the 2023-2024 sampling period compared to previous years, however, during the 2024-2025
sampling period, these levels have moderated. Despite this moderation, visual observations confirmed
the presence of algal blooms within the lake this past year suggesting that the nutrients that continue to
enter the lake are taken up through plant growth.
APPENDIX A: ADDITIONAL CREEK DATA
Barnards Creek
Sampling was conducted at one site (BC-CBR) within the Barnards Creek watershed (Figure 2).
Dissolved oxygen within BC-CBR ranged between 4.6 mg/l and 10.3 mg/l with a mean value of 6.8 mg/l
(Table 1). No samples contained dissolved oxygen levels below the State standard of 4.0 mg/l for C Sw
waters at the surface (Figure 3).
Chlorophyll-a ranged between 0.0 ug/l and 6.0 ug/l with a mean value of 2.0 ug/l at BC-CBR (Table 1). No
samples surpassed the 40 ug/l standard.
Enterococci ranged between 10 CFU/100 ml and 183 CFU/100 ml with a geometric mean value of 68
CFU/100 ml, which is below the NCDEQ standard of 500 CFU/100 ml for Tier III waters (Table 1). None of
the twelve (12) samples collected during this period exceeded this standard.
Turbidity values were generally good, ranging between 1 and 22 NTU with a mean value of 6 NTU (Table
1). No samples exceeded the State standard of 50 NTU for C SW waters.
Table 2 depicts the ratings for these parameters for the watershed.
Figure 2. Water Quality Sites within the Barnards Creek Watershed
Table 1. Mean values of select parameters from Barnards Creek. Range in parentheses.
Parameter BC-CBR
Turbidity (NTU) 6 (1-22)
Dissolved Oxygen (mg/l) 6.8 (4.6-10.3)
Chlorophyll-a (ug/l) 2 (0-6)
Enterococci (#CFU/100ml) 68 (10-183)
(1) Enterococci values expressed as geometric mean
Figure 3. Dissolved Oxygen at BC-CBR at surface (DO-S) and bottom (DO-B)
Figure 4. Enterococci at BC-CB
Table 2. Ratings of parameters within sampling sites within Barnards Creek
Parameter BC-CBR
Turbidity GOOD
Dissolved Oxygen GOOD
Chlorophyll-a GOOD
Enterococci GOOD
ntero.
Futch Creek
Sampling was conducted at four (4) sites (FC-4, FC-6, FC-13, and FC-FOY) within the Futch Creek watershed
(Figure 5).
Dissolved oxygen within Futch Creek ranged between 4.4mg/l and 10.7 mg/l with a mean value of 7.2
mg/l (Figure 6 – Figure 9, Table 3). Two (2) samples contained dissolved oxygen levels below the State
standard of 5.0 mg/l for SA water.
Chlorophyll-a ranged between 1.0 ug/l and 70.0 ug/l with a mean value of 5.0 ug/l (Table 3). One sample
contained more than the 40ug/l chlorophyll-a standard.
Enterococci ranged between 5 CFU/100ml and 630 CFU/100ml with a geometric mean value of 9
CFU/100ml. One (1) sample collected within Futch Creek exceeded the NCDEQ Enterococci standard of
500 CFU/100 ml for Tier III waters (Figure 10 – Figure 13, Table 3).
Turbidity values were generally low ranging between 1 and 20 NTU with a mean value of 6 NTU (Table 3).
No samples exceeded the State standard of 25 NTU for SA waters during this study period.
Table 4 depicts the ratings for these parameters for the watershed.
Figure 5. Water Quality Sites within the Futch Creek Watershed
Table 3. Mean values of select parameters from Futch Creek. Range in parentheses.
Parameter FC-4 FC-6 FC-13 FC-FOY
Turbidity (NTU) 5 (1-16) 4 (1-9) 8 (2-20) 6 (1-12)
Dissolved
Oxygen (mg/l)
7.2 (5.7-9.2) 7.2 (5.4-9.1) 7.2 (4.4-10.7) 7.0 (5.1-9.8)
Chlorophyll-a
(ug/l)
3(1-6) 3(1-6) 10 (1-70) 4 (1-14)
Enterococci
(#CFU/100ml)
8 (5-48)1 9 (5-630)1 10 (5-118)1 8 (5-121)1
(1)Enterococci values expressed as geometric mean
Figure 6. Dissolved Oxygen at FC-4 at surface (DO-S) and bottom (DO-B)
Figure 7. Dissolved Oxygen at FC-6 at surface (DO-S) and bottom (DO-B)
Figure 8. Dissolved Oxygen at FC-13 at surface (DO-S) and bottom (DO-B)
Figure 9. Dissolved Oxygen at FC-FOY at surface (DO-S) and bottom (DO-B)
Figure 10. Enterococci at FC-4
Figure 11. Enterococci at FC-6
Figure 12. Enterococci at FC-13
Figure 13. Enterococci at FC-FOY
Table 4. Ratings of parameters within sampling sites within Futch Creek
Parameter FC-4 FC-6 FC-13 FC-FOY
Turbidity GOOD GOOD GOOD GOOD
Dissolved Oxygen GOOD GOOD GOOD GOOD
Chlorophyll-a GOOD GOOD GOOD GOOD
Enterococci GOOD GOOD GOOD GOOD
Island Creek
Sampling was conducted at two (2) sites (IC-HS) within the Island Creek watershed (Figure 14).
Dissolved oxygen at Island Creek ranged between 0.5 mg/l and 10.3 mg/l with a mean value of 4.2 mg/l
(Table 5). Ten (10) samples were below the State standard of 4.0 mg/l for C Sw waters during the sampling
period (Figures 15 and 16).
Chlorophyll-a ranged between 0 ug/l and 27 ug/l with a mean value of 5 ug/l (Table 5). No samples
exceeded the State standard of 40 ug/l for chlorophyll-a.
Enterococci ranged between 5 CFU/100ml and 473 CFU/100ml with a geometric mean value of 46
CFU/100ml (Table 5, Figures 17 and 18). No samples collected in Island Creek over this reporting period
contained high levels of Enterococci beyond the NCDEQ standard of 500 CFU/100 ml for Tier III waters.
Turbidity values were generally moderate ranging between 2 and 31 NTU with a mean value of 6 NTU
(Table 5). No samples exceeded the State standard of 50 NTU for C Sw waters in Island Creek during the
reporting period.
Table 6 depicts the ratings for these parameters for the watershed.
Figure 14. Water Quality Site within the Island Creek Watershed
Table 5. Mean values of select parameters from Island Creek. Range in parentheses.
Parameter IC-HS IC-SID
Turbidity (NTU) 6.25 (2-31) 6 (1-18)
Dissolved Oxygen
(mg/l)
4.3 (0.5-9.7) 4.1 (1.0-10.3)
Chlorophyll-a (ug/l) 5 (1-27) 6 (0-26)
Enterococci
(#CFU/100ml)
41 (5-262)1 51 (5-473)1
(1)Enterococci values expressed as geometric mean
Figure 15. Dissolved Oxygen at IC-HS at surface (DO-S) and bottom (DO-B)
Figure 16. Dissolved Oxygen at IC-SID at surface (DO-S) and bottom (DO-B)
Figure 17. Enterococci at IC-HS
Figure 18. Enterococci at IC-SID
Table 6. Ratings of parameters within sampling sites within Island Creek
Parameter IC-HS IC-SID
Turbidity GOOD GOOD
Dissolved Oxygen POOR POOR
Chlorophyll-a GOOD GOOD
Enterococci GOOD GOOD
Lords Creek
Sampling was conducted at one (1) site (LC-RR) within the Lords Creek watershed (Figure 19).
Dissolved oxygen at LC-RR ranged between 4.9 mg/l and 11.2 mg/l with a mean value of 7.4 mg/l (Table
7). No samples were below the State standard of 4.0 mg/l for C Sw waters during the sampling period
(Figure 20).
Chlorophyll-a ranged between 4 ug/l and 22 ug/l with a mean value of 8 ug/l (Table 7). No samples
exceeded the State standard of 40 ug/l for chlorophyll-a.
Enterococci ranged between 5 CFU/100ml and 730 CFU/100ml with a geometric mean value of 29
CFU/100ml (Table 7). One (1) of the twelve (12) samples collected over this reporting period contained
high levels of Enterococci beyond the NCDEQ standard of 500 CFU/100 ml for Tier III waters (Figure 21).
Turbidity values were generally moderate ranging between 3 and 20 NTU with a mean value of 11 NTU
(Table 7). No samples exceeded the State standard of 50 NTU for C Sw waters in Lords Creek during the
reporting period.
Table 8 depicts the ratings for these parameters for the watershed.
Figure 19. Water Quality Site within the Lords Creek Watershed
Table 7. Mean values of select parameters from Lords Creek. Range in parentheses.
Parameter LC-RR
Turbidity (NTU) 11 (3-20)
Dissolved Oxygen (mg/l) 7.4 (4.9-11.2)
Chlorophyll-a (ug/l) 5 (0-27)
Enterococci (#CFU/100ml) 29 (5-730)1
(1)Enterococci values expressed as geometric mean
Figure 20. Dissolved Oxygen at LC-RR at surface (DO-S) and bottom (DO-B)
Figure 21. Enterococci Levels at LC-RR
Table 8. Ratings of parameters within sampling sites within Lords Creek
Parameter LC-RR
Turbidity GOOD
Dissolved Oxygen GOOD
Chlorophyll-a GOOD
Enterococci GOOD
Motts Creek
Sampling was conducted at two (2) sites (MOT-CBR, MOT-ND) within the Motts Creek watershed (Figure
22).
Dissolved oxygen within Motts Creek ranged between 4.3 mg/l and 10.4 mg/l with a mean value of 6.9
mg/l (Table 9). No samples collected during the reporting period contained dissolved oxygen levels below
the standard (Figure 23 and Figure 24).
Chlorophyll-a ranged between 0 ug/l and 22 ug/l with a mean value of 3 ug/l (Table 9). No samples
exceeded the 40ug/l standard.
Enterococci ranged between 10 CFU/100ml and 3,450 CFU/100ml with a geometric mean value of 200
CFU/100 ml (Table 9). Samples exceeded the NCDEQ standard of 500 CFU/100 ml for Tier III waters during
six (6) sampling events during the reporting period (Figure 25 and Figure 26).
Turbidity values were generally good ranging between 3 and 16 NTU with a mean value of 7 NTU (Table
9). No turbidity observations exceeded the State standard of 50 NTU for C Sw waters.
Table 10 depicts the ratings for these parameters for the watershed.
Figure 22. Water Quality Sites within the Motts Creek Watershed
Table 9. Mean values of select parameters from Motts Creek. Range in parentheses.
Parameter MOT-CBR MOT-ND
Turbidity (NTU) 6 (3-12) 9 (4-16)
Dissolved Oxygen (mg/l) 6.5 (4.3-9.3) 7.2 (5.4-10.4)
Chlorophyll-a (ug/l) 4 (0-22) 3 (0-6)
Enterococci (#CFU/100ml) 95 (10-748)1 421 (41-3,450)1
(1)Enterococci values expressed as geometric mean
Figure 23. Dissolved Oxygen at MOT-CBR at surface (DO-S)
Figure 24. Dissolved Oxygen at MOT-ND at surface (DO-S)
Figure 25. Enterococci at MOT-CBR
Figure 26. Enterococci at MOT-ND
Table 10. Ratings of parameters within sampling sites within Motts Creek
Parameter MOT-CBR MOT-ND
Turbidity GOOD GOOD
Dissolved Oxygen GOOD GOOD
Chlorophyll-a GOOD GOOD
Enterococci GOOD POOR
Pages Creek
Sampling was conducted at three (3) sites (PC-BDDS, PC-BDUS, and PC-M) within the Pages Creek
watershed (Figure 27).
Dissolved oxygen within Pages Creek ranged between 3.5 mg/l and 9.9 mg/l with a mean value of 7.2 mg/l
(Figures 28 - 30, Table 11). Over the twelve (12) month study period, the dissolved oxygen levels were
below the State standard three (3) times at PC-BDDS while levels remained above the standard at PC-
BDUS and PC-M.
Chlorophyll-a ranged between 1 ug/l and 57 ug/l with a mean value of 7 ug/l (Table 11). One sample
exceeded the State standard of 40 ug/l for chlorophyll-a.
Enterococci ranged between 5 CFU/100 ml and 24,196 CFU/100 ml with a geometric mean value of 64
CFU/100 ml (Figures 31 – 33, Table 11). Five (5) samples from PC-BDDS and four (4) samples from PC-
BDUS contained levels higher than the NCDEQ standard. Enterococci was within the standard at PC-M
during all twelve (12) sampling events.
Turbidity values were generally good ranging between 0 and 31 NTU with a mean value of 8 NTU (Table
11). One (1) of the observed turbidity values exceeded the State standard of 25 NTU for class SA waters.
Table 12 depicts the ratings for these parameters for the watershed.
Figure 27. Water Quality Sites within the Pages Creek Watershed
Figure 28. Water Quality Sites within the Pages Creek Watershed
Table 11. Mean values of select parameters from Pages Creek. Range in parentheses.
Parameter PC-BDDS PC-BDUS PC-M
Turbidity (NTU) 10 (3-23) 12 (3-31) 4 (0-19)
Dissolved Oxygen (mg/l) 6.1 (3.5-9.7) 7.9 (5.3-9.9) 7.5 (6.3-9.3)
Chlorophyll-a (ug/l) 13 (1-57) 6 (1-23) 3 (1-7)
Enterococci (#CFU/100ml) 262 (10-3,080)1 122 (5-24,196)1 8 (5-63)1
(1)Enterococci values expressed as geometric mean
Figure 29 Dissolved Oxygen at PC-BDDS at surface (DO-S)
Figure 30. Dissolved Oxygen at PC-BDUS at surface (DO-S)
Figure 31. Dissolved Oxygen at PC-M at surface (DO-S) and bottom (DO-B)
Figure 32. Enterococci at PC-BDDS
Figure 33. Enterococci at PC-BDUS
Figure 34. Enterococci at PC-M
Table 12. Ratings of parameters within sampling sites within Pages Creek
Parameter PC-BDDS PC-BDUS PC-M
Turbidity GOOD GOOD GOOD
Dissolved Oxygen FAIR GOOD GOOD
Chlorophyll-a GOOD GOOD GOOD
Enterococci POOR POOR GOOD
Prince George
Sampling was conducted at three (3) sites (PG-CH, PG-ML, and PG-NC) within the Prince George Creek
watershed (Figure 34).
Dissolved oxygen within Prince George Creek ranged between 0.6 mg/l and 10.3 mg/l with a mean value
of 4.0 mg/l (Table 13). Surface dissolved oxygen values were below the State standard of 4.0 mg/l for C
Sw on fourteen (14) occasions during the reporting period at PG-NC and PG-ML and four (4) times at PG-
CH (Figures 35 – 37, Table 13).
Chlorophyll-a ranged between 1 ug/l and 43 ug/l with a mean value of 6 ug/l (Table 13). One sample from
Prince George Creek exceeded the 40 ug/l standard.
Enterococci ranged between 5 CFU/100ml and 4,880 CFU/100ml with a geometric mean value of 112
CFU/100ml (Table 13). Three (3) samples collected from within Prince George Creek contained
Enterococci levels above the NCDEQ standard of 500 CFU/100ml for Tier III waters (Figures 38 – 40).
Turbidity values were generally good ranging between 1 and 27 NTU with a mean value of 6 NTU (Table
13). No samples exceeded the State standard of 50 NTU for C Sw waters.
Table 14 depicts the ratings for these parameters for the watershed.
Figure 35. Water Quality Sites within the Prince George Creek Watershed
Table 13. Mean values of select parameters from Prince George Creek. Range in parentheses.
Parameter PG-CH PG-ML PG-NC
Turbidity (NTU) 6 (1-27) 4 (1-16) 8 (1-22)
Dissolved Oxygen (mg/l) 4.6 (2.3-8.7) 5.0 (0.9-10.3) 2.5 (0.6-5.4)
Chlorophyll-a (ug/l) 5 (1-16) 5 (1-25) 7 (1-43)
Enterococci (#CFU/100ml) 181 (41-3,650)1 135 (31-1,990)1 57 (5-4,880)1
(1)Enterococci values expressed as geometric mean
Figure 36. Dissolved Oxygen at PG-CH at surface (DO-S) and bottom (DO-B)
Figure 37. Dissolved Oxygen at PG-ML at surface (DO-S)
Figure 38. Dissolved Oxygen at PG-NC at surface (DO-S) and bottom (DO-B)
Figure 39. Enterococci at PG-CH
Figure 40. Enterococci at PG-ML
Figure 41. Enterococci at PG-NC
Table 14. Ratings of parameters within sampling sites within Prince George Creek
Parameter PG-CH PG-ML PG-NC
Turbidity GOOD GOOD GOOD
Dissolved Oxygen POOR POOR POOR
Chlorophyll-a GOOD GOOD GOOD
Enterococci GOOD GOOD GOOD
Smith Creek
Sampling was conducted at four (4) sites (SC-CH, SC-NK, SC-GR, SC-CD) within the Smith Creek watershed
(Figure 41).
Dissolved oxygen within the creek ranged between 1.9 mg/l and 11.8 mg/l with a mean value of 7.3 mg/l
(Table 15; Figures 42 – 45). Three (3) samples collected were below the State standard.
Chlorophyll-a ranged between 0 ug/l and 45 ug/l with a mean value of 8 ug/l (Table 15). One (1) sample
exceeded the State Standard for chlorophyll-a from within Smith Creek.
Enterococci ranged between 5 CFU/100 ml and 3,260 CFU/100 ml with a geometric mean value of 85
CFU/100ml (Table 15). Six (6) samples exceeded the NCDEQ standard of 500 CFU/100 ml for Tier III waters
(Figure 46-49).
Turbidity values were generally good ranging between 2 and 30 NTU with a mean value of 9 NTU (Table
15). No observations exceeded the State standard of 50 NTU for SW class C waters.
Table 16 depicts the ratings for these parameters for the watershed.
Figure 42 Water Quality Sites within the Smith Creek Watershed
Table 15. Mean values of select parameters from Smith Creek. Range in parentheses.
Parameter SC-CH SC-CD SC-GR SC-NK
Turbidity (NTU) 10 (4-17) 10 (2-30) 9 (2-21) 8 (3-26)
Dissolved Oxygen (mg/l) 6.2 (1.9-10.9) 8.2 (6.8-11.8) 8.0 (6.4-10.6) 6.7 (3.8-10.2)
Chlorophyll-a (ug/l) 5 (0-26) 10 (1-45) 5 (1-22) 11 (2-26)
Enterococci (#CFU/100ml) 51 (5-160) 212 (10-2,280)1 103 (10-3,260)1 67 (5-2,700)1
(1)Enterococci values expressed as geometric mean
Figure 43. Dissolved Oxygen at SC-CH at surface (DO-S)
Figure 44. Dissolved Oxygen at SC-CD at surface (DO-S)
Figure 44. Dissolved Oxygen at SC-GR at surface (DO-S)
Figure 45. Dissolved Oxygen at SC-NK at surface (DO-S) and bottom (DO-B)
Figure 46. Enterococci at SC-CH
Figure 47. Enterococci at SC-CD
Figure 48. Enterococci at SC-GR
Figure 49. Enterococci at SC-NK
Table 16. Ratings of parameters within sampling sites within Smith Creek
Parameter SC-CH SC-CD SC-GR SC-NK
Turbidity GOOD GOOD GOOD GOOD
Dissolved Oxygen FAIR GOOD GOOD GOOD
Chlorophyll-a GOOD GOOD GOOD GOOD
Enterococci GOOD FAIR GOOD GOOD
Airlie Gardens
Airlie Gardens is a 67-acre public garden owned and operated by New Hanover County since 1999. The
property, located within the Bradley Creek watershed, and includes a 10-acre freshwater lake. The lake
receives input from several stormwater culverts which serve to manage stormwater in the area. Water
quality monitoring was conducted at three locations within the lake: AG-IN, located on the northern
portion of the lake where stormwater enters the lake; AG-FD, located in a central portion of the lake; and
AG-OUT, located at the southern portion of the lake in proximity to the drainage outfall (Figure 50, Table
17).
Dissolved oxygen within the lake ranged between 1.9 mg/l and 12.2 mg/l with a mean value of 6.1 mg/l
(Table 17; Figures 51-53). Nine (9) samples were below the State standard for dissolved oxygen, eight (8)
of which were observed within AG-IN.
Turbidity values were generally good ranging between 1 and 37 NTU with a mean value of 7.9 NTU (Table
17). No samples exceeded the State standard of 50 NTU for Class C waters.
Chlorophyll-a ranged from 3 mg/l to 123 mg/l with a mean value of 37 mg/l. The standard of 40 mg/l was
exceeded twelve (12) times.
Figure 50. Airlie Gardens Sampling Sites
Figure 51. Dissolved Oxygen at AG-IN
Figure 52. Dissolved Oxygen at AG-FD
Figure 53. Dissolved Oxygen at AG-OUT
Table 17. Mean values of select parameters from Airlie Gardens. Range provided in parentheses.
Parameter AG-IN AG-FD AG-OUT
Turbidity (NTU) 4 (1-12) 8 (3-23) 11 (3-37)
Dissolved
Oxygen (mg/l)
4.5 (1.9-10.8) 7.5 (5.0-12.2) 6.2 (3.7-8.8)
Chlorophyll-a
(mg/l)
26 (3-98) 42 (5-123) 44 (4-106)
Orthophosphate 0.05 (0.01-0.20) 0.09 (0.01-0.35) 0.13 (0.01-0.45)
Nitrate/Nitrite 0.09 (0.01-0.20) 0.09 (0.01-0.35) 0.22 (0.01-0.91)
Long Term Trends within Airlie Gardens
Monitoring within three sites in the lake at Airlie Gardens began in the summer of 2015. Since that time,
samples have been collected monthly for the analysis of orthophosphate and nitrate/nitrite (two types of
nutrients). In the summer of 2016, monthly samples were collected for the analysis of Chlorophyll-a as
well. Over the course of time, some trends have emerged. On average, Chlorophyll-a levels at AG-FD and
AG-OUT have been considerably higher than the levels observed at AG-IN over time. This may indicate
that the nutrients entering the lake from stormwater runoff collected near AG-IN may be taken up by
growing vegetation (algae and other aquatic plant matter) as the water flows towards the outfall in
proximity to AG-OUT.
Figure 54. Chlorophyll-a levels at Airlie Gardens Over Time
When examining the levels of nutrients over time within these sampling sites, on average, higher levels
of nitrite/nitrate have been observed at AG-IN compared to the other two sampling sites on an annual
basis since sampling began in 2015 (Figure 55). Over the past ten (10) years, nitrite/nitrate levels have
averaged 0.07 mg/l, 0.04 mg/l, and 0.06 mg/l at AG-IN, AG-FD, and AG-OUT, respectively. It should be
noted, however, that this trend was not observed during the 2024/2025 sampling period as the average
nitrite/nitrate level at AG-OUT (0.22 mg/l) was more than double the value observed at both AG-IN and
AG-FD (both 0.09 mg/l).
0
10
20
30
0
50
0
0
0
0
AG IN AG F AG OUT
Ch
l
o
r
o
p
h
y
l
l
a
(mg
l)
Chlorophyll a evels in Airlie Gardens Over Time
201 201 201 201 201 201
201 2020 2020 2021 2021 2022
2022 2023 2023 202 202 2025
This trend of diminishing nutrient levels across the lake (from the stormwater input to the outfall area)
held true for orthophosphate as well for the first three sampling periods, however the values were then
similar across the lake over the next three years followed by a period of four years where there was more
orthophosphate at the outfall compared to the intake area (Figure 56). Collectively, over the past ten (10)
years of sampling, the average orthophosphate levels have been 0.07 mg/l at AG-IN and AG-FD and 0.08
mg/l at AG-OUT. This data suggests that Nitrogen may be the limiting nutrient regulating vegetative
growth within the lake.
Overall, there had been a trend of increasing levels of both nutrients within the lake over recent years.
During the 2015-2016 study period, nitrate/nitrite levels averaged 0.03 mg/l and orthophosphate
averaged 0.02 mg/l. While the levels have oscillated over time to some extent, the overall trend of
increased nutrients has culminated with average nitrate/nitrite and orthophosphate levels of 0.13 mg/l
and 0.09, respectively during the 2024-2025 study period (Figure 57). The increase in levels of Chlorophyll-
a over the past year, as previously discussed, may be a result of taking up some of these available nutrients
and converting them to plant matter.
Figure 55. Nitrate/Nitrate Levels in Airlie Gardens Over Time
0.00
0.05
0.10
0.15
0.20
0.25
AG IN AG F AG OUT
NO
x
(mg
l)
Nitrate Nitrite evels in Airlie Gardens Over Time
2015 201 201 201 201 201 201 201
201 2020 2020 2021 2021 2022 2022 2023
2023 202 202 2025
Figure 56. Orthophosphate Levels in Airlie Gardens Over Time
Figure 57. Average Nitrite/Nitrate and Orthophosphate Levels in Airlie Gardens
Dissolved oxygen within the lake has been good on average, through the years within each site, however,
the oxygen levels at AG-FD and AG-OUT have been consistently higher in comparison to the levels
observed at AG-IN (Figure 58). At each site, the dissolved oxygen levels generally increased during the
warmer summer months and increased during the colder winter months.
0.03
0.02
0.0
0.12
0.1
0.22
AG IN AG F AG OUT
Or
t
h
o
p
h
o
s
p
h
a
t
e
(mg
l)
Orthophosphate evels in Airlie Gardens Over Time
2015 201 201 201 201 201 201 201
201 2020 2020 2021 2021 2022 2022 2023
2023 202 202 2025
0.00
0.02
0.0
0.0
0.0
0.10
0.12
0.1
0.1
0.1
mg
l
Average Nitrite Nitrate and Orthophosphate evels
in Airlie Gardens
Nitrite Nitrate Orthophosphate
Figure 58. Dissolved Oxygen in Airlie Gardens Over Time
0.0
2.0
.0
.0
.0
10.0
AG IN AG F AG OUT
i
s
s
o
l
v
e
d
O
x
y
g
e
n
(mg
l)
issolved Oxygen evels in Airlie Gardens Over
Time
2015 201 201 201 201 201 201 201
201 2020 2020 2021 2021 2022 2022 2023
2023 202 202 2025
APPENDIX B: LONG TERM TRENDS
In order to assess the long-term trends in water quality, a database has been created to include the data
collected within the eight tidal creeks sampled. Since this is the first-year reporting on parameters of
Island Creek, long-term trends have yet to be identified so for the purpose of this section, Island Creek
has been omitted. The long-term trends from the seven legacy creeks have been derived from data
obtained between July 2008 and June 2024.
Dissolved Oxygen
Figure 59 depicts the long-term trends in dissolved oxygen within the seven creeks examined within this
study. The data show 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. Since 2008,
dissolved oxygen levels were below the State standard within surface samples 50%, 39%, 21%, and 15%
of the time within Island Creek, Prince George Creek, Pages Creek, and Futch Creek, respectively.
Dissolved oxygen was below the standard 9% of the time from within Motts Creek while Barnards Creek,
Smith Creek, and Lords Creek exceeded the standard 8%, 6% and 4% of the time, respectively. The
majority of the samples that fell below the standard for dissolved oxygen since 2008, were observed
during June, July, and August when water temperatures were the highest. It should be noted that low
dissolved oxygen is a negative indicator of water quality, while high dissolved oxygen is positive for overall
water quality.
Figure 59. Long-term surface dissolved oxygen data within tidal creeks. Note: The dissolved oxygen standard
within Pages Creek and Futch Creek is 5.0 mg/l while the standard for the other creeks is 4.0 mg/l.
0
1
2
3
5
Pages Futch mith arnards ords Mo Prince
George
Island
200 200 2010 2011 2012 2013
201 2015 201 201 201 201
2020 2021 2022 2023 202
Turbidity
Figure 60 depicts the long-term trends in turbidity within the seven (7) creeks examined within this study
over the long-term period beginning in 2008 and Island Creek which was added to the program in 2021.
In general, the long-term trend of turbidity has remained fairly constant within each creek on an annual
basis, however several creeks have experienced minor increases over time and seasonal patterns have
emerged. This includes higher turbidity observations during the warmer months and lower turbidity
during the cooler months. Since 2008, the turbidity standard from observations monitored from the
surface waters was only breached twenty-three (23) times in total: nine (9) from within Pages Creek, eight
(8)) from within Smith Creek, two (2) from within Prince George Creek, and one time each from within
Barnards Creek, Lords Creek and Motts Creek.
Figure 60. Long-term surface turbidity data within tidal creeks. Note: The turbidity standard within Pages Creek
and Futch Creek is 25 NTUs while the standard for the other creeks is 50 NTUs.
0
5
10
15
20
Pages Futch mith arnards ords Mo Prince
George
Island
Tu
r
b
i
d
i
t
y
(NT
U
)
Turbidity (NTU) evels in Tidal Creeks Over Time
200 200 2010 2011 2012 2013 201 2015 201
201 201 201 2020 2021 2022 2023 202
Chlorophyll-a
Figure 61 depicts the long-term trends in chlorophyll-a within the seven creeks examined within this
study. In general, the long-term trend of chlorophyll-a has remained fairly constant within each creek.
Contrary 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 in July 2008, only 53
exceedances of the chlorophyll-a standard were observed of the 3,924 samples collected.
Figure 61. Long-term chlorophyll-a data within tidal creeks. There is no standard for chlorophyll-a.
0
12
1
Pages Futch mith arnards ords Mo Prince
George
Island
Creek
Ch
l
a
(ug
l)
Chl evels in Tidal Creeks Over Time
200 200 2010 2011 2012 2013 201 2015 201
201 201 201 2020 2021 2022 2023 202
Enterococci
Figure 62 and Table 18 depict the long-term trends in Enterococci within the eight (8) creeks examined
within this long-term study. Of these creeks, Motts Creek, Pages Creek, Smith Creek, and Prince George
Creek have maintained relatively higher levels of bacteria over time compared to Lords Creek, Futch
Creek, and Island Creek. The levels of bacteria in Barnards, Smith, and Motts Creek have moderated over
recent years (Table 18). Two sites in particular within the Bayshore community (PC-BDDS and PC-BDUS)
in the Pages Creek watershed have demonstrated relatively high levels of Enterococci bacteria over time
exceeding the standard 45% and 53% of the time, respectively. However, over the past 3 sampling periods,
the percentage of exceedances at PC-BDUS has decreased to 19%.
Since June 2008, samples collected within Motts Creek, Pages Creek, and Smith Creek exceeded the State
standard for Enterococci 36%, 35%, and 22% of the time, respectively. Prince George Creek exceeded the
standard 20% of the time while Barnards Creek exceeded the standard 19% of the time. Lords Creek
exceeded the standard 8% of the time while Futch Creek and Island Creek only exceeded the standard for
Enterococci 3% and 2% of the time, respectively.
Figure 62. Long-term Enterococci data within tidal creeks. See Appendix D for Enterococci standards.
0
200
00
00
00
1000
1200
Pages Futch mith arnards ords Mo Prince
Georges
Island
n
t
e
r
o
c
o
c
c
i
(CF
U
10
0
ml
)
evels in Tidal Creeks Over Time
200 200 2010 2011 2012 2013 201 2015 201
201 201 201 2020 2021 2022 2023 202
Table 18. Enterococci ratings for each watershed during all reporting periods.
Study
Period
Barnards
Creek
Futch
Creek
Lords
Creek
Motts
Creek
Pages
Creek
Prince
George
Creek
Smith
Creek
Island
Creek*
2008-2009 POOR GOOD FAIR POOR POOR FAIR POOR
2009-2010 POOR GOOD POOR POOR POOR POOR POOR
2010-2011 POOR GOOD GOOD POOR FAIR POOR POOR
2011-2012 POOR GOOD GOOD POOR POOR POOR POOR
2012-2013 POOR GOOD FAIR POOR POOR POOR POOR
2013-2014 GOOD GOOD GOOD POOR POOR POOR FAIR
2014-2015 GOOD GOOD GOOD POOR POOR POOR FAIR
2015-2016 POOR FAIR FAIR POOR POOR POOR FAIR
2016-2017 GOOD GOOD GOOD FAIR POOR GOOD FAIR
2017-2018 FAIR FAIR POOR FAIR POOR POOR POOR
2018-2019 FAIR GOOD FAIR FAIR FAIR GOOD GOOD
2019-2020 GOOD GOOD GOOD FAIR FAIR GOOD GOOD
2020-2021 GOOD GOOD GOOD FAIR POOR FAIR GOOD
2021-2022 GOOD GOOD GOOD GOOD POOR FAIR GOOD GOOD
2022-2023 GOOD GOOD GOOD FAIR FAIR GOOD GOOD GOOD
2023-2024 GOOD GOOD GOOD POOR FAIR FAIR FAIR GOOD
2024-2025 GOOD GOOD GOOD FAIR FAIR GOOD FAIR GOOD
* Monitoring at Island Creek began in program year 2021-2022
APPENDIX C
Water Quality Management
Water quality remains a longstanding priority in New Hanover County, recognized at both the state and
local levels as essential to environmental health, public safety, and community resilience. The County has
a rich history of research, monitoring, and education that continues through the work of multiple
departments and partner agencies. While the New Hanover County Water Quality Monitoring Program
focuses on tracking trends in key water quality parameters, other departments—including Health and
Human Services, Engineering, Soil and Water Conservation, and Sustainability—contribute to efforts that
collectively enhance watershed health. Countywide initiatives include property acquisition for
conservation, installation of stormwater best management practices such as rain gardens and infiltration
basins, microbial source tracking, public outreach and education, watershed planning, and drainage
improvement projects. These efforts are strengthened through ongoing collaboration with the Cape Fear
Public Utility Authority (CFPUA), the University of North Carolina Wilmington (UNCW), the North Carolina
Department of Environmental Quality (NCDEQ), and the City of Wilmington, reflecting a shared
commitment to protecting and improving local water resources.
Over the past decade, New Hanover County’s monitoring of water quality indicates that while there has
been general improvements in overall water quality, over the life of the program, water quality
parameters have either remained steady or have slightly improved. While urbanization and development
can be factors impacting water quality, the level of the development occurring is not impacting water
quality by the same amount, meaning the effects from development is being minimized. This suggests
that there are other factors interacting with the various parameters that are measured by this program
to offset potential negative impacts to overall water quality.
Improvement Efforts in Pages Creek
Of all of the parameters that are monitored and analyzed, enterococci bacteria is one that poses the most
threat to human and environmental health. While elevated levels have been seen at multiple creeks over
the years, most of the efforts to identify the source of bacteria have been at Pages Creek because of the
number of samples that have exceeded the state standard. Two sites in particular within the Bayshore
community (PC-BDDS and PC-BDUS) have exceeded the standard 43% and 58% of the time since testing
began in 2007. In addition, Pages Creek is designated as a Class SA Water, meaning it is an area prime for
shellfishing. However, Pages Creek is currently “closed” to shellfishing due to the elevated levels of
enterococci bacteria.
Since 2008 there have been multiple efforts to research, test and target the source of bacteria seen in
Pages Creek.
1993 Tidal Creek Sampling and Sewer Expansion –
The County launched water testing with UNCW, and expanded sewer
lines
Land Preserved – Peterson Tract acquired by the County to protect
Pages Creek headwaters (now Pages Creek Park Preserve)
Septic & Sewer Work in Bayshore – The County inspected lift
stations, removed abandoned septic tanks
Water Quality Monitoring & Source Tracking – Updated process
and conducted first source study in Pages Creek
Bacteria Report – Study on upper Pages Creek explored potential
sources of bacterial pollution
No Discharge Zone (NDZ) Established – Federal government
designated the County as NDZ in response to county resolution
Force Main Replaced – Replaced and re-routed force main
around Marsh Oaks Dr. to the Porters Neck area and Blue Point
pump station
Source Tracking Study – Expanded study in collaboration with
UNC-Chapel Hill was performed in Pages Creek, taking 6 samples
at each site following heavy rains
Whole-Basin CCTV Work – CFPUA began whole-basin camera
inspection (CCTV) and vactor cleaning in Pages Creek area
Thermal Imaging Study –Conducted with UNCW, using heat-
sensing tools to find possible pollution leaks into Pages Creek
Testing Near Infrastructure –Focused on “seeps” near sewer
pipes to find if leaking infrastructure was polluting the creek
CFPUA Replacements – Country Haven pump station and force
main were replaced
Full-Creek Sampling – Expanded sampling to 20 locations in Pages
Creek
CFPUA Force Main Repairs – Associated with failures at Bayshore
1 Pump Station
Pages Creek Watershed Restoration Plan Begins –Developed in
partnership with New Hanover County Soil & Water Conservation
District and approved by NC Division of Water Quality
2002
2002
2008
2009
2010
2013
2013
2015
2015
2021
2022
2023
2024
2024
New Hanover County continues to monitor water quality and keep an open line of communication with
the Cape Fear Public Utility Authority and the residents in the area to “keep an eye” out for any emerging
issues. New Hanover County remains committed to protecting and improving water quality in the Pages
Creek watershed through continued collaboration, research, and community engagement. Building on
recent progress, the County and its partners are advancing several grant-funded projects and studies,
including the installation of new stormwater control measures, feasibility assessments for restoration on
FEMA buy-out properties, and hydrologic evaluations in Queen’s Point and Anchors end. Additional
sampling will help distinguish between human and non-human sources of contamination, guiding future
management strategies. The County will also maintain monitoring of identified hotspots, coordinate with
CFPUA to evaluate nearby septic and sewer systems, and continue implementing the Pages Creek
Watershed Restoration Plan initiated in 2024. Ongoing outreach and education will ensure residents
remain informed and engaged as these efforts move forward, supporting the long-term health and
resilience of the watershed.
Improvement Efforts within Airlie Gardens
At Airlie Gardens to help combat problems associated with eutrophication and overall water quality within
the lake, the Park and Gardens department has implemented initiatives identified in their stormwater
master plan. In 2018, a series of significant water quality and restoration projects were completed at
Airlie Gardens to enhance stormwater management and improve the ecological function of the site. These
efforts included enlarging and deepening the existing forebay to increase its capacity for capturing runoff
and allowing sediment to settle, as well as restoring the stream segment between the forebay and Airlie
Lake to promote additional sediment filtration. Channels and deep pockets on both sides of Airlie Lake
were dredged to improve water circulation, and a cypress swamp was established in the area where runoff
flows from Airlie Road to help slow and filter stormwater. Additional improvements included regrading
and replanting along the nature trail to increase water absorption and coordinating with the developer of
Airlie at Wrightsville Sound to direct all stormwater runoff into the forebay system.
Routine dredging continues to be an important part of maintaining the lake’s water quality and storage
capacity. Airlie Lake was last dredged in 2020, with plans to reassess conditions within the next few years
and maintain a ten-year dredging cycle. The forebay was most recently dredged in January 2025 and will
continue on a four- to five-year maintenance schedule. In addition, the Airlie Foundation has included a
bathymetric survey in its Capital Improvement Plan (CIP) for Fiscal Year 2028, which will help guide future
maintenance and sediment management strategies.
APPENDIX D
Water Classifications
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:
C: Waters: Protected for uses such as secondary recreation, fishing, wildlife, fish consumption, aquatic
life including propagation, survival and maintenance of biological integrity, and agriculture. Secondary
recreation includes wading, boating, and other uses involving human body contact with water where such
activities take place in an infrequent, unorganized, or incidental manner. This includes the lake within
Airlie Gardens.
C Sw: Freshwater that is protected for aquatic life and secondary recreation uses. The “ w” 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 George 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.
Parameter Definitions
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.
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 a water body turning
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 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.
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.
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.
Orthophosphate
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.
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.
Standards
Water quality standards have been established legislatively for a number of these parameters (Table 19).
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 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/100 ml, 158 CFU/100 ml, 276 CFU/100 ml, and 501 CFU/100 ml 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 4). 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 four days a month during the swimming season. Single sample standards for Tiers I, II,
and III are 104 CFU/100 ml, 276 CFU/100 ml, and 500 CFU/100 ml, respectively (Table 21). A geometric
mean of 35 CFU/100 ml within Tier I swimming areas may also be utilized if at least five samples are
collected within 30 days. The creeks and the lake in Airlie Gardens 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 (Tier Classifications
Table 22). Based on this analysis, of the twenty (20) tidal creek sampling sites, two (2) could be considered
Tier II and eighteen (18) could be considered Tier III. All three (3) of the Airlie Garden sites are considered
Tier III.
Parameter Standards
Table 19. North Carolina Water Quality Standards
Parameter Standard for C Waters Standard for C Sw Waters Standard for SA Waters
Dissolved Oxygen 4.0 mg/la 4.0 mg/la 5.0 mg/l
Turbidity 50 NTU 50 NTU 25 NTU
pH 6.0-9.0b 6.0-9.0b 6.8-8.5
Chlorophyll-a 40.0 ug/l 40.0 ug/l 40.0 ug/l
Fecal Coliform
Geometric Mean (5
samples within 30
days) <200 CFU/100ml;
or single sample <400
CFU/100ml
Geometric Mean (5
samples within 30 days)
<200 CFU/100ml; or single
sample <400 CFU/100ml
Geometric Mean (5
samples within 30 days)
<14 CFU/100ml; or 10%
of samples <43
CFU/100ml
Enterococci c
Geometric Mean (5
samples within 30
days) <35 CFU/100ml
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 DEQ Recreational Water
Quality Program
Table 20. Single sample standards for Enterococci as determined by the US EPA
Description Single sample maximum
Designated beach areas < 104 CFU/100 ml
Swimming areas with moderate full body contact < 158 CFU/100 ml
Lightly used full body contact swimming areas < 276 CFU/100 ml
Infrequently used full body contact swimming areas < 501 CFU/100 ml
Table 21. Single sample standards for Enterococci as determined by the NC DEQ Recreational Water Quality Program
Description Single sample maximum
Tier I, swimming areas used daily during the swimming season <104 CFU/100 ml
Tier II, swimming areas used three days a week during the swimming
season <276 CFU/100 ml
Tier III, swimming areas used on average four days a month during the
swimming season <500 CFU/100 ml
Tier Classifications
Table 22. Tier Classification for New Hanover County Water Quality Monitoring Sites
Site
Name
Proposed Tier
Classification Boating or Swimming Access Comments
AG-FD Tier III No Central portion of Airlie Gardens Lake
AG-IN Tier III No Northern portion of Airlie Gardens Lake
AG-OUT Tier III No Southern portion of Airlie Gardens Lake
BC-CBR Tier III No Adjacent to culvert off Carolina Beach Road
FC-13 Tier III No Private docks are the only means of direct access
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-FOY Tier III No No clear access points (no docks on Foy branch)
IC-HS Tier III No Adjacent to culvert off Holly Shelter Road
IC-SID Tier III No Adjacent to culvert off Sidbury Road
LC-RR Tier III No Adjacent to bridge on River Road
MOT-CBR Tier III No Adjacent to culvert off Carolina Beach Road
MOT-ND Tier III No Adjacent to small bridge on Normandy Drive
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
PC-M Tier II Yes Direct access via Canady's Yacht Basin Marina
PG-CH Tier III No Adjacent to culvert on Castle Hayne Road
PG-ML Tier III No Small boat launch site on private property
PG-NC Tier III No Adjacent to culvert on North College Road
SC-CD Tier III No Narrow, shallow. Adjacent to Candlewood Drive
SC-CH Tier III No Adjacent to bridge on Castle Hayne Road
SC-GR Tier III No Adjacent to culvert on Gordon Road
SC-NK Tier III No Adjacent to bridge on North Kerr
Sampling Sites & Locations
Table 23. List of Tidal Creek Sampling Sites
Creek Name Site Name Site Code Latitude Longitude
Barnards Creek Carolina Beach Road BC-CBR 34° 09.522 77° 54.712
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
Island Creek Holly Shelter IC-HS 34° 22.172 77° 48.544
Island Creek Sidbury Road IC-SID 34° 20.188 77° 49.032
Lords Creek River Road LC-RR 34° 05.185 77° 55.275
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
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
Prince George Creek Marathon Landing PG-ML 34° 21.088 77° 55.349
Prince George Creek Castle Hayne Road PG-CH 34° 20.675 77° 54.217
Prince George Creek North College PG-NC 34° 20.331 77° 53.607
Smith Creek Castle Hayne Road SC-CH 34° 15.541 77° 56.325
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
Table 24. List of Airlie Gardens Sampling Sites
Site Name Site Code Latitude Longitude
Airlie Gardens In AG-IN 34° 21749 77° 82873
Airlie Gardens Floating Dock AG-FD 34° 21549 77° 82796
Airlie Gardens Out AG-OUT 34° 21336 77° 82713
Methods
These seven (7) tidal creeks included within this study and the lake in Airlie Gardens are primarily located
in the unincorporated portion of New Hanover County. Sampling sites were accessed from land, generally
near a bridge or culvert crossing, or by boat. Each tidal creek 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/). The sites sampled within Airlie
Gardens are not influenced by the tide and therefore no efforts were made to associate the timing of
sampling with the tidal stage in the surrounding waters.
Due to time constraints, monthly sampling events were conducted on three subsequent days each month.
Sites within Airlie Gardens, Lords Creek, Motts Creek, and Barnards Creek were visited on the first
sampling day while Smith Creek and Prince George 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 = 0.1 m) and near the creek bottom at sites with depths greater than 0.5 m. 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 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
• Enterococci: EnterolertE
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