QUALITY OF WATER IN TRIBUTARIES TO THE UPPER DELAWARE 

RIVER, NEW JERSEY, WATER YEARS 1985-2001

• Measurements of nine chemical 

constituents and properties indicate that 

median concentrations of nitrate plus 

nitrite and total phosphorus and levels 

of fecal coliform bacteria were lower, 

and median concentrations of dissolved 

oxygen were higher, in samples from 

streams in the Upper Delaware River 

watershed than in samples from 

randomly selected streams across New 

Jersey.

• Concentrations of nutrients and 

dissolved and suspended solids, 

levels of fecal coliform bacteria, and 

water temperatures were lowest, and 

concentrations of dissolved oxygen 

were highest at sites on Dunnfield 

Creek, Flat Brook, and Vancampens 

Brook.

• Concentrations of nutrients and 

dissolved and suspended solids, fecal 

coliform bacteria levels, pH, and water 

temperatures generally were highest 

at sites on the Musconetcong River, 

Pohatcong Creek, the Pequest River, 

and the Paulins Kill.

• Fecal coliform bacteria, total phosphorus 

concentration, and water temperature 

are the water-quality measures that 

most frequently failed to meet waterquality reference levels.

• Concentrations of most chemical 

constituents studied and levels of fecal 

coliform bacteria were lowest, and 

concentrations of dissolved oxygen 

were highest, in streams whose 

watersheds contain the most forested or 

most undeveloped land.

• No significant trend over time was 

found for most of the constituents and 

properties at most of the 10 sites for 

which a trend test was conducted; 

however, concentrations of total 

phosphorus and un-ionized ammonia 

decreased at 5 or more of these sites. 

Water temperature and pH decreased, 

but concentrations of nitrate plus nitrite, 

dissolved oxygen, and dissolved-solids 

increased, at fewer than half of these 

sites.

U.S. Department of the Interior

U.S. Geological Survey

USGS Fact Sheet FS-090-02

September 2002

The U.S. Geological Survey (USGS), in cooperation with the New Jersey Department 

of Environmental Protection (NJDEP) and North Jersey Resource Conservation 

and Development Council, evaluated the quality of surface water in Watershed 

Management Area 1 (WMA1), a 746-mi2 (square miles) area in northwestern New 

Jersey that covers the Upper Delaware River watershed (fig. 1). Study results can 

be used for watershed-management planning and as background data for a planned 

preliminary assessment of the nonpoint- and point-source loads to streams in the 

study area. This Fact Sheet summarizes data on the quality of water in the tributaries 

to the Upper Delaware River in the study area with respect to instream reference 

levels, trends at sampling sites, variability with season and flow condition, relation 

Figure 1. Location of water-quality sampling sites in the Upper Delaware 

River Basin study area, New Jersey.

DRBCNJ0035

EWQ5

EWQ2

75°00'

75°45'

41°15'

41°00'

40°45'

Upper Delaware

River Watershed

study area

New

Jersey

Pequest River

Delaware River

Paulins Kill

Flat Brook

Musconetc ong River

Study area

Subbasin boundary

Delaware River Basin Commission sites

Delaware River Basin Commission

Delaware River Basin Commission

and U.S. Geological Survey (USGS)/

New Jersey Department of Environmental

Protection (NJDEP) network

USGS sites

National Water-Quality Assessment

USGS/NJDEP network

NJDEP Existing Water Quality

(EWQ) site

EXPLANATION

(see table 1)

0 5 MILES

0 5 KILOMETERS

01457400

01457000

01456600

01456200

01445500

01446400

01455801 01455500

01444970

01445000

01439830

DRBCNPS47

01443370

01443440

01443290

DRBCNJ0028

DRBCNJ0025

01455200

DRBCNJ0030

01442760

01443600

01443500

DRBCNPS0025

DRBCNJ0036

DRBCNJ0033

DRBCNJ0031

DRBCNPS2251

DRBCNPS2252

DRBCNPS321

DRBCNPS0032

01440000

01440010

01443550

DRBCNPS31

EWQ3

EWQ4

EWQ1

EWQ6

DRBCNJ0027
to land use in the drainage areas upstream from the sites, 

comparison with data from statewide sampling networks, and 

changes in water quality along stream reaches.

Description of Study Area

The Upper Delaware River study area (fig. 1) consists of 

approximately 744 mi2 in parts of Hunterdon, Morris, Sussex, and 

Warren Counties in northwestern New Jersey and an additional 

2 mi2 of the Clove Brook subwatershed in New York State. The 

study area contains 14 tributaries whose drainage areas cover 

more than 2 mi2 that drain to the Delaware River in WMA1 from 

the Musconetcong River north to the New York State border. The 

largest of these tributaries are the Paulins Kill, Pequest River, and 

Musconetcong River.

The Upper Delaware River drains parts of two physiographic 

provinces (fig. 2). The New England Province covers the 

southeastern one-third of the study area. This area is underlain 

predominantly by granite, gneiss, and small amounts of marble, all 

of which are resistant to erosion. Limestone underlies the valley 

areas. The Valley and Ridge Province covers approximately the 

northwestern two-thirds of the study area. The area is underlain 

by faulted and folded sedimentary layers of sandstone, shale, 

and limestone. Alternating belts of erosion-resistant sandstone 

and easily eroded shale and limestone create the long, parallel, 

northeast-southwest-trending ridges and valleys that are 

characteristic of the province (N.J. Department of Environmental 

Protection, 1992).

Site number

(see figure 1)

Site name

01439830, EWQ7 BIG FLAT BROOK AT TUTTLES CORNER, N.J.

01440000 FLAT BROOK NEAR FLATBROOKVILLE, N.J.

01440010 FLAT BROOK AT FLATBROOKVILLE, N.J.

01442760, DRBCNJ0038 DUNNFIELD CREEK AT DUNNFIELD, N.J.

01443290 PAULINS KILL UPSTREAM FROM NJ ROUTE 15 AT LAFAYETTE, N.J.

01443370, EWQ8 DRY BROOK AT COUNTY ROUTE 519 NEAR BRANCHVILLE, N.J.

01443440, EWQ9 PAULINS KILL AT BALESVILLE, N.J.

01443500 PAULINS KILL AT BLAIRSTOWN, N.J.

01443550 JACKSONBURG CREEK NEAR MILLBROOK, N.J.

01443600 JACKSONBURG CREEK NEAR BLAIRSTOWN, N.J.

01444970 PEQUEST RIVER AT ROUTE 206 BELOW SPRINGDALE, N.J.

01445000, EWQ10 PEQUEST RIVER AT HUNTSVILLE, N.J.

01445500, EWQ11 PEQUEST RIVER AT PEQUEST, N.J.

01446400, DRBCNJ0033 PEQUEST RIVER AT BELVIDERE, N.J.

01455200, EWQ14 POHATCONG CREEK AT NEW VILLAGE, N.J.

01455500 MUSCONETCONG RIVER AT OUTLET OF LAKE HOPATCONG, N.J.

01455801 MUSCONETCONG RIVER AT LOCKWOOD, N.J.

01456200, EWQ15 MUSCONETCONG RIVER AT BEATTYSTOWN, N.J.

01456600 MUSCONETCONG RIVER AT HAMPTON, N.J

01457000 MUSCONETCONG RIVER NEAR BLOOMSBURY, N.J.

01457400, DRBCNJ0025 MUSCONETCONG RIVER AT RIEGELSVILLE, N.J.

DRBCNPS0047 SHIMERS BROOK AT ROUTE 521 AT MONTAGUE, N.J.

DRBCNPS2251 LITTLE FLAT BROOK AT PETERS VALLEY, N.J.

DRBCNPS2252 BIG FLAT BROOK AT PETERS VALLEY, N.J.

DRBCNPS0321 FLAT BROOK AT WALPACK CENTER, N.J.

DRBCNPS0032 FLAT BROOK AT OLD MINE ROAD AT FLATBROOKVILLE, N.J.

DRBCNPS0031 VANCAMPENS BROOK AT OLD MINE ROAD NEAR MILLBROOK, N.J.

DRBCNJ0036 PAULINS KILL AT ROUTE 46 BRIDGE AT COLUMBIA, N.J.

DRBCNJ0035 DELAWANNA CREEK AT ROUTE 46 AT KNOWLTON TOWNSHIP, N.J.

DRBCNJ0031 POPHANDUSING BROOK AT SPRING STREET AT BELVIDERE, N.J.

DRBCNJ0030, EWQ12 BUCKHORN CREEK AT HUTCHINSON, N.J.

DRBCNJ0028 LOPATCONG CREEK AT MAIN STREET AT PHILLIPSBURG, N.J.

DRBCNJ0027, EWQ13 POHATCONG CREEK AT ROUTE 519 AT POHATCONG TOWNSHIP, N.J. 

EWQ1 CLOVE BROOK AT DUTTONVILLE, N.J.

EWQ2 BEAVER BROOK AT SAREPTA, N.J.

EWQ3 LOPATCONG CREEK AT PORT WARREN, N.J.

EWQ4 LUBBERS RUN AT LOCKWOOD, N.J.

EWQ5 MUSCONETCONG RIVER AT NEW HAMPTON, N.J.

EWQ6 LITTLE FLAT BROOK AT SANDYSTON TOWNSHIP, N.J.

Table 1. Surface-water-quality sites in the U.S. Geological Survey (USGS)/New Jersey Department of 

Environmental Protection (NJDEP), USGS National Water Quality Assessment program, and Delaware River 

Basin Commission (DRBC) networks sampled during 1984-2000, and NJDEP Existing Water Quality (EWQ) sites 

sampled in 2001, Upper Delaware River Basin, New Jersey

[Sites with eight-digit numbers are USGS or USGS/NJDEP sites; site numbers preceded by “DRBC” and “EWQ” 

are DRBC and EWQ sites, respectively]
Figure 2. 1995/97 land use and physiographic provinces in the Upper Delaware River Basin study area, 

New Jersey.

0 5 MILES

0 5 KILOMETERS

75°00'

75°45'

41°15'

41°00'

40°45'

Valley and Ridge

Province

Valley and Ridge

Province

New England

Province

New England

Province

EXPLANATION

Delaware River Basin Commission site

New Jersey Department of Environmental

Protection (NJDEP) Existing Water Quality

site

U.S. Geological Survey site (USGS)

National Water Quality

Assessment

USGS/NJDEP Network

Land use/ Land cover

Agriculture

Barren land

Forest

Urban

Water

Wetlands

Physiographic region boundary

Stream

Upper

Delaware River

Watershed

study area

New

Jersey
Sixty-seven percent of the land in WMA1 is undeveloped (N.J. 

Department of Environmental Protection, 2000). Forested areas 

account for 53.3 percent; reservoirs, lakes, and ponds, 10.3 

percent; wetlands, 3.0 percent; and barren areas, 0.7 percent. 

Nearly 33 percent of the study area is developed; 19.0 percent 

is used for agricultural purposes; and 13.6 percent is urban land 

used for residential, commercial, and industrial purposes. The 

Dunnfield Creek, Vancampens Brook, Flat Brook, and Shimers 

Brook watersheds in the northwestern part of the study area are 

the least developed (84.6-99.9 percent undeveloped land) (fig. 1). 

The largest areas of urban land use are found in the vicinity 

of Lake Hopatcong and Hackettstown in the upper portions of 

the Musconetcong River watershed, near Washington in the 

headwaters of the Pohatcong Creek watershed, near Newton 

Borough in the Paulins Kill watershed, and in the Phillipsburg 

area in the downstream part of the Lopatcong Creek watershed. 

Agricultural land use is most prevalent (30-46 percent of the 

total land area) in the Pophandusing Brook, Delawanna Creek, 

Lopatcong Creek, Pohatcong Creek, and Buckhorn Creek 

subwatersheds. 

Thirty-nine water-quality sites, (table 1) including 18 USGS/

NJDEP cooperative network sites, 15 Delaware River Basin 

Commission (DRBC) sites sampled during 1985-2001, 3 USGS 

National Water-Quality Assessment Program (NAWQA) sites 

sampled in 1997, and 15 NJDEP Existing Water Quality (EWQ) 

sites sampled in 2001 (fig. 1) are located throughout the study 

area. (Three sites are in both the USGS/NJDEP and DRBC 

networks, and nine EWQ sites coincide with sites in the other 

networks.) Sampling sites are located in 12 of the 14 major 

subwatersheds. White Brook, with the smallest subwatershed 

(2.09 mi2), and Stony Brook (4.08 mi2) are the only tributaries to 

the Delaware River in the study area whose drainage areas are 

larger than 2 mi2 for which no water-quality data are available 

for the constituents and properties studied. Thirty sites drain 

watersheds located entirely in one province--18 in the Valley 

and Ridge and 12 in the New England Province. Nine sites drain 

watersheds that include parts of both provinces (fig. 2). Water 

draining from 549 mi2, or 74 percent of the area covered by 

WMA1, flows past the USGS/NJDEP network sites. Water draining 

from 648 mi2, or 87 percent of WMA1, flows past the DRBC sites.

Permitted municipal and industrial point sources discharge 

effluent to streams upstream from sampling sites in the 

Musconetcong River, Paulins Kill, Pequest River, Lopatcong 

Creek, Pohatcong Creek, and Pophandusing Creek watersheds 

(table 1). The Musconetcong River, Paulins Kill, and Pequest River 

receive discharge from 15, 11, and 10 permitted point sources, 

respectively, upstream from the sampling sites. The Lopatcong 

and Pohatcong Creeks and Pophandusing Brook each receive 

discharge from two permitted point sources. Flow data from 

municipal facilities for 1994-99 indicate that the following amount 

of effluent is discharged upstream from sampling sites in each 

watershed: 5.8 ft3/s to the Musconetcong River, 1.7 ft3/s to the 

Paulins Kill, 1.0 ft3/s to Pohatcong Creek, and 0.9 ft3/s to the 

Pequest River.

Methods of Study

Constituents and Properties

Analyses of water samples collected at the 39 sampling sites 

for nine constituents and properties that are considered to be 

important indicators of the quality of water in the Upper Delaware 

River watershed were studied. The constituents and properties 

selected are temperature, pH, dissolved oxygen, dissolved-solids, 

suspended solids, nitrate plus nitrite, un-ionized ammonia, total 

phosphorus, and fecal coliform bacteria. Un-ionized ammonia is 

the component of aqueous ammonia that is most toxic to aquatic 

life (Schornick and Fischel, 1980). Dissolved oxygen is affected 

by the physical, chemical, and biological characteristics of the 

stream, and adequate concentrations promote the health of 

aquatic ecosystems. Dissolved-solids are an important constituent 

to water purveyors and users because costly treatment may 

be required when concentrations are elevated. Levels of fecal 

coliform bacteria are a measure of the sanitary quality of the 

water; when these levels are high, streams may be unsuitable 

for swimming or other uses. Nitrate and nitrite are the oxidized 

forms of nitrogen in the stream. Concentrations greater than 10 

mg/L (milligrams per liter) can cause methemoglobinemia (“bluebaby syndrome”) in infants (Walton, 1951). Nitrogen is a primary 

nutrient for rooted aquatic plants and algae and, therefore, can 

stimulate excessive growth of aquatic vegetation. The pH of water 

is a measure of its acidity or alkalinity. A pH in the range of 6.5 

to 8.5 is considered most conducive to aquatic health. The total 

phosphorus concentration is an important indicator of stream 

condition, as phosphorus, another primary nutrient for aquatic 

plants and algae, can stimulate excessive growth. Suspended 

solids are an important indicator of the presence of nonpointsource contaminants. The primary sources of suspended solids 

in streams are storm runoff, instream erosion, and resuspension 

of sediment. Water temperature affects the chemical and 

biological processes that occur in a stream. Water temperature is 

determined by the amount of sunlight reaching the stream, rainfall, 

air temperature, the amount of ground water discharging to the 

stream, and the presence of thermal point sources.

Data Review and Analysis

All data were reviewed extensively for quality-assurance purposes. 

Water-quality data from each USGS/NJDEP and USGS NAWQA 

site were plotted against streamflow, plotted by season, and 

compared with measured levels of other constituents. The review 

resulted in fewer than 0.1 percent of the values being changed or 

removed from the study database. Some measurements of nitrate 

plus nitrite and phosphorus derived from field-kit determination 

were not included in the statistical analyses. 

Statistical tests were used to summarize and compare data, 

examine changes in water quality over time, and examine 

relations between water quality and land use. Data from each 

network were evaluated with respect to instream reference levels 

based on instream water-quality standards for the State of New 

Jersey. The USGS/NJDEP and DRBC sites for which a sufficient 

number of samples were available were evaluated for (1) trends 

during the study period, (2) variability in water quality with season 

and flow condition, (3) variability among all sites in the study 

area, (4) variability among sites along stream reaches, (5) relation 

between water quality and land use, and (6) comparison with data 

from statewide sampling networks. 

Water samples were categorized by season and by the hydrologic 

condition when they were collected. Samples collected when flow 

was less than the median for the study period are classified as 

low-flow samples; those collected when flow was greater than the 

median are classified as high-flow samples. The period from April 

through October is designated the growing season and the period 

from November through March is designated the non-growing 

season (Ruffner and Bair, 1977).

Statistics including minimum, maximum, median, 25th and 75th 

percentiles, and standard deviation were used to analyze the 

distribution of concentrations, fecal coliform counts, pH values, 

and temperatures in the data set. A percentile is a value that 

indicates the percentage of samples for which the associated 
Figure 3. Boxplots showing distribution of total phosphorus 

concentrations in samples from 21 USGS/NJDEP network 

sites, and median concentrations in all samples from 

Statewide status and Statewide background sites.

measurements are less than or equal to it. The median value is 

the 50th percentile. The analysis of variance and Wilcoxan rank 

sum tests were used to test for significant differences in the 

means of two or more data sets (Helsel and Hirsch, 1992). Median 

values of the nine constituents and properties were evaluated 

with respect to land use at the 12 sites for which 12 or more 

measurements were available by using least-squares regression 

(Ott, 1988). The seasonal Kendall test (Helsel and Hirsch, 1992) 

was used to test data from 1985 through 2000 for trends.

Boxplots, such as the boxplot of total phosphorus concentrations 

shown in figure 3, were used to show the distribution of the central 

50 percent of the data for each site. Streams are shown from left 

to right in downstream order by subwatershed. The horizontal line 

through the middle of the box represents the median value at the 

site, the horizontal line at the top of the box indicates the 75th 

percentile (75 percent of the data are less than this value), and 

the horizontal line at the bottom of the box represents the 25th 

percentile (25 percent of the data are less than this value). The 

median of the total phosphorus concentrations at each study site 

was compared to the median of the medians at all sites, to the 

median at statewide and background sites, and to the New Jersey 

surface-water standard (fig. 3)

Cumulative probability curves (fig. 4) are another tool for analyzing 

the distribution of data at each site. Curves with steep slopes 

indicate a large range in values; curves with a flat slope indicate 

a small range in values. The y-axis spans the range of values 

covering all the samples analyzed. The x-axis represents the 

percentage of time that measurements are below a given value. 

The red horizontal lines represent the instream water-quality 

standard. The intersection of the curve with the red line indicates 

the percentage of the samples from each site for which the 

associated measurement meets the standard.

Comparison to Statewide Water Quality

In general, streamwater quality in the study area compares 

favorably to water quality in streams throughout New Jersey. 

Water-quality data from sites on streams in WMA1 indicate a lower 

median concentration of suspended solids, total phosphorus, 

and nitrate plus nitrite, lower median water temperature, and 

a lower median count of fecal coliform bacteria, but a higher 

median concentration of dissolved oxygen and a higher median 

pH, than data from sites in the USGS/NJDEP statewide network 

of 109 randomly chosen sites on streams across the State. With 

respect to these seven constituents and properties, therefore, 

the quality of streamwater in WMA1 was better than that in the 

State as a whole. Dissolved-solids concentrations were higher, 

most likely because of the bedrock in the area. Dissolved-solids 

concentrations were highest during low flow in the summer and 

are not a result of the application of road salt during winter storms. 

Un-ionized ammonia concentrations were higher in WMA1 than 

at randomly selected sites across New Jersey; however, median 

concentrations were low, less than 0.001 milligrams per liter in 

both data sets.

Water-quality data for the study area were compared with data 

collected at the six USGS/NJDEP network background sites--sites 

draining predominantly undeveloped areas. In general, water 

quality at the statewide background sites is better than the 

water quality in WMA1 (fig. 3). Dissolved oxygen is the only 

constituent whose median value is indicative of better water 

quality in the study area than at statewide background sites. 

Median values for all constituents and properties at sites draining 

predominantly undeveloped areas in the Dunnfield Creek and Flat 

Brook watersheds (except for dissolved-solids in the Flat Brook 

watershed) are statistically equal to or lower than those at sites 

draining undeveloped areas statewide (fig. 3).

Comparison to Water-Quality Criteria

The New Jersey instream water-quality standards (New Jersey 

Department of Environmental Protection, 1998) for some of the 

constituents and properties studied do not apply to instantaneous 

values derived from one sample. The un-ionized ammonia 

standard of 0.02 mg/L (milligrams per liter) for trout sites and 0.05 

mg/L for nontrout sites is for a 24-hour average concentration. 

The standard for fecal coliform bacteria is that the count is to 

exceed neither a geometric mean of 200/100 mL nor 400/100 mL 

in 10 or more percent of the total number of samples collected 

in a 30-day period (New Jersey Department of Environmental 

Protection, 1998). For water temperature, thermal alterations from 

point-source discharges should not raise the ambient stream 

temperature more than 0.6-2.8 °C (degrees Celsius), or to a 

temperature that is higher than the maximum level consistent 

75th percentile

EXPLANATION

CONCENTRATION, IN MILLIGRAMS PER LITER

Dunnfield Creek

Dry Brook

Jacksonburg Creek

Pohatcong Creek

Paulins Kill

Musconetcong River

Pequest River

P

Flat Brook

aulins Kill

1

0.5

0.1

0.05

0.01

0.005

TOTAL PHOSPHORUS

0.03

0.025

0.009

(49)

(24)

(2)

(11)

(77)

(100)

(4)(5)

(9)

(11)

(34)

(23)

(76)

(40)

(42)

(72)

(2)

(34)

(102)

Median (50th percentile)

25th percentile

0.10

Sample size (24)

New Jersey surface-water standard

Median in all samples from U.S. Geological Survey/New

Jersey Department of Environmental Protection

network sites

Median in all samples from statewide status sites

Median in all samples from statewide background sites
with the protection of aquatic life. The instream criteria for these 

constituents were used only as a level of reference for evaluating 

water-quality conditions in the study area. The drinking-water 

standard (New Jersey Department of Environmental Protection, 

1989; Shelton and Lance, 1997) set by USEPA and NJDEP 

for nitrate plus nitrite concentrations (10 mg/L) was used as a 

reference level in the absence of surface-water-quality criteria. 

(A surface-water-quality standard is in effect for nitrate only (New 

Jersey Department of Environmental Protection, 1998).)

The constituents and properties most commonly found to exceed 

instream reference levels at USGS/NJDEP and DRBC sampling 

sites were fecal coliform bacteria (> 400 counts/100 mL (milliliters) 

in 23 percent of samples); total phosphorus (> 0.1 mg/L in 22 

percent of samples); water temperature (>20 °C at trout sites in 

21 percent of samples); and pH (>8.5 or <6.5 in 13 percent of 

samples). At sites in nontrout waters, the percentage of samples 

in which counts of fecal coliform bacteria and total phosphorus 

concentrations did not meet reference levels was 51 and 31 

percent, respectively. All constituents and properties studied 

(except nitrate plus nitrite concentrations) exceeded reference 

levels in at least one sample collected at one or more sites in the 

study area. 

The number of constituents that did not meet reference levels 

was higher at sites on the Musconetcong River and Pohatcong 

Creek than at sites on other streams; values of six of the nine 

constituents and properties exceeded the reference levels in one 

or more samples. Total phosphorus concentrations exceeded 0.1 

mg/L in 80 percent of all samples at Pohatcong Creek at New 

Village (fig. 4). Concentrations exceeded that level in 97 percent 

of samples at low flow, indicating a constant base-flow or point 

source. At other sites, phosphorus concentrations exceeded 

0.1 mg/L in less than 35 percent of the samples. Fecal coliform 

bacteria counts exceeded the 400/100mL reference level in more 

than half the samples at 11 of the 33 sampling sites, including 

the 2 sites on the Pohatcong River and the 2 sites farthest 

downstream on the Musconetcong River. Most exceedences 

Figure 4. Cumulative probability curves for total phosphorus concentrations in samples collected at 12 USGS/

NJDEP network sites during 1985-2000.

0 20 40 60 80 100

0.01

1

0.02

0.03

0.04

0.05

0.07

0.1

0.2

0.3

0.4

0.5

0.7

01442760

0 20 40 60 80 100

0.01

1

0.02

0.03

0.04

0.05

0.07

0.1

0.2

0.3

0.4

0.5

0.7

CONCENTRATION, IN MILLIGRAM PER LITER

01443440

01443500

01445500

01446400

0 20 40 60 80 100

0.01

1

0.02

0.03

0.04

0.05

0.07

0.1

0.2

0.3

0.4

0.5

0.7

01455200

0 20 40 60 80 100

0.01

1

0.02

0.03

0.04

0.05

0.07

0.1

0.2

0.3

0.4

0.5

0.7 01455500

01455801

01456200

01457000

01457400

0 20 40 60 80 100

0.01

1

0.02

0.03

0.04

0.05

0.07

0.1

0.2

0.3

0.4

0.5

0.7

01440000

Flat Brook 

Paulins Kill and

Pequest River 

Musconetcong River 

Dunnfield Creek

Pohatcong Creek

PERCENT OF SAMPLES IN WHICH CONCENTRATION

WAS LESS THAN INDICATED VALUE

PERCENT OF SAMPLES IN WHICH CONCENTRATION

WAS LESS THAN INDICATED VALUE

EXPLANATION

New Jersey surface-water standard (0.1 milligram per liter)

New Jersey surface-water standard for lakes and reservoirs

(0.05 milligram per liter)

Site 01443440 (nontrout waters)

Blue lines indicate sites designated as trout production or 

trout maintenance 
at the USGS/NJDEP sites occurred during low-flow conditions. 

Counts of fecal coliform bacteria exceeded 400/100mL in 82 

percent of the samples collected from the Pohatcong River during 

low flow.

The sites on Dunnfield Creek (station 01442760) and Jacksonburg 

Creek (station 01443550) are the only sites where the pH was 

less than 6.4. The pH of 65 percent of the DRBC samples and 33 

percent of the USGS/NJDEP samples collected at the Dunnfield 

Creek site, and 25 percent of the samples collected at the site 

farthest upstream on Jacksonburg Creek, was less than the 

instream reference level of 6.5. The watersheds upstream from 

both sites are more than 94 percent undeveloped and contain 

no agricultural land. Both sites drain steep, mountainous terrain 

along the Kittatinny Mountain ridge. The bedrock upstream from 

these sites consists of erosion-resistant layers of sandstone 

and siltstone unique in WMA1 to the Kittatinny Mountain and 

Walpack Ridges. Soil pH in this area ranges from extremely acid 

to moderately acid (U.S. Department of Agriculture, 2002), with 

values ranging from 3.5 to 5.5 (Christine Hall, Natural Resource 

Conservation Service, written commun., 2002). At a sampling site 

farther downstream on Jacksonburg Creek, pH ranged from 7.5 

to 8.1 because the area upstream from this site through which the 

stream flows is underlain by limestone bedrock.

Trends in Water Quality

Measurements of chemical constituents and properties were 

sufficient to conduct trend tests at 10 of the 21 USGS/NJDEP 

sites. No significant trend was found for most of the constituents 

and properties at most of the sites; however, some significant 

trends were observed. Concentrations of un-ionized ammonia and 

total phosphorus decreased at some sites on the Musconetcong 

River, Pohatcong Creek, and Paulins Kill. The sites on the 

Musconetcong River and Pohatcong Creek with the highest 

median concentrations are among those where concentrations 

of these constituents decreased. Water temperature decreased 

at the site farthest downstream on both the Musconetcong River 

and Paulins Kill, and pH decreased at a site on the Pequest River. 

Dissolved oxygen concentration increased at Musconetcong River 

at the outlet of Lake Hopatcong, the site with the lowest median 

value. Concentrations of nitrate plus nitrite and dissolved-solids, 

however, increased at some sites on the Musconetcong River and 

Pohatcong Creek. The median concentration of nitrate plus nitrite 

(1.93 mg/L) was highest at Pohatcong Creek, but the highest 

values at the site still were substantially lower than the instream 

reference level. Because the rate of increase was small, upward 

trends in concentrations of nitrate plus nitrite do not appear to be 

an indication that the instream reference level (10 mg/L) will be 

approached. 

Relation of Water Quality to Land Use

Median concentrations of all constituents and properties except 

dissolved oxygen were significantly related to the land use 

upstream from USGS/NJDEP sampling sites. Sampling sites on 

streams draining areas containing more than 78 percent forested 

land (fig. 5) were associated with significantly lower median 

values of six of the nine measures studied and higher median 

concentrations of dissolved oxygen than sites draining areas 

containing less forested land. Median values for fecal coliform 

bacteria, dissolved solids, and total phosphorus were significantly 

higher at agricultural sites than at urban and undeveloped sites. 

Median values for water temperature, pH, nitrate plus nitrite, unionized ammonia, and suspended solids were not significantly 

different at agricultural and urban sites. 

Figure 5. Relation of median concentrations, fecal coliform 

counts, and pH units for samples collected during 1985-2000 

at the USGS/NJDEP network sites to percent of forested 

land use in the watershed. (Six of the nine constituents and 

properties studied increase, and one (dissolved oxygen) 

decreased with a decrease in forested land use.)

Variability of Water Quality in the Study Area

Variability of water quality at a site is related to changes in season 

and (or) flow condition. Values of the following constituents and 

properties were significantly higher in the growing season than in 

the non-growing season at one or more sites: water temperature, 

fecal coliform count, pH, and concentrations of total phosphorus, 

un-ionized ammonia, and dissolved solids. Values of the following 

constituents were significantly higher in the non-growing season 

0

100

50

LAND USE,

IN PERCENT 0.001

1

0.01

0.1

0.00001

0.01

0.0001

0.001

CONCENTRATION, IN MILLIGRAMS PER LITER

10

1,000

20

50

100

200

500

0

10

5

1

5,000

10

100

1,000

MOST PROBABLE 

NUMBER

9

12

10

6

9

8

STANDARD

UNITS

DISSOLVED OXYGEN

TOTAL PHOSPHORUS

UN-IONIZED AMMONIA

DISSOLVED SOLIDS

SUSPENDED SOLIDS

FECAL COLIFORM

pH

r squared =0.36

r squared = 0.69

r squared = 0.67

r squared = 0.57

r squared = 0.48

r squared = 0.55

r squared = 0.53

EXPLANATION

Musconetcong River

Flat Brook

Dunnfield Creek

Paulins Kill

Musconetcong River

Pequest River

Musconetcong River

Pequest River

Musconetcong River

Pequest River

Pohatcong Creek

Paulins Kill

Urban

Agriculture

Barren

Water

Wetland

Forest

Best-fit line

Median value

LAND-USE CATEGORY
than in the growing season at one or more sites: pH, and 

concentrations of dissolved oxygen and nitrate plus nitrite. Values 

of six constituents and properties were significantly higher at 

low flow than at high flow at one or more sites; concentrations of 

dissolved oxygen, suspended solids, and nitrate plus nitrite were 

significantly higher at high flow at some sites.

Water quality varied significantly among sites (fig. 3). Sites on the 

Musconetcong River and Pohatcong Creek were among those 

with the lowest median dissolved oxygen concentration and the 

highest median values of six of the remaining eight constituents 

and properties. Sites on the Pequest River were among those with 

the highest median values for four constituents and properties. In 

contrast, sites on Flat Brook and Dunnfield Creek were associated 

with some of the highest dissolved oxygen concentrations and the 

lowest values of the remaining eight constituents and properties. 

Median values of five constituents and properties were among the 

lowest at the site on Vancampens Brook.

Water quality also varied among the five sampling sites with 

sufficient data for comparison along the Musconetcong River and 

between the two sites sampled along both the Pequest River and 

Paulins Kill. Few significant differences were observed between 

median values for the Pequest River sites at Pequest (upstream 

site) and Belvidere (downstream site), which are approximately 

6 miles apart. Fecal coliform counts were significantly higher 

at Belvidere, and concentrations of suspended solids were 

significantly higher at Pequest. Land use is similar in both 

watersheds, and no municipal point sources discharge to the river 

between the sites. Values of five constituents and properties were 

significantly different between the site at Balesville (the farthest 

upstream) and the site at Blairstown (the farthest downstream) 

on the Paulins Kill, which are approximately 15 miles apart. The 

Balesville site is associated with higher concentrations of total 

phosphorus, dissolved solids, and nitrate plus nitrite, and higher 

counts of fecal coliform bacteria than the Blairstown site. The 

median pH, however, is higher at Blairstown than at Balesville. 

Higher percentages of agricultural and urban land and a larger 

percentage of instream flow from municipal point sources 

upstream from Balesville may contribute to these differences.

Sites along the Musconetcong River were among those with 

both the highest and lowest values of pH and concentrations 

of nitrate plus nitrite, total phosphorus, suspended solids, and 

dissolved oxygen in the study area (fig. 4). pH and concentrations 

of dissolved oxygen, nitrate plus nitrite, and suspended solids 

were lower at the upstream sites than at the downstream sites. 

Total phosphorus concentrations were among the lowest on the 

Musconetcong River at the outlet of Lake Hopatcong (station 

01455500) and at Bloomsbury (station 01457000), and among the 

highest at Beattystown (station 01456200) (fig. 1). The increase 

in median total phosphorus concentration between the outlet of 

Lake Hopatcong and Beattystown may result from the presence 

of point-source discharges between Bloomsburg and Beattystown 

and the proximity of the Beattystown site to the urban area in and 

around Hackettstown. 

Median concentrations of dissolved solids and nitrate plus 

nitrite and median counts of fecal coliform bacteria increased 

progressively and significantly from upstream to downstream 

along the Musconetcong River. Suspended solids concentrations 

for the two upstream sites are not available; however, median 

concentrations at the other sites increased progressively 

with distance downstream, doubling from the Beattystown to 

Reigelsville sites. Median pH values were significantly lower 

at the two sites in the upper part of the watershed than at the 

three sites farthest downstream. Concentrations of un-ionized 

ammonia and total phosphorus were equally low at the upstream 

Contact for additional information:

U.S. Geological Survey

Water Resources Division

810 Bear Tavern Road, Suite 206

West Trenton, NJ 08628

site and the Bloomsbury site; concentrations at the other three 

sites were significantly higher. Significant increases in constituent 

concentrations and pH from the upstream to the downstream 

sampling sites may result in part from the presence of permitted 

point sources and higher percentages of agricultural land in the 

lower parts of the watershed.

 —Robert G. Reiser

References Cited

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resources: New York, Elsevier Science Publishing Company, 

Inc., 522 p.

New Jersey Department of Environmental Protection, 1989, Safe 

Drinking Water Act: New Jersey Administrative Code, 

7:10-1 through 16.12.

_____1998, Surface water quality standards: New Jersey 

Administrative Code 7:9B: Trenton, N.J., New Jersey 

Department of Environmental Protection, April 1998, 122 p.

______2000, Land use/land cover and impervious surfaces 

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Department of Environmental Protection, Bureau of 

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2000, on the World Wide Web at URL http://www.state.nj.us/

dep/gis/digidownload/zips/lulc95/w011u95.zip) 

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Department of Environmental Protection and Energy, New 

Jersey Geological Survey, scale 1:1,000,000.

Ott, L., 1988, An introduction to statistical methods and data 

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Ruffner, J.A., and Bair, F.E., eds., 1977, The weather almanac 

(2d ed.): New York, Avon Books, 35 p.

Schornick, J.C., and Fischel, D.K., 1980, Effects of storm runoff 

on water quality in the Mill Creek drainage basin, Willingboro, 

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Investigations Report 80-98, 111 p.

Shelton, T.B., and Lance, S.E., 1997, Interpreting drinking water 

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Brunswick, New Jersey, Rutgers Cooperative Extension, 63 p.

U.S. Department of Agriculture, 2002, Official soil series 

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Oquaga soil series, Natural Resource Conservation Service, 

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Walton, G., 1951, Survey of literature relating to infant 

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