U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with U.S. Marine Corps, Quantico, Virginia

Quality of Water and Bottom Material in 

Breckenridge Reservoir, Virginia, September 2008 

through August 2009

Open-File Report 2011–1305
Cover photograph. Breckenridge Reservoir, Quantico, Virginia.
Quality of Water and Bottom Material 

in Breckenridge Reservoir, Virginia, 

September 2008 through August 2009

By R. Russell Lotspeich

Prepared in cooperation with U.S. Marine Corps, Quantico, Virginia

Open-File Report 2011–1305

U.S. Department of the Interior

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

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2012

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reproduce any copyrighted materials contained within this report.

Suggested citation:

Lotspeich, R.R., 2012, Quality of water and bottom material in Breckenridge Reservoir, Virginia, September 2008 

through August 2009: U.S. Geological Survey Open-File Report 2011–1305, 19 p., plus appendixes.
iii

Contents

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

Introduction.....................................................................................................................................................2

Purpose and Scope ..............................................................................................................................2

Description of Study Area ...................................................................................................................4

Historical Streamflow and Climatological Data in the Study Area...............................................4

Sample Collection and Analysis..................................................................................................................5

Water Quality of Reservoir Sites .................................................................................................................8

Physical Properties...............................................................................................................................8

Water Temperature .....................................................................................................................8

Dissolved Oxygen.........................................................................................................................9

Specific Conductance.................................................................................................................9

pH..................................................................................................................................................10

Water Clarity...............................................................................................................................10

Chemical Constituents .......................................................................................................................11

Nutrients......................................................................................................................................11

Organic Carbon ..........................................................................................................................12

Major Ions...................................................................................................................................12

Alkalinity......................................................................................................................................14

Silica.............................................................................................................................................14

Pesticides....................................................................................................................................14

Biological Constituents......................................................................................................................14

Trophic Status......................................................................................................................................14

Bottom-Material Quality ....................................................................................................................15

Water Quality of Tributary Sites ................................................................................................................15

Summary........................................................................................................................................................17

Selected References...................................................................................................................................18

Appendixes ...................................................................................................................................................20

Figures

1–2. Maps showing:

1. Location of study area, reference locations, and streamflow and 

 climatological sites near Breckenridge Reservoir, Virginia...........................................3

2. Breckenridge Reservoir, Virginia, watershed, tributary streams, and 

 sampling sites ...........................................................................................................................4

3. Graph showing mean monthly discharge in water year 2009 and minimum, 

maximum, and mean monthly discharges for the period of record at North 

Branch, Middle Branch, and South Branch Chopawamsic Creeks near 

Breckenridge Reservoir, Virginia ...............................................................................................5

4. Map showing location of sampling sites and cross-section profiling points 

in Breckenridge Reservoir, Virginia...........................................................................................6
iv

5–10. Graphs showing depth-averaged seasonal:

5. Water temperature for Breckenridge Reservoir, Virginia, September 2008 

 through August 2009 ...............................................................................................................9

6. Dissolved oxygen for Breckenridge Reservoir, Virginia, September 2008 

 through August 2009 ...............................................................................................................9

7. Specific conductance for Breckenridge Reservoir, Virginia, September 2008

 through August 2009 .............................................................................................................10

8. pH for Breckenridge Reservoir, Virginia, September 2008 

 through August 2009 .............................................................................................................10

9. Turbidity for Breckenridge Reservoir, Virginia, September 2008 

 through August 2009 .............................................................................................................11

10. Graph showing monthly mean E. coli counts, turbidity measurements, and

Secchi-disk depths, and cumulative mean daily discharges in tributary streams 

for sampling periods in Breckenridge Reservoir, Virginia ...................................................15

Tables

1. Physical characteristics of Breckenridge, Lunga, Pea Hill Arm of Lake Gaston, 

Chickahominy, Diascund Creek, and Little Creek Reservoirs, Virginia................................2

2. Watershed land use for Breckenridge Reservoir, Virginia ....................................................5

3. Data collection and reference sites, Breckenridge Reservoir, Virginia, 

September 2008 through August 2009.......................................................................................6

4. Summary of physical properties at 1-foot depth for sampling sites in 

Breckenridge Reservoir and tributaries, Virginia, September 2008 through 

August 2009....................................................................................................................................8

5. Nutrient concentrations at various depths at sampling sites, Breckenridge 

Reservoir, Virginia, December 2008 and August 2009...........................................................12

6. Mean dissolved major-ion concentrations at 1-foot depth at sampling 

sites, in Breckenridge Reservoir, Virginia, during September 2008 through 

August 2009, compared to other reservoirs ...........................................................................13

7. Dissolved major-ion concentrations at various depths at sampling sites, in 

Breckenridge Reservoir, Virginia, December 17, 2008, and August 25, 2009....................13

8. Concentrations of trace elements in bottom-material samples from Breckenridge 

Reservoir, Virginia, July 7, 2009 ................................................................................................16

9. Mean trace-element concentrations in bottom material from Breckenridge 

and Lunga Reservoirs, Virginia.................................................................................................16
v

Conversion Factors

Inch/Pound to SI

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

acre 0.0015625 square mile (m2

)

acre 4,047 square meter (m2

)

acre 0.004047 square kilometer (km2

)

Volume

gallon (gal) 3.785 liter (L)

gallon (gal) 0.003785 cubic meter (m3

)

million gallons (Mgal) 3,785 cubic meter (m3

)

Flow rate

cubic foot per second (ft3

/s) 0.02832 cubic meter per second (m3/s)

million gallons per day (Mgal/d) 0.04381 cubic meter per second (m3

/s)

inch per year (in/yr) 25.4 millimeter per year (mm/yr)

__________________________________________________________________________

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows: 

°C=(°F-32)/1.8.

Horizontal coordinate information (latitude-longitude) is referenced to the North American 

Datum of 1983 (NAD 83).

Vertical elevation information is referenced to North American Vertical Datum of 1988 

(NAVD 88).

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius 

(μS/cm at 25 °C).

Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) 

or micrograms per liter (μg/L). 

Concentrations of chemical constituents in sediment are given either in micrograms per gram 

(μg/g) or micrograms per kilogram (μg/kg).

Water quality, soil-gas, and soil units

L Liter

mg microgram

mg/g microgram per gram

mg/L microgram per liter

mg/kg microgram per kilogram

m/m micrometer

μS/cm microsiemens per centimeter

mg/L milligrams per liter

mL milliliter

mm millimeter
Selected acronyms and abbreviations used in this report:

DEQ Virginia Department of Environmental Quality

DOC dissolved organic carbon

FNU formazin nephelometric units

> greater than

< less than

L liter

MRL minimum reporting level

NOAA National Oceanic and Atmospheric Administration

NWIS National Water Information System

NWQL National Water Quality Laboratory

N normality

ppb parts per billion

SWCB Virginia State Water Control Board

TSI trophic state index

TSIP trophic state index based on total phosphorus concentrations

TOC total organic carbon

USGS U.S. Geological Survey

USMC U.S. Marine Corps

vi
Quality of Water and Bottom Material 

in Breckenridge Reservoir, Virginia, 

September 2008 through August 2009

By R. Russel Lotspeich

Abstract

Breckenridge Reservoir is located within the U.S. Marine 

Corps Base in Quantico, which is in the Potomac River 

basin and the Piedmont Physiographic Province of northern 

Virginia. Because it serves as the principal water supply for 

the U.S. Marine Corps Base in Quantico, an assessment of the 

water-quality of Breckenridge Reservoir was initiated.

Water samples were collected and physical properties 

were measured by the U.S. Geological Survey at three sites 

in Breckenridge Reservoir, and physical properties were 

measured at six additional reservoir sites from September 

2008 through August 2009. Water samples were also collected 

and physical properties were measured in each of the three 

major tributaries to Breckenridge Reservoir: North Branch 

Chopawamsic Creek, Middle Branch Chopawamsic Creek, 

and South Branch Chopawamsic Creek. One site on each 

tributary was sampled at least five times during the study. 

Monthly profiles were conducted for water temperature, 

dissolved-oxygen concentrations, specific conductance, pH, 

and turbidity measured at 2-foot intervals throughout the water 

column of the reservoir. These profiles were conducted at nine 

sites in the reservoir, and data values were measured at these 

sites from the water surface to the bottom of the 

reservoir. These profiles were conducted along three cross 

sections and were used to define the characteristics of the 

entire water column of the reservoir. 

The analytical results of reservoir and tributary samples 

collected and physical properties measured during this study 

were compared to ambient water-quality standards of the 

Virginia Department of Environmental Quality and Virginia 

State Water Control Board. Water temperature, dissolvedoxygen concentration, specific conductance, pH, and turbidity 

measured in Breckenridge Reservoir generally indicated a lack 

of stratification in the water column of the reservoir throughout the study period. This is unlike most other reservoirs in 

the region and may be influenced by the reservoir’s relatively 

short length and the aerators that operate in the reservoir near 

the spillway. In general, the water-quality of Breckenridge 

Reservoir is similar to other reservoirs in the region, and 

the measurements made during this study indicate that the 

reservoir is healthy and is not in violation of published State 

Water Control Board ambient water-quality standards. 

Water samples at three reservoir sites were analyzed for 

53 pesticides, but only atrazine was found to be above the 

laboratory minimum reporting level. Atrazine concentrations 

of 0.008 and 0.010 microgram per liter near the surface and 

bottom of the reservoir, respectively, were found at all three 

sampling locations.

Bottom-material samples were collected for analysis of 

trace elements at all three reservoir sampling sites. Concentrations of arsenic, cadmium, and mercury in bottom material 

were similar to those analyzed in other reservoirs in the 

region. However, most other constituents that were collected 

from Breckenridge Reservoir, especially iron and lead, showed 

much higher concentrations than the other reservoirs. 

During the course of the study, increased turbidity and 

Escherichia coli bacteria counts were observed during or 

after periods of increased tributary discharge, and Secchi-disk 

depths decreased during those same periods. These streamflow 

and water-quality indicators suggest a close relationship 

between Breckenridge Reservoir and its tributaries.
2 Quality of Water and Bottom Material in Breckenridge Reservoir, Virginia, September 2008 through August 2009

Introduction

Water and bottom material samples were collected and 

physical properties were measured by the U.S. Geological 

Survey (USGS) at three sites in Breckenridge Reservoir, and 

physical properties were measured at six additional reservoir 

sites from September 2008 through August 2009. Water 

samples were also collected and physical properties were 

measured in each of the three major tributaries to Breckenridge 

Reservoir: North Branch Chopawamsic Creek, Middle Branch 

Chopawamsic Creek, and South Branch Chopawamsic Creek. 

Analytical results of the reservoir and tributary samples that 

were collected, as well as the physical properties measured 

during this study, were compared to the ambient water-quality 

standards of the Virginia Department of Environmental Quality 

(DEQ) and Virginia State Water Control Board (SWCB).

Breckenridge Reservoir, built in the late 1930s, is the 

principal water-supply source for the U.S. Marine Corps 

(USMC) Base, and also is used for recreational purposes, 

such as fishing, swimming, and canoeing. During periods of 

drought, the water level within Breckenridge Reservoir often 

is sustained by the transfer of water from Lunga Reservoir, 

a much larger reservoir also located on the USMC Base at 

Quantico, Virginia (Va.).

The U.S. Fish and Wildlife Service and the USMC 

Natural Resources and Environmental Affairs Branch 

cooperatively manage Breckenridge and Lunga Reservoirs. 

Because Breckenridge Reservoir is used for public water 

supply and for recreational activities, the USMC asked the 

USGS to evaluate the water quality of Breckenridge Reservoir 

and compare the analytical results of samples collected in the 

reservoir to available DEQ and SWCB ambient water-quality 

standards. In response to this request, the USGS Virginia 

Water Science Center collected and analyzed samples from 

September 2008 through August 2009 for these comparisons.

The SWCB classifies Breckenridge Reservoir as a 

Class III waterway (Commonwealth of Virginia State Water 

Control Board, 2011). The SWCB defines a Class III waterway as a “stream which contains a fair population of wild trout 

with carrying capacity depressed by natural factors or more 

commonly man-related land use practices. Land use activities 

may result in heavy siltation of the stream, destruction of 

banks and fish cover, water quality degradation, increased 

water temperature, etc. Most streams would be considered to 

be in the active state of degradation or recovery from 

degradation. Alteration in land use practices would generally 

improve carrying capacity of the stream” (Commonwealth of 

Virginia State Water Control Board, 2011).

Although the SWCB has established standards for 

dissolved-oxygen concentrations, pH, and water temperature 

for Class III waterways, no other standards currently exist for 

reservoirs in Virginia. The SWCB is developing additional criteria 

for lake and reservoir environments that will address the normal 

seasonal transitions that affect water-quality conditions in these 

lacustrine systems. The data summarized and listed in this report 

can be compared to new standards published in the future.

For water-quality constituents having no SWCB criteria 

available, analytical results of this study were compared with 

information available from previous studies conducted on five 

other manmade reservoirs in the State (table 1; fig. 1). The 

Pea Hill Arm of Lake Gaston, located in the Piedmont 

Physiographic Province, was studied by the USGS between 

1988 and 1990 (Woodside, 1994). Chickahominy, Diascund 

Creek, and Little Creek Reservoirs, located mainly in the 

Coastal Plain Physiographic Province with some of the 

Chickahominy Reservoir watershed located in the Piedmont, 

were studied between 1983 and 1986 (Lynch, 1992). In 

addition, Lunga Reservoir, also located on the USMC Base 

within 5 miles (mi) of Breckenridge Reservoir, was studied 

by the USGS in 2004 and 2005 (Lotspeich, 2007). These 

reservoirs are all much larger than Breckenridge Reservoir 

and serve as water-supply sources for the residents of 

southeastern Virginia.

Table 1. Physical characteristics of Breckenridge, Lunga,

Pea Hill Arm of Lake Gaston, Chickahominy, Diascund Creek,

and Little Creek Reservoirs, Virginia.

[Locations of the reservoirs shown in figure 1; mi2, square miles; ft, feet;

Mgal, million gallons]

Reservoir

Total 

drainage 

area 

(mi2

)

Reservoir 

surface 

area 

(mi2

)

Maximum 

depth 

(ft)

Volume 

(Mgal)

Breckenridge Reservoir 17.4 0.07 38 391

Lunga Reservoir1 10.8 0.66 40 1,700

Pea Hill Arm of Lake 

Gaston2 27.1 2.2 50 8,400

Chickahominy Reservoir3 305 1.70 18 1,900

Diascund Reservoir3 43.6 2.01 24 3,900

Little Creek Reservoir3 4.50 1.48 58 7,480

1From Lotspeich, 2007.

2

From Woodside, 1994.

3From Lynch, 1992.

Purpose and Scope

This report documents the analytical results of waterquality samples and data collected from September 2008 

through August 2009 at nine sites in Breckenridge Reservoir, 

and three tributary streams that feed the reservoir. The 

sampling sites were selected to evaluate the overall quality 

of water within the reservoir and its source water. The waterquality results are compared to available SWCB standards for 

constituents that are considered to affect human and aquatic 

species. No samples were collected during January 2009, 

because the surface of the reservoir was frozen for most of 

the month. The ice was too thick to use a boat and too thin to 

work on safely. The analytical results of sampling for physical, 

chemical, and biological constituents are summarized in the 

following sections.
Introduction 

3

7

MARYLAND

STAFFORD COUNTY

FAQUIER

COUNTY

SPOTSYLVANIA

COUNTY

KING GEORGE

COUNTY

PRINCE WILLIAM

COUNTY

Breckenridge 

Reservoir

7

4

5

6 3

2 1

77°20' 77°30' 77°40'

38°30'38°20'

POTOMAC

RIVER

Lunga 

Reservoir

0 1 2 3 4 5 Miles0 1 2 3 4 5 Kilometers

LINE

Richmond

Fredericksburg

76°0' 77°0' 78°0'

38°0'37°0'

VIRGINIA

MARYLAND

NORTH CAROLINA

FALL

CHESAPEAKE BAY

Potomac

River

Base modified fromU.S. Geological Survey 1:100,000,NAD 83

Base modified fromU.S. Geological Survey 1:100,000,NAD 83

Lunga 

Reservoir

Chickahominy 

Reservoir

Little Creek 

Reservoir

Diascund Creek

Reservoir

Pea Hill Arm 

of Lake Gaston

Valley and 

Ridge

Piedmont

Coastal Plain Blue Ridge

BRECKENRIDGE RESERVOIR 

WATERSHED

Appalachian 

Plateau

0 10 20 30 40 50 Miles

0 10 20 30 40 50 Kilometers

Breckenridge

Reservoir

Breckenridge Reservoir watershedLunga Reservoir watershedUnited States Marine Corps base, Quantico boundaryPrecipitation and air-temperature monitoring site and numberData-collection site and number

EXPLANATION

Fredericksburg

95

17

5

Location of Physiographic Provinces and

Breckenridge Reservoir watershed in Virginia

Figure 1. Locations of the study area, reference locations, and streamflow and climatological sites near Breckenridge Reservoir, Virginia.
4 Quality of Water and Bottom Material in Breckenridge Reservoir, Virginia, September 2008 through August 2009

Description of Study Area

Breckenridge Reservoir is located on the USMC Base at 

Quantico in the Potomac River basin and the Piedmont 

Physiographic Province of northern Virginia (fig. 1). The 

reservoir is impounded by a concrete dam with a spillway 

elevation of approximately 130 feet (ft), as referenced to North 

American Vertical Datum of 1988 (NAVD 88). Two streams 

feed the reservoir: Chopawamsic Creek and South Branch 

Chopawamsic Creek. North Branch and Middle Branch 

converge and form Chopawamsic Creek about 1 mi above the 

reservoir, and South Branch flows farther downstream, and 

enters near the middle of the reservoir (fig. 2).

Breckenridge Reservoir is impounded by a concrete dam, 

has a storage capacity of 391 million gallons (Mgal), covers 

about 45 acres (William Cross, U.S. Marine Corps, Quantico, 

Va., written commun., 2011), and has a maximum depth of 

about 38 ft near the spillway. Water from the reservoir spills 

over the dam and flows downstream for 6 mi where it flows 

into the Potomac River in Stafford County (fig. 1).

The Breckenridge Reservoir watershed has a drainage 

area of 17.4 square miles (mi2; tables 1, 2). The area 

surrounding Breckenridge Reservoir is about 93 percent 

forested and less than (<) 1 percent urbanized (table 2). The 

USMC grants reservoir access to only a small number of 

visitors each year; it also operates multiple rifle shooting 

ranges in the upper part of the watershed. 

Historical Streamflow and Climatological Data 

in the Study Area

Historical streamflow data are available from USGS 

streamgaging stations located on the reservoir tributary 

streams: North Branch Chopawamsic Creek near Independent 

Hill, Va. (01659000), Middle Branch Chopawamsic Creek 

near Garrisonville, Va. (01659500), and South Branch 

Chopawamsic Creek near Garrisonville, Va. (01660000). 

These historical data were compared to streamflow data 

collected during the study period (fig. 3). Streamflow records 

North

Branch

Chopawamsic Creek

Middle

Branch

Chopawamsic

Creek

Chopawamsic Creek

Branch

South

Breckenridge

Reservoir

Lunga

Reservoir

4

5

6

3

2

1

77°30' 77°25'

38°36'

38°34'

38°32'

Base modified from U.S. Geological Survey 1:100,000, NAD 83

Breckenridge Reservoir

watershed

Lunga Reservoir watershed

Data-collection site

and number

EXPLANATION

5

0 1 2 3 KILOMETERS

0 1 2 MILES

Figure 2. Breckenridge Reservoir, watershed, tributary streams, and sampling sites in Virginia.
Sample Collection and Analysis 5

from the gaging stations on the tributary streams indicate 

that flow in the tributary streams was near the mean monthly 

streamflow for the period of record. Likewise, the total amount 

of precipitation measured during the study was also near the 

long-term average. Published National Weather Service precipitation data collected at the Fredericksburg Sewage Treatment 

Plant indicate that a total of 39.5 inches (in.) of precipitation fell 

during the period of study, slightly below the long-term annual 

average of 43 in. (fig. 1, site 7).

Sample Collection and Analysis

Sites were selected and samples were collected through a 

cooperative effort between the USMC and USGS. Water samples 

were collected once a month (except in January) at a depth of 

1.0-ft at sites in the reservoir; sample collection was consistent 

with sampling protocols of the DEQ. Samples also were collected 

from near the bottom of the water column only at reservoir 

sampling sites in December 2008 and August 2009. 

Table 2. Watershed land use around Breckenridge Reservoir, 

Virginia.

[mi2, square miles]

Land-use

classification1

Total area 

(mi2

)

Percentage of 

watershed

Forest 16.2 93.0

Agricultural 0.48 2.75

Wetlands 0.13 0.76

Open water 0.03 0.19

Urban/developed 0.16 0.92

Barren land 0.22 1.28

Grassland 0.19 1.10

Total 17.4 100

1From Goetz and others, 2004.

2008 2009

0.01

0.1

1

10

100

1,000

Discharge, in cubic feet per second

0.01

0.1

1

10

100

1,000

0.01

0.1

1

10

100

1,000

South Branch Chopawamsic Creek (01660000)

North Branch Chopawamsic Creek (01659000)

Middle Branch Chopawamsic Creek (01659500).

2009 mean discharge 

Maximum discharge

Minimum discharge

Mean discharge 

Period of record

EXPLANATION

Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July

Figure 3. Mean monthly 

discharge in water year 2009, 

and maximum, minimum, and 

mean monthly discharges for the 

period of record at North Branch 

Chopawamsic Creek (01659000), 

Middle Branch Chopawamsic 

Creek (01659500), and South 

Branch Chopawamsic Creek 

(01660000) near Breckenridge 

Reservoir, Virginia.
6 Quality of Water and Bottom Material in Breckenridge Reservoir, Virginia, September 2008 through August 2009

Three primary sample-collection sites were selected in 

Breckenridge Reservoir (fig. 1; table 3). One sampling site 

was located at the downstream end of the reservoir just above 

the spillway (fig. 4, site 1). Another sampling site was located 

near the center of the reservoir just below the mouth of South 

Branch Chopawamsic Creek (fig. 4, site 2). The third site was 

located in the upper part of the reservoir above the confluence 

with South Branch Chopawamsic Creek (fig. 4, site 3). These 

three primary sample-collection sites were located near the 

middle of the channel where the reservoir depth was greatest. 

Six additional sites in the reservoir were used as 

cross-section profiling points where physical properties were 

periodically measured (fig. 4). These sites were paired with 

the primary sampling sites to form cross-sections that partially 

traversed the width of the reservoir to document any 

variability in water chemistry across the reservoir. At these 

cross sections, measurements of water temperature, specific 

conductance, pH, dissolved oxygen, and turbidity were made 

from the water surface to the bottom of the reservoir. These 

measurements were taken monthly at 2-ft intervals throughout 

the water column.

To document the characteristics of water flowing into 

the reservoir, water-quality samples were collected at USGS 

streamgaging sites on three tributary streams (fig. 1, sites 4–6). 

These tributary stream sites were generally sampled on a 

quarterly basis in an attempt to capture seasonal variations in 

water-quality conditions.

77°24' 77°23'30"

38°32'45"

38°32'30"

38°32'15"

EXPLANATION

Data-collection site and number

Cross-section profiling point 

Breckenridge

Reservoir 

Base modified from U.S. Geological Survey 1:100,000, NAD 83

0 0.1 0.2 0.3 MILES

0 0.1 0.2 0.3 KILOMETERS

3

2

1

1

Figure 4. Location of sampling sites and cross-section

profiling points in Breckenridge Reservoir, Virginia.

Table 3. Data-collection and reference sites for Breckenridge Reservoir, Virginia, September 2008 through August 2009.

[USGS, U.S. Geological Survey; ft, feet; na, not applicable; NOAA, National Oceanic and Atmospheric Administration. Data type: P, periodic water-quality; 

R, rainfall; D, discharge. Site numbers shown in figure 1]

Site

number

Site name and 

USGS identification number Latitude Longitude

Mean 

depth 

(ft)

Data 

type

Data

source

1 Breckenridge Reservoir above Dam near Joplin (01660030) 38°32’18” 77°23’34” 29.6 P USGS

2 Breckenridge Reservoir below South Branch Chopawamsic Creek 

near Joplin (01660020)

38°32’31” 77°23’45” 23.1 P USGS

3 Breckenridge Reservoir above South Branch Chopawamsic Creek 

near Joplin (01659700)

38°32’46” 77°23’45” 8.3 P USGS

4 North Branch Chopawamsic Creek near Independent Hill 

(01659000)

38°33’54” 77°25’34” na D,P USGS

5 Middle Branch Chopawamsic Creek near Garrisonville (01659500) 38°33’26” 77°25’32” na D,P USGS

6 South Branch Chopawamsic Creek near Garrisonville (01660000) 38°32’22” 77°25’30” na D,P USGS

7 Fredericksburg Sewage (443204) 38°17’ 77°27’ na R NOAA
Sample Collection and Analysis 7

Water for filtered samples was collected in 3-liter (L) 

Teflon® bottles. Before each sampling event, these bottles 

were cleaned according to USGS guidelines (Wilde and 

others, 1999). After initial collection, water to be analyzed for 

dissolved constituents was pumped from the sample bottle 

through clean Teflon® tubing using a peristaltic pump and then 

filtered into bottles through a clean 0.45-μm pore-size capsule 

filter. Filtrate to be analyzed for concentrations of calcium, 

magnesium, potassium, silica, and sodium was bottled in 

clean, acid-rinsed, 250-mL, clear polyethylene bottles and 

preserved with 2 mL of nitric acid. Filtrate to be analyzed 

for concentrations of chloride, fluoride, and sulfate was 

bottled in clean, filtrate-rinsed, 500-mL, clear polyethylene 

bottles. Filtrate to be analyzed for concentrations of ammonia, 

nitrite, nitrite plus nitrate, total dissolved nitrogen, dissolved 

phosphorus, and dissolved orthophosphate was bottled in 

clean, filtrate-rinsed, 125-mL, brown polyethylene bottles. 

Filtrate to be analyzed for dissolved organic carbon (DOC) 

was collected in baked, unrinsed, 125-mL amber glass bottles 

and preserved with 2 mL of 4.5-N sulfuric acid. 

Laboratory analyses were conducted at the USGS 

National Water Quality Laboratory (NWQL) in Denver, 

Colorado. Water samples were chilled and shipped 

overnight to the NWQL for analysis. Periodic qualityassurance samples were collected and analyzed to evaluate 

field and laboratory procedures. Field blanks were sent to 

the NWQL for analysis in December 2008 and August 2009 

to identify potential contamination field collection, sample 

processing, shipping, and laboratory processing.

Replicate samples were sent to the NWQL for analysis in 

December 2008 and in May, July, and August 2009 to evaluate 

laboratory reproducibility of results. Field measurements 

and analytical results were recorded and stored in the USGS 

National Water Information System (NWIS) database.

In December 2008 and August 2009, water samples to 

be analyzed for concentrations of 53 pesticides were collected 

at the three sampling sites in the reservoir at 1-ft below the 

water surface and near the bottom of the water column. These 

reservoir samples were collected and stored in unrinsed, 1-L 

amber glass bottles that had been baked at 450 °C (app. 2). 

Bottom-material samples were collected from the three 

reservoir sampling sites in July 2009 using a dredge-style 

sampler. These samples were sent to the NWQL where they 

were analyzed for concentrations of 12 trace elements—

arsenic, cadmium, chromium, cobalt, copper, iron, lead, 

manganese, mercury, nickel, selenium, and zinc. A second 

bottom-material sample was collected from each reservoir 

sampling location and sent to the Test America Laboratory in 

Colorado for analysis of phosphorus. This additional bottommaterial sampling and analysis was done through a contract 

that was written by the NWQL, and the results of these 

analyses are stored in the USGS NWIS database.

Water temperature, dissolved-oxygen concentration, 

specific conductance, pH, turbidity, and Secchi-disk depths 

were measured monthly at the three primary reservoir samplecollection sites and the six reservoir cross-section profiling 

points (fig. 4). Concentrations of major ions, nutrients, silica, 

organic carbon, alkalinity, and Escherichia coliform (E. coli) 

bacteria were determined from monthly samples collected at 

the three reservoir sampling sites. Concentrations for these 

same constituents were determined for samples that were 

collected from the three tributary streams. Samples from 

the streams were generally collected on a quarterly basis. 

Water samples at the three reservoir sites were collected 

in December 2008 and again in August 2009 for analysis 

of pesticides. In addition, bottom-material samples were 

collected from the three reservoir sites in July 2009 and 

were analyzed for trace-element concentrations. 

Water temperature, dissolved-oxygen concentration, 

specific conductance, pH, and turbidity were measured at all 

reservoir and stream sites using a multiparameter water-quality 

meter. The meter was calibrated according to published 

USGS guidelines before making field measurements 

(Wilde and others, 1999). Alkalinity of a filtered water sample 

was determined by the incremental titration method using 

a digital titrator with 0.16-normality (N) sulfuric acid and a 

calibrated pH meter. Secchi-disk depths were measured by 

lowering a white disk into the water until it was no longer 

visible. Water samples were collected as grab samples by 

lowering the sample bottle about 1 ft below the water surface 

and holding it in place until the bottle filled. Twice during the 

study, December 2008 and August 2009, water samples also 

were collected from near the bottom of the water column at the 

three reservoir sampling sites. These samples were collected 

using weighted Teflon® tubing and a peristaltic pump.

Bacteria and alkalinity sample processing and analyses 

were conducted by the USGS Virginia Water Science Center. 

Samples collected for bacteriological analysis were processed 

onsite within the 6-hour holding time and placed in pre-heated 

incubators for 20 to 24 hours (Myers and Wilde, 2003). 

Prepared E. coli m-TEC medium was poured into sterile petri 

dishes where the 47-millimeter (mm), 0.45 micrometer (μm) 

filters were placed. E. coli colonies were counted following 

the incubation period. 

Whole, unfiltered water samples were analyzed for 

concentrations of total nitrogen, total phosphorus, bacteria, 

and total organic carbon (TOC; app. 1). Total nitrogen and 

total phosphorus samples were collected in clean, 

125-milliliter (mL), clear polyethylene bottles that were rinsed 

with native water three times just prior to sample collection. 

Samples were preserved with 2 mL of 4.5-N sulfuric acid. 

Samples for bacteriological analysis were collected in 

unrinsed 500-mL borosilicate bottles that had been sterilized 

in an autoclave. Samples collected for TOC analysis were 

collected in unrinsed 125-mL amber glass bottles that had 

been baked at 450 degrees Celsius (°C). 
8 Quality of Water and Bottom Material in Breckenridge Reservoir, Virginia, September 2008 through August 2009

 Water Quality of Reservoir Sites

Water-quality samples were collected monthly at three 

sampling sites in Breckenridge Reservoir. Physical properties, 

which included water temperature, dissolved-oxygen, specific 

conductance, pH, turbidity, and Secchi-disk depths, were 

also measured at the three sample-collection sites and at six 

additional sites (fig. 4). Chemical constituents, which included 

nutrients, organic carbon, major-ions, alkalinity, silica, and 

pesticides, were analyzed from water samples taken at the 

three reservoir sampling sites. Samples from the reservoir sites 

were also analyzed for E. coli bacteria. The trophic status of 

the reservoir was also evaluated using data collected during 

the study.

Physical Properties

Measurements of water temperature, dissolved-oxygen 

concentrations, specific conductance, pH, and turbidity 

were made at nine sites that formed three cross-sections in 

Breckenridge Reservoir, and these measurements provide a 

general understanding of the water quality in the reservoir. 

Measurements made throughout the water column at these 

sites did not indicate a vertical variability or stratification that 

typically is observed in lakes and reservoirs in eastern Virginia 

during warm-weather months.

A thermocline is a transition layer between deep and 

shallow water where changes in water chemistry (commonly 

negative) occur with increasing depth. Although no thermocline was observed in Breckenridge Reservoir, a thermocline 

was observed in Lunga Reservoir during the summer and early 

fall between depths of 10 to 20 ft where the water temperature 

dropped nearly 20 °C, dissolved oxygen reached near-zero 

concentration, and specific conductance more than doubled 

near the bottom (Lotspeich, 2007).

Due to the lack of a thermocline and spatial variability 

of the physical properties that were measured throughout 

Breckenridge Reservoir, the following sections include graphs 

(figs. 5–9) showing depth-averaged data. These data points 

are the average measurements of all three reservoir sampling 

sites taken within 5-ft-depth intervals and compiled over each 

season (apps. 3–5). These plots in the graphs are intended to 

illustrate the general change in water chemistry over the year, 

which was consistent throughout the reservoir.

Water Temperature

Water temperature is a measure of the warmth or coldness 

of the water that directly affects many physical, chemical, 

and biological processes. Water temperature measured at 

1.0-ft depth throughout Breckenridge Reservoir ranged from 

3.6 to 27.2 °C (table 4). Water temperature measured at 

2-ft-depth intervals throughout the water column at the nine 

reservoir sites ranged from 3.2 to 27.7 °C (apps. 3–5). 

Table 4. Summary of physical properties at 1-foot depth for sampling sites in Breckenridge Reservoir and tributaries, Virginia, 

September 2008 through August 2009.

[USGS, U.S. Geological Survey; °C, degrees Celsius; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25 °C; units,

standard pH units; FNU, formazin nephelometric units; —, no data]

Site

number

Site name

and 

USGS identification number

Number

of

samples

Water 

temperature 

(

o

C)

Dissolved 

oxygen

(mg/L)

Specific 

conductance 

(μS/cm)

pH (units) Turbidity (FNU)

MinimumMaximum

MinimumMaximumMinimumMaximumMinimumMaximumMinimumMaximum

1 Breckenridge Reservoir above Dam near 

Joplin (01660030)

11 4.7 26.7 4.4 9.3 38 94 6.0 8.6 3.0 10.3

2 Breckenridge Reservoir below South Branch 

Chopawamsic Creek near Joplin (01660020)

11 4.7 27.2 3.9 9.4 37 94 5.9 8.5 1.9 11.4

3 Breckenridge Reservoir above South Branch 

Chopawamsic Creek near Joplin (01659700)

11 3.6 27.2 3.9 9.9 37 93 5.8 8.6 2.0 9.4

4 North Branch Chopawamsic Creek near 

Independent Hill (01659000)

12 2.2 20.0 6.6 13.6 38 98 6.0 7.9 — —

5 Middle Branch Chopawamsic Creek near 

Garrisonville (01659500)

5 2.3 21.0 8.5 10.9 31 42 6.1 7.9 — —

6 South Branch Chopawamsic Creek near 

Garrisonville (01660000)

5 2.6 21.2 7.8 11.3 37 62 5.9 7.8 — —
 Water Quality of Reservoir Sites 9

All water temperatures measured during the study were below 

the maximum ambient water-quality temperature criteria 

(32 °C) for Class III waterways (Commonwealth of Virginia 

State Water Control Board, 2011). 

Lack of a thermal gradient was observed at all nine sites 

in Breckenridge Reservoir during the spring and summer 

months (fig. 5). Throughout the 12-month study period, 

water temperatures at all of the reservoir sites generally were 

constant throughout the water column, with relatively small 

changes of up to 2.9 °C.

Dissolved Oxygen

Dissolved oxygen is a measurement of the available 

oxygen molecules dissolved in water that directly affect the 

ability of aquatic organisms to survive. Dissolved-oxygen 

concentrations also affect numerous chemical reactions. 

During the colder months, the rate of consumption of oxygen 

in a reservoir may decrease due to colder water temperatures 

and because the solubility of oxygen increases as water 

temperature decreases. Dissolved-oxygen concentrations 

measured in Breckenridge Reservoir generally were higher 

during the colder months and lower during warmer months 

and showed little variation with depth (fig. 6).

Dissolved-oxygen concentrations measured at 

1.0-ft depth throughout Breckenridge Reservoir ranged from 

3.9 to 9.9 milligrams per liter (mg/L; table 4). Dissolvedoxygen concentrations measured at 2-ft-depth intervals 

throughout the water column at all nine reservoir sites ranged 

from 2.8 to 11.7 mg/L (apps. 3–5). The Virginia SWCB 

lists the minimum dissolved-oxygen concentration ambient 

water-quality 

standard for Class III waterways as 4.0 mg/L (Commonwealth 

of Virginia State Water Control Board, 2011). Dissolvedoxygen concentrations measured in Breckenridge Reservoir 

during the study were below the SWCB criterion at two 

sampling sites in September 2008. All other measurements of 

dissolved-oxygen at 1.0-ft depth in Breckenridge Reservoir 

were above the 4.0 mg/L criterion.

Specific Conductance

Specific conductance is a measure of how well a solution 

at 25 °C conducts an electrical current. As the amount of 

negatively and positively charged ions increase in an aqueous 

solution, the conductance of an electrical current by the 

solution also increases. Therefore, water with low ability to 

conduct an electrical current has low specific conductance, 

which in turn indicates low ionic concentration and indicates 

generally better water quality. 

Specific conductance measured at 1.0-ft depth throughout 

Breckenridge Reservoir ranged from 37 to 94 microsiemens 

per centimeter (μS/cm) at 25 °C (table 4), which indicates 

a low ionic activity in the waters of the reservoir (Wetzel, 

2001). Specific conductance measured at 2-ft-depth intervals 

throughout the water column at all nine reservoir sites 

indicated that no substantial stratification was present in the 

reservoir throughout the study period (fig. 7; apps. 3–5). The 

highest specific conductance concentrations in the reservoir, 

93 to 99 μS/cm, were measured in June 2009.

Although the SWCB has no criteria for specific 

conductance, the mean specific conductance in Breckenridge 

Reservoir during the study (52 μS/cm) was lower than the 

mean specific conductance in other reservoirs in the State. 

0

5

10

15

20

25

30

Summer

Fall

Winter

Spring

Depth, in feet

Water temperature, in degrees Celsius

Virginia's maximum water temperature criterion (32 °C)

0 5 10 15 20 25 30 35 0 2 4 6 8 10 12

Dissolved oxygen, in milligrams per liter at 25 degrees Celsius Virginia's minimum dissolved oxygen criteria (4.0 mg/L)

0

5

10

15

20

25

30

Summer

Fall

Winter

Spring

Depth, in feet

Figure 5. Depth-averaged seasonal water temperature for 

Breckenridge Reservoir, Virginia, September 2008 through 

August 2009.

Figure 6. Depth-averaged seasonal dissolved oxygen for 

Breckenridge Reservoir, Virginia, September 2008 through 

August 2009.
10 Quality of Water and Bottom Material in Breckenridge Reservoir, Virginia, September 2008 through August 2009

maximum SWCB pH standard during the entire study period. 

By comparison, Lunga Reservoir had pH measurements 

that ranged from 4.8 to 7.6 standard units during 2004 to 

2005 (Lotspeich, 2007). In the Pea Hill Arm of Lake Gaston 

Reservoir, pH values ranged from 6.8 to 8.2 standard units 

from 1988 to 1990 (Woodside, 1994). The Chickahominy, 

Diascund Creek, and Little Creek reservoirs had pH values 

that ranged from 6.0 to 7.0, 6.5 to 7.0, and 6.5 to 7.5 standard 

units, respectively, from 1983 to 1986 (Lynch, 1992).

Water Clarity

Water clarity in Breckenridge Reservoir was assessed 

during the study period by measuring two different 

indicators—turbidity and Secchi-disk depth. Turbidity isa visual 

property of water that is measured optically with an instrument. 

Increased turbidity suggests a reduction in clarity resulting from 

the presence of increased suspended particles (Wetzel, 2001). 

The Secchi-disk depth is a visual measurement of the vertical 

extinction of light in natural waters (Wetzel, 2001). Factors that 

limit the ability to accurately measure Secchi-disk depth include 

the time of day (amount and angle of sunlight), water color, 

physical condition of the Secchi-disk, and the visual acuity of 

the person taking the reading. 

Turbidity measured at 1.0-ft depth throughout 

Breckenridge Reservoir ranged from 1.9 to 11.4 formazin 

nephelometric units (FNU; table 4). Turbidity measured at 

2-ft-depth intervals throughout the water column at the nine 

reservoir sites ranged from 1.6 to <61.7 FNU (fig. 9; apps. 3–5). 

The higher turbidity values were observed near the bottom of 

the water column and were likely the result of particles settling 

near the bottom. No turbidity data were collected in May 2009 

due to a malfunctioning turbidity probe.

By comparison, from 2004 to 2005, a mean specific 

conductance of 68 μS/cm was measured in Lunga Reservoir 

(Lotspeich, 2007), and a mean specific conductance of 

90 μS/cm was measured in the Pea Hill Arm of Lake Gaston 

Reservoir from 1988 to 1990 (Woodside, 1994). In addition, 

mean specific conductance values of 118, 81, and 117 μS/cm 

were measured in the Chickahominy, Diascund Creek, and 

Little Creek Reservoirs , respectively, from 1983 to 1986 

(Lynch, 1992).

pH

pH is a measure of the activity of the hydrogen ion (H+). 

Natural lake waters that have low pH usually are rich in 

dissolved organic material, and high pH waters usually contain 

high concentrations of salts (Wetzel, 2001). According to 

Wetzel (2001), the pH of most open lakes ranges from 6.0 

to 9.0, which is consistent with the pH of other reservoirs in 

Virginia. 

The pH measured at 1.0-ft depth throughout 

Breckenridge Reservoir ranged from 5.8 to 8.6 standard units 

during the year (table 4). The pH measured at 2-ft intervals 

throughout the water column at the nine reservoir sites ranged 

from 5.6 to 8.6 standard units and generally was lowest during 

the late summer, increased through winter, and peaked in 

March, showing little spatial variability (fig. 8; apps. 3–5). 

The SWCB pH criterion for Class III waterways is a range 

of 6.0 to 9.0 standard units (Commonwealth of Virginia State 

Water Control Board, 2011). The pH values measured at 

1.0-ft depth at all sites in Breckenridge Reservoir fell just 

below the minimum SWCB standard in September 2008. The 

pH values measured at all sites in the reservoir were below the 

20 30 40 50 60 70 80

Specific conductance, in microseimens per centimeter at 25 degrees Celsius

0

5

10

15

20

25

30

Summer Fall

Winter

Spring

Depth, in feet

0

5

10

15

20

25

30

4 5 6 7 8 9 10

Depth, in feet

pH, in units

Virginia's minimum pH criterion (6.0 units)

Virginia's maximum pH criterion (9.0 units)

Summer Fall

Winter

Spring

Figure 8. Depth-averaged seasonal pH for Breckenridge 

Reservoir, Virginia, September 2008 through August 2009.

Figure 7. Depth-averaged seasonal specific conductance for 

Breckenridge Reservoir, Virginia, September 2008 through 

August 2009.
 Water Quality of Reservoir Sites 11

Secchi-disk depths measured at the three sampling 

sites in Breckenridge Reservoir ranged from 2.8 to 5.8 ft 

(app. 6). The deepest Secchi-disk depths were recorded in 

February 2009. The shallowest Secchi-disk depths were 

recorded in December 2008 and June 2009 a few days after 

the tributary streams had higher than normal streamflows. The 

decrease in water clarity during these periods suggests that the 

water quality of the reservoir is closely related to the water 

quality of the tributary streams.

Chemical Constituents

Water samples were collected and analyzed for nutrients, 

organic carbon, major ions, alkalinity, silica, and pesticides to 

further evaluate the water quality of Breckenridge Reservoir. 

The following sections include discussions related to the 

analytical results of these water samples and how they 

compare to other reservoirs in the region. 

Nutrients

 Water samples collected from Breckenridge Reservoir 

were analyzed for the species of nitrogen commonly present 

in water— nitrite, nitrate, ammonia, and organic nitrogen 

(app. 7). Dissolved nitrite-nitrogen concentrations in samples 

collected from the reservoir were at or below the laboratory 

minimum reporting level (MRL) of 0.002 mg/L. Dissolved 

nitrite-plus-nitrate nitrogen and dissolved ammonia-nitrogen 

concentrations ranged from less than the MRLs of 0.016 and 

0.01 mg/L, respectively, to 0.043 and 0.08 mg/L, respectively. 

Total nitrogen (the sum of the nitrogen species) concentrations 

ranged from 0.11 to 0.54 mg/L. Nutrient concentrations in 

samples that were collected near the bottom of the reservoir 

were similar to those in samples collected near the surface 

(table 5).

The mean nitrite-plus-nitrate concentration determined 

for samples collected at 1.0-ft depth at all the three reservoir 

sites (0.020 mg/L) was lower than the mean nitrite-plus-nitrate 

concentration determined for samples collected from Lunga 

Reservoir (0.026 mg/L; Lotspeich, 2007). The mean nitriteplus-nitrate concentration determined for samples from the 

Pea Hill Arm of Lake Gaston Reservoir was also higher at 

0.066 mg/L (Woodside, 1994). Water samples collected from 

the Chickahominy, Diascund, and Little Creek Reservoirs all 

had mean nitrite-plus-nitrate nitrogen concentrations that were 

<0.1 mg/L (Lynch, 1992). 

The mean total nitrogen concentration determined 

for water samples collected at 1.0-ft depth of 0.33 mg/L in 

Breckenridge Reservoir, was less than the mean total nitrogen 

concentrations determined for other reservoirs in the region. 

By comparison, the mean total nitrogen concentrations 

determined for Lunga, Chickahominy, Diascund Creek, Little 

Creek, and Pea Hill Arm of Lake Gaston reservoirs were 

0.4, 0.8, 0.7, 0.7, and 0.5 mg/L, respectively (Lynch, 1992; 

Woodside, 1994; Lotspeich, 2007). 

The mean dissolved ammonia-nitrogen concentration 

determined for water samples collected at 1.0-ft depth in 

Breckenridge Reservoir was of 0.04 mg/L. By comparison, 

the Lunga, Pea Hill Arm of Lake Gaston, Chickahominy, 

Diascund Creek, and Little Creek reservoirs had mean 

dissolved ammonia-nitrogen concentrations of 0.04, 0.40, 

0.80, 0.60, and 0.65 mg/L, respectively (Lynch, 1992; 

Woodside, 1994; Lotspeich, 2007). 

Water samples collected from the three Breckenridge 

Reservoir sampling sites were analyzed for total phosphorus, 

dissolved phosphorus, and dissolved orthophosphorus 

concentrations. Total phosphorus concentrations determined 

for samples collected from the reservoir at 1.0-ft depth 

ranged from 0.013 to 0.041 mg/L, whereas concentrations of 

dissolved phosphorus ranged from 0.005 to 0.016 mg/L. 

Dissolved orthophosphorus concentrations in samples 

collected at 1.0-ft depth and near the bottom in Breckenridge 

Reservoir were below the MRL of 0.008 mg/L. The maximum 

total phosphorus concentration from samples collected in 

the reservoir was 0.041 mg/L, slightly above the SWCB 

criteria of 40 micrograms per liter (μg/L), or 0.040 mg/L 

(Commonwealth of Virginia State Water Control Board, 2011). 

The mean total phosphorus concentration in Breckenridge 

Reservoir, 0.022 mg/L, is near the average of the mean 

concentrations determined for the Lunga, Chickahominy, 

Diascund Creek, and Little Creek Reservoirs, which were 

0.016, 0.049, 0.028, and 0.014 mg/L, respectively (Lynch, 

1992; Lotspeich, 2007).

0

5

10

15

20

25

30

Depth, in feet

0 2 4 6

Turbidity, in formazin nephelometric units

8 10 12 14

Summer

Fall

Winter

Spring

Figure 9. Depth-averaged seasonal turbidity for Breckenridge 

Reservoir, Virginia, September 2008 through August 2009.
12 Quality of Water and Bottom Material in Breckenridge Reservoir, Virginia, September 2008 through August 2009

The SWCB lists maximum allowable concentrations of 

chloride, fluoride, and sulfate for public water supply. The 

maximum dissolved chloride concentration in the reservoir 

samples, 4.44 mg/L (4,440 μg/L, app. 8), was below the 

SWCB criterion of 250,000 μg/L (250 mg/L) for chloride 

concentrations in the public water supply, but higher than the 

maximum dissolved chloride concentration of 2.98 mg/L in 

Lunga Reservoir (Lotspeich, 2007). The maximum dissolved 

fluoride concentration in the reservoir samples, 0.09 mg/L 

(90 μg/L, app. 8), was below the SWCB criterion of 

1,100 μg/L (1.1 mg/L) for fluoride concentrations in public 

water supply and slightly lower than the maximum dissolved 

sulfate concentration of 0.10 mg/L in Lunga Reservoir 

(Lotspeich, 2007). The maximum dissolved sulfate 

concentration in the reservoir samples, 4.00 mg/L 

(4,000 μg/L, app. 8), was below the SWCB criterion of 

250,000 μg/L (250 mg/L) for sulfate concentrations in the 

public water supply and lower than the maximum dissolved 

sulfate concentration of 4.54 mg/L in Lunga Reservoir 

(Lotspeich, 2007). 

Although the SWCB has no criteria for the other major 

ions analyzed during this study, mean concentrations of the 

other dissolved major ions in Breckenridge Reservoir samples 

were similar to or less than those determined for the Lunga, 

Chickahominy, Diascund Creek, and Little Creek Reservoirs 

(Lynch, 1992; Lotspeich, 2007; table 7).

Organic Carbon

Concentrations of total organic carbon (TOC) in samples 

collected at 1.0-ft depth in the reservoir ranged from 2.3 to 

9.8 mg/L (app. 7). The mean TOC concentration of 

5.61 mg/L is between the mean TOC concentrations in the 

Pea Hill Arm of Lake Gaston and Chickahominy reservoirs, 

which were 5.2 and 9.5 mg/L, respectively (Lynch, 1992; 

Woodside, 1994), and very similar to the mean TOC 

concentration of 5.82 mg/L in Lunga Reservoir (Lotspeich, 

2007). Concentrations of TOC in the Diascund Creek and 

Little Creek reservoirs were not measured and, as a result 

could not be compared to the results from Breckenridge 

Reservoir samples. 

Concentrations of dissolved organic carbon (DOC) 

determined for samples collected at 1.0-ft depth in 

Breckenridge Reservoir ranged from 2.1 to 9.7 mg/L, with 

a mean concentration of 5.01 mg/L (app. 7). The mean 

DOC concentration from Breckenridge Reservoir samples 

was higher than the mean DOC concentration of 4.38 mg/L 

determined for Lunga Reservoir (Lotspeich, 2007). 

Major Ions

Concentrations of the major cations (calcium, 

magnesium, potassium, and sodium) and major anions 

(chloride, fluoride, and sulfate) in water samples collected 

from Breckenridge Reservoir generally were low, varied 

seasonally, and varied little spatially (app. 8). Concentrations 

of cations and anions in the reservoir samples also did not vary 

when comparing the 1.0-ft depth samples with the near bottom 

samples (table 6). 

Table 5. Nutrient concentrations at various depths at sampling sites in Breckenridge Reservoir, Virginia, December 17, 2008, and 

August 25, 2009.

 [Concentrations in milligrams per liter; E, estimated concentration; ft, feet; <, less than]

Constituent

December 17, 2008 August 25, 2009

Site 01659700 Site 01660020 Site 01660030 Site 01659700 Site 01660020 Site 01660030

Sampled depth (ft) Sampled depth (ft)

1.0 8.0 1.0 23.0 1.0 29.0 1.0 8.0 1.0 22.0 1.0 30.0

Dissolved nitrite-nitrogen 0.001 E 0.001 E 0.002 E 0.002 E 0.002 E 0.002 E <0.002 <0.002 <0.002 <0.002 <0.002 <0.002

Dissolved nitrite-plus-nitrate 0.017 0.018 0.041 0.033 0.043 0.038 <0.016 <0.016 0.011 E 0.010 E 0.014 E 0.010 E

Dissolved ammonia-nitrogen 0.015 E 0.014 E 0.014 E 0.021 0.017 E 0.025 0.026 0.015 E 0.048 0.099 0.064 0.089

Total dissolved nitrogen 0.47 1.39 0.53 0.93 0.31 1.26 0.38 0.34 0.36 0.40 0.37 0.35

Total nitrogen 0.25 0.34 0.35 0.32 0.33 0.36 0.33 0.34 0.34 0.39 0.36 0.42

Dissolved orthophosphorus <0.008 <0.008 <0.008 <0.008 0.004 <0.008 <0.008 <0.008 <0.008 <0.008 <0.008 <0.008

Total dissolved phosphorus 0.013 0.009 0.008 0.009 0.008 0.009 0.010 0.010 0.011 0.011 0.010 0.011

Total phosphorus 0.024 0.033 0.027 0.031 0.028 0.032 0.021 0.025 0.020 0.024 0.021 0.025
 Water Quality of Reservoir Sites 13

Table 6. Mean dissolved major-ion concentrations at 1-foot depth at sampling sites in 

Breckenridge Reservoir, Virginia, during September 2008 through August 2009, compared 

to other reservoirs.

[Concentrations in milligrams per liter; <, less than]

Constituent Breckenridge 

Reservoir

Lunga 

Reservoir1

Chickahominy 

Reservoir2

Diascund 

Creek 

Reservoir2

Little Creek 

Reservoir2

Calcium 2.63 1.68 7.1 10 9.5

Chloride 3.23 2.57 18 6.4 11

Fluoride 0.05 0.08 <0.1 <0.1 <0.1

Magnesium 1.42 1.06 1.9 0.89 1.6

Potassium 1.22 0.90 1.6 1.1 1.7

Sodium 3.27 2.45 12 3.2 6.8

Sulfate 3.26 3.72 9.6 6.6 9.0

1From Lotspeich, 2007.

2From Lynch, 1992.

Table 7. Dissolved major-ion concentrations at various depths at sampling sites in Breckenridge

Reservoir, Virginia, December 17, 2008, and August 25, 2009.

 [Concentrations in milligrams per liter; ft, feet; —, no data]

Constituent

December 17, 2008 August 25, 2009

Site 01659700 Site 01660020 Site 01660030 Site 01659700 Site 01660020 Site 01660030

Sampled depth (ft) Sampled depth (ft)

1.0 8.0 1.0 23.0 1.0 29.0 1.0 8.0 1.0 22.0 1.0 30.0

Alkalinity 9 9 9 — 8 9 15 14 14 15 14 15

Calcium 2.19 2.21 2.24 2.25 2.32 2.32 3.10 3.02 3.08 3.04 3.05 2.98

Chloride 3.34 3.32 3.18 3.20 3.15 3.07 2.97 3.00 2.96 2.97 2.97 2.95

Fluoride 0.04 0.04 0.04 0.04 0.04 0.05 0.07 0.05 0.05 0.05 0.05 0.05

Magnesium 1.31 1.30 1.34 1.31 1.28 1.27 1.59 1.55 1.57 1.54 1.56 1.53

Potassium 1.31 1.35 1.47 1.52 1.51 1.52 0.90 0.81 0.95 1.00 1.00 1.01

Silica 13.3 13.5 11.9 11.7 11.2 11.5 9.41 9.44 9.51 9.87 9.56 9.83

Sodium 3.34 3.27 3.22 3.14 3.08 2.99 3.21 3.23 3.19 3.15 3.12 3.12

Sulfate 3.84 3.84 3.78 3.90 3.71 3.65 2.33 2.36 2.67 2.41 2.46 2.62
14 Quality of Water and Bottom Material in Breckenridge Reservoir, Virginia, September 2008 through August 2009

Alkalinity

Alkalinity is the ability of a solution to neutralize 

acids and buffer changes in pH. Alkalinity concentrations 

determined from water samples collected in Breckenridge 

Reservoir ranged from 4 to 15 mg/L as calcium carbonate 

(CaCO3) (app. 6). These concentrations were similar to those 

determined in samples collected from Lunga Reservoir which 

ranged from 3.3 to 13.9 mg/L as CaCO3 (Lotspeich, 2007). 

Alkalinity values varied little among the three reservoir 

sampling sites. The mean alkalinity concentration determined 

for samples collected from Breckenridge Reservoir during 

the study was 11.3 mg/L as CaCO3. By comparison, the mean 

alkalinity concentrations determined for the Chickahominy, 

Diascund Creek, and Little Creek Reservoirs were 18, 22, and 

24 mg/L as CaCO3, respectively (Lynch, 1992), and was 

6.3 mg/L as CaCO3 for Lunga Reservoir (Lotspeich, 2007). 

Silica

Silica (SiO2) usually is present in moderately abundant 

concentrations in freshwater lakes and reservoirs, ranging 

from 5 to 25 mg/L (Langmuir, 1997). Silicon (Si) is an 

element that influences algal production in many reservoirs, 

because diatoms (a type of algae) use silica in developing their 

skeletons, or frustules. This use of silica in the life cycle of 

diatoms can greatly reduce dissolved silica concentrations in 

surface waters. As a result, silica concentrations in lakes and 

reservoirs typically vary both spatially and seasonally.

Dissolved silica concentrations in samples collected 

from Breckenridge Reservoir ranged from 7.5 to 15.4 mg/L 

(app. 8). The mean dissolved silica concentration determined 

for the reservoir samples was 11.4 mg/L. By comparison, 

the mean dissolved silica concentrations determined for the 

Chickahominy, Diascund Creek, and Little Creek Reservoirs 

were 5.1, 3.6, and 1.8 mg/L, respectively (Lynch, 1992), and 

7.53 mg/L for the Lunga Reservoir (Lotspeich, 2007).

Pesticides

Water samples were collected and analyzed for pesticide 

concentrations in Breckenridge Reservoir to evaluate potential 

contamination resulting from the use of pesticides throughout 

the watershed. Samples were collected twice during the study 

at all three of the reservoir sampling locations. Samples were 

analyzed for 53 pesticides (app. 2) and only atrazine was 

found above the laboratory MRL of 0.007 μg/L. 

Atrazine is a widely used agricultural pesticide that 

has become increasingly controversial due to human-health 

concerns related to its presence in drinking-water supplies. 

Under the Safe Drinking Water Act, the U.S. Environmental 

Protection Agency has determined that no more than 3 parts 

per billion (ppb) of atrazine (as a running annual average) can 

be present in drinking water (National Resources Defense 

Council, 2011). Atrazine concentrations were 0.008 μg/L 

(0.008 ppb) near the surface and 0.010 μg/L (0.010 ppb) 

near the bottom at all three sampling sites. At the time of this 

publication, the SWCB has not listed an established criterion 

for atrazine concentrations.

Biological Constituents

Water samples collected from Breckenridge Reservoir 

were analyzed for Escherichia coliform (E. coli) bacteria 

because it is an indicator of fecal contamination from warmblooded animals. E. coli counts generally were low, ranging 

from 1 to 130 colonies per 100 mL (col/100 mL) (app. 6) 

of sample. None of the E. coli counts exceeded the SWCB 

water-supply standard of 126 col/100 mL, which is based on 

a geometric mean of two or more samples collected during 

any calendar month (Commonwealth of Virginia State Water 

Control Board, 2011). The maximum monthly geometric, 

three-sample mean E. coli colony count for Breckenridge 

Reservoir was 109 col/100 mL in May 2009. The second 

highest monthly geometric, three-sample mean E. coli colony 

count was 82 col/100 mL in December 2008 (fig. 10). 

Elevated bacteriological counts coincided with higher 

than-normal flow events in the tributary streams. For example, 

the reservoir sampling site located above South Branch 

Chopawamsic Creek had the highest E. coli colony count 

only once during the study, whereas the sampling site below 

South Branch Chopawamsic Creek had the highest count five 

times, as did the site at the dam. This suggests that the water 

quality of Breckenridge Reservoir is very closely related to the 

water quality in the tributary streams and that South Branch 

Chopawamsic Creek is the greatest source of E. coli bacteria 

to the reservoir.

Trophic Status

The trophic status of a reservoir is an indicator of its 

physical, chemical, and biological condition and is typically 

classified into one of four categories—oligotrophic, 

mesotrophic, eutrophic, or hypereutrophic. Lakes or reservoirs 

that can be categorized as oligotrophic have the most pristine 

conditions and those that are categorized as hypereutrophic 

have the poorest conditions. As a reservoir ages, its trophic 

condition evolves from oligotrophic to hypereutrophic. This 

evolution is natural but can be accelerated by human activities.

The trophic state index (TSI) is a method used to classify 

the trophic status of a reservoir and can be computed using 

near-surface total phosphorus concentrations (Carlson, 1977). 

TSI values based on total phosphorus concentrations (TSIP) 

for a reservoir are computed using the following equation:

TSIP = 14.42 ln(TP) + 4.15 

where 

TP = total phosphorus concentrations, in micrograms per liter.
Water Quality of Tributary Sites 15

Trophic state classifications based on the Carlson (1977) 

TSI are oligotrophic (0–30), mesotrophic (31–50), eutrophic 

(51–69), and hypereutrophic (greater than (>) 69). The TSIP

ranged from mesotrophic to eutrophic for all sites sampled in 

Breckenridge Reservoir. Surface TSIP values for all sampling 

sites in the reservoir indicated that the reservoir was generally 

mesotrophic with some fluctuation between mesotrophic and 

eutrophic during the summer. TSIP values for the samples that 

were pumped from near the bottom of the reservoir indicated 

generally eutrophic conditions.

Bottom-Material Quality

Bottom-material samples were collected on July 7, 2009, 

at all three sampling sites in the reservoir. These samples were 

analyzed for the following trace elements: arsenic, cadmium, 

chromium, cobalt, copper, iron, lead, manganese, mercury, 

nickel, phosphorus, selenium, and zinc. Concentrations of 

trace elements in the bottom material increased from the upper 

to the lower parts of the reservoir with samples from the upper 

site having the lowest concentrations (except cadmium) and 

the spillway site having the highest concentrations 

(table 8; fig. 1).

The SWCB currently has no criteria for concentrations 

of trace elements in bottom material in lakes and reservoirs. 

However, bottom material samples collected from Lunga 

Reservoir in 2004 were analyzed for many of the same trace 

elements (Lotspeich, 2007) as were analyzed in Breckenridge 

Reservoir bottom samples. Concentrations of most trace 

elements in bottom-material samples collected from 

Breckenridge Reservoir were higher than those in samples 

from Lunga Reservoir (table 9). Concentrations of trace 

elements such as iron and lead in bottom samples from 

Breckenridge Reservoir were 3 and 12 times higher, 

respectively, than concentrations in bottom samples collected 

from Lunga Reservoir. Bottom-material samples were not 

collected at the three tributary sites to determine if these 

relatively high trace-element concentrations were present 

upstream from the reservoir. 

Water Quality of Tributary Sites

Water-quality samples were collected and physical 

properties were measured at three stream sites, one located 

on each of the tributaries to Breckenridge Reservoir (fig. 1, 

sites 4–6; apps. 9–11). North Branch Chopawamsic Creek 

was sampled monthly, because it was part of another ongoing 

water-quality project for the USMC Quantico. Middle Branch 

and South Branch Chopawamsic Creeks were sampled five 

times—November 2008, and February, March, May, and 

August 2009. The USGS operated gaging stations on each 

of these tributary streams; therefore, streamflow data were 

available for each of these sites during the study.

Streamflow and selected water-quality indicators suggest 

a close relationship between Breckenridge Reservoir and its 

tributaries (fig. 10). The average monthly E. coli count, 

turbidity, and Secchi-disk depth determined for the three 

reservoir sites occurred very closely in time with increased 

streamflow in the tributaries. The maximum mean daily 

discharge was totaled for all three tributary streams in the 

7 days prior to collection of reservoir samples, and this 

cumulative discharge total was plotted, as shown in figure 10. 

No Data

0

20

40

60

80

100

120

Sept. Oct. Nov. Dec. Jan. Feb. Mar. April May June July Aug.

2008 2009

Average monthly E. coli—In colonies

per 100 milliliters

Average monthly Turbidity—Formazin

nephelometric units x 10

Average monthly Secchi depth—In feet x 10

Cumulative mean daily discharge - 7-day

period—In cubic feet per second

EXPLANATION

Figure 10. Monthly mean E. coli counts, turbidity measurements, and Secchi-disk depths, and cumulative mean daily 

discharges in tributary streams for sampling periods in Breckenridge Reservoir, Virginia.
16 Quality of Water and Bottom Material in Breckenridge Reservoir, Virginia, September 2008 through August 2009

Table 8. Concentrations of trace elements in bottom-material samples from Breckenridge Reservoir, Virginia, July 7, 2009.

[Site locations shown in figure 1. Concentrations are in micrograms per gram, except where noted. mg/kg, milligrams per kilogram]

Arsenic Cadmium

Chromium Cobalt Copper Iron Lead Manganese Mercury Nickel

Phosphorus

(mg/kg)

Selenium Zinc

Moisture 

content

(percenage)

Breckenridge Reservoir above South Branch Chopawamsic Creek near Joplin (site 3)

2.9 0.26 47.7 20.5 22.6 29,000 28 490 0.02 27.3 280 0.6 90.3 65

Breckenridge Reservoir below South Branch Chopawamsic Creek near Joplin (site 2)

4.0 0.22 55.4 25.8 47.9 47,000 190 880 0.04 30.6 74 0.7 106 73

Breckenridge Reservoir at Dam near Joplin (site 1)

6.7 0.34 79.9 61.4 73.2 76,000 380 1,400 0.06 43.2 800 1.0 152 86

Table 9. Mean trace-element concentrations in bottom 

material from Breckenridge and Lunga Reservoirs, Virginia

 [Concentrations are in micrograms per gram, except as noted.

mg/kg, milligrams per kilogram; <, less than]

Constituent Breckenridge 

Reservoir

Lunga

Reservoir1

Arsenic 4.53 1.44

Cadmium 0.27 0.24

Chromium 61.0 11.7

Copper 48.0 11.0

Iron 50,700 17,400

Lead 199 16.4

Manganese 923 432

Mercury 0.04 0.06

Nickel 33.7 9.17

Phosphorus (mg/kg) 385 502

Selenium 1.0 <1.0

Zinc 116 41.2

1From Lotspeich, 2007.
Summary 17

During the course of the study, increased turbidity and E. coli 

bacteria counts were observed during or after periods of 

increased tributary discharge, whereas Secchi-disk depths 

decreased during those same periods. 

Although no turbidity value was recorded in May 2009, 

the bacteriological samples collected that month yielded the 

highest average monthly E. coli colony count (109 col/100 mL) 

for Breckenridge Reservoir. Just one day prior to this sampling 

event, the cumulative mean daily discharge for the tributaries 

was the highest for the study period, 80 cubic feet per second 

(ft3

/s). The second highest cumulative mean daily discharge in 

the tributaries, 52 ft3

/s, occurred in December 2008 during the 

same period as the second highest E. coli count, 82 col/100 mL, 

and the highest recorded average turbidity value, 10.1 FNU. 

Conversely, the lowest average Secchi-disk depths occurred in 

December 2008 and May 2009, indicating a decrease in water 

clarity in the days immediately following periods of increased 

tributary streamflow.

Summary

Water samples were collected and physical properties 

were measured by the U.S. Geological Survey at three sites in 

Breckenridge Reservoir, and physical properties were measured 

at six additional reservoir sites from September 2008 through 

August 2009. Water samples were also collected and physical 

properties were measured in each of the three major tributaries 

to Breckenridge Reservoir: North Branch Chopawamsic 

Creek, Middle Branch Chopawamsic Creek, and South Branch 

Chopawamsic Creek. One site on each tributary was sampled 

five times during the study. 

The analytical results of reservoir and tributary samples 

collected and physical properties measured during this study 

were compared to ambient water-quality standards of the 

Virginia Department of Environmental Quality and Virginia 

State Water Control Board (SWCB). In general, the waterquality of Breckenridge Reservoir is similar to other reservoirs 

in the region, and the measurements made during this study 

indicate the reservoir is healthy and is not in violation of 

published SWCB ambient water-quality standards. 

Monthly profiles were conducted for water temperature, 

dissolved-oxygen concentrations, specific conductance, pH, and 

turbidity measured at 2-ft-depth intervals throughout the water 

column of the reservoir. These profiles were conducted at nine 

sites in the reservoir, and data values were measured at these 

sites from the water surface to the bottom of the reservoir. These 

profiles were conducted along three cross sections and were 

used to define the characteristics of the entire water column of 

the reservoir. 

During the study period, water temperatures measured 

throughout the water column at the nine Breckenridge Reservoir 

sites ranged from 3.2 to 27.7 °C, below the SWCB maximum 

water temperature ambient water-quality criteria of 32 °C. 

Dissolved-oxygen concentrations measured in the reservoir 

ranged from 2.8 to 11.7 mg/L, and fell below the SWCB 

minimum dissolved-oxygen ambient water-quality criterion 

of 4.0 mg/L at the surface of the reservoir at two sites in 

September 2008. Specific conductance values measured 

throughout the water column in the reservoir ranged from 36 

to 99 μS/cm, with a mean specific conductance of 52 μS/cm. 

Measurements of pH made throughout the water column of 

the reservoir ranged from 5.6 to 8.7 standard units, which fell 

within the SWCB pH ambient water-quality criterion of 6.0 to 

9.0 standard units, except for September 2008.

Water samples collected from Breckenridge Reservoir 

were analyzed for the species of nitrogen commonly present 

in water— nitrite, nitrate, ammonia, and organic nitrogen. 

Dissolved nitrite-nitrogen concentrations in samples collected 

from the reservoir were at or below the minimum reporting 

level of 0.002 mg/L. Dissolved nitrite-plus-nitrate nitrogen 

and dissolved ammonia-nitrogen concentrations ranged from 

less than the minimum reporting levels of 0.016 and 

0.01 mg/L, respectively, to 0.043 and 0.08 mg/L, respectively. 

Total nitrogen (the sum of the nitrogen species) concentrations 

ranged from 0.11 to 0.54 mg/L. Nutrient concentrations in 

samples that were collected near the bottom of the reservoir 

were similar to those in samples collected near the surface.

Concentrations of the major cations (calcium, 

magnesium, potassium, and sodium) and major anions 

(chloride, fluoride, and sulfate) in water samples collected from 

Breckenridge Reservoir generally were low, varied seasonally, 

and varied little spatially. Concentrations of cations and anions 

in the reservoir samples also did not vary when comparing 

the 1.0-ft depth samples with the near bottom samples. 

Concentrations of total organic carbon in samples collected at 

1.0-ft depth in the reservoir ranged from 2.3 to 9.8 mg/L, and 

concentrations of DOC dissolved organic carbon ranged from 

2.1 to 9.7 mg/L.

Water samples were analyzed for 53 pesticides, and 

only atrazine was found to be above the laboratory minimum 

reporting level. Atrazine concentrations of 0.008 and 

0.010 microgram per liter were found near the surface and 

bottom, respectively, at all three sampling locations. At the time 

of this publication, the Virginia State Water Control Board has 

not listed an established criterion for concentrations of atrazine.

Bottom material samples were collected for analysis of 

trace elements at all three reservoir sampling sites. 

Concentrations of arsenic, cadmium, and mercury in bottom 

material were similar to those analyzed in other reservoirs in the 

region. However, most other constituents that were collected 

from Breckenridge Reservoir, especially iron and lead, showed 

much higher concentrations than in the other reservoirs. 

Streamflow and select water-quality indicators suggest 

a close relationship between Breckenridge Reservoir and its 

tributaries. During the course of the study, increased turbidity 

and E. coli bacteria counts were observed during or after periods 

of increased tributary discharge, while Secchi-disk depths 

decreased during those same periods. These streamflow and 

water-quality indicators suggest a close relationship between 

Breckenridge Reservoir and its tributaries.
18 Quality of Water and Bottom Material in Breckenridge Reservoir, Virginia, September 2008 through August 2009

Selected References

Carlson, R.E., 1977, A trophic state index for lakes: 

Limnology and Oceanography, v. 22, p. 361–369.

Commonwealth of Virginia State Water Control Board, 2011, 

9 VAC 25-260—Virginia Water Quality Standards: 

143 p., accessed May 2011 at http://www.deq.virginia.gov/

wqs/documents/WQS_eff_6JAN2011.pdf

Goetz, S.J., Jantz, C.A., Prince, S.D., Smith, A.J., Varlyguin, D., 

and Wright, R., (2004), Integrated analysis of ecosystem 

interactions with land use change: The Chesapeake Bay 

watershed, in DeFries, R.S., Asner, G.P., and Houghton, 

R.A., eds., Ecosystems and land use change: Washington 

D.C., American Geophysical Union, Geophysical 

Monograph Series, 275 p.

Langmuir, D., 1997, Aqueous environmental geochemistry: 

Englewood Cliffs, N.J., Prentice-Hall, 600 p.

Lotspeich, R.R., 2007, The quality of water and bottom 

material in Lunga Reservoir, Virginia, September 2004 

through August 2005: U.S. Geological Survey Open-File 

Report 2007–1053, 52 p.

Lynch, D.D., 1992, Water quality and evaluation of raw-waterrouting scenarios, Chickahominy, Diascund Creek, and 

Little Creek Reservoirs, southeastern Virginia, 1983–86: 

U.S. Geological Survey Water-Resources Investigations 

Report 92–4034, 104 p.

Myers, D.N., and Wilde, F.D., eds., 2003, Biological 

indicators (3d ed.): U.S. Geological Survey Techniques of 

Water-Resources Investigations, book 9, chap. A7, accessed 

September 2004 at http://pubs.water.usgs.gov/twri9A7/.

National Resources Defense Council, 2011, Atrazine: 

Poisoning the well—Atrazine in public water systems and 

watersheds: Website, accessed August 2011 at http://www.

nrdc.org/health/atrazine/.

Wetzel, R.G., 2001, Limnology, lake and river ecosystems 

(3d ed.): San Diego, Calif., Academic Press, 1,006 p.

Wilde, F.D., Radtke, D.B., Gibs, Jacob, and Iwatsubo, R.T., 

eds., 1999, Collection of water samples: U.S. Geological 

Survey Techniques of Water-Resources Investigations, 

book 9, chap. A4, accessed September 2004 at 

http://pubs.water.usgs.gov/twri9A4/.

Woodside, M.D., 1994, Land use in, and water quality of, the 

Pea Hill Arm of Lake Gaston, Virginia and North Carolina, 

1988–90: U.S. Geological Survey Water-Resources Investigations Report 94–4140, 54 p.
Appendixes 19

Appendixes

Appendix 1. Laboratory reporting levels for major ions and nutrients analyzed in water 

samples collected from Breckenridge Reservoir, Virginia, September 2008 through 

August 2009.

Appendix 2. Laboratory reporting levels for pesticides analyzed in water samples 

collected from Breckenridge Reservoir, Virginia, September 2008 through August 2009.

Appendix 3. Summary of physical properties at various depths for Breckenridge 

Reservoir above Dam near Joplin, Virginia (01660030) and cross-section profiling points.

Appendix 4. Summary of physical properties at various depths for Breckenridge 

Reservoir below South Branch Chopawamsic Creek near Joplin, Virginia (01660020), 

and cross-section profiling points (fig. 1, site 2).

Appendix 5. Summary of physical properties at various depths for Breckenridge 

Reservoir above South Branch Chopawamsic Creek near Joplin, Virginia (01659700), 

and cross-section profiling points.

Appendix 6. Summary of various constituents at 1-foot depth at sampling sites in 

Breckenridge Reservoir, Virginia.

Appendix 7. Summary of nutrient concentrations at 1-foot depth at sampling sites in 

Breckenridge Reservoir, Virginia.

Appendix 8. Summary of dissolved major-ion concentrations at 1-foot depth at 

sampling sites in Breckenridge Reservoir, Virginia.

Appendix 9. Summary of water quality samples at North Branch Chopawamsic Creek 

near Independent Hill, Virginia.

Appendix 10. Summary of water quality samples at Middle Branch Chopawamsic Creek 

near Garrisonville, Virginia.

Appendix 11. Summary of water quality samples at South Branch Chopawamsic Creek 

near Garrisonville, Virginia.

Note: Appendixes–—Downloadable Excel and Word files are available online.
Prepared by

U.S. Geological Survey

Science Publishing Network

Raleigh Publishing Service Center

3916 Sunset Ridge Road

Ralieigh, NC 27607

A PDF version of this publication is available online at

http://pubs.usgs.gov/of/2011/1305/
Lotspeich—Quality of Water and Bottom Material in Breckenridge Reservoir, Virginia, September 2008 through August 2009—Open-File Report 2011–1305