U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2010–5093

Prepared in cooperation with the

New Jersey Department of Environmental Protection

Sediment Oxygen Demand in the Saddle River and 

Salem River Watersheds, New Jersey, 

July–August 2008
A.

Cover:

A. U.S. Geological Survey station 01391100, Hohokus Brook at mouth at Paramus, New Jersey. (Photograph by 

H. Heckathorn, U.S. Geological Survey)

B. U.S. Geological Survey station 01482537, Salem River at Courses Landing, New Jersey. (Photograph by 

H. Heckathorn, U.S. Geological Survey)

C. U.S. Geological Survey station 01391500, Saddle River at Lodi, New Jersey. (Photograph by H. Heckathorn, 

U.S. Geological Survey)

D. In situ deployment of a sediment oxygen demand chamber equipped with a multiparameter water-quality 

instrument. (Photograph by J. Gibs, U.S. Geological Survey)

C.

B.

D.
Sediment Oxygen Demand in the Saddle 

River and Salem River Watersheds, 

New Jersey, July–August 2008

By Heather A. Heckathorn and Jacob Gibs

Prepared in cooperation with the

New Jersey Department of Environmental Protection

Scientific Investigations Report 2010–5093

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: 2010

For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, 

natural hazards, and the environment, visit http://www.usgs.gov or call 1-888-ASK-USGS

For an overview of USGS information products, including maps, imagery, and publications, 

visit http://www.usgs.gov/pubprod

To order this and other USGS information products, visit http://store.usgs.gov

Suggested citation:

Heckathorn, H.A., and Gibs, J., 2010, Sediment oxygen demand in the Saddle River and Salem River watersheds, 

New Jersey, July–August 2008: U.S. Geological Survey Scientific Investigations Report 2010-5093, 10 p.

Any use of trade, product, or firm names is for descriptive purposes only and does not imply 

endorsement by the U.S. Government. Use of company names is for identification purposes only and does not imply 

responsibility.

Although this report is in the public domain, permission must be secured from the individual 

copyright owners to reproduce any copyrighted material contained within this report.
iii

Acknowledgments

The authors gratefully acknowledge Thomas Imbrigiotta of the USGS for help with data collection; James Jelinski of the USGS for manufacturing the chambers; Stewart Rounds of the USGS 

for technical advice; and Dale Simmons, Kara Watson, and Gregory Simpson of the USGS for 

editing, illustrations, and report layout. Administrative and technical assistance was provided 

by Barbara Hirst, Kimberly Cenno, Marzooq Al-Ebus, Patricia Ingelido, and Frank Klapinski of the 

NJDEP. 

v

Contents

Acknowledgments........................................................................................................................................iii

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

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

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

Study Areas............................................................................................................................................2

Methods and Procedures.............................................................................................................................2

Study Design..........................................................................................................................................2

Sediment Oxygen Demand Chambers...............................................................................................2

Sediment Oxygen Demand Chamber Deployments ........................................................................5

Calculation of Sediment Oxygen Demand ........................................................................................6

Sediment Oxygen Demand in the Saddle River and Salem River Watersheds ...................................7

Rates of Sediment Oxygen Demand ..................................................................................................7

Factors Affecting Sediment Oxygen Demand..................................................................................8

Composition of Streambed Material and Streamflow Regime.............................................8

Water-Column Oxygen Demand................................................................................................9

Summary..........................................................................................................................................................9

References Cited............................................................................................................................................9
vi

Tables

1. Site number, site name, and location of sediment-oxygen-demand monitoring 

sites in the Saddle River and Salem River watersheds, NJ ..................................................4

2. Rates of sediment oxygen demand and water temperature in the Saddle River 

watershed, NJ...............................................................................................................................7

3. Rates of sediment oxygen demand and water temperature in the Salem River 

watershed, NJ...............................................................................................................................8

4. Mean total organic carbon concentrations in streambed sediments in the 

Saddle River and Salem River watersheds, NJ.......................................................................9

Figures

1-2. Maps showing—

1. Location of study area, existing water-column water-quality sampling sites, 

and sediment-oxygen-demand monitoring sites in the Saddle River watershed, NJ ................................................................................................................................3

2. Location of study area, existing water-column water-quality sampling sites, 

and sediment-oxygen-demand monitoring sites in the Salem River watershed, NJ ................................................................................................................................4

3. Schematic diagram of sediment-oxygen-demand chamber.................................................5

4. Example graph showing turbidity and dissolved-oxygen depletion curve, showing 

the typical non-linear initial loss followed by a linear oxygen depletion at Major 

Run at Sharptown, NJ, on August 6, 2008.................................................................................6
vii

Conversion Factors

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square foot (ft2) 929.0 square centimeter (cm2)

square foot (ft2) 0.09290 square meter (m2)

square inch (in2) 6.452 square centimeter (cm2)

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2) 

Volume

quart (qt) 0.9464 liter (L) 

cubic inch (in3) 16.39 cubic centimeter (cm3) 

cubic inch (in3) 0.01639 liter (L)

cubic foot (ft3) 0.02832 cubic meter (m3) 

Flow rate

foot per second (ft/s) 0.3048 meter per second (m/s)

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

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

 °F=(1.8×°C)+32

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

 °C=(°F-32)/1.8

Horizontal coordinate information is referenced to the North American Datum of 1983 

(NAD 83).

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

Concentrations of chemical constituents in sediment are given in grams per kilogram (g/kg).

Sediment oxygen demand is given in grams of oxygen per square meter per day (g/m2d).

Abstract 

Many factors, such as river depth and velocity, biochemical oxygen demand, and algal productivity, as well as sediment 

oxygen demand, can affect the concentration of dissolved 

oxygen in the water column. Measurements of sediment oxygen demand, in conjunction with those of other water-column 

water-quality constituents, are useful for quantifying the 

mechanisms that affect in-stream dissolved-oxygen concentrations. Sediment-oxygen-demand rates are also needed to 

develop and calibrate a water-quality model being developed 

for the Saddle River and Salem River Basins in New Jersey to 

predict dissolved-oxygen concentrations. This report documents the methods used to measure sediment oxygen demand 

in the Saddle River and Salem River watersheds along with 

the rates of sediment oxygen demand that were obtained during this investigation. 

In July and August 2008, sediment oxygen demand was 

measured in situ in the Saddle River and Salem River watersheds. In the Saddle River Basin, sediment oxygen demand 

was measured twice at two sites and once at a third location; 

in the Salem River Basin, sediment oxygen demand was measured three times at two sites and once at a third location. 

In situ measurements of sediment oxygen demand in the 

Saddle River and Salem River watersheds ranged from 0.8 to 

1.4 g/m2d (grams per square meter per day) and from 0.6 to 

7.1 g/m2d at 20 degrees Celsius, respectively. Except at one 

site in this study, rates of sediment oxygen demand generally were low. The highest rate of sediment oxygen demand 

measured during this investigation, 7.1 g/m2d, which occurred 

at Courses Landing in the Salem River Basin, may be attributable to the consumption of oxygen by a large amount of 

organic matter (54 grams per kilogram as organic carbon) in 

the streambed sediments or to potential error during data collection. In general, sediment oxygen demand increased with 

the concentration of organic carbon in the streambed sediments. Repeated measurements made 6 to 7 days apart at the 

same site locations resulted in similar values.

Introduction

In accordance with the Federal Clean Water Act, the New 

Jersey Department of Environmental Protection (NJDEP) 

identified both the Saddle River below the confluence with 

Hohokus Brook in northeastern New Jersey and the Salem 

River in southwestern New Jersey as exceeding the State’s 

current (2008) Surface-Water-Quality Standard for total phosphorus of 0.1 mg/L and, therefore, designated these rivers as 

being impaired with respect to total phosphorus (New Jersey 

Department of Environmental Protection, 2010). Consequently, the U.S. Geological Survey (USGS), in cooperation 

with NJDEP, implemented a water-quality monitoring plan for 

these two unrelated watersheds.

NJDEP may establish a Total Maximum Daily Load 

(TMDL), the amount of a constituent that a water body can 

carry and still meet water-quality standards, for phosphorus in 

these water bodies. One type of impairment of the designated 

use (Freshwater 2 Nontrout) is excessive primary productivity, 

which in turn affects the concentration of dissolved oxygen 

in the water column (New Jersey Department of Environmental Protection, 2009). TMDLs for nutrients commonly 

are established with the assumption that low concentrations 

of dissolved oxygen are the result of excessive algal growth, 

which in turn results from the presence of excessive amounts 

of nutrients. 

Because dissolved oxygen is critical to the health and 

well-being of aquatic life, environmental officials in the 

State of New Jersey have established a minimum standard 

for dissolved oxygen in waterways throughout the State. To 

fully understand the characteristics of the water bodies, it is 

essential to quantify the mechanisms that affect concentrations 

of dissolved oxygen in these water bodies. Understanding a 

water body’s dissolved-oxygen budget requires knowledge of 

the sinks, as well as the sources, of dissolved oxygen. Many 

factors, such as river depth and velocity, biochemical oxygen 

demand, and algal productivity, as well as sediment oxygen 

demand (SOD), can affect the concentration of dissolved 

oxygen in the water column. One potentially important sink of 

dissolved oxygen that was studied in this investigation is SOD, 

which is the rate at which oxygen is depleted from the water 

column at or near the streambed sediment-water interface. As 

organic material settles out of the water column and is decomposed on the streambed, oxygen is consumed, depleting the 

oxygen that is available for biota. SOD, in conjunction with 

other water-quality constituents in the water column, is a critical measurement that will be needed to develop and calibrate 

a water-quality model that can be used by water managers to 

determine the importance of SOD in water-column dissolvedoxygen concentration and to determine whether a TMDL is 

needed for the impaired study basins. 

Sediment Oxygen Demand in the Saddle River and Salem 

River Watersheds, New Jersey, July–August 2008

By Heather A. Heckathorn and Jacob Gibs
2 Sediment Oxygen Demand in the Saddle River and Salem River Watersheds, New Jersey, July–August 2008

Purpose and Scope

This report documents measurements of SOD made at 

several locations in the Saddle River and Salem River watersheds. The rate of SOD was measured at three locations in 

each watershed. In the Saddle River watershed, SOD was 

measured twice at two sites and once at one additional site. In 

the Salem River watershed, SOD was measured three times 

at two sites and once at one additional site. All sampling took 

place during a period of stable base flow in July and August 

2008. 

Study Areas

The Saddle River is a tributary to the Passaic River. 

The headwaters of the Saddle River are in southeastern New 

York near the New Jersey-New York border, in the Piedmont 

physiographic province, in an urban area west of New York 

City. The Saddle River generally flows from north to south for 

approximately 12.2 mi to its confluence with Hohokus Brook, 

and then another 8.2 mi to the mouth of the Saddle River in 

Garfield, NJ. The drainage area of the Saddle River watershed 

is 61.0 mi2. The study reach on the main stem is relatively 

slow moving, with a velocity ranging from approximately 0.5 

to 1.4 ft/s during base-flow conditions, and generally has midchannel depths of approximately 2 to 3 ft and a channel width 

of 60 to 70 ft during base-flow conditions. River discharge 

is augmented by wastewater-treatment-plant effluent and is 

reduced by surface-water diversions. 

This investigation focuses on the lower part of the 

Saddle River (fig. 1) and one of its major tributaries, Hohokus 

Brook. Hohokus Brook receives 18.3 ft3/s of effluent from 

two wastewater-treatment plants in urban northeastern New 

Jersey (Storck and Nawyn, 2001), with a mean annual flow 

of 36.4 ft3/s for the period of record (1955–73, 1977–96, and 

2006–08) at Hohokus Brook at Ho-Ho-Kus, NJ. 

The Salem River watershed (fig. 2) lies in southwestern 

New Jersey, in the Inner Coastal Plain physiographic province, 

in a predominantly agricultural area, with the exception of 

the Borough of Woodstown, which is urban. The streamflow 

within the watershed is altered by a series of impoundments 

and agricultural or industrial diversions. One wastewatertreatment plant discharges 0.9 ft3

/s near the headwaters of the 

Salem River main stem (Zripko and Hasan, 1994). The drainage area of the Salem River watershed is 58.3 mi2

. The Salem 

River generally flows westward and is a tributary to the Delaware River. The headwaters of the Salem River are a series of 

six lakes. After the downstream-most lake, Memorial Lake, in 

Woodstown, the stream’s velocity ranges from approximately 

0.1 to 0.6 ft/s during base-flow conditions, mid-channel depths 

are approximately 1.5 ft, and channel width ranges from 20 

to 50 ft for approximately 4.1 mi until it approaches Courses 

Landing. 

Approximately 1.5 river miles upstream from Courses 

Landing and continuing throughout the downstream portions 

of the watershed, the river broadens and deepens, behaving 

more like a reservoir than a free-flowing stream for approximately 8.3 mi, with mid-channel depths of approximately 6 

to 8 ft and a channel width of nearly 150 ft along this reach 

at base-flow conditions. Stream velocities in this reach are 

extremely slow, approximately 0.03 ft/s, and nearly immeasurable. SOD monitoring in the Salem River watershed was 

focused on the upper portion of the watershed, from just below 

Memorial Lake to Courses Landing.

Methods and Procedures

The methods and procedures used in this investigation 

are reported below. These include the study design, sedimentoxygen-demand-chamber design and deployment, and the 

calculations involved in reporting sediment oxygen demand.

Study Design

Site selection was based on field reconnaissance in each 

of the targeted watersheds. Because the downstream reaches 

of the Salem River are deep and diving teams were not an 

available option to deploy chambers, site selection focused 

on the upper reaches of the watershed. To aid the planned 

water-quality modeling of the watershed, it was decided to 

deploy SOD chambers at existing water-column water-quality 

sampling sites. The chamber was deployed at one location per 

site where the streambed material and stream mixing were 

representative of the entire stream reach, and where it was 

possible to wade to the center of the channel. Because it was 

impossible to wade to the center of the Salem River channel at 

Courses Landing, chamber deployment at this site occurred at 

the only location that was accessible without diving.

Three sites in each watershed were chosen for SOD measurement (table 1). In the Saddle River watershed, two sites 

were on the main stem and one site was on Hohokus Brook, a 

tributary, just upstream from its confluence with Saddle River 

(fig. 1). The sites in the Salem River watershed included two 

on the main stem and one on a tributary, Major Run (fig. 2). 

One chamber was deployed two to three times within a 

6- to 12-day period at each monitoring site. Multiple deployments, spaced 6 to 7 days apart, at each site provided additional data to test for reproducibility of the SOD data.

Sediment Oxygen Demand Chambers

The SOD chambers and procedures for deployment 

and collection of data were modifications of those used by 

the USGS in previous studies conducted in Oregon (Doyle 

and Lynch, 2005; Doyle and Rounds, 2003; Wood, 2001; 

Rounds and Doyle, 1997). The chambers used in this study 

were open-bottom, aluminum cylinders designed to seat and 

seal in the streambed sediments. A multiparameter instrument 
Methods and Procedures1 3

Passaic

River

Hohokus

Brook

Saddle

River

PENNSYLVANIA

NEW YORK

DELAWARE

75° 74°

39°

40°

41°

0 10 20 40 MILES

0 10 20 40 KILOMETERS

ATLANTIC OCEAN

DELAWARE 

BAY

Saddle River

watershed

NEW JERSEY

*#

*#

XY

*#

*#

XY

$+

*#

*#

$+

*#

!(

01391540

01391500

01391110

01390518

01391100

01391070

01391050

01391000

01390946

01390700

410024074072000

01391200

Garfield

01390700

01391500

01391200

01391070

0 1 2 MILES

0 1 2 KILOMETERS

74°15' 74°10' 74°05' 74°

40°

55'

41°

41°

05'

NEW YORK

NEW JERSEY

EXPLANATION

*#

XY

$+

!(

Water-column water-quality sampling 

site and site number

Water-column water-quality sampling 

site and sediment-oxygen-demand 

monitoring site and site number

Sediment-oxygen-demand monitoring 

site and site number

Wastewater-treatment-plant sampling 

site and site number

Saddle River

watershed

Figure 1. Location of study area, existing water-column water-quality sampling sites, and sediment-oxygen-demand monitoring sites in 

the Saddle River watershed, NJ.
4 Sediment Oxygen Demand in the Saddle River and Salem River Watersheds, New Jersey, July–August 2008

Figure 2. Location of study area, existing water-column water-quality sampling sites, and sediment-oxygen-demand monitoring sites in 

the Salem River watershed, NJ.

Table 1. Site number, site name, and location of sediment-oxygen-demand monitoring sites in the Saddle River and Salem 

River watersheds, NJ.

U.S. Geological 

Survey site 

number

Site name Latitude Longitude

Saddle River watershed

01391100 Hohokus Brook at mouth at Paramus, NJ 40° 57’ 19” 074° 06’ 02”

01391200 Saddle River at Fair Lawn, NJ 40° 56’ 29” 074° 05’ 39”

01391500 Saddle River at Lodi, NJ 40° 53’ 25” 074° 04’ 50”

Salem River watershed

01482519 Salem River at Main Street, at Sharptown, NJ 39° 39’ 15” 075° 21’ 52”

01482530 Major Run at Sharptown, NJ 39° 38’ 56” 075° 22’ 28”

01482537 Salem River at Courses Landing, NJ 39° 39’ 38” 075° 24’ 33”

Sale m River

Major

Run

DELAWARE RIVER

*#

*#

*#

*#

$+

$+

$+

*# *#

XW

01482580 01482570

01482530

01482537

01482519

01482508

01482503

01482505

01482500

393855075195200

75°30' 75°25' 75°20' 75°15'

39°

45'

39°

40'

39°

35'

PENNSYLVANIA

0 0.7 1.4 MILES

0 0.7 1.4 KILOMETERS

EXPLANATION

XY

$+

Water-column water-quality sampling 

site and site number

Water-column water-quality sampling 

site and sediment-oxygen-demand 

monitoring site and site number

Wastewater-treatment-plant sampling 

site and site number

*#

Courses Landing

Memorial Woodstown Lake

01482505

01482530

393855075195200

Salem River

watershed

NEW JERSEY

PENNSYLVANIA

NEW YORK

DELAWARE

75° 74°

39°

40°

41°

0 10 20 40 MILES

0 10 20 40 KILOMETERS

ATLANTIC OCEAN

DELAWARE 

BAY

Salem River

watershed

NEW JERSEY
Methods and Procedures1 5

(YSI model 6920 V2, in this case) installed in the center of 

each chamber was equipped with sensors for water temperature, specific conductance, turbidity (YSI model 6136), and 

dissolved oxygen (YSI model 6150 ROX). The instrument 

was mounted vertically in the chamber inside a schedule 40, 

3-in.-diameter aluminum pipe and was sealed for an airtight 

connection. 

The chambers used in this study were not equipped with 

recirculating pumps because the dissolved-oxygen sensor was 

not affected by a minimum water velocity. In addition, it was 

thought that devising a way to deliver power to the mixing 

device within the chamber would compromise the gas- and 

water-tight seal of the chamber, which would have compromised the data. 

A schematic diagram of the chamber is shown in figure 3. 

The area covered by the chamber and the inside volume of the 

chamber are 312 in2 (0.2013 m2) and 2,594 in3 (0.0425 m3), 

respectively, corrected for the volume of the chamber’s bottom 

edges, which were submerged approximately 1.25 in. in the 

streambed, plus the volume occupied by the water-quality sensors (411 in3

, or 0.006735 m3).

Sediment Oxygen Demand Chamber 

Deployments

SOD chambers were deployed in July and August 2008 

during stable, base-flow conditions. Water temperatures 

ranged from 19 to 23oC and 18 to 27oC in the Saddle River 

and Salem River Basins, respectively, during this investigation; dissolved-oxygen readings for sites in the Saddle River 

and Salem River Basins ranged from 68 to 143 and 32 to 118 

percent of dissolved-oxygen saturation, respectively, during 

this investigation. The chambers were deployed long enough 

to observe a depletion of at least 1 mg/L of dissolved oxygen 

inside the chamber.

Two SOD-monitoring sites in the Saddle River watershed had two deployments, spaced 7 days apart, of one SOD 

ALUMINUM CHAMBER BODY

(MODIFIED 100-QUART STOCK POT)

1-INCH-DIAMETER RUBBER STOPPER

(FOUR PLACES) 

HANDLE

(OTHER HANDLE REMOVED)

3-INCH-DIAMETER ALUMINUM 

PIPE WELDED TO CHAMBER BODY

3-INCH FLEXIBLE COUPLING WITH 

TOP AND BOTTOM BAND CLAMPS

RUBBER BUSHING BETWEEN RUBBER 

COUPLING AND INSTRUMENT BODY

MULTIPARAMETER WATER-QUALITY 

INSTRUMENT

19.94 (506.40) SHARP EDGE

9.75 (247.65)

1.84 (46.74)

4.25 (107.95)

DISSOLVED-OXYGEN SENSOR

WITH WIPER

5.34 (135.71)

TURBIDITY SENSOR 

WITH WIPER

SPECIFIC-CONDUCTANCE AND 

WATER-TEMPERATURE SENSOR

SENSOR GUARD

Figure 3. Schematic diagram of sediment-oxygen-demand chamber. (Modified from J.C. Jelinski, U.S. Geological Survey, written 

commun., 2009; measurements are given in inches; measurements in parentheses are in millimeters.)
6 Sediment Oxygen Demand in the Saddle River and Salem River Watersheds, New Jersey, July–August 2008

chamber per visit. The third SOD-monitoring site in the 

Saddle River Basin had one deployment of one SOD chamber. 

Two sites in the Salem River watershed had three deployments, spaced 6 days apart, of one chamber per visit; the 

third site in the Salem River Basin had one deployment of 

one chamber. Sites were selected from existing water-column 

sampling locations in the Saddle River and Salem River watersheds (figs. 1 and 2) by satisfying the following criteria:

1. a minimum stream depth of 10 in. during base-flow conditions so that the top of the chamber was fully submerged,

2. streambed sediments that permit the bottom edge of the 

chamber to be submerged to a minimum depth of 1 in. to 

effectively seal the streamwater inside the chamber, and

3. historical DO data and other water-quality data indicating 

probable large swings in diurnal DO or not meeting the 

in-stream standard for DO.

A multiparameter instrument was used for the chamber 

measurements and was programmed to electronically record 

measurements of water temperature, specific conductance, dissolved oxygen, and turbidity at 3-minute intervals. The wipers 

on the optical sensors, for turbidity and dissolved oxygen, 

were programmed to sequentially wipe each sensor three 

times before each measurement. There were no concentration 

gradients caused by the water-quality instrumentation because, 

unlike a polarographic dissolved-oxygen sensor, the optical 

DO sensor does not consume oxygen (Yellow Springs Instruments Inc., 2006). 

The calibrated multiparameter water-quality instrument 

was installed in the chamber upon arrival at the SOD-monitoring site. All deployments in this study were accomplished by 

wading. A hand-held display unit was connected to the instrument using a data-transmission cable. With the ports in the top 

of the chamber open to allow air to escape when the chamber 

was submerged, the chamber with the multiparameter instrument was carried into the stream. The chamber was maneuvered to allow any trapped air to escape through the ports, and 

was gently seated so the bottom edge penetrated the streambed 

sediments to a depth of approximately 1.25 in. The four ports 

in the top of the chamber then were closed with rubber stoppers. The data acquired were monitored from the hand-held 

display on the streambank. When a decrease in dissolvedoxygen concentration of at least 1 mg/L was observed, the 

measurement of SOD was deemed to be complete. The SOD 

measurement generally occurred over a span of approximately 

5 to 6 hours. Post-calibration checks were performed on the 

multiparameter instrument after the chamber was retrieved. 

Post-calibration checks showed minimal instrument drift or 

fouling and, therefore, the instrument was not a source of 

error.

Calculation of Sediment Oxygen Demand

The SOD rate was calculated using two methods. In both 

methods, the typical, nonlinear decrease in dissolved-oxygen 

concentration during the first several minutes or, sometimes, 

hour of the chamber deployment while turbidity was decreasing was disregarded (fig. 4). In previous investigations, this 

0 1 2 3 4 5

0

1

2

3

4

5

0

Nonlinear decrease 

in dissolved-oxgyen 

concentration

DISSOLVED-OXYGEN CONCENTRATION, 

IN MILLIGRAMS PER LITER

TURBIDITY, IN FORMAZIN NEPHELOMETRIC UNITS

ELAPSED TIME, IN HOURS

0.5 1.5 2.5 3.5 4.5

4.5

3.5

2.5

1.5

0.5

700

600

500

400 

300

200

100

Disregarded data

Dissolved oxygen

Turbidity

Line of best fit

f(x) = -0.2478 x + 3.5012

R2 = 0.8954

Point after turbidity inflection

Figure 4. Example graph showing turbidity and dissolved-oxygen depletion curve, showing the typical non-linear initial loss followed 

by a linear oxygen depletion at Major Run at Sharptown, NJ, on August 6, 2008.
Sediment Oxygen Demand in the Saddle River and Salem River Watersheds1 7

nonlinear decrease in dissolved-oxygen concentration has been 

attributed to the suspension of streambed sediments in the 

water column for a period of time until the sediments settled 

back to the sediment surface (Rounds and Doyle, 1997). After 

the rate of change of turbidity reached a constant, the SOD 

rate was assumed to be representative of the SOD at the monitoring site and not caused by any suspension of sediments that 

occurred during the installation of the chamber.

In the first method, dissolved-oxygen concentrations were 

plotted on a graph as a function of elapsed time, resulting in a 

dissolved-oxygen depletion curve. The slope of the linear part 

of the oxygen-depletion curve was determined through linear 

regression and used to calculate the SOD rate:

SOD V T A b = 1 4. ( 4 / ) , (1)

where SODT is the sediment oxygen demand rate, in 

grams per square meter per day, at water temperature T; V is 

the volume of water in the chamber, in liters; A is the area of 

the streambed sediment covered by the chamber, in square 

meters; b is the slope of the oxygen-depletion curve, in milligrams per liter per minute; and 1.44 is a units-conversion 

constant.

SOD rates were corrected to 20oC using a standard van’t 

Hoff equation:

SOD SODT

T

20

20 = 1 065 − / . ( ) , (2)

where SOD20 is the sediment oxygen demand rate, in 

grams per square meter per day, at 20oC and T is the water 

temperature, in degrees Celsius (Thomann and Mueller, 1987). 

Although this correction does not hold true for water temperatures less than 10o

C (Rounds and Doyle, 1997), water temperatures in the Saddle and Salem River watersheds in this study 

ranged from 19 to 23oC and 18 to 27oC, respectively. 

In the second method, because the dissolved-oxygen 

concentration was recorded every 3 minutes, SOD rates also 

could be calculated every 3 minutes, using the above equations; these calculations result in an average SODT and SOD20

over an interval of time. 

Sediment Oxygen Demand in the 

Saddle River and Salem River 

Watersheds

SOD measurements at Saddle River and Salem River 

mainstem locations as well as at locations on selected tributaries are documented in this section. Rates of SOD and factors 

affecting them are also discussed. 

Rates of Sediment Oxygen Demand

Using the slope of the oxygen-depletion curve to calculate SOD, SOD20 in the Saddle River watershed ranged from 

0.8 to 1.4 g/m2d on the main stem and tributary (table 2). 

Using the same method to calculate SOD, SOD20 in the Salem 

River watershed ranged from 0.6 to 2.0 g/m2d, with the exception of a value of 7.1 g/m2

d at Salem River at Courses Landing 

(table 3). 

This investigation included a site on the Salem River 

at Main Street in Sharptown, which is within 0.3 river mi of 

Site 2 in a previous study by Najarian Associates (Litwack 

and Najarian, 1990). The SOD20 results for this site in this 

study and in the study by Najarian Associates in 1989 are both 

low. The median SOD20 in this investigation was 1.0 g/m2d, 

whereas the median value in the Najarian Associates study 

was 2.03 g/m2d (Litwack and Najarian, 1990). 

Differences in these results may stem partly from the fact 

that Najarian Associates measured SOD using the laboratory 

method, whereas in this study, SOD was measured using an 

in situ method. The in situ technique is a direct measurement 

of SOD that is made in the field under ambient conditions, 

whereas the laboratory technique involves coring streambed 

sediments for later measurement of oxygen depletion in a 

controlled setting (Bowman and Delfino, 1979). Although 

each technique has advantages and disadvantages, the in situ 

method was used in this study because it does not disturb 

ambient conditions, streambed sediments, or aquatic biota during measurement.

Table 2. Rates of sediment oxygen demand and water temperature in the Saddle River watershed, NJ.

[Data are available at the U.S. Geological Survey, NJ Water Science Center in West Trenton, NJ; deg C, degrees Celsius; SODT, rate of sediment oxygen demand at river-water temperature; SOD20, rate of sediment oxygen demand corrected to 20 degrees Celsius; g/m2

d, grams of oxygen per square 

meter per day]

U.S. Geological 

Survey site 

number

Site name Date

Water 

temperature 

(deg C)

Linear-regression method Three-minute method

SODT

(g/m2d)

SOD20

(g/m2d)

SODT

(g/m2d)

SOD20

(g/m2d)

01391100 Hohokus Brook at mouth at 

Paramus, NJ

8/20/2008 22.0 0.9 0.8 1.3 1.2

8/27/2008 21.5 1.3 1.2 1.5 1.4

01391200 Saddle River at Fair Lawn, NJ 8/20/2008 20.6 1.4 1.4 1.3 1.3

01391500 Saddle River at Lodi, NJ 8/20/2008 22.1 1.5 1.4 1.7 1.5

8/27/2008 20.4 1.4 1.4 1.1 1.0
8 Sediment Oxygen Demand in the Saddle River and Salem River Watersheds, New Jersey, July–August 2008

To determine the variability of the results and the precision of the measurements, and because measurements were 

replicated, albeit 6 to 7 days apart, relative percent difference 

was calculated using 10 SOD20 results that were determined 

by the linear regression method. The average of the relative 

percent differences was 18 percent for all deployments in the 

Saddle and Salem Rivers.

Factors Affecting Sediment Oxygen Demand

Factors affecting sediment oxygen demand are discussed 

below. Likely factors affecting SOD, such as the chemical and 

biological composition of the streambed materials and watercolumn oxygen demand, are discussed.

Composition of Streambed Material and 

Streamflow Regime

The rates of oxygen depletion at the sediment-water 

interface vary, possibly depending on the composition of 

streambed material. Streambed sediments at sampling locations in the Saddle River watershed are primarily sand or 

gravel, whereas those at sites in the Salem River watershed 

are composed of silt and organic material. In both watersheds, 

the rates of SOD seem to track the total carbon content of 

streambed sediments. The carbon in the streambed sediments 

was predominantly organic carbon in both watersheds. The 

mean concentration of organic carbon in streambed sediment from nine locations in the Saddle River watershed was 

2.5 g/kg (table 4). The mean concentration of organic carbon 

in streambed sediments from six locations in the Salem River 

watershed upstream from Courses Landing was 4.0 g/kg, 

whereas the mean concentration of organic carbon in streambed sediments at Salem River at Courses Landing was 54 g/kg 

(table 4). (These data are stored in the USGS National Water 

Information System (NWIS) database available at the USGS 

Web site http://waterdata.usgs.gov/nj/nwis.) The SOD rate at 

Courses Landing was much greater than the rates calculated 

for upstream portions of the watershed. 

Additionally, the Courses Landing site lies in the 

reservoir-like reach of the Salem River, where the river’s 

mean velocity is 0.04 ft/s during base-flow conditions (U.S. 

Geological Survey, 2009). The reach at Courses Landing is 

an area of sediment deposition; in a span of 3 river miles, the 

cross-sectional area of the channel increases from approximately 50 ft2

 at Salem River at Main Street at Sharptown to 

approximately 500 ft2 at Salem River at Courses Landing as a 

result of the presence of downstream dams. The slow velocities in the pooled section of the river allow a large amount of 

organic material to settle to the stream bottom, where it can 

decompose and increase the rate of oxygen depletion. Aerobic 

decomposition of the organic carbon in the streambed sediments at the streambed sediment-water interface consumes 

oxygen and, therefore, affects the rate of oxygen depletion. 

It is also possible, however, that the organic matter at the 

Courses Landing site could be oxidized through chemical 

and physical processes that consume oxygen. Sediments in 

the pooled reach of the river are likely more susceptible to 

decomposition, and consequently demand more oxygen, than 

the organic matter in the upstream reaches of the watershed.

The streambed material in the wadeable sections at 

Salem River at Courses Landing is primarily a thin layer of 

organic matter underlain by construction debris that may have 

prevented the chamber from being completely sealed on the 

streambed, resulting in a high rate of SOD. For these reasons, 

along with the inability to wade to a suitable location for 

chamber deployment due to stream depths, the in situ measurement of SOD was not repeated at Salem River at Courses 

Landing.

Table 3. Rates of sediment oxygen demand and water temperature in the Salem River watershed, NJ.

[Data are available at the U.S. Geological Survey, NJ Water Science Center in West Trenton, NJ; deg C, degrees Celsius; SODT, rate of sediment oxygen demand at river-water temperature; SOD20, rate of sediment oxygen demand corrected to 20 degrees Celsius; g/m2

d, grams of oxygen per square 

meter per day]

U.S. Geological 

Survey site 

number

Site name Date

Water 

temperature 

(deg C)

Linear-regression method Three-minute method

SODT

(g/m2d)

SOD20

(g/m2d)

SODT

(g/m2d)

SOD20

(g/m2d)

01482519 Salem River at Main Street, at 

Sharptown, NJ

7/31/2008 24.0 0.8 0.6 1.0 0.8

8/06/2008 22.9 1.2 1.0 1.2 1.0

8/12/2008 20.4 1.2 1.1 1.2 1.1

01482530 Major Run at Sharptown, NJ 7/31/2008 26.0 3.0 2.0 3.0 2.1

8/06/2008 25.9 1.4 1.0 1.5 1.0

8/12/2008 21.3 1.5 1.4 1.8 1.6

01482537 Salem River at Courses Landing, NJ 8/06/2008 26.4 10.5 7.1 11.6 7.8
References Cited1 9

Water-Column Oxygen Demand

Water-column samples from the Salem River watershed 

were analyzed for 5-day carbonaceous biochemical oxygen 

demand (CBOD5) as part of a broader water-column waterquality study co-occurring with this investigation. The CBOD5

for those samples was relatively low (generally less than 

2 mg/L during base-flow conditions) in this study; historical data (from November 1997 to November 2002) for the 

Saddle River watershed generally also show low concentrations (median less than 3 mg/L) of 5-day biochemical oxygen 

demand (BOD5) during base-flow conditions. For CBOD5

results near the reporting level of 2 mg/L and a measurement 

of 3 mg/L, the variability of the measurement of CBOD5 is 

very large, with relative standard deviations of 46 and 38 

percent, respectively (American Public Health Association, 

American Water Works Association, and Water Environment 

Federation, 1998). Given the low water-column biochemical oxygen demand in the Saddle River and Salem River 

watersheds and the relatively poor precision of the analysis 

of CBOD5 at low CBOD5 concentrations in the study areas, 

water-column oxygen demand blanks may introduce a large 

error in determining SOD. 

Summary

Along with river depth and velocity, biochemical oxygen 

demand, and algal productivity, SOD is one factor that can 

alter the water-column dissolved-oxygen concentration. Therefore, the USGS, in cooperation with the NJDEP, measured 

SOD rates using in situ techniques at three sites on the main 

stems and tributaries of the Saddle and Salem Rivers. SOD20

ranged from 0.8 to 1.4 g/m2d in the Saddle River watershed 

and from 0.6 to 2.0 g/m2d in the Salem River watershed, with 

the exception of a measurement of 7.1 g/m2d at Salem River at 

Courses Landing. The high rate of SOD that was measured at 

Courses Landing may have resulted from high concentrations 

of organic carbon (54 g/kg) in the streambed sediments. In 

general, sediment oxygen demand increased with the organiccarbon content of the streambed sediments.

References Cited

American Public Health Association, American Water Works 

Association, and Water Environment Federation, 1998, 

Standard methods for the examination of water and wastewater (20th ed.): Baltimore, MD, American Public Health 

Association, p. 5-2–5-6.

Table 4. Mean total organic-carbon concentrations in streambed sediments in the Saddle River and Salem River watersheds, 

NJ.

U.S. Geological 

Survey site 

number

Site name

Mean total organiccarbon concentration 

(grams per kilogram)

Saddle River watershed

01390518 Saddle River at Grove Street, at Ridgewood 0.6

01390700 Hohokus Brook at Wyckoff, NJ 2.2

01390946 Hohokus Brook at Waldwick Avenue, at Waldwick, NJ 4.9

01391000 Hohokus Brook at Ho-Ho-Kus, NJ 3.2

01391050 Hohokus Brook at Grove Street, at Ridgewood, NJ 2.7

01391100 Hohokus Brook at mouth at Paramus, NJ 3.1

01391110 Saddle River at Paramus 1.6

01391500 Saddle River at Lodi, NJ 1.3

01391540 Saddle River at Felician College footbridge, at Lodi, NJ 3.3

Salem River watershed

01482500 Salem River at Woodstown, NJ 3.6

01482503 Chestnut Run at Woodstown, NJ 2.7

01482505 Salem River at Rt-40, at Woodstown, NJ 3.8

01482508 Salem River at Rt-40, at Sharptown, NJ 3.8

01482519 Salem River at Main Street, at Sharptown, NJ 7.4

01482530 Major Run at Sharptown, NJ 2.7

01482537 Salem River at Courses Landing, NJ 54
10 Sediment Oxygen Demand in the Saddle River and Salem River Watersheds, New Jersey, July–August 2008

Bowman, G.T., and Delfino, J.J., 1979, Sediment oxygen 

demand techniques: A review and comparison of laboratory 

and in-situ systems: Water Research, v. 14, p. 491–499.

Doyle, M.C., and Lynch, D.D., 2005, Sediment oxygen 

demand in Lake Ewauna and the Klamath River, Oregon, 

June 2003: U.S. Geological Survey Scientific Investigations 

Report 05-5228, 14 p.

Doyle, M.C., and Rounds, S.A., 2003, The effect of chamber 

mixing velocity on bias in measurement of sediment oxygen 

demand rates in the Tualatin River, Oregon: U.S. Geological Survey Water-Resources Investigations Report 03-4097, 

16 p.

Litwack, H.S., and Najarian, T.O., 1990, Impact analysis of 

a wastewater discharge on the water quality of the Salem 

River: West Eatontown, NJ, Najarian Associates, L.P., Final 

Project Report, April 1990, 133 p. 

New Jersey Department of Environmental Protection, 2010, 

Surface water quality standards: New Jersey Department of 

Environmental Protection, N.J.A.C 7:9B, accessed February 25, 2010, at http://www.nj.gov/dep/rules/rules/

njac7_9b.pdf.

New Jersey Department of Environmental Protection, 2009, 

New Jersey integrated water quality monitoring and assessment report, Appendix A, accessed February 25, 2010, at 

http://www.state.nj.us/dep/wms/bwqsa/2008_revised_final_

Integrated_List.pdf.

Rounds, S.A., and Doyle, M.C., 1997, Sediment oxygen 

demand in the Tualatin River Basin, Oregon, 1992-96: U.S. 

Geological Survey Water-Resources Investigations 

Report 97-4103, 19 p.

Storck, D.A., and Nawyn, J.P., 2001, Reconstruction of 

streamflow records in the Passaic and Hackensack River 

basins, New Jersey and New York, water years 1993–96: 

U.S. Geological Survey Water-Resources Investigations 

Report 01-4078, 89 p.

Thomann, R.V., and Mueller, J.A., 1987, Principles of surface 

water quality modeling and control: New York, Harper and 

Rowe, p. 291–293.

U.S. Geological Survey, 2009, National Water Information 

System: Web interface, accessed June 26, 2009, at http://

waterdata.usgs.gov/nj/nwis/.

Wood, T.M., 2001, Sediment oxygen demand in Upper Klamath and Agency Lakes, Oregon, 1999: U.S. Geological Survey Water-Resources Investigations Report 01-4080, 13 p.

Yellow Springs Instruments Inc., 2006, Operating manual for 

YSI 6-series environmental monitoring systems, 324 p., 

accessed July 6, 2009, at http://www.ysi.com/media/

pdfs/069300-YSI-6-Series-Manual-RevF.pdf.

Zripko, N.P., and Hasan, A., 1994, Depletive water use project 

for regional water resource planning areas of New Jersey: 

Trenton, NJ, New Jersey Department of Environmental Protection, Appendix A—Depletive water use data, p. A33.
For additional information, write to:

Director

U.S. Geological Survey

New Jersey Water Science Center

Mountain View Office Park

810 Bear Tavern Rd., Suite 206

West Trenton, NJ 08628

or visit our Web site at:

http://nj.usgs.gov/
Heckathorn and Gibs—Sediment Oxygen Demand in the Saddle River and Salem River Watersheds, New Jersey, July–August 2008—Scientific Investigations Report 2010–5093