Fecal–Indicator Bacteria in the

Allegheny, Monongahela,

and Ohio Rivers, near Pittsburgh,

Pennsylvania, July-September 2001

by John W. Fulton and Theodore F. Buckwalter

U.S. Department of the Interior

U.S. Geological Survey

In cooperation with the Allegheny County Health Department

Scientific Investigations Report 2004-5009
U.S. Department of the Interior

Gale A. Norton, Secretary

U.S. Geological Survey

Charles G. Groat, Director

U.S. Geological Survey, Reston, Virginia: 2004

For sale by U.S. Geological Survey, Information Services

Box 25286, Denver Federal Center

Denver, CO 80225

For more information about the USGS and its products:

Telephone: 1-888-ASK-USGS

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

endorsement by the U.S. Government.

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

reproduce any copyrighted materials contained within this report.
iii

Contents

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

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

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

Description of Study Area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Water-Quality Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Previous Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Ohio River Valley Water Sanitation Commission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

U.S. Geological Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Local Efforts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Related Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Sources of Bacteria. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Point Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Nonpoint Sources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Fate and Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Study Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Site Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Sampling Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Sampling Protocol Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Streamflow Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Water-Quality Sampling Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Quality Assurance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Occurrence and Distribution of Fecal-Indicator Bacteria. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Bacteria Concentrations and Distributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Weather Effects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Monongahela River Subbasins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Allegheny River Subbasins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Ohio River Subbasins. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Comparison to Water-Quality Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Load Estimates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Summary and Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

References Cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Appendixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Figures

1. Map showing study area and location of sampling sites on the Allegheny, Monongahela,

 and Ohio Rivers region near Pittsburgh, Pennsylvania . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

2. Graph showing cumulative percentage of discharge and stream cross section

 in an example of an equal discharge incremental sample. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

3. Rivercross-sectionandstream-velocityprofilegeneratedfromacousticDopplercurrent

 profiler, Monongahela River at Braddock, Pennsylvania (03085000), August 28, 2001 . . . . . . . . 10

4. Hydrograph from the streamflow-gaging station on the Ohio River at Sewickley,

nearPittsburgh,Pa.,on August 4-7, 2001, prior to the August 8 wet-weather event. . . . . . . . . . . 10
iv

Figures—Continued

5-7. Boxplots showing fecal-indicator bacteria colonies in composite samples collected

 on the Allegheny, Monongahela, and Ohio Rivers near Pittsburgh, Pa., during:

5. Dry weather, 2001. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

6. Mixed weather, 2001. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

7. Wet weather, 2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

8-11. Maps showing:

8. Concentrations of fecal-indicator bacteria during dry weather on August 7, 2001,

 from five sites on the Allegheny, Monongahela, and Ohio Rivers near Pittsburgh,

 Pennsylvania . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

9. Concentrations of fecal-indicator bacteria after wet weather on August 8, 2001,

 from five sites on the Allegheny, Monongahela, and Ohio Rivers near Pittsburgh,

 Pennsylvania . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

10. Land cover of five subbasins within the Allegheny, Monongahela, and Ohio Rivers

 region, Allegheny County, Pennsylvania. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

11. Distribution of combined sewer overflows (CSOs) and sanitary sewer overflows

 (SSOs) near Pittsburgh, Pennsylvania . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Tables

1. Description of sampling sites on the Allegheny, Monongahela, and Ohio Rivers

near Pittsburgh, Pennsylvania. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2. Comparison of bacteria concentrations in discrete and composite samples collected

from the Ohio River at Sewickley, Pennsylvania . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3. Concentrations of field replicate samples for fecal-indicator bacteria, Allegheny and

Monongahela Rivers, July-September 2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

4. Summary of concentrations of fecal-indicator bacteria that are above or below

water-quality criteria for dry-, mixed-, and wet-weather events, July-September 2001,

Allegheny County, Pennsylvania . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

5. Summary statistics for streamflow, temperature, and concentrations of fecalindicator bacteria for the five sampling sites within the Three Rivers region, Pa.,

July-September 2001. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

6. Concentrations of fecal-indicator bacteria in composite samples collected during

wet-weather events, Allegheny, Monongahela, and Ohio Rivers near Pittsburgh,

Pennsylvania, August-September 2001. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

7. Statistically significant relations for fecal-indicator bacteria for dry-, mixed-,

 and wet-weather samples July-September 2001, Allegheny County, Pa. . . . . . . . . . . . . . . . . . . . . 24

8. Estimated daily loads of fecal-indicator bacteria within the Allegheny, Monongahela,

and Ohio Rivers near Pittsburgh, Pennsylvania, July-September 2001. . . . . . . . . . . . . . . . . . . . . . . . 25

APPENDIXES

1. Summary of streamflow and water-quality samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
v

Conversion Factors and Abbreviations

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

°F = (1.8 ⋅ ° C) + 32

Concentrations of bacteria are given in colonies per 100 milliliters (col/100 mL), which is the

same as colony forming units per 100 milliliters (CFU/100 mL).

Other abbreviations used in report:

ACHD Allegheny County Health Department

ADCP Acoustic Doppler current profiler

cm centimeter

CSOs Combined Sewer Overflows

CWA Clean Water Act

E. coli Escherichia coli, a fecal-indicator bacterium

EDI equal discharge increment

FC Fecal coliform

L liter

m meters

mL milliliters

MPN Most probable number

NASQAN National Stream Quality Accounting Network

NAWQA National Water-Quality Assessment

NWS National Weather Service

ORSANCO Ohio River Valley Water Sanitation Commission

PaDEP Pennsylvania Department of Environmental Protection

Q Discharge

QAPP Quality Assurance Project Plan

SSOs Sanitary Sewer Overflows

TMDL Total Maximum Daily Load

USACE U.S. Army Corps of Engineers

USEPA U.S. Environmental Protection Agency

USGS U.S. Geological Survey

WQS Water-Quality Standard

WWTP Wastewater-treatment plant

Multiply By To obtain

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

square mile (mi2) 2.590 square kilometer (km2)

cubic foot per second (ft3

/s) 0.02832 cubic meter per second
vi
Fecal-Indicator Bacteria in the Allegheny, Monongahela,

and Ohio Rivers, near Pittsburgh, Pennsylvania,

July-September 2001

by John W. Fulton and Theodore F. Buckwalter

Abstract

This report presents the results of a study by the Allegheny

County Health Department (ACHD) and the U.S. Geological

Survey (USGS) to determine the concentrations of fecal-indicator bacteria in the Allegheny, Monongahela, and Ohio Rivers

(Three Rivers) in Allegheny County, Pittsburgh, Pa. Waterquality samples and river-discharge measurements were collected from July to September 2001 during dry- (72-hour dry

antecedent period), mixed-, and wet-weather (48-hour dry antecedent period and at least 0.3 inch of rain in a 6-hour period)

conditions at five sampling sites on the Three Rivers in Allegheny County. Water samples were collected weekly to establish

baseline conditions and during successive days after three wetweather events.

Water samples were analyzed for fecal-indicator

organisms including fecal-coliform (FC) bacteria, Escherichia

coli (E. coli), and enterococci bacteria. Water samples were

collected by the USGS and analyzed by the ACHD Laboratory.

At each site, left-bank and right-bank surface-water samples

were collected in addition to a composite sample (dischargeweighted sample representative of the channel cross section as

a whole) at each site. Fecal-indicator bacteria reported in bank

and composite samples were used to evaluate the distribution

and mixing of bacteria-source streams in receiving waters such

as the Three Rivers.

Single-event concentrations of enterococci, E. coli, and

FC during dry-weather events were greater than State and

Federal water-quality standards (WQS) in 11, 28, and

28 percent of the samples, respectively; during mixed-weather

events, concentrations of fecal-indicator bacteria were greater

than WQS in 28, 37, and 43 percent of the samples, respectively; and during wet-weather events, concentrations of fecalindicator bacteria were greater than WQS in 56, 71, and

81 percent of samples, respectively.

Single-event, wet-weather concentrations exceeded

those during dry-weather events for all sites except the

Allegheny River at Oakmont. For this site, dilution during wetweather events or the lack of source streams upgradient of the

site may have caused this anomaly. Additionally, single-event

concentrations of E. coli and FC frequently exceeded the WQS

reported during wet-weather events.

It is difficult to establish a short-term trend in fecalindicator bacteria concentrations as a function of time after a

wet-weather event due to factors including the spatial

variability of sources contributing fecal material, dry-weather

discharges, resuspension of bottom sediments, and flow

augmentation from reservoirs. Relative to E. coli and

enterococci, FC concentrations appeared to decrease with time,

which may be attributed to the greater die-off rate for FC

bacteria.

Fecal-indicator bacteria concentrations at a site are

dependent on the spatial distribution of point sources upstream

of the station, the time-of-travel, rate of decay, and the degree

of mixing and resuspension. Therefore, it is difficult to evaluate

whether the left, right, and composite concentrations reported

at a particular site are significantly different. To evaluate the

significance of the fecal-indicator bacteria concentrations and

turbidity reported in grab and composite samples during dry-,

mixed-, and wet-weather events, data sets were evaluated using

Wilcoxon rank sum tests. Tests were conducted using the fecalindicator bacteria colonies and turbidity reported for each

station for a given weather event. For example, fecal coliform

counts reported in the left-bank sample were compared against

the right-bank and composite samples, respectively, for the

Ohio River at Sewickley site during dry-, mixed-, and wetweather events.

The statistical analyses suggest that, depending on the

sampling site, the fecal-bacteria concentrations measured at

selected locations vary spatially within a channel (left bank

compared to right, right bank compared to composite). The

most significant differences occurred between fecal-indicator

bacteria in the left bank compared to composite and right bank

compared to composite samples (p-values = 0.003 to 0.1),

suggesting that during some wet- and dry-weather events, the

mixing of source streams and the receiving water is incomplete. Turbidity (p-values = 0.003 to 0.1) and enterococci

(p-values = 0.007 to 0.02) most frequently demonstrated a

correlation between sample locations (left bank versus

composite). Correlations between left-bank and right-bank

samples were rare.
2 Fecal-Indicator Bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-Sept. 2001

Introduction

Fecal-indicator bacteria in surface water collected from

the Allegheny, Monongahela, and Ohio Rivers (Three Rivers)

near Pittsburgh, Pa., periodically exceed state and Federal

water-quality standards (WQS) for recreational waters

(Siwicki, 2002). Because individual pathogens are difficult to

measure directly (Chapra, 1997, p. 504), monitoring programs

commonly rely on the detection of indicator organisms to serve

as a surrogate of water quality. If indicator organisms are

present, it is assumed more harmful pathogens such as bacteria,

viruses, and protozoans may coexist in the water body.

Pathogens may be present in recreational waters or

drinking-water supplies. Exposure to pathogens in water can

have adverse effects on humans. During contact with

recreational water, excessive amounts of bacteria can result in

an increased risk of gastrointestinal, respiratory, eye, ear,

throat, and skin diseases. Drinking water containing pathogens

also may pose a risk, but public-water supplies must pass state

drinking-water standards prior to distribution. Most bacteria

can be removed by the use of chlorine, ion exchange, filtration,

and reverse osmosis, but treatment costs can be excessive. The

protozoans Cryptosporidium parvum and Giardia lamblia are

resistant to chlorine and require supplemental filtration. Filterfeeding shellfish, including clams, oysters, and mussels,

concentrate microbial contaminants in their systems and may

be harmful to humans when consumed raw or uncooked (U.S.

Environmental Protection Agency, 2001).

Fecal-indicator bacteria include a variety of coliform

bacteria and streptococcus bacteria. Traditionally, total

coliform is the most widely used parameter for monitoring;

however, its use is problematic becauseof nonfecal coliform

bacteria. Organisms more indicative of intestinal contamination such as enterococci, Escherichia coli (E. coli), and fecal

coliform (FC) are preferred. Each can be sampled and

quantified using standard methods and are relatively abundant

in human and animal waste. Because the die-off rates for

enterococci and E. coli are less than that of FC, they provide a

better measure of the risk of gastrointestinal illness related to

recreational contact (U.S. Environmental Protection Agency,

2001).

Federal regulations require public notice when sewer

overflows and runoff increase the likelihood of river

contamination. Since 1995, the Allegheny County Health

Department (ACHD) has issued river-water advisories to warn

of possible river contamination and to caution people to limit

contact with river water when boating, fishing, skiing,

swimming, or engaging in other river recreational activities.

An advisory does not prohibit nor discourage river recreational

activities; instead, it is intended to inform the public when river

water may be contaminated so that precautions can be taken to

minimize water contact. Advisories are issued during the

summer river-recreation season, which lasts from May 15 to

September 30, when sewer overflows and storm runoff increase

the likelihood of river contamination. During the summer of

2000, when precipitation was above normal, 13 advisories

were issued, lasting 71 out of a total of 138 days.

Bacteria concentrations in the Three Rivers need to be

measured to alert users of potential pathogen concentrations.

The U.S. Geological Survey (USGS) in cooperation with the

ACHD began a project in July 2001 to assess fecal-indicator

bacteria contamination of the Three Rivers in Allegheny

County, Pa. The project was supported using funds allocated

through Section 104(b)(3) of the Clean Water Act (CWA) and

administered by the U.S. Environmental Protection Agency

(USEPA) and the Pennsylvania Department of Environmental

Protection (PaDEP).

Purpose and Scope

This report (1) establishes sampling protocols for

monitoring receiving water; (2) presents the E. coli,

enterococci, and FC bacteria data collected from five sites in

the Three Rivers from July to September 2001; (3) evaluates

the distribution of bacteria in receiving water; (4) determines

the effects of wet weather on bacteria colonies; (5) compares

the bacteria data to WQS; and (6) estimates daily loads of

fecal-indicator bacteria. Water-quality samples were collected

and streamflow was measured during dry-, mixed-, and wetweather conditions at five sampling sites in the Three Rivers in

Allegheny County. Samples were collected weekly to establish

baseline conditions and during successive days after three wetweather events. The samples after wet-weather events were

collected on the following dates: August 8, 9, and 10; August

29 and 30; and September 25, 26, 27, and 28.

Description of Study Area

The study area includes portions of the Allegheny,

Monongahela, and Ohio Rivers, which are the large rivers

entering and exiting Allegheny County (fig. 1). Allegheny

County has an area of about 730 mi2. Pittsburgh, the county

seat, is near the center of the county, where the Allegheny and

Monongahela Rivers join to form the Ohio River.

Allegheny County is in a rugged section of the

Allegheny Plateau Physiographic Province. Stream erosion has

created a complexly dissected area having as much as 650 ft of

relief between hilltops and valley bottoms. The tributary

streams generally lie in V-shaped valleys, and their gradients

are much steeper than those of the major streams. These steep

gradients facilitate rapid urban runoff after precipitation.

The 2000 census listed 1,281,666 people in the county

and 334,563 in the city of Pittsburgh (U.S. Census Bureau,

2003, accessed April 29, 2003).

Annual precipitation for Pittsburgh averages 37 in. The

Allegheny River serves as the source of water supply for the

city of Pittsburgh. The Monongahela River is the source of

water for the Pennsylvania American Water Company, which

serves large areas of Allegheny County to the south of the city

of Pittsburgh. Several municipalities pump water from wells

adjacent to the Three Rivers for water supply.
Introduction 3

Figure 1. Study area and location of sampling sites on the Allegheny, Monongahela, and Ohio Rivers region near

Pittsburgh, Pennsylvania.
4 Fecal-Indicator Bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-Sept. 2001

Water-Quality Criteria

The PaDEP (25 Pa. Code §93.7) has established the

following WQS for bacteria: from May 1 through

September 30, FC shall not exceed a geometric mean of

200 col/100 mL from five consecutive samples in a 30-day

period. From October through April, FC shall not exceed

2,000 col/100 mL. Pennsylvania presently (2004) lacks

recreational water-quality criteria for E. coli and enterococci in

surface water. The USEPA (1986) has issued recommended

criteria for E. coli of 126 col/100 mL and enterococci of

33 col/100 mL in recreational waters. Both are represented as a

geometric mean based on not less than five samples equally

spaced over a 30-day period.

Given the objectives of this project, the collection of five

samples, equally spaced over a 30-day period, was not

attempted. Rather, the project was designed to measure the

effects of dry- and wet-weather events on the quality of the

receiving waters within the region. Because the timing of dryand wet-weather events did not coincide with regular, weekly

sample events, the WQS specified above were used as a metric

and not a compliance criteria. Town (2001) adopted this

modification of the 1986 USEPA criteria for other fecalindicator studies in recreational waters in Pennsylvania.

Previous Work

Federal, local, and private agencies have conducted

bacteria monitoring of the Three Rivers. On the basis of

historical data, the highest concentrations of FC generally are

during the summer months after storm events, when the WQS

are most stringent for the Allegheny and Monongahela Rivers.

A review of past and present programs follows.

Ohio River Valley Water Sanitation Commission

(ORSANCO)

Since 1992, bacteriological monitoring in the Ohio

River has been conducted by ORSANCO, an interstate

commission representing the Federal government and eight

member states that border the Ohio River Basin.

From May through October each year, surface-water

grab samples are collected at mid-stream at river mile 4.3

(distance in miles measured downstream from the confluence

of the Allegheny and Monongahela Rivers in Pittsburgh) at a

frequency of five per month. From 1992 to 1999, samples were

analyzed for FC only; analysis for E. coli started in 2000.

During the period from 1992 through 2001, the minimum,

maximum, and median concentrations of FC were 4; 35,000;

and 330 col/100 mL, respectively. The minimum, maximum,

and median concentrations of E coli were 150; 27,000; and

150 col/100 mL, respectively (Ohio River Valley Water

Sanitation Commission, oral commun., 2002).

U.S. Geological Survey

The USGS participated in two programs in the Three

Rivers area near Pittsburgh, Pa., that included sampling and

analysis for indicator bacteria.

• From 1976 through 1989, USGS partnered with the

USEPA to operate a surveillance network at the

Allegheny River at New Kensington, Pa., and Monongahela River at Braddock, Pa. The same sites were

sampled from 1989 through 1994 as part of another

USGS program, the National Stream Quality Accounting Network (NASQAN). The sites were operated in

1995 as part of the USGS National Water-Quality

Assessment (NAWQA) Program. During each program, surface-water samples were collected midstream at a frequency of one per month or quarterly and

analyzed for concentrations of FC and fecal streptococci. From 1976 through 1995, the median concentration of FC at New Kensington was 225 col/100 mL.

The median concentration of FC at Braddock was

1,200 col/100 mL.

• From 1980 through 1995, 72 percent of the FC samples

collected at New Kensington from May through September exceeded the WQS of 200 col/100 mL; only

2.3 percent of the samples collected from October

through April exceeded the 2,000 col/100 mL WQS.

Similarly, 97 percent of the samv ples collected at

Braddock from May through September exceeded

200 col/100 mL; only 7.8 percent of the samples

collected from October through April exceeded

2,000 col/100 mL (U.S. Geological Survey, 2002).

The above data show that concentrations of fecalindicator bacteria exceeded WQS established by PaDEP and

USEPA; however, the influence of dry- and wet-weather events

was not a focus of these efforts.

Local Efforts

Bacteria monitoring has been implemented by a variety

of local groups, including water companies, ACHD, and

3 Rivers – 2nd Nature, STUDIO for Creative Inquiry (3R2N),

part of the College of Fine Arts of Carnegie Mellon University.

The bacteria data collected by the water companies and ACHD

are unpublished. 3R2N issues annual reports summarizing

water-quality data for the Three Rivers and selected tributary

sites. The program is a multiyear effort focusing on different

navigation pools within the Three Rivers region. Sample sites

are dependent on public access and inflow points discharging

to the Three Rivers. Water-quality constituents sampled by this

program include total coliform, E. coli, enterococci, pH,

temperature, specific conductance, and dissolved oxygen.

In addition to water-quality sampling, the group has

attempted to establish a relation between historical use and

human activities that has influenced changes in the river system
Introduction 5

over time. Ultimately, 3R2N will identify a range of baseline

practices with clearly defined social-political strategies,

designed to enable communities to be involved in determining

the future of their rivers and waterfronts. Knauer and others

(2000) provided a summary of findings that includes fecalindicator bacteria sampling during the summer of 2001 from

sites on the Monongahela River from river mile 11.5 to 35.0

and on selected tributary streams to the Monongahela River.

Related Studies

Similar studies of fecal-indicator bacteria have been

initiated by the USGS in other regions of the country. Myers

and others (1998) evaluated the effects of stormwater, CSOs,

and wastewater-treatment discharges on the middle main stem

of the Cuyahoga River between Akron and Cleveland, Ohio.

Their results suggest that fecal-indicator bacteria frequently

exceeded Ohio’s WQS for recreation during rainfall and runoff

periods. Decay, transport, dilution, and dispersion of fecal

bacteria were evaluated in the Cuyahoga River to estimate

spatial and temporal variations in concentration. Decay rates

ranged from 0.0018 hr-1 to 0.0372 hr-1 for FC and from

0.0022 hr-1 to 0.0407 hr-1 for E. coli. Additionally, decay rates

reported in June and August 1992 were significantly higher

than those measured in April and October 1992. The

importance of streambed sediments as a source of bacteria

loading was assessed by collecting and enumerating fecalindicator bacteria at two locations in the Cuyahoga River.

Concentrations of fecal-indicator bacteria in the sediments

were from 1.2 to 58 times more concentrated per unit weight

than in the overlying water column.

Effects of wastewater and CSOs on E. coli concentrations were evaluated in the Blue River Basin, Kansas City,

Mo., and Kansas from July 1998 to October 2000 during base

flow (Wilkison and others, 2002). The median concentrations

of E. coli of 800 col/100 mL on the Blue River and

490 col/100 mL on Brush Creek exceeded the USEPA WQS.

Genetic fingerprint patterns of E. coli from selected stream

samples were compared to a data base of known source

patterns to determine possible sources of bacteria. Presumptive

sources of E. coli were almost equally divided among dogs

(28.3 percent), geese (22.1 percent), humans (23.4 percent),

and unknown sources (26.2 percent).

The USGS, in cooperation with the National Park

Service, began a 2-year study in 1999 to evaluate microbial

contamination in streams in and near the Chattahoochee River

National Recreation Area, Ga. Synoptic surveys indicated the

lowest FC concentrations in Chattahoochee River and

tributaries during low-flow conditions; in contrast, the highest

FC concentrations occurred during stormflow conditions

(Gregory and Frick, 2001). During diurnal sampling, indicatorbacteria concentrations were lowest during late afternoon,

following the period of most intense sunlight, and highest

during the night. Concentrations of FC, E. coli, and enterococci

were approximately 4, 6, and 8 times higher, respectively,

during the night than when sunlight intensity was highest.

Daily fluctuations in sunlight intensity may influence indicatorbacteria concentrations during low-flow conditions and in

shallow water.

Sources of Bacteria

Some potential sources of pathogens to receiving waters

such as the Three Rivers are listed below. They can be

categorized as point sources and nonpoint sources.

• combined sewer overflows (CSOs)

• sanitary sewer overflows (SSOs)

• overflows from wastewater treatment plants (WWTP)

• illicit sewage connections

• base flow and direct runoff from urban, agricultural,

and forested basins

• wildlife and livestock

• landfills

• septic systems

• pet waste

• waterfowl

• sanitary sewer leaks

Point Sources

Point-source discharges typically are associated with

end-of-pipe releases. Of these, raw sewage poses the greatest

potential source of human pathogens. Novotny and others

(1989, p. 2-6) reported concentrations of total coliform in

sewage ranged from 107 to 109 MPN (most probable number)

/100 mL. Proportionally high concentrations of pathogenic

organisms, including bacteria, viruses, protozoans, and other

parasites, are associated with raw sewage (U.S. Environmental

Protection Agency, 2001). The most common pathways for

introducing sewage into a receiving water include wet-weather

overflows from CSOs, SSOs, illicit sewage connections, and

WWTP effluent.

Combined sewers are water-collection systems designed

to convey stormwater and wastewater from domestic,

commercial, and industrial sources in a single pipe to a WWTP.

During wet weather, the distribution system or WWTP can be

hydraulically overloaded, resulting in the direct discharge of

untreated stormwater and wastewater to a receiving water. In

contrast, sanitary sewers are designed to carry only wastewater.

Illicit piping of storm drains, parking areas, and roof and

foundation laterals (inflow) can trigger overflows to receiving

waters, streets, or basements. Dry-weather discharges also may

occur in CSOs and SSOs, when inflow and excess ground

water or surface water are introduced by infiltration through

cracks, joints, and breaks in the piping network. The discharge

volume and concentration are dependent on the duration and
6 Fecal-Indicator Bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-Sept. 2001

antecedent conditions prior to a precipitation event. Typical

concentrations of total coliform bacteria in CSOs range from

105

 to 107 MPN/100 mL (Novotny and others, 1989, p. 2-6).

WWTPs typically reduce total coliform counts of raw

wastewater by approximately three orders of magnitude to 104

to 106 MPN/100 mL (U.S. Environmental Protection Agency,

2001); however, periodic overflows of effluent during high

flows could contribute higher concentrations of bacteria to

rivers and tributaries. Wastes from slaughterhouses, dairy

farms, and meat and poultry processing plants also could

contribute pathogenic loads to waterbodies.

Nonpoint Sources

Nonpoint sources of fecal contamination are diffuse. In

rural areas, the principal source of fecal matter is runoff from

confined animal operations (U.S. Environmental Protection

Agency, 2001); however, leachate in runoff from failing or

illicitly connected septic tanks and leachate from livestock,

pastures, rangelands, uncontrolled manure storage areas, and

wildlife also contribute significantly to bacteria in stream base

flow and stormflow. Beaver, deer, and waterfowl also

contribute pathogens to receiving waters.

Because urban basins contain impervious areas

engineered with drainage controls, stormwater runoff can

transport fecal matter associated with litter, domestic pets, and

wildlife. Coliform concentrations in urban stormwater are

consistent with those reported in WWTP effluent (U.S.

Environmental Protection Agency, 2001). Young and

Thackston (1999) determined that fecal-bacterial loading in

urban streams was a function of the density of housing,

population, development, impervious cover, and domestic

animal population.

Resuspension of bacteria-laden sediment is of particular

concern in large rivers systems such as the Three Rivers. The

pools created by lock and dam systems act as settling basins.

Depending on grain size and organic content, sediment within

a receiving water may serve as a reservoir for bacteria. Weiskel

and others (1996) reported an increase in FC density in

Buttermilk Bay, Mass., where the most prolific increases were

associated with sites in which the sediment consisted of finegrained, high-organic carbon muds. This suggests an affinity

for bacteria to adsorb onto the surfaces of fine-grained

sediments prior to being mobilized.

Bacteria-laden sediment could be resuspended in the

water column in a variety of ways including high flows

triggered by reservoir releases, direct runoff attributed to

precipitation, recreational and commercial boat traffic, lock

and dam operations, and scour related to an increase of

instream flow and velocity. Yagow and Shanholtz (1998)

reported that increasing bacteria concentrations in the water

column coincided with decreasing concentrations in stream

sediments. The sediments were then deposited downstream,

where bacteria concentrations in the sediment increased and

concentrations in the water column returned to background

levels. Depending on the degree of hydraulic connection

between ground water and surface water, base flow may

transport fecal loads to surface-water bodies.

Fate and Transport

A variety of factors influence the fate and transport of

pathogens and ultimately their concentration within a receiving

water. Physical, chemical, and biologic conditions that include

sunlight, temperature, moisture conditions, salinity, bottom

sediments, and related hydraulics of the receiving water affect

pathogen die-off rates. Additionally, contaminant pathways

influence attenuation rates by exposing pathogens to conditions

that may not be favorable for survival.

The factors that are most significant in determining

pathogen die-off rates are sunlight (ultraviolet and nearultraviolet radiation), temperature, and moisture. Increased

rates of ultraviolet radiation increase die-off rates in bacteria

and viruses (U.S. Environmental Protection Agency, 2001).

Suspended sediment will scatter sunlight. As a result, the effect

of sunlight is limited by its penetration depth within the water

column. For example, the die-off rate for bacteria near the

water surface will be greater than for bacteria near the channel

bottom.

Survival of pathogen and indicator bacteria is dependent

on ambient temperature (U.S. Environmental Protection

Agency, 2001). The relation is an inverse one, suggesting that

increasing temperatures result in decreasing survival rates.

Gerba and Britton (1984) reported that die-off rates for

coliform bacteria in soil doubled for each 10°C increase in

temperature.

Bacteria survival times increase with moisture content

and retention (Reddy and others, 1981). Therefore, soil with a

high clay content will have a greater soil-moisture retention

capacity and greater propensity for bacteria to proliferate.

Bottom sediments provide a safe haven for bacteria

populations against radiation and temperature variations.

Burton and others (1987) reported the number of indicator and

pathogenic bacteria in bottom sediments is greater than that in

the overlying water column. Sherer and others (1992) report

the survival times for FC in bottom sediments is greater than

those for the water column, suggesting that bacteria can

survive in bottom sediments for extended periods of time

compared to that of the water column. This reservoir allows

bacteria to survive for up to several months, increasing the

potential for recreational contact from resuspension. Survival

rates for FC and fecal streptococci were significantly longer

(11 to 30 days and 9 to 17 days, respectively, when incubated)

in sediment-laden water than in water without sediment (U.S.

Environmental Protection Agency, 2001).
Study Design 7

Study Design

The study was designed to estimate bacteria

concentrations in the large rivers entering and exiting

Allegheny County. Additionally, it was important to establish

the bacteria contributions of the Allegheny and Monongahela

Rivers prior to their discharging to the Ohio River. Five

sampling sites on the Three Rivers in Allegheny County near

Pittsburgh, Pa., were chosen (fig. 1). Two sampling sites were

selected along the Allegheny and Monongahela Rivers,

respectively, and one site was selected along the Ohio River

(table 1).

Site Selection

Sites that did not have previous streamflow or waterquality data include the Allegheny River at Oakmont

(Oakmont), the Allegheny River at 9th Street Bridge (9th St.

Bridge), and the Monongahela River at Pittsburgh (Smithfield

St. Bridge). The location of the Allegheny River at Oakmont

was selected, because it was upstream of a high density of

CSOs on the riverbanks in the City of Pittsburgh, and because

the Oakmont bridge permitted safe access of personnel and the

cranes used to sample the river from the bridge. The locations

of the Allegheny River at 9th Street Bridge and Monongahela

River at Pittsburgh were selected to estimate the contributions

of fecal-indicator bacteria of these rivers to the Ohio River. The

Monongahela River at Braddock (Braddock) and the Ohio

River at Sewickley (Sewickley) are active USGS streamflowmeasurement stations where water-quality samples are

collected (Siwicki, 2002).

Sampling Protocol

To measure fecal-indicator bacteria in large river

systems, two factors were considered during development of

the sampling protocol:

• Wet-, dry-, and mixed-weather conditions during lowbase flow and high-base flow periods

• Mixing of point- and nonpoint-discharge sources with

a receiving water

The study adopted the definitions of wet- and dryweather conditions established by ORSANCO. Namely, a wetweather event is characterized by at least a 48-hour dry

antecedent period and at least 0.3 in. of precipitation in a

6-hour period; a dry-weather event is dominated by at least a

72-hour dry antecedent period. Additionally, only those storms

that encompassed large parts of Allegheny County were

selected. In some cases, samples were collected under mixedweather conditions that did not meet the above constraints.

The degree of mixing played a significant role in

establishing sample locations. Under poorly mixed conditions,

point discharges such as a tributary containing elevated

bacteria concentrations may be strongly deflected by the

receiving water and hug the side of the receiving water

channel. Alternatively, under well-mixed conditions, one may

expect peak concentrations to coincide with that part of a

channel where the maximum velocity occurs.

Equal discharge-increment (EDI) sampling and grab

sampling were utilized at each section. For each sampling

event, three samples were collected at each site, one

characteristic of the channel cross-section (EDI sample) and

two grab samples near the left bank and right bank at each

section (about 20 ft from shore at a depth of 18 in.). EDI

samples provide an advantage over conventional grab samples

in that they represent an integrated discharge-weighted sample.

As a result, the concentration reported can be used in conjunction with the flow rate measured at the section to determine the

load at the time of sampling. Details describing the EDI

method are described by USGS (1997 to present) at http://

water.usgs.gov/usgs/publishing/Memos/memo2002_15.html.

The general process associated with the sampling method is

shown in figure 2.

Table 1. Description of sampling sites on the Allegheny, Monongahela, and Ohio Rivers near Pittsburgh, Pennsylvania.

Site name

U.S. Geological

Survey site

identification

number

Sample

obtained

from

River mile

(miles)

Distance upstream

to the Allegheny

County border

(miles)

Drainage area

(square miles)

Allegheny River at Oakmont (Oakmont) 03049652 bridge 1 12.7 28 11,577

Allegheny River at 9th Street Bridge (9th St. Bridge) 03049832 boat 1.7 16 11,710

Monongahela River at Braddock (Braddock) 03085000 boat 2 11.2 25 7,337

Monongahela River at Pittsburgh (Smithfield St. Bridge) 03085150 boat 2.8 16 7,367

Ohio River at Sewickley (Sewickley) 03086000 bridge 3 13.3 3.6 19,500

1 River miles are measured from the site to the mouth of the Allegheny River.

2 River miles are measured from the site to the mouth of the Monongahela River.

3 River miles are measured from the site to the confluence of the Allegheny and Monongahela Rivers.
8 Fecal-Indicator Bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-Sept. 2001

Figure 2. Cumulative percentage of discharge and stream cross section in an example

of an equal discharge incremental (EDI) sample (modified from U.S. Geological Survey,

1997 to present, figure 4-3).
Study Design 9

Sampling Protocol Evaluation

The sampling protocols that consisted of an EDI sample

and separate left-bank and right-bank samples were selected on

the basis of a variety of logistical concerns, cost efficiency, and

informational needs. The ACHD and USGS agreed that point

samples provide a discrete measure of concentrations of fecalindicator bacteria, which are a function of depth and distance

from the water’s edge; however, because of cost constraints

and the objective to estimate daily loads of fecal-indicator

bacteria, composite samples rather than point samples were

proposed as the procedure to routinely estimate the extent of

bacterial contamination at a given sampling site.

A demonstration project was conducted at the request of

the USEPA to compare EDI samples against samples that were

not composited. The selected site was on the Ohio River at

Sewickley near Pittsburgh, Pa. Two depth-integrated samples

were collected at each of four stations along the cross section.

Samples were combined (one from each of the four stations) to

make up a composite sample using EDI techniques. The

remaining samples from each station were processed and

analyzed independently (discrete samples) (table 2).

Two primary conclusions can be drawn from the data

presented: 1) bacterial concentrations vary across the width of

the Ohio River at Sewickley and 2) EDI samples do not always

approximate the mean of the quarter-point samples. In some

instances, the comparability of the mean and composite sample

was good with percentage differences as low as 4 percent.

However, the percentage differences in some samples was as

great as 167 percent. The need to use compositing techniques

was confirmed, and the EDI technique was retained as the

protocol for this project.

Streamflow Measurements

In an effort to establish appropriate EDI sample

locations, real-time streamflow measurements were made at

each section at selected times during the sampling program,

where a period of record was absent (Allegheny River at

Oakmont, Allegheny River at 9th Street Bridge, and

Monongahela River at Pittsburgh) or where a boat site was

stationed (Monongahela River at Braddock). Real-time

measurements were made using an acoustic Doppler current

profiler (ADCP) mounted to a boat. The ADCP unit transmits

sound bursts at a fixed ultrasonic frequency of 600 kHz into the

water column. Suspended particles in the water scatter the

acoustic bursts back to the unit. As echoes return from deeper

depths in the water column, the unit assigns various water

depths to each echo record and measures the Doppler shift in

the acoustic bursts. The resulting output provides a measure of

the water velocity, depth, and discharge within open channels.

When configured, the unit is capable of measuring the channel

depth to within ± 10 cm or 0.33 ft and channel velocity to

within 3 percent. The largest source of error is its inability to

obtain velocity data near the water surface, channel bottom,

and sides. An ADCP transect of the Monongahela River at

Braddock is presented in figure 3 and was initiated at 0900 on

August 28, 2001. The profile illustrates the velocity

distribution captured by a tow barge passing upstream and the

resultant propeller wash created by the barge. Streamflow was

computed to be 5,670 ft3/s.

At sections where streamflow is measured continuously

(Ohio River at Sewickley and Allegheny River at Oakmont -

estimates determined from the Allegheny River at Natrona,

11 mi upstream of Oakmont), velocity-distribution data were

reviewed to establish appropriate EDI sample locations.

Ideally, time-of-travel estimates and hydrographs could

be developed and reviewed for each site to ensure the sample

time coincided with a point on the rising limb, at peak flow,

and on the falling limb of the hydrograph. However, regulation

of river flows by flood-control dams within the Three Rivers

region and water withdrawals for power generation and water

supply precluded this effort. These influences are illustrated in

figure 4, which shows the streamflow recorded at the

Sewickley streamflow-measurement station on the Ohio River

during a period of no precipitation.

Table 2. Comparison of bacteria concentrations in discrete and

composite samples collected from the Ohio River at Sewickley,

Pennsylvania.

[Bacteria concentrations in colony forming units per 100 milliliters]

Date Station, in feet from river bank

July 24, 2001 –

Bridge Team 250 480 740 1,000 Mean

Composite

sample

concentration

Enterococci 10 3 15 5 8 3

Escherichia coli 3 5 90 40 34 15

Fecal coliform 20 15 120 15 43 40

August 28,

2001 –

Bridge Team

250 480 750 1,010 Mean

Composite

sample

concentration

Enterococci 5 5 15 20 11 10

Escherichia coli 140 260 490 110 250 240

Fecal coliform 220 170 100 130 155 760

September 26,

2001 –

Boat Team

243 453 768 1010 Mean

Composite

sample

concentration

Enterococci 15 10 50 10 21 20

Escherichia coli 600 440 2,100 2,100 1,310 2,000

Fecal coliform 2,600 420 4,700 3,100 2,705 3,200
10 Fecal-Indicator Bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-Sept. 2001

Figure 3. River cross-section and stream-velocity profile generated from acoustic Doppler current profiler,

Monongahela River at Braddock, Pennsylvania, (03085000), August 28, 2001.

Figure 4. Hydrograph from the streamflow-gaging station on the Ohio River

at Sewickley, near Pittsburgh, Pa., on August 4-7, 2001, prior to the August 8

wet-weather event.

2400 1200 2400 1200 2400 1200 2400 1200 2400

4 5 6 7

August 2001

4,000

14,000

5,000

6,000

7,000

8,000

9,000

10,000

11,000

12,000

13,000

STREAMFLOW, IN CUBIC FEET PER SECOND

Storm hydrograph recession after rain

in West Virginia on July 28 and 29.

Variations in streamflow are related to

hydropower generation, pool and reservoir

regulation on the Allegheny, Monongahela,

and Ohio Rivers.
Occurrence and Distribution of Fecal-Indicator Bacteria 11

Water-Quality Sampling Methods

Water samples were collected and analyzed for the

following constituents: (1) FC bacteria, (2) E. coli bacteria,

(3) enterococci bacteria, (4) turbidity, (5) specific conductance

(SC), (6) temperature, (7) dissolved oxygen (DO), and (8) pH.

Field and quality-assurance methods were consistent

with those referenced in the National Field Manual for the

Collection of Water-Quality Data (Wilde and others, 1999) and

in accordance with the approved Quality Assurance Project

Plan (QAPP) and amendments issued to the USEPA prior to

project initiation. The analyses of the fecal-indicator bacteria

were performed using membrane filtration methods by

laboratory staff of the ACHD. The procedures used for the

analysis of FC bacteria are from Standard Methods for the

Examination of Water and Wastewater by the American Public

Health Association and others (1998, p. 9-63 to 9-65). The

analysis of enterococci bacteria was done by the American

Public Health Association and others (1998, p. 9-76 to 9-78).

The methods used for E. coli bacteria (Method 1103.1 using

mTEC Agar) were those of the USEPA (2000, p. 24-35).

Aseptic techniques were maintained for collection of

water samples for analysis of fecal-indicator bacteria, and

sterile containers and equipment were used during the

sampling effort. Water samples for fecal-indicator bacteria

were packed in ice and transported within the 6-hour holding

time to the ACHD Laboratory for analysis in accordance with

the approved QAPP.

Quality Assurance

Field replicate samples were collected at a rate of

5 percent of the total number of samples collected. Laboratory

replicate analyses were performed by the ACHD Laboratory.

Bacteria sample bottles were tested to check for the efficiency

of sterilization.

Two types of bottles were sterilized and routinely used

in the analysis of fecal-indicator bacteria. During EDI

sampling, 3-L sterilized bottles with sterilized caps and

sterilized nozzles were fitted in the basket samplers used by the

bridge team and the boat team. After shaking the 3-L bottles to

mix their contents, river samples were poured from the 3-L

bottles to a 250-mL polyethylene bottle that was previously

sterilized. On a monthly basis, efficiency of sterilization was

tested separately for the 3-L bottles and the 250-mL bottles.

A certified sterile buffered water solution from the USGS

Ocala Laboratory (Ocala, Fla.) was added to the 3-L bottle in

the field and sent to the ACHD laboratory for analysis of FC,

E. coli, and enterococci. No fecal bacteria were detected in the

repeated monthly trials of this procedure; this indicates that the

sterilization procedures for the 3-L bottles were effective.

A similar procedure was done by pouring certified sterile

buffered water into the sterilized 250-mL bottle in the field and

sending the sample to the ACHD laboratory for the analysis of

fecal-indicator bacteria. No fecal bacteria were detected in the

repeated monthly trials of this procedure; this indicates that the

sterilization procedures in use for the 250-mL bottles were

effective.

Field-replicate samples were collected at the sites on the

Allegheny River at Oakmont, Allegheny River at 9th Street

Bridge, Monongahela River at Braddock, and Monongahela

River at Pittsburgh (table 3). These field replicate samples were

collected by using the water collected from an EDI sample and

successively filling two 250-mL sterilized bottles after

vigorously shaking the river sample collected in the 3-L

sterilized EDI bottle. Even with vigorous shaking of the 3-L

river sample, complete homogeneous mixing of the sample

may be nearly impossible because of instantaneous settling of

sediment/bacteria mixtures and clumping of bacteria to

suspended organic substances. These field replicates test both

the efficiency of mixing in the 3-L EDI bottle and laboratory

replication efficiency. When concentrations in sample 1 and

sample 2 are different (table 3), the differences may be caused

by incomplete field mixing in the 3-L sample and (or)

laboratory replication efficiency.

The results of the field replicate samples indicate good

agreement between samples when concentrations of fecalindicator bacteria are at the detection level (<5 col/100 mL).

However, when concentrations of fecal-indicator bacteria are

higher than detection levels, agreement between samples

declines markedly (table 3). The largest discrepancy between

samples was on August 29, 2001, when sample 1 was

2,300 col/100 mL and sample 2 was 140 col/100 mL.

Additional data and side-by-side comparisons are needed to

evaluate the significance of this result and identify a basis for

the discrepancy between replicate samples when fecalindicator bacteria concentrations are elevated.

Occurrence and Distribution of FecalIndicator Bacteria

Bacteria Concentrations and Distributions

Concentrations of E. coli, enterococci, and FC during

dry-weather sampling events were greater than the WQS in 11,

28, and 28 percent of the samples, respectively; during mixedweather events, concentrations of fecal-indicator bacteria were

greater than the WQS in 28, 37, and 43 percent of the samples,

respectively; and during wet-weather events, concentrations of

fecal-indicator bacteria were greater than the WQS in 56, 71,

and 81 percent of the samples, respectively (table 4).

A summary of streamflow and water-quality data is presented

in Appendix 1.

During the sample-collection period from July 12 to

September 28, fecal-indicator bacteria samples were collected

during dry-weather conditions on 4 days (July 24, August 7,

September 4 and 18). The median concentrations for E. coli,

enterococci, and FC were 30, 5, and 70 col/100 mL, respec-
Table 3. Concentrations of field replicate samples for fecal-indicator bacteria, Allegheny and Monongahela Rivers, July-September 2001. [Fecal-indicator bacteria concentrations in colony-forming units per 100 milliliters; <, less than] Fecal- indicator bacteria Allegheny River at Oakmont Allegheny River at 9th Street Bridge Monongahela R

at Braddock 

7/31/01 08/09/01 8/21/01 09/26/01 09/27/01 9/25/01 

Sample 1 Sample 2 Sample 1 Sample 2 Sample 1 Sample 2 Sample 1 Sample 2 Sample 1 Sample 2 Sample 1 Sam

Escherichia coli <5 <5 <5 <5 <5 <5 220 150 35 45 1,600 1,4Enterococci <5 <5 <5 <5 <5 <5 10 <5 5 <5 220 3Fecal coliform <5 <5 5 <5 <5 5 580 540 90 120 15,000 19,0
Occurrence and Distribution of Fecal-Indicator Bacteria 13

tively. These median concentrations were below the WQS.

During mixed-weather events, the median concentra-tions also

were below the WQS; median concentrations of E. coli, enterococci, and FC were 50, 2.5, and 80, respectively. Median concentrations exceeded the WQS only during wet weather. The

median concentration of E. coli (410 col/100 mL) for wetweather samples exceeded the WQS of 126 col/100 mL. The

median concentration of FC (695 col/100 mL) for wet-weather

samples exceeded the WQS of 200 col/100 mL.

Summary statistics for streamflow, temperature, and

concentrations of fecal-indicator bacteria for the five sampling

sites within the Three Rivers for July through September are

provided in table 5. The lowest median concentrations for

E. coli, enterococci, and FC were measured at the Allegheny

River at Oakmont. Median concentrations for fecal-indicator

bacteria for the four other sites were similar to each other.

Median concentrations at these sites were roughly 5 to

10 times greater than that at the Allegheny River at Oakmont.

Table 4. Summary of concentrations of fecal-indicator bacteria

that are above or below water-quality criteria for dry-, mixed-, and

wet-weather events, July-September 2001, Allegheny County,

Pennsylvania.

Number of

samples

Percentage of

samples with

concentrationsabove

the water-quality

standard

Dry-weather samples1

Enterococci 57 11

Escherichia coli 57 28

Fecal coliform 57 28

Mixed-weather samples2

Enterococci 75 28

Escherichia coli 75 37

Fecal coliform 75 43

Wet-weather samples3

Enterococci 129 56

Escherichia coli 129 71

Fecal coliform 129 81

1 Includes left bank, right bank, and equal discharge-incremental sample

for July 24, August 7, and September 4 and 18.

2 Includes left bank, right bank, and equal discharge-incremental sample

for July 12, 18, and 31, and August 14 and 21.

3 Includes left bank, right bank, and equal discharge-incremental sample

for August 8-10, August 28-30, and September 25-28.

Table 5. Summary statistics for streamflow, temperature, and

concentrations of fecal-indicator bacteria for the five sampling

sites within the Three Rivers region, Pa., July-September 2001.

[min, minimum; max, maximum; <, less than]

Streamflow,

in cubic

feet per

second

Temperature,

in degrees

Celsius

Escherichia coli,

in colonies

per 100 milliliters

Enterococci, in colonies per 100

milliliters

Fecal

coliform,

in colonies

per 100 milliliters

Allegheny River at Oakmont

Min: 2,810 20 <5 <5 <5

Median: 4,040 29 28 5 50

Max: 5,650 35 820 690 960

Allegheny River at 9th Street Bridge

Min: 3,140 19.5 3 <5 <5

Median: 4,220 27 140 15 280

Max: 5,910 30 7,900 575 21,000

Monongahela River at Braddock

Min: 2,350 19.5 <5 <5 <5

Median: 5,400 26.5 280 30 520

Max: 21,800 29.0 12,000 630 23,000

Monongahela River at Pittsburgh

Min: 2,700 21 5 <5 10

Median: 5,270 26 260 25 620

Max: 19,900 30 39,000 1,060 50,000

Ohio River at Sewickley

Min: 6,480 17.5 <5 <5 8

Median: 11,400 27 220 20 245

Max: 26,300 32 3,100 705 31,000
14 Fecal-Indicator Bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-Sept. 2001

Wet-weather concentrations exceeded those reported during dry-weather events for all sites, except the Allegheny River

at Oakmont (figs. 5, 6, and 7). This may be a function of dilution during wet-weather events or the lack of upgradient source

streams. Additionally, concentrations of E. coli and FC frequently exceeded the WQS reported during wet-weather events.

For dry-weather conditions, only three sample events (July 24,

September 4, 18) met the 72-hour antecedent condition of no

rainfall. As a result, comparing data between sites should be

done with caution. Additional data would be needed to develop

more definitive relations between sites.

Weather Effects

Establishing a trend in concentrations of fecal-indicator

bacteria as a function of time after a wet-weather event carries

a measure of uncertainty because of a variety of factors including the spatial variability of sources contributing fecal material,

dry-weather discharges, resuspension of bottom sediments, and

flow augmentation from the U.S. Army Corps of Engineer

(USACE) reservoirs. However, FC concentrations appear to

decrease with time compared to the other fecal-indicator bacteria. This decrease may be attributed to the greater rate of die-off,

which is consistent with FC bacteria. A summary of wetweather data from composite samples collected at each sample

location is presented in table 6.

Figure 5. Fecal-indicator bacteria colonies in composite samples collected on the Allegheny, Monongahela, and Ohio

Rivers near Pittsburgh, Pa., during dry weather, 2001.
Occurrence and Distribution of Fecal-Indicator Bacteria 15

Figure 6. Fecal-indicator bacteria colonies in composite samples collected on the Allegheny, Monongahela, and Ohio

Rivers near Pittsburgh, Pa., during mixed weather, 2001.
16 Fecal-Indicator Bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-Sept. 2001

Figure 7. Fecal-indicator bacteria colonies in composite samples collected on the Allegheny, Monongahela, and Ohio

Rivers near Pittsburgh, Pa., during wet weather, 2001.
Occurrence and Distribution of Fecal-Indicator Bacteria 17

Routine sampling for fecal-indicator bacteria began on

July 12 and extended to September 28. In general, dry-weather

or mixed-weather samples were collected weekly at each section. Three wet-weather events also were sampled. On August

8, August 28, and September 24, approximately 1.39, 1.87, and

0.85 in. of precipitation, respectively, were recorded at the

Pittsburgh International Airport rain gage operated by the

National Weather Service (NWS). At a network of 21 precipitation gages in Allegheny County, median precipitation quantities for August 8, August 28, and September 24 were 0.39, 1.11,

and 0.77 in., respectively. In addition, samples were collected

on selected days after precipitation ended in an effort to establish the period of time needed for bacteria concentrations to

decline to below the WQS.

Concentrations of fecal-indicator bacteria for the five sites

on the Three Rivers sampled during dry weather on August 7

are presented in figure 8. No precipitation was measured on

August 4, 5, and 6, and during the day of sampling on August

7; therefore, the event complied with the definition of dry

weather established by ORSANCO. The concentrations of

enterococci, E. coli, and FC were below the WQS on August 7

for bank and composite samples at the following sites:

Allegheny River at Oakmont, Allegheny River at 9th St.

Bridge, and Ohio River at Sewickley. Concentrations of FC and

E. coli at the Monongahela River at Braddock were slightly

above the WQS, and the enterococci concentrations were below

the WQS. The cause(s) of the elevated concentrations of E. coli

and FC during dry weather are unknown, but possible sources

may include sewage discharging from tributary streams

upstream of the site, waterfowl, malfunctioning sewage-treatment plants or overflows, leaking sewer lines, marinas, malfunctioning onlot sewage systems, and agricultural runoff.

On August 8, 2001, heavy rains fell on part of Allegheny

County from approximately 2 a.m. to 6 a.m. The long-term rain

gage at Pittsburgh International Airport recorded 1.39 in.,

a record for August 8. Nine rain gages in the NWS network in

Allegheny County recorded from 0.04 to 1.55 in.; the median

precipitation for these gages was 0.44 in. The rain was concentrated mostly in Allegheny County; the median rainfall quanti- ties from the NWS county networks in the adjacent counties of

Armstrong, Butler, Washington, and Westmoreland were all

zero. This rainfall event for Allegheny County met the criteria

for wet weather as defined by ORSANCO (a 48-hour dry antecedent period and at least 0.3 in. of precipitation in a 6-hour

period).

Concentrations of fecal-indicator bacteria were above the

WQS for composite and bank samples collected on August 8 at

the following sites: Allegheny River at 9th St. Bridge, Monongahela River at Braddock, Monongahela River at Pittsburgh,

and Ohio River at Sewickley (fig. 9). At the site at Allegheny

Table 6. Concentrations of fecal-indicator bacteria in composite samples collected during wet-weather events, Allegheny,

Monongahela, and Ohio Rivers near Pittsburgh, Pennsylvania, August-September 2001.

[ns, no sample]

Site name

Sampling date

August August September

8 9 10 28 29 30 25 26 27 28

Escherichia coli, in colonies per 100 milliliters

Ohio River at Sewickley 1,300 400 420 240 2,300 2,300 ns 2,000 ns 140

Monongahela River at Braddock 6,000 35 510 520 2,000 50 1,600 90 570 ns

Allegheny River at Oakmont 2.5 2.5 2.5 25 2.5 15 15 ns 15 ns

Allegheny River at 9th Street Bridge 2,700 440 6,400 420 2,200 35 690 220 35 ns

Monongahela River at Pittsburgh 1,800 180 2,000 280 2,300 260 960 870 500 ns

Enterococci, in colonies per 100 milliliters

Ohio River at Sewickley 350 115 70 10 310 180 ns 20 ns 15

Monongahela River at Braddock 125 20 15 130 250 150 220 15 135 ns

Allegheny River at Oakmont 2.5 2.5 2.5 25 2.5 25 2.5 ns 2.5 ns

Allegheny River at 9th Street Bridge 230 20 225 20 265 100 5.0 2.5 5.0 ns

Monongahela River at Pittsburgh 130 15 195 20 90 685 2.5 5.0 10 ns

Fecal coliform, in colonies per 100 milliliters

Ohio River at Sewickley 650 580 250 760 2,200 770 ns 3,200 ns 230

Monongahela River at Braddock 8,000 90 840 1,500 1,700 740 15,000 250 320 ns

Allegheny River at Oakmont 2.5 5.0 35 50 5 10 5 ns 15 ns

Allegheny River at 9th Street Bridge 4,400 560 14,000 750 3,300 540 880 580 90 ns

Monongahela River at Pittsburgh 3,500 3,400 2,800 650 2,600 3,900 810 880 230 ns
18 Fecal-Indicator Bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-Sept. 2001

Figure 8. Concentrations of fecal-indicator bacteria during dry weather on August 7, 2001, from five sites on the Allegheny,

Monongahela, and Ohio Rivers near Pittsburgh, Pennsylvania.
Occurrence and Distribution of Fecal-Indicator Bacteria 19

Figure 9. Concentrations of fecal-indicator bacteria after wet weather on August 8, 2001, from five sites on the Allegheny,

Monongahela, and Ohio Rivers near Pittsburgh, Pennsylvania.
20 Fecal-Indicator Bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-Sept. 2001

River at 9th St. Bridge and the Ohio River at Sewickley site, the

wet-weather effects on the bacteria concentrations resulted in

all samples exceeding the WQS on August 8; concentrations

were below the WQS the previous day (fig. 8). The Allegheny

River at Oakmont was on the periphery of the storm on August

8, resulting in reduced runoff rates compared to stations in areas

receiving larger rainfall amounts. The pattern of composite

samples of the three indicator bacteria below the WQS for several days after wet-weather events also was observed during the

other two wet-weather events on August 28-30 and September

25-27. A hypothesis that could be tested in future wet-weather

sampling would be to examine if the daily discharges suspected

of containing few bacteria from many USACE reservoirs

upstream of the Allegheny River at Oakmont act to dilute the

loads of bacteria discharging to the Allegheny River upstream

of Oakmont during wet weather. Bacteria source streams, entering the Allegheny River between Oakmont and 9th St. Bridge

during the wet-weather event of August 8, resulted in all nine

samples for all three indicator bacteria being above the WQS

for the August 8 samples collected from the Allegheny River at

9th St. Bridge. This supports the findings that a source(s) of

bacterial contamination exists between the Oakmont and 9th St.

Bridge sites.

The bacteria concentrations reported in some of the bank

samples collected at each site were greater than in the composite sample. This is attributed in part to incomplete mixing of

source streams adjacent to the river banks. Depending on the

difference in the momentum between the source and the receiving water, the discharges may be strongly deflected and have a

tendency to hug the side of the receiving water channel. This is

particularly true within the near-field mixing region, where the

jet characteristics of the discharge (momentum, buoyancy, and

outfall geometry) dominate. As the plume travels downstream,

these characteristics become less important, and the characteristics of the receiving water (momentum, velocity distribution,

channel geometry, buoyant spreading, and diffusion) dominate

the mixing process. The point at which mixing becomes more

uniform is based on the distribution of additional point discharges downstream and the hydrodynamics of the receiving

water. In the event conditions are well-mixed, peak concentrations would be expected to coincide with that part of a channel

where the maximum velocity occurs.

Monongahela River Subbasins

During the sampling period, the greatest median concentrations of E. coli (280 col/100 mL, 260 col/100 mL) and

enterococci (30 col/100 mL, 25 col/100 mL) bacteria were

reported at Monongahela River at Braddock and Monongahela

River at Pittsburgh, respectively (table 4). Maximum concentrations of E. coli, enterococci, and FC were 12,000; 630; and

23,000 col/100 mL, respectively, for the Monongahela River at

Braddock. The elevated concentrations along the Monongahela

River compared to the other rivers may be attributed to a number of variables, including the predominant land use within the

subbasins, the distribution of CSOs/SSOs, high streamflows,

and resuspension of sediments.

The land use within the study area is shown in figure 10.

The percent urban land cover for the Monongahela River subbasins is greater than or equal to that reported for the Allegheny

and Ohio Rivers. The Monongahela River subbasins include the

area drained by the Monongahela River and its tributaries

within the border of Allegheny County. As previously indicated, areas dominated by urban and suburban basins may generate fecal-indicator bacteria. Stormwater runoff, which can

contain coliform concentrations consistent with those reported

in WWTP effluent (U.S. Environmental Protection Agency,

2001), in impervious areas can quickly transport fecal matter

from litter, pets, and wildlife.

Additionally, the number of CSOs and SSOs per square

mile is greater for the Monongahela River subbasins than that

reported for the Allegheny River (fig. 11). The relative contributions of fecal material from these discharges could explain

the elevated bacteria concentrations reported at the Monongahela River sampling sites.

Resuspension of sediment within large river systems may

contribute fecal matter to the water column. Recreational and

commercial boat traffic or high streamflow within the Monongahela River subbasins may contribute to resuspended sediment

within the channel. This is supported in part by the velocity distribution shown in figure 3, which suggests that effects such as

barge propeller wash cause vertical flow components that

extend to the channel bottom 15 ft below the water surface. During a routine sampling event, the ADCP streamflow measurement was interrupted by intermittent barge traffic. Typically,

four transects are performed, and the discharge rate is then

established using the mean of the four measurements. After two

transects, the measurement was temporarily discontinued until

the traffic passed. However, during subsequent transects, it was

evident that velocity distribution was altered significantly by

the propeller wash associated with the barge. However, whether

the sediment contains fecal matter has not been confirmed.

To evaluate the significance of the concentrations of fecalindicator bacteria and turbidity reported in grab and composite

samples during dry-, mixed-, and wet-weather events, data sets

were evaluated using Wilcoxon rank sum tests. Tests were conducted using each of the fecal-indicator bacteria by site and by

weather event. For example, concentrations of FC reported in

the left-bank sample were compared to the right-bank and composite samples for the Ohio River at Sewickley site during dry,

mixed, and wet events.

The Wilcoxon rank sum test is a nonparametric test used

to evaluate independent data sets for one sample, two samples,

and paired samples. It tests the shift in location between the

populations (i.e. the measurements from one population are

either greater or less than those from the other population). The

Wilcoxon rank sum test offers the following two advantages

over other test statistics such as the independent t-test, including

(1) data sets are not forced to fit a normal distribution, and
Occurrence and Distribution of Fecal-Indicator Bacteria 21

Figure 10. Land cover of five subbasins within the Allegheny, Monongahela, and Ohio Rivers region, Allegheny County,

Pennsylvania.
22 Fecal-Indicator Bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-Sept. 2001

Figure 11. Distribution of combined sewer overflows (CSOs) and sanitary sewer overflows (SSOs) near Pittsburgh,

Pennsylvania.
Occurrence and Distribution of Fecal-Indicator Bacteria 23

(2) ranking can be incorporated into the analysis. The results of

the analysis are presented in table 7.

For the Monongahela River at Braddock, no statistically

significant relations were observed for the three fecal-indicator

bacteria for these three comparisons: 1) right-bank grab sample to composite sample, 2) left-bank grab sample to composite

sample, and 3) right-bank grab sample to left-bank grab sample

(table 7). For dry-weather samples for the Monongahela River

at Pittsburgh, two statistically significant relations were

observed for enterococci: 1) right-bank grab samples were different than composite samples and 2) left-bank samples were

different than composite samples. For the Monongahela River

at Braddock, four of nine turbidity comparisons were statistically significant (table 7). For the Monongahela River at Pittsburgh, three of nine turbidity comparisons were statistically significant.

Additional data sets are needed to adequately assess the

significance of the distribution of bacteria at a given station.

This is particularly true for wet-weather events; where days 1,

2, and 3 after a storm were evaluated collectively. For example,

with the inclusion of additional data; right bank, wet weatherday 1 samples for the Ohio River at Sewickley can be compared

to the composite, wet weather-day 1 sample for the same station. The existence of lack of significance may be influenced by

factors such as bacteria die-off rates and supplemental source

streams.

Allegheny River Subbasins

Flow augmentation associated with upstream reservoirs

operated and maintained by the USACE along the Allegheny

River may provide some degree of dilution for fecal loads discharged to the river. Depending on the time of year, these reservoirs can provide as much as 25 percent of the flow reported at

the streamflow-measurement station on the Allegheny River at

Natrona, 11.6 mi upstream of the Allegheny River at Oakmont.

Additionally, the number of CSOs and SSOs upstream of Oakmont on the border of Allegheny County are limited to about 12.

Therefore, the contribution of these point-source discharges

may be small compared to the number of source streams on the

Monongahela River. This is supported by the median concentrations of E. coli (28 col/100 mL) and enterococci

(5 col/100 mL) (table 5). Maximum concentrations of E. coli,

enterococci, and FC were 820, 690, and 960 col/100 mL,

respectively, for the Allegheny River at Oakmont.

Concentrations of fecal-indicator bacteria at the sampling

site on the Allegheny River at 9th St. Bridge are greater than

those reported at Oakmont. The median concentrations of

E. coli (140 col/100 mL) and enterococci (15 col/100 mL)

reported during the sampling period are shown in table 5. Maximum concentrations of E. coli, enterococci, and FC were

7,900; 575; and 21,000 col/100 mL, respectively (table 5). The

increase appears to be attributed to the high number of CSOs

and SSOs between 9th St. Bridge and Oakmont and the change

in land use close to the mouth of the Allegheny River.

For the Allegheny River at Oakmont (table 7), six statistically significant relations were observed for wet-weather samples for the three fecal-indicator bacteria. Comparison of the

concentrations in bank samples and composite samples (Appendix 1) indicates that the bank-sample concentrations generally

were larger than the composite samples. Only one statistically

significant relation for Oakmont was observed for dry weather.

For E. coli, left-bank grab samples were different from composite samples for dry-weather samples. A statistically significant

p-value of 0.04 indicated that left-bank grab samples were different from composite samples for enterococci concentrations

for mixed weather at Oakmont. No statistically significant relations were observed for turbidity for the Allegheny River at

Oakmont (table 7).

For the sampling site on the Allegheny River at 9th St.

Bridge, two significant relations were observed for enterococci

in mixed-weather samples: 1) right-bank samples were different from composite samples, and 2) right-bank samples were

different from left-bank samples. For this sampling site, five of

nine relations for turbidity were significant (table 7).

Ohio River Subbasins

Concentrations of fecal-indicator bacteria at the Ohio

River at Sewickley, in part, represent the combined flows of the

Allegheny and Monongahela Rivers and additional point and

nonpoint discharges downstream of the Ohio River confluence.

Median concentrations of E. coli (220 col/100 mL) and enterococci (20 col/100 mL) are similar to those reported at the

Allegheny River at 9th St. Bridge, the Monongahela River at

Braddock, and the Monongahela River at Pittsburgh. Maximum

concentrations of E. coli, enterococci, and FC were 3,100; 705;

and 31,000 col/100 mL, respectively (table 5).

One significant relation (p-value = 0.04) was observed for

E. coli during wet-weather events in left-bank compared to

composite samples. A statistically significant comparison

(p-value = 0.081) of right-bank compared to left-bank samples

during dry weather was observed for enterococci. Similar

observations were noted for turbidity; two statistically significant relations were observed: 1) dry-weather right-bank samples had different turbidity readings than dry-weather composite samples, and 2) mixed-weather right-bank samples had

different turbidity readings than composite samples.

Comparison to Water-Quality Standards

Comparisons of WQS for concentrations of E. coli, enterococci, and FC for wet- and dry-weather samples are provided in

figures 5, 6, and 7, respectively. For wet-weather samples for

enterococci, 56 percent of samples exceeded the USEPA criterion of 33 col/100 mL. For E. coli, 71 percent of samples for wet

weather exceeded the USEPA criterion of 33 col/100 mL.

A total of 81 percent of samples exceeded the PaDEP criterion

for wet weather for FC bacteria samples (table 4).
24 Fecal-Indicator Bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-Sept. 2001

Several dry-weather exceedences for E. coli and FC were

reported in the Allegheny and Monongahela Rivers. The source

stream contributing to the load is unknown. Wet-weather

exceedences were more frequent and were isolated primarily to

the lower reaches of the Allegheny River, the Monongahela,

and Ohio Rivers. Concentrations of three indicator bacteria

were less than the established recreational WQS at Oakmont.

Load Estimates

A convenient way to represent the magnitude of bacteria in

a receiving water is to multiply a concentration by the discharge

rate, which is characteristic of the cross section at the time of

sampling. This magnitude is a measure of the bacteria load

within the receiving water. The USEPA (2001) has developed a

protocol for determining the total maximum daily load (TMDL)

of pathogens such as the fecal-indicator bacteria discussed in

this report.

A TMDL can be used as a tool for implementing state

WQS and is based on the relation between the source of a pollutant (pathogen) and the assimilative capacity of the receiving

water. Ultimately, the TMDL can be used to establish an allowable load for a given pathogen in a water body without exceeding applicable WQS. The information presented in this report

may be helpful to water-resources managers in development of

TMDLs for the Three Rivers region.

Estimated fecal-indicator bacteria loads were established

for each site and are presented in table 8. Loads were calculated

by multiplying the EDI composite concentration by the streamflow measured during the day of sampling and are based on the

following equation:

(1)

Significant increases in loads were observed from Oakmont, the upstream boundary of the study area, to the 9th Street

Bridge, at the confluence of the Allegheny and Ohio Rivers.

This observation was consistent for each of the storms sampled.

The loads established for Sewickley reflect the contribution

from the Monongahela subbasin and source streams along the

Ohio River. Additionally, loads decreased significantly during

days 2, 3, and 4 after storm cessation.

Table 7. Statistically significant relations for fecal-indicator bacteria for dry-, mixed-, and wet-weather samples, July-September 2001,

Allegheny Co unty, Pa.

[ns, p-value greater than 0.10 and is not significant; RB, right-bank sample; LB, left-bank sample; Comp, composite sample]

Water-quality

parameter and

comparison

tested

Allegheny River Monongahela River Ohio River

Oakmont 9th St. Bridge Braddock Pittsburgh Sewickley

Wet Dry Mixed Wet Dry Mixed Wet Dry Mixed Wet Dry Mixed Wet Dry Mixed

Escherichia coli

RB – Comp 0.006 ns ns ns ns ns ns ns ns ns ns ns ns ns ns

LB – Comp .005 0.1 ns ns ns ns ns ns ns ns ns ns 0.04 ns ns

RB – LB ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns

Enterococci

RB – Comp .02 ns ns ns ns 0.007 ns ns ns ns 0.07 ns ns ns ns

LB – Comp .05 ns 0.04 ns ns ns ns ns ns ns .02 ns ns ns ns

RB – LB ns ns ns ns ns .08 ns ns ns ns ns ns ns 0.08 ns

Fecal coliform

RB – Comp .006 ns ns ns ns ns ns ns ns ns ns ns ns ns ns

LB – Comp .003 ns ns ns ns ns ns ns ns ns ns ns ns ns ns

RB – LB ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns

Turbidity

RB – Comp ns ns ns 0.03 ns .04 0.08 0.03 ns 0.003 ns ns ns .08 0.06

LB – Comp ns ns ns .04 0.03 .1 ns .05 ns .04 .03 ns ns ns ns

RB – LB ns ns ns ns ns ns ns .04 ns ns ns ns ns ns ns

Q f t3

s

------- Bacteria colonies

100mL --------------------------------------- mL0.001 L ⋅ ⋅ ----------------- 28.3 L

1ft3 ⋅ -------------- 60 s

min ⋅ --------- 60 min

hr ⋅ ---------------- 24 hr

day ⋅ ------------

Loadfecal-indicator bacteria

colonies

day -------------------=
Table 8. Estimated daily loads of fecal-indicator bacteria within the Allegheny, Monongahela, and Ohio Rivers near Pittsburgh, Pennsylvania, July-Se

U.S. Geological Survey

station

number

Site name Event Date

Streamflow,

in cubic feet

per second

Escherichia

coli,

in colonies

per 100

milliliter

Escherichia

coli load,

in colonies

per day

Enterococci,

in colonies per

100 milliliters

Enterococci

load,

in colonies

per day

Fecin c

100 

03049652 Oakmont Dry 07/24/01 4,040 15 1.E+12 <5 5.E+11 03049652 Oakmont Dry 08/07/01 5,650 15 2.E+12 <5 7.E+11 03049652 Oakmont Dry 09/04/01 3,980 85 8.E+12 <5 5.E+11 03049652 Oakmont Dry 09/18/01 3,630 20 2.E+12 <5 4.E+11 03049832 9th St. Bridge Dry 07/24/01 5,910 140 2.E+13 20 3.E+12 03049832 9th St. Bridge Dry 08/07/01 4,960 20 2.E+12 5 6.E+11 03049832 9th St. Bridge Dry 09/04/01 4,220 < 5 5.E+11 <5 5.E+11 03049832 9th St. Bridge Dry 09/18/01 3,320 5 4.E+11 <5 4.E+11 

03085000 Braddock Dry 09/18/01 2,350 30 2.E+12 5 3.E+11 03085000 Braddock Dry 07/24/01 3,180 120 9.E+12 5 4.E+11 03085000 Braddock Dry 08/07/01 4,720 320 4.E+13 15 2.E+12 

03085000 Braddock Dry 09/04/01 5,120 100 1.E+13 5 6.E+11 03085150 Smithfield St. Bridge Dry 07/24/01 3,180 40 3.E+12 <5 4.E+11 03085150 Smithfield St. Bridge Dry 08/07/01 5,060 30 4.E+12 5 6.E+11 03085150 Smithfield St. Bridge Dry 09/04/01 5,800 180 3.E+13 <5 7.E+11 03085150 Smithfield St. Bridge Dry 09/18/01 2,700 5 3.E+11 5 3.E+11 

03086000 Sewickley Dry 07/24/01 8,300 < 5 1.E+12 10 2.E+12 03086000 Sewickley Dry 08/07/01 11,400 40 1.E+13 15 4.E+12 03086000 Sewickley Dry 09/04/01 9,600 100 2.E+13 <5 1.E+12 

03049652 Oakmont Mixed 07/12/01 4,360 220 2.E+13 5 5.E+11 03049652 Oakmont Mixed 07/18/01 4,150 40 4.E+12 <5 5.E+11 03049652 Oakmont Mixed 07/31/01 4,040 <5 5.E+11 <5 5.E+11 03049652 Oakmont Mixed 08/14/01 3,410 45 4.E+12 <5 4.E+11 03049652 Oakmont Mixed 08/21/01 2,810 20 1.E+12 10 7.E+11 

03049832 9th St. Bridge Mixed 07/12/01 4,130 130 1.E+13 <5 5.E+11 03049832 9th St. Bridge Mixed 07/18/01 4,080 3 3.E+11 5 5.E+11 03049832 9th St. Bridge Mixed 07/31/01 3,530 5 4.E+11 <5 4.E+11 03049832 9th St. Bridge Mixed 08/14/01 4,230 75 8.E+12 <5 5.E+11 03049832 9th St. Bridge Mixed 08/21/01 3,140 <5 4.E+11 <5 4.E+11 

03085000 Braddock Mixed 07/12/01 14,800 < 100 4.E+13 <5 2.E+12 03085000 Braddock Mixed 07/18/01 3,670 120 1.E+13 <5 4.E+11 03085000 Braddock Mixed 07/31/01 21,800 120 6.E+13 30 2.E+13 03085000 Braddock Mixed 08/14/01 11,600 230 7.E+13 15 4.E+12 03085000 Braddock Mixed 08/21/01 3,340 320 3.E+13 45 4.E+12 
U.S. Geological Survey station number Site name Event Date Streamflow, in cubic feet per second Escherichia coli, in colonies per 100 milliliter Escherichia coli load, in colonies per day Enterococci, in colonies per 100 milliliters Enterococci load, in colonies per day Fec

in c

10

03085150 Smithfield St. Bridge Mixed 07/12/01 14,000 290 1.E+14 60 2.E+13 03085150 Smithfield St. Bridge Mixed 07/18/01 3,080 35 3.E+12 <5 4.E+11 03085150 Smithfield St. Bridge Mixed 07/31/01 19,900 10,000 5.E+15 15 7.E+12 03085150 Smithfield St. Bridge Mixed 08/14/01 10,700 75 2.E+13 <5 1.E+12 03085150 Smithfield St. Bridge Mixed 08/21/01 3,030 420 3.E+13 45 3.E+12 

03086000 Sewickley Mixed 07/12/01 22,600 280 2.E+14 45 2.E+13 03086000 Sewickley Mixed 07/18/01 8,200 6 1.E+12 5 1.E+12 03086000 Sewickley Mixed 07/31/01 26,300 20 1.E+13 <5 3.E+12 03086000 Sewickley Mixed 08/14/01 19,600 460 2.E+14 10 5.E+12 03086000 Sewickley Mixed 08/21/01 6,480 10 2.E+12 5 8.E+11 

03049652 Oakmont Wet 08/08/01 3,350 < 5 4.E+11 <5 4.E+11 03049652 Oakmont Wet 08/09/01 3,830 <5 5.E+11 <5 5.E+11 03049652 Oakmont Wet 08/10/01 3,860 20 2.E+12 <5 5.E+11 03049652 Oakmont Wet 08/28/01 4,640 25 3.E+12 <5 6.E+11 03049652 Oakmont Wet 08/29/01 4,040 <5 5.E+11 <5 5.E+11 03049652 Oakmont Wet 08/30/01 4,520 15 2.E+12 25 3.E+12 03049652 Oakmont Wet 09/25/01 3,480 15 1.E+12 <5 4.E+11 03049652 Oakmont Wet 09/27/01 4,350 15 2.E+12 <5 5.E+11 

03049832 9th St. Bridge Wet 08/08/01 4,440 2,700 3.E+14 230 2.E+13 03049832 9th St. Bridge Wet 08/09/01 3,710 440 4.E+13 20 2.E+12 03049832 9th St. Bridge Wet 08/10/01 4,510 6,400 7.E+14 225 2.E+13 03049832 9th St. Bridge Wet 08/28/01 5,220 420 5.E+13 20 3.E+12 03049832 9th St. Bridge Wet 08/29/01 4,890 2,200 3.E+14 265 3.E+13 03049832 9th St. Bridge Wet 08/30/01 4,720 35 4.E+12 100 1.E+13 03049832 9th St. Bridge Wet 09/25/01 3,630 690 6.E+13 5 4.E+11 03049832 9th St. Bridge Wet 09/26/01 5,450 220 3.E+13 10 1.E+12 03049832 9th St. Bridge Wet 09/27/01 3,770 35 3.E+12 5 5.E+11 

03085000 Braddock Wet 08/08/01 5,460 6,000 8.E+14 125 2.E+13 03085000 Braddock Wet 08/09/01 4,210 35 4.E+12 20 2.E+12 03085000 Braddock Wet 08/10/01 3,140 510 4.E+13 15 1.E+12 03085000 Braddock Wet 08/28/01 5,670 520 7.E+13 130 2.E+13 03085000 Braddock Wet 08/29/01 5,650 2,000 3.E+14 250 3.E+13 03085000 Braddock Wet 08/30/01 4,900 50 6.E+12 150 2.E+13 03085000 Braddock Wet 09/25/01 7,770 1,600 3.E+14 220 4.E+13 03085000 Braddock Wet 09/26/01 9,090 90 2.E+13 15 3.E+12 03085000 Braddock Wet 09/27/01 5,400 570 8.E+13 35 5.E+12 

Table 8. Estimated daily loads of fecal-indicator bacteria within the Allegheny, Monongahela, and Ohio Rivers near Pittsburgh, Pennsylvania, July-Se—Continued.
U.S.

Geological

Survey station

number

Site name Event Date

Streamflow,

in cubic feet

per second

Escherichia

coli,

in colonies per

100 milliliter

Escherichia

coli load,

in colonies per

day

Enterococci,

in colonies per

100 milliliters

Enterococci

load, in

colonies per

day

Fec

in c

10

03085150 Smithfield St. Bridge Wet 08/08/01 5,270 1,800 2.E+14 130 2.E+13 03085150 Smithfield St. Bridge Wet 08/09/01 3,800 180 2.E+13 15 1.E+12 03085150 Smithfield St. Bridge Wet 08/10/01 3,010 2,000 1.E+14 195 1.E+13 03085150 Smithfield St. Bridge Wet 08/28/01 5,620 280 4.E+13 20 3.E+12 03085150 Smithfield St. Bridge Wet 08/29/01 5,400 2,300 3.E+14 90 1.E+13 03085150 Smithfield St. Bridge Wet 08/30/01 5,740 260 4.E+13 685 1.E+14 03085150 Smithfield St. Bridge Wet 09/25/01 7,550 960 2.E+14 <5 9.E+11 03085150 Smithfield St. Bridge Wet 09/26/01 9,070 870 2.E+14 5 1.E+12 03085150 Smithfield St. Bridge Wet 09/27/01 2,880 500 4.E+13 10 7.E+11 

03086000 Sewickley Wet 08/08/01 11,600 1,300 4.E+14 350 1.E+14 03086000 Sewickley Wet 08/09/01 8,110 400 8.E+13 115 2.E+13 03086000 Sewickley Wet 08/10/01 8,990 420 9.E+13 70 2.E+13 03086000 Sewickley Wet 08/28/01 14,300 240 8.E+13 10 3.E+12 03086000 Sewickley Wet 08/29/01 13,000 2,300 7.E+14 310 1.E+14 03086000 Sewickley Wet 08/30/01 9,400 2,300 5.E+14 180 4.E+13 03086000 Sewickley Wet 09/26/01 11,500 2,000 6.E+14 20 6.E+12 03086000 Sewickley Wet 09/28/01 8,380 140 3.E+13 15 3.E+12 

Table 8. Estimated daily loads of fecal-indicator bacteria within the Allegheny, Monongahela, and Ohio Rivers near Pittsburgh, Pennsylvania, July-Se—Continued.
28 Fecal-Indicator Bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-Sept. 2001

Summary and Conclusions

The Allegheny County Health Department (ACHD) and

U.S. Geological Survey (USGS) implemented a water-qualitymonitoring program in July through September 2001 to assess

the occurrence and distribution of fecal-indicator bacteria in the

Allegheny, Monongahela, and Ohio Rivers (Three Rivers) near

Pittsburgh, Pa. Water-quality samples were collected and

streamflow measurements were made during dry-, mixed-, and

wet-weather conditions at five sampling sites on the Three Rivers. Water samples were collected weekly to establish baseline

conditions and during successive days after three wet-weather

events.

Samples were collected by the USGS and analyzed by the

ACHD Laboratory for concentrations of fecal coliform (FC),

Escherichia coli (E. coli), and enterococci bacteria. Fecal-indicator bacteria reported in bank and composite samples were

used to evaluate the distribution and mixing of bacteria source

streams within receiving waters such as the Three Rivers. At

each site, left-bank and right-bank samples were collected in

addition to a composite sample (a discharge-weighted sample

representative of the channel cross section as a whole).

Wet-weather concentrations exceeded those reported during dry-weather events for all sites, except the Allegheny River

at Oakmont. At this site, dilution during wet-weather events or

the lack of source streams upgradient of the site may cause this

anomaly. Additionally, based on single-event, water-quality

data, fecal-indicator bacteria concentrations of E. coli and FC

during wet-weather events exceeded State and Federal waterquality standards (WQS). Concentrations of enterococci, E.

coli, and FC during dry-weather events were greater than the

WQS in 11, 28, and 28 percent of the samples, respectively;

during mixed-weather events, concentrations of fecal-indicator

bacteria were greater than the WQS in 28, 37, and 43 percent of

the samples, respectively; and during wet-weather samples,

concentrations of fecal-indicator bacteria were greater than the

WQS in 56, 71, and 81 percent of samples, respectively.

It is difficult to establish a short-term trend in concentrations of fecal-indicator bacteria as a function of time after a wetweather event because of factors including the spatial variability of sources contributing fecal material, dry-weather discharges, resuspension of bottom sediments, and flow augmentation from upstream reservoirs. Relative to E. coli and

enterococci, FC concentrations appear to decrease with time,

which may be attributed to the greater die-off rate for FC bacteria.

Fecal-indicator bacteria concentrations at a station are

dependent on the spatial distribution of point sources upstream

of the station, the time of travel, rate of decay, and the degree of

mixing and resuspension.

In general, the bacteria concentrations in the bank samples

collected at each site were greater than in the composite sample.

This is attributed in part to incomplete mixing of source discharges such as combined sewer overflows/sanitary sewer overflows and tributaries adjacent to the river banks. Depending on

the difference in the momentum between the point source and

the receiving water, the point discharges may be strongly

deflected and have a tendency to hug the side of the receiving

water channel. This is particularly true within the near-field

mixing region, where the jet characteristics of the discharge

(momentum, buoyancy, and outfall geometry) dominate. As the

plume travels downstream, these characteristics become less

important, and the characteristics of the receiving water

(momentum, velocity distribution, channel geometry, buoyant

spreading, and diffusion) dominate the mixing process. The

point at which mixing becomes more uniform is based on the

distribution of additional point discharges downstream and

receiving water hydrodynamics. If conditions are well-mixed,

peak concentrations would be expected to coincide with that

part of a channel where the maximum velocity occurs.

To evaluate the significance of the fecal-indicator bacteria

counts and turbidity reported in grab and composite samples

during dry-, mixed-, and wet-weather events, data sets were

evaluated using Wilcoxon rank sum tests. Tests were conducted

using each of the fecal-indicator bacteria by station and lumped

based on weather event. For example, fecal coliform counts

reported in the left-bank sample were compared against the

right-bank and composite samples, respectively, for the

Sewickley site during dry-, mixed-, and wet-weather events.

The information presented in this report may be helpful to

water-resources managers in development of TMDLs for the

Three Rivers region.

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30 Fecal-Indicator Bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-Sept. 2001

Appendix 1. Summary of Streamflow and Water-Quality Samples

[lat, latitude; long, longitude; mi, mile; mi2, square mile; inst., instantaneous; ft fm r bk, feet from right bank; mg/L, milligram per liter;∝S/cm, microsiemens per centimeter; deg C,

degrees Celsius; ft fm l bank; feet from left bank; NTU, nephelometric turbidity units; col/100 mL, colonies per 100 milliliters; 9, surface-water sample; R, quality-control sample

from surface water; --, no data; <, less than]

03049652 ALLEGHENY RIVER AT OAKMONT, PA

LOCATION.--Lat 40°31'39", long 79°50'51", Allegheny County, Hydrologic Unit 05010009, at Hulton bridge at Oakmont, 0.7 mi downstream from Deer

Creek, at river mile 12.7.

DRAINAGE AREA.--11,577 mi2.

WATER-QUALITY DATA, WATER YEAR OCTOBER 2000 TO SEPTEMBER 2001

 DIS- SAMPLE PH SAMPLE

 CHARGE, LOC- WATER SPE- LOC-

 INST. ATION, WHOLE CIFIC ATION,

 CUBIC CROSS OXYGEN, FIELD CON- TEMPER- CROSS

 MEDIUM FEET SECTION DIS- (STAND- DUCT- ATURE SECTION

 DATE TIME CODE PER (FT FM SOLVED ARD ANCE WATER (FT FM

 SECOND R BK) (MG/L) UNITS) (∝S/CM) (DEG C) L BANK)

 (00061) (72103) (00300) (00400) (00095) (00010) (00009)

 JUL

 12... 1505 9 4360 -- 6.8 7.3 354 27.0 25.0

 12... 1620 9 4360 -- -- 7.5 359 27.5 --

 12... 1630 9 4360 25.0 7.2 7.4 373 27.0 --

 18... 1440 9 4150 40.0 9.8 7.8 411 29.0 --

 18... 1500 9 4150 -- -- 8.0 397 29.0 --

 18... 1510 9 4150 -- 9.8 7.8 383 29.0 30.0

 24... 1440 9 4040 30.0 9.6 7.8 374 29.0 --

 24... 1500 9 4040 -- -- 7.9 384 29.0 --

 24... 1515 9 4040 -- 9.6 7.8 375 29.0 30.0

 31... 1510 9 4040 40.0 9.1 8.1 363 33.0 --

 31... 1530 9 4040 -- -- 7.4 369 33.0 --

 31... 1535 R 4040 -- -- 7.4 369 33.0 --

 31... 1543 9 4040 -- 9.1 7.6 345 33.0 35.0

 AUG

 07... 1430 9 5650 40.0 9.7 8.0 349 32.0 --

 07... 1445 9 5650 -- -- 7.9 352 32.0 --

 07... 1500 9 5650 -- 9.7 7.9 339 32.0 45.0

 08... 1445 9 3350 20.0 10.9 8.0 368 33.0 --

 08... 1500 9 3350 -- -- 8.1 382 33.0 --

 08... 1515 9 3350 -- 10.9 8.0 365 33.0 45.0

 09... 1310 9 3830 40.0 10.4 8.4 393 31.5 --

 09... 1325 9 3830 -- -- 8.0 360 30.1 --

 09... 1330 R 3830 -- -- 8.0 360 30.1 --

 09... 1335 9 3830 -- -- 8.0 368 32.0 45.0

 10... 1440 9 3860 40.0 8.9 8.0 371 31.5 --

 10... 1505 9 3860 -- -- 7.9 376 31.5 --

 10... 1515 9 3860 -- 8.9 8.0 350 31.5 45.0

 14... 1300 9 3410 40.0 9.4 7.8 394 21.0 --

 14... 1330 9 3410 -- -- 7.6 392 28.0 --

 14... 1340 9 3410 -- 9.4 7.8 371 29.0 45.0

 21... 1545 9 2810 40.0 10.2 7.9 397 29.5 --

 21... 1600 9 2810 -- -- 7.8 401 29.5 --

 21... 1610 9 2810 -- 10.2 7.9 387 29.5 20.0

 28... 1540 9 4640 40.0 11.1 7.0 405 23.0 --

 28... 1550 9 4640 -- -- 7.2 392 24.1 --

 28... 1600 9 4640 -- 11.1 7.1 373 24.3 40.0

 29... 1445 9 4040 40.0 12.5 7.1 393 24.5 --

 29... 1500 9 4040 -- -- 7.4 392 27.0 --

 29... 1515 9 4040 -- 12.5 7.3 362 27.0 50.0

 30... 1246 9 4520 40.0 11.3 8.0 399 27.0 --

 30... 1300 9 4520 -- -- 7.4 393 27.0 --

 30... 1310 9 4520 -- 11.3 7.6 386 27.0 50.0

 SEP

 04... 1410 9 3980 40.0 12.2 7.9 382 26.0 --

 04... 1430 9 3980 -- -- 8.0 388 26.5 --

 04... 1440 9 3980 -- 12.2 7.9 360 26.5 50.0

 18... 1300 9 3630 -- 8.6 7.8 288 24.0 40.0

 18... 1400 9 3630 -- -- 7.8 303 28.0 --

 18... 1415 9 3630 45.0 9.4 7.9 293 24.0 --

 25... 1400 9 3480 -- 8.9 7.7 384 22.0 213

 25... 1500 9 3480 -- -- 7.6 399 20.5 --

 25... 1515 9 3480 69.0 9.2 7.8 397 21.5 --

 27... 1405 9 4350 -- 10.0 7.8 358 21.0 150

 27... 1520 9 4350 -- -- 7.8 362 20.0 --

 27... 1530 9 4350 70.0 9.7 7.9 376 21.0 --
Appendix 1 31

03049652 ALLEGHENY RIVER AT OAKMONT, PA—Continued

WATER-QUALITY DATA, WATER YEAR OCTOBER 2000 TO SEPTEMBER 2001

 SAMPLE FECAL SAMPLE

 LOC- ENTERO- COLI- LOC-

 ATION, E COLI, COCCI, FORM, ATION,

 CROSS TUR- MTEC MF ME MF, MFC MF, CROSS

 MEDIUM SECTION BID- WATER WATER WATER SECTION

 DATE CODE (FT FM ITY (COL/ (COL/ (COL/ (FT FM

 R BK) (NTU) 100 ML) 100 ML) 100 ML) L BANK)

 (72103) (00076) (31633) (31649) (31616) (00009)

 JUL

 12... 9 -- 7.4 10 5 90 25.0

 12... 9 -- 10 220 5 210 --

 12... 9 25.0 6.2 20 <5 100 --

 18... 9 40.0 4.8 20 30 45 --

 18... 9 -- 3.8 40 <5 25 --

 18... 9 -- 6.1 95 35 85 30.0

 24... 9 30.0 -- 10 5 30 --

 24... 9 -- -- 15 <5 30 --

 24... 9 -- -- 180 75 230 30.0

 31... 9 40.0 4.8 15 <5 55 --

 31... 9 -- 6.9 <5 <5 <5 --

 31... R -- 6.9 <5 <5 <5 --

 31... 9 -- 6.8 35 40 30 35.0

 AUG

 07... 9 40.0 3.7 35 5 75 --

 07... 9 -- 7.3 15 <5 40 --

 07... 9 -- 3.7 40 5 35 45.0

 08... 9 20.0 8.3 25 <5 15 --

 08... 9 -- 6.2 <5 <5 <5 --

 08... 9 -- 8.3 20 30 35 45.0

 09... 9 40.0 4.6 10 15 30 --

 09... 9 -- 4.6 <5 <5 5 --

 09... R -- 4.6 <5 <5 <5 --

 09... 9 -- 5.9 15 <5 65 45.0

 10... 9 40.0 4.6 60 45 100 --

 10... 9 -- 6.3 20 <5 35 --

 10... 9 -- 5.4 55 20 120 45.0

 14... 9 40.0 3.6 5 <5 70 --

 14... 9 -- 4.5 45 <5 65 --

 14... 9 -- 3.5 M 20 280 45.0

 21... 9 40.0 6.2 25 50 50 --

 21... 9 -- 5.8 20 10 30 --

 21... 9 -- 6.8 130 20 210 20.0

 28... 9 40.0 8.6 820 690 960 --

 28... 9 -- 7.4 25 <5 50 --

 28... 9 -- 9.9 370 240 660 40.0

 29... 9 40.0 10 60 80 45 --

 29... 9 -- 9.0 <5 <5 5 --

 29... 9 -- 6.1 400 40 410 50.0

 30... 9 40.0 6.5 140 75 180 --

 30... 9 -- 7.8 15 25 10 --

 30... 9 -- 6.9 55 20 220 50.0

 SEP

 04... 9 40.0 7.8 110 20 330 --

 04... 9 -- 9.4 85 <5 75 --

 04... 9 -- 9.9 140 5 130 50.0

 18... 9 -- 5.7 40 10 20 40.0

 18... 9 -- 5.6 20 <5 20 --

 18... 9 45.0 6.1 30 <5 60 --

 25... 9 -- 7.0 55 5 270 213

 25... 9 -- 7.8 15 <5 5 --

 25... 9 69.0 8.7 130 20 320 --

 27... 9 -- 5.7 35 <5 33 150

 27... 9 -- 7.3 15 <5 15 --

 27... 9 70.0 5.7 45 5 95 --
32 Fecal-Indicator Bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-Sept. 2001

03049832 ALLEGHENY RIVER AT 9TH STREET BRIDGE AT PITTSBURGH, PA

LOCATION.--Lat 40°26'47", long 79°59'58", Allegheny County, Hydrologic Unit 05010009, at 9th Street bridge in Pittsburgh, at river mile 0.7.

DRAINAGE AREA.--11,710 mi2.

WATER-QUALITY DATA, WATER YEAR OCTOBER 2000 TO SEPTEMBER 2001

 DIS- SAMPLE PH SAMPLE

 CHARGE, LOC- WATER SPE- LOC-

 INST. ATION, WHOLE CIFIC ATION,

 CUBIC CROSS OXYGEN, FIELD CON- TEMPER- CROSS

 MEDIUM FEET SECTION DIS- (STAND- DUCT- ATURE SECTION

 DATE TIME CODE PER (FT FM SOLVED ARD ANCE WATER (FT FM

 SECOND R BK) (MG/L) UNITS) (∝S/CM) (DEG C) L BANK)

 (00061) (72103) (00300) (00400) (00095) (00010) (00009)

 JUL

 12... 1050 9 4130 -- 6.6 7.5 358 26.0 20.0

 12... 1110 9 4130 -- 7.7 7.4 358 26.0 --

 12... 1135 9 4130 20.0 7.2 7.4 366 26.0 --

 18... 1000 9 4080 -- 7.3 7.4 399 26.5 20.0

 18... 1100 9 4080 -- 7.3 7.5 401 26.5 --

 18... 1110 9 4080 20.0 6.6 7.5 405 26.5 --

 24... 1005 9 5910 -- 6.7 7.4 375 28.0 20.0

 24... 1120 9 5910 -- 7.6 7.6 376 28.5 --

 24... 1125 9 5910 20.0 6.6 7.4 380 28.5 --

 31... 1140 9 3530 -- 7.6 7.6 396 27.5 20.0

 31... 1300 9 3530 -- -- 7.3 396 29.0 --

 31... 1320 9 3530 20.0 7.9 8.1 396 27.0 --

 AUG

 07... 1000 9 4960 -- 7.1 7.2 364 28.5 25.0

 07... 1127 9 4960 -- -- 7.4 364 29.0 --

 07... 1135 9 4960 20.0 7.0 7.8 366 29.0 --

 08... 1130 9 4440 -- 6.8 7.7 343 29.5 20.0

 08... 1220 9 4440 20.0 6.4 7.5 358 29.5 --

 08... 1300 9 4440 -- -- 7.4 346 29.5 --

 09... 1000 9 3710 -- 6.3 7.2 353 29.0 30.0

 09... 1100 9 3710 -- -- 7.5 350 30.0 --

 09... 1110 9 3710 20.0 6.3 7.8 350 29.5 --

 10... 1010 9 4510 -- 7.4 7.8 354 29.0 20.0

 10... 1030 9 4510 -- -- 8.1 355 29.0 --

 10... 1050 9 4510 20.0 7.4 8.1 358 29.0 --

 14... 1050 9 4230 -- 7.5 7.4 374 29.0 25.0

 14... 1120 9 4230 -- -- 7.6 375 29.0 --

 14... 1135 9 4230 25.0 8.4 7.5 380 29.0 --

 21... 1205 9 3140 -- 8.1 7.9 369 27.0 25.0

 21... 1305 9 3140 -- -- 8.0 370 27.0 --

 21... 1310 R 3140 -- -- 8.0 370 27.0 --

 21... 1315 9 3140 25.0 8.2 8.0 369 27.0 --

 28... 1052 9 5220 -- 9.5 6.5 388 27.0 20.0

 28... 1130 9 5220 -- -- 7.2 387 27.5 --

 28... 1205 9 5220 20.0 9.3 6.4 389 27.5 --

 29... 1245 9 4890 -- 7.9 -- 394 26.5 25.0

 29... 1350 9 4890 -- -- -- 391 27.0 --

 29... 1400 9 4890 25.0 8.5 -- 391 27.5 --

 30... 1215 9 4720 -- 9.1 7.9 415 27.0 30.0

 30... 1320 9 4720 -- -- 7.9 416 27.0 --

 30... 1325 9 4720 25.0 9.0 7.8 426 27.5 --

 SEP

 04... 1100 9 4220 -- 8.7 7.1 346 25.5 30.0

 04... 1145 9 4220 -- -- 7.8 345 26.0 --

 04... 1150 9 4220 30.0 9.2 7.2 348 26.0 --

 18... 1135 9 3320 -- 9.5 7.9 304 23.0 30.0

 18... 1200 9 3320 -- -- 7.9 305 23.0 --

 18... 1210 9 3320 30.0 8.9 7.8 306 23.0 --

 25... 1015 9 3630 -- 8.1 7.5 436 22.0 55.0

 25... 1050 9 3630 -- -- 7.6 442 20.5 --

 25... 1100 9 3630 40.0 7.9 7.5 443 22.0 --

 26... 1355 9 5450 -- 9.1 7.8 451 20.0 60.0

 26... 1410 9 5450 40.0 9.2 7.7 450 20.0 --

 26... 1425 9 5450 -- -- 7.8 450 21.5 --

 26... 1425 R 5450 -- -- 7.8 450 20.5 --

 27... 1230 9 3770 -- 10.4 7.7 420 19.5 40.0

 27... 1250 9 3770 40.0 9.9 7.7 421 20.0 --

 27... 1310 9 3770 -- -- 7.6 418 19.5 --

 27... 1310 R 3770 -- -- 7.6 418 19.5 --
Appendix 1 33

03049832 ALLEGHENY RIVER AT 9TH STREET BRIDGE AT PITTSBURGH, PA—Continued

WATER-QUALITY DATA, WATER YEAR OCTOBER 2000 TO SEPTEMBER 2001

 SAMPLE FECAL SAMPLE

 LOC- ENTERO- COLI- LOC-

 ATION, E COLI, COCCI, FORM, ATION,

 CROSS TUR- MTEC MF ME MF, MFC MF, CROSS

 MEDIUM SECTION BID- WATER WATER WATER SECTION

 DATE CODE (FT FM ITY (COL/ (COL/ (COL/ (FT FM

 R BK) (NTU) 100 ML) 100 ML) 100 ML) L BANK)

 (72103) (00076) (31633) (31649) (31616) (00009)

 JUL

 12... 9 -- 7.5 70 20 180 20.0

 12... 9 -- 9.8 130 <5 180 --

 12... 9 20.0 5.8 65 10 160 --

 18... 9 -- 7.7 9 <5 110 20.0

 18... 9 -- 13 3 5 55 --

 18... 9 20.0 6.7 45 15 40 --

 24... 9 -- 5.1 230 35 460 20.0

 24... 9 -- 6.9 140 20 290 --

 24... 9 20.0 4.5 45 40 130 --

 31... 9 -- 4.5 10 <5 40 20.0

 31... 9 -- 7.8 5 <5 25 --

 31... 9 20.0 5.1 35 25 60 --

 AUG

 07... 9 -- 4.2 <5 10 70 25.0

 07... 9 -- 6.5 20 5 30 --

 07... 9 20.0 3.1 45 5 55 --

 08... 9 -- 3.4 2900 200 7600 20.0

 08... 9 20.0 2.9 600 150 1600 --

 08... 9 -- 5.6 2700 230 4400 --

 09... 9 -- 6.1 1800 85 1600 30.0

 09... 9 -- 7.9 440 20 560 --

 09... 9 20.0 4.9 900 50 150 --

 10... 9 -- 3.6 240 575 230 20.0

 10... 9 -- 120 6400 225 14000 --

 10... 9 20.0 3.3 4200 220 21000 --

 14... 9 -- 3.4 85 5 200 25.0

 14... 9 -- 5.6 75 <5 85 --

 14... 9 25.0 3.7 160 15 6900 --

 21... 9 -- 4.4 160 5 260 25.0

 21... 9 -- 7.1 <5 <5 <5 --

 21... R -- -- <5 <5 5 --

 21... 9 25.0 3.7 60 10 280 --

 28... 9 -- 6.0 460 25 1500 20.0

 28... 9 -- 6.0 420 20 750 --

 28... 9 20.0 5.6 160 60 650 --

 29... 9 -- 9.8 280 200 5100 25.0

 29... 9 -- 17 2200 265 3300 --

 29... 9 25.0 9.9 2000 360 3700 --

 30... 9 -- 4.7 440 65 620 30.0

 30... 9 -- 9.9 35 100 540 --

 30... 9 25.0 6.2 30 110 640 --

 SEP

 04... 9 -- 6.2 140 10 420 30.0

 04... 9 -- 11 <5 <5 15 --

 04... 9 30.0 7.6 190 <5 360 --

 18... 9 -- 5.3 40 5 35 30.0

 18... 9 -- 8.2 5 <5 5 --

 18... 9 30.0 4.5 25 15 50 --

 25... 9 -- 8.1 5200 525 11000 55.0

 25... 9 -- 12 690 5 880 --

 25... 9 40.0 8.8 7900 380 10000 --

 26... 9 -- 7.0 400 20 690 60.0

 26... 9 40.0 6.9 730 20 830 --

 26... 9 -- 7.6 220 10 580 --

 26... R -- 7.6 150 <5 540 --

 27... 9 -- 5.6 65 5 140 40.0

 27... 9 40.0 5.5 120 5 160 --

 27... 9 -- 7.0 35 5 90 --

 27... R -- 7.0 45 <5 120 --
34 Fecal-Indicator Bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-Sept. 2001

03085000 MONONGAHELA RIVER AT BRADDOCK, PA

LOCATION.--Lat 40°23'28", long 79°51'30", Allegheny County, Hydrologic Unit 05020005, 300 ft upstream from dam at lock 2 at Braddock, 1,700 ft

downstream from Turtle Creek, and 11.2 mi upstream of confluence with Allegheny River.

DRAINAGE AREA.--7,337 mi2.

WATER-QUALITY DATA, WATER YEAR OCTOBER 2000 TO SEPTEMBER 2001

 DIS- SAMPLE PH SAMPLE

 CHARGE, LOC- WATER SPE- LOC-

 INST. ATION, WHOLE CIFIC ATION,

 CUBIC CROSS OXYGEN, FIELD CON- TEMPER- CROSS

 MEDIUM FEET SECTION DIS- (STAND- DUCT- ATURE SECTION

 DATE TIME CODE PER (FT FM SOLVED ARD ANCE WATER (FT FM

 SECOND R BK) (MG/L) UNITS) (∝S/CM) (DEG C) L BANK)

 (00061) (72103) (00300) (00400) (00095) (00010) (00009)

 JUL

 12... 1510 9 14800 -- 7.8 7.5 298 27.0 40.0

 12... 1530 9 14800 -- -- 7.8 323 25.5 --

 12... 1540 9 14800 40.0 7.8 7.6 287 25.5 --

 18... 1435 9 3670 30.0 6.7 7.7 389 27.0 --

 18... 1530 9 3670 -- -- 7.6 387 27.5 --

 18... 1540 9 3670 -- 6.7 7.8 385 26.5 40.0

 24... 1405 9 3180 -- 6.5 7.5 314 28.5 40.0

 24... 1500 9 3180 -- -- 7.4 321 29.0 --

 24... 1510 9 3180 30.0 7.3 7.6 321 28.0 --

 31... 0840 9 21800 -- 7.7 7.0 275 24.5 20.0

 31... 1005 9 21800 20.0 7.7 7.2 275 25.0 --

 31... 1040 9 21800 -- -- 7.3 262 26.0 --

 AUG

 07... 0810 9 4720 -- 6.7 7.4 300 26.0 20.0

 07... 0850 9 4720 20.0 6.6 7.4 297 26.0 --

 07... 0910 9 4720 -- -- 7.6 298 26.5 --

 08... 1000 9 5460 -- 7.0 7.5 308 27.0 50.0

 08... 1030 9 5460 -- -- 7.5 307 27.5 --

 08... 1040 9 5460 20.0 6.5 7.6 313 27.0 --

 09... 0830 9 4210 -- 6.2 7.2 317 28.5 25.0

 09... 0855 9 4210 -- -- 7.4 320 28.5 --

 09... 0902 9 4210 25.0 6.2 7.4 322 28.5 --

 10... 0815 9 3140 -- 7.3 7.8 319 28.5 25.0

 10... 0840 9 3140 -- -- 7.9 327 28.0 --

 10... 0900 9 3140 40.0 6.6 7.6 324 28.5 --

 14... 0830 9 11600 -- 8.5 7.7 300 27.0 25.0

 14... 0945 9 11600 -- -- 7.7 296 27.0 --

 14... 1000 9 11600 25.0 8.2 7.7 308 27.5 --

 21... 0925 9 3340 -- 8.0 7.6 306 25.0 25.0

 21... 1025 9 3340 -- -- 7.7 305 25.0 --

 21... 1035 9 3340 25.0 7.8 7.5 308 25.0 --

 28... 0845 9 5670 -- 8.7 7.9 339 27.0 20.0

 28... 0950 9 5670 -- -- 8.0 337 27.5 --

 28... 1010 9 5670 50.0 8.0 7.0 337 29.0 --

 29... 1020 9 5650 -- 7.9 7.4 330 27.5 25.0

 29... 1120 9 5650 -- -- 7.5 329 27.5 --

 29... 1130 9 5650 25.0 7.6 7.4 332 28.0 --

 30... 0940 9 4900 -- 7.8 7.2 347 26.5 25.0

 30... 1035 9 4900 -- -- 7.4 353 26.5 --

 30... 1045 9 4900 60.0 7.4 7.2 351 26.5 --

 SEP

 04... 0900 9 5120 -- 8.4 7.9 408 26.5 30.0

 04... 1000 9 5120 -- -- 7.6 404 26.5 --

 04... 1015 9 5120 30.0 7.5 7.4 410 26.5 --

 18... 0810 9 2350 -- 8.2 7.6 328 23.0 30.0

 18... 0915 9 2350 -- -- 7.6 337 22.5 --

 18... 0930 9 2350 30.0 8.0 7.6 331 23.0 --

 25... 0845 9 7770 -- 8.5 7.4 419 22.5 25.0

 25... 0915 9 7770 30.0 8.2 7.6 426 21.5 --

 25... 0930 9 7770 -- -- 7.5 418 21.0 --

 25... 0935 R 7770 -- -- 7.5 418 21.0 --

 26... 1230 9 9090 -- 8.7 7.5 438 22.5 25.0

 26... 1250 9 9090 30.0 8.3 7.5 443 22.5 --

 26... 1315 9 9090 -- -- 7.6 436 22.0 --

 27... 0930 9 5400 -- 9.9 7.5 446 20.0 25.0

 27... 1000 9 5400 40.0 9.8 7.6 445 20.0 --

 27... 1010 9 5400 -- -- 7.6 446 19.5 --
Appendix 1 35

03085000 MONONGAHELA RIVER AT BRADDOCK, PA—Continued

WATER-QUALITY DATA, WATER YEAR OCTOBER 2000 TO SEPTEMBER 2001

 SAMPLE FECAL SAMPLE

 LOC- ENTERO- COLI- LOC-

 ATION, E COLI, COCCI, FORM, ATION,

 CROSS TUR- MTEC MF ME MF, MFC MF, CROSS

 MEDIUM SECTION BID- WATER WATER WATER SECTION

 DATE CODE (FT FM ITY (COL/ (COL/ (COL/ (FT FM

 R BK) (NTU) 100 ML) 100 ML) 100 ML) L BANK)

 (72103) (00076) (31633) (31649) (31616) (00009)

 JUL

 12... 9 -- -- 380 85 70 40.0

 12... 9 -- -- <100 <5 <5 --

 12... 9 40.0 -- 20 30 850 --

 18... 9 30.0 15 120 <5 160 --

 18... 9 -- 14 120 <5 160 --

 18... 9 -- 12 80 <5 65 40.0

 24... 9 -- 11 80 10 260 40.0

 24... 9 -- 15 120 5 170 --

 24... 9 30.0 10 40 <5 100 --

 31... 9 -- 75 45 35 300 20.0

 31... 9 20.0 30 45 15 170 --

 31... 9 -- 45 120 30 260 --

 AUG

 07... 9 -- 12 960 20 340 20.0

 07... 9 20.0 10 140 15 290 --

 07... 9 -- 13 320 15 520 --

 08... 9 -- 14 400 50 760 50.0

 08... 9 -- 14 6000 125 8000 --

 08... 9 20.0 10 12000 630 14000 --

 09... 9 -- 15 280 130 850 25.0

 09... 9 -- 16 35 20 90 --

 09... 9 25.0 12 420 30 850 --

 10... 9 -- 4.9 1100 55 1400 25.0

 10... 9 -- 7.9 510 15 840 --

 10... 9 40.0 5.4 11000 530 23000 --

 14... 9 -- 14 320 <5 760 25.0

 14... 9 -- 16 230 15 680 --

 14... 9 25.0 10 140 20 220 --

 21... 9 -- 9.7 290 35 440 25.0

 21... 9 -- 14 320 45 640 --

 21... 9 25.0 9.7 360 60 580 --

 28... 9 -- 14 100 45 450 20.0

 28... 9 -- 15 520 130 1500 --

 28... 9 50.0 13 200 90 1100 --

 29... 9 -- 14 2000 190 1600 25.0

 29... 9 -- 15 2000 250 1700 --

 29... 9 25.0 14 1100 335 2300 --

 30... 9 -- 19 60 185 6400 25.0

 30... 9 -- 20 50 150 740 --

 30... 9 60.0 18 50 155 710 --

 SEP

 04... 9 -- 12 <5 <5 100 30.0

 04... 9 -- 13 100 5 160 --

 04... 9 30.0 7.6 40 <5 150 --

 18... 9 -- 13 170 15 130 30.0

 18... 9 -- 14 30 5 40 --

 18... 9 30.0 11 120 5 140 --

 25... 9 -- 12 440 30 640 25.0

 25... 9 30.0 13 2600 175 19000 --

 25... 9 -- 18 1600 220 15000 --

 25... R -- 18 1400 370 19000 --

 26... 9 -- 16 1000 10 1800 25.0

 26... 9 30.0 14 760 35 730 --

 26... 9 -- 17 90 15 250 --

 27... 9 -- 11 860 15 310 25.0

 27... 9 40.0 11 480 30 320 --

 27... 9 -- 12 570 35 320 --
36 Fecal-Indicator Bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-Sept. 2001

03085150 MONONGAHELA RIVER AT PITTSBURGH, PA

LOCATION.--Lat 40°26'06", long 80°00'08", Allegheny County, Hydrologic Unit 05020005, at Smithfield Street bridge in Pittsburgh, at river mile 0.8.

DRAINAGE AREA.--7,367 mi2.

WATER-QUALITY DATA, WATER YEAR OCTOBER 2000 TO SEPTEMBER 2001

 DIS- SAMPLE PH SAMPLE

 CHARGE, LOC- WATER SPE- LOC-

 INST. ATION, WHOLE CIFIC ATION,

 CUBIC CROSS OXYGEN, FIELD CON- TEMPER- CROSS

 MEDIUM FEET SECTION DIS- (STAND- DUCT- ATURE SECTION

 DATE TIME CODE PER (FT FM SOLVED ARD ANCE WATER (FT FM

 SECOND R BK) (MG/L) UNITS) (∝S/CM) (DEG C) L BANK)

 (00061) (72103) (00300) (00400) (00095) (00010) (00009)

 JUL

 12... 1325 9 14000 -- -- 7.5 260 24.0 --

 12... 1330 9 14000 35.0 6.7 7.6 269 24.5 --

 18... 1210 9 3080 -- 7.2 7.7 317 25.0 60.0

 18... 1310 9 3080 -- -- 7.6 315 26.0 --

 18... 1315 9 3080 20.0 7.4 7.5 315 25.0 --

 24... 1240 9 3180 -- 7.1 7.9 316 28.0 30.0

 24... 1325 9 3180 -- -- 7.8 312 30.0 --

 24... 1330 9 3180 20.0 7.1 7.6 315 28.0 --

 31... 1400 9 19900 -- 7.1 7.3 278 25.0 30.0

 31... 1450 9 19900 -- -- 7.2 279 26.0 --

 31... 1510 9 19900 20.0 7.2 7.2 290 25.0 --

 AUG

 07... 1230 9 5060 -- 7.1 7.7 303 26.0 20.0

 07... 1325 9 5060 -- -- 7.7 300 27.0 --

 07... 1345 9 5060 20.0 7.5 7.7 301 27.0 --

 08... 1410 9 5270 -- 7.6 7.7 293 28.0 20.0

 08... 1440 9 5270 -- -- 7.6 292 27.0 --

 08... 1445 9 5270 20.0 6.5 7.9 288 27.0 --

 09... 1225 9 3800 -- 7.0 7.6 300 28.0 20.0

 09... 1315 9 3800 25.0 7.0 7.6 300 28.0 --

 09... 1350 9 3800 -- -- 7.2 298 29.0 --

 10... 1140 9 3010 -- 8.0 7.6 307 28.0 30.0

 10... 1200 9 3010 -- -- 7.6 307 28.0 --

 10... 1220 9 3010 30.0 7.9 7.7 307 28.0 --

 14... 1300 9 10700 -- 7.6 7.2 313 29.0 30.0

 14... 1400 9 10700 -- -- 7.2 309 29.0 --

 14... 1415 9 10700 30.0 7.4 7.3 311 29.0 --

 21... 1400 9 3030 -- 8.2 7.6 298 26.0 57.0

 21... 1445 9 3030 -- 8.3 7.6 298 26.0 --

 21... 1500 9 3030 25.0 8.3 7.6 298 26.0 --

 28... 1300 9 5620 -- 8.5 4.6 336 27.0 20.0

 28... 1355 9 5620 -- -- 4.8 336 27.0 --

 28... 1400 9 5620 20.0 8.9 5.4 336 27.0 --

 29... 1430 9 5400 -- 7.8 7.2 337 27.0 20.0

 29... 1525 9 5400 -- -- 7.2 331 28.0 --

 29... 1530 R 5400 -- -- 7.2 331 28.0 --

 29... 1535 9 5400 20.0 7.3 7.2 343 28.0 --

 30... 1400 9 5740 -- 7.8 7.4 331 28.0 20.0

 30... 1450 9 5740 -- -- 7.6 328 28.0 --

 30... 1500 9 5740 20.0 7.9 7.6 326 28.0 --

 SEP

 04... 1300 9 5800 -- 8.1 7.1 406 26.0 30.0

 04... 1350 9 5800 -- -- 7.5 407 26.0 --

 04... 1400 9 5800 30.0 8.3 7.8 407 26.0 --

 18... 1000 9 2700 -- 9.4 8.2 352 24.0 30.0

 18... 1045 9 2700 -- -- 8.0 357 24.0 --

 18... 1055 9 2700 30.0 9.4 8.2 353 24.0 --

 25... 1120 9 7550 -- 7.9 7.5 484 23.0 40.0

 25... 1145 9 7550 50.0 7.9 7.5 486 23.0 --

 25... 1205 9 7550 -- -- 7.6 485 22.0 --

 26... 1445 9 9070 -- 8.3 7.7 439 21.0 60.0

 26... 1500 9 9070 70.0 8.3 7.8 444 21.0 --

 26... 1530 9 9070 -- -- 7.6 450 21.0 --

 27... 1050 9 2880 -- 8.7 7.3 444 21.0 60.0

 27... 1055 R 2880 -- 8.7 7.3 444 21.0 60.0

 27... 1110 9 2880 60.0 8.9 7.4 445 21.0 --

 27... 1130 9 2880 -- -- 7.4 445 21.0 --
Appendix 1 37

03085150 MONONGAHELA RIVER AT PITTSBURGH, PA—Continued

WATER-QUALITY DATA, WATER YEAR OCTOBER 2000 TO SEPTEMBER 2001

 SAMPLE FECAL SAMPLE

 LOC- ENTERO- COLI- LOC-

 ATION, E COLI, COCCI, FORM, ATION,

 CROSS TUR- MTEC MF ME MF, MFC MF, CROSS

 MEDIUM SECTION BID- WATER WATER WATER SECTION

 DATE CODE (FT FM ITY (COL/ (COL/ (COL/ (FT FM

 R BK) (NTU) 100 ML) 100 ML) 100 ML) L BANK)

 (72103) (00076) (31633) (31649) (31616) (00009)

 JUL

 12... 9 -- 45 290 60 440 --

 12... 9 35.0 22 1000 150 1600 --

 18... 9 -- 8.7 84 10 70 60.0

 18... 9 -- 14 35 <5 35 --

 18... 9 20.0 11 80 5 55 --

 24... 9 -- 6.2 590 15 500 30.0

 24... 9 -- 9.5 40 <5 70 --

 24... 9 20.0 6.3 30 <5 60 --

 31... 9 -- 40 130 30 200 30.0

 31... 9 -- 55 K10000 15 160 --

 31... 9 20.0 23 75 20 110 --

 AUG

 07... 9 -- 9.2 220 25 260 20.0

 07... 9 -- 11 30 5 120 --

 07... 9 20.0 7.8 60 10 80 --

 08... 9 -- 8.3 1400 55 2400 20.0

 08... 9 -- 9.9 1800 130 3500 --

 08... 9 20.0 6.1 1000 55 2100 --

 09... 9 -- 5.4 180 30 180 20.0

 09... 9 25.0 5.4 180 30 180 --

 09... 9 -- 14 180 15 3400 --

 10... 9 -- 4.9 2400 65 2900 30.0

 10... 9 -- 7.9 2000 195 2800 --

 10... 9 30.0 5.4 1900 350 5900 --

 14... 9 -- 6.8 240 65 820 30.0

 14... 9 -- 16 75 <5 80 --

 14... 9 30.0 7.7 240 5 240 --

 21... 9 -- 7.6 180 35 230 57.0

 21... 9 -- 8.5 420 45 670 --

 21... 9 25.0 8.5 420 45 670 --

 28... 9 -- 7.1 290 30 900 20.0

 28... 9 -- 39 280 20 650 --

 28... 9 20.0 7.7 220 5 540 --

 29... 9 -- 11 750 235 3600 20.0

 29... 9 -- 12 2300 90 2600 --

 29... R -- 12 140 60 1900 --

 29... 9 20.0 10 39000 1060 50000 --

 30... 9 -- 10 70 85 620 20.0

 30... 9 -- 14 260 685 3900 --

 30... 9 20.0 7.5 100 60 680 --

 SEP

 04... 9 -- 8.9 3100 40 3100 30.0

 04... 9 -- 12 180 <5 740 --

 04... 9 30.0 12 9200 150 13000 --

 18... 9 -- 8.1 25 10 75 30.0

 18... 9 -- 13 5 5 10 --

 18... 9 30.0 6.9 40 10 45 --

 25... 9 -- 9.8 1900 65 18000 40.0

 25... 9 50.0 9.4 1600 10 16000 --

 25... 9 -- 12 960 <5 810 --

 26... 9 -- 12 1300 35 2800 60.0

 26... 9 70.0 8.6 340 20 620 --

 26... 9 -- 11 870 5 880 --

 27... 9 -- 9.2 260 10 280 60.0

 27... R -- 9.2 320 5 270 60.0

 27... 9 60.0 7.2 240 15 180 --

 27... 9 -- 8.7 500 10 230 --
38 Fecal-Indicator Bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-Sept. 2001

03086000 OHIO RIVER AT SEWICKLEY, PA

LOCATION.--Lat 40°32'57", long 80°12'21", Allegheny County, Hydrologic Unit 05030101, 50 ft upstream from Dashields Dam, 1.0 mi downstream from

Narrows Run, 1.0 mi northwest of Sewickley, and 13.3 mi downstream from confluence of Allegheny and Monongahela Rivers.

DRAINAGE AREA.--19,500 mi2, approximately.

WATER-QUALITY DATA, WATER YEAR OCTOBER 2000 TO SEPTEMBER 2001

 DIS- SAMPLE PH SAMPLE

 CHARGE, LOC- WATER SPE- LOC-

 INST. ATION, WHOLE CIFIC ATION,

 CUBIC CROSS OXYGEN, FIELD CON- TEMPER- CROSS

 MEDIUM FEET SECTION DIS- (STAND- DUCT- ATURE SECTION

 DATE TIME CODE PER (FT FM SOLVED ARD ANCE WATER (FT FM

 SECOND R BK) (MG/L) UNITS) (∝S/CM) (DEG C) L BANK)

 (00061) (72103) (00300) (00400) (00095) (00010) (00009)

 JUL

 12... 1010 9 22600 -- -- 7.7 349 26.0 20.0

 12... 1100 9 22600 -- -- 7.7 340 26.0 --

 12... 1115 9 22600 20.0 -- 7.6 350 27.0 --

 18... 1005 9 8200 -- 9.4 7.9 382 26.0 50.0

 18... 1015 9 8200 -- -- 7.7 387 26.0 --

 18... 1030 9 8200 35.0 -- 7.8 384 26.0 --

 24... 0940 9 8300 -- 9.0 7.9 372 28.5 50.0

 24... 0950 9 8300 1000 -- 8.0 372 28.5 --

 24... 1000 9 8300 740.0 -- 8.0 370 28.5 --

 24... 1010 9 8300 480.0 -- 8.0 367 28.5 --

 24... 1020 9 8300 250.0 -- 8.0 361 28.5 --

 24... 1030 9 8300 -- -- 8.0 370 28.5 --

 24... 1035 9 8300 50.0 -- 7.9 360 28.5 --

 31... 0955 9 26300 -- 9.8 7.8 292 28.0 30.0

 31... 1025 9 26300 -- -- 7.8 306 28.0 --

 31... 1043 9 26300 25.0 -- 7.9 310 27.5 --

 AUG

 07... 1000 9 11400 -- 9.8 7.6 318 28.0 65.0

 07... 1020 9 11400 -- -- 7.7 328 26.0 --

 07... 1045 9 11400 20.0 -- 7.7 328 28.0 --

 08... 1000 9 11600 -- -- 7.9 360 28.5 65.0

 08... 1015 9 11600 -- -- 8.0 345 28.5 --

 08... 1040 9 11600 20.0 10.7 7.8 358 28.5 --

 09... 0930 9 8110 -- 9.5 7.9 368 31.5 65.0

 09... 0950 9 8110 -- -- 7.8 355 32.0 --

 09... 0958 9 8110 40.0 -- 7.7 348 31.0 --

 10... 1005 9 8990 -- 9.4 7.8 363 31.5 60.0

 10... 1100 9 8990 -- -- 7.7 353 31.5 --

 10... 1110 9 8990 40.0 -- 7.6 336 31.5 --

 14... 0850 9 19600 -- 9.2 7.2 365 20.5 40.0

 14... 0910 9 19600 -- -- 7.3 352 19.5 --

 14... 0925 9 19600 40.0 -- 7.4 351 19.5 --

 21... 1235 9 6480 -- 7.2 7.2 375 17.5 70.0

 21... 1250 9 6480 -- -- 7.4 367 17.5 --

 21... 1305 9 6480 40.0 -- 7.6 364 17.5 --

 28... 0950 9 14300 -- 10.7 6.7 390 27.0 50.0

 28... 0956 9 14300 1010 -- 6.9 387 27.0 --

 28... 1010 9 14300 750.0 -- 6.9 387 27.0 --

 28... 1015 9 14300 -- -- 6.9 387 27.0 --

 28... 1020 9 14300 480.0 -- 6.9 387 27.0 --

 28... 1025 9 14300 250.0 -- 6.9 387 27.0 --

 28... 1035 9 14300 20.0 -- 6.5 396 27.0 --

 29... 0942 9 13000 -- 10.9 7.3 361 30.0 30.0

 29... 1000 9 13000 -- -- 7.5 357 26.0 --

 29... 1020 9 13000 60.0 -- 7.6 347 30.5 --

 30... 0915 9 9400 -- 10.1 7.5 377 26.0 50.0

 30... 0930 9 9400 -- -- 7.6 372 26.0 --

 30... 0940 9 9400 40.0 -- 7.5 368 26.0 --

 SEP

 04... 0955 9 9600 -- 9.9 6.8 407 22.5 60.0

 04... 1015 9 9600 -- -- 7.0 392 26.0 --

 04... 1025 9 9600 50.0 -- 7.0 393 26.0 --

 26... 0900 9 11500 -- 8.8 7.6 455 21.0 50.0

 26... 1010 9 11500 -- -- 7.6 457 21.0 243

 26... 1017 9 11500 -- -- 7.6 457 21.0 453

 26... 1021 9 11500 -- -- 7.6 457 21.0 768

 26... 1025 9 11500 -- -- 7.6 457 21.0 1010

 26... 1030 9 11500 -- -- 7.6 457 21.0 --

 26... 1040 9 11500 50.0 8.9 7.7 455 21.0 --

 28... 0845 9 8380 -- 9.3 7.8 427 20.0 30.0

 28... 0930 9 8380 -- -- 7.7 423 20.0 --

 28... 1015 9 8380 20.0 9.5 7.9 423 20.0 --
Appendix 1 39

03086000 OHIO RIVER AT SEWICKLEY, PA—Continued

WATER-QUALITY DATA, WATER YEAR OCTOBER 2000 TO SEPTEMBER 2001

 SAMPLE FECAL SAMPLE

 LOC- ENTERO- COLI- LOC-

 ATION, E COLI, COCCI, FORM, ATION,

 CROSS TUR- MTEC MF ME MF, MFC MF, CROSS

 MEDIUM SECTION BID- WATER WATER WATER SECTION

 DATE CODE (FT FM ITY (COL/ (COL/ (COL/ (FT FM

 R BK) (NTU) 100 ML) 100 ML) 100 ML) L BANK)

 (72103) (00076) (31633) (31649) (31616) (00009)

 JUL

 12... 9 -- 18 450 120 640 20.0

 12... 9 -- 25 280 45 700 --

 12... 9 20.0 11 260 55 420 --

 18... 9 -- 11 160 140 200 50.0

 18... 9 -- 11 6 5 50 --

 18... 9 35.0 6.8 45 <5 85 --

 24... 9 -- 7.6 300 200 230 50.0

 24... 9 1000 8.9 15 <5 40 --

 24... 9 740.0 10 40 <5 15 --

 24... 9 480.0 13 90 15 120 --

 24... 9 250.0 11 5 <5 15 --

 24... 9 -- 11 <5 10 20 --

 24... 9 50.0 6.7 15 <5 15 --

 31... 9 -- 16 65 35 100 30.0

 31... 9 -- 32 20 <5 120 --

 31... 9 25.0 11 160 60 200 --

 AUG

 07... 9 -- 9.9 75 25 100 65.0

 07... 9 -- 14 40 15 95 --

 07... 9 20.0 10 45 10 100 --

 08... 9 -- 14 200 260 700 65.0

 08... 9 -- 26 1300 350 650 --

 08... 9 20.0 15 760 540 590 --

 09... 9 -- 50 900 595 1600 65.0

 09... 9 -- 23 400 115 580 --

 09... 9 40.0 17 520 25 960 --

 10... 9 -- 10 300 65 870 60.0

 10... 9 -- 15 420 70 250 --

 10... 9 40.0 8.7 260 50 560 --

 14... 9 -- 9.4 460 15 560 40.0

 14... 9 -- 12 460 10 560 --

 14... 9 40.0 6.4 500 20 660 --

 21... 9 -- 5.4 15 5 40 70.0

 21... 9 -- 9.6 10 5 25 --

 21... 9 40.0 5.7 15 5 25 --

 28... 9 -- 12 130 55 420 50.0

 28... 9 1010 -- 110 20 130 --

 28... 9 750.0 -- 490 15 100 --

 28... 9 -- 13 240 10 760 --

 28... 9 480.0 -- 260 5 170 --

 28... 9 250.0 -- 140 5 220 --

 28... 9 20.0 6.9 320 25 160 --

 29... 9 -- 40 100 705 3100 30.0

 29... 9 -- 37 2300 310 2200 --

 29... 9 60.0 26 1400 400 1700 --

 30... 9 -- 19 40 65 890 50.0

 30... 9 -- 24 2300 180 770 --

 30... 9 40.0 21 40 135 8 --

 SEP

 04... 9 -- 11 10 15 120 60.0

 04... 9 -- 14 100 <5 120 --

 04... 9 50.0 9.7 80 5 100 --

 26... 9 -- 10 1900 35 2700 50.0

 26... 9 -- -- 600 15 2600 243

 26... 9 -- -- 440 10 420 453

 26... 9 -- -- 2100 50 4700 768

 26... 9 -- -- 2100 10 3100 1010

 26... 9 -- 13 2000 20 3200 --

 26... 9 50.0 10 2200 30 3600 --

 28... 9 -- 11 120 5 240 30.0

 28... 9 -- 13 140 15 230 --

 28... 9 20.0 12 3100 10 31000 --