Delaware River Water Quality

^ristol to Marcus Hook

Pennsylvania

August 1949 to December 1963

r«» W. B. KEIGHTON 

ONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1809-O

^repared in cooperation with the 

:ity of Philadelphia

'.JNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1965
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretory

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 - Price 25 cents (paper cover)
CONTENTS

Page

Abstract_______________________________________________________ 01

Introduction. _____________________________________________________ 1

Purpose and scope_____________________________________________ 4

Previous investigations and acknowledgments.____________________ 4

Some basic physical and hydrologic facts______.______________________ 5

Graphic summaries of water-quality facts__________________________ 9

Water temperature____________________________________________ 9

Hydrogen-ion concentration (pH)______________________________ 10

Dissolved-solids concentration_________________________________ 10

Composition of dissolved solids__________________________________ 19

Chloride___________________________________-_ 24

Dissolved oxygen._____________________________________________ 27

Suspended sediment.__________________________________________ 30

Tabular summaries of water-quality characteristics ____________________ 36

Local variations in water-quality patterns___________________-__--___- 40

Summary and conclusions._________________________________________ 53

Selected references.________________________________________________ 57

ILLUSTRATIONS

Page 

FIGUBE 1. Map showing location of sampling stations.____________ 03

2-29. Graphs showing:

2. Annual water discharge of the Delaware River at

Trenton, N.J____________________ 5

3. Monthly water discharge of the Delaware River

at Trenton, N.J____________________ 7

4. Annual water temperature.___________________ 10

5. Frequency of water temperatures._____________ 11

6. Distribution of water temperatures each month. _ 12

7. Annual pH values of water..__________________ 14

8. Frequency of pH values._____________________ 15

9. Relation between electrical conductivity and

dissolved solids (0-200 ppm)________________ 16

10. Relation between electrical conductivity and

dissolved solids (200-4,000 ppm)____.__ 17

11. Annual mean conductivities.__________________ 18

12. Annual maximum conductivities.______________ 19

13. Frequency of dissolved-solids concentrations _ 20

14. Monthly mean conductivities and water discharge,

1954__-_-_.______________._...__-_._ 21

15. Mean monthly conductivities._________________ 22

m
IV CONTENTS

FIGURE 1. 16. Relation between concentration and composition Page 

of dissolved solids_-----__------_------_-__- O23

17. Typical composition of dissolved solids, by percentage of chemical equivalents._____________ 24

18. Annual mean chloride concentrations. __________ 25

19. Annual maximum chloride concentrations. ______ 26

20. Frequency of chloride concentrations, 1930-61___ 28

21. Frequency of chloride concentrations, 1950-62. __ 29

22. Mean monthly chloride concentrations....______ 31

23. Annual mean dissolved-oxygen concentrations. _ _ 32

24. Annual minimum dissolved-oxygen concentrations. ________-----_-------_------------__ 32

25. Frequency of dissolved-oxygen concentrations. _ _ 33

26. Mean monthly dissolved oxygen concentrations. . 34

27. Dissolved-oxygen concentrations in four periods

of the year._______________________________ 35

28. Annual suspended-sediment concentrations. _____ 36

29. Mean monthly suspended-sediment concentrations. _____________-__----------____-_--__ 36

TABLES

Page

TABLE 1. Distance relations and drainage area of sampling stations in 

Delaware estuary, Burlington-Bristol Bridge to Marcus Hook 

Pa________________________________________________ O2

2. Monthly and annual mean water discharge, in cubic feet per

second, Delaware River at Trenton, N.J., 1945-63__ _____ 6

3. Time required to flush Delaware River upstream from sampling

locations, at various discharge rates.____________________ 7

4. "Age" of river water at mean tidal range_________________ 9

5. Comparison of ratios of dissolved solids in Delaware River at 

Trenton and Marcus Hook with ratios of dissolved solids in 

ocean water._________________________________________ 22

6. Number of days each year in which selected chloride concentrations were exceeded for a salt-water invasion, Delaware 

River at Bridesburg, Chester, and Marcus Hook, Pa., and 

average June to October discharge at Trenton, N.J., for each 

year_______________________________________ 27

7. Number of days dissolved-oxygen concentration was less than 

1 and 3 ppm at three dissolved-oxygen recorders in Delaware 

River, March 1961-December 1963__._--____________ 30

8. Physical description of sampling locations._________________ 37

9. Range and frequency distribution of selected percentile groups

of water-quality parameters, Delaware River, 1949-63_____ 41

10. Annual maximum, mean, and minimum of water-quality

parameters, Delaware River, 1950-63-------------------- 44

11. Monthly maximum, mean, and minimum of water-quality

parameters, Delaware River, 1949-63___._-_____-____-_ 48
CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

DELAWARE RIVER WATER QUALITY, BRISTOL TO

MARCUS HOOK, PENNSYLVANIA, AUGUST 1949 TO

DECEMBER 1963

By W. B. KEIGHTON

ABSTRACT

During the 14-year period from August 1949 to July 1963, the U.S. Geological Survey, in cooperation with the city of Philadelphia, collected samples of 

river water once each month in the 43-mile reach of the Delaware River from 

Bristol to Marcus Hook, Pa., and daily at Trenton, 10 miles upstream from 

Bristol, This part of the Delaware is an estuary into which salt water is 

brought by tides; fresh water flows into the estuary at Trenton, N.J., and 

farther downstream from the Schuylkill River and other tributaries of the 

Delaware.

In March, April, and May, when fresh-water flow is high, the average concentration of dissolved solids in the water at Bristol was 76 ppm (parts per 

million), and at Marcus Hook 112 ppm. In August and September, streamflow 

is lower, and the average concentrations of dissolved solids increased to 117 

ppm at Bristol and 804 ppm at Marcus Hook. Major salinity invasions of the 

Delaware River occurred in 1949, 1953, 1954, 1957, and 1963. In each of these 

years the fresh-water flow into the tidal river at Trenton was low during the 

period from July to October. The greatest dissolved-solids concentrations in 

these monthly samples were 160 ppm at Bristol and 4,000 ppm at Marcus Hook.

At times the dissolved-oxygen concentration of the river water has become 

dangerously low, especially in that reach of the river between Wharton Street 

and League Island. At the Benjamin Franklin Bridge, one-third of the samples of river water were less than 30 percent saturated with oxygen; however, 

no trend, either for better or for worse, was apparent during the 14-year period.

It is useful now to summarize these monthly analyses for the period 1949-63 

even though a much more detailed description of water quality in this reach of 

the estuary will soon become available through the use of recording instruments. This period includes a range of conditions and exhibits the extent to 

which water-quality parameters varied with change in hydrologic and environmental conditions. This compendium of water-quality data is useful as an 

explicit statement of water quality during the 14-year period and is valuable 

for directing attention to water-quality problems, for selecting instrument sites, 

and for making comparative studies with the more detailed information which 

is already being obtained with the aid of recording instruments.

INTRODUCTION

The Delaware River from Trenton to the ocean is an estuary in 

which saline water moves down and upstream twice daily with the 

ebb and flood of the tide and mixes with the fresh water that flows

Ol
O2 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

into the estuary from the head of tide at Trenton and from the 

Schuylkill River and other tributaries below the head of tide. The 

changes in chemical quality of the river water are of interest to those 

who would understand water quality in this or any estuary. Furthermore, these changes are important because that part of the estuary described in this report is within a populous and industrialized 

region that depends upon the estuary for a source of water for 

household and industrial use and also makes use of the estuary to 

dilute and carry away its wastes. Because the estuary is a major 

source of water in this region, a knowledge of water quality in the 

estuary is of interest to many municipalities and industries, as well 

as to individual citizens, sportsmen, and conservation groups.

The U.S. Geological Survey has collected monthly water samples 

in the Delaware estuary since August 1949 at eight sampling stations 

from Bristol, Pa., to the Pennsylvania-Delaware State line at Marcus 

Hook, Pa. The location of these stations is shown in figure 1, and

TABLE 1. Distance relations and drainage area of sampling stations in Delaware 

estuary, Burlington-Bristol Bridge to Marcus Hook, Pa.

1

2 

3 

4 

5 

6 

7 

8

Station i

Bristol (Pa.) -Burlington (N.J.) Bridge.--. .

Torresdale, Philadelphia, Pa ______ _

Benjamin Franklin Bridge. ______ _ _ _____

Wharton Street, Philadelphia, Pa___ _ _ __

League Island, Philadelphia, Pa. _____

Eddystone, Pa__ ____ _ -.________ _____

Marcus Hook, Pa. _ _.__ ________________

Drainage 

area, in 

square 

miles

7,160 

7,781 

7,935 

7,993 

7,998 

8,072 

10, 190 

10, 370

River distance, in miles, 

of midchannel stations

Between 

stations

8.1 

8.0 

1.8 

1.5 

5.4 

8.7 

6.0

From Trenton, N.J.

15.2 

23.3 

31.3 

33.1 

34.6 

40.0 

48.7 

54.7

i For location of stations, see fig. 1.

the stations are listed in table 1. In addition, a daily sampling station has been operated, above the head of tide, on the Delaware River 

at Trenton, N.J., since 1944. The four upstream stations were sampled on one day, and the four downstream stations on the following 

day, or vice versa. Sampling trips were scheduled without regard to 

possible tidal, climatic, or other environmental conditions. Most of 

the trips to date have been completed within the first 10 days of each 

month. At times, owing to inclement winter weather, it was hazardous to sample by boat. For this reason, actual data are occasionally 

missing for a winter month; however, in compiling the summaries 

of data in this report such missing data have been estimated empirically from long-term information.
±=^

Burlington-Bristol 

Bridge station

y :

Lehigh Avenue 

station ,>i^7~-v-3;

Frankl 

Bridge station 5)H Ca-rh^en- e

Wharton

6) ) I station

,§ Marcus Hoofc 

/1 station

DEL.

FIGURE 1. Location of water-quality sampling stations along Delaware estuary, Trenton, N.J., to

Marcus Hook, Pa. o

co
O4 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

PURPOSE AND SCOPE

In the 14-year period from August 1949 to December 1963, many 

analytical data were collected describing the chemical and physical 

quality of water in the Delaware estuary between Bristol and Marcus 

Hook. Most of these analyses have already been published in annual 

reports of the U.S. Geological Survey. To refer to these data, it is 

necessary, however, to consult more than a dozen publications; and 

to comprehend the meaning of the many analyses, it is necessary to 

compare water quality at eight sampling locations for 14 years and 

for the 12 months of each year.

This report presents, in summary form, the water-quality facts 

discovered at these eight sampling stations during the period August 

1949 to December 1963. It has been written to serve as a reference 

book of the important facts concerning the water quality of the Delaware River from Bristol to Marcus Hook and presents a historical 

record of the variations in water quality without analyzing their 

causes. It does not record the basic chemical analyses, water temperatures, or suspended sediment analyses which have already been 

published but instead summarizes, plots, and compares the basic 

data in order to facilitate comprehension of them. Water-quality 

facts are presented in two complementary ways: on pages O9-O36 

the salient features are shown graphically; on pages O36-O51 the 

data are summarized in tabular form for each of the eight sampling 

stations. In both the graphic and the tabular section, I have tried 

to distill the analyses to obtain the essence.

It is hoped that this compendium will facilitate the task of those 

who need to know the quality of water in the estuary, or who desire 

to study the factors that influence the quality of the water and that 

cause the variations observed. It should also be useful in directing 

attention to water-quality problems and in selecting future sites for 

instruments and observations.

PREVIOUS INVESTIGATIONS AND ACKNOWLEDGMENTS

Analyses of water samples collected from August 1949 to December 

1952 are reported and interpreted in "Chemical Characteristics of 

Delaware River Water, Trenton, New Jersey, to Marcus Hook, 

Pennsylvania" (Durfor and Keighton, 1954). Since 1952 the water 

analyses have been published in the annual Geological Survey WaterSupply Paper series entitled "Quality of Surface Waters of the United 

States." These papers are listed below:

WaterSupply 

Year Paper

1957------------------------- 1520

_.._--.-__--__--------- 1571

___-____---_-_--------- 1641

-..__--____------------ 1742

Year

WaterSupply 

Paper

------ 1250

-__.__ 1290

-__--- 1350

-___-. 1400

------ 1450
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK O5

In addition to these compilations of water-quality data, three 

recent publications of the Geological Survey have reported on interpretations of these data. Cohen and McCarthy (1962) in "Salinity 

of the Delaware Estuary" discuss the environmental variables affecting salinity in the estuary. Durfor and Anderson (1963) in a report 

describing the chemical character of streams in Pennsylvania briefly 

discuss water quality in the estuary. A third report is a comprehensive discussion of the quality of water entering the estuary at Trenton "Quality of Delaware Kiver Water at Trenton, New Jersey" 

by McCarthy and Keighton (1964).

These investigations of the chemical quality of the Delaware estuary from 1949 to 1963 have been conducted by the Geological Survey, 

in cooperation with the city of Philadelphia Water Department, 

Samuel S. Baxter, commissioner. They were under the general supervision of W. F. White, district chemist, 1948-52, and N. H. Beamer, 

district chemist from 1952 to the present. The author wishes to express his debt to Leo T. McCarthy, Jr., and Frederick L. Schaefer 

for compiling the tables and preparing the illustrations which are 

the backbone of this report.

SOME BASIC PHYSICAL AND HYDROLOGIC FACTS

The Delaware estuary begins at the head of tide at Trenton, N.J. 

Approximately 1 mile upstream from the head of tide, the U.S. 

Geological Survey maintains a stream-gaging station that has been 

in continuous operation since 1912. Upstream from this gage the 

Delaware Kiver has a drainage area of 6,780 square miles, which is 

about 95 percent of the drainage area at Burlington-Bristol Bridge 

but only about 65 percent of the drainage area at Marcus Hook. The 

seasonal variations in water discharge of the river at Trenton have 

a direct influence on the chemical, physical, and sanitary quality of 

the Delaware estuary. To aid in the interpretation of the waterquality data presented in this report, the annual mean discharges and 

the monthly mean discharges at Trenton, N.J., for 1945-63 are presented in table 2 and plotted in figures 2 and 3.

20,000

3 a: 10,000

~ 1950 51 52 53 54 55 56 57 58 59 1960 61 62 1963

FIGURE 2. Annual mean water discharge of the Delaware River at Trenton, N.J.,

1950-63. 

770-402 0-^65 2
I

3-

« 

s

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enOOOCOOOOOOO

COrfk.H-MentOtOH-'OOtOenOenOJCOtOMtO 

COOCOCOCO)->coeni->cOtOtO»t^enOOtOCOtOOO

h-QOenCOOJOJOH-'MOOOOh-'COMtOtOCOOOOO

tOh-OCOh-'Ot-'i^cOtOCOO^H-'OtOMOen

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a

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tO

jsS^jsSjvljXijXiJxS^njXijNSjNS^CO^njMjNSjMCO^enjM 

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H-> H-1 tO H-1 1 tO H-1 H- ' H-1

OOOCOtOCOH-'COH-'OJOOO 

tOOS»^tOOOOOCOCOMOs 

enOCOh-OOentOOOOJ

COtOOJtO^MO 

enenOSOOeni-> 

OOH-tOOOO

H-i H-i H- H-1 tO H- ' tO H* H-1 H-1

tOCOCOOrfk.tOOOh-'MH-'OOh-'enOCOMOOJCO

^H->coi->ooocoMit^i->cococoen^^aco»^.o

H-OOrf*.OOenOOtOOOOOOOOOOOO

anx anx ox SKOixnamxKoa 9Q
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK 07

t_j 25,000

LJ 

U.

5 20,000

zz

lilm 

OC/5

10,000

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

FIGURE 3. Mean monthly water discharge of the Delaware River at Trenton,

1949-63.

Fresh water flowing into the estuary both dilutes salt water and 

tends to flush it downstream. For example, a discharge of 6,000 cfs 

(cubic feet per second) for 1 day is 5.18 X 10s cubic feet per day. 

The volume of water (at midtide) in the river between Trenton and 

Marcus Hook is 170 X 10s cubic feet. On this basis it is estimated 

that 33 days (170/5.18) would be required to flush the river to Marcus Hook. The results of such calculations for several discharge 

rates are given in table 3; however, fresh water also dilutes salt 

water by tidal mixing, so that the river is generally freshened more 

rapidly than indicated in the table. When the fresh-water flow is 

very low, salt water may advance upstream in spite of the freshwater discharged. ,

TABLE 3. Time required to flush Delaware River upstream from sampling locatwns,

at various discharge rates

Water discharge at Trenton, Flushing time, in days, from Trenton to station indicated l

JN.J.

(cfa)

6,000.___ ___ ______

10,000_____ ___ ____

40,000---__-. _ ____

l

3.2

1.9

.5

2

6.0

3.6

.9

3

10

6.2

1.6

4

11

6.8

1.7

5

12

7.4

1.9

6

17

10

2.5

7

25

15

3.8

8

33

20

4.9

1 For location of stations 1-8, see fig. 1.

The average concentration of dissolved solids in water of the 

Delaware River at Trenton from 1945 to 1961 was 86 ppm and 

ranged from 57 to 126 ppm 90 percent of the time. In March, April, 

and May the median concentration of dissolved solids was 66 ppm, 

and in August and September 107 ppm. The dissolved solids aver-
08 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

aged, in terms of equivalents, 28 percent calcium, 14 percent magnesium, 8 percent sodium plus potassium, 43 percent bicarbonate plus 

sulfate, 5 percent chloride, and 2 percent nitrate (McCarthy and 

Keighton, 1964).

Other tributaries also contribute iresh water to the estuary and 

thereby have some influence on water quality. Of these, the principal tributary is the Schuylkill Kiver, which flows into the Delaware 

Kiver close to, but downstream from, station 6 League Island 

(fig. 1). The Schuylkill River may be expected to exert some influence on water quality downstream from its confluence, at Chester, 

Eddystone (sta. 7), and Marcus Hook (sta. 8). On a flood tide, 

water from the Schuylkill River may flow upstream in the Delaware 

River and dilute the water at League Island (sta. 6).

A gaging station has been maintained since 1931 on the Schuylkill 

River 8.4 miles upstream from the mouth and above tidal influences; 

the monthly and yearly mean discharges are reported annually in 

U.S. Geological Survey publications. The quantity of fresh water 

from the Schuylkill River flowing into the Delaware River each year 

is generally no more than one-quarter of the fresh-water inflow into 

the Delaware River at Trenton, N.J.; furthermore, the fresh water 

discharged from the Schuylkill River is mixed with a tidal flow 

many times as large.

An additional factor in the downstream movement of fresh water 

is the mixing effect of the twice daily ebbing and flooding of the tide. 

Ketchum (1951a, b) devised a method of calculating the time required for water to move from one part of a tidal estuary to another 

downstream location, taking into consideration the tidal mixing. In 

1952 the author applied Ketchum's method to calculate the time of 

travel of a volume element of water from Trenton to several downstream locations. For example, at mean tidal range and a water 

discharge of 6,000 cfs at Trenton, N.J., calculations according to 

Ketchum's method show that 14.5 days are required for water to 

travel from Trenton to Marcus Hook. The water contributed by the 

Schuylkill River was included in these calculations. The "age" of 

fresh water at several locations, as calculated by Ketchum's method, 

is given in table 4. At a discharge of 3,000 cfs at Trenton, fresh 

water or a slug of pollution requires 6.6 days (17.6-11.0) at mean 

tidal range to travel from Benjamin Franklin Bridge to Marcus 

Hook. This flushing time is more rapid than that represented in 

table 3.
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK 09

TABLE 4. "Age" of river water at mean tidal range 

[Calculated by the method of B. H. Ketchum]

Water discharge at Trenton, N.J. 

(cfs)

3,000_ __________________________________

6,000 __ __._._............_...____..__._

12,000. --_ __________________ _-_____

"Age" of river water, in days, from Trenton 

to station specified >

BurlingtonBristol Bridge

5.8 

4.2 

2.7

Benjamin 

Franklin 

Bridge

11.0 

8.6 

6.3

Marcus Hook

17.6 

14.5 

11.5

1 When the tidal range is a foot greater than the mean range, the "age" of the water at Marcus Hook is 

1-2 days less; when the tidal range is a foot less than the mean, the "age" is 1-4 days greater.

GRAPHIC SUMMARIES OF WATER-QUALITY FACTS

The conspicuous variations in water quality in the river from 

Bristol to Marcus Hook, over the period from 1950 to 1963, are presented graphically in this section. Generally, the water-quality characteristics are not plotted for all eight sampling locations, but only 

for enough of them so that the characteristics at the other locations 

may be estimated by interpolation.

Water-quality data are summarized on pages O36-O51, in tables 

which give an additional quantitative view of the variations in water 

quality. For example, the maximum, minimum, and mean values 

are given for several water-quality characteristics at each of the 

eight stations for the total period and for each month of the year. 

In addition, frequency distributions are given for several characteristics. Thus, the graphic and tabular presentation of the qualityof-water facts both complement and supplement each other.

WATER TEMPERATURE

The annual mean water temperatures varied from 55° to 62°F 

(fig. 4) in the reach, the mean temperature at Marcus Hook being 

about 2°F warmer than at Bristol. The maximum water temperature recorded in any year was 86°F, and the minimum temperature 

33 °F. The frequency with which various water temperatures occurred is plotted in figure 5. For example, the median temperature 

was between 57° and 60°F for the eight stations between Bristol and 

Marcus Hook; 10 percent of the samples had temperatures of 82°F 

or greater; and about one-third of the samples had temperatures 

exceeding 67° F. The distribution of water temperatures is shown 

for each month in figure 6. Water temperatures are coldest in January, February, and March and warmest in July and August. The
O10 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES 

90

z 80

UJ 

QL

I

"70

60

S 50

40

Maximum, 

Station 8

Mean, 

Station 8-

Mean, 

Station 1

Minimum, 

^Station 8

30

1950 51 52 53 54 55 56 57 58 59 1960 61 62 1963

FIGURE 4. Annual mean water temperatures, Delaware River at Bristol, 

Pa. (sta. 1) and Marcus Hook (sta. 8), and annual maximum and 

minimum temperature at Marcus Hook, 1950-63.

greatest variability or range in temperatures from year to year is 

in June, September, October, and November.

HYDROGEN-ION CONCENTRATION (pH)

Hydrogen-ion concentration is expressed in pH units. A water 

having a pH of 7.0 is termed "neutral"; pH values greater than 7.0 

indicate alkalinity; and those less than 7.0, acidity. Water in the 

Delaware River between Bristol and Marcus Hook varies from 

slightly basic to slightly acidic. The pH decreases slightly as the 

water flows downstream (figs. 7 and 8). From Burlington-Bristol 

Bridge to Torresdale, the median pH is 6.9; from Lehigh Avenue 

to League Island, 6.6; and from Eddystone to Marcus Hook, 6.5. 

More than half of the pH values at all locations are within 0.2 pH 

units of these medians. There is no evidence of seasonal change 

in pH.

DISSOLVED-SOLTDS CONCENTRATION

Because most of the substances dissolved in the water of the Delaware River estuary are ionized salts, the water conducts electricity. 

The specific electrical conductance of the water, therefore, is a measure of the dissolved-solids concentration. As the analytical determi-
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK Oil

85

80

75

70

65

? 60

55

50

45

40 -

35

\\

Temperature, 

all stations

> 10 20 30 40 50 60 70 80 90 95 

PERCENT OF SAMPLES IN WHICH THE TEMPERATURES 

INDICATED WERE EQUALED OR EXCEEDED

FIGURE 5. Frequency of any given water temperature in 

Delaware River between Bristol and Marcus Hook, 1950-62.
5?

o

d

3. 

cr

c

e+o'

D

PERCENTAGE OF TEMPERATURES OBSER

> i\} co £> ui 

oooooo 
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK O13

I I I I l I

I I I I I I I I I I I I 

September

l l l i i l i i i l l l l l l l i l i i i l i l l l l i

I I I I I I I I I I

I I I I I I I I I I I I I I 

November

l l I l I l I l I I I I l l l l I I l I I I I l I I I l 

December

i i l i T i ii i^ i i in i i i i i i i i i r i r i r

30 34 38 42 46 50 54 58 62 66 70 74 78 82 86 

WATER TEMPERATURE, IN DEGREES FAHRENHEIT

B 

in Delaware River, Bristol to Marcus Hook, 1950-62.

770-402 O 65 3
O14 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

z

I 7-0

z

6.5

6.0

T I I I I I 1 I I I I T

1950 51 52 53 54 55 56 57 58 59 1960 61 62 1963

FIGURE 7. Annual median pH values of water in Delaware River at Bristol 

(sta. 1), Benjamin Franklin Bridge (sta. 4), and Marcus Hook (sta. 8), 

1950-63.

nation of dissolved solids is more expensive than the measurement of 

electrical conductivity, specific conductance is often available when 

the dissolved-solids concentrations are not. If specific conductance 

is the only data available, the dissolved-solids concentration may be 

estimated from it. Figures 9 and 10 are useful for making such 

estimates. In the range from 200 to 2,500 ppm dissolved solids, the 

concentration is directly proportional to the specific conductance. 

From 2,500 to 4,500 ppm the concentration can be estimated from 

the plotted X's.

The yearly variations in mean specific conductance are shown in 

figure 11, in which conductivity is plotted on a logarithmic scale. 

The annual mean conductivity at Bristol-Burlington Bridge varied 

from 135 to 186 micromhos (86-113 ppm dissolved solids), and at 

Marcus Hook from 228 to 2,330 micromhos (135-1,400 ppm dissolved 

solids). The maximum specific conductance for each year at six of 

the stations is plotted in figure 12. During the period 1950-63 the 

maximum specific conductance ranged from 167 to 266 micromhos 

at Bristol-Burlington Bridge (105-160 ppm dissolved solids) and 

from 370 to 6,120 micromhos (220-4,000 ppm dissolved solids) at 

Marcus Hook.

The frequencies of various concentrations of dissolved solids are 

plotted in figure 13. These concentrations have been estimated from 

the frequency of specific conductances.
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK 015

7.4

7.2

7.0

6.8

6.6

LU

o 

86.4

6.2

6.0

5.8

5.6

\

10 20 30 40 50 60 70 80 90

PERCENT OF SAMPLES IN WHICH THE pH VALUES

INDICATED WERE EQUALED OR EXCEEDED

95 98

FIGURE 8. Frequency of given pH values in Delaware River between Bristol 

and Marcus Hook, 1950-62. See figure 1 for location of stations.

In general, the greater the discharge of fresh water into the estuary, the lower is the specific conductance, and the lower the dissolved 

solids. If the fresh-water flow into the estuary at Trenton is less 

than 4,000 cfs for 30-60 days, the dissolved solids at Marcus Hook 

generally increases. When dissolved solids are high, an abrupt increase in streamflow, even for a few days duration, is likely to flush 

the salty water downstream. After an increase in fresh-water dis-
O16 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNTIED STATES

320

300

280

260

o

240

<220

I 

200

-180

0160 

I

8co 120

100

80

60

40,

I I I I

5 =dissolved solids, in ppm 

K = specific conductance, 

in micromhos at 25°C

20 40 60 80 100 120 140 160 

DISSOLVED SOLIDS, IN PARTS PER MILLION

180 200

FIGURE 9. Relation between electrical conductivity and dissolved solids 

(below 200 ppm) in Delaware River between Bristol and Marcus Hook, 

from Durfor and Keighton (1954).

charge, the salinity is reduced first in the upstream section of the 

river, then progressively downstream, if the increased fresh-water 

discharge persists. If the fresh-water flow decreases, the salinity 

increase first takes place far downstream below Marcus Hook and
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK 017

6500

6000

5500

5000

4500

4000

3500

3000

02500

2000

1500

1000

500

I I I T I T

S=dissolved solids, in ppm 

K=specific conductance, 

in micromhos at 25°C

500 1000 1500 2000 2500 3000 3500 

DISSOLVED SOLIDS, IN PARTS PER MILLION

4000 4500

FIGURE 10. Relation between electrical conductivity and dissolved solids 

(200-4,000 ppm) in Delaware River between Bristol and Marcus Hook, 

1950-62.

then moves up river. Other factors, including wind direction and 

intensity, sea level, barometric pressure, and tidal range also affect 

the salinity of the water in the Delaware estuary; therefore, it is 

not possible to predict reliably the specific conductance of the water 

from the magnitude of the fresh-water discharge alone.
I I I I I I I I

100

1950 51 52 53 54 55 56 57 59 1960 61 62 1963

FIGUBE 11. Annual mean conductivities of water in Delaware River between Bristol and Marcus Hook, 

1950-63. See figure 1 for location of stations 1, 4, 6, 7, and 8.

o( >

oo

B

1

3
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK 019

6000

04000

02000

O 

<r 

o

^ 1000 

~ 800

600

400

200

100

I I I I

1950 51 52 53 54 55 56 57 58 59 1960 61 62 1963

FIGURE 12. Annual maximum conductivities of water in Delaware River 

between Bristol and Marcus Hook, 1950-63. See figure 1 for location 

of stations 1, 3, 6, 7, and 8.

The specific conductance decreases after a substantial increase in 

fresh-water discharge and increases after a sufficient reduction in 

fresh-water discharge. The gross effect of streamflow on salinity is 

evident in figure 14; in this figure the specific conductance at Marcus 

Hook and at Benjamin Franklin Bridge, and the fresh-water discharge at Trenton are plotted for each month of 1954. The mean 

monthly conductivity during 1949-63 for several locations is plotted 

in figure 15. Conductivity and dissolved solids are lowest in March, 

April, and May months in which the fresh-water discharge is generally large and highest in August to November.

COMPOSITION OF DISSOLVED SOLIDS

Composition of dissolved solids in the lower part of the estuary 

changes with concentration. Higher concentrations are generally 

the result of the sea water mixing with river water, and consequently, 

as the dissolved solids increase in concentration, the proportion of 

the several ions founds in the estuary water trends toward the proportion found in sea water. Thus, at higher concentrations sodium 

and chloride ions supplant the calcium bicarbonate and sulfate ions,
O20 CONTRIBUTIONS TO THE HYDROLOGY OP THE UNITED STATES

2000

.1000

I

S 800

£j 600

co 500

< 400

c^ 300 

g

H*> Ul

CO

o

100

80

60

50

\

\

\

\

10 20 30 40 50 60 70 80 90 95

PERCENT OF SAMPLES IN WHICH DISSOLVED SOLIDS

EQUALED OR EXCEEDED THAT SHOWN

98 99

FIGURE 13. Frequency of various dissolved-solids concentrations in Delaware 

River between Bristol and Marcus Hook, 1950-62. See figure 1 for location 

of stations 1, 4, 6, 7, and 8.

which predominate at lower concentrations. This phenomenon is 

illustrated in figure 16. Compared to the water entering the estuary 

at Trenton, water in the estuary has less bicarbonate and more 

chloride at all concentrations. Estuary water is compared with the 

fresh water at Trenton in figure 17, the comparison being based on 

the chemical equivalents of each ion. The water at Trenton is a 

calcium bicarbonate-type. In the estuary the proportion of bicarbonate decreases and sulfate increases so that, at low concentrations, 

the estuary water can be described as a calcium bicarbonate-sulfate 

type. At higher concentrations the estuary water becomes a sodium 

chloride water, similar to ocean water.

Because they are related to specific conductance, dissolved-solids 

concentrations are also related to streamflow. Dissolved solids are
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK 021

\ Discharge at Trenton 

\

V

100

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

FIGURE 14. Monthly mean conductivity of water in Delaware River at Benjamin 

Franklin Bridge (sta. 4) and Marcus Hook (sta. 8), and the mean monthly 

water discharge at Trenton, 1954.

brought into the estuary largely in the river water entering at the 

head of the tide at Trenton. In March, April, and May the river 

water at Trenton contains 50-90 ppm of dissolved solids most of the 

time, whereas the concentration at Marcus Hook during these months 

averages from 100 to 125 ppm. In August and September, when the 

dissolved-solids concentration at Trenton is generally 70-145 ppm, 

the concentration at Marcus Hook averages about 800 ppm; however, the greatest quantities of dissolved solids are carried by the 

river at Trenton in March and April, when the streamflow is high, 

and lesser quantities are transported in August and September, when 

the rate of flow into the estuary is generally much less.

The increase in dissolved-solids concentration between Trenton and 

Marcus Hook is due in small part to added industrial and municipal

7710-402 Oi 65 4
O22 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES 

02000

01000

1 800 

oc

i 600

400

200

8> 100

1 I

I I I I

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

FIGURE 15. Mean monthly conductivity of water in Delaware River 

between Bristol and Marcus Hook, 1949-63. See figure 1 for location 

of stations 1, 3, 5, 7, and 8.

wastes, but mostly to sea water brought upstream by tidal action. 

That a relation exists may be shown by comparing the composition 

of the dissolved solids in the water at Marcus Hook with that of the 

dissolved solids at Trenton and in ocean water. In table 5 the composition of the dissolved solids in river water at Trenton and in 

estuary water at Marcus Hook are compared to ocean water in terms 

of the ratios, by weight, of chloride to sulfate, chloride to magneTABLE 5. Comparison of ratios of dissolved solids in Delaware River at Trenton 

and Marcus Hook with ratios of dissolved solids in ocean water

a

b

c

d

Date

Oct. 8, 1957._._

Aug. 2, 1955 .

Apr. 3, 1958 _ .

May 4, 1953 __

Discharge

at Trenton

(cfe)

1,740

1,970

33, 000

27, 900

Dissolved-solids

concentration

(ppm)

Trenton

121

132

56

72

Marcus

Hook

3,840

2,180

142

91

Ratio (by weight)

Solids

C1:SO4

Cl:Mg

MgrCa

C1:SO4

ClrMg

MgrCa

C1:S04

Cl:Mg

MgrCa

C1:SO4

ClrMg

Mg:Ca

Trenton

0.4

1.5

.3

.4

1.9

.4

.1

1.1

.2

.3

1.6

.3

Marcus

Hook

4.7

16.3

1.7

4.0

15.3 

1.6

.1

1.3

.2

.2

1.8

.3

Ocean

water

7.2

14.8

3.1

7.2

14.8 

3.1

7.2

14.8

3.1

7.2

14.8

3.1
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK O23

70

60

50

40

30

20

CJ

5

>- 10 

OQ 9

til a ?n

< 7

2 6 

o

" 5 

a! 

4

I I I I I I I II II I

8

i i i

§ 8 « in

DISSOLVED SOLIDS, IN PARTS PER MILLION

FIGTTKB 16. Relation between concentration and composition of dissolved solids 

in Delaware River water between Bristol and Marcus Hook, 1950-62.

slum, and magnesium to calcium. At low flow the ratios at Marcus 

Hook (table 5), items a and b are much more like those for ocean 

water than for fresh water (Trenton), and this similarity indicates 

that the increase in salinity between Trenton and Marcus Hook is 

largely due to the admixture of ocean water with the fresh river 

water.

At high fresh-water discharge rates, there is less mixing with sea 

water in this lower reach of the river, because of the flushing effect 

of the fresh water. This fact is evident from items c and d in table 5. 

Thus, at high flows the dissolved solids at Marcus Hook have nearly 

the same composition as those in the fresh water at Trenton. At 

low flows the composition of the dissolved solids in Delaware River 

water approaches that of the dissolved solids in ocean water.
O24 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

28 percent

26 percent

24 percent

Trenton 

56-114 ppm dissolved solids

HCOa 

percent

8 percent

13 percent\(Na 

11 percent 11 percent

100 ppm dissolved solids

41 percent 

2000 ppm dissolved solids

FIGURE 17. Typical composition of dissolved solids in the Delaware River and 

estuary, by percentage of chemical equivalents.

CHLORIDE

The annual mean chloride concentration at Marcus Hook varied 

from 19 to 663 ppm, and at Burlington-Bristol Bridge from 5.1 to 

9.0 ppm (fig. 18). The highest chloride concentrations in the river 

below Philadelphia were experienced in 1953, 1954, 1957, and 1963. 

Salinity incursions may also be described in terms of the maximum 

salinity each year (fig. 19) or, with more significance for the user 

of water, in terms of the number of days each year during which 

a given salinity is reached or exceeded at some point in the river. 

Table 6 shows the number of days each year when the average 

chloride concentration exceeded 400 ppm at Marcus Hook, and the 

daily maximum chloride concentration exceeded 50 ppm at Bridesburg, Pa., and 400 ppm at Chester, Pa. Again the years of greatest 

salt-water incursion were 1949, 1953, 1954, 1957, and 1963. In each 

of these 5 years (except in 1953), the annual flow was below the 

average; however, the annual flow was below average in 1950, 1955, 

1959, 1961, and 1962 also, but the chloride concentration was not 

unusually high in these years. The monthly discharge of fresh water 

at Trenton was below average in each of the months from June to 

October in 1949, 1953, 1954, 1957, and 1963, and also in 1962.
350

300

1950 61 62 1963

FIGURE 18. Annual mean chloride concentrations in Delaware River between Bristol and Marcus Hook, 1950-63. See figure 1

for location of stations 1, 4, 7, and 8.

oto
O26 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNTIED STATES

2000

1950 51 52 53 54 55 56 57 58 59 1960 61 62 1963

FIGURE 19. Annual maximum chloride concentrations in Delaware 

River between Bristol and Marcus Hook, 1950-63. See figure 1 for 

location of stations 1, 4, 7, and 8.

The frequency with which various chloride concentrations in the 

estuary occurred during 1950-63 is shown in figures 20 and 21. For 

example, a chloride concentration of 10 ppm or greater occurred 

15 percent of the time at Burlington-Bristol Bridge, 45 percent of 

the time at Benjamin Franklin Bridge, 56 percent of the time at 

Eddystone, and 74 percent of the time at Marcus Hook. A chloride 

concentration of 100 ppm or greater was observed at Benjamin 

Franklin Bridge only 2 percent of the time, at Eddystone 9 percent 

of the time, and at Marcus Hook 24 percent of the time.

The mean monthly chloride concentrations during 1950-62 are 

plotted in figure 22. As with dissolved solids and conductivity 

(fig. 15), the chloride concentrations are least in December to May 

and greatest in August to November.
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK O27

TABLE 6. Number of days each year in which selected chloride concentrations were 

exceeded for a salt-water invasion, Delaware River at Bridesburg, Chester, and 

Marcus Hook, Pa., and average June to October discharge at Trenton, N.J., for 

each year.

[Chloride data furnished by Rohm and Haas Co. for Brldesburg; Scott Paper Co. for Chester; Sun Oil Co.

for Marcus Hook]

Year

1949 . . _ .. .. __ .

1950. ____ ____.___......

1951__ ___ -_.-_-___-._._

1952_____. ____.._.___.._.

1953. ___----------___..__

1954_. __.__.._..______.__

1955__-___---_-_--_______

1956. ____________ _ .._._

1957______-______________

1958-______..____. __._._.

1959 __ --_-___-__-_-_____

1960_-.---_.__. ___._._.__

1961___-_-._. .._----_..__

1962___. _________________

1963 __ -_---_____----.___

Days daily maximum 

chloride concentration 

exceeded 

50ppm

Bridesburg, 

Philadelphia, Pa.»

0 

0 

0 

9 

32 

0 

0 

86 

0 

0 

0 

0 

0 

16

400 ppm

Chester, Pa.1

Ill 

9 

6 

11

119 

29 

0 

132 

0 

0 

0 

21 

13 

122

Days daily average chloride 

concentration 

exceeded 

400 ppm

Marcus Hook, Pa.2

120 

17 

22 

17 

98 

128 

36 

0 

144 

0 

0 

0 

35 

31 

141

Average daily 

discharge at 

Trenton, N.J., 

June to October 

(cfs)

3,522 

6,382 

6,621 

9, 103 

3,709 

2,996 

14, 781 

6,680 

2,771 

5,369 

4,954 

10, 277 

4,990 

3,210 

3,009

1 Bridesburg and Chester data are based on samples collected at high tides.

2 Marcus Hook data represent the analyses of daily composites of hourly samples (compiled by Frederick 

Schaefer for report of the River Master for the year ending Nov. 30,1963).

DISSOLVED OXYGEN

The annual mean dissolved-oxygen concentrations at five locations 

in the Delaware estuary are plotted in figure 23. Dissolved oxygen 

decreases from Bristol to Marcus Hook, the sharpest decrease occurring between Torresdale and Lehigh Avenue. Minimum dissolvedoxygen concentrations are plotted in figure 24. The very low minima 

in 1950-53 have not been repeated in later years. In general, the 

lowest concentrations are found near Wharton Street, and a slight 

recovery is made between there and Marcus Hook. Figure 25 is a 

frequency plot of dissolved oxygen in percent saturation. Five percent of the samples at Marcus Hook, 15 percent of those at Benjamin 

Franklin Bridge, 62 percent of those at Torresdale, and 76 percent 

of those at Bristol were at least 75 percent saturated. All these 

samples were taken in the daytime, and the average daily dissolvedoxygen concentrations very possibly were lower than those represented by the figures tabulated and plotted. For example, upstream 

at Trenton the dissolved-oxygen concentration varies diurnally as a
O28 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

2000

1000

800

600

400

S 200

</) 

a:£

? 100

I 80 

o

I 60 

o

40

20

10

\

\

\

Example: Chloride concentrations were 200 

ppm or higher 12 percent of the time from 

1930 to 1961

Y

\

5 10 20 30 40 50 60 70 80

PERCENT OF SAMPLES IN WHICH CHLORIDE CONCENTRATIONS

EQUALED OR EXCEEDED THAT SHOWN

90

FIGURE 20. Frequency of various chloride concentrations in Delaware 

River at Chester, Pa., 1930-61.

result of photosynthesis. The minimum daily dissolved oxygen, 

about 6-8 ppm, occurs between 5:00 and 6:00 a.m. in the morning. 

During daylight hours the dissolved-oxygen concentration increases 

to as high as 14 ppm.

In recent years, dissolved oxygen in the estuary has been measured 

by instruments that record continuously so that daily average concentrations could be obtained. Table 7 shows the frequency with 

which low values of dissolved oxygen have been experienced at three 

dissolved-oxygen recorders on the estuary.
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK O29

100

90

80

70

60

50

40

30

020

a:

LJ

£L

§10 

Q. 9

? 8

LU 7 

9

I 6

5 5

10 20 30 40 50 60 70 80 90 95 98 

PERCENT OF SAMPLES IN WHICH CHLORIDE CONCENTRATIONS 

EQUALED OR EXCEEDED THAT SHOWN

99

FIGURE 21. Frequency of various chloride concentrations in Delaware 

River, 1950-62. See figure 1 for location of stations 1, 4, 6, and 8.

Figure 26 shows the monthly variation in dissolved-oxygen concentration during 1950-63. The concentration is lowest in those 

months when the water temperature is highest, because less oxygen 

dissolves in warm water than in cold water and because the biochemical reactions that consume oxygen occur at accelerated rates at 

higher temperatures.
030 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

TABLE 7. Number of days dissolved-oxygen concentration was less than 1 and 

8 ppm at three dissolved-oxygen recorders in the Delaware River, March 1961- 

December 1963

1961 

March . _

April... .......... .........

Mftv

July.............. ..... .

1961

April... ...................

July..........................

September ....................

December ....................

1963

April. _ . ___ . ___ ......

May ..........................

July....... ...................

August .......................

October. ___________

December ....................

Number of days

Concentration <1 ppm

Torresdale

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

14 

10 

9 

0 

0 

0 

0

0 

0 

0 

0 

0 

2

0 

0 

0 

0 

0

Benjamin 

Franklin 

Bridge

0 

0 

0 

26 

31 

31 

30 

31 

23 

0

0 

0 

0 

0 

26 

30 

31 

31 

30 

29 

2 

0

0 

0 

0 

0 

21 

30 

31 

31 

30 

31 

26 

0

Chester

0 

0 

0 

0 

29 

27 

31 

31 

30 

26 

7 

0

0 

0 

0 

0 

26 

29 

31 

31 

30 

31 

23 

3

Concentration<3 ppm

Torresdale

0 

0 

0 

5 

22 

17 

7 

0 

0 

0

0 

0 

0 

0 

2 

30 

26 

31 

24 

0 

0 

0

0 

0 

0 

0 

0 

21 

25 

14 

9 

3 

0 

0

Benjamin 

Franklin 

Bridge

0 

0 

9 

30 

31 

31 

30 

31 

27 

0

0 

0 

0

1

31 

30 

31 

31 

30 

31 

5 

0

0 

0 

0 

6 

31 

30 

31 

31 

30 

31 

30 

8

Chester

0 

0 

0 

2 

31 

30 

31 

31 

30 

31 

13 

0

0 

0 

0 

7 

30 

30 

31 

31 

30 

31 

30 

14

Additional information on dissolved-oxygen concentrations is 

shown in figure 27. The average dissolved-oxygen concentration and 

the range of concentrations is plotted for stations (a) upstream from 

central Philadelphia, (b) near central Philadelphia, and (c) downstream from central Philadelphia, for four periods of the year. The 

data show that the concentration of dissolved oxygen is lowest in 

June to September and highest in December to March, that it decreases as the water flows downstream past Philadelphia, and that 

it decreases still further in December to May as the water flows on 

to Marcus Hook.

SUSPENDED SEDIMENT

The yearly changes in suspended-sediment concentration are shown 

in figure 28. The determinations shown in this figure are the ratio
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK 031

500

400

300

200

§ 100

3 90

I 80

a 70

£ 60

v> 50

5 40

Q_

2 30

20

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

FIGURE 22. Mean monthly chloride concentrations in Delaware 

River, 1950-62. See figure 1 for location of stations 1, 3, 5, 7, 

and 8.

of dry weight of sediment to the total weight of the water-sediment 

sample as measured on composite samples at each station. Although 

the sediments are composite, the determinations are adequate to show 

gross changes in suspended-sediment concentration; however, they 

should not be used to calculate the load of sediment transported, for 

no consideration has been given to the differences in rates of flow 

in different parts of the cross sections.

Until 1957 the sediment concentration increased from Bristol 

downstream to Marcus Hook. The change in this situation after 

1959 is probably related to channel-dredging activities in the river 

upstream from the Benjamin Franklin Bridge. At times the increase in sediment was evident in the muddy appearance of the river
O32 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

1950 51 52 53 54 55 56 57 58 59 1960 61 62 1963

100

1950 51 52 53 54 56 57 58 59 1960 61 62 1963

FIGURE 23. Annual mean dissolved-oxygen concentrations in Delaware River, 

1950-63. See figure 1 for location of stations 1, 2, 3, 4, and 8.

	80

UJ U-

£! ° Z 60

X HO

Q O !$ 40 uj a: ^

> UJ ^

8 z w 20

I I I I I I I I I ( I I 

1950 51 52 53 54 55 56 57 58 59 1960 61 62 1963

FIGURE 24. Annual minimum dissolved-oxygen concentrations in Delaware River, 1950-63. See figure 1 for location of stations 1, 5, and 8.
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK Q33

at Philadelphia. Monthly sediment concentrations shown in figure 

29 are based on data from August 1949 to December 1959. Higher 

concentrations generally occur in the months of higher streamflow, 

when the water is more turbulent than in the low-flow months.

100

90

80

70

60

50

40

Q 30

20

10

\

\

Vvft

\

\

X

\

\

5 10 20 30 40 50 60 70 80 90 95

PERCENT OF SAMPLES IN WHICH DEGREE OF SATURATION

EQUALED OR EXCEEDED THAT SHOWN

98

FIGURE 25. Frequency of given dissolved-oxygen concentrations in 

Delaware River, 1950-63, in percent saturation. See figure 1 for 

location of stations 1, 2, 4, and 8.
<

o

 +0 UU

II
It

13

12

z 11

O

j

i

DC

LLJ Q 

0. y

IE 8

Q.

S 7

z"

CD 6 >-

g

Q 5

UJ

5 3

2

1 

n

DEC JAN FEB MAR

/Average

- *i

"</>

- o

1

 ui

«*

APR MAY JUNE JULY AUG SEPT

CM

^H ^

 ».

s

1

m" CO

1 »-

(f) C

o

_ (O^

-

in

co"

V)

*^

^

c

in

co" 0

OCT NOV

-

_

in

0 c<

co"

V)

1

 " 

J

I

~ (0

tg

 ^

A

V)

rC *^

S o5

«« _

j

i

i i

V)

/) c

2

0

1

rC

<O

1

-

__ -

-

FIGURE 27. Average dissolved-oxygen concentration and range of central 80 percent of concentrations 

at selected groups of stations in each of four periods of the year, 1950-63. See figure 1 for location 

of stations.

O 

oo 

en
O36 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

100

I I I I I I I I I I

1950 51 52 53 54 55 56 57 59 1960 61 62 1963

FIGURE 28. Annual mean suspended-sediment concentrations in Delaware 

River, 1950-63. See figure 1 for location of stations 1, 4, and 8.

80

o

n 60

20

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

FIGURE 29. Mean monthly suspended-sediment concentrations in 

Delaware River at Bristol and Marcus Hook, 1950-62. See 

figure 1 for location of stations 1 and 8.

TABULAR SUMMARIES OP WATER-QUALITY 

CHARACTERISTICS

The monthly analyses of the 14-year period are summarized in 

tables 9,10, and 11. Each table contains eight divisions, one for each 

of the eight sampling locations; these divisions are identified by title 

and by the number used to identify the sampling location in figure 1 

and in table 1. For example, table 9 (3) gives a summary for station 3, Lehigh Avenue, Philadelphia.

Table 8 gives physical descriptions of each of the eight sampling 

stations. The locations are given in distances upstream or downstream from Allegheny Avenue, Philadelphia, Pa., measured along 

the centerline of the navigation channel in units of 1,000 feet. Locations upstream from Allegheny Avenue are labeled ( ), and those 

downstream (+). Thus, the Bristol-Burlington Bridge station is 

79,200 feet upstream from Allegheny Avenue. Details of each sampling location are given in the maps referred to in table 8. These 

maps can be obtained from the Corps of Engineers, Philadelphia
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK 037

District, and from the U.S. Coast and Geodetic Survey. Included 

in the physical description is the "Accumulated volume" for each 

station, that is, the quantity of water to fill the river at midtide 

level, from head of tide to the sampling station.

Table 9 is a frequency distribution for selected percentile groups 

of pH, specific conductance, chloride, water temperature, and dissolved oxygen for each of the eight sampling stations. For example, 

table 9 (1) shows that at Bristol-Burlington Bridge cross section 

the pH ranged from 6.2 to 7.8 and that the median pH was 6.9 (that 

is, that the pH was less than 6.9 as frequently as it was greater).

Table 10 gives the annual maximum, mean, and minimum measurements of specific conductance, chloride, suspended sediment, water 

temperature, and dissolved oxygen; and for pH, the annual maximum, median, and minimum. Monthly maximum, mean (median 

for pH), and minimum measurements for the same characteristics 

are listed in table 11.

TABLE 8. Physical description of sampling locations

1. Bristol (Pa.)-Barltngton <NJ.) Bridie station

LOCATION: In Devlin navigation range 1,300 ft upstream from bridge on a line 

from Pennsylvania bank (right) through channel station 79.2 to Lehigh range 

light on New Jersey bank (left), approximately 15 miles downstream from head 

of tide at Trenton, N.J. 

SAMPLING POINTS:

Right side: 200 ft from Pennsylvania bank on line with No. 2 suspender

which is to the right of right tower of bridge. 

Right center: 475 ft from Pennsylvania bank on line with right tower and

buoy C-43.

Center: 825 ft from Pennsylvania bank on line 40 ft left of centerline of bridge. 

Left center: 1,050 ft from Pennsylvania bank on line with left tower of bridge. 

Left side: 1,275 ft from Pennsylvania bank (25 ft from New Jersey and Lehigh

range light).

DRAINAGE AREA: 7,160 sq mi.

ACCUMULATED VOLUME : 1,635 million cu ft, below the head of tide at Trenton, N.J. 

REFERENCE MAPS:

Corps of Engineers, Delaware River, Burlington to Bristol, file No. 25006. 

U.S. Coast and Geodetic Survey, Delaware River, Philadelphia, Pa., to Trenton, 

N.J., No. 296.

2. Torresdale, Philadelphia, .station

LOCATION: On a line from brick building on bulkhead line at filter plant through

channel station 37.0 to New Jersey bank. (Brick building is the site of an

inactive water intake for filter plant. Present intake to sedimentation basin is

2,400 ft upstream from sampling location). 

SAMPLING POINTS:

Right side: 30 ft from intake building.

Right center: 425 ft from intake building.

Center: 900 ft from intake building.

Left center: 1,400 ft from intake building.

Left side: 1,800 ft from intake building (400 ft from New Jersey bank).
O38 CONTRIBUTIONS TO THE HYDROLOGY OF .THE UNITED STATES

DRAINAGE AREA: 7,781 sq mi.

ACCUMULATED VOLUME : 3,088 million cu ft, below the head of tide at Trenton, N. J.

REFERENCE MAPS:

Corps of Engineers, Delaware River, Ten Mile Point to Rancocas River,

file No. 25003.

U.S. Coast and Geodetic Survey, Delaware River, Philadelphia, Pa. to Trenton, 

N.J., No. 296.

3. Lehigh Avenue, Philadelphia, station

LOCATION: On a line midway between piers 14 and 18 Port Richmond Terminal

through channel station +5.0 to pierhead line on Petty Island. (Aug. 1949-

Dec. 1952, 800 ft upstream from here.) 

SAMPLING POINTS:

Right side: 50 ft from Pennsylvania pierhead line.

Right center: 500 ft from Pennsylvania pierhead line.

Center: 950 ft from Pennsylvania pierhead line.

Left center: 1,450 ft from Pennsylvania pierhead line.

Left side: 1,850 ft from Pennsylvania pierhead line (50 ft from pierhead line

on Petty Island). 

DRAINAGE AREA: 7,935 sq mi. 

ACCUMULATED VOLUME: 5,363 million cu ft, below the head of tide at Trenton,

N.J. 

REFERENCE MAPS:

Corps of Engineers, Delaware River, Cooper Point to Fisher Point, file No. 

17112.

U.S. Coast and Geodetic Survey, Delaware River, Philadelphia and Cam den 

waterfronts, No. 280.

4. Benjamin Franklin Bridge station

[At one time this -was known as the Philadelpbia-Camden Bridge station]

LOCATION: On a line 200 ft upstream of bridge from north side of pier 12 North 

through channel station +14.3 to pierhead line on New Jersey side of river. 

(Aug. 1949-Dec. 1952, 400 ft upstream from here.) 

SAMPLING POINTS:

Right side: At Philadelphia pierhead line.

Right center: 425 ft from Philadelphia pierhead line (midway between right

bridge abutment and centerline of bridge).

Center: 850 ft from Philadelphia pierhead line (centerline of bridge). 

Left center: 1,250 ft from Philadelphia pierhead line (midway between left

bridge abutment and centerline of bridge). 

Left side: 1,700 ft from Philadelphia pierhead line (on line with right side of

left bridge abutment on pierhead line). 

DRAINAGE AREA: 7,993 sq mi. 

ACCUMULATED VOLUME: 5,869 million cu ft, below the head of tide at Trenton,

N.J.

REFERENCE MAPS: 

Corps of Engineers, Delaware River, Gloucester, N.J., to Cooper Point, file

No. 17111.

U.S. Coast and Geodetic Survey, Delaware River, Philadelphia and Camden 

waterfronts, No. 280.

5. Wharton Street, Philadelphia, station

LOCATION: On a line between piers 53 and 55 South, Philadelphia, through channel 

station +22.6 to coal pier on New Jersey side of river. (Aug. 1949-Dec. 1952, 

250 ft downstream from here.)
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK O39

SAMPLING POINTS:

Right side: 50 ft from Philadelphia pierhead line.

Right center: 500 ft from Philadelphia pierhead line.

Center: 1,000 ft from Philadelphia pierhead line.

Left center: 1,500 ft from Philadelphia pierhead line.

Left side 1,950 ft from Philadelphia pierhead line (50 ft from coal pier on New

Jersey side).

DRAINAGE AREA: 7,998 sq mi. 

ACCUMULATED VOLUME: 6,380 million cu ft, below the head of tide at Trenton,

N.J.

REFERENCE MAPS: 

Corps of Engineers, Delaware River, Gloucester, N.J., to Cooper Point, file

No. 17111.

U.S. Coast and Geodetic Survey, Delaware River, Philadelphia and Camden 

waterfronts, No. 280.

6. League bland, Philadelphia, station

LOCATION: On a line from north side of naval yard pier 4 through channel station

+ 51.3 to covered wharf at Red Bank, N.J. (below ferry slip). (Aug. 1949-

Dec. 1952, on line from pier 2 through channel station +50.8.) 

SAMPLING POINTS:

Right side: 25 ft from naval yard pierhead line.

Right center: 600 ft from naval yard pierhead line.

Center: 1,200 ft from naval yard pierhead line.

Left center: 1,800 ft from naval yard pierhead line.

Left side: 2,200 ft from naval yard pierhead line (50 ft from wharf, New Jersey

side).

DRAINAGE AREA: 8,072 sq mi. 

ACCUMULATED VOLUME: 8,507 million cu ft, below the head of tide at Trenton,

N.J. 

REFERENCE MAPS:

Corps of Engineers, Delaware River, Schuylkill River to Gloucester, N.J., file 

No. 17110.

U.S. Coast and Geodetic Survey, Delaware River, Philadelphia and Camden 

waterfronts, No. 280.

7. Eddystone, Pa., station

LOCATION: In Tinicum navigation range on a line between piers 11 and 12 just

above Chester Front light through channel station +97.2 to the middle of

Monds Island on New Jersey shore. (Aug. 1949-Dec. 1952, 400 ft upstream

from here.) 

SAMPLING POINTS:

Right side: 20 ft from pierhead line, on Pennsylvania side.

Right center: 800 ft from pierhead line, on Pennsylvania side.

Center: 1,600 ft from pierhead line, on Pennsylvania side.

Left center: 2,500 ft from pierhead line, on Pennsylvania side.

Left side: 3,300 ft from pierhead line, on Pennsylvania side. 

DRAINAGE AREA: 10,190 sq mi. 

ACCUMULATED VOLUME: 13,274 million cu ft, below the head of tide at Trenton,

N.J. 

REFERENCE MAPS:

Corps of Engineers, Delaware River, Marcus -Hook to Eddystone, Pa., file 

No. 25603.

U.S. Coast and Geodetic Survey, Delaware River, Wilmington to Philadelphia, No. 295
O40 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

8. Marcus Hook, Pa., station

LOCATION: In Marcus Hook navigation range on a line (below State line) from

the water end of the Maritime Exchange reporting station pier through channel

station +128.7 to vertical lift bridge over Oldmans Creek. 

SAMPLING POINTS:

Right side: 25 ft from pierhead line, on Pennsylvania side.

Right center: 825 ft from pierhead line, on Pennsylvania side.

Center: 1,700 ft from pierhead line, on Pennsylvania side.

Left center: 2,200 ft from pierhead line, on Pennsylvania side.

Left side: 3,100 ft from pierhead line, on Pennsylvania side. 

DRAINAGE ABBA: 10,370 sq mi. 

ACCUMULATED VOLUME: 17,068 million cu ft. below the head of tide at Trenton,

N.J. 

REFERENCE MAPS:

Corps of Engineers, Delaware River, Edgemoore, Del., to Marcus Hook, Pa., 

file No. 25602.

U.S. Coast and Geodetic Survey, Delaware River, Wilmington to Philadelphia. 

No. 295.

LOCAL, VARIATIONS IN WATER-QUALITY PATTERNS

Because the river water was sampled each month at eight locations, it is possible to show the water-quality changes from month 

to month and from year to year at each of these sampling locations. 

Furthermore, the median or average values of the water-quality 

parameters and the frequency of occurrence of various values of 

these parameters are also shown. Because cross-section samples were 

taken at each of the eight sampling locations, variations in the waterquality parameters may also be discussed for each of the cross 

sections.

At Burlington-Bristol Bridge, Benjamin Franklin Bridge, and 

Marcus Hook (stations 1, 4, and 8), top and bottom water samples 

were collected at five points in the river cross section. Top samples 

were collected 3 feet below the water surface; bottom samples, approximately 3 feet above the riverbed. At the other stations (2, 3, 

5, 6, and 7, fig. 1), top samples were collected at five points in the 

cross section, but bottom samples only at the three center points.

In general, the cross sections are uniform in water quality, but 

river curvature, channel depth, islands, bars, and physical structures 

do affect the direction of ebb and flood currents. These features may 

influence the mixing of tributary streams, wastes, or sediment with 

the water in the main stream, thus causing variations in water 

quality across the cross section of the river.

At Bristol and at the Benjamin Franklin Bridge, the water on the 

Pennsylvania side generally has a higher specific conductance (about 

5 percent higher) than the water in the rest of the cross section. At 

Marcus Hook the water on the Pennsylvania side of the river has 

a higher conductance when the specific conductance is less than 600 

(Text continues on page O52.)
TABLE 9. Range and frequency distribution of selected percentile groups of water-quality parameters, Delaware River, 1949-68 l 

[Percent of average cross-section water-quality measurements in which parameter equaled or exceeded value tabulated]

Maximum 

value

Value, In parts per Billion, equaled or exceeded by indicated percent of samples

5 10 25 50 75 90 95

Minimum 2 

value ^4

5

1. Delaware River at Brtetol-Bnrlincton Bridge, 1949-68 >

h-(

Hydrogen ion concentration _ __________pH__ 

Specific conductance. ..micromhos at 25° C___ 

Chloride _ __ ______________________ _ppm_ _ Water temperature. __._ ______________F__

Dissolved oxygen _ ____ ___________-ppm__

Do ____ _ _-_-_-__ _ .percent saturation _

7.8 

266 

17 

86 

13.3 

106

7.3 

225 

13 

83 

12.0 

98

7.2 

215 

11 

81 

11.8 

96

7.1 

190 

8.2 

74 

11.0 

90

6.9 

145 

6.0 

56

8.8 

84

6.8 

115 

4.5 

41 

7.0 

76

6.7 

105 

3.6 

37 

5.5 

67

6.5 

95 

3.1 

36 

4.6 

60

6.2 a

60 3 si- 2 ;

2.3 ^

30 1

2. Delaware River at Torresdale intake, Philadelphia, Pa., 1949-63

Nrt

Hydrogen ion concentration ___ _____pH____ 

Specific conductance... -micromhos at 25° C__ 

Chloride- ______ _ ________________ppm__

Water temperature.-....-.---.....-.-. F__

Dissolved oxygen _ __ _______________ ppm. _

8.7 

278 

26 

86 

13.4 

104

7.2 

232 

15 

83 

12.2 

97

7.2 

216 

13 

80 

11.6 

93

7.0 

180 

8.5 

75 

10.5 

87

6.9 

150 

6.2 

56

8.4 

79

6.7 

120 

4.9 

41 

6.2 

69

6.6 

105 

3.8 

37 

4.7 

55

6.5 

95 

3.0 

36 

4.0 

45

» 

6.1 % 

57 g 

2.0 g 

33 

2.3 g 

29

fii 

3. Delaware River at Lehigh Avenue, Philadelphia, Pa., 1949-63 3

Hydrogen ion concentration __ _ ________ pH_

Specific conductance. --.micromhos at 25° C__ 

CJhloride.- ________________ __________ppm__ 

Water temperature. ____ ______________ F__

Dissolved oxygen.... __________ _ ____ppm._

Do____ _ _________ .percent saturation. _

7.6 

571 

97 

85 

12.7 

101

7.1 

375 

35 

83 

11.4 

89

7.0 

280 

22 

81 

10.8 

85

6.9 

215 

12 

75 

9.5 

78

6.7 

165 

8.0 

56 

6.5 

60

6.6 

130 

5.3 

41 

2.5 

30

6.5 

110 

4.0 

37 

1.6 

20

6.4 

105 

3.7 

36 

1.0 

11

GO

6.0 M 

57 g 

2.5 o 

33 W 

.2 8 s?

See footnote at end of table.
TABLE 9. Range and frequency distribution of selected percentile groups of water-quality parameters, Delaware River, 1949-68 J Con. 

[Percent of average cross-section water-quality measurements in which parameter equaled or exceeded value tabulated]

Maximum 

value

Value, in parts per million, equaled or exceeded by Indicated percent of samples

5 10 25 60 76 90 96

Minimum 

value

4. Delaware River at Benjamin Franklin Bridge, 1949-63

Hydrogen ion concentration. __ _ ______ _pH _ _

Specific conductance. __ .micromhos at 25° C__ 

Chloride __ _________________________ppm__

Water temperature. .__ ______________ F_

Dissolved oxygen.. ________ __________ppm__

Do. _ _______________percent saturation..

7.7

876 

172

84

12.5

100

7.1

390

48

83

10.7

87

7.0

310 

27

SO

10.0

80

6.8

230 

14

75

9.2

70

6.7

170

8.8

56

5.7

55

6.5

130 

6.3

42

2.0

22

6.4

120 

5.0

37

1.0

15

6.3

110 

4.5

36

0.8

9.0

6 0

61 

3.3

33

0.0

0

5. Delaware River at Wharton Street, Philadelphia, Pa., 1949-63

Hydrogen ion concentration __ _ _______pH__

Specific conductance. __ .micromhos at 25 s C__ 

Chloride __ ___ _ _____________ ___ _ppm__

Water temperature. _____________ _____ F__

Dissolved oxygen__ _ _________________ _ppm_ _ 

Do. _______________ .percent saturation. _

7.5

753 

137

85

11.6 

91

7.0

465 

62

83

10.5 

86

6.9

335

28

81

9.9 

80

6.8

250 

15

75

8.5 

66

6.6

185 

9.6

59

4.1 

42

6.5

140 

6.6

43

1.8 

20

6.4

120 

5.1

38

1.0 

11

6.3

110 

4.4

36

.5 

5

5.9

68 

2.0

34

6. Delaware River at League bland, Philadelphia, Pa., 1949-63

S

Ed

Hydrogen ion concentration ___________ _pH _

Specific conductance. ___micromhos at 25° C_. 

Chloride __ _______________________ _ _ppm_ _ Water temperature. ____ ______________ F__

Dissolved oxygen.. _ _________________ _ppm_ _

Do ________________ .percent saturation. _

7.6

1,180 

275

86

12.1

94

7.0

680 

144

83

10.3

82

6.9

470 

50

81

9.5

71

6.7

270 

16

75

7.9

63

6.6

210 

11

59

3.4

38

6.4

160

7.7

43

1.9

23

6.3

135

5.8

38

1.2

15

6.2

120 

4.8

37

.5

10

9 

5.9 |

7?.7 I

34 o,

ft fi

0 fe

§
7. Delaware River at Eddystone, Pa., 1949-63

Hydrogen ion concentration __ ________ _pH _ _

Specific conductance ._ __micromhos at 25 C__ 

Chloride __ _ _______________________ -ppm_ - 

Water temperature. _________-____--___ 6 F__

Dissolved oxygen__ _ ________________ _ppm_ _

Do _______ ________ .percent saturation. _

7.4

3,620 

972 

86

11.4

91

7.0

1,600 

440 

83

9.6

77

6.9

980 

230 

81

8.5

68

6.7

310 

25

75

7.2

58

6.6

220 

13

58

4.0

40

6.4

180 

9.0 

43

2.3

26

6.3

150 

6.8 

39

1.3

17

6.2

140 

5.8 

37

1.0

12

6.0

78 

4.0 

34

.5

6

8. Delaware River at Marcus Hook, Pa., 1949-63

Hydrogen ion concentration __ ________ _pH _ _ 

Specific conductance- __ .micro mhos at 25° C__ 

Chloride __ _ _______________________ _ppm_ _ Water temperature. ___________________ F__

Dissolved oxygen.. __________________ _ppm_ _ 

Do ... ____________ .percent saturation. _

7.7 

6,500 

1,940

86

10.7

87

6.9 

3,100 

1,140

83

9.5 

76

6.8 

2,200 

620

81

8.5 

67

6.6 

550 

90

75

7.0 

57

6.5 

250 

15

57

4.5 

43

6.3 

190 

9.8

44

2.5 

30

5.9 

160

7.4

39

1.7 

20

5.7 

145 

6.4

38

1.4 

15

£ 

5.0 » 

89 <_ 

4.7 £

34 3

1.0 g 

11 -

W

1 Averages of 6-polnt cross-section samples collected monthly August 1949-July 1963.

I

O

W

2

CO
TABLE 10. Annual maximum, mean, and minimum of water-quality parameters, Delaware River, 1950-83 l

Year

Hydrogen ion 

(pH)

Max Median Mln

Specific conductance 

(mlcromhosat26°0)

Max Mean Min

Chloride (ppm)

Max Mean Min

Suspended sediment 

(ppm)

Max Mean Min

Water temperature 

CFf

Max Mean Min

Dissolved oxygen

Farts per million

Max Mean Min

Percent saturation

Max Mean Min

1. Delaware River at Bristol-Burlington Bridge, 1950-63

1950. 

1951. 

1952 

1953 

1954..... _ ...

1955X _ 

1956 

1957 - 

1958. _

1959...........

I960..... ......

1961. ......

1962...........

1963...........

7.1

7.2

7.2

7.0

7.2

7.1

7.8

7.2

7.3

7.4

7.3

7.1

7.2

7.3

6.8

6.9

6.7

6.8

6.9

6.7

6.9

7.0

7.0

6.9

7.0

6.8

7.1

7.1

6.5

6.5

6.4

6.6

6.7

6.2

6,7

6.7

6.4

6.6

6.8

6.7

6.9

6.8

213

216

235

256

252

245

197

236

193

200

167

222

223

266

135

138

147

163

165

145

155

178

141

152

139

143

164

186

76

60

Bfi

on

97

84

95

119

104

91

81

95

80

80

11

11

10

16

17

16

7.9

13

8.1

10

8 4

12

11

14

5.9

5.3

5.1

8.0

9.0

6.7

5.5

8 4

5.1

6.6

5.3

7.0

7.9

8.6

3.3

2.7

2.2

3.6

4.0

2.7

2.9

4.4

3.2

4.0

2.6

3.1

4.0

2.3

40

142

73

38

32

53

26

61

54

39

332

208

238

167

18

36

94

15

17

23

16

28

27

24

178

62

75

81

8

7

9

7

7

9

10

13

11

14

18

21

21

30

79

76ai

fifi

80

85

an

85

82

QA

76

84

81

83

57

57

57

K8

56fia

56

57

55

en

60

58

57

59

34

34

38

36

36

34

35

36

33

35

3ft

34

34

35

13.3

12.9

12.2

11.7

11.8

11.5

11.7

11.5

11.7

11 8

11.9

11 Q

12.6

12.9

9.1

9.6

9 1

8 4

A 7

9.2

9.0

8 1

8.8

9.0

B n

7.9

8 4

7.4

4.0

6.4

4.5

3.5

2.8

4.5

6.3

5.0

5.9

5.5

5.0

4.4

3.2

2.3

98

104

97

94

89

93

88

84

97

92

93

90

95

95

80

81

81

67

78

83

77

67

76

76

70

72

79

68

ft,

ft

51

3)

6

5!

&

41

6

5!

ft

K

31

3

2. Delaware River at Torresdale intake, Philadelphia, Pa., 1950-63

1950. ......

1951 

1952........ _

1953 

1954 

1955 

1956...........

1957.... .......

1958 ......

1959. .......

I960...........

1961. ......

1962...........

1963...........

7.2

7.1

7.1

7.0

7.8

7.2

7.1

7.2

7.4

7.2

7.4

7.2

7.2

7.2

6.8

6.8

6.6

6.8

6.9

6.8

6.8

6.8

7.0

6.9

6.9

6.9

7.0

7.0

6,5

6.6

6.3

6.5

6.5

6.4

6.6

6.5

6.2

6.7

6.8

6.7

6.8

6.8

189

215

224

278

244

235

185

268

165

210

184

162

999

259

130

136

145

166

160

150

149

189

102

155

145

142

165

191

76

60

O9

Bfi

94

107

92

108

108

O9

88

85

on

79

Q 7

Q 3

11

20

16

14

7.5

26

7.6

12

7.5

12

19

18

6.1

5.3

5.2

8 7

8.7

7.1

5.4

12

5.3

7.0

5.0

6.2

a a

11

2.9

Q n

2.0

4.0

4.0

3.3

2.0

4.0

3.0 3 n

2.0

2.5

4.0

9 n

34

91

49

37

35

47

146

110

42

120

84

121

143

20

QA

23

21

23

22

44

4n

28

8ft

44

42

en

7

11

10

10

9

13

21

14

13

15

22

15

33

78

76

81

Aft

80

A4

79

83

81

83

79

82

an

82

57

57

w

KB

56

R8

56

56

55

R8

KQ

fia

Ka

57

35

35

98

36

3ft

34

34

35

34

35

36

34

34

33

13.4

12.9

12.4

11.9

11.6

12.4

11.3

10.8

10.6

11,3

11.6

11.9

12.9

12.0

8.8

R Q

ft 7

7.3

8.5

8 Q

8 4

7.4

8.3

8 1

7.6

7.3

7 ft

8.3

4.4

4.9

4.7

3.3

5.5

4.7

5.5

3.6

5.7

4.6

3.9

4.0

2.9

2.3

98

104

97

94

89

93

88

84

97

92

97

89

Qj»

89

80

81

81

67

78

83

77

67

76

76

74

67

71

73

ft

A

ft.

31

6

ft

A

4

6

ft

4

4

3

f
4 -^-i -« «<

1950 

1951. 

1952. 

1963 -

1954

1955. .

1956. 

1957. 

1958 . 

1959 

I960. .

1961 

1962. 

1963. 

7.0

6.9

7.0

7.0

6.9

7.0

7.1

7.4

7.2

7.1

7.1

7.2

7.1

7.2

6.6

6.7

6.7

6.6

6.6

6.6

6.8

6.7

6.9

6.7

6.8

6.9

6.9

6.9

6.3

6.3

6.5

6.4

6.4

6.2

6.4

6.3

6.2

6.3

6.6

6.6

6,7

6.5

270

247

290

429

404

307

239

571

195

241

208

298

277

408

159

153

165

214

198

174

178

286

145

173

155

172

192

244

84

58

104

106

102

127

100

127

114

88

88

84

109

89

14

11

18

43

40

25

14

97

11

12

12

21

19

48

7.7

6.7

7.3

14

14

9.4

8.3

31

6.5

8.6

6.8

9.0

10.9

19

3.7

3.0

3.3

4.0

4.0

4.0

3.3

4.3

3.8

2.5

3.0

2.5

4.0

3.0

61

101

48

35

41

30

139

245

67

120

84

121

108

24

32

20

25

25

21

38

53

31

86

44

42

45

10

137

13

12

13

15

19

13

15

22

15

24

79

78

83

85

8(1

83

80

84

82

83

80

83

81

81

57

57

58

59

57

58

56

57

55

59

58

58

58

58

35

36

38

36

34

33

34

35

35

35

38

34

36

34

12.7

12.3

12.4

11.6

11.5

10.9

10.2

10.7

10.4

9.6

12.0

11.8

11.4

10.9

5.9

7.0

6.8

5.4

6.1

7.2

6.4

5.2

6.8

6.0

6.4

5.8

6.4

5.8

0.7

.9

.9

.5

1.3

1.9

2.0

1.3

2.4

1.6

2.8

1.7

1.7

1.3

101

100

94

85

82

85

81

76

86

80

90

89

88

78

50

60

61

46

53

61

57

45

60

55

58

50

56

50

11

127

15

23

25

16

30

19

19

18

21

16

4. Delaware River at Benjamin Franklin Bridge, Philadelphia, Pa., 1950-63

1950 

1951 

1952 

1963. 

1954 

1955 - 

1956 

1957 

1958. 

1959--- .....

I960 

1961 

1962 . .

1963 

6.7

6.9

6.8

6.9

6.8

6.9

7.0

7.7

7.1

7.0

7.0

7.0

7.1

7.2

6.5

6.6

6.6

6.6

6.6

6.5

6.7

6.7

6.9

6.7

6.8

6.8

6.8

6.8

6.0

6.3

6.3

6.4

6.3

6.2

6.5

6.3

6.1

6.3

6.4

6.6

6.5

6.5

309

261

218

453

642

334

252

821

204

255

215

306

287

520

175

163

171

225

238

183

183

337

151

182

161

177

202

270

85

61

101

116

113

130

105

130

115

92

91

85

112

97

23

15

22

50

110

29

15

172

12

16

10

24

18

67

10

8.4

7.1

16

23

11

9.2

44

7.1

10

7.9

9.6

12

22

4.4

3.3

3.9

6.0

4.6

5.1

4.7

6.1

4.1

4.5

4.8

3.5

4.0

4.7

68

97

36

45

49

64

99

79

259

60

122

84

78

82

34

36

25

33

31

32

34

43

60

34

79

46

49

44

14

159

13

13

18

14

25

22

16

20

204

25

79

79

82

83

81

83

79

83

82

83

80

83

79

81

57

57

58

59

57

58

57

57

55

59

58

59

58

58

36

36

38

36

34

33

35

35

35

35

38

34

36

34

10.3

12.4

12.5

9.9

11.0

10.5

9.9

9.6

10,4

9.6

11.6

12.0

11.0

10.3

4.9

6.1

6.2

4.8

5.3

6.6

6 0

4.8

6.2

5.0

6.3

5.6

5.9

5.3

0.0

.6

1.0

.6

1.1

1.5

1.9

1.1

.9

1.7

2.4

1.3

1.5

1.1

87

100

95

76

79

90

78

69

90

81

88

88

86

86

41

53

55

42

45

58

53

41

54

46

57

48

52

46

111?1??111

5. Delaware River at Wharton Street, Philadelphia, Pa., 1950-63

I960 

1951 .......

1952. .. .

1953.. ....

1954. .......

1955 ....

1956 ......

1957 

1958...........

1959.... .......

I960 ........

1961 

1962.... .......

1963...........

6.7

6.8

6.8

6.8

6.8

6.7

7.0

7.5

7.1

6.9

7.0

7.0

7.0

7.1

6.5

6.6

6.6

6.6

6.6

6.5

6.7

6.7

6.9

6.7

6.7

6.7

6.8

6.8

6.2

6.4

6.0

6.4

6.2

6.1

63

6.3

6.1

6.4

6.4

6.2

6.4

6.5

305

327

325

500

666

432

250

646

209

270

229

352

300 740

178

163

171

225

238

183

183

337

151

182

167

198

918

296

81

70

98

109

111

143

104

140

118

95

73

93

104

86

21

24

22

73

123

57

16

116

12

18

14

32

21

137

10

8.4

7.1

16

23

11

9.2

44

7.8

9.7

8.2

12

14

39

4.7

3.0

3.0

4.0

4.0

7.0

5.0

5.3

4.0

3.5

2.0

3.5

5.0

3.0

51

80

57

34

49

43

61

134

67

124

104

93

61

34

36

25

33

32

34

43

60

34

56

47

41

39

11

116

11

11

14

18

19

11

19

12

11

23

80

81

82

84

80

Sfi

80

84

82

84

81

82

81

57

57

58

59

57

58

57

57

55

59

61

59

58

59

37

36

38

37

34

34

35

35

35

36

39

34

36

34

11.5

10.8

11.6

10.4

11.1

a 7

9.0

9.5

10.5 9 1

in Q

11.4

10.3

10.4

4.9

6.1

6.2

4.8

5.3

6.6

6.0

4.8

6.2

5.0

4.7

4.9

4.8

4.2

0.0

.3

.1

.8

1.1

1.2

2.3

1.0

1.4

1.8

1.6

1.1

1.0

.8

91

89

91

85

83

77

71

79

78

69

83

86

90

86

40

48

49

41

41

47

49

38

49

45

43

42

41

37 (t\

V,i:-xV

if

7*

5*i:Vi

8

See footnote at end of table.
TABLE 10. Annual maximum, mean, and minimum of water-quality parameters, Delaware River, 1950-63 1 Continued

Year

Hydrogen ion 

(PH)

Max Median Min

Specific conductance 

I(micromhosat25° C)

Max Mean Min

Chloride (ppm)

Max Mean Min

Suspended sediment 

(ppm)

Max Mean Min

Water temperature 

CP)

Max Mean Min

Dissolved oxygen

Parts per million

Max Mean Min

Percent saturation

Max Mean Min

6. Delaware River at League Island, Philadelphia, Pa., 1950-63

1950. 

1951 

1952 

1953 

1954... _ .....

1955 

1956 

1957 __ ...

1958.. ...

1959.. __ -

I960 __ ...

1961 ........

1962 

1963. 

6.6

7.6

6.8

6.8

6.8

6.7

7.0

7.5

7.1

6.9

6.9

6.9

6.9

6.9

6.4

6.6

6.5

6.5

6.4

6.4

6.7

6.6

6.8

6.7

6.6

6.6

6.7

6.6

6.2

6.3

6.2

6.3

6.2

6.0

6.2

6.3

5.9

6.4

6.5

6.1

6.5

6.4

351

374

362

700

945

639

281

1,180

243

303

250

438

373

1,070

193

197

196

273

354

241

210

502

177

216

185

216

249

392

90

84

107

114

129

161

111

161

132

114

82

101

107

97

26

35

28

128

193

131

18

275

15

22

14

56

29

206

11

11

10

27

49

21

11

86

9.1

12.0

9.5

15

15

47

4.0

4.0

4.0

4.3

6.0

7.0

6.0

8.0

4.5

5.0

3.0

3.5

1.7

3.5

55

90

82

52

58

44

102

177

51

72

100

95

68

31

20

27

28

29

25

36

51

30

41

42

39

42

16

10

7

12

10

14

16

18

13

9

13

14

16

80

80

83

83

80

85

80

84

82

84

an

83

70

81

59

58

58

59

58

59

57

58

56

60

61

61

58

58

38

35

37

37

34

34

36

37

36

36

1O

34

36

35

11.9

10.8

12.1

9.4

10.3

a i

7 8

8.8

10.0

9.2

11.0

10.4

10.3

10.4

4.4

5.1

5.4

4.4

4.9

5.1

4.7

4.0

5.9

5.0

4.6

4.7

4.4

3.5

0.0

.3

1.0

1.2

1.2

2.3

1.4

2.0

1.8

1 8

1.2

.8

.6

94

84

as

73

82

73

65

66

72

79

8Q

81

83

86

37

39

48

39

42

46

42

36

50

46

42

42

38

31

1

1

?,

?,

1

1

1

7. Delaware River at Eddystone, Pa., 1950-63

1950 

1951...........

1952 _ ....

1953 .......

1954...........

1955... _ 

1956..... ......

1957- 

1958. _

1959 

I960.. _ 

1961 

1962.. __ ....

1963 .

6.6

6.8

6.8

7.0

6.7

6.6

7.0

7.4

7.1

6.9

6.9

7.0

6.9

7.0

6.4

6.5

6.5

6.5

6.4

6.4

6.6

6.5

6.8

6.6

6.6

6.6

6.7

6.5

6.0

6.3

6.2

6.3

6.0

6.0

6.1

6.0

6.1

6.3

6.4

6.3

6.4

6.0

556

933

935

1,590

1,860

1,820

320

3,420

290

510

269

1,060

595

2,020

234

261

254

472

619

362

239

1,210

200

268

210

303

315

765

102

83

132

142

150

165

137

192

144

131

122

118

134

107

62

262

220

433

467

22

972

18

60

17

245

86

496

17

31

27

87

126

58

14

312

11

22

41

28

154

4.7

4.0

4.0

6.0

7.0

7.0

7.0

8.0

6.0

5.5

4.0

4.5

7.0

5.0

83

81

57

89

no

7R

203

161

64

O1

104

111

205

56

43

33

35

40

69

63

46

45

55

52

69

25

11

14

16

17

12

32

19

17

18

12

12

16

80

ft!

R9

83

80

86

sn

83

82

85

81

83

70

82

59

58

58

59

58

59

58

58

57

60

62

62

59

58

37

36

38

38

34

34

35

37

37

36

dn

36

37

35

10.6

10.7

11.4

8.1

9.2

8 9

7.3

7 0

9.1

8.9

9

n

11.2

8.4

9 n

4.5

d. 8

5.4

4.0

4.6

4.6

4.5

3.8

5.7

4.9

4.7

5.3

4.5

3.4

0.7

.5

.5

1.4

1.3

1.4

2.5

1.4

2.0

2.2

1 8

2.1

1.4

.6

85

Sfi

8ft

63

74

70

en

58

68

69

QQ

68

75

38

42

46

36

40

42

41

36

50

46

45

48

40

30

8

6

6

13

15

17

30

17

26

24

18

25

18

6
8. Delaware River at Marcus Hook, Fa., 1950-63

I960. _ ....

1961.. __ ....

1952. ___ ....

1953 

1954 

1956. _ ....

1956 

1957. 

1958 

1959 

I960. ... ....

1981 

1982 

1983 

7.2

7.5

7.5

7.1

6.9

6.9

7.2

7.7

7.0

6.8

7.0

6.9

6.7

7.1

6.4

6.6

6.5

6.7

6.5

6.4

6.5

6.3

6.7

6.1

6.5

6.5

6.6

6.4

6.0

6.3

5 7

6.3

5.7

5.2

6.0

5.3

5.5

5.0

6.0

6.0

5.6

5.1

1,000

1,250

1,760

2,550

2,870

3,59,0

fiCU

6,120

370

1,150

393

2,080

1,200

3,860

313

421

342

829

998

581

310

2,330

228

499

250

565

493

1,700

117

92

143

147

1,62

180

143

201

150

139

141

126

141

117

222

872

466

802

848

1,110

129

1,940

33

250

48

560

252

1,460

40

86

51

214

250

124

32

663

15

88

19

120

69

518

5.7

4.7

5.2

7.8

8.6

8.5

6.2

11

6.0

7.4

6.7

5.8

7.5

5.1

123

88

63

120

85

106

130

230

124

73

11Q

93

88

136

51

43

41

48

65

53

56

82

57

51

66

54

42

87

24

13

14

17

21

19

16

33

18

21

20

21

26

28

81

80

82

86

80

86

80

84

82

84

81

83

79

82

59

59

58

59

59

60

58

58

57

60

61

60

59

58

86

35

38

38

34

38

36

38

37

36

39

36

35

34

10.6

10.7

10.7

7.6

9.4

9.0

7.6

7.9

8.8

7.9

9.6

10.7

8.3

8.6

4.6

4.9

5.4

4.2

4.7

5.0

5.0

4.7

5.3

4.8

4.6

5.1

4.4

3.9

1.0

1.6

1.0

1.3

1.9

1.4

2.3

2.5

2.0

2.3

2.2

2.0

1.3

1.4

84

87

82

59

70

76

63

58

71

71

77

82

69

72

39

43

47

38

42

46

46

43

47

46

44

47

39

35

11

18

12

16

20

17

25

33

25

27

27

25

15

16

i Averages of 5-point cross-section samples collected monthly January 1950-December 1963. The figures tabulated under maximum, mean, median, or minimum represent 

the averages of cross sections. The measurements represented in the pH tables are the median of 5 top samples and 3 to 5 bottom samples; in the specific conductance tables, the 

average of 5 top samples; for the chloride tables, the average of 1 to 3 bottom samples; in the suspended-sediment tables, a composite top sample; in the temperature tables, the 

average of 5 top and 3 to 5 bottom samples; for dissolved oxygen, the average of 3 to 5 top samples.

CO

go 

W
TABLE 11. Monthly maximum, mean, and minimum of water-quality parameters, Delaware River, 1949-63 l

Month

Hydrogen ion 

(pH)

Mas Median Min

Specific conductance 

(micromhos at 25° C)

Max Mean Min

Chloride (ppm)

Max Mean Min

Suspended sediment 

(ppm)

Max Mean Min

Temperature (°F)

Max Mean Min

Dissolved oxygen

Parts per million

Max Mean Min

Percent saturation

Max Mean Min

oh£»

00

o

§

3H-l

td

1. Delaware River at Bristol-Burlington Bridge, 1949-63

April .... 

July.. 

September.. ..

November. ... 

December .....

7.3

7.3

7.4

7.3

7.3

7.4

7.5

7.5

7.8 

7.5

7.7 

7.5

6.9

7.1

7.0

6.9

7.0

6.9

7.0

6.9

7.0 

7.0

6.9 

7.1

6.4

6.2

6.5

6.6

6.6

6.6

6.7

6.2

6.6 

6.7

6.5 

6.4

172

188

216

139

156

204

207

255

256 

242

266 

185

140

144

131

98

115

146

176

193

195 

198

181 

168

97

104

85

60

88

84

124

141

136 

136

82 

105

10.1

8.6

12

5.3

8

10

10

17

16 

16

14

8.7

6.2

6.1

5.6

3 9

4.3

5.8

7.4

9.1

8.7 

9.6

8.8 

6.2

3.0

3.3

3.1

2.3

2.9

2.2

4.1

4.1

3.2 

4.2

2.7 

3.7

213

238

332

216

192

113

189

64

205 

170

38

208

45

54

45

54

50

34

41

30

41 

44

22 

47

7

10

8

7

11

9

14

15

7 

8

12 

9

39

41

43

52

67

85

86

85

85 

71

60 

45

36

37

40

48

60

72

80

80

76 

64

53 

42

33

34

34

43

52

65

74

76

70 

49

44 

34

12.1

12.6

13.2

11.6

9.8

8.3

8.2

8.1

8.0 

9.3

11.4 

13.3

in Q

11.3

11.2

10.3

8.9

6.8

5.5

5.7

5.8

7.7

9.1 

10.8

8.7

7.9

8.4

6.7

8.0

3.2

2.3

3.8

2.6 

4.4

7.0 

6.3

99

95

104

98

97

93

102

101

88 

93

98 

106

80

84

86

88

88

77

67

71

72 

79

81 

85

615'

6.'

ftf

81

»

3(

45

31 4'

6! 

5(

2. Delaware River at Torresdale intake, Philadelphia, Pa., 1949-63

April ..........

June

July.... .......

September..... 

October .......

November.... 

December .....

7.2

7.1

7.3

7.3

7.4

7.1

7.2

7.4

7.1 

7.1

7.2 

8.7

6.8

6.8

6.9

6.9

6.9

6.9

6.9

6.8

6.9 

6.8

6.9 

7.0

6.2

6.5

6.4

6.6

6.5

6.6

6.6

6.1

6.3 

6.4

6.5 

6.4

197

190

214

137

170

194

211

273

278 

273

256 

198

144

141

130

100

145

169

190

191 

201

184 

145

102

112

85

57

86

Q1

114

155

141 

146

96 

103

10

11

13

6

10

11

20

17 

26

18 

13

6.7

6.0

5.6

3.7

4 S

6.0

7.6

9.7

9.6 

11.2

9.7 

7.0

4.0

9 7

2.0

2.0

2.5

9 n

4.0

4.0

5.0 

4.0

3.0 

4.0

143

122

245

101

76

76

109

48

85 

109

139 

120

52

49

54

40

28

30

28

29

29 

33

39 

42

13

12

14

10

14

13

9

13

10

7

9 

13

39

41

43

53

65

83

85

85

86 

72

62

47

36

37

39

48

60

72

79

80

76 

65

53 

42

33

34

35

43

53

65

75

75

68

48

45 

35

12.1

12.9

13.4

11.9

9.7

7.7

8.2

7.1

7.5 

9.3

10.7 

12.4

10.5

10.9

10.9

10.1

8.7

6.2

5.3

5.2

5.5 

6.6

8.5 

10.2

7.4

7.4

6.9

8.7

7.8

3.6

2.3

3.5

3.1 

3.3

5.3 

5.1

91

97

104

98

94

83

97

92

95 

97

95 

98

77

80

82

86

85

70

64

64

66 

69

79 

81

52

54

52

76

78

34

29

43

37 

38

50 

41
3. Delaware River at Lettish Avenue, Philadelphia, Pa., 1949-63

April...... 

MSy--_- .... ...

July... ........

September 

November. ... 

December .....

7.6

7.0

7.4

7.2

7.1

7.0

7.0

7.3

6.9 

7.1

7.1 

7.2

6.7

6.8

6.8

6.8

6.8

6.6

6.8

6.8

6.7 

6.7

6.7 

6.7

6.2

6.4

6.2

6.4

6.4

6.3

6.6

6.0

6.6 

6.3

6.3 

6.3

265

206

261

163

178

237

287

483

443

671

455 

216

162

152

137

107

126

166

205

253

267 

284

258 

166

118

111

84

57

89

111

135

163

162 

136

115 

106

14

12

10

6.3 9

13

22

67

61 

97

65 

15

8.5

7.5

6.9

4.2

6.0

7.9

11.4

18

18 

27

21 

9.2

4.0

4.3

2.5

2.5

2.5

3.3

6.5

7.0

6.5 

4.5

4.0 

4.0

115

121

245

101

76

76

109

48

86 

109

139 

120

48

48

56

38

26

31

28

28

28 

31

38 

42

14

15

16

13

13

13

11

1397

8 

17

42

41

44

52

66

84

85

83

85 

73

65 

48

36

37

39

47

59

72

79

80

77 

66

65 

43

34

33

36

44

52

67

76

76

73 

50

47 

37

12.0

12.4

12.3

11.0

9.7

8.7

4.1

6.5

6.6 

6.5

10.2 

12.7

9.6

10.4

9.9

9.5

7.2

3.8

2.4

2.2

2.4 

3.1

4.9 

8.5

7.2

7.6

7.7

7.6

5.5

1.3

.5

.2

.7 

.7

.9 

2.1

90

94

100

92

82

72

49

73

79

57

86 

101

65

77

76

81

71

39

29

28

29 

34

46 

67

52

5£

fif

fM

6£

If73

6 f{

If

4. Delaware River at Benjamin Franklin Bridge, 1949-63

April... 

May.... ..

JllTlft

July 

September....

November _ . 

December..- 

7.7

7.2

7.7

7.2

7.1

7.3

7.4

7.5

7.6 

7.4

7.5 

7.2

6.7

6.8

6.8

6.8

6.8

6.6

6.8

6.7

6.8 

6.7

6.8 

6.9

6.1

6.4

6.2

6.4

6.4

6.3

6.4

6.1

6.3 

6.3

6.3 

6.0

286

222

263

166

193

242

299

503

876 

647

516 

231

172

164

156

111

131

172

219

261

313 

311

283 

175

122

85

102

61

90

113

141

166

169 

135

117 

110

20

13

18

7.0

9.0

14

22

74

172 

115

72 

16

9.9

8.4

8.3

6.1

6.9

9.0

12

20

32 

31

25 

9.9

5.7

3.5

4.6

3.3

3.5

4.1

5.7

6.8

8.1 

5.0

5.1 

6.1

99

112

259

104

79

63

89

39

89 

109

94 

122

51

49

57

44

38

29

33

27

37 

40

41 

49

22

13

22

224

13

18

15

13 9

10 

24

41

43

44

52

65

83

83

84

83 

73

64 

48

37

37

39

48

59

71

79

81

77 

66

55 

44

34

33

36

44

52

66

76

77

69 

60

47 

38

11.6

12.5

12.4

11.1

8.0

6.5

5.2

3.4

6.8 

6.9

10.2 

10.5

8.8

9.5

9.6

9.2

6.6

3.3

2.0

1.9

1.7 

2.5

4.5 

7.9

6.6

7.7

7.6

7.2

5.3

1.1

.6

.0

.0 

.4

.1 

3.5

88

95

100

93

76

74

44

41

69 

63

90 

83

65

70

73

78

65

37

22

23

20 

26

41

65

41

6!

61

fi

ft1

21

5. Delaware River at Wharton Street, Philadelphia, 1949-63

Januwy

April.. .

May

July 

September ... .

November _ . 

December.....

7.5

7.0

7.1

7.0

7.0

6.8

7.0

6.9

6.9 

7.0

7.1 

7.1

6.6

6.6

6.6

6.7

6.7

6.5

6.7

6.7

6.6 

6.6

6.6 

6.6

6.0

5.9

6.3

.6.3

6.3

6.3

6.4

5.9

6.4 

6.3

6.3 

6.0

238

264

295

173

193

247

292

661

692 

646

763 

332

175

170

156

112

136

181

231

283

315 

318

344 

193

109

123

93

68

95

117 i4n

189

171

156

127 

115

18

17

21

9.0

11

15

21

89

123 

116

137

29

9.4

9.6

8.2

4.8

6.0

9.1

13

26

32 

30

37 

12

5.3

4.3

3.6

2.0

3.6

4.0

6.6

8.6

8.5 

6.5

6.0 

4.7

104

93

134

80

61

35

124

64

65 

49

99

78

41

45

47

4n

30

24

38

29

29 

31

38 

39

17

14

16

14

11

11

16

11

6 

15

12 

18

46

41

43

53

63

83

81

85

84

74

66 

60

37

37

40

48

60

72

79

81

78 

67

56 

45

34

34

37

43

54

65

75

77

69 

60

47 

40

11.5

11.6

11.4

10.8

8.8

6.3

3.3

3.0

4.2 

3.8

9.1 

11.5

8.9

9.3

8.8

8.9

6.6

2.3

1.7

1.6

1.4 

2.0

3.1

6.5

5.8

6.5

6.4

6.3

3.4

1.0

.1

.0

.0 

.0

.0 

2.5

86

91

86

90

85

65

39

37

50 

39

75 

91

69

69

67

73

56

26

21

20

17 

22

29 

63

4'

4(

4f

fif V

11(

( (

( 

2

See footnote at end of table.
H

<) 

PQ 

J 

H 

a

1 

il

 ?

I

CQOiOOOO I- COO

i

«i 

OOlMIMIMIMIMOCOOlMO

as «5 «5 to to «i «5 to «5 to to
8. Delaware River at Marcus Hook, Pa., 1949-63

March 

April .

May . 

July 

September ....

November .... 

December.- 

7.7

7.1

7.6

7.1

7.1 

6.8

6.9

7.2

7.6 

7.2

7.4 

7.2

6.6

6.6

6.7

6.7

6.6 

6.4

6.4

6.4

6.6 

6.4

6.4 

6.6

6.6

6.0

6.1

6.4

6.9 

6.0

6,2

6.6

6.9 

5.1

6.0

5.7

4.300

2,380

462

201

316 

979

2,110

5.810

6,370 

6,500

6,970 

3,730

672

394

207

167

194 

325

699

1,340

1,340 

1,840

1,770 

629

156

158

126

89

138 

139

224

226

207 

169

194 

139

1,460

43

43

11

16 

216

530

1,720

1,560 

1,940

1,920 

1,030

138

17

12

7.8

9.7 

40

116

349

344 

581

616 

153

7.8

6.2

6.2

4.7

6.2 

6.2

13

14

10

7.7

8.6 

7.3

136

124

114

78

64 

69

67

94

130 

143

230 

86

77

73

69

61

39 

33

36

49

44 

64

71 

60

33

27

38

34

17 

19

13

18

14

27

39 

34

46

41

45

66

64 

83

84

86

86 

73

64 

50

38

39

41

49

60 

72

80

81

77 

67

56 

46

34

34

36

46

55 

65

76

77

69 

47

50 

41

9.6

10.7

10.7

10.1

6.7 

4.6

3.6

3.1

4.7 

6.3

6.2 

10.6

7.6

7.8

8.1

7.8

4.2

2.7

2.3

2.1

2.3 

2.9

3.7 

6.1

6.0

6.3

6.3

5.6

1.9 

1.3

1.0

1.0

1.0 

1.0

1.2 

2.7

76

82

85

87

64 

51

43

39

55 

54

48 

84

56

59

62

67

31 

30

29

26

28 

30

35 

51

43

47

46

50

20 

15

12

12

12 

11

12 

43

1 Averages of cross-section samples collected monthly August 1949-December 1963. The figures tabulated under maximum, mean, median, or minimum represent the average 

of cross sections. The measurements represented in the pH tables are the median of 5 top samples and 3 to 6 bottom samples; in the specific conductance tables, the average of 

i t-oi, ~p!^, iai ILi, oLIoride tables, the average of 1 to 3 bottom samples; in the suspended-sediment tables, a composite top sample; in the temperature tables, the average of 5 

top and 3 to 5 bottom samples; for dissolved oxygen, the average of 3 to 5 top samples.
O52 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

micromhos; however, when the conductance exceeds 600 micromhos 

(which it did in nearly one-quarter of the samples), the conductance 

on the New Jersey side often exceeds that on the Pennsylvania side.

Because salt water is heavier than fresh water, ocean water may 

move up the estuary along the river bottom with the fresher water 

overriding the tongue of salt water and eroding it. This overriding 

happens in some parts of the estuary at some times, but in the river 

between Trenton and Marcus Hook such a salt tongue has not been 

observed. The salinity of the bottom samples at Marcus Hook is 

generally 5-10 percent greater than that of the top samples, but at 

upstream locations there is no significant difference in salinity between the top and bottom water. Occasionally top samples will have 

a slightly greater salinity than bottom samples. This salinity is 

presumably a temporary result of salt water, which is sometimes 

warmer and therefore, less dense than the cooler bottom water.

In any cross section the temperature variations are generally less 

than 1°F. Top and bottom samples normally have the same pH, 

within 0.2 pH units, but occasionally large differences have been 

observed. The bottom samples on the right and left sides most frequently deviate in pH from the average for the cross section; this 

deviation is possibly the effect of pollution, tributary streams, or 

ground water inflow.

During most of the period covered by this report (1949-63), dissolved oxygen was determined on top samples only. Dissolved-oxygen concentration at Bristol is nearly uniform in the top cross section. From Lehigh Avenue to Eddystone the oxygen concentration 

is more depleted on the Pennsylvania side of the River than on the 

New Jersey side, the difference averaging 0.7 ppm. At Marcus Hook 

the dissolved oxygen is approximately 1.0 ppm lower on the Pennsylvania side.

On the twice-daily flood tide, salt water flows upstream, and the 

salinity at each sampling station increases. The maximum salinity 

occurs at high-water slack, the time at which the flood current reverses and becomes an ebb current. During the ebb tide the salty 

water is swept seaward by the downstream flow of fresher water, 

and the increase in fresh water causes the salinity at any sampling 

station to reach a minimum at low-water slack. Thus, the salinity 

at any location in the estuary each day goes through two maxima, 

not necessarily identical, and two minima, also not necessarily identical.

Onshore winds blow sea water shoreward and may raise the sea 

level at the south of Delaware Bay. This rise in sea level causes 

water to move upriver and salinity to increase in the lower estuary. 

Offshore winds may cause a decrease in sea level and a corresponding
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK Q53

flow of water seaward throughout the river and estuary, thereby 

decreasing the salinity; however, when sea levels return to normal 

as the offshore winds subside, ocean water flows into the estuary replacing that which had been blown out. The end result is, therefore, 

saltier water in the estuary. The magnitude of these changes in 

salinity depends upon the force and direction of the wind and its 

duration.

The samples referred to in this report were taken at random times 

with respect to stage of tide, tidal range, and sea level. In the present sampling program specific conductivity, pH, temperature, and 

dissolved oxygen are recorded continuously at several locations. As 

a result, there soon will be a more comprehensive knowledge of 

water-quality changes and of the precise times that they occur. This 

knowledge will help in evaluating the relative effects of such factors 

as sea level and fresh-water discharge.

SUMMARY AND CONCLUSIONS

That reach of the Delaware River from Bristol to Marcus Hook 

was sampled in detail once each month during the 14 years from 

August 1949 to the end of 1963. This period embraces a range of 

fresh-water inflow conditions. The 50-year average discharge at 

Trenton is 11,830 cfs; the largest annual mean discharge in the 

14-year period was 150 percent as large as the 50-year average, and 

the smallest annual mean discharge 60 percent as large. In general, 

the salinity of this reach of the river is influenced by the discharge. 

In the lower half of this reach, the concentration of dissolved solids can 

be estimated from the measured specific conductance (expressed in 

micromhos at 25°C). For concentrations less than 200 ppm, the 

dissolved-solids concentration (in ppm) is approximately 16 ppm 

plus 52 percent of the specific conductance. From 200 to 2,500 ppm, 

the dissolved-solids concentration is 60 percent of the specific conductance at 25 °C.

Although the annual mean discharge in 1952 was substantially 

larger than in any other year in the 1950-1963 period, this was not 

the year in which the river water contained the lowest concentration 

of dissolved solids. The river water was the least saline in 1958. 

The highest salinities were observed in 1954, 195Y and 1963. In each 

of these years the annual mean discharge was low, and the discharge 

for July, August, and September was also low. In 1953 and 1962 

the July to September discharge was also low and the salinity high, 

but not as high as in 1954,195Y and 1963.

The dissolved-solids concentration in the river water is lowest in 

the spring and highest in late summer and early autumn because the
O54 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

fresh-water discharge is greatest in March, April, and May and least 

in August, September, and October. For example, in March, April, 

and May the mean dissolved-solids concentration is 76 ppm at Bristol, and 112 ppm at Marcus Hook. In August and September the 

mean is 117 ppm at Bristol and 804 ppm at Marcus Hook. There 

is a greater variation of concentrations in the estuary at Marcus 

Hook than at Trenton, as a result of tidal action. The greatest 

dissolved-solids concentrations represented by these monthly samples were 160 ppm at Bristol and 4,000 ppm at Marcus Hook.

The chloride concentration at Marcus Hook exceeded 100 ppm 

24 percent of the time and 10 ppm 70 percent of the time. At Benjamin Franklin Bridge, however, 100 ppm chloride was exceeded only 

2 percent of the time and 10 ppm less than 40 percent of the time. 

At Chester, for a 31-year period, 250 ppm chloride was exceeded 

10 percent of the time, 60 ppm 20 percent of the time, and 15 ppm 

50 percent of the time.

The worst salinity invasions of the Delaware River were in 1949, 

1953, 1954, 1957 and 1963. Significant increases in salinity were 

observed upstream from Lehigh Avenue, Philadelphia, Pa. In these 

5 years the mean monthly discharge at Trenton for each month from 

July to October was less than 4,000 cfs; however, from July to September, 1962, the mean monthly discharge at Trenton was also less 

than 4,000 cfs each month, but the annual mean dissolved-solids concentration was not as great as in the 5 years referred to above.

Perhaps the major factor controlling the salinity of this reach of 

the estuary is the amount of fresh-water discharge into the estuary, 

especially in July, August, and September. For example, in those 

years in which the mean, monthly discharge during July, August, and 

September exceeded 4,000 cfs at Trenton, the average annual dissolved-solids concentration of the river water at Benjamin Franklin 

Bridge, Philadelphia, was approximately 100 ppm and varied little 

with change in discharge. For a mean monthly discharge of less 

than 4,000 cfs in these 3 months, the dissolved-solids concentration 

at the Benjamin Franklin Bridge is greater than 100 ppm, and the 

concentration increases as the discharge becomes smaller. At Marcus Hook the annual mean dissolved-solids concentration is 180-300 

ppm and is relatively uninfluenced by variation in water discharge 

if the discharge rate at Trenton exceeds 5,000 cfs. At lower rates 

of flow the mean annual dissolved-solids concentration increases as 

the July-August-September discharge decreases. The principal 

source of fresh water is the Delaware Kiver at Trenton, although 

some fresh water comes also from the Schuylkill Eiver and other 

tributaries. A high rate of fresh-water discharge flushes out the
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK O55

river and opposes factors such as high sea level or onshore winds 

that favor the intrusion of salt water from the sea.

The median pH is 6.9 in the reach of the river from BristolBurlington Bridge to Torresdale, 6.6 from Lehigh Avenue to League 

Island, and 6.5 from Eddystone to Marcus Hook. Water temperatures range from 33° to 86°F, the median temperature being near 

58°F.

Dissolved oxygen is brought into the estuary with fresh water at 

Trenton, by tidal water in the lower estuary, by photosynthesis, and 

through the air-water interface. This oxygen is consumed in the 

oxidation of organic pollutants, a process which proceeds faster in 

the warm water of summer than in the cold water of the other 

seasons. Dissolved oxygen is at a lower concentration from May or 

June to October or November than during the winter months. As 

the water moves downstream, dissolved oxygen is consumed, and its 

concentration generally reaches a minimum near Wharton Street but 

increases slightly from there to Marcus Hook.

Owing to photosynthesis, the concentration of dissolved oxygen is 

greater in daylight than at night. Since the samples of water were 

always taken in daytime, the daily mean dissolved-oxygen concentrations were probably lower than those reported in the plots and 

tables. There is no evidence of a trend in dissolved-oxygen concentrations over the 14-year period, except that the lowest minimum 

concentrations were those of the July to November 1950 period in 

the reach of the river from Wharton Street to League Island. At 

Benjamin Franklin Bridge one-half of the samples were more than 

55 percent saturated with dissolved oxygen, one-third less than 30 

percent saturated.

When streamflow is high, sediment is picked up by the moving 

water and carried downstream, so that the sediment concentration 

increases from Bristol to Marcus Hook. Dredging also stirs up 

sediment and increases its concentration in the water at and downstream from the dredging area.

In the reach of river which includes the eight sampling stations, 

the water quality generally varied little in the cross section of the 

river. In most of this reach of river most of the time, the specific 

conductance of the water on the Pennsylvania side may be 5 percent 

greater than on the New Jersey side, and the dissolved-oxygen concentration about 0.7 ppm less on the Pennsylvania side than on the 

New Jersey side, but temperature and pH are uniform. This situation may be the result of a greater concentration of industries and 

people on the Pennsylvania side with a consequent greater flow of 

wastes to the river. The analyses presented in this report, however,
056 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

are of the cross section, including the channel and therefore are 

representative of most of the water flowing past each of the eight 

sampling stations.

The cross-sectional variation in water quality at Marcus Hook is 

somewhat greater than at the upstream stations. Here the bottom 

samples usually have specific conductances 5-10 percent greater than 

the top samples, and dissolved-oxygen concentrations are about 1.0 

ppm lower on the Pennsylvania side. Most of the time the conductance of water on the Pennsylvania side is slightly greater than that 

of the water on the New Jersey side, but this situation is often reversed when the dissolved-solids concentration of the water is greater 

than 360 ppm.

At all stations the water quality varies twice daily with the ebb 

and flood of the tide. The salinity is greatest at time of slack water 

following high tide and lowest at the time of the slack water following low tide. The maxima and minima in dissolved-oxygen concentration often occur at slack water also, but whether the concentration 

of dissolved oxygen increases or decreases as the tide floods depends 

upon the dissolved-oxygen concentration in the reach of stream 

directly downstream from the sampling station.

This report summarizes the results of monthly sampling over a 

14-year period. During most of this period, there were few instruments to continuously record water-quality data.

In 1955 the U.S. Geological Survey installed the first recording 

instrument in the estuary for continuously measuring and recording 

specific conductance, and in 1959 dissolved-oxygen and temperature 

recorders were installed. In 1964, in the reach of the estuary between Bristol and Marcus Hook, temperature was continuously recorded at or near four of these monthly sampling stations, specific 

conductance at three, dissolved oxygen at four, pH at one, and turbidity at one. In addition, tidal-flow volume is measured at one 

point (Palmyra, N.J.), and tide gages record water-level fluctuations 

at about a dozen locations in this reach (Miller, 1962). Hand sampling is still required to establish a relation between the cross section 

and the continuously recorded values to check on the accuracy of the 

instrument record and to collect samples for types of analyses which 

have not yet been adapted to recording instruments such as biochemical-oxygen demand. Obviously, in the future the greater frequency of measurement by automatic instruments will give more 

information about the range in water-quality characteristics and 

determine more precisely when variations occur.

Although a much more detailed description of water quality in 

this reach of the estuary will soon become available through the use 

of recording instruments, it is nevertheless useful now to summarize
DELAWARE RIVER WATER, BRISTOL TO MARCUS HOOK O57

these monthly analyses for the period 1949-63. This period includes 

a range of conditions and exhibits the extent to which water-quality 

parameters varied with change in hydrologic and environmental 

conditions. This compendium of water-quality data is useful as an 

explicit statement of water quality during the 14-year period and is 

valuable for directing attention to water-quality problems, for selecting instrument sites, and for making comparative studies with the 

more detailed information which is already being obtained with the 

aid of recording instruments.

SELECTED REFERENCES

Cohen, Bernard, and McCarthy, L. T., Jr., 1962, Salinity of the Delaware River 

estuary: U.S. Geol. Survey Water-Supply Paper 1586-B, p. 47.

Durfor, C. N., and Anderson, P. W., 1963, Chemical quality of surface waters 

in Pennsylvania: U.S. Geol. Survey Water-Supply Paper 1619-W, p. 50.

Durfor, C. N., and Keighton, W. B., 1954, Chemical characteristics of Delaware 

River water Trenton, New Jersey, to Marcus Hook, Pennsylvania: U.S. 

Geol. Survey Water-Supply Paper 1262, p. 173 [1955].

Ketchum, B. H., 1951a, The exchanges of fresh and salt waters in tidal estuaries: Jour, of Marine Research, Sears Foundation, v. 10, no. 1, p. 18-38.

 I951b, The flushing of tidal estuaries: Sewage and Industrial Wastes, 

v. 23, no. 2, p. 198-208.

McCarthy, L. T., Jr., and Keighton, W. B., 1964, Quality of Delaware River 

Water at Trenton, New Jersey: U.S. Geol. Survey Water-Supply Paper 

1779-X.

Miller, E. G., 1962, Observations of tidal flow in the Delaware River: U.S. 

Geol. Survey Water-Supply Paper 1586-C, p. 8-26.

U.S. GOVERNMENT PRINTING OFFICE : 1965 O 770-402