U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2008–1156

Prepared in cooperation with the U.S. Environmental Protection Agency National Risk 

Management Research Laboratory

Microbial and Nutrient Concentration and Load Data During 

Stormwater Runoff at a Swine Concentrated Animal Feeding 

Operation in the North Carolina Coastal Plain, 2006–2007

Microbial and Nutrient Concentration and 

Load Data During Stormwater Runoff at 

a Swine Concentrated Animal Feeding 

Operation in the North Carolina Coastal 

Plain, 2006–2007

By Stephen L. Harden

Prepared in cooperation with the U.S. Environmental Protection Agency 

National Risk Management Research Laboratory

Open-File Report 2008–1156

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2008

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Suggested citation:

Harden, S.L., 2008, Microbial and nutrient concentration and load data during stormwater runoff at a swine 

concentrated animal feeding operation in the North Carolina Coastal Plain, 2006–2007: U.S. Geological 

Survey Open-File Report 2008–1156, 22 p. (only online at http://pubs.water.usgs.gov/ofr2008-1156/)
iii

Contents

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Purpose and Scope ..............................................................................................................................1

Description of Study Area ...................................................................................................................1

Methods...........................................................................................................................................................4

Data Summary................................................................................................................................................5

Stormwater-Runoff Sampling Events ................................................................................................5

Water Stage and Flow..........................................................................................................................7

Microbial and Nutrient Concentrations and Loads.........................................................................7

Acknowledgments.......................................................................................................................................19

References Cited..........................................................................................................................................19

Appendix—Summary of nutrient and analytical results for stormwater event samples

 collected at the Lizzie Research Site, Greene County, North Carolina, 2006–2007 ....20

Figures

1. Location of study area in the Neuse River basin, North Carolina ........................................2

2. Surface-water, tile-drain, and overland flow runoff locations and rain-gage 

site at the Lizzie Research Site, Greene County, North Carolina..........................................3

3. Stage recorder and ISCO sampler instrumentation at ditch site SR5–D1

and tile site SR5–T1, Lizzie Research Site, Greene County, North Carolina .......................5

4. Daily total precipitation at site WS2 (USGS station number 353137077332801), 

Lizzie Research Site, Greene County, North Carolina.............................................................6

5. Daily mean gage heights at sites S7, S2, SR5–D1, and SR5–T1 at the Lizzie 

Research Site, Greene County, North Carolina .......................................................................8

6. Instantaneous loads of nitrite plus nitrate, Eschericia coli, and enterococci for 

sampling event 1, June 14–19, 2006, Lizzie Research Site, Greene County, 

North Carolina .............................................................................................................................15

7. Instantaneous loads of nitrite plus nitrate, Eschericia coli, and enterococci 

for sampling event 2, July 23–24, 2006, Lizzie Research Site, Greene County, 

North Carolina .............................................................................................................................16

8. Instantaneous loads of nitrite plus nitrate, Eschericia coli, and enterococci 

for sampling event 3, October 17–19, 2006, Lizzie Research Site, Greene County, 

North Carolina .............................................................................................................................17

9. Instantaneous loads of nitrite plus nitrate for sampling event 4, October 27–29, 

2006, Lizzie Research Site, Greene County, North Carolina.................................................18

10. Instantaneous loads of Eschericia coli and enterococci for sampling event 5, 

June 3–4, 2007, Lizzie Research Site, Greene County, North Carolina ..............................18

Tables

1. Precipitation and stormwater-runoff monitoring locations at the Lizzie Research 

Site, Greene County, North Carolina, 2006–2007 .....................................................................4

2. Summary of stormwater-runoff event sampling at the Lizzie Research Site, 

Greene County, North Carolina, 2006–2007 ..............................................................................6
iv

3. Concentrations and loads for site S7, Greene County, North Carolina, 

2006–2007 .......................................................................................................................................9

4. Concentrations and loads for site S2, Greene County, North Carolina, 

2006–2007 .....................................................................................................................................11

5. Concentrations and loads for site SR5–D1, Greene County, 

North Carolina, 2006–2007.........................................................................................................13

6. Concentrations and loads for site SR5–T1, Greene County, 

North Carolina, 2006–2007.........................................................................................................14

Conversion Factors

Inch/Pound to SI

Multiply By To obtain

Length

foot (ft) 0.3048 meter (m)

Area

square mile (mi2) 2.590 square kilometer (km2) 

Flow rate

gallon per minute (gal/min) 0.06309 liter per second (L/s)

SI to Inch/Pound

Multiply By To obtain

Volume

liter (L) 2.113 pint (pt)

liter (L) 1.057 quart (qt)

Mass

gram (g) 0.03527 ounce, avoirdupois (oz)

Water-quality measurements are given in metric units.

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88).

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Abbreviations and Acronyms

CAFO concentrated animal feeding operation

EPA U.S. Environmental Protection Agency

E. coli Eschericia coli

mL milliliter

MPN/100 mL most probable number per 100 milliliters

NCDENR DWQ North Carolina Department of Environment and Natural Resources, 

 Division of Water Quality

NRMRL National Risk Management Research Laboratory

PZF point of zero flow
Abstract

This report summarizes water-quality and hydrologic 

data collected during 2006–2007 to characterize bacteria and 

nutrient loads associated with overland runoff and subsurface 

tile drainage in spray fields at a swine concentrated animal 

feeding operation. Four monitoring locations were established 

at the Lizzie Research Site in the North Carolina Coastal Plain 

Physiographic Province for collecting discharge and waterquality data during stormwater-runoff events. Water stage 

was measured continuously at each monitoring location. A 

stage-discharge relation was developed for each site and was 

used to compute instantaneous discharge values for collected 

samples. Water-quality samples were collected for five storm 

events during 2006–2007 for analysis of nutrients and fecal 

indicator bacteria. Instantaneous loads of nitrite plus nitrate, 

total coliform, Escherichia coli (E. coli), and enterococci were 

computed for selected times during the five storm events.

Introduction

Several phases of scientific investigations at the Lizzie 

Research Site in the Contentnea Creek subbasin of the Neuse 

River, NC (fig. 1), have been conducted through collaborative 

efforts between the North Carolina Department of Environment and Natural Resources Division of Water Quality 

(NCDENR, DWQ), the U.S. Environmental Protection Agency 

(EPA), and the U.S. Geological Survey (USGS) to characterize 

the site and identify contaminant fate and transport processes 

occurring in the watershed. Results of previous investigations 

conducted at the Lizzie Research Site are discussed by Harden 

and Spruill (2004, 2008), Spruill and others (2005), Tesoriero 

and others (2005), and Walker and others (2008).

In 2003, EPA initiated a study at the Lizzie Research Site 

to examine the environmental implications of spray fields as a 

component of typical waste-management strategies in commercial hog production. The focus of the EPA project was to 

assess water-quality changes in adjacent streams that receive 

runoff from an agricultural field sprayed with hog waste and to 

monitor air-quality changes resulting from the local transport 

of airborne ammonia (Walker and others, 2008). During 

2006–2007, the EPA, NCDENR, and USGS conducted a 

cooperative study at the Lizzie Research Site to better 

understand the release of microorganisms and nutrients into 

the watershed through overland runoff and subsurface drains 

(commonly referred to as tile drains) from a swine concentrated animal feeding operation (CAFO) using spray-field 

waste-treatment technology. 

Purpose and Scope

This report summarizes the analytical and hydrologic 

data collected during February 2006–September 2007 at 

four monitoring locations at the Lizzie Research Site. Data 

compiled in this report support one of the principal objectives 

of the ongoing research at the study site to characterize 

bacteria and nutrient loads associated with overland runoff and 

subsurface drainage from spray fields at the swine CAFO. The 

stage-discharge relation determined for each site was used to 

compute instantaneous discharge values for collected samples. 

Instantaneous loads of nitrite plus nitrate, total coliform, 

Escherichia coli (E. coli), and enterococci were computed for 

selected times during five stormwater-runoff events. 

Description of Study Area

The Lizzie Research Site is located in Greene County, 

in the North Carolina Coastal Plain Physiographic Province, 

south of the confluence of Sandy Run and Middle Swamp 

(figs. 1, 2). Most of the site is drained by a first-order stream, 

known locally as Plum Tree Branch, which is a tributary to 

Sandy Run and drains 0.59 square miles (mi2). Land use in the 

area is primarily agricultural, with row crops typically of corn, 

Microbial and Nutrient Concentration and Load Data 

During Stormwater Runoff at a Swine Concentrated 

Animal Feeding Operation in the North Carolina 

Coastal Plain, 2006–2007

By Stephen L. Harden
2 Microbial and Nutrient Concentration and Load Data During Stormwater Runoff at a Swine CAFO in the Coastal Plain

Figure 1. Location of study area in the Neuse River basin, North Carolina.

WILSON

NASH

MARTIN

BERTIE

GREENE

EDGECOMBE

SAMPSON JONES

WAYNE

JOHNSTON

WAKE

FRANKLIN

LENOIR

PITT

CRAVEN

BEAUFORT

78 77

Generalized physiographic province line

Basin boundary

EXPLANATION

Greenville

Neuse

River

Basin

Washington

New Bern

BLUE RIDGE

PIEDMONT COASTAL PLAIN

LOCATION OF STUDY AREA, PHYSIOGRAPHIC PROVINCES, AND THE NEUSE RIVER BASIN IN NORTH CAROLINA

0 25 MILES

0 25 KILOMETERS

36

35

Figure 1. Location of study area in the Neuse River basin, North Carolina. 

Kinston

Bear

Little Contentnea

Contentnea

Cr.

Cr.

Creek

Neuse

River

Area enlarged

in figure 2
Introduction 3

Figure 2. Surface-water, tile-drain, and overland flow runoff locations and rain-gage site at the Lizzie Research Site, 

Greene County, North Carolina.

S7

S7

SR5-T1

S2

SR5-T1

SR5-D1

Sandy

Run

Plum Tree

Branch

Spray

fields

Non-spray

field

Waste

lagoon

Middle

Swamp

Non-spray

field

3531’

3531’30”

3532’

77 77 33’30” 34’ 77

33’

EXPLANATION

Base from digital files of

U.S. Geological Survey

Digital Raster Graph, Farmville Quad

1:24,000

Figure 2. Surface-water, tile-drain, overland flow runoff locations and rain gage site at the Lizzie Research Site,

Greene County, North Carolina.

0 2,000 4,000 FEET

0 500 1,000 METERS

Riparian

buffer

HALF MOON POCOSIN

Surface-water sampling site and number

Tile-drain sampling site and number

Overland flow runoff sampling site and number

Rain gage

Field ditch

Hog houses

WS2

SR5-D1

WS2
4 Microbial and Nutrient Concentration and Load Data During Stormwater Runoff at a Swine CAFO in the Coastal Plain

wheat, and soybeans. Agricultural fields at the site consist of 

somewhat poorly drained to well-drained soils.

Farming practices at the Lizzie Research Site changed 

during the mid-1990s. Prior to 1995, crops were fertilized 

using conventional inorganic fertilizer. In 1995, a swine CAFO 

with five hog houses and a waste lagoon was placed in operation at the site. After 1995, fertilizing practices shifted from 

the use of conventional inorganic fertilizers to field spraying of 

lagoon effluent from the swine operation.

Methods

During the study, rainfall was monitored at site WS2, 

and a network of automated water-quality samplers and 

water-stage recorders was utilized at four locations along 

Plum Tree Branch for obtaining water-quality information 

(table 1; fig. 2). The four sampling locations included stream 

sites S7 (upstream) and S2 (downstream), overland runoff 

site SR5–D1, and tile-drain site SR5–T1. The weather-station 

site WS2 (USGS station name: Weather station no. 2 near 

Lizzie, NC; USGS site number: 353137077332801) and 

downstream site S2 on Plum Tree Branch (USGS station 

name: Unnamed trib to Sandy Run near Lizzie, NC, USGS 

site number: 0209173190) are existing sites used in previous 

investigations and have been in operation since November 

2000 and March 1999, respectively. Collection of water-stage 

data, also referred to as gage-height data, at sites S7, SR5–D1, 

and SR5–T1 began in May 2006 (table 1).

A tipping-bucket rain gage was used at weather station 

site WS2 to record precipitation at 15-minute intervals. 

Calibration checks were conducted semiannually on the rain 

gage to ensure the accuracy of recorded data. Submersible 

pressure transducers were used at sampling sites S7, S2, 

SR5–D1, and SR5–T1 to record water stage at 15-minute 

intervals. Occasionally, a recording interval of 5 minutes 

was used at sites SR5–D1 and SR5–T1 to document rapid 

water-level change during storm events. The installation setup 

for stage recorders and automated samplers is shown for sites 

SR5–D1 and SR5–T1 in figure 3. The culvert at SR5–D1 is 

at the end of a grassed waterway that receives overland runoff 

from a portion of the spray fields. Site SR5–D1 is upstream 

from tile-drain site SR5–T1. Water from sites SR5–D1 and 

SR5–T1 discharges into a receiving ditch that empties into 

Plum Tree Branch between sites S7 and S2 (figs. 2, 3).

At sites S7 and S2, the recorded water-stage data represent stream stage that is reported above an arbitrary datum. 

Stream-stage values of 3.73 feet (ft) and 0.42 ft represent 

stagnant conditions, or the point of zero flow (PZF), at sites 

S7 and S2, respectively. The recorded water-stage data at 

overland-runoff site SR5–D1 and tile-drain site SR5–T1 represent water depth in the plastic corrugated culvert and the PVC 

pipe, respectively. No-flow, or dry, conditions at SR5–D1 and 

SR5–T1 are denoted by water depths equal to zero. Discharge 

measurements at these four sampling sites were determined 

by using a velocity meter or by volumetric methods (Rantz 

and others, 1982). Discrete discharge measurements were 

combined with the continuous water-stage data to develop a 

stage-discharge relation at each sampling location. 

Water-quality sampling was conducted for five stormwater-runoff events from June 2006 to June 2007. For each 

sampling event and site, the automated samplers were programmed to collect up to 24 individual water samples. For an 

individual sample, a sample-bag holder fitted with a clean and 

sterile collection bag was filled with approximately 800 milliliters (mL) of water drawn through a sample intake line. The 

intake line was flushed with native water before each sample 

collection. Samples collected with the automated sampler were 

subdivided such that nutrient analyses were performed on one 

subset of five to six samples and microbiological analyses 

Table 1. Precipitation and stormwater-runoff monitoring locations at the Lizzie Research Site, Greene County, North Carolina, 

2006–2007.

[USGS, U.S. Geological Survey; —, not applicable]

USGS station name Local name USGS site number Type of data collected Data-collection 

interval Period of collection

Weather station no. 2 near

 Lizzie, NC WS2 353137077332801 Precipitation 15 minute 11/29/00 – 09/30/07a

Unnamed trib to Sandy Run at

 SR 1335 near Lizzie, NC S7 0209173150 Water stageWater-quality samples

15 minute

—

05/02/06 – 09/30/07

02/21/06 – 07/18/07

Drainage ditch (SR5D1) to trib 

to Sandy Run near Lizzie SR5–D1 353111077334801 Water stageWater-quality samples

5 or 15 minute

—

05/11/06 – 09/30/07

06/14/06 – 06/04/07

Tile drain (SR5T1) to trib to

 Sandy Run near Lizzie SR5–T1 353111077334901 Water stageWater-quality samples

5 or 15 minute

—

05/11/06 – 09/30/07

02/21/06 – 06/04/07

Unnamed trib to Sandy Run

 near Lizzie, NC S2 0209173190 Water stageWater-quality samples

15 minute

—

03/19/99 – 09/30/07a

02/21/06 – 07/18/07

a

 This period of collection reflects both current and previously collected data.
Data Summary 5

were performed on a second subset of five to six samples. The 

sample subsets consisted of individual samples representing 

rising, peak, and falling stage conditions throughout the event 

hydrograph. In some cases, grab samples were obtained to 

supplement the samples collected with the automated samplers 

during runoff events. In addition to stormwater sampling, grab 

samples for microbiological analyses were collected periodically during base-flow conditions from the monitoring sites. 

Established, documented protocols for collecting and 

processing samples for chemical analyses were followed 

(U.S. Geological Survey, variously dated; U.S. Geological 

Survey, Quality-assurance plan for water-quality activities of 

the North Carolina Water Science Center, written commun., 

2007). Water-quality samples were processed in the field and 

shipped on ice by overnight delivery to the USGS National 

Water Quality Laboratory in Denver, CO, for analysis of 

nutrients or to the EPA analytical laboratory in Cincinnati, 

Ohio, for analysis of microorganisms. Nutrient analyses 

included measurement of dissolved ammonia, total and dissolved ammonia plus organic nitrogen, dissolved nitrite plus 

nitrate, dissolved nitrite, and total and dissolved phosphorus 

according to methods described in Fishman (1993) and Patton 

and Truitt (2000). Microbial analyses included measurement 

of fecal indicator bacteria, including total coliform, E. coli, 

and enterococci using IDEXX analytical methods (IDEXX 

Laboratories, Inc., 2008). Quality-control samples, including 

blanks and replicates, were collected and processed during 

each stormwater-runoff sampling event in order to validate 

results from the environmental samples.

Data Summary

Information on stormwater sampling events, discharge, 

bacteria analyses, and nutrient analyses compiled for the 

Lizzie Research Site during 2006–2007 is summarized 

in this section. Instantaneous loads of nitrate, total coliform, 

E. coli, and enterococci at monitoring sites S7, SR5–D1, 

SR5–T1, and S2 (fig. 2) were computed from discharge and 

concentration data.

Stormwater-Runoff Sampling Events

Water-quality samples for bacteria and nutrient analyses 

were collected for five stormwater-runoff events from June 

2006 to June 2007 (table 2). No automated sampling was 

conducted after June 2007 because of limited stormwater 

Figure 3. Stage recorder and ISCO sampler instrumentation at ditch site SR5–D1 and tile site SR5–T1, Lizzie Research Site, 

Greene County, North Carolina.

Stage recorder

Ditch

outlet

Tile

Stage

recorder

ISCO

samplers

Figure 3. Stage recorder and ISCO sampler instrumentation at ditch site SR5-D1 and tile site SR5-T1, Lizzie Research site,

 Greene County, North Carolina.
6 Microbial and Nutrient Concentration and Load Data During Stormwater Runoff at a Swine CAFO in the Coastal Plain

runoff at the study area during mid- to late-summer 2007. 

Daily precipitation data recorded at the Lizzie Research Site 

rain gage (WS2, fig. 2) are provided in figure 4. 

The number of samples collected for laboratory analysis 

of bacteria and nutrients varied among the sites and events. 

During sampling events 1, 2, and 3, approximately five to 

eight samples per event at upstream site S7 and downstream 

site S2 were analyzed for bacteria and nutrients (table 2). At 

site SR5–D1, flow during events 1 and 3 was minimal; therefore, no samples were collected with the automated sampler. 

At tile site SR5–T1, a cap was placed on the outlet of the tile 

drain during event 2 as part of an experiment to examine the 

effect of reduced tile outflow on water-quality conditions in 

the stream; thus, no automated samples were collected. Tile 

flow during event 3 was insufficient to initiate sampling with 

the automated sampler; however, two grab samples were 

collected for analysis of bacteria and nutrients. Although 

bacteria samples and nutrient samples were collected at each 

site during event 4, the bacteria samples exceeded holdingtime requirements and were not analyzed. For event 5, samples 

only were collected and analyzed for bacteria.

Table 2. Summary of stormwater-runoff event sampling at the Lizzie Research Site, Greene County, North Carolina, 2006–2007.

[#, number; na, not analyzed; —, not sampled]

Stormwaterrunoff 

sampling site

(locations in 

fig. 2)

Event 1

June 14–19, 2006

Event 2

July 23–24, 2006

Event 3

October 17–19, 2006

Event 4

October 27–29, 2006

Event 5a

June 3–4, 2007

# bacteria 

samples

# nutrient 

samples

# bacteria 

samples

# nutrient 

samples

# bacteria 

samples

# nutrient 

samples

# bacteria 

samples

# nutrient 

samples

# bacteria 

samples

# nutrient 

samples

S7 6 6 5 8 7 6 nab 6 6 —

S2 6 6 5 8 7 6 nab 7 7 —

SR5–D1 1c 1c 5 6 —d —d nab 7 2e —

SR5–T1 5f 6 — 1g 2c 2c nab 7 6 —

a

This event only targeted for collection and analysis of bacteria samples.

b

Automated samples were collected but not analyzed because holding times could not be met.

c

Insufficient flow to enable collection with the automated sampler. Grab samples were collected for bacteria and nutrient analyses.

d

Insufficient flow to enable collection with the automated sampler or to obtain grab samples.

e

Sufficient flow but equipment malfunction prevented collection of ISCO samples. Grab samples were collected for bacteria analyses.

f

E. coli bacteria analyzed for all five samples and only four samples were able to be analyzed for enterococci bacteria.

g

The tile drain was capped to prevent outflow during this event; no automated samples were collected. A nutrient grab sample was collected on July 26, 2006, 

when the cap was removed and outflow stabilized.

Figure 4. Daily total precipitation at site WS2 (USGS station number 353137077332801), Lizzie Research Site, 

Greene County, North Carolina.

5.0

4.0

3.0

2.0

1.0

0

TOTAL PRECIPITATION, IN INCHES

Figure 4. Daily total precipitation at site WS2 (USGS station number 353137077332801), Lizzie Research

 site, Greene County, North Carolina.

MAY JUNE JULY AUG.

2006 2007

SEPT. OCT. NOV. DEC. JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEPT.
Data Summary 7

Water Stage and Flow

Daily mean stage, or gage height, data recorded at 

sites S7, S2, SR5–D1, and SR5–T1 from May 2006 through 

September 2007 are provided in figure 5. The storm events 

sampled at each location also are noted on the daily mean 

gage-height plots. Drought conditions observed during the 

study are reflected in the stream-stage data at sites S7 and S2 

where Plum Tree Branch became dry during summer 2007 

(fig. 5A, B). Dry conditions also were observed from June 

to September 2007 at overland runoff site SR5–D1 and tile 

drain site SR5–T1 (fig. 5C, D). Gaps in the data record at 

sites SR5–D1 and SR5–T1 from late December 2006 through 

mid-March 2007 and in May 2007 represent periods when 

the pressure transducers were removed to avoid damage from 

freezing conditions and to perform maintenance. 

The stage data and measured discharge values obtained 

during the study were used to develop a stage-discharge 

relation for each sampling site (rating curve). The rating 

curves were then used to determine discharge for those times 

samples were collected, based on the stage values. Typically, 

it is desirable to make manual measurements of discharge 

over the observed range in stage for computing flow at a site. 

Conditions at the monitoring locations were not conducive 

for making discharge measurements near the highest recorded 

stage values because peak flows during runoff events are 

very flashy and short lived. The rating curves developed for 

sites S7, S2, and SR5–T1 are limited to computing sample 

discharges that do not exceed twice the highest measured 

discharge at each location. The upper limit of use for the rating 

curve at site S7 is 2,693 gallons per minute (gal/min; stage 

of 4.33 ft), site S2 is 22,441 gal/min (stage of 2.52 ft), and 

site SR5–T1 is 74 gal/min (stage of 0.14 ft). The rating curve 

for site SR5–D1 only was used to compute discharges up to 

103 gal/min (stage of 0.23 ft), which represents the highest 

flow during which a water-quality sample was collected for 

laboratory analysis. In addition, sample discharge values 

computed at sites SR5–D1 and SR5–T1 are considered 

estimated on the basis of limited discharge measurements used 

in developing the rating curves and measurement uncertainties 

associated with the recorded stage values. Computed values of 

sample discharge are presented with the analytical results for 

each sample site in the following section.

Microbial and Nutrient Concentrations 

and Loads

The analytical results for the water-quality samples 

collected at stormwater-runoff monitoring site S7 (table 3), 

site S2 (table 4), site SR5–D1 (table 5), and site SR5–T1 

(table 6) are presented in this section. The concentration 

data for total coliforms, E. coli, and enterococci presented 

in this report were provided by EPA (Shane Rogers, written 

commun., November 2007). Many of the bacteria concentrations, especially for total coliform, are reported as a lower or 

upper censored value. The specific censoring levels varied 

among the samples because of differences in sample dilutions 

associated with the laboratory analyses. A compilation of all 

nutrient analytical results, arranged by site, is provided in 

the appendix. The nutrient data also can be accessed online 

from the USGS National Water Information System database 

(U.S. Geological Survey, 2007).

The four monitoring sites provide information on runoff 

pathways from the spray fields through grassed waterways, 

subsurface drainage, and riparian buffers. One interesting 

observation with the runoff data from the Lizzie Research 

Site spray fields is that the nitrite plus nitrate concentrations 

for tile drain site SR5–T1 were higher than overland runoff 

site SR5–D1; conversely, the bacteria concentrations were 

higher at SR5–D1 than at SR5–T1. Concentrations of 

nitrite plus nitrate ranged from 22.2 to 45.4 mg/L at site 

SR5–T1 (table 6) and 1.43 to 13.60 mg/L at site SR5–D1 

(table 5). At site SR5–D1, concentrations of E. coli ranged 

from 86 to 15,988 most probable number per 100 milliliters (MPN/100 mL) and enterococci ranged from 100 to 

770,100 MPN/100 mL. At site SR5–T1, concentrations of 

E. coli ranged from less than 1 to 975 MPN/100 mL and 

enterococci ranged from less than 1 to 1,553 MPN/100 mL.

At each site, the computed sample discharge data and 

the analytical concentration data were used to compute 

instantaneous loads of nitrite plus nitrate, total coliform, 

E. coli, and enterococci (tables 3–6). Note that the values for 

loads reported in tables 3–6 have been rounded to reflect the 

significant figures used in the calculations. For nitrite plus 

nitrate concentrations presented in this report, nitrite typically 

represents a small fraction, less than a few percent, of the 

total nitrite plus nitrate concentration. The computed values 

of instantaneous load are reported in grams per minute for 

nitrite plus nitrate and most probable number per minute for 

total coliform, E. coli, and enterococci. In cases where loads 

were computed using censored results for total coliform, 

E. coli, and enterococci, the stated censoring value was used 

as the concentration, and the resultant load was qualified as 

censored. 

For comparison between sites and events, the computed 

loads for nitrite plus nitrate, E. coli, and enterococci are 

plotted for each monitoring site for the five runoff events 

(figs. 6–10). Censored results for E. coli and enterococci 

included in the plots are denoted as open symbols. Total 

coliform data were not plotted because of the numerous 

censored values associated with these results (tables 3–6). In 

general, instantaneous loads of nitrite plus nitrate, E. coli, and 

enterococci increased from upstream site S7 to downstream 

site S2 on Plum Tree Branch. Additional data are needed to 

further document and evaluate microbial transport from the 

spray fields during stormwater runoff.
8 Microbial and Nutrient Concentration and Load Data During Stormwater Runoff at a Swine CAFO in the Coastal Plain

Figure 5. Daily mean gage heights at sites S7, S2, SR5–D1, and SR5–T1 at the Lizzie Research Site, Greene 

County, North Carolina.

Point of

zero flow

Event 1 Event 2 Event 3

Event 4

Event 5

5.5

5.0

4.5

4.0

3.5

DAILY MEAN GAGE HEIGHT, IN FEET

Point of

zero flow

Event 1

Event 2

Event 3

Event 4

Event 5

2.5

2.0

1.5

1.0

0.5

0

DAILY MEAN GAGE HEIGHT, IN FEET

Gaps in record

Event 1 Event 2

Event 4

Event 5

3.0

2.5

2.0

1.5

1.0

0.5

0

-0.5

DAILY MEAN GAGE HEIGHT, IN FEET

Gaps in record

0.20

0.15

0.10

0.05

0

-0.05

DAILY MEAN GAGE HEIGHT, IN FEET

Figure 5. Daily mean gage heights at sites (A) S7, (B) S2, (C) SR5-D1, and (D) SR5-T1, Lizzie Research

 Site, Greene County, North Carolina.

Event 3

MAY JUNE JULY AUG.

2006 2007

SEPT. OCT. NOV. DEC. JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEPT.

Event 1

Event 4

Event 5

A. S7 (USGS station number 0209173150)

B. S2 (USGS station number 0209173190)

C. SR5-D1 (USGS station number 353111077334801)

D. SR5-T1 (USGS station number 353111077334901)
Data Summary 

9

Table 3. Concentrations and loads for site S7, Greene County, North Carolina, 2006–2007. — Continued[gal/min, gallons per minute; mg/L, milligrams per liter; N, nitrogen; g/min, grams per minute; MPN/100 mL, most probable number per 100 milliliters; MPN/min, most probable number per minute; —, not available or not analyzed; nd, not determined (flow exceeded upper limit of discharge rating curve); <, less than; >, greater than]

Sample

date and time

Discharge 

(gal/min)

Nitrite + 

nitrate

(mg/L as N)

Nitrite + 

nitrate load

(g/min as N)

Total coliform 

(MPN/100 mL)

Total coliform load 

(MPN/minute)

E. coli

(MPN/100 mL)

E. coli load 

(MPN/minute)

Enterococci 

(MPN/100 mL)

Enterococci load 

(MPN/minute)

2/21/06 15:40 — — — 671 — 1 — 1 —3/15/06 15:05 — — — 913 — 1 — 1 —3/28/06 09:00 — — — 500 — 1 — 11 —5/3/06 14:40 4.94 — — 4,410 823,600 9 1,680 193 36,0005/8/06 13:45 339 — — 8,164 104,600,000 148 1,900,000 462 5,920,0006/14/06 11:47 323 2.03 2.48 — — — — — —6/14/06 12:17 840 — — >241,960 >7,682,700,000 11,370 361,000,000 48,840 1,551,000,0006/14/06 12:47 1,300 1.54 7.57 — — — — — —6/14/06 13:17 1,440 — — >241,960 >13,170,000,000 >241,960 >13,170,000,000 64,880 3,531,500,0006/14/06 15:17 nd 1.68 — — — — — — —6/14/06 16:17 nd — — 155,310 — 3,730 — 43,520 —6/14/06 19:17 670 5.19 13.1 — — — — — —6/14/06 21:17 580 — — 198,630 4,354,800,000 3,410 74,761,000 2,880 63,100,0006/15/06 11:17 234 — — 14,560 128,790,000 165 1,460,000 122 1,080,0006/15/06 13:17 211 7.50 5.98 — — — — — —6/19/06 12:25 49.4 7.14 1.33 396 740,000 <1 <1,870 24 44,8007/23/06 17:59 251 4.66 4.42 98,040 930,180,000 <100 <949,000 1,210 11,500,0007/23/06 18:29 2,650 1.59 15.9 — — — — — —7/23/06 18:59 2,650 — — >241,960 >24,237,000,000 980 98,200,000 11,960 1,198,000,0007/23/06 19:29 1,440 1.70 9.25 — — — — — —7/23/06 19:59 780 — — >241,960 >7,134,000,000 200 5,900,000 12,670 373,600,0007/23/06 20:29 580 2.08 4.56 — — — — — —7/24/06 01:29 108 3.40 1.39 — — — — — —7/24/06 03:29 82.1 — — 4,350 13,500,000 88 273,000 6,250 19,400,0007/24/06 17:15 18.0 5.92 0.40 630 429,000 2 1,400 378 257,0007/25/06 10:45 144 1.85 1.01 — — — — — —7/26/06 14:25 26.9 5.22 0.53 — — — — — —8/15/06 15:55 13.9 — — 1,239 651,000 1 525 41 21,50010/17/06 14:45 4.49 — — 7,330 1,244,000 15 2,550 663 113,00010/17/06 23:44 40.4 2.05 0.31 — — — — — —
10 Microbial and Nutrient Concentration and Load Data During Stormwater Runoff at a Swine CAFO in the Coastal Plain Table 3. Concentrations and loads for site S7, Greene County, North Carolina, 2006–2007. — Continued [gal/min, gallons per minute; mg/L, milligrams per liter; N, nitrogen; g/min, grams per minute; MPN/100 mL, most probable number per 100 milliliters; MPN/min, most probable number per minute; —, not available or not analyzed; nd, not determined (flow exceeded upper limit of discharge rating curve); <, less than; >, greater than] Sample date and time Discharge (gal/min) Nitrite + nitrate (mg/L as N) Nitrite + nitrate load (g/min as N) Total coliform (MPN/100 mL) Total coliform load (MPN/minute) E. coli (MPN/100 mL) E. coli load (MPN/minute) Enterococci (MPN/100 mL) Enterococci load (MPN/minute) 10/17/06 23:59 65.5

—

— >241,960 >599,070,000 19,890 49,250,000 81,640 202,100,000

10/18/06 00:44 162 2.04 1.25

—

—

—

—

—

—

10/18/06 00:59 209

—

— >241,960 >1,911,500,000 2,470 19,500,000 57,940 457,700,000

10/18/06 02:44 490

—

— 173,290 3,209,700,000 3,730 69,100,000 22,820 422,700,000

10/18/06 03:14 630 1.15 2.74

—

—

—

—

—

—

10/18/06 05:14 205 2.43 1.88

—

—

—

—

—

—

10/18/06 06:14 241

—

— >241,960 >2,204,200,000 13,960 127,200,000 104,620 953,100,000

10/18/06 12:45 130 9.19 4.52 >241,960 >1,189,000,000 6,970 34,300,000 81,640 401,200,00010/19/06 12:55 89.8 9.63 3.27 >24,196 >82,132,000 1,400 4,750,000 823 2,800,00010/28/06 01:13 2,420 1.66 15.2

—

—

—

—

—

—

10/28/06 01:28 nd 1.37

—

—

—

—

—

—

—

10/28/06 02:43 nd 1.31

—

—

—

—

—

—

—

10/28/06 03:13 nd 1.33

—

—

—

—

—

—

—

10/28/06 12:43 670 4.99 12.6

—

—

—

—

—

—

10/29/06 08:30 269 6.25 6.36

—

—

—

—

—

—

3/14/07 13:20 6.28

—

— 406 96,500 <1 <240 84 19,900

4/3/07 10:35 7.18

—

— 1,844 500,600 21 5,700 2,184 592,700

4/12/07 12:05 66.4

—

— 41,058 103,050,000 1,335 3,351,000 4,959 12,450,000

4/25/07 12:30 4.49

—

— 1,407 238,800 <1 <170 1,013 171,900

5/14/07 09:40 4.49

—

— 2,080 353,000 <1 <170 6,131 1,041,000

5/30/07 09:40 0.90

—

— 12,033 409,400 411 14,000 107 3,640

6/3/07 11:25 82.6

—

— 173,289 541,060,000 1,066 3,328,000 2,937 9,170,000

6/3/07 22:19 164

—

— 46,111 285,850,000 451 2,800,000 180 1,120,000

6/3/07 22:34 425

—

— >241,960 >3,887,100,000 173,289 2,783,900,000 86,644 1,391,900,000

6/4/07 00:04 252

—

— >241,960 >2,304,800,000 81,641 777,680,000 30,759 293,000,000

6/4/07 06:04 83.9

—

— 19,349 61,364,000 316 1,000,000 635 2,010,000

6/4/07 12:15 29.2

—

— 745 822,000 5 5,740 341 376,000

7/18/07 11:20

—

—

—

—

— 2,909

— 12,033

—
Data Summary 11

Table 4. Concentrations and loads for site S2, Greene County, North Carolina, 2006–2007. — Continued[gal/min, gallons per minute; mg/L, milligrams per liter; N, nitrogen; g/min, grams per minute; MPN/100 mL, most probable number per 100 milliliters; MPN/min, most probable number per minute; —, not available or not analyzed; nd, not determined (flow exceeded upper limit of discharge rating curve); <, less than; >, greater than]

Sample

date and time

Discharge 

(gal/min)

Nitrite + 

nitrate

(mg/L as N)

Nitrite + 

nitrate load

(g/min as N)

Total coliform 

(MPN/100 mL)

Total coliform load 

(MPN/minute)

E. coli

(MPN/100 mL)

E. coli load 

(MPN/minute)

Enterococci 

(MPN/100 mL)

Enterococci load 

(MPN/minute)

2/21/06 14:35 18.0 — — 702 478,000 — — 4 2,8003/15/06 15:30 — — — 1,935 — 199 — 20 —3/28/06 11:30 8.98 — — 1,291 438,200 3 1,050 6 2,1405/3/06 15:35 13.5 — — 6,309 3,220,000 41 20,900 784 400,0005/8/06 14:55 443 — — 14,136 236,710,000 439 7,350,000 1,392 23,320,0006/14/06 11:33 274 5.61 5.81 — — — — — —

6/14/06 12:03 570 — — 92,080 1,984,000,000 980 21,100,000 6,290 135,500,0006/14/06 12:33 1,480 2.53 14.2 — — — — — —

6/14/06 13:03 2,510 — — >241,960 >22,957,000,000 3,840 364,300,000 111,990 10,626,000,000

6/14/06 15:03 3,230 2.04 24.9 — — — — — —6/14/06 16:03 3,290 — — >241,960 >30,091,000,000 6,630 824,500,000 61,310 7,625,000,000

6/14/06 18:03 1,970 — — 129,970 9,678,300,000 18,420 1,372,000,000 47,860 3,564,000,0006/14/06 19:03 1,620 4.02 24.6 — — — — — —6/15/06 05:03 490 7.30 13.5 — — — — — —6/15/06 07:03 440 — — 13,540 225,200,000 1,785 29,690,000 805 13,400,000

6/19/06 14:00 26.9 8.75 0.89 17,329 17,620,000 255 259,000 152 154,0007/23/06 18:12 314 10.70 12.7 38,110 452,300,000 225 2,670,000 520 6,170,0007/23/06 18:27 1,210 7.26 33.2 — — — — — —

7/23/06 18:42 2,420 2.40 22.0 — — — — — —7/23/06 18:57 2,540 — — >241,960 >23,231,000,000 6,500 624,100,000 120,330 11,553,000,0007/23/06 19:42 1,710 2.17 14.0 — — — — — —

7/23/06 20:12 1,340 — — >241,960 >12,256,000,000 600 30,400,000 >241,960 >12,256,000,0007/23/06 21:42 540 3.07 6.27 — — — — — —7/24/06 00:12 230 — — 198,630 1,726,900,000 100 869,000 98,040 852,400,000

7/24/06 17:40 26.9 7.92 0.81 77,010 78,300,000 357 363,000 9,590 9,750,0007/25/06 11:55 328 3.49 4.33 — — — — — —7/26/06 15:25 44.9 9.21 1.56 — — — — — —8/15/06 16:25 18.0 — — >24,196 >16,463,000 80 54,700 4,352 2,961,000

10/17/06 15:20 14.8 — — 10,860 6,076,000 105 58,700 2,010 1,124,00010/18/06 00:29 58.4 10.6 2.34 — — — — — —
12 Microbial and Nutrient Concentration and Load Data During Stormwater Runoff at a Swine CAFO in the Coastal Plain Table 4. Concentrations and loads for site S2, Greene County, North Carolina, 2006–2007. — Continued [gal/min, gallons per minute; mg/L, milligrams per liter; N, nitrogen; g/min, grams per minute; MPN/100 mL, most probable number per 100 milliliters; MPN/min, most probable number per minute; —, not available or not analyzed; nd, not determined (flow exceeded upper limit of discharge rating curve); <, less than; >, greater than] Sample date and time Discharge (gal/min) Nitrite + nitrate (mg/L as N) Nitrite + nitrate load (g/min as N) Total coliform (MPN/100 mL) Total coliform load (MPN/minute) E. coli (MPN/100 mL) E. coli load (MPN/minute) Enterococci (MPN/100 mL) Enterococci load (MPN/minute) 10/18/06 00:44 79.4

—

— 37,250 111,800,000 750 2,250,000 4,570 13,700,000

10/18/06 02:29 382 7.56 10.9

—

—

—

—

—

—

10/18/06 02:59 660

—

— 198,630 4,955,400,000 2,685 66,980,000 92,080 2,297,000,000

10/18/06 03:29 990 5.70 21.3

—

—

—

—

—

—

10/18/06 03:59 900

—

— >241,960 >8,231,500,000 7,980 271,500,000 41,060 1,397,000,000

10/18/06 04:59 720 2.51 6.83

—

—

—

—

—

—

10/18/06 05:59 540

—

— >241,960 >4,938,900,000 7,940 162,100,000 72,700 1,484,000,000

10/18/06 11:45 251 6.56 6.22 >241,960 >2,295,700,000 15,530 147,300,000 77,010 730,700,00010/19/06 14:15 103 9.59 3.73 >24,196 >94,205,000 1,150 4,480,000 1,297 5,050,00010/27/06 22:40 408 6.73 10.4

—

—

—

—

—

—

10/27/06 23:09 900 5.36 18.2

—

—

—

—

—

—

10/28/06 01:09 1,570 2.98 17.7

—

—

—

—

—

—

10/28/06 03:09 3,370 2.57 32.7

—

—

—

—

—

—

10/28/06 08:09 1,350 4.42 22.6

—

—

—

—

—

—

10/28/06 17:10 630 6.68 15.9

—

—

—

—

—

—

10/29/06 10:15 346 7.92 10.4

—

—

—

—

—

—

3/14/07 13:45 35.9

—

— 1,405 1,907,000 1 1,360 56 76,500

4/3/07 11:10 22.4

—

— 5,475 4,636,000 12 10,500 198 168,000

4/12/07 12:45 238

—

— 54,750 492,600,000 2,924 26,300,000 11,685 105,120,000

4/25/07 14:00 44.9

—

— 2,480 4,210,000 2 3,390 198 337,000

5/14/07 11:20 16.6

—

— 6,131 3,847,000 18 11,400 607 381,000

5/30/07 10:30 0.0

—

— 15,531 0 94 0 204 0

6/3/07 12:05 71.8

—

— >241,960 >656,690,000 6,314 17,140,000 29,866 81,058,000

6/3/07 22:53 254

—

— 198,629 1,907,100,000 1,711 16,430,000 2,500 24,000,000

6/3/07 23:08 414

—

— >241,960 >3,786,500,000 5,633 88,150,000 10,144 158,750,000

6/3/07 23:38 520

—

— >241,960 >4,756,000,000 5,731 112,600,000 9,590 188,500,000

6/4/07 00:38 406

—

— >241,960 >3,713,300,000 46,111 707,660,000 19,179 294,340,000

6/4/07 02:38 226

—

— >241,960 >2,067,000,000 43,517 371,760,000 14,012 119,700,000

6/4/07 10:00 53.9

—

— 173,289 353,060,000 3,103 6,322,000 4,568 9,307,000

7/18/07 12:20 13.5

—

— 365,400 186,460,000 8,664 4,421,000 26,200 13,370,000
Data Summary 13

Table 5. Concentrations and loads for site SR5–D1, Greene County, North Carolina, 2006–2007. [gal/min, gallons per minute; mg/L, milligrams per liter; N, nitrogen; g/min, grams per minute; MPN/100 mL, most probable number per 100 milliliters; MPN/min, most probable number per minute; —, not available or not analyzed; nd, not determined (flow exceeded upper limit of discharge rating curve); <, less than; >, greater than]

Sample

date and time

Discharge 

(gal/min)

Nitrite + 

nitrate

(mg/L as N)

Nitrite + 

nitrate load

(g/min as N)

Total coliform 

(MPN/100 mL)

Total coliform load 

(MPN/minute)

E. coli

(MPN/100 mL)

E. coli load 

(MPN/minute)

Enterococci 

(MPN/100 mL)

Enterococci load 

(MPN/minute)

6/14/06 13:20 0.95 1.95 0.01 538,000 19,300,000 5,380 193,000 67,850 2,437,0007/23/06 18:02 .23 5.42 .01 — — — — — —7/23/06 18:17 21.9 — — >2,419,600 >2,003,000,000 1,808 1,497,000 248,100 205,400,0007/23/06 18:32 15.8 13.60 .81 — — — — — —7/23/06 18:47 49.2 — — 1,986,300 3,694,000,000 15,531 28,884,000 66,300 123,300,0007/23/06 19:02 99.3 9.90 3.72 — — — — — —7/23/06 19:17 80.7 — — >2,419,600 >7,381,000,000 5,736 17,500,000 344,800 1,051,800,0007/23/06 19:32 65.5 7.03 1.74 — — — — — —7/23/06 20:17 33.4 6.68 .84 — — — — — —7/23/06 20:47 21.5 — — 980,400 796,800,000 3,441 2,797,000 214,260 174,130,0007/23/06 22:47 4.8 4.09 .07 — — — — — —7/23/06 23:47 3.2 — — 579,400 70,080,000 1,467 177,400 145,000 17,540,00010/28/06 00:14 4.5 3.04 .05 — — — — — —10/28/06 00:34 27.4 4.11 .43 — — — — — —10/28/06 01:29 48.7 2.26 .42 — — — — — —10/28/06 02:14 86.1 2.28 .74 — — — — — —10/28/06 03:14 68.6 1.49 .39 — — — — — —10/28/06 04:44 34.3 1.43 .19 — — — — — —10/28/06 14:10 .95 1.77 .01 — — — — — —4/12/07 12:20 .31 — — >2,419,600 >28,353,000 14,173 166,100 770,100 9,024,0006/3/07 11:40 .23 — — >24,196,000 >210,360,000 15,988 139,000 259,000 2,252,0006/4/07 08:40 .41 — — 109,894 1,703,000 86 13,340 100 1,550
14 Microbial and Nutrient Concentration and Load Data During Stormwater Runoff at a Swine CAFO in the Coastal Plain

Table 6. Concentrations and loads for site SR5–T1, Greene County, North Carolina, 2006–2007. [gal/min, gallons per minute; mg/L, milligrams per liter; N, nitrogen; g/min, grams per minute; MPN/100 mL, most probable number per 100 milliliters; MPN/min, most probable number per minute; —, not available or not analyzed; nd, not determined (flow exceeded upper limit of discharge rating curve); <, less than; >, greater than]

Sample

date and time

Discharge 

(gal/min)

Nitrite + 

nitrate

(mg/L as N)

Nitrite + 

nitrate load

(g/min as N)

Total coliform 

(MPN/100 mL)

Total coliform load 

(MPN/minute)

E. coli

(MPN/100 mL)

E. coli load 

(MPN/minute)

Enterococci 

(MPN/100 mL)

Enterococci load 

(MPN/minute)

2/21/06 15:30

—

—

— 8 — <1

— <1

—

6/14/06 13:10 4.7 28.2 0.50

—

—

—

—

—

—

6/14/06 13:30 5.6

—

— <100 <21,200 24 5,140 980 208,000

6/14/06 14:10 12.5 29.0 1.37

—

—

—

—

—

—

6/14/06 14:40 36.6 30.1 4.16

—

—

—

—

—

—

6/14/06 15:10 16.9

—

— 51,720 33,040,000 49 31,200 414 264,000

6/15/06 00:40 26.8 34.2 3.46

—

—

—

—

—

—

6/15/06 03:40 26.8

—

— 210 213,000 7 7,500 39 39,300

6/15/06 09:40 19.1

—

— 410 296,000 9 6,140

—

—

6/15/06 12:40 7.7 36.6 1.07

—

—

—

—

—

—

6/19/06 13:00 2.61 45.4 .45 232 22,900 4 395 <1 <997/26/06 14:55 5.6 34.3 .73

—

—

—

—

—

—

8/15/06 15:45 2.3

—

— 52 4,520 2 174 19 1,600

10/18/06 10:15 1.63 29.8 .18 57,940 3,570,000 975 60,100 850 52,40010/19/06 13:40 .27 37.4 .04 9,804 100,100 37 378 84 85910/27/06 22:46 4.8 33.8 .61

—

—

—

—

—

—

10/27/06 23:16 14.7 28.3 1.57

—

—

—

—

—

—

10/28/06 01:31 35.6 22.9 3.08

—

—

—

—

—

—

10/28/06 03:31 60.8 22.2 5.10

—

—

—

—

—

—

10/28/06 06:31 47.6 23.3 4.19

—

—

—

—

—

—

10/28/06 16:30 11.4 28.1 1.21

—

—

—

—

—

—

10/29/06 09:15 18.0 31.2 2.12

—

—

—

—

—

—

3/14/07 13:25 .41

—

— 15 233 <1 <15 101 1,560

4/12/07 12:20 7.1

—

— 2,785 747,400 345 92,500 1,553 416,800

4/25/07 13:05 1.9

—

— 214 15,400 1 72 4 290

5/14/07 10:00 na

—

— 39

— <1

— 2 —

6/3/07 11:40 1.9

—

— 29,093 2,089,500 55 3,940 31 2,200

6/3/07 22:42 5.6

—

— 2,334 494,100 17 3,660 365 77,300

6/3/07 23:12 6.5

—

— 86,644 21,288,000 162 39,700

—

—

6/4/07 00:57 7.4

—

— 3,361 940,100 579 162,000 727 203,000

6/4/07 04:27 6.3

—

— 1,869 445,100 228 54,300 74 17,700

6/4/07 10:55 4.5

—

— <100 <17,000 22 3,670 6 1,100
Data Summary 15

Figure 6. Instantaneous loads of nitrite plus nitrate, Eschericia coli, and enterococci for sampling event 1, June 14–19, 

2006, Lizzie Research Site, Greene County, North Carolina.

30

25

20

15

10

5

0

NITRITE PLUS NITRATE

(GRAMS PER MINUTE AS NITROGEN)

Escherichia coli

(MOST PROBABLE NUMBER

PER MINUTE)

ENTEROCOCCI

(MOST PROBABLE NUMBER PER MINUTE) 1011

1010

109

108

107

106

105

104

103

102

101

1011

1010

109

108

107

106

105

104

103

102

00:00 12:00

14 15

24:00 12:00 24:00 12:00

16 17

24:00 12:00

JUNE

24:00 12:00

18 19

24:00 12:00 24:00

A.

B.

C.

S7

S2

SR5-T1

SR5-D1

Note: open symbol

 denotes results that

 are less than (<) or

 greater than (>)

 value shown

EXPLANATION

Figure 6. Instantaneous loads of (A) nitrite plus nitrate, (B) Escherichia coli, and

 (C) enterococci for sampling event 1, June 14–19, 2006, Lizzie Research site,

 Greene County, North Carolina.

>

<

<
16 Microbial and Nutrient Concentration and Load Data During Stormwater Runoff at a Swine CAFO in the Coastal Plain

Figure 7. Instantaneous loads of nitrite plus nitrate, Eschericia coli, and enterococci for sampling event 2, July 23–24, 

2006, Lizzie Research Site, Greene County, North Carolina.

35

30

25

20

15

10

5

0

12:00

23 24

18:00 24:00 06:00 12:00 18:00 24:00

JULY

A.

B.

C.

Figure 7. Instantaneous loads of (A) nitrite plus nitrate, (B) Escherichia coli, and 

 (C) enterococci for sampling event 2, July 23–24, 2006, Lizzie Research site,

 Greene County, North Carolina.

109

108

107

106

105

104

103

102

109

108

1011

1010

107

106

105

104

103

S7

S2

SR5-D1

EXPLANATION

Note: open symbol

 denotes results that

 are less than (<) or

 greater than (>)

 value shown

NITRITE PLUS NITRATE

(GRAMS PER MINUTE AS NITROGEN)

Escherichia coli

(MOST PROBABLE NUMBER

PER MINUTE)

ENTEROCOCCI

(MOST PROBABLE NUMBER PER MINUTE)

>

<
Data Summary 17

Figure 8. Instantaneous loads of nitrite plus nitrate, Eschericia coli, and enterococci for sampling event 3, 

October 17–19, 2006, Lizzie Research Site, Greene County, North Carolina.

25

20

15

10

5

0

17 18 19

18:00 24:00 06:00 12:00 18:00 24:00 06:00 12:00 18:00

OCTOBER

A.

B.

C.

S7

S2

SR5-T1

EXPLANATION

Figure 8. Instantaneous loads of (A) nitrite plus nitrate, (B) Escherichia coli, and 

 (C) enterococci for sampling event 3, October 17–19, 2006, Lizzie Research site,

 Greene County, North Carolina.

109

108

107

106

105

104

103

102

109

108

102

1010

107

106

105

104

103

NITRITE PLUS NITRATE

(GRAMS PER MINUTE AS NITROGEN)

Escherichia coli

(MOST PROBABLE NUMBER

PER MINUTE)

ENTEROCOCCI

(MOST PROBABLE NUMBER PER MINUTE)
18 Microbial and Nutrient Concentration and Load Data During Stormwater Runoff at a Swine CAFO in the Coastal Plain

Figure 9. Instantaneous loads of nitrite plus nitrate for sampling event 4, October 27–29, 2006, 

Lizzie Research Site, Greene County, North Carolina.

Figure 10. Instantaneous loads of Eschericia coli and enterococci for sampling event 5, June 3–4, 2007, Lizzie 

Research Site, Greene County, North Carolina.

35

30

25

20

15

10

5

0

27 28 29

18:00 24:00 06:00 12:00 18:00 24:00 06:00 12:00 18:00

OCTOBER

S7

S2

SR5-T1

SR5-D1

Figure 9. Instantaneous loads of nitrite plus nitrate, for sampling event 4, 

October 27–29, 2006, Lizzie Research site, Greene County, North Carolina.

NITRITE PLUS NITRATE

(GRAMS PER MINUTE AS NITROGEN)

12:00

3 4

18:00 24:00 06:00 12:00 18:00 24:00

JUNE

A.

B.

S7

S2

SR5-D1

SR5-T1

EXPLANATION

Figure 10. Instantaneous loads of (A) Escherichia coli, and (B) enterococci for

 sampling event 5, June 3–4, 2006, Lizzie Research site, Greene County,

 North Carolina.

109

108

107

106

105

104

103

102

109

108

1011

1010

107

106

105

104

103

Escherichia coli

(MOST PROBABLE NUMBER

PER MINUTE)

ENTEROCOCCI

(MOST PROBABLE NUMBER PER MINUTE)
References Cited 19

Acknowledgments

This report is based on work conducted cooperatively 

by the U.S. Environmental Protection Agency’s National 

Risk Management Research Laboratory (EPA NRMRL) in 

Cincinnati, Ohio, and U.S. Geological Survey staff in Raleigh, 

NC. Primary funding for the stormwater-runoff monitoring 

program at the Lizzie Research Site was provided by EPA. 

The author also acknowledges the North Carolina Department 

of Environment and Natural Resources, Division of Water 

Quality (NCDENR DWQ), for their support of research 

activities included as part of this study.

Much appreciation is extended to the private landowners 

who graciously allowed access to their property, especially 

Mr. Everette Murphrey who has provided much assistance 

and support during the many studies conducted for more than 

10 years at the Lizzie Research Site. The author thanks EPA 

NRMRL staff in Cincinnati and NCDENR DWQ staff in 

Raleigh for their help and support. Also, John Walker with the 

EPA NRMRL in Research Triangle Park graciously provided 

ISCO automated samplers for use during the study. Thanks 

also to Scott Caldwell and Gary Garrett of the U.S. Geological 

Survey, North Carolina Water Science Center, for their help 

in collecting and processing hydrologic data for the Lizzie 

Research Site. 

References Cited

Fishman, M.J., ed., 1993, Methods of analysis by the U.S. 

Geological Survey National Water Quality Laboratory—

Determination of inorganic and organic constituents in 

water and fluvial sediments: U.S. Geological Survey OpenFile Report 93–125, 217 p.

Harden, S.L., and Spruill, T.B., 2004, Ionic composition and 

nitrate in drainage water from fields fertilized with different 

nitrogen sources, Middle Swamp Watershed, North Carolina, August 2000–August 2001: U.S. Geological Survey 

Scientific Investigations Report 2004–5123, 14 p.

Harden, S.L., and Spruill, T.B., 2008, Factors affecting nitrate 

delivery to streams from shallow ground water in the North 

Carolina Coastal Plain: U.S. Geological Survey Scientific 

Investigations Report 2008–5021, 39 p.

IDEXX Laboratories, Inc., 2008, Document library for 

colilert-18, US EPA approvals: accessed April 2008 at 

http://www.idexx.com/water/colilert18/moreinfo.jsp#15.

Patton, C.J., and Truitt, E.P., 2000, Methods of analysis by 

the U.S. Geological Survey National Water Quality Laboratory—Determination of ammonium plus organic nitrogen 

by a Kjeldahl digestion method and an automated photometric finish that includes digest cleanup by gas diffusion: 

U.S. Geological Survey Open-File Report 00–170, 31 p.

Rantz, S.E., and others, 1982, Measurements and computation 

of streamflow, volumes 1 and 2: U.S. Geological Survey 

Water-Supply Paper 2175, 631 p.

Spruill, T.B., Tesoriero, A.J., Mew, H.E., Jr., Farrell, K.M., 

Harden, S.L., Colosimo, A.B., and Kramer, S.R., 2005, 

Geochemistry and characteristics of nitrogen transport 

at a confined animal feeding operation in a Coastal Plain 

agricultural watershed, and implications for nutrient loading in the Neuse River Basin, North Carolina, 1999–2002: 

U.S. Geological Survey Scientific Investigations Report 

2004–5283, 57 p.

Tesoriero, A.J., Spruill, T.B., Mew, H.E., Jr., Farrell, K.M., 

and Harden, S.L., 2005, Nitrogen transport and transformation in a coastal plain watershed—Influence of geomorphology on flow paths and residence times: Water Resources 

Research, v. 41, W02008, doi:10.1029/2003WR002953, 

15 p.

U.S. Geological Survey, variously dated, National field manual 

for the collection of water-quality data: U.S. Geological 

Survey Techniques of Water-Resources Investigations, 

book 9, chaps. A1–A9, 2 v., variously paged, [Chapters 

were published from 1997–1999; updates and revisions are 

ongoing and can be viewed at http://water.usgs.gov/owq/

FieldManual/index.html].

U.S. Geological Survey, 2007, USGS water-quality data for 

North Carolina: accessed April 2008 at http://waterdata.

usgs.gov/nc/nwis/qw.

Walker, J., Spence, P., Kimbrough, S., and Robarge, W., 2008, 

Inferential model estimates of ammonia dry deposition in 

the vicinity of a swine production facility: Atmospheric 

Environment, v. 42, no. 14, p. 3407–3418.
20 Microbial and Nutrient Concentration and Load Data During Stormwater Runoff at a Swine CAFO in the Coastal Plain

Appendix. Summary of nutrient analytical results for stormwater event samples collected at the Lizzie Research Site, Greene 

County, North Carolina, 2006–2007. — Continued

[N, nitrogen; mg/L, milligrams per liter; PC, parameter code; P, phosphorus; E, estimated; <, less than; —, not analyzed]

Date Time

Ammonia 

+ organic 

N, water, 

filtered, mg/L 

as N

(PC00623)

Ammonia + 

organic N, 

water, 

unfiltered, 

mg/L as N

(PC00625)

Ammonia, 

water, 

filtered, 

mg/L as N

(PC00608)

Nitrite + 

nitrate, 

water, 

filtered, 

mg/L as N 

(PC00631)

Nitrite, 

water, 

filtered, 

mg/L as N 

(PC00613)

Phosphorus, 

water, 

filtered, 

mg/L as P 

(PC00666)

Phosphorus, 

water, 

unfiltered, 

mg/L as P 

(PC00665)

Site S7

06/14/06 1147 0.73 1.5 0.051 2.03 0.01 0.073 0.35

06/14/06 1247 .98 2.2 .037 1.54 .01 .200 .65

06/14/06 1517 1.10 2.1 .069 1.68 .01 .270 .64

06/14/06 1917 1.70 2 .590 5.19 .01 .094 .21

06/15/06 1317 1.10 1.2 .307 7.50 .01 .018 .08

06/19/06 1225 .41 0.52 .054 7.14 .01 E .003 .04

07/23/06 1759 1.30 1.9 .148 4.66 .02 .042 .40

07/23/06 1829 1.80 3.2 .210 1.59 .02 .420 1.10

07/23/06 1929 2.00 2.2 .234 1.70 .03 .290 .52

07/23/06 2029 1.90 2 .236 2.08 .03 .188 .38

07/24/06 0129 1.20 1.1 .123 3.40 .02 .038 .14

07/24/06 1715 .52 .7 .076 5.92 .01 .014 .07

07/25/06 1045 1.50 1.5 .056 1.85 .01 .090 .25

07/26/06 1425 1.00 0.72 .083 5.22 .01 .011 .06

10/17/06 2344 .97 1.1 .030 2.05 .01 .061 .27

10/18/06 0044 1.10 1.1 .049 2.04 .01 .075 .34

10/18/06 0314 1.50 1.5 .117 1.15 .01 .219 .58

10/18/06 0514 1.30 1.6 .081 2.43 .01 .174 .35

10/18/06 1245 1.10 1.2 .090 9.19 .02 .043 .19

10/19/06 1255 .88 .72 .060 9.63 .01 .016 .07

10/28/06 0113 1.20 1.7 < .020 1.66 .01 .245 .62

10/28/06 0128 1.20 1.6 < .020 1.37 .004 .245 .79

10/28/06 0243 1.10 1.7 < .020 1.31 .01 .330 .72

10/28/06 0313 1.00 1.3 < .020 1.33 .01 .328 .53

10/28/06 1243 1.20 1.2 .025 4.99 .01 .081 .29

10/29/06 0830 .84 .71 .036 6.25 .00 .021 .08

Site S2

06/14/06 1133 2.00 2.6 1.230 5.61 0.07 0.022 0.30

06/14/06 1233 1.40 4 .598 2.53 .03 .124 1.06

06/14/06 1503 1.20 3 .263 2.04 .01 .112 .79

06/14/06 1903 1.50 2.1 .451 4.02 .02 .110 .32

06/15/06 0503 1.50 1.9 .734 7.30 .02 .028 .15

06/19/06 1400 1.70 2 1.290 8.75 .10 .007 .06

07/23/06 1812 4.70 3.7 2.000 10.70 .81 .033 .24

07/23/06 1827 2.60 4.4 1.300 7.26 .61 .044 .84

07/23/06 1842 2.00 7.9 .873 2.40 .09 .036 1.77

07/23/06 1942 1.70 3.2 .235 2.17 .04 .290 1.04
Appendix 21

Appendix. Summary of nutrient analytical results for stormwater event samples collected at the Lizzie Research Site, Greene 

County, North Carolina, 2006–2007. — Continued

[N, nitrogen; mg/L, milligrams per liter; PC, parameter code; P, phosphorus; E, estimated; <, less than; —, not analyzed]

Date Time

Ammonia 

+ organic 

N, water, 

filtered, mg/L 

as N

(PC00623)

Ammonia + 

organic N, 

water, 

unfiltered, 

mg/L as N

(PC00625)

Ammonia, 

water, 

filtered, 

mg/L as N

(PC00608)

Nitrite + 

nitrate, 

water, 

filtered, 

mg/L as N 

(PC00631)

Nitrite, 

water, 

filtered, 

mg/L as N 

(PC00613)

Phosphorus, 

water, 

filtered, 

mg/L as P 

(PC00666)

Phosphorus, 

water, 

unfiltered, 

mg/L as P 

(PC00665)

Site S2 (Continued)

07/23/06 2142 2.10 2.1 0.328 3.07 0.06 0.260 0.51

07/24/06 1740 2.80 2.4 1.300 7.92 .13 .033 .09

07/25/06 1155 2.20 2.3 .470 3.49 .03 .128 .35

07/26/06 1525 2.40 2.1 1.410 9.21 .14 .019 .06

10/18/06 0029 3.50 3.5 2.380 10.60 .32 .023 .13

10/18/06 0229 2.80 2.8 1.510 7.56 .19 .084 .21

10/18/06 0329 3.10 3.4 1.800 5.70 .10 .067 .37

10/18/06 0459 1.30 1.6 .269 2.51 .03 .112 .35

10/18/06 1145 1.40 1.6 .435 6.56 .05 .065 .19

10/19/06 1415 1.60 1.5 .792 9.59 .12 .017 .06

10/27/06 2240 2.60 3 1.780 6.73 .15 .021 .14

10/27/06 2309 2.50 2.4 1.180 5.36 .07 .094 .31

10/28/06 0109 1.60 2 .284 2.98 .02 .208 .59

10/28/06 0309 1.20 2.6 .093 2.57 .02 .288 .97

10/28/06 0809 1.20 1.6 .147 4.42 .01 .157 .40

10/28/06 1710 1.60 1.3 .221 6.68 .02 .048 .19

10/29/06 1015 1.20 1 .494 7.92 .02 .018 .08

Site SR5–D1

06/14/06 1320 4.20 5.2 0.084 1.95 0.03 1.670 1.91

07/23/06 1802 4.80 7.1 1.040 5.42 .04 3.740 4.25

07/23/06 1832 6.90 8 1.060 13.60 .10 3.950 4.11

07/23/06 1902 6.50 7 1.040 9.90 .12 3.870 4.23

07/23/06 1932 5.10 6.1 .694 7.03 .22 3.280 3.34

07/23/06 2017 4.90 5.8 .529 6.68 .43 3.030 3.51

07/23/06 2247 4.80 5.4 .412 4.09 .18 3.270 3.60

10/28/06 0014 3.90 4.5 .098 3.04 .02 1.970 2.81

10/28/06 0034 3.90 4.5 .163 4.11 .04 2.520 3.04

10/28/06 0129 2.80 2.5 .091 2.26 .02 1.690 2.12

10/28/06 0214 2.40 2.3 .054 2.28 .03 1.710 1.97

10/28/06 0314 2.00 2.1 E .017 1.49 .02 1.580 1.69

10/28/06 0444 2.20 2.5 .021 1.43 .01 1.710 1.79

10/28/06 1410 3.00 2.7 .041 1.77 .01 1.810 2.21

Site SR5–T1

06/14/06 1310 0.83 — 0.280 28.20 — 0.022 —

06/14/06 1410 .77 — .257 29.00 — .019 —

06/14/06 1440 .66 — .104 30.10 — .033 —

06/15/06 0040 .48 — .014 34.20 — .013 —
22 Microbial and Nutrient Concentration and Load Data During Stormwater Runoff at a Swine CAFO in the Coastal Plain

Appendix. Summary of nutrient analytical results for stormwater event samples collected at the Lizzie Research Site, Greene 

County, North Carolina, 2006–2007. — Continued

[N, nitrogen; mg/L, milligrams per liter; PC, parameter code; P, phosphorus; E, estimated; <, less than; —, not analyzed]

Date Time

Ammonia 

+ organic 

N, water, 

filtered, mg/L 

as N

(PC00623)

Ammonia + 

organic N, 

water, 

unfiltered, 

mg/L as N

(PC00625)

Ammonia, 

water, 

filtered, 

mg/L as N

(PC00608)

Nitrite + 

nitrate, 

water, 

filtered, 

mg/L as N 

(PC00631)

Nitrite, 

water, 

filtered, 

mg/L as N 

(PC00613)

Phosphorus, 

water, 

filtered, 

mg/L as P 

(PC00666)

Phosphorus, 

water, 

unfiltered, 

mg/L as P 

(PC00665)

Site SR5–T1 (Continued)

06/15/06 1240 0.43 — 0.014 36.60 — 0.009 —

06/19/06 1300 .26 — E .006 45.40 — .008 —

07/26/06 1455 .38 — .012 34.30 — .010 —

10/18/06 1015 .58 — < .020 29.80 — .013 —

10/19/06 1340 .51 — E .016 37.40 — .011 —

10/27/06 2246 1.00 — .030 33.80 — .021 —

10/27/06 2316 .94 — .025 28.30 — .030 —

10/28/06 0131 .89 — E .018 22.90 — .019 —

10/28/06 0331 .90 — .020 22.20 — .017 —

10/28/06 0631 1.10 — .028 23.30 — .015 —

10/28/06 1630 .69 — E .017 28.10 — .008 —

10/29/06 0915 .38 — < .020 31.20 — .007 —
Harden—Microbial and Nutrient Concentration and Load Data During Stormwater Runoff at a Swine CAFO, in the NC Coastal Plain, 2006–07—Open-File Report 2008–1156