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HomeMy WebLinkAboutNHC_Water Quality Report_2023-2024 V3NEW HANOVER COUNTY WATER QUALITY MONITORING PROGRAM 2023-2024 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., 2024. New Hanover County Water Quality Monitoring Program: 2023-2024 Final Report. New Hanover County, North Carolina: Coastal Protection Engineering of North Carolina, Inc. December 2024 EXECUTIVE SUMMARY This report represents the findings of the New Hanover County Water Quality Monitoring Program for the period July 2023 through June 2024. 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 2023-2024 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 at each creek to determine the impact (if any) of the built environment on 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 11%-25% of the times sampled, or a “Poor” rating for greater than 25% of the sampling times. Ratings by watershed during the 2022-2023 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 FAIR POOR GOOD FAIR FAIR POOR GOOD  Chlorophyll-a GOOD GOOD GOOD GOOD GOOD GOOD GOOD GOOD  Enterococci GOOD GOOD GOOD GOOD POOR FAIR FAIR FAIR  Long Term Trends 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, turbidity and chlorophyll-a levels over time have not been relatively low within the sampled creeks. Likewise, dissolved oxygen levels have not changed drastically from year to year which the exception at Futch Creek which saw overall levels go from “Good” in 2022-2023 to “Fair” for this program year. The long-term data shows that the dissolved oxygen levels at Futch Creek has varied between “Good” and “Fair” since 2008. The trend of low dissolved oxygen levels remained during this sampling period at Prince George Creek where levels have been consistently low over time. This is likely due to the creek’s naturally slow water flow, which is more characteristic of swamp-like waters. Slower moving waters typically contain lower dissolved oxygen levels. Barnards Creek, Lords Creek, and Smith Creek continued to contain good levels of dissolved oxygen this year as has been observed in the past. Enterococci bacteria levels during the 2023-2024 sampling period remained the same as the previous sampling period for Barnards Creek, Futch Creek, Lords Creek, and Pages Creek while Motts Creek changed from “Fair” to “Poor” and Prince George Creek and Smith Creek changed from “Good” to “Fair” 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. Monitoring at Island Creek began in 2021 with one monitoring site off Sidbury Road with a second site added in 2022 off Holly Shelter Road. Since then a trend of low dissolved oxygen levels have emerged. In addition there have been some elevated levels of enterococci bacteria. Since this is relatively rural area with little surrounding development, bacteria in this case could be from wildlife sources in the surrounding forests. One subdivision off Sidbury Road consisting of about 40 homes relies on septic as well as subdivision in Pender County off Holly Shelter. The proximity of these septic systems to the creek could be contributing to the elevated levels. In addition to monitoring the tidal creeks, in 2015 New Hanover County began monthly monitoring at the lake at Airlie Gardens 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 varies significantly over an annual basis, increasing during the warmer summer months and decreasing during the colder winter months. Overall, there are no current concerns with the dissolved oxygen levels within the lake. Over the past nine years, 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 four years this trend has reversed, where orthophosphate was lower at the intake and higher at the outfall of the lake. 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, there had been an incremental trend of increasing amounts of orthophosphate each year until this past sampling period when these levels declined. A similar trend has been observed for Nitrite/Nitrate since 2019 where levels have been declining. In recent years chlorophyll-a levels have increased throughout the lake with a noticeably higher rate of increase at the middle and in proximity to the outfall of the lake 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. In general, chlorophyll-a levels have steadily increased within the lake over time since chlorophyll-a sampling began in 2016. Key Takeaways With few exceptions, Futch Creek, Island Creek, and Lords Creek have generally contained low levels of enterococcus over the entire course of the program. Several creeks have improved water quality in terms of enterococcus bacteria over the years: 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. At Motts Creek, 53% of samples exceeded the standard between 2008 to 2015. Since 2015, the percentage of sample exceeding the standard dropped to 19%. 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 At Smith Creek, 31% of samples collected between 2008 to 2018 exceeded the standard. Between 2019 to Present, only 7% of samples exceeded the standard. Pages Creek has continued to demonstrate elevated levels of enterococcus bacteria over time where and average of 34% of samples collected annually 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). 43% of the samples collected from PC-BDDS exceeded the standard on an annual basis. 53% of the samples collected from PC-BDUS exceeded the standard on an annual basis. It should be noted that over the course of the past three years (2022-2024), the annual average of exceedances dropped to 23%. With few exceptions, Island Creek, Prince George Creek, Smith Creek, and Lords Creek have generally contained adequate levels of dissolved oxygen over the entire course of the program. Futch Creek has improved over recent years. Between 2008 to 2019, 20% of samples contained dissolved oxygen levels below the standard. However, between 2020 to 2024, only 8% of samples were below that standard. Barnards Creek has had varying dissolved oxygen levels over time. While not one sample was below the standard on 9 of the 17 years we’ve monitored, there were 4 years where at least 25% of the samples exceeded the standard (2014, 2015, 2016, 2022). Motts Creek has demonstrated relatively stable levels of dissolved oxygen with approximately 10% of the samples exceeding the standard over the entire course of the program. TABLE OF CONTENTS EXECUTIVE SUMMARY II Long Term Trends ii Key Takeaways iii INTRODUCTION 2 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 15 APPENDIX A: ADDITIONAL CREEK DATA 17 Barnards Creek 17 Futch Creek 19 Island Creek 24 Lords Creek 27 Motts Creek 29 Pages Creek 32 Prince George 36 Smith Creek 40 Airlie Gardens 45 APPENDIX B: LONG TERM TRENDS 50 Dissolved Oxygen 50 Turbidity 51 Chlorophyll-a 51 Enterococci 52 APPENDIX C 55 Improvement Efforts 55 APPENDIX D 57 Water Classifications 57 Parameter Definitions 57 Standards 60 Methods 63 LITERATURE CITED 64 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 the 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 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. 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 Average Exceedances Lifetime Past 5 Years  Dissolved oxygen (below 4) 2.5 0  Chlorophyll-a (above 40) < 1.0 < 1.0  Turbidity (above 50) < 1.0 0  Enterococci (above 500) 1.05 1   Overall Assessment Parameter BC-CBR  Turbidity (NTU) Good  Dissolved Oxygen Good  Chlorophyll-a Good  Enterococci Good  Chlorophyll-a levels exceeded the State standard once for the year. Overall, there were no issues with Barnards Creek for the year, however, Enterococci levels were generally higher compared to the previous two years. 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. Year at a Glance 6 (six) occurrences of dissolved oxygen below State standard 0 (zero) occurrences above State standard for chlorophyll-a 0 (zero) occurrences above State standard for turbidity 0 (zero) occurrences above State standards for Enterococci  Overall Assessment Parameter FC-4, FC-6, FC-13, FC-FOY  Turbidity (NTU) Good  Dissolved Oxygen Fair  Chlorophyll-a Good, Good, Fair, Fair  Enterococci Good  While dissolved oxygen levels exceeded the State standard on six (6) instances, overall, there were no other issues with Futch Creek for the year./ / Note: While fluctuations occur throughout the year, all levels for Enterococci at FC-13 were below state standards. 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. Year at a Glance 12 (twelve) occurrences of dissolved oxygen below State standard 1 (one) occurrences above State standard for chlorophyll-a 0 (zero occurrences above State standard for turbidity 0 (zero) occurrences above State standards for Enterococci  Parameter IC-HS, IC-SID  Turbidity (NTU) Good  Dissolved Oxygen Poor  Chlorophyll-a Good  Enterococci Good  Overall Assessment Dissolved oxygen was determined to be poor with 12 occurrences below the state standard. There was one occurrence of elevated chlorophyll-a at the Sidbury Road site, otherwise all other parameters were good. 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. Year at a Glance 1 (one) occurrence of dissolved oxygen below State standard 0 (zero) occurrences above State standard for chlorophyll-a 1 (one) occurrence above State standard for turbidity 0 (zero) occurrences above State standards for Enterococci  Overall Assessment Parameter LC-RR  Turbidity (NTU) Good  Dissolved Oxygen Good  Chlorophyll-a Good  Enterococci Good  There was only one occurrence of low dissolved oxygen and turbidity at the River Road site, otherwise water quality for the year at Lords Creek was good. / / Note: While fluctuations occur throughout the year, all levels for Enterococci at LC-RR were below state standards. 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. Year at a Glance 4 (four) occurrences of dissolved oxygen below State standard 1 (one) occurrence above State standard for chlorophyll-a 0 (zero) occurrence above State standard for turbidity 7 (seven) occurrences above State standards for Enterococci  Parameter MOT-CBR, MOT-ND  Turbidity (NTU) Good  Dissolved Oxygen Fair, Good  Chlorophyll-a Good  Enterococci Good, Poor  Overall Assessment Enterococci levels increased over the past year driven in part by years, there were six (6) exceedances at the Normandy Drive site. One (1) exceedance of the Chlorophyll-a level was observed at the Normandy Drive site as well. Pages Creek Parameter PC-BDDS, PC-BDUS, PC-M  Turbidity (NTU) Good  Dissolved Oxygen Poor, Good, Good  Chlorophyll-a Fair, Good, Good  Enterococci Poor, Fair, Good   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. Average Exceedances Lifetime Past 5 Years  Dissolved oxygen (below 4) 7.9 5.60  Chlorophyll-a (above 40) 1 < 1.0  Turbidity (above 50) 0 0  Enterococci (above 500) 12.24 9   Overall Assessment Dissolved Oxygen levels were below state standards five (5) times at PC-BDDS. Enterococci levels were poor at the PC-BDDS site where chlorophyll-a levels also exceeded the standard twice. One observation of elevated turbidity was noted at the PC-BDUS site. Prince George Creek Parameter PG-CH, PG-ML, PG-NC  Turbidity (NTU) Good  Dissolved Oxygen Poor  Chlorophyll-a Good  Enterococci Fair, Good, Good   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 Castle Hayne Road and N. College Road. Year at a Glance 20 (twenty) occurrences of dissolved oxygen below State standard 0 (zero) occurrences above State standard for chlorophyll-a 0 (zero) occurrences above State standard for turbidity 4 (four) occurrences above State standards for Enterococci  Overall Assessment Dissolved Oxygen at was below state standards throughout the year at all three sites. There were 3 exceedance for Enterococci at the Castle Hayne Road site and one at the North College site. Smith Creek Parameter SC-NK, SC-GR, SC-CD, SC-CH  Turbidity (NTU) Good  Dissolved Oxygen Poor, Good, Good, Good  Chlorophyll-a Good  Enterococci Good, Fair, Fair, Good   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. Year at a Glance 4 (four) occurrences of dissolved oxygen below State standard 1 (one) occurrence above State standard for chlorophyll-a 0 (zero) occurrences above State standard for turbidity 6 (six) occurrences above State standards for Enterococci  Overall Assessment Enterococci bacteria exceeded state standards three times at the Candlewood Drive site, twice at the Gordon Road site, and once at the North Kerr sites. Dissolved oxygen was below the state standard four times at the Gordon Road site. There was also one exceedance of chlorophyll-a at the North Kerr site. 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 5 (five) occurrences of dissolved oxygen below State standard 22 (twenty-two) occurrences above State standard for chlorophyll-a 0 (zero) occurrences above State standard for turbidity *Enterococci is not measured at Airlie Gardens  Overall Assessment Dissolved oxygen has remained fairly constant throughout the lake over the years despite occasional occurrences below the state standard. Orthophosphate and Nitrate/Nitrate levels moderated this year following several years of annual increases. Chlorophlly-a levels have remained relatively high over recent years indicating the presence of periodic algal blooms particularly when the water temperatures have been relatively warm. 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, as well 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 show 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 factors minimizing the impact to water quality. One factor may be the inclusion of state stormwater controls required for all new development which aims to mitigate stormwater on site. These stormwater control measures aim to reduce water quantity, which affects water quality. Additionally, the county in 2020 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 Cape Fear Public Utility Authority (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 2008 have experienced good water quality in terms of turbidity and chlorophyll-a levels over the course of 16 years of monitoring thus far (this does not include data from Island Creek due to the fact monitoring started just 3 years ago). The one parameter, however, that has been problematic has been Enterococci bacteria. Of the 3,604 samples collected and analyzed since June 2008, 763 samples (21%) have exceeded the State standard for this bacterium. This analysis does not include data from Island Creek which has only been monitored for the past several years and therefore was not included in the long-term dataset. 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 Over the past 16 years of water quality monitoring, 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 six (6) chlorophyll-a samples exceeded the State standard during the 2023-2024 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 six of the past seven years. Futch Creek has maintained a “Fair” rating for nine of the fifteen years, however improved and maintained a "Good" since the 2020-2021 monitoring period until it reverted back to “Fair” during the most recent sampling period. Pages Creek has demonstrated varying dissolved oxygen levels over time ranging from “Poor” to “Good” over the years and has been deemed “Fair” during seven of the past eight 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” fourteen of the sixteen years. It should be noted that the slow-moving water and swamp-like features within portions of Prince George 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 and Lords Creek), other creeks have proven to show elevated levels of Enterococci. Of the 3,664 samples collected and analyzed from all the monitoring sites since June 2008 (including those from Island Creek), 765 samples (21%) have exceeded the State standard for this bacterium. Specifically, Motts Creek has exceeded the standard 37% of the time and at Pages Creek, the down-stream site (PC-BDDS) and up-stream site (PC-BDUS) exceeded the standard 43% and 55% 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. Following two years of relatively low levels of Enterococci within the study area, this most recent year (2023-2024) demonstrated slightly worse water quality in terms of the indicator species of bacteria. Three creeks (Motts Creek, Prince George Creek, and Smith Creek) declined in ratings over the course of the past year. It should be noted, however, that no samples exceeded the State Enterococci standard during this most recent monitoring period from within Lords Creek, Futch Creek, and Barnards Creek. At Motts Creek, Pages Creek, Smith Creek, Prince George Creek, and Island Creek, the standard was exceeded 29%, 22%, 14%, 11%, and 8% of the time over the course of the 2023-2024 monitoring period, respectively. 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. Since that time, Motts Creek has demonstrated a “Fair” or “Good” ratings with the exception of this past year when higher levels of Enterococci were observed resulting in a “Poor” rating again. As mentioned above, despite this past year’s increase of bacteria in the watershed, the overall improvement in Enterococci levels 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). Since that time the data has reflected, that bacteria levels have generally been reduced 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 eight (8) 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 eight (8) samples that exceeded the standard, six (6) were from the Pages Creek Down-Stream Site (PC-BDDS) while two (2) were from the Pages Creek Up-Stream site (PC-BDUS). As mentioned above, since 2008, PC-BDDS and PC-BDUS exceeded the standard 43% and 55% of the time, respectively. However, over the past 4 sampling years between July 2020 and June 2024, the percentage of exceedances at both sites has decreased to 40%. Airlie Gardens Discussion The results from monthly sampling over the past eight 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 2015-2016 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 steadily increasing over time across all sites. Over the past eight 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. 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. Data from the 2023-2024 sampling period has revealed a reduction of orthophosphate and nitrate/nitrite levels at all three sites compared to the previous sampling period. Chlorophyll-a levels, however, have increased at all three sites during the 2023-2024 sampling period compared to last year. Therefore, it may be inferred that the nutrients that continue to enter the lake are taken up through plant growth and the creation of algal blooms. 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 2.3 mg/l and 8.6 mg/l with a mean value of 6.3 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 1.0 ug/l and 70.0 ug/l with a mean value of 9.0 ug/l at BC-CBR (Table 1). One sample surpassed the 40 ug/l standard. Enterococci ranged between 20 CFU/100 ml and 288 CFU/100 ml with a geometric mean value of 102 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 24 NTU with a mean value of 7 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. Table 1. Mean values of select parameters from Barnards Creek. Range in parentheses. Parameter BC-CBR  Turbidity (NTU) 7 (1-24)  Dissolved Oxygen (mg/l) 6.3 (2.3-8.6)  Chlorophyll-a (ug/l) 1 (1-70)  Enterococci (#CFU/100ml) 102 (20-288)  (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   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 4.2mg/l and 9.9 mg/l with a mean value of 7.2 mg/l (Figure 6 – Figure 9, Table 3). Six (6) samples contained dissolved oxygen levels below the State standard of 5.0 mg/l for SA water. Chlorophyll-a ranged between 0.0 ug/l and 33.0 ug/l with a mean value of 4.0 ug/l (Table 3). None of these values approached the 40ug/l chlorophyll-a standard. Enterococci ranged between 5 CFU/100ml and 31 CFU/100ml with a geometric mean value of 5 CFU/100ml. No samples 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 0 and 21 NTU with a mean value of 5 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 (1-21) 3 (0-15) 5 (1-17) 6 (1-21)  Dissolved Oxygen (mg/l) 7.4 (5.5-9.7) 7.3 (5.1-9.7) 7.0 (4.2-9.9) 7.1 (4.5-9.9)  Chlorophyll-a (ug/l) 5 (0-33) 3(0-8) 5 (1-13) 3 (0-7)  Enterococci (#CFU/100ml) 7 (5-10)1 5 (5-10)1 7 (5-30)1 7 (5-30)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 1.1 mg/l and 9.1 mg/l with a mean value of 4.6 mg/l (Table 5). Twelve (12) 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 43 ug/l with a mean value of 7 ug/l (Table 5). One (1) sample exceeded the State standard of 40 ug/l for chlorophyll-a. Enterococci ranged between 5 CFU/100ml and 3,610 CFU/100ml with a geometric mean value of 34 CFU/100ml (Table 5, Figures 17 and 18). Two (2) 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 30 NTU with a mean value of 7 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. Table 5. Mean values of select parameters from Island Creek. Range in parentheses. Parameter IC-HS IC-SID  Turbidity (NTU) 7 (2-30) 5 (1-16)  Dissolved Oxygen (mg/l) 4.9 (1.9-9.1) 4.2 (0.8-7.9)  Chlorophyll-a (ug/l) 5 (1-18) 8 (0-43)  Enterococci (#CFU/100ml) 43 (5-2,060)1 25 (5-3,610)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 3.5 mg/l and 10.4 mg/l with a mean value of 7.1 mg/l (Table 7). One (1) sample was below the State standard of 4.0 mg/l for C Sw waters during the sampling period (Figure 20). Chlorophyll-a ranged between 1 ug/l and 35 ug/l with a mean value of 11 ug/l (Table 7). No samples exceeded the State standard of 40 ug/l for chlorophyll-a. Enterococci ranged between 10 CFU/100ml and 75 CFU/100ml with a geometric mean value of 22 CFU/100ml (Table 7). None 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 4 and 51 NTU with a mean value of 21 NTU (Table 7). One (1) sample 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. Table 7. Mean values of select parameters from Lords Creek. Range in parentheses. Parameter LC-RR  Turbidity (NTU) 21 (4-51)  Dissolved Oxygen (mg/l) 7.1 (3.5-10.4)  Chlorophyll-a (ug/l) 11 (1-35)  Enterococci (#CFU/100ml) 22 (10-75)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 between1.8 mg/l and 9.1 mg/l with a mean value of 6.0 mg/l (Table 9). Four (4) samples collected during the reporting period contained dissolved oxygen levels below the standard (Figure 23 and Figure 24). Chlorophyll-a ranged between 1 ug/l and 43 ug/l with a mean value of 8 ug/l (Table 9). One (1) sample exceeded the 40ug/l standard. Enterococci ranged between 5 CFU/100ml and 6,490 CFU/100ml with a geometric mean value of 118 CFU/100 ml (Table 9). Samples exceeded the NCDEQ standard of 500 CFU/100 ml for Tier III waters during five (5)) sampling events during the reporting period (Figure 25 and Figure 26). Turbidity values were generally good ranging between 1 and 27 NTU with a mean value of 8 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. Table 9. Mean values of select parameters from Motts Creek. Range in parentheses. Parameter MOT-CBR MOT-ND  Turbidity (NTU) 5 (1-27) 4 (4-15)  Dissolved Oxygen (mg/l) 5.1 (2.7-7.9) 6.8 (1.8-9.1)  Chlorophyll-a (ug/l) 6 (1-31) 9 (1-43)  Enterococci (#CFU/100ml) 34 (5-620)1 405 (20-6,490)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 FAIR 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 2.8 mg/l and 11.9 mg/l with a mean value of 7.1 mg/l (Figures 28 - 30, Table 11). Over the twelve (12) month study period, the dissolved oxygen levels were below the State standard five (5) times at PC-BDDS while levels remained above the standard at PC-BDUS and PC-M. Chlorophyll-a ranged between 0 ug/l and 76 ug/l with a mean value of 10 ug/l (Table 11). Two (2) samples exceeded the State standard of 40 ug/l for chlorophyll-a. Enterococci ranged between 5 CFU/100 ml and 2,480 CFU/100 ml with a geometric mean value of 59 CFU/100 ml (Figures 31 – 33, Table 11). Six (6) samples from PC-BDDS and two (2) 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 1 and 28 NTU with a mean value of 7 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. It should be noted that the additional sampling at Pages Creek as part of the ongoing effort to locate the source of bacteria entering the creek can be found in Appendix D of this report. Table 11. Mean values of select parameters from Pages Creek. Range in parentheses. Parameter PC-BDDS PC-BDUS PC-M  Turbidity (NTU) 6 (1-10) 10 (1-28) 5 (1-10)  Dissolved Oxygen (mg/l) 6.0 (2.8-9.2) 7.9 (5.4-11.9) 7.3 (5.1-9.5)  Chlorophyll-a (ug/l) 16 (1-76) 9 (1-22) 6 (0-36)  Enterococci (#CFU/100ml) 303 (10-2,480)1 102 (20-404)1 7 (5-36)1  (1)Enterococci values expressed as geometric mean / Figure 28 Dissolved Oxygen at PC-BDDS at surface (DO-S) / Figure 29. Dissolved Oxygen at PC-BDUS at surface (DO-S) / Figure 30. Dissolved Oxygen at PC-M at surface (DO-S) and bottom (DO-B) / Figure 31. Enterococci at PC-BDDS / Figure 32. Enterococci at PC-BDUS / Figure 33. 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 POOR GOOD GOOD  Chlorophyll-a GOOD GOOD GOOD  Enterococci POOR FAIR 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 0.4 mg/l and 8.8 mg/l with a mean value of 4.3 mg/l (Table 13). Surface dissolved oxygen values were below the State standard of 4.0 mg/l for C Sw on seven (7) occasions during the reporting period at PG-NC and PG-ML and six (6) times at PG-CH (Figures 35 – 37, Table 13). Chlorophyll-a ranged between 1 ug/l and 16 ug/l with a mean value of 4 ug/l (Table 13). No samples from Prince George Creek exceeded the 40 ug/l standard. Enterococci ranged between 5 CFU/100ml and 3,870 CFU/100ml with a geometric mean value of 55 CFU/100ml (Table 13). Four (4) 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 8 NTU with a mean value of 3 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. Table 13. Mean values of select parameters from Prince George Creek. Range in parentheses. Parameter PG-CH PG-ML PG-NC  Turbidity (NTU) 4 (3-5) 2 (1-3) 4 (2-8)  Dissolved Oxygen (mg/l) 5.0 (2.4-8.8) 4.9 (3.1-7.7) 3.0 (0.4-6.4)  Chlorophyll-a (ug/l) 4 (1-7) 3 (1-8) 5 (1-16)  Enterococci (#CFU/100ml) 127 (20-3,280)1 61 (10-435)1 21 (10-3,870)1  (1)Enterococci values expressed as geometric mean / Figure 35. Dissolved Oxygen at PG-CH at surface (DO-S) and bottom (DO-B) / Figure 36. Dissolved Oxygen at PG-ML at surface (DO-S) / Figure 37. Dissolved Oxygen at PG-NC at surface (DO-S) and bottom (DO-B) / Figure 38. Enterococci at PG-CH / Figure 39. Enterococci at PG-ML / Figure 40. 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 FAIR 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). It should be noted that site SC-CH data was not available throughout the first half of the year due to the reconstruction of the bridge along Castle Hayne Road that crosses Smith Creek. Dissolved oxygen within the creek ranged between 1.1 mg/l and 10.2 mg/l with a mean value of 7.1 mg/l (Table 15; Figures 42 – 45). Four (4) samples collected were below the State standard. Chlorophyll-a ranged between 1 ug/l and 47 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 1,530 CFU/100 ml with a geometric mean value of 104 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 1 and 35 NTU with a mean value of 11 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. Table 15. Mean values of select parameters from Smith Creek. Range in parentheses. Parameter SC-CH SC-CD SC-GR SC-NK  Turbidity (NTU) 17 (10-35) 7 (1-22) 12 (3-31) 7 (3-12)  Dissolved Oxygen (mg/l) 7.5 (5.1-9.3) 8.3 (6.5-10.2) 5.7 (1.1-9.4) 6.9 (4.6-9.4)  Chlorophyll-a (ug/l) 4 (1-14) 6 (1-22) 6 (1-23) 18 (2-47)  Enterococci (#CFU/100ml) 54 (24-86) 220 (5-906)1 83 (10-826)1 93 (10-1,530)1  (1)Enterococci values expressed as geometric mean / Figure 42. Dissolved Oxygen at SC-CH at surface (DO-S) / Figure 43. 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 44. Enterococci at SC-CH / Figure 45. Enterococci at SC-CD / Figure 46. Enterococci at SC-GR / Figure 47. 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 GOOD GOOD POOR GOOD  Chlorophyll-a GOOD GOOD GOOD GOOD  Enterococci GOOD FAIR FAIR 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 serves 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 1.8 mg/l and 18.0 mg/l with a mean value of 7.8 mg/l (Table 17; Figures 51-53). Five (5) samples were below the State standard for dissolved oxygen. Turbidity values were generally good ranging between 1 and 49 NTU with a mean value of 10 NTU (Table 17). No samples exceeded the State standard of 50 NTU for Class C waters. Chlorophyll-a ranged from 2 mg/l to 293 mg/l with a mean value of 63 mg/l. The standard of 40 mg/l was exceeded twenty-two (22) times. / 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) 9 (1-37) 10 (3-30) 13 (2-49)  Dissolved Oxygen (mg/l) 6.3 (1.8-13.0) 9.4 (5.4-13.0) 7.6 (3.2-14.0)  Chlorophyll-a (mg/l) 59 (2-293) 71 (29-178) 58 (5-134)  Orthophosphate 0.07 (0.01-0.28) 0.04 (0.02-0.10) 0.08 (0.01-0.19)  Nitrate/Nitrite 0.10 (0.01-0.44) 0.02 (0.01-0.11) 0.06 (0.01-0.22)   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. During the 2016-2017 study period, Chlorophyll-a levels were similar at all three (3) sampling sites, however, the next year (2017-2018 study period) these levels were relatively higher at AG-IN compared to the two (2) sites situated in the central portion of the lake (AG-FD) and at the outfall location (AG-OUT). Since that time, however, the trend reversed, and higher levels of Chlorophyll-a was observed at AG-FD and AG-OUT compared to AG-IN (Figure 54). 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 49. Chlorophyll-a levels at Airlie Gardens Over Time When examining the levels of nutrients over time within these sampling sites, 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 nine (9) years, nitrite/nitrate levels have averaged 0.07 mg/l, 0.06 mg/l, and 0.04 mg/l at AG-IN, AG-FD, and AG-OUT, respectively. 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 have been similar across the lake over the past five years (Figure 56). Collectively, over the past nine (9) years of sampling, the average orthophosphate levels have been 0.07 mg/l at AG-IN 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. These levels increased to 0.10 mg/l and 0.17 mg/l, respectively during the 2022-2023 study period, however, these values decreased during the 2023-2024 sampling 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 50. Nitrate/Nitrate Levels in Airlie Gardens Over Time / Figure 51. Orthophosphate Levels in Airlie Gardens Over Time / Figure 52. 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 with the exception of AG-IN during the 2015-2016 and the previous2022-2023 study period. The levels at AG-FD and AG-OUT have been similar to each other each year and 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. / Figure 53. Dissolved Oxygen in Airlie Gardens Over Time 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 36%, 22%, 15%, and 10% of the time within Prince George Creek, Pages Creek, and Futch Creek, respectively. Dissolved oxygen was below the standard 9% of the time from within both Barnards Creek and Motts Creek while Smith Creek and Lords Creek exceeded the standard 6% and 5% of the time, respectively. Of the 550 samples that fell below the standard for dissolved oxygen the since 2008, 322 (58%), were observed during June, July, and August when water temperatures were the highest. / 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. 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. 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-one (21) times in total: eight (8) from within Pages Creek, seven (7) from within Smith Creek, two (2) from within Lords and 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. 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 38 exceedances of the chlorophyll-a standard were observed of the 3,189 samples collected. / Figure 61. Long-term chlorophyll-a data within tidal creeks Enterococci Figure 62 and Table 18 depict the long-term trends in Enterococci within the seven (7) 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 and Futch 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 43% and 55% of the time, respectively. Since June 2008, samples collected within Motts Creek, Pages Creek, and Smit Creek exceeded the State standard for Enterococci 37%, 35%, and 24% of the time, respectively Barnards Creek and Prince George Creek both exceeded the standard 21% of the time. Lords Creek exceeded the standard 8% of the time while Futch Creek has only exceeded the standard for Enterococci 3% of the time. / Figure 62. Long-term Enterococci data within tidal creeks 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  * Monitoring at Island Creek began in program year 2021-2022 APPENDIX C Improvement Efforts While urbanization and development can be factors impacting water quality, the ratings for many water quality parameters as depicted in this report have improved 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 minimizing the impact to water quality. While these factors facilitating this trend have not been identified, several notable efforts maybe contributing to these improvements. Efforts made by New Hanover County over the years to improve water quality include property acquisition using grant and trust fund sources, working with the Cape Fear Public Utility Authority (CFPUA) to test sewer infrastructure, the installation of stormwater Best Management Practices (BMPs) such as raingardens, infiltration basins, and impervious surface retrofits, and microbial source tracking. Much of the effort in recent years has been to investigate and determine the source of bacteria within the Pages Creek watershed. 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. In 2008 and 2013 source tracking studies were performed identifying a human signature in the bacteria that was present in the waters at the PC-BDUS site within Pages Creek. In coordination, the New Hanover County Health Department and the Cape Fear Public Utility Authority, investigated abandoned septic systems and conducted inspections of sewer infrastructure to determine if those were a contributing factor to the elevated bacteria levels. These investigations did not reveal any deficiencies. In 2019, New Hanover County partnered with the University of North Carolina Wilmington’s Socio-Environmental Analysis Laboratory and CPE to conduct a thermal imagery scan of two portions of the creek adjacent to monitoring sites that have consistently detected elevated levels of Enterococci bacteria. Following the flight, University of North Carolina Wilmington and CPE analyzed the imagery and identified two areas depicting thermal anomalies in proximity to the two long term monitoring sites. These thermal anomalies, once ground truthed, revealed several subterranean groundwater seeps entering the creek from the streambank. As a result of those investigations, in 2022, planning staff, CPE, and the Cape Fear Public Utility Authority coordinated to perform additional testing of the seep water coming from the creek bank in two locations where the thermal imagery showed temperature differences indicating the presence of point-source effluent entering the creek. These areas were characterized as groundwater seeps located along the creek’s bank visualized only at lower tides. Samples collected in proximity to PC-BDUS resulted in a “Non-Detect” where the host-associated fecal gene biomarker (HF183) were not detected in one or both test replicates. The two samples collected from the seep located in proximity to the PC-BDDS resulted in “Detected, Not Quantified” where the host-associated fecal biomarker was detected in both test replicates but in quantities below the limit of quantification. In June and July of 2023 the county partnered with Coastal Protection Engineering to broaden the geographic extent of source tracking testing in Pages Creek in an attempt to determine if any additional areas within the creek contained human-borne bacteria and narrow down locations where bacteria is entering into the creek. Twenty (20) additional testing sites located throughout the watershed were sampled twice on a falling tide, once during a dry period and once following a rain event, for a total of forty (40) samples. This method would provide an opportunity to identify if the contamination was widespread or concentrated within specific geographic areas in the watershed. After collection, samples were sent to an analytical laboratory to determine the presence concentration of human-borne fecal bacteria. This additional testing resulted in the identification of human signatures during both sampling events which, again, confirmed the presence of human borne bacteria within the creek. The results also indicated that the location of bacteria entering the creek is limited to an area in proximity to the two long-term monitoring sites, Pages Creek Up-Stream and Pages Creek Down-Stream (PC-BDUS and PC-BDDS). The results of the expanded testing can be found in 2023-2023 New Hanover County Water Quality Monitoring Program report. Since those efforts 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. In the past year the Cape Fear Public Utility Authority has videoed pipe in the Bayshore community to visually inspect the lines. No deficiencies were found during that inspection however, a sewer system overflow (SSO) in August of 2024 was reported resulting in the replacement of a section of pipe. In addition, as part of the Cape Fear Public Utility Authorities Capital Imrpvement Plan the pump station located adjacent to the PC-BDUS site is scheduled for a capacity upgrade. Improvements to infrastructure has been noted to decrease bacteria levels. In July of 2024 the New Hanover County Soil and Water Conservation District with the assistance from ENTER FIRM NAME completed a Pages Creek Restoration Plan. The plan outlines potential strategies to help curb bacteria loading into the creek as well as help to reduce nutrient loading into the creek. The restoration plan now allows for New Hanover County to partner with property owners and apply for federal dollars to fund implementation projects installed on homeowners properties. The idea is to work with the community and install retrofits that can mitigate non-point-source and point-source pollution and impacts from stormwater and flooding. 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. These initiatives include installing several aerators in the lake to increase the dissolved oxygen levels, restore a wetland area near the entry point where water enters the lake and the completion of a dredging operation effectively removing approximately 4,000 cubic yards of bottom sediment and material. The county continues to monitor the lake as it may take several years for a data trend to emerge. Data from this past year, however, has not indicated a reduction in nutrient loading into the lake. 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 “Sw” supplemental classification indicates that these are swamp waters, and so are likely to have lower dissolved oxygen and pH than non-swamp streams due to natural conditions. However, a majority of the sites, including Lords Creek, Motts Creek, Barnards Creek, Smith Creek, and Prince 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/da ta/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. 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