NATURAL ENVIRONMENT

NATURAL ENVIRONMENT 6

Dissolved Oxygen maximum 5mg/L T his section focuses on air and water quality. In considering air quality, concen- Temperature maximum 32 degrees trations of carbon monoxide and ozone are Celsius used as parameters. Air quality is regional pH between 6 and 9 pH units because of air’s properties of dispersal. Turbidity maximum 50 NTU Also the only local air quality monitor is in Dissolved Solids maximum 500mg/L downtown Chapel Hill. Therefore, we use ozone concentration values from the Trian- Fecal Coliforms maximum count 200/100mL gle ozone forecast area and carbon monox- ide concentration values from Chapel Hill. Phosphorus recommended maximum 0.5mg/L Water quality parameters are more com- Nitrite & Nitrate maximum 10mg/L plete than air quality data, in terms of pol- Ammonia recommended maximum lutants measured (13). Water quality sam- 2mg/L ples are collected at 13 monitoring sites in Lead maximum 25µg/L Chapel Hill and Carrboro (see Map 2) at low-flow conditions. Thirteen water qual- Zinc maximum 50 µg/L ity parameters are measured, but only those that have statutory or recommended standards defined by the North Carolina HIGHLIGHTS Division of Environmental Management will be presented here. · Based on Air Quality Index Values, a measure of ground-level ozone, There are limitations to the use of these particulate matter, carbon monoxide, data. Collection methods do not conform sulfur dioxide, and nitrogen dioxide, to the North Carolina state sampling meth- the Raleigh-Durham-Chapel Hill area odology or frequency recommendations. experienced just one “unhealthful” day Only approximate comparisons can be in 2003 compared to four in 2000. The made to NC state water quality standards. number of “moderate” days in 2003 The standards used in the three-year sum- totaled 153, thirty five days fewer than mary charts on pages 9 through 13 are as the total for 2000 (see Figure 2 on Page follows: 6.5).

2004 CHAPEL HILL DATA BOOK 6.1 NATURAL ENVIRONMENT

· Water quality standards for tempera- Understanding of nutrient sources and ture, zinc, and lead have not been ex- transport may become important for the ceeded in the past 3 years. Shading of Town as more strict nutrient standards streams maintains a lower temperature, are developed to maintain water quality and most streams in Chapel Hill are for Jordan Lake as a drinking water shaded to some degree. Zinc and lead source. in water are indicators of auto-related pollution, specifically from gasoline and · Turbidity of water quality samples is car batteries. Both are very rarely de- generally low, as would be expected tected in surface water in the past three during low-flow sampling. Sampling years, and never exceed the standard. after storms or during other high-flow events would better indicate the degree · Water quality samples are below the of bank erosion and sediment transport standard for dissolved oxygen less in occurring in area streams. 2003 than in 2002 (the height of the most recent drought), yet still elevated · Evidence of sedimentation in streams above 2001. (see figure 12) indicates that this may be one of the more important characteris- · Water quality samples above the stan- tics impairing stream health in Chapel dard for fecal coliforms are frequent Hill. Hydrologic factors affecting ero- among all sites, and show no strong sion and sedimentation, such as veloc- trend over the past three years. Con- ity and the discharge profile, are impor- current measurement of ammonia is tant for determining the cause of sedi- taken which can help to differentiate ment problems. A model of stream between human and animal sources. scour in the Chapel Hill area is being Tracing the source of these organisms developed as part of the Town’s in- will be a part of the Town’s Storm- volvement in the Little and Morgan water Management Program * Creeks Watershed Planning Initiative. . * The Town of Chapel Hill is undertak- · Measurements of nitrite and nitrate are ing a new program to manage storm- generally low for most sites. Site 3, water and related water resources is- Morgan Creek at the Ford, has a history sues within its jurisdiction. Visit town- of elevated nitrogen levels. This is to be ofchapelhill.org/stormwater which de- expected because the OWASA treat- scribes the many water resource-related ment plant is upstream of this site. projects and issues the Town is in- However, too few samples are taken for volved in. most sites (two in 2003 for each site ex- cept for Carrboro sites) to determine In June 2004, the Town adopted an ordi- any trends in nitrate and nitrite. More nance which established a Storm-water frequent sampling of nutrients would Management Utility, and provided for be necessary to determine base levels the appointment of a Stormwater Man- and trends. agement Utility Advisory Board for the Town of Chapel Hill.

6.2 2004 CHAPEL HILL DATA BOOK NATURAL ENVIRONMENT

Map 1: Raleigh-Durham-Chapel Hill Ozone Monitoring Sites

Key

H - Rte. 4, Pittsboro O - 2700 N. Duke St., Durham V - 431 S. Hillsborough St., Franklinton AA - 1338 Jack Road, Clayton AB - Highway 301 & SR 2141 AR - 201 N. Broad St., Fuquay- Varina AS - 5033 TV Tower Road, Gar- ner AT - 808 North State St. Raleigh AU - 3801 Spring Forest Road, Raleigh

Figure 1: Annual Ozone Exceedance Days in Raleigh-Durham-Chapel Hill Region

45 39 40 35 29 29 30 24 25

Days 20 15 12 10 8 8 5 0 1997 1998 1999 2000 2001 2002 2003

Annual Ozone Exceedance Days

2004 CHAPEL HILL DATA BOOK 6.3 NATURAL ENVIRONMENT

Figure 2: Pollutant Standards Index Daily Values, Raleigh-Durham-Chapel Hill

1998

2003

Index Meaning Broad categories of potential health effects due to the major air pollutants — ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide — are associated with ranges of AQI values. The health effects categories are: · Good when AQI is less than 50 · Moderate when AQI is 50 to 100 · Unhealthful when AQI is greater than 100 · Very unhealthful when AQI is greater than 200 · Hazardous when AQI is greater than 300

6.4 2004 CHAPEL HILL DATA BOOK NATURAL ENVIRONMENT

Table 1: Air Quality Index Summary for Triangle Region and Orange County, 2003

Raleigh- Durham- Orange Wake Durham Franklin Johnson Chatham

Chapel Hill County County County County County County MSA # Days with Air Quality Index 365 84 364 309 211 211 243 Number of Days when Air Quality was… Good 204 53 215 211 180 188 211 Moderate 153 31 142 93 27 21 31 Unhealthy for Sensitive Groups 7 0 6 5 4 2 1 Unhealthy 1 0 1 0 0 0 0 Air Quality Index Statistics Maximum 177 99 177 135 124 116 114 90th Percentile 72 64 71 66 64 54 57 Median 47 42 46 39 38 36 35 Number of Days when Air Quality Index pollutant was… CO 7 0 7 0 0 0 0 NO2 0 0 0 0 0 0 0 O3 87 0 87 113 211 211 170 SO2 0 0 0 0 0 0 0 PM2.5 271 84 270 185 0 0 73 PM10 0 0 0 11 0 0 0

Number of Days when Air Quality was…. These rows indicate how the daily AQI values for Orange county or the Raleigh Durham Chapel Hill MSA were distributed among four broad categories of air quality: Good: Number of days in the year having an AQI value 0 through 50. Moderate: Number of days in the year having and AQI value 51 through 100. Unhealthy for Sensitive Groups : Number of days in the year having an AQI value 101 through 150. Unhealthy: Number of days in the year having an AQI value 151 or higher. This includes the AQI categories unhealthy, very un- healthy, and hazardous. Very few locations (about 0.3% of counties) have any days in the very unhealthy or hazardous categories. Median : Half of daily AQI values during the year were less than or equal to the median value, and half equaled or exceeded it. Number of Days when AQI pollutant was…. A daily index value is calculated for each air pollutant measured. The highest of those index values is the AQI value, and the pollutant responsible for the highest index value is the "Main Pollutant." The criteria pollutants used to calculate AQI are: CO - Carbon monoxide NO2 - Nitrogen dioxide O3 - Ozone SO2 - Sulfur dioxide PM2.5 - Particulate matter smaller than 2.5 micrometers PM10 - Particulate matter smaller than 10 micrometers

Source: U.S. Environmental Protection Agency. Air Data

2004 CHAPEL HILL DATA BOOK 6.5 NATURAL ENVIRONMENT

Table 2: Research Triangle Region Air Pollution Inventory 1990 (Tons per Day)

% of Pollutant / Source Chatham Durham Orange Wake TOTAL Total Volatile Organic Compounds1 (VOC's) Tons / Day Mobile (Cars & Trucks) 3.3 14.2 7.4 36.2 61.1 41.4% Non-Road Mobile (Heavy Equipment) 1.1 5.1 2.6 13.4 22.2 15.1% Area (Gas Stations, Dry Cleaners, etc.) 5.9 13.6 6.0 24.8 50.3 34.1% Point (Factories and Utilities) 1.7 4.4 0.0 7.8 13.9 9.4% TOTAL 12.0 37.3 16.0 82.2 147.5 100.0% % of Total 8.1% 25.3% 10.8% 55.7% 100.0% NA

Nitrogen Oxides1 (NOX) Tons / Day Mobile (Cars & Trucks) 4.2 18.8 11.5 43.8 78.3 63.0% Non-Road Mobile (Heavy Equipment) 1.1 4.3 2.1 13.8 21.3 17.1% Area (Gas Stations, Dry Cleaners, etc.) 0.6 1.2 0.6 2.7 5.1 4.1% Point (Factories and Utilities) 15.9 0.9 0.9 1.8 19.5 15.7% TOTAL 21.8 25.2 15.1 62.1 124.2 100.0% % of Total 17.6% 20.3% 12.2% 50.0% 100.0% NA Carbon Monoxide (CO) Tons / Day Mobile (Cars & Trucks) 23.3 110 61 258.6 452.9 69.1% Non-Road Mobile (Heavy Equipment) 7.8 36.3 18.9 90.7 153.7 23.4% Area (Gas Stations, Dry Cleaners, etc.) 19.1 4.1 7.8 15.2 46.2 7.0% Point (Factories and Utilities) 1.9 0.3 0.2 0.6 3 0.5% TOTAL 52.1 150.7 87.9 365.1 655.8 100.0% % of Total 7.9% 23.0% 13.4% 55.7% 100.0% NA Source: North Carolina Department of Environment, Health and Natural Resources, Division of Air Quality 1. Man-made sources only (i.e. not including biogenic sources).

Figure 3: Research Triangle Region Air Pollution Inventory by County 1996

60%

50%

40%

30% 20%

10%

0% Volatile Organic Compounds Nitrogen Oxides Carbon Monoxide

Orange Chatham Durham Franklin Johnston Wake

Source: 1996 National Emission Trends database

6.6 2004 CHAPEL HILL DATA BOOK NATURAL ENVIRONMENT

Table 3: Orange County Emissions Pollutant measured in tons, 1996 & 1999

(% of US 1996 1999 total) CO 1,217 1,045 0% NOX 289 657 0% VOC 84 120 0% SO2 239 217 0% PM2.5 45 13 0% PM10 57 25 0% NH3 0 0 0%

Key: Pollutants NOx - oxides of nitrogen; tons per year; VOC - volatile organic compounds; tons per year; CO - carbon monoxide, tons per year; PM10 - directly emitted particulate matter <10; SO2 - sulfur dioxide, tons per year Source: U.S. Environmental Protection Agency. Air Data

2004 CHAPEL HILL DATA BOOK 6.7 NATURAL ENVIRONMENT

Map 2: Water Quality Monitoring Sites

6.8 2004 CHAPEL HILL DATA BOOK NATURAL ENVIRONMENT

Figure 4 Water Quality Samples Exceeding NC Standard for Dissolved Oxygen 2001 - 2003

12

10

8

6

4 Number of Samples

2

0 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003

site 1 site 2 site 3 site 4 site 5 site 6 site 7 site 8 site 9 site 10 site 11 site 12 site 13 Some of the measurements in 2003 may have been artificially low due to a malfunctioning dissolved oxygen probe.

Legend Samples Exceeding NC Standard Total Number of Samples Figure 5

Water Quality Samples Exceeding NC Standard for pH 2001 - 2003

12

10

8

6

Number of Samples 4

2

0 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003

site 1 site 2 site 3 site 4 site 5 site 6 site 7 site 8 site 9 site 10 site 11 site 12 site 13

2004 CHAPEL HILL DATA BOOK 6.9 NATURAL ENVIRONMENT

Figure 6 Water Quality Samples Exceeding NC Standard for Turbidity 2001 - 2003

12

10

8

6

4 Number of Samples

2

0 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003

site 1 site 2 site 3 site 4 site 5 site 6 site 7 site 8 site 9 site 10 site 11 site 12 site 13 Legend Samples Exceeding NC Standard Total Number of Samples Figure 7

Water Quality Samples Exceeding NC Standard for Dissolved Solids 2001 - 2003

12

10

8

6

4 Number of Samples

2

0 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003

site 1 site 2 site 3 site 4 site 5 site 6 site 7 site 8 site 9 site 10 site 11 site 12 site 13

6.10 2004 CHAPEL HILL DATA BOOK NATURAL ENVIRONMENT

Figure 8 Water Quality Samples Exceeding NC Standard for Fecal Coliforms 2001 - 2003

12

10

8

6

Number of Samples 4

2

0 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003

site 1 site 2 site 3 site 4 site 5 site 6 site 7 site 8 site 9 site 10 site 11 site 12 site 13

Legend Samples Exceeding NC Standard Total Number of Samples

Figure 9

Water Quality Samples Exceeding NC Standard for Phosphorus 2001 - 2003

12

10

8

6

Number of Samples 4

2

0 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003

site 1 site 2 site 3 site 4 site 5 site 6 site 7 site 8 site 9 site 10 site 11 site 12 site 13

2004 CHAPEL HILL DATA BOOK 6.11 NATURAL ENVIRONMENT

Figure 10 Water Quality Samples Exceeding NC Standards for Nitrite and Nitrate 2001 - 2003

12

10

8

6

Number of Samples 4

2

0 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003

site 1 site 2 site 3 site 4 site 5 site 6 site 7 site 8 site 9 site 10 site 11 site 12 site 13

Legend Samples Exceeding NC Standard Total Number of Samples

Figure 11 Water Quality Samples Exceeding NC Standard for Ammonia 2001 - 2003

12

10

8

6

Number of Samples 4

2

0 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003

site 1 site 2 site 3 site 4 site 5 site 6 site 7 site 8 site 9 site 10 site 11 site 12 site 13

6.12 2004 CHAPEL HILL DATA BOOK NATURAL ENVIRONMENT

Figure 12

Water Quality Samples Exceeding NC Standard for Suspended Solids 2001 - 2003

12

10

8

6

4 Number of Samples

2

0 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003 2001 2002 2003

site 1 site 2 site 3 site 4 site 5 site 6 site 7 site 8 site 9 site 10 site 11 site 12 site 13

Legend Samples Exceeding NC Standard Total Number of Samples

ABOUT THE WATER QUALITY DATA Chapel Hill's water quality sampling program does not conform to the NC State sampling methodology or frequency, therefore results are only an approximation compared to NC water quality standards. Water quality samples were generally taken at one month intervals and were not correlated to flow.

The sources for all water quality data (Figures 4 through 12) are the Chapel Hill Engineering Department, DENR Division of Wa- ter Quality, state Fresh Surface Water Standards, and the Chapel Hill Planning Department.

2004 CHAPEL HILL DATA BOOK 6.13 NATURAL ENVIRONMENT

Table 4: Chapel Hill Bioclassification Summary According to NC Benthic Macroinverte- brate Stream Survey

Bioclassification NC Benthic Macroinverte- CH WQ Monitoring Apr- Feb-93 Apr-93 Feb-98 Mar-98 Trend brate Sampling Site Site 86 Morgan Creek at NC Site 1 NS 2.5 2.0 NS 2.5 Inconclu- Botonic. Garden sive Meeting of the Waters Creek Site 2 NS NS 1.0 NS 1.0 Neutral at Laurel Hill Road Bolin Creek at Umstead Park Site 4 NS NS 2.5 3.0 NS Positive Bolin Creek at East Franklin Site 5 2.5 2.0 NS 1.0 2.0 Negative St. Little Creek at Pinehurst Site 6 NS 2.0 NS 1.0 NS Negative Drive Morgan Creek at NC 54 Site 7 NS 4.0 NS 3.5 NS Negative Booker Creek at Piney Site 8 NS NS NS NS 2.0 NA Mountain. Road Morgan Creek below Site 3 NS 2.0 NS NS 2.0 Neutral OWASA Wastewater Plant Bolin Creek at Homestead NA NS NS 3.0 NS 3.0 Neutral Rd. Source: Chapel Hill Engineering Department, DEHNR Division of Water Quality; NC Fresh Surface Water Standards, Chapel Hill Planning Department Bioclassification: 4 = Excellent, 3.5 = Excellent/Good, 3 = Good, 2.5 = Good/Fair, 2 = Fair, 1.5 = Fair/ Poor, 1 = Poor, NS = No Sample.

In June 2003 North Carolina Department of Environment and Natural Resources Division of Water Quality published an assessment report:”Biological Impairment in the Little Creek Watershed which includes some samples for the above listed sites. For more information please visit http://townhall.townofchapelhill.org/ stormwater/wtr_quality.html

6.14 2004 CHAPEL HILL DATA BOOK