JOHNSTOWN-WESTERN PENNSYLVANIA

STORM AND FLOODS OF

JULY 19-20, 1977

Report prepared jointly by the U.S. Geological Survey 

and the National Oceanic and Atmospheric Administration

U.S. DEPARTMENT OF THE INTERIOR U.S. DEPARTMENT OF COMMERCE

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1211
JOHNSTOWN-WESTERN 

PENNSYLVANIA STORM AND FLOODS 

OF JULY 19-20, 1977

By L RAY HOXIT, ROBERT A. MADDOX, CHARLES F. CHAPPELL, 

National Oceanic and Atmospheric Administration, and 

STAN A. BRUA, U.S. Geological Survey

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1211

Report prepared jointly by the U.S. Geological Survey and 

the National Oceanic and Atmospheric Administration

UNITED STATES GOVERNMENT PRINTING OFFICE, W ASH I N GTO N : 1 982
UNITED STATES DEPARTMENT 

OF THE INTERIOR

UNITED STATES DEPARTMENT 

OF COMMERCE

JAMES G. WATT, Secretary MALCOLM BALDRIGE, Secretary

GEOLOGICAL SURVEY NATIONAL OCEANIC AND ATMOSPHERIC 

ADMINISTRATION

Dallas L. Peck, Director John V. Byrne, Administrator

Library of Congress Cataloging in Publication Data

United States. Geological Survey.

Johnstown-western Pennsylvania storm and floods of July 19-20, 1977.

(Geological Survey professional paper ; 1211)

Bibliography: p.

Supt. of Doc. no.: I 19.16:1211

1. Johnstown metropolitan area, Pa.--Storm, 1977. 2. Johnstown metropolitan area, Pa.--Flood, 1977. I. Hoxit, Lee R.

II. United States. National Oceanic and Atmospheric Administration. HI. Title. IV. Series: United States. Geological

Survey. Professional paper ; 1211. 

QC943.5.U6U53 551.48'9'0974877 80-607777

For sale by the Distribution Branch, U.S. Geological Survey, 

604 South Pickett Street, Alexandria, VA 22304
CONTENTS

Glossary _______. 

Abstract _______. 

Introduction _____.

Acknowledgments . Conversion factors. 

The meteorology.

._______ IV

._______ 1

._______ 1

._______ 1

________ 3

________ 3

________ 3

________ 8

.________ 21

Discussion and summary __________________ 28

The floods of July 19-20,1977 _________________ 29

Recurrence intervals ____________________ 29

General meterological conditions _____

Mesoscale analysis _________________

Distribution of rainfall ______________

The floods of July 19-20, 1977-Continued

Determination of peak discharges ___.

Descriptions of the floods _______.

Allegheny River basin _______.

Conemaugh River basin ______.

Susquehanna River basin ________

Potomac River basin ____________

Summary of flood stages and discharges. 

Breached dams ____________________

Historical floods ______________________

Deaths and damages __________________

References _________________.

Page

30

30

30

31

39

39

40

40

43

54

55

ILLUSTRATIONS

Page

FIGURE 1-5. Maps showing:

1. Location of flood area in western Pennsylvania ____________________________ __ 2

2. Surface analyses ___________________________________________________ 4

3. Five-hundred-millibar analyses _____________________________________ ____ 5

4. Stability indices ___________________________________________________ 9

5. Precipitable-water analyses _____________________________________________ 10

6. Plots of Pittsburgh rawinsonde data _________________________________________ __ 11

7. Graph showing vertical profiles of equivalent potential temperature derived from the Pittsburgh rawinsonde data ___ 13

8. Maps showing regional mesoscale analyses, 1400 EDT, July 19, through 0400 EDT, July 20,1977 ___________ 14

9. Geostationary Operational Environmental Satellite (GOES) photographs, 1400 EDT, July 19, through 0400 EDT,

July 20,1977 ___________________________________________________________ 18

10. Maps showing hourly positions of major thunderstorm outflow boundaries ___________________ 22

11. Maps showing hourly rainfall analyses ____________________________________________ 23

12. Graphs showing observed hourly rainfall at three stations within the heavy rainfall area _________________ 27 

13-15. Maps showing:

13. Total rainfall indicated by meteorological radar _____________________________ _ 29

14. Total observed rainfalls _______________________________________________ 30

15. Locations of flood-determination sites in western Pennsylvania _________________________ 32

16. Graph of maximum discharge versus drainage area for flood of July 19-20,1977, and for other known floods ______ 34

17. Photograph showing remains of several homes and a church along Little Paint Creek in Scalp Level ___________ 35

18. Hydrographs of stage and discharge of Stony Creek at Ferndale _____________________________ 36

19. Photograph showing aerial view of breach in Sandy Run Dam _______________________________ 37

20. Hydrographs of stage and discharge of Little Conemaugh River at East Conemaugh ___________________ 38 

21-27. Photographs showing:

21. Flooded business establishments in downtown Johnstown at Park Place _____________________ 39

22. Flooding at Franklin Street United Methodist Church in Johnstown _______________________ 40

23. Flooding at Johnstown's Lee Hospital __________________________________________ 42

24. Stony Creek near the height of the flood ______________________________________ 43

25. Maximum heights of the 1889,1936, and 1977 floods at Johnstown's City Hall __________________ 44

26. Destruction along an unnamed tributary to the Conemaugh River between the Coopersdale and Minersville sections of Johnstown __________________________________________________ 45

27. Laurel Run Dam ___________________________________________________ 46 

28-30. Graphs showing:

28. Hydrographs of stage and discharge of the Conemaugh River at Seward _____________________ 48

29. Flood-crest profile below Laurel Run Dam _____________________________________ 49

30. Flood-crest profile below Sandy Run Dam _________________________________ 50

in
IV CONTENTS

FIGURES 31-34. Photographs showing:

31. Flood damage downstream from the Laurel Run Dam.

32. Eastbound lanes of State Highway 56, near Johnstown's eastern corporate boundary, undermined by floodwaters from Solomon Run ________________________________________________________________

33. Home damaged by flooding from Solomon Run in the Walnut Grove section of Johnstown __________________

34. Flooding in the Hornerstown section of Johnstown ________________________________________________

51

52

53

54

TABLES

TABLE 1. Summary of flood stages and discharges, 

2. Breached dams _____________,

3. Losses in individual severe floods in the United States since July 1902

4. Site descriptions and gage-height and discharge data ____________

5. Floodmark data _____________________________

GLOSSARY

Page 

41 

43 

54 

59 

64

Acre-foot (acre-ft). The quantity of water required to cover 1 acre to a 

depth of 1 foot. It is equal to 43,560 ft3 (cubic feet), 325,851 gal 

(gallons), or 1233 m3 (cubic meters).

Altimeter settling. The pressure required to make an altimeter 

indicate zero altitude at an elevation of 10 ft above mean sea level.

Cirrus anvil. High clouds that spread outward from the tops of 

thunderstorms.

Continuous-record station. A gaging site where a record of the flood 

hydrograph is collected systematically.

Convection. Vertical motions and mixing resulting when the atmosphere becomes thermodynamically unstable.

Crest-stage station. A stream-gaging site where only information on 

crest stage and peak discharge is collected systematically.

Cubic feet per second (ft3/s). A rate of discharge. One cubic foot per 

second is equal to the discharge of a stream of rectangular cross section 1 ft wide and 1 ft deep, flowing at an average velocity of 1 ft per 

second.

Cubic feet per second per square mile. ((ft3/s)/mi2). The average 

number of cubic feet of water per second flowing from each square 

mile of area drained by a stream, with the assumption that the runoff 

is distributed uniformly in time and area.

Current meter. An instrument for measuring the velocity of flowing 

water.

Datum of the gage. The elevation of the "zero" reading of a streamflow-gaging station above the National Geodetic Vertical Datum of 

1929.

Dewpoint (or dewpoint temperature). The temperature to which a 

parcel of air must be cooled at constant pressure and constant watervapor content in order for saturation to occur.

Drainage area of a stream at a specific location. The area, measured 

in a horizontal plane, that is enclosed by a topographic divide. 

Drainage area is given in square miles.

Echoes. In radar terminology, a general term for the appearance on a 

radar indicator of the electromagnetic energy returned from a 

target.

Equivalent potential temperature. The temperature an air parcel 

would have after undergoing the following processes: dry-adiabatic 

expansion until saturated, pseudo-adiabatic expansion until all 

moisture is precipitated out, then dry adiabatic compression to a 

pressure of 1,000 mb (millibars).

Flood-wave routing model. A mathematical model for determining 

the timing and shape of a flood wave at successive points along a 

stream.

Front. Boundary separating two different air masses.

Gage height. The water-surface elevation referred to some arbitrary 

gage datum. Gage height is often used interchangeably with the 

more general term "stage," although gage height is more appropriate 

when used with a reading on a gage.

Gaging station. A particular site on a stream, canal, lake, or reservoir 

where systematic observations of gage height or discharge are obtained.

Hydrograph. A graph showing gage height or stage, discharge, 

velocity, or other property of water with respect to time.

Inversion (temperature inversion). A layer in the atmosphere in 

which the temperature increases with height.

Isobar. A line of equal or constant barometric pressure.

Isotherm. A line of equal or constant temperature.

K Index. A stability index defined as

KI = (Ttso Tgoo) (T Tjfioo+Titso,

where Tgso is the 850-mb temperature, TMSO is the 850-mb dewpoint 

temperature, TSOo is the 500-mb temperature and (T - Td)700 is the 

difference between the 700-mb temperature and 700-mb dewpoint 

temperature.

Lifted index. A stability index based on the difference, in degrees 

Celsius, between the 500-mb environmental temperature and the 

temperature of a parcel of air lifted adiabatically from or near the 

surface to the 500-mb level.

Meso-high ("bubble high"). A small high pressure system with typical 

horizontal dimensions of 50-500 km. The high pressure is produced 

by the cold outflow from thunderstorms and is best defined near the 

Earth's surface.

Mesoscale. A general term used to define the intermediate scales 

of atmospheric motion, such as thunderstorms, squall lines, and hurricanes.

Millibars (mb). A pressure unit, equivalent to 1,000 dyn (dynes) per 

square centimeter, convenient for reporting atmospheric pressure.

Miscellaneous site. A site where data pertaining only to a specific 

hydrologic event are obtained.

National Geodetic Vertical Datum of 1929 (NGVD of 1929). A 

geodetic datum derived from a general adjustment of the first order
CONTENTS

level nets of both the United States and Canada, formerly called "Sea 

Level Datum of 1929" or "Mean Sea Level."

Precipitable water. The total atmospheric water vapor contained in a 

vertical column of unit-cross-sectional area extending from the surface up to a certain pressure level, usually 500 mb.

Radiosonde. A balloon-borne instrument package for measuring and 

transmitting meteorological data.

Rawinsonde. Meteorological data-collection system including a 

radiosonde and reflectors for measuring winds by radar.

Recurrence interval. In this report, the average interval of years 

within which a given flood discharge will be exceeded once.

Runoff. That part of the precipitation that appears in streams. Runoff, 

given in inches, is the depth to which the drainage area would be

covered if the runoff for a given time period were uniformly

distributed over the surface. 

Sounding. A single complete radiosonde observation of the upper

atmosphere. 

Stage-discharge relation. The relation between stage or gage height

and the flow rate of water in a channel. 

Temperature. Expressed in degree Farenheit (°F), Celsius (°C), or

kelvins (K). Relationships between these temperature scales are

listed in the section titled Conversion Factors. 

Time of day. Expressed in 24-hour time. For example, 12:30 a.m. is

0030 hours; 1:00 p.m. is 1300 hours. All time noted is eastern

daylight time (EDT).

Trough. An elongated area of relatively low atmospheric pressure. 

VIP. Video Integrator Processor.

JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF

JULY 19-20, 1977

By L. RAY HOXIT, ROBERT A. MADDOX, and CHARLES F. CHAPPEL, 

National Oceanic and Atmospheric Administration, and STAN A. BRUA, U.S. Geological Survey

ABSTRACT

Dynamics associated with a weak mid-tropospheric short wave triggered widespread thunderstorms across Pennsylvania between the 

afternoon of July 19 and the morning of July 20, 1977. During this 

period, two major squall lines moved across the State. The western 

part of the outflow boundary produced by the second line became 

almost stationary in western Pennslyvania, resulting in 6 to 9 hours of 

nearly continuous thunderstorm activity. More than 6 inches of rain 

fell over a 400-square-mile-area of western Pennsylvania. In the hills 

just north and east of Johnstown, rainfall totals were high as 12 inches.

Flash flooding was severe as the storms moved slowly 

southeastward across the Allegheny, Susquehanna, and Potomac 

River basins. Runoff rates exceeding unit discharges of 1,000 cubic 

feet per second per square mile were determined for eight streams 

with drainage areas as large as 10 square miles. The greatest computed rate for natural conditions was 2,390 cubic feet per second per 

square mile for a site on Sandy Run, about 5 miles east of Johnstown. 

A unit discharge of 3,360 cubic feet per second per square mile was 

computed for a site downstream from Laurel Run Dam-the largest of 

seven earthfill, gravity-type dams that were breached. Floods were 

also severe on larger streams, such as the Conemaugh River at 

Seward, which had a peak discharge of 115,000 cubic feet per second 

from a drainage area of 715 square miles. Recurrence intervals for this 

discharge and for peak discharges at seven other gaging stations are 

estimated to be 100 years or more.

At least 78 deaths were attributed to the floods, and eight persons 

were still listed as missing 1 year later. Total damages in the eightcounty flood area were extremely high and might exceed $330 million.

This report describes the storm and the associated flooding. Included 

are detailed analyses from surface raingages, National Weather Service radar, and synoptic charts. Descriptions of flooding are supported 

by peak stage and discharge data at 30 streamflow-gaging stations and 

27 miscellaneous sites. A brief discussion of the deaths and damages 

resulting from the flood is also presented.

INTRODUCTION

A series of intense thunderstorms formed over 

western Pennsylvania during the evening and early 

morning of July 19-20,1977. These storms, triggered by 

a mesoscale, quasi-stationary thunderstorm outflow 

boundary, produced an elongated northwest-southeast 

pattern of heavy rainfall. Regional topography probably 

played a role in focusing the heaviest rains in the mountains just north and east of Johnstown. In parts of Indiana and Cambria Counties, shown on the map in figure

1, as much as 12 in. of rain fell in 6 to 9 hours, resulting 

in some of the worst flooding ever known in the northeastern United States. Previously known maximum 

flood flows were surpassed at 12 of the 30 streamflowgaging stations in the area. The flash floods that occurred on many small streams were especially severe, 

causing numerous deaths and much structural damage.

The steep terrain of the Johnstown area was a major 

factor contributing to the severity of much of the 

flooding. Undoubtedly, steep channel slopes resulted in 

destructively high velocities. Average stream velocities 

of 10-15 ft/s (feet per second) were common and, in 

some places, exceeded 20 ft/s. Runoff rates were also affected to some extent by both the steep channel slopes 

and hillsides. Many streams that drain areas less than 10 

mi2 (square miles) had peak runoff rates greater than 

1,000 (ft3/s)/mi2 (cubic feet per second per square mile).

Some severe flooding also resulted from the failure of 

seven earthfill, gravity-type dams. The most disastrous 

failure occurred just north of Johnstown on Laurel Run, 

where about 40 persons are known to have lost their 

lives. Much destruction was also reported downstream 

from a breached dam on Sandy Run, several miles east 

of Johnstown. However, the effects of the dam failures 

on the peak-flood level in downtown Johnstown were not 

significant.

Peak stage and discharge data collected at 57 sites are 

compiled in this report to document the flooding. Floodcrest elevations are also provided for reaches of selected 

streams.

One of the most notable aspects of the flooding was 

the great monetary loss incurred over such a small area. 

Estimates of damage indicate the total physical losses 

may be in excess of $330 million in a 1,000-mi2 area 

around Johnstown. The large losses can be attributed 

mostly to extensive industrial and commercial development on the flood plains.

ACKNOWLEDGMENTS

Meteorological data presented herein are mostly 

a condensation of an Environmental Research
JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

Base from U.S. Geological Survey 

1-500,000, State base map, 1977

0 10 30 40 KILOMETERS

PENNSYLVANIA \ 

-FLOOD AREA

FIGURE 1. -Location of flood area in western Pennsylvania.
THE METEOROLOGY

Laboratories Technical Report titled "Meteorological 

Analysis of the Johnstown, Pennsylvania Flash Flood, 

19-20 July 1977" (Hoxit and others, 1978). This 

technical report resulted from a combined effort of the 

Environmental Research Laboratories (ERL), the National Weather Service (NWS), and the National Environmental Satellite Service (NESS).

Most of the hydrologic data were collected by the U.S. 

Geological Survey (USGS) as part of cooperative programs with the Pennsylvania Department of Environmental Resources and the U.S. Army Corps of 

Engineers. Some data collected by the cooperating 

agencies are also included and noted in the report.

The photographs were furnished by the JohnstownTribune Democrat or the Pennsylvania Air National 

Guard, as noted, or were taken by USGS personnel.

Information on flood damage was furnished by the 

Greater Johnstown Chamber of Commerce and the 

Pennsylvania House of Representatives. Casualty 

figures were provided by the American Red Cross.

CONVERSION FACTORS

The meteorological data in this report are presented 

using both the inch-pound units and International 

System (SI) units. Measures are expressed in the type of 

units most commonly used for the given application. The 

hydrological data uses inch-pound units entirely. Factors are provided in the following table for converting 

inch-pound to SI units. Inch-pound units may be converted from SI units by "dividing" the number of SI 

units by the factor listed in the table:

Multiply inch-pound units

inch (in.)

foot (ft) 

mile (mi) 

nautical mile (nmi)

square mile (mi2) 

acre

cubic foot (ft3)

million gallons (106 gal) 

acre-foot (acre-ft)

cubic foot per second (ft3/s)

cubic foot per second per square 

square mile [ft3/s)/mi2]

foot per second (ft/s) 

knot (kn)

millibar (mb)

Length

25.4

2.54

0.3048

1.609

1.852

Area

2.590

4047

0.4047

Volume

28.32

0.02832

3785

1233

Flow

28.32

28.32

0.02832

0.01093

Velocity

0.3048

1.852

Pressure

0.1

To obtain SI units

millimeter (mm) 

centimeter (cm) 

meter (m) 

kilometer (km) 

kilometer (km)

square kilometer (km2) 

square meter (m2) 

square hectometer (hm2)

cubic decimeter (dm3) 

cubic meter (m3) 

cubic meter (m3) 

cubic meter (m3)

liter per second (1/s) 

cubic decimeter per second

(dm3/s)

cubic meter per second (m3/s) 

cubic meter per second per

square kilometer [(ms/s)/km2 |

meter per second (mis) 

kilometer per hour (km/h)

kilopascal (kPa)

Temperature data are expressed in degrees 

Fahrenheit (°F), degrees Celsius (°C), or kelvins (K). 

Following are several expressions that can be used to 

convert the data from one of these scales to another:

°F = 9/5 °C + 32.0; °C = 5/9 (°F-32.0) or °C = K-273.16

Eastern daylight time (EDT) is used throughout this 

report. Greenwich Meridian Time, commonly used for 

meterological analyses, may be obtained by adding 4 

hours to the times shown.

Elevations used in this report are referred to National 

Geodetic Vertical Datum (NGVD) of 1929, unless otherwise qualified. At gaging-station sites, elevations of the 

water surface may be obtained by adding the gage 

height to the datum of the gage given in table 4.

THE METEOROLOGY 

GENERAL METEOROLOGICAL CONDITIONS

The evolution of larger-scale processes beginning at 

0800 EDT on July 19 and extending through 0800 EDT 

on July 20, before and during the intense rainfall over 

southwest Pennsylvania, is shown in figures 2 and 3. 

These standard meteorological analyses provide a 

general setting and background for the detailed mesoscale analyses presented in the next section.

Most of the eastern United States was under general 

anticyclonic flow around a large subtropical high in the 

western Atlantic-a fairly typical midsummer pattern. 

The major storm track was across central Canada, and 

associated frontal systems lay across east-central 

Canada southwestward into the northern High Plains of 

the United States. Early on July 19, a weak surface 

trough, associated with an upper-level low pressure 

area, extended northeastward through Louisiana and 

Mississippi. This low pressure area moved slowly northwestward to the Arkansas region by 0800 EDT on July 

20. A small, separate high-pressure area persisted during this period along the western slopes of the Appalachian Mountains in West Virginia and eastern Kentucky. Dewpoint temperatures of 70 °F or greater extended northward into the Great Lakes region and into 

a small part of southeastern Canada. Low-level moisture 

flux into the Pennsylvania region was from the 

southwest.

Major thunderstorm outflow boundaries were generated in the Lake Erie region and moved southeastward across the mid-Atlantic States. A mesoscale high 

pressure system ("bubble high") was evident at both 

2000 EDT on July 19 and 0800 EDT on July 20.

The flow pattern in the middle troposphere (500 mb) 

was again fairly typical for midsummer (fig. 3A-C). At 

0800 EDT on July 19, a broad, large-scale ridge existed 

over the central and eastern United States. A weak
JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

08 06 04

A 0800 EOT, JULY 19, 1977

B 2000 EOT, JULY 19, 1977

 16 

C 0800 EOT, JULY 20, 1977

EXPLANATION

Area where dewpoint temperatures exceed 

70 degrees Fahrenheit

Line of equal atmospheric pressure at sea 

level. -16 = 1016 millibars. Interval 2 

millibars

Trough line

Cold Front-dashed where dissipating

Warm Front-dashed where dissipating

Front-dashed where

H 

L

Stationary 

dissipating

Geographic center of high-Pressure 

System

Geographic center of low-pressure system

 . -, Thunderstorm outflow boundary. Frontal 

symbols indicate whether cool 

thunderstorm air or warmer 

environmental air is advancing

FIGURE 2.-Surface analyses at indicated times. A, 0800 EDT, 

July 19, 1977. B, 2000 EDT, July 19, 1977. C,0800 EDT, July 

20, 1977. Frontal positions, outflow boundaries, pressure 

centers, and isobars for 2-mb intervals (numbers represent the 

last two digits of pressure in millibars, 16 = 1,016 mb) are shown 

in black. Frontal symbols are added to conventional squall line 

notations to indicate whether cool thunderstorm, outflow, or 

warmer environmental air is advancing. Regions having dew 

points >70° are shaded in red.
THE METEOROLOGY

A 0800 EDT, JULY 19, 1977

FIGURE 3.-Five-hundred-millibar analyses at indicated times. A, 0800 EDT, July 19, 1977. B, 2000 EDT, July 19, 1977. C, 0800 EDT, 

July 20, 1977. (Figure 3A is shown above. Figures SB, 3C, 3D are on following pages.)

closed low pressure area over the southern Mississippi 

Valley and a short-wave trough (meso-a scale) over the 

eastern Greak Lakes region constituted small pertubations in this mean pattern. A moderately strong westerly current extended across southern Canada.

The short-wave over the Lake Huron and Lake Erie 

region at 0800 EDT on July 19 played a key role in the 

formation of the flash-flood-producing thunderstorms. 

This system moved east-southeast at 15-20 knots across

Pennsylvania during the next 24 hours. The wave axis 

remained tilted (from northeast to southwest) throughout this period. Strong, warm advection in the lower 

troposphere was indicated to the west and northwest of 

the short-wave trough. As warmer air moved under the 

relatively cool air aloft, the atmosphere became more 

unstable. This flow regime was somewhat uncharacteristic, as low-level warm advection typically occurs in 

advance (east) of short-wave troughs embedded in
JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

C5

\ \

582

B 2000 EDT, JULY 19, 1977

FIGURE 3.-Continued.
THE METEOROLOGY

C 0800 EOT, JULY 20, 1977

EXPLANATION 

Area where dewpoint temperature was within 6-degrees Celsius of air temperature

Contour showing altitude of 500-millibar surface. 582 = 5820 meters. Contour interval 30 

meters. Datum is mean sea level

Line of equal air temperature. Interval 2 degrees Celsius 

Axis of Pressure Trough

Geographic enter of highest altitude of 500-millibar surface 

Geographic center of lowest altitude of 500-millibar surface

OBSERVATION STATION. Upper left number is air temperature, in degrees Celsius. Lower 

left number is depression of dewpoint temperature, in degrees Celsius; X shown when 

depression greater than 30 degrees Celsius. Upper right number is altitude of 500-millibar 

surface, in meters; 581 =5810 meters. Shaft indicates wind direction. Barbs on shaft indicate 

wind speed, in knots. Long barb-10 knots; short barb = 5 knots; Flag = 50 knots; M indicates missing data

FIGURE 3.-Continued.
8 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

westerly flow. At the same time, the upward vertical 

motion in advance of the trough axis acted to destabilize 

the atmosphere further and to trigger widespread convection during the afternoon and evening of July 19.

Analyses of stability indices computed from standard 

rawinsonde data (fig. 4) shows the development of a 

very unstable air mass ahead of the advancing shortwave trough. By 2000 EDT on July 19, the air mass over 

eastern Pennsylvania was characterized by Lifted Index 

values of - 4 or less and K Index values of > 36. These 

values are comparable with those associated with outbreaks of severe thunderstorms.

Precipitable water in the surface to 500-mb layer was 

substantially greater than climatological mean values 

along and ahead of the upper-level trough axis (fig. 5). 

High precipitable-water values propogated southeastward and increased in areal coverage during July 19. 

Values greater than 4.4 cm were found over a wide area 

extending from northeastern Kentucky through much of 

New York by 2000 EDT on July 19. The 4.6 cm 

measured at Pittsburgh at 2000 EDT was approximately 

172 percent of the July average documented by Lott 

(1976).

Data from three upper air soundings taken at Pittsburgh during this 24-hour period are shown in figure 6. 

Note that the winds shifted in the 850-400-mb layer 

from west-southwest to northwest and north as the 

short-wave trough passed. Abundant moisture up to 

almost 500 mb was evident in the 2000 EDT sounding 

(fig. 6B). The surface inversion evident in the temperature and moisture profiles at 2000 EDT resulted 

from earlier thunderstorms and was topped by strong, 

westerly winds immediately above. Strongest winds 

were in the 700-950-mb layer, and weak wind shear was 

present from the top of the inversion to nearly 300 mb.

Profiles of equivalent potential temperature at Pittsburgh (fig. 7) further show the unstable environment 

over western Pennsylvania. Equivalent potential temperatures of more than 360 K are characteristic of 

tropical boundary layer. The 2000 EDT sounding indicated a value of 362 K at the top of the surface inversion.

A conditionally unstable atmosphere, uncommonly 

high moisture content, and the slow moving short-wave 

trough all contributed to thunderstorm development 

over a rather large area on the afternoon and evening of 

July 19, 1977. This area included most of Pennsylvania 

and parts of several surrounding States. However, the 

atmospheric structure over this region differed in the 

following ways from that generally associated with a

major tornado outbreak: (1) Moisture content was 

relatively high up to nearly 500 mb, which contrasts 

with the strong inversion and dry air above, often 

observed between 700 and 850 mb in the pre-tornado environment, and (2) wind shear was small in the convective cloud layer (from cloud base to nearly 300 mb). The 

precipitation efficiency of convective clouds in this environment is greater than for clouds embedded in the 

highly sheared environment commonly associated with 

tornadoes, strong surface winds, and large hail 

(Mauritz, 1972); that is, a greater percentage of the 

water vapor condensed in the updrafts eventually 

reaches the ground as precipitation.

However, two important questions cannot be 

answered by the synoptic scale analyses just presented: 

(1) Why did the convective processes focus on a relatively small area around Johnstown, and (2) What distinguished this region from the surrounding region, which 

apparently had the same general potential for heavy 

thunderstorms? The answers to these questions may lie 

in the evolution of mesoscale weather processes 

preceding and during the storm.

MESOSCALE ANALYSIS

Surface and radar charts at 2-hour intervals for the 

period 1400 EDT, July 19, to 0400 EDT, July 20, are 

shown in figure 8. Analyses of the pressure fields 

(altimeter settings) and the major thunderstorm outflow 

boundaries were based on surface observations (both 

hourly and special), radar data, and satellite photographs. Small systematic errors in the altimeter settings 

were suspected at several stations (for example, Bradford, Pa., and Binghamton, N.Y.). However, no corrections were made, so that analyses would be based as 

closely as possible on information available under operational conditions.

Radar analyses are composites prepared from radarscope photographs taken at National Weather Service 

WSR-57 radar sites at Pittsburgh, Pa., Buffalo, N.Y., 

New York City, N.Y., Atlantic City, N.J., and Patuxent, 

Md. A small region of central Pennsylvania and southern New York was not covered by any of the 125-nmirange scopes.

Geostationary Operational Environmental Satellite 

(GOES) imagery for the same general time period is 

shown in figure 9. Routine maintenance procedures 

were underway during the period 0030 to 0330 EDT on 

July 20, and satellite imagery was not available. Visible 

imagery is shown through 1800 EDT, July 19; the
THE METEOROLOGY

A 0800 EDT, JULY 19, 1977 C 0800 EDT, JULY 20, 1977

FIGURE 4.-Stability indices at indicated times. Regions having 

K-Index values >36 are shaded. A, 0800 EDT, July 19, 1977. B, 

2000 EDT, July 19, 1977. C, 0800 EDT, July 20, 1977.

B 2000 EDT, JULY 19, 1977
10 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

A 0800 EOT, JULY 19,1977

~l

C 0800 EOT, JULY 20, 1977

FIGURE 5. - Precipitable water analyses (surface to 500 mb) in centimeters for indicated times. Regions having more than 4.4 cm 

are shaded. A, 0800 EDT, July 19, 1977. B, 2000 EDT, July 19, 

1977. C, 0800 EDT, July 20, 1977.

B 2000 EDT, JULY 19, 1977
THE METEOROLOGY 11

A 0800 EST, JULY 19,1977

 K Index = 39 Lifted Index = -6 8

- Precipitable Water (surface to 500 mb) = 4.6 cm j

A. VX \

B 2000 EST, JULY 19, 1977 

EXPLANATION

 Dewpoint temperature (left profile)

 Air temperature (right profile)

10 Moist-adiabat scale, in degrees Celsius

 303.3 Dry-adiabat scale, in degrees Kelvin

f

r

V X)

s,

 0 Air temperature scale, in degrees Celsius

,-, Wind Direction and speed observation. Shaft indicates 

/" wind direction; north is at top. Barbs on shaft indicate

wind speed, in knots; long barb = 10 knots; short barb = 5

knots

FIGURE 6. -Plots of Pittsburgh rawinsonde data at indicated times. A, 0800 

EDT, July 1977. B, 2000 EDT, July 19, 1977. C, 0800 EDT, July 20, 1977. 

Temperature profile in degrees Celsius is shown by solid lines. Red lines show 

plotted wind and dew point temperatures.
12 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

C 0800 EST, JULY 20, 1977

FIGURE 6.-Continued.

remainder of the satellite data are enhanced infrared imagery.

By early afternoon (1400 EDT, July 19), convective activity was already organized and widespread over northwestern Pennsylvania and southern New York (figs. 8A 

and 9A). Thunderstorms along the southern shore of 

Lake Erie in the morning (fig. 2A) had spread eastsoutheastward and expanded into a squall line extending 

from just north of Johnstown into south-central New 

York. In Johnstown, however, only a few hundreths of 

an inch of precipitation was recorded as this line moved 

through the area.

The cool outflow attending the first squall line extended in two arcs from near Lake Ontario southwestward to a meso-low pressure center over north-central 

Pennsylvania, then southwestward to near Johnstown 

before curving northwestward to near Youngstown, 

Ohio. An elongated meso-high, or "bubble"-high, 

pressure area was north of the outflow boundary, while 

an area of light precipitation was forming in extreme 

northwestern Pennsylvania, southwestern New York, 

and northeastern Ohio.

During the afternoon, this first line of convective 

storms and their associated cool outflow boundary continued to move eastward at 30-40 kn (fig. 10A). By 2000 

EDT, the leading edge of cooler air extended from 

southwestern Vermont through extreme southeastern 

New York to the eastern Pennsylvania border. The 

southwestern part of the outflow boundary moved back 

toward the northeast and assumed the characteristic of 

a shallow mesoscale warm front.

At about 1600 EDT, an isolated thunderstorm formed 

just west of Pittsburgh. This storm moved eastsoutheastward at about 50 kn, affecting the Pittsburgh 

region from 1700 to 1800 EDT and dropping about half 

an inch of precipitation on Johnstown between 1800 and 

1900 EDT. At 2000 EDT, the small meso-high produced 

by this storm had reached the area near Johnstown, and 

the storm was dissipating.

Meanwhile, clouds and precipitation over northwestern Pennsylvania had moved slowly southeastward 

and organized into a second major squall line. Several 

strong cells were indicated by Pittsburgh radar (fig. 8C, 

D), and the late afternoon satellite imagery indicated 

several overshooting tops embedded in the line (fig. 9C). 

By 2000 EDT, this activity had progressed into the 

northern parts of the Conemaugh River basin.

The behavior of the second squall line differed from 

the first in several ways. It propagated toward the 

southeast (instead of east) and at a slower speed than 

the first line. More importantly, the western section of 

the outflow boundary was nearly stationary along the 

Ohio-Pennsylvania border. The quasi-stationary character of this outflow boundary northeast of Pittsburgh 

continued during the remaining hourly analyses (figs. 

8E-H).

By 2200 EDT, the first series of intense thunderstorms had moved across the Johnstown region (fig. 

8E). A well-defined meso-high attending these storms 

was located slightly northwest of Johnstown, while the 

associated outflow boundary (second of the series) was 

oriented along the southern Pennsylvania border, northwestward to just east of Pittsburgh and Youngstown, 

Ohio. This boundary, produced by the cool downdrafts 

from the thunderstorms, remained quasi-stationary and 

nearly perpendicular to the low-level flow of moist air
THE METEOROLOGY 13

0800 EST JULY 19 

2000 EST JULY 19 

0800 EST JULY 20

330 335 340 345 350

EQUIVALENT POTENTIAL TEMPERATURES, IN KELVIN 

FIGURE 7.-Vertical profiles of equivalent potential temperatures in Kelvin, derived from the Pittsburgh rawinsonde data.

streaming into western Pennsylvania from Ohio. By 

0000 EDT, July 20, a mesoscale "wake" low had formed 

in east-central Pennsylvania (fig. &F).

The two-hourly analyses and satellite photos, along 

with the summary analyses presented in figure 10B, illustrates the quasi-stationary and concentrated nature 

of the Johnstown flood-producing storms. As the warm, 

unstable air from the west was lifted over the cool 

outflow boundary, new thunderstorms were triggered. 

Once these storms formed, they moved with the mean

midtropospheric flow southeastward over the Conemaugh River basin.

Maddox and others (1979) and Mogil and Groper 

(1976) have found that quasi-stationary thunderstorm 

outflow boundaries contribute to many flash floods. 

These boundaries, as in the Johnstown instance, focus 

the thunderstorm development and resulting heavy 

rains over relatively small regions. The part of these 

boundaries most likely to become stationary is that part 

parallel to the midtropospheric winds.

(Text continued on page 21.)
14 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

___ 30.25 30.22 30.16 30.13

A 1400 EDT. JULY 19, 1977

 30.10 

EXPLANATION

Area covered by radar 

echoes. Light shading = video intergrator 

processor (VIP) Level 1 or 

greater; dark shading = VIP Level 3 or greater

Line of equal altimeter setting, in inches of mercury, 

interval 0.03 inch

Thunderstorm outflow 

boundary. Frontal symbols indicate direction the 

boundary is moving

Geographic center of highpressure system

Geographic center of lowpressure system

72 / TE Observing station upper left 

number is air temperature 

in degrees Fahrenheit. 

Lower left number is 

dewpoint temperature in 

degrees Fahrenheit. 

Upper right number is altimeter setting in inches 

of mercury. Middle left 

symbols indicate current 

weather conditions using 

standard meteorological 

surface weather code. 

Lower right often contains additional abbreviated comments 

about current weather

30.05

B 1600 EDT, JULY 19, 1977

FIGURE 8. - Regional mesoscale analyses for indicated times. A, 1400 EDT, July 19, 1977. B, 1600 

EDT, July 19, 1977. C, 1800 EDT, July 19, 1977. D, 2000 EDT, July 19, 1977. E, 2200 EDT, 

July 19, 1977. F, 0000 EDT, July 20, 1977. G, 0200 EDT, July 20, 1977. H, 0400 EDT, July 

20, 1977. Outflow boundaries, pressure centers, pressure troughs, and pressure analysis 

(altimeter settings in intervals of 0.03 in.) are in black. Areas of shading indicate area covered 

by radio echoes (light shading, VIP level 1 or greater, and dark shadings, VIP level 3 or 

greater).
THE METEOROLOGY 15

C 1800 EOT, JULY 19, 1977

D 2000 EOT, JULY 19, 1977

FIGURE 8.-Continued.
16 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

E 2200 EOT, JULY 19, 1977

F 0000 EOT, JULY 20, 1977

FIGURE 8.-Continued.
THE METEOROLOGY 17

G 0200 EOT, JULY 20, 1977

H 0400 EOT, JULY 20, 1977

FIGURE 8.-Continued.
18 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

FIGURE 9.-Geostationary Operational Environmental Satellite (GOES) photographs for indicated times. Visible 

imagery 1400-1800 EDT, July 19 (1-km resolution at satellite subpoint). Enhanced infrared imagery 2000 

EDT July 19 to 0400 EDT July 20 (2-km equivalent resolution at satellite subpoint). A, 1400 EDT, July 19, 

1977. B, 1600 EDT, July 19,1977. C, 1800 EDT, July 19,1977. D, 2000 EDT, July 19,1977. E, 2200 EDT, July 

19, 1977. F, 0000 EDT, July 20, 1977. G, 0400 EDT, July 20, 1977.
THE METEOROLOGY 19

FIGURE 9.-Continued.
20 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

FIGURE 9.-Continued.
THE METEOROLOGY 21

FIGURE 9.-Continued.

The thunderstorm cells moved roughly parallel to the 

outflow boundary and nearly perpendicular to the 

western slopes of the Allegheny Mountains. Orographic 

lift probably enhanced storm intensities and helped concentrate the heavy rain in the hills north and east of 

Johnstown. However, orography was probably not as 

important in triggering these thunderstorms as it was in 

causing the Big Thompson and Rapid City floods (Maddox and others, 1978).

Radar indicated that 12 separate thunderstorm cells 

moved over the Johnstown area between 2000 EDT, July 19, and 0500 EDT, July 20 (Greene and Saffle, 1978). 

The downdrafts and cool outflow from each successive 

cell reinforced and helped maintain the thermal and 

wind discontinuities along the outflow boundary.

As the short-wave trough moved to the east of 

Johnstown, drier, subsiding midtropospheric air moved

into the region. Convective activity was suppressed, and 

the meso-high moved toward the southeast and slowly 

dissipated. Shortly after 0500 EDT, the heavy rain in 

Johnstown ended abruptly.

DISTRIBUTION OF RAINFALL

Temporal and spatial distributions of the rainfall over 

western Pennsylvania before and during the major 

flooding are now examined. Hourly and daily rainfall 

totals from the rain-gage network are shown, as well as 

rainfall estimates from the National Weather Service 

Digitized Radar Experiment (D/RADEX) radar facility 

at Pittsburgh (Greene and Saffle, 1978). D/RADEX 

values were computed and available during the storm. 

Many surface observations of rainfall were not available 

until after the flood.

(Text continued on p. 28.)
22 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

FIGURE 10.- Hourly positions'of major thunderstorm outflow boundaries. A, First major boundary: 1400 EOT, July 19, 1977, to 2000 EDT, July 19, 1977. B, Second major boundary: 1600 

EDT, July 19, 1977, to 0500 EDT, July 20, 1977; red shading defines region where 24-hr rainfalls exceeded 2 in.
THE METEOROLOGY 23

A 1400 1500 EOT, JULY 19,1977 C 1600 1700 EOT, JULY 19,1977

B 1500 1600 EOT, JULY 19,1977 D 1700 1800 EOT, JULY 19, 1977

FIGURE 11. -Hourly rainfall analyses (in inches) for indicated times. Plotted data are observed rainfalls. Analysesishow'D/RADEX rainfall accumulations. A, 1400-1500 EOT, July 19, 1977. B, 1500-1600 EOT, July 19,1977. C, 1600-1700 EOT, July 19,1977. D, 1700-1800 EOT, 

July 19, 1977. E, 1800-1900 EOT, July 19, 1977. F, 1900-2000 EOT, July 19, 1977. G, 2000-2100 EOT, July 19, 1977. H, 2100-2200 

EOT, July 19,1977. 1, 2200-2300 EOT, July 19,1977. J, 2300-2400 EOT, July 19,1977. K, 0000-0100 EDT, July 20, 1977. L, 0100-0200 

EOT, July 20, 1977. M, 0200-0300 EDT, July 20, 1977. N, 0300-0400. EDT, July 20, 1977. 0, 0400-0500 EDT, July 20, 1977. P, 

0500-0600 EDT, July 20, 1977.
24 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

£ 1800 1900 EOT, JULY 19, 1977

0.0 ..

,! P!T 4-01 0.0 - ' f

\ / I 0.01 '

G 2000 2100 EOT, JULY 19,1977

/: 1900 2000 EOT, JULY 19, 1977 H 2100 2200 EOT, JULY 19, 1977

FIGURE 11.-Continued.
THE METEOROLOGY 25

/ 2200 2300 EOT, JULY 19, 1977

T.OO

/.-j Q.O \0.0 °- 12 2.76 

_' I + rl n 0 n

K 0000 0100 EOT, JULY 20,1977

J 2300 2400 EOT, JULY 19, 1977 L 0100 0200 EOT, JULY 20, 1977

FIGURE 11.-Continued
26 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

M 0200 0300 EOT, JULY 20, 1977 O 0400 0500 EOT, JULY 20, 1977

N 0300 0400 EOT, JULY 20, 1977 p 0500 0600 EOT, JULY 20, 1977

FIGURE 11.-Continued
LLI

2.0 

1.8

1.4

14

CJ

? 1.2

Z

 1.0

LL 

Z .6

CC .4 

.2

10

A

16

12

THE METEOROLOGY 

TIME (GMT)

27

18

-July 19 

20 22 00 02 04 06

-July 20- 

08 10 12 14

14 16 18 20 22 00

TIME (EOT) 

TIME (GMT)

02 04 06 08 10

3.0

2.8 

2.6

2.4

2.2

ffi2.0

X 

£ 1.8

^ 1.6

_r 1.4

2 1-2

Z

< 1.0

cc

.8 

.6 

.4 

.2 

0

4 16 18

1

_

-

-

-

-

1 1

0 12 14

B

20 22 00 02

[ I

I I

16 18 20 22

04 06 08 10 12 1'

1 1 1

-

-

-

_-

-

 II 1 1

00 02 04 06 08 1

TIME (EDT)

FIGURE 12.-Observed hourly rainfall at three stations within the heavy rainfall area. A, Public Safety Building,

Johnstown, Pa. B, Strongstown, Pa. C, Dunlo, Pa.
28 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

TIME (GMT)

1

2.8

2.6 

2.4

2.2

[22.0 

U 1.8 

z 1.6

_r 1.4

< U_ 19I -2

< 1.0

DC

.8

.6 

.4 

.2

0

4 16 18 20 22 00 02

' - I I I I

_

-

-

I I I I

0 12 14 16 18 20 22

04 06 08 10 12 1

I I

"

-

_

-

_

 I I I

00 02 04 06 08 H

C TIME (EDT)

FIGURE 12.-Continued.

Analyses of the hourly rainfalls, obtained from 

D/RADEX for the period 1400 EDT, July 19, until 0600 

EDT, July 20, are presented in figure 11. Hourly rainfalls observed at stations in and surrounding the Conemaugh River basin are plotted for the period 1800 to 

0600 EDT.

During the afternoon, the hourly D/RADEX totals 

clearly show the eastward movement of the first squall 

line out of western Pennsylvania and the development 

and eastward extension of the second line over northwestern Pennsylvania.

As the second line moved into the Johnstown area during the late afternoon and early evening, spatial agreement between the hourly rainfall, estimated by radar, 

and observed amounts is reasonably good. Hourly rainfall totals at three stations (fig. 12) indicate that the bulk 

of the rain fell in 6-9 hours.

A comparison of 24-hour rainfall amounts from 

D/RADEX data with an isohyetal analysis of surface 

rain-gage data is shown in figures 13 and 14. The pattern of heavy rainfall is similar in both analyses. 

However, observed maximum totals are more than 12 

in., whereas the maximum radar-determined accumulation is slightly more than 8 in. Figures 11 and 12 suggest 

that radar estimates were somewhat low during the

early evening but compare more favorably with the 

observed values in the 0100 to 0600 EDT, July 20, time 

period.

Analyses presented in figures 12 and 14 show the intensity of the rain during the 6-9-hour period and the 

localized nature of the rainfall. For example, Nanty Glo, 

about 10 miles north of Johnstown, received approximately 12 inches of rain during the 24-hour period, 

whereas locations 30 miles to the southwest received 

little or none.

DISCUSSION AND SUMMARY

The July 19-20, 1977, flash floods in southwest Pennsylvania resulted when large-scale and mesoscale processes combined to focus excessive convective rains over 

a relatively small area. Circulation patterns associated 

with the large surface high off the Atlantic coast and the 

long-wave upper-tropospheric ridge over the eastern 

United States provided a conditionally unstable atmosphere having abundant moisture over a large area of 

the Ohio Valley and central Appalachian Mountain 

region. Dynamic processes associated with a slowly 

moving short-wave trough destabilized the atmosphere 

and acted to trigger and maintain organized convention 

during the morning and afternoon of July 19.
THE FLOODS OF JULY 19-20,1977 29

FIGURE 13.-Total rainfall (in inches) indicated by meteorological radar (D/RADEX). Time period 0800 EDT, July 19, 

to 0800 EDT, July 20, 1977.

In response to the convective activity during the afternoon and early evening, mesoscale pressure systems 

and low-level baroclinic zones were generated. In 

western Pennsylvania, the boundary separating the 

rain-cooled air generated by previous thunderstorms 

became quasi-stationary nearly perpendicular to the 

warm, moist, low-level flow streaming in from Ohio. As 

this unstable air ascended over the rain-cooled air, new 

thunderstorms were triggered, which then moved 

southeastward parallel to the outflow boundary. Each 

thunderstorm cell reinforced the temperature gradient 

along the outflow boundary and maintained the triggering mechanism in a quasi-stationary position. The 

storms moved upslope into the western parts of the Appalachian mountains, releasing maximum rainfall in the 

hills north and east of Johnstown. This process continued for several hours, subjecting the region to a 

series of storms.

The quasi-stationary nature of the storm was eventually terminated as the short-wave trough moved into 

eastern Pennsylvania. Advection of somewhat drier 

midtropospheric air and development of weak subsidence with the trough passage over western Pennsylvania eventually suppressed formation of new cells.

The meteorological conditions leading to the floodproducing rains around Johnstown were those present 

during most significant flash floods (Maddox and others, 

1979). These storms commonly have several important 

characteristics: (1) very moist and conditionally unstable 

conditions, with precipitable water substantially above

normal from the surface to 500 mb; (2) a weak shortwave trough (meso-o! scale) moving through a largescale ridge that provides lifting and air mass destabilization; (3) weak wind shear through much of the cloud 

layer, which contributes to high precipitation efficiencies; (4) topographic features, frontal boundaries, or cool 

outflow boundaries produced by earlier or existing convection, which trigger additional storms and focus heavy 

rain over a relatively small ,area; (5) several cells that 

typically move over the same area, and (6) the tendency 

for rainfall that produces flashfloods to occur at night.

THE FLOODS OF JULY 19-20, 1977

To document the extreme floods in western Pennsylvania on July 19-20, 1977, stream-stage and 

discharge data were collected at 57 sites in the 

Allegheny, Susquehanna, and Potomac River basins. 

Thirty of these sites are at gaging stations, where both 

stage and discharge data are available, and the remainder are miscellaneous sites, for which only peak 

discharges are available. Numbers have been assigned 

to these sites for locating them on a map (fig. 15) and 

referencing flood data. Floodmark data consisting of 

peak-flood elevations throughout selected reaches of 27 

streams in the Mahoning Creek and Conemaugh River 

basins are also presented. Descriptions of the tables containing these data are provided in the section Summary 

of Flood Stages and Discharges.

RECURRENCE INTERVALS

Recurrence intervals were computed at all gaging stations for which at least 10 successive years of peakflow 

data were available; they provide an indication of the 

severity of flooding on the respective streams. The 

recurrence interval, as applied to flooding, is the 

average interval of years within which a given peak 

discharge will be exceeded once. It is inversely related to 

the chance of the given discharge being exceeded in any 

year. For example, a flood having a recurrence interval 

of 50 years, would have one chance in 50 (2 percent 

chance, or 0.02 probability) of being exceeded in any 

year. The occurrence of floods is erratic; a flood of a 

given magnitude may occur in any year, it may occur in 

successive years, or it may not occur within a period 

much greater than the designated interval. Recurrence 

intervals were computed using a log-Pearson type III 

distribution, a regionalized skew coefficient, and other 

guidelines of the U.S. Water Resources Council (1977).
30 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977 

DETERMINATION OF PEAK DISCHARGES

At 34 sites (27 miscellaneous sites and 7 gaging stations), peak discharges for the July 1977 flood were 

determined by indirect methods. These methods are 

based on principles that relate streamflow to observed 

water-surf ace elevations and to the hydraulic properties 

of a stream or a structure that crosses the stream. They 

include the (1) slope-area, (2) contracted-opening, (3) 

flow-over-dam, and (4) flow-through-culvert methods described in Dalrymple and Benson (1967), Matthai (1967), 

Hulsing (1967), and Bodhaine (1968), respectively. Peak 

discharges for the remaining gaged sites were determined from previously established stage-discharge relationships.

DESCRIPTIONS OF THE FLOODS

ALLEGHENY RIVER BASIN

Flooding was severe in much of a 70-mile long by 

25-mile wide area along the Allegheny River basin's 

eastern divide. Allegheny River tributaries affected include Redbank, Mahoning, and Crooked Creeks. The 

Conemaugh River, a tributary to the Kiskiminetas River 

in the southeast part of the basin, had the worst flood.

The main stems of the Allegheny and Kiskiminetas 

Rivers were not flooded owing to flood-control reservoirs near the mouths of Mahoning and Crooked Creeks 

and the Conemaugh River. More than 200,000 acre-feet 

of runoff from this storm was stored in these three 

reservoirs.

Flooding was moderate in the Redbank Creek basin. 

At the gaging station on Big Run near Sprankle Mills 

(site 1), the peak discharge from a drainage area of 7.38 

mi2 was 960 ft3/s. Although this discharge is the highest 

since record collection began in 1963, its recurrence interval is estimated at only 15 years. The peak flow for 

the main stem of Redbank Creek at St. Charles (site 2) 

was 19,000 ft3/s. A recurrence interval of 5 years was 

estimated for this discharge.

Flooding was extreme in the upper half of the Mahoning Creek basin, where as much as 6 inches of rainfall 

was recorded. Stump Creek, at the town of Big Run (site 

3) had a peak flow of 5,240 ft3/s from a drainage area of 

26.8 mi2 , which corresponds to a unit discharge of 196 

(ft3/s)/mi2 . On the main stem of Mahoning Creek at 

Punxsutawney (site 4), the peak flow was 12,700 ft3/s, 

the second highest flow since at least 1936. This is considerably less than the record discharge of 17,300 ft3/s 

during a flood in June 1972, but a change in the carrying 

capacity of the stream resulted in a peak stage for the

FIGURE 14.-Total observed rainfalls (in inches) from 0800 

EDT, July 19, to 0800 EDT, July 20, 1977. A, Western 

Pennsylvania. B, Conemaugh River basin.

July 1977 flood that was 0.3 ft higher than the previous 

record. A recurrence interval of 40 years is estimated 

for the July 1977 peak discharge at this site. The peak 

flow of 5,770 ft3/s on Little Mahoning Creek at McCormick (site 5) was also the second highest for its period of 

record, which extends back to 1939. However, it is only 

7 percent less than the previously known maximum discharge of 6,200 ft3/s, in June 1972. The July 1977 peak 

discharge at this site is estimated to have a recurrence 

interval of 20 years.

Downstream from Little Mahoning Creek, the peak 

flow of Mahoning Creek was greatly reduced by the effects of Mahoning Creek Lake. About 28,500 acre-feet 

of flood-control storage was utilized to reduce the peak 

flow below Mahoning Creek Dam (site 6) to 6,560 ft3/s on 

July 22.

Flooding was significant throughout the Crooked 

Creek basin. At Shelocta (site 7), in the central part of 

the basin, the peak discharge on Crooked Creek was 

estimated to be 9,940 ft3/s, or 85 (ft3/s)/mi2 from a 

drainage area of 117 mi2 . Farther downstream at Idaho 

(site 8), the peak flow on Crooked Creek was 8,860 ft3/s, 

a unit discharge of 46 (ft3/s)/mi2 from a drainage area of 

191 mi2 . The recurrence interval for this peak is 

estimated at 10 years. A recurrence interval of about a 

year is estimated for the peak discharge of 4,150 ft3/s 

downstream from Crooked Creek Dam (site 9) on July 

22. More than 17,000 acre-ft of flood runoff was stored 

in Crooked Creek Lake, which prevented flooding 

downstream.
THE FLOODS OF JULY 19-20,1977 31

FIGURE 14.-Continued.

CONEMAUGH RIVER BASIN

Peak flows on streams in the Conemaugh River basin, 

over which the storm centered, were among the 

greatest known in the Northeast. The relations of the 

1977 peak discharges in the Conemaugh River basin to 

size of drainage areas are shown in figure 16 and are 

compared with those outside of the basin and to other

known floods in the Northeast. On the main stem of the 

Conemaugh River and its three principal tributaries, 

Stony Creek, Little Conemaugh River, and Blacklick 

Creek, recurrence intervals of the peak discharges are 

estimated to be 100 years or more.

Many deaths and much property damage resulted 

from flooding in the lower half of the Stony Creek basin. 

Along Paint Creek and its tributaries, many homes were 

either destroyed or extensively damaged. (See fig. 17.)
32 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

WEST 

VIRGINIA

Base from U.S. Geological Survey 

1:500.000. State base map. 1977

30 40 KILOMETERS

EXPLANATION

A1 "Continuous-record and crest-stage

gaging site and site number 

A7 Miscellaneous site and site number

FIGURE 15.-Locations of flood-determination sites in western Pennsylvania. A, The general area. B, The Johnstown area.
THE FLOODS OF JULY 19-20,1977 33

40°13 40°13'

10 MILES

,23

v25

5 10 

EXPLANATION

Continuous-record and crest-stage 

gaging site and site number

15 KILOMETERS

Miscellaneous site and site number 

1=1 Breached dam

FIGURE 15.-Continued.

Seese Run, a tributary to Paint Creek, at Windber (site 

11) had a peak flow of 5,760 ft3/s, and Paint Creek at 

Windber (site 12) had a peak flow of 19,000 ft3/s. Respectively, these flows correspond to unit discharges of 1,240 

(ft3/s)/mi2 from a drainage area of 4.66 mi2 and 872 

(ft3/s)/mi2 from a drainage area of 21.8 mi2 .

On the main stem of Stony Creek at Ferndale (site 13), 

the peak discharge at the gaging station was 48,000 

ft3/s, the second highest since at least 1913. The estimated recurrence interval is 100 years, and the unit 

discharge is 106 (ft3)/mi2 . Stage and discharge 

hydrographs for this site are shown in figure 18.

The peak flow on Sams Run, a tributary to Stony 

Creek, was 1,600 ft3/s at Geistown (site 14). The unit 

discharge of 1,250 (ft3/s)/mi2 at Geistown was comparable to that on Paint Creek. The peak flow on Sams

Run at Lorain (site 15) was 2,960 ft»/s or 1,360 

(ft3/s)/mi2 .

Flooding of streams in the Little Conemaugh River 

basin was also extreme. Rainfall over the basin ranged 

from 4 in. in the upper end to the maximum reported 

amount of 12 in. near the lower end. The peak flow of 

the Little Conemaugh River at Summerhill (site 17), 

near the middle of the basin, was 8,670 ft3/s from a 

drainage area of 91.1 mi2 , or a unit discharge of 95 

(ft3/s)/mi2 . Flooding along the South Fork Little Conemaugh River, which joins the little Conemaugh several 

miles downstream from Summerhill, was even more 

significant. At Fishertown (site 20) the peak flow of the 

South Fork was 24,000 ft3/s from a drainage area of only 

52.6 mi2 , which corresponds to a unit discharge of 456 

(ft3/s)/mi2 .
34 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

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THE FLOODS OF JULY 19-20,1977 35

FIGURE 17.-Remains of several homes and a church along Little Paint Creek in Scalp Level. (Johnstown Tribune-Democrat photograph.)

Sandy Run, a tributary to the South Fork Little Conemaugh River, had the maximum known natural-runoff 

rate in the entire flood area-2,390 (ft3/s)/m2 . This was 

determined for a site just upstream from a breached 

water-supply dam (fig. 19). The peak flow at this site 

(site 21) was 14,000 ft3/s from a drainage area of 5.86 

mi2 . The failure of the dam probably caused little 

modification of the natural peak discharge. One mile 

downstream from the dam (site 22), the peak flow was 

15,300 ft3/s, or only 10 percent greater than the 

upstream inflow. Additional information on this and six 

other dam failures is included in the section Breached 

Dams.

The peak flow of the Little Conemaugh River at East 

Conemaugh (site 23), about 9 miles downstream from 

the South Fork, was 40,000 ft3/s, as shown by the 

discharge, hydrograph in figure 20. This is 40 percent 

higher than the previously known maximum in 1936 and 

is probably the largest since 1889, when a large dam on 

the South Fork failed.

Johnstown, at the confluence of Stony Creek and the 

Little Conemaugh River, had its worst flood since March

1936. Four to 8 ft of water, and much debris, covered 

most of the downtown area (figs. 21-24). At the City 

Hall building, the peak-flood level was about 10 ft below 

that of the 1936 flood and about 17 ft below the level of 

the disastrous 1889 flood (fig. 25). Flooding along the 

Conemaugh River in the northern part of Johnstown 

was 3 to 7 ft below that of 1936.

After the 1936 flood, channel improvements were 

made on the lower 4 miles of Stony Creek, the lower 1V2 

miles of the Little Conemaugh River, and on the Conemaugh River for another 3V2 miles. Without these improvements, the U.S. Army Corps of Engineers (1978) 

estimated that the 1977 flood in downtown Johnstown 

would have been about 11 ft higher, or 1 ft higher than 

the 1936 flood level.

Small streams in the northern part of Johnstown and 

in adjacent communities also experienced extremely 

high floodflows. For example, the peak flow of Elk Run 

in the Morrelville section of Johnstown (site 24) was 

1,900 ft3/s from a drainage area of 1.99 mi2 , or 955 

(ft3/s)/mi2 . Flood severity along one of several streams
36 JOHNSTOWN-WESTERN PENNSYLVANIA'STORM AND FLOODS OF JULY 19-20, 1977 

70 i i i 26

21

FIGURE 18. - Hydrographs of stage and discharge of Stony Creek at Ferndale (site 13).

just east of Johnstown is indicated by the destruction 

shown in figure 26.

Flooding was most disastrous downstream from 

Laurel Run Reservoir on Laurel Run, which flows into 

the Conemaugh River at the north end of Johnstown. 

High inflows, which exceeded the discharge capacity of 

the spillway, resulted in the overtopping and subsequent 

erosion of the dam's earthen embankment (fig. 27). 

About 2,000 ft upstream from the dam (site 26), the peak 

flow was estimated to be 10,500 ft3/s from a drainage

area of 7.56 mi2 . The peak discharge about a mile 

downstream from the dam (site 28) was computed to be 

37,000 ft3/s, more than three times as great as the 

upstream inflow. (See section Breached Dams for additional information.)

Red Run, a tributary to Laurel Run between the dam 

and the downstream measurement site, had the second 

highest of known natural-runoff rates. The peak flow at 

its mouth (site 27) was 4,000 ft3/s, or a unit discharge of 

2,000 (ft3/s)/mi2 . However, its contribution at the time of
THE FLOODS OF JULY 19-20,1977 37

FIGURE 19. -Aerial view of breach in Sandy Run Dam (Pennsylvania Air National Guard photograph.)

the dam failure is considered to have been negligible. 

Another tributary to Laurel Run, Wildcat Run, had a 

peak discharge at its mouth (site 29) of 2,440 ft3/s, or a 

unit discharge of 1,240 (ft3/s)/mi2 from a drainage area 

of 1.97 mi2 .

Flooding on the Conemaugh River between Johnstown and Conemaugh River Lake was also very severe. 

Flood levels were 3 to 6 ft higher than the previously 

known maximum levels of March 1936. The peak flow of 

115,000 ft3/s at Seward (site 30), which was about 50 

percent greater than the peak of 1936, is equivalent to a 

unit discharge of 161 (ft3/s)/mi2 . The recurrence interval 

for this peak flow is estimated to be greater than 100 

years. Stage and discharge hydrographs for the July 

1977 flood at Seward are shown in figure 28.

Severe flooding also occurred along Blacklick Creek, 

which empties into Conemaugh River Lake about 20 

miles downstream from Seward. At Josephine (site 31),

just upstream from Two Lick Creek, the peak flow was 

45,700 ft3/s or 238 (ft3s)/mi2 from a drainage area of 192 

mi2 . This discharge has a recurrence interval greater 

than 100 years and is more than twice the maximum 

discharge during Hurricane Agnes in June 1972, the 

previous maximum since the gage was established in 

1952.

Recurrence intervals greater than 100 years were 

estimated for the peak discharges at three other gaging 

sites in the Blacklick Creek basin. Peak discharges, 

drainage areas, and comparisons with the 1972 flood 

discharges (the previously known maximums at these 

sites) are as follows: Little Yellow Creek near 

Strongstown (site 35)-4,250, ft3/s from a drainage area 

of 7.36 mi2 , 5.2 times greater; Yellow Creek near Homer 

City (site 36)-15,000 ft3/s from a drainage area of 57.4 

mi2 , 3.7 times greater; and Two Lick Creek at Graceton 

(site 38)-32,000 ft3/s from a drainage area of 171 mi2 , 

1.6 times greater.
38 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977 

80

JULY, 1977 

FIGURE 20.-Hydrographs of stage and discharge of Little Conemaugh River at East Conemaugh (site 23).

Discharge records before 1951 are not available at 

present gaging sites in the Blacklick Creek basin. 

However, flow records for a discontinued gage on 

Blacklick Creek at Blacklick (Jarvis and others, 1936) indicate that 1977 peak flows in at least the lower reaches 

of Blacklick and Two Lick Creeks were the highest since 

at least 1905, when the record began. 

No flooding occurred downstream from Conemaugh
THE FLOODS OF JULY 19-20,1977 39

FIGURE 21.-Flooded business establishments in downtown Johnstown at Park Place. The peak stage was about 8 in. higher than the water

level shown. (Johnstown Tribune-Democrat photograph.)

River Lake because of storage in the reservoir. The 

maximum discharge from the dam, determined at the 

gaging station 2 miles downstream (site 39), was 23,600 

ft3/s. This is 16 percent less than the flow the U.S. Army 

Corps of Engineers (1978) considers to be downstream 

bankfull capacity. More significantly, it corresponds to 

an 88 percent reduction of the peak reservoir inflow of 

194,000 ft3/s, as computed by the U.S. Army Corps of 

Engineers (1978). About 170,000 acre-feet of runoff was 

stored in the reservoir, utilizing 64 percent of the total 

available flood-control storage.

SUSQUEHANNA RIVER BASIN

Peak stages and discharges in the West Branch 

Susquehanna River basin, although significant, were 

generally much less than those during previous major 

floods. At Bower (site 42), the peak flow on the mainstem West Branch Susquehanna River was 19,200 ft3/s, 

the fourth highest since at least 1889, when records 

were first collected. The estimated recurrence interval 

of this discharge is 30 years. The peak stage of 16.23 ft 

was 3.5 ft lower than the previously known maximum in 

March 1936. Significant flooding was also reported on 

two east bank tributaries, Chest and Clearfield Creeks. 

A recurrence interval of 15 years is estimated for the 

peak discharge of 602 ft3/s on Bradley Run near Ashville

(site 44), a tributary to Clearfield Creek. Peak flows on 

other Clearfield Creek tributaries farther downstream 

were even more significant, as illustrated in figure 16, 

for two ungaged sites, Brubaker Run at Dean (site 45) 

and North Witmer Run at Irvona (site 46). On the main 

stem of Clearfield Creek, downstream from these 

tributaries, the magnitude of flooding decreased rapidly. 

Near the mouth of Clearfield Creek, at Dimeling (site 

47), the recurrence interval for the peak flow of 9,210 

ft3/s is only 4 years.

The elongated rainfall pattern by the storms of July 

19-20, 1977 extended well into the Raystown Branch 

Juniata River basin and resulted in severe floods on 

several streams. The peak flow of Dunning Creek at 

Belden (site 56) was 19,400 ft3/s from a drainage of 172 

mi2 , the highest discharge since at least 1936. The recurrence interval of this flow is estimated to be greater 

than 100 years.

POTOMAC RIVER BASIN

Moderate to extreme flooding was reported on several 

small streams in the Potomac River basin, but because 

the area is so sparsely populated, damages were minor. 

A recurrence interval of 70 years is estimated for the 

peak flow of 3,000 ft3/s on Little Wills Creek at Bard
40 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

FIGURE 22.-Flooding at Franklin Street United Methodist Church in 

Johnstown. (Johnstown Tribune-Democrat photograph.)

(site 57). The corresponding peak stage of 11.00 ft is 

about 2 ft higher than any other since the record began 

in 1961.

SUMMARY OF FLOOD STAGES AND DISCHARGES

Peak stage and discharge data for the sites shown in 

figure 15 are presented in table 1. Data for the maximum flood previously known are included for each of 

the gaged sites. The 8-digit numbers listed in the second 

column of the table are permanent USGS station 

numbers. These are the same as those used in the annual 

USGS Water Data Report for Pennsylvania and were 

assigned to each site according to its downstream order.

Additional stage and discharge data for many of the 

sites are included in table 4, which also includes detailed 

site locations, gage descriptions, and other pertinent

facts about each site. Data in this table can be used to 

construct stage and discharge hydrographs for most 

gaged sites, generally for the period July 19-23, 1977. 

The volume of runoff for the specified periods is also 

shown.

Floodmark data are included in table 5 and can be 

used to estimate maximum flood levels along selected 

reaches of the following 27 streams in the Mahoning 

Creek and Conemaugh River basins:

Mahoning Creek basin:

Mahoning Creek 

Stump Creek 

Conemaugh River basin:

Conemaugh River 

Stony Creek 

Shade Creek 

Paint Creek 

Seese Run

Weaver Run 

Little Paint Creek 

Sams Run 

Solomon Run 

Little Conemaugh River 

Spring Run 

Trout Run

North Branch Little Conemaugh River 

South Fork Little Conemaugh River

Sandy Run 

St. Clair Run 

Laurel Run 

Blacklick Creek 

North Branch Blacklick Creek 

South Branch Blacklick Creek 

Two Lick Creek 

North Branch Two Lick Creek 

Buck Run 

Dixon Run 

Yellow Creek

BREACHED DAMS

Extremely high flows in the Conemaugh River basin 

resulted in the failure of seven earthfill gravity-type 

dams. The locations of the breached dams are shown on 

the map in figure 15B and are given in table 2, which 

also gives the age and size of each structure. Peak 

discharges were determined at sites upstream and 

downstream from the Sandy Run and Laurel Run Dams 

and downstream from three other dams. Site numbers 

for referencing the peak-flow data are given in the last 

column of table 2.

Figure 29 and 30 show profiles of the maximum watersurface elevations downstream from Laurel and Sandy 

Run Dams. Floodmark data used to construct the profiles are included in table 5.

Because of the destruction and deaths caused by these 

failures and by others in the past, flooding caused by 

the Laurel Run Dam was analyzed in detail. Flood
THE FLOODS OF JULY 19-20,1977 41

TABLE I.-Summary of flood stages and discharges

Maximum flood previously known

Site 

(fig. 15) Station Stream and place of determination

Drainage 

area 

(mi2 ) Period

Month 

and 

year

Gage 

height 

(feet)

Discharge 

(ft3/s) Date

Gage 

height 

(feet)

Flood of July 1977

Unit Recurrence 

Discharge discharge interval 

(fta/s) ((fWs)/mi2 ) (years)

Redbank Creek basin

i

2

03031950 

03032500

Big Run near Sprankle Mills

Redbank Creek at St. Charles

7.38 

528

1963-77 

1910-77

Feb. 1966 

Feb. 1975 

Mar. 1936

6.23 

6.12 

!18.60

822 19

858 

50,000 20

6.22 

14.72

960 

19,500

130 

37

15

5

Mahoning Creek basin

3

4 

5

6

03033220 

03034000 

03034500

03036000

Stump Creek at Big Run

Mahoning Creek at Punxsutawney ____ 

Little Mahoning Creek at McCormick _

Mahoning Creek at Mahoning Creek 

Dam.

26.8

158 

87.4

344

1936-77 

1939-77

1938-77

June 1972 

June 1972 

Feb. 1977 

Mar. 1942

15.94 

13.20 

2 14.03 

8.10

17,300 20 

6,200 20

3 10,400 22

16.22 

12.77

7.35

5,240 

12,700 

5,770

36,560

196

80 

66

19

40 

20

3

Crooked Creek basin

7 

8 

9

03037300 

03038000 

03039000

Crooked Creek at Shelocta

Crooked Creek at Idaho

Crooked Creek at Crooked Cr. Dam ___

117 

191

278

1936-77 

1909-77

Mar. 1936 

Mar. 1936

18.6 

17.86

19,400 20 

21,000 22

13.38 

7.65

9,940 

38,860 

4,150

85 

46 

15

10 

1

Conemaugh River Basin

10

11

12 

13 

14 

15

16

17 

18 

19

20 

21 

22

23

24 

25 

26

27 

28

29 

30 

31

32 

33

34

35 

36

37 

38 

39

03039200

03039910 

03039914 

03040000 

03040016 

03040018

03040095

03040300 

03040420 

03040430

03U405UO 

03040503 

03040505

03041000

03041030 

03041038 

03041039

03041040 

03041043

U3041U46 

03041500 

03042000

03042170 

03042180 

03042198

03042200 

03042280

03042282 

03042500 

03044000

Clear Run near Buckstown

Seese Run at Windber

Paint Creek at Windber

Stony Creek at Ferndale

Sams Creek at Geistown

Sams Run at Lorain

North Branch Little Conemaugh 

River tributary near Ebensburg. 

Little Conemaugh River at Summerhill 

Otto Run at Salix

South Fork Little Conemaugh 

River tributary at St. Michael. 

South Fork Little Conemaugh River at 

Fishertown. 

Sandy Run above Sandy Run Reservoir 

near St. Michael. 

Sandy Run below Sandy Run Reservoir 

at St. Michael.

Little Conemaugh River at East 

Conemaugh. 

Elk Run at Morrellville

Laurel Run at Chickaree

Laurel Run above Laurel Run 

Reservoir near Coopersdale. 

Red Run near Coopersdale

Laurel Run below Laurel Run 

Reservoir near Coopersdale. 

Wildcat Run at Coopersdale

Conemaugh River at Seward

Blacklick Creek at Josephine

Stoney Run at Indiana

Two Lick Creek near Homer City

Little Yellow Creek tributary at 

Strongs town. 

Little Yellow Creek near Strongstown

Yellow Creek near Homer City

Ferrier Run near Homer City

Two Lick Creek at Graceton _________ 

Conemaugh River at Tunnelton

3.68 

4.66

21.8

451 

1.28

2.17

.80

91.1 

3.70

1.70 

52.6 

5.86 

7.61

183 

1.99

.055

7.56 

2.00

11.0 

1.97

715 

192

4.39 

95.5

.76 

7.36 

57.4

2.14 

171 

1,358

1961-77

1913-77

1936-77

1936-77 

1952-77

1963-77

1959-77 

1967-77

1951-77 

1939-77

Feb. 1961 

June 1972

Mar. 1936

Mar. 1936 

June 1972

Mar. 1936 

June 1972

Sept. 1974

June 1972

Feb. 1971 

June 1972

June 1972 

Mar. 1945

!5.30 

4.53

'30.26

10.48

22.95 

13.99

8.87

6.10

2 8.37 

7.46

14.69 

21.0

20

266

3 59,000 20

3 28,800 20 

3 16,600

S 75,000 20 

20,800 20

505

820 20 

20

4,100

3 19,600 20 

3 59,200 21

5.03

23.21

18.85

27.06 

19.89

5 10-11

9.31

12.60

18.65 

11.98

366

5,760 

19,000 

3 48,000 

1,600 

2,960

'1,040

8,670 

"2,120 

44,300

24,000 

14,000 

"15,300

3 40,000

1,900 

19

10,500

4,000 

"37,000

2,440 

3 115,000 

45,700

16,500 

1,450

4,250 

3 15,000

890 

332,000 

323,600

99

1,240 

872 

106 

1,250 

1,360

1,300

95 

573 

2,530

456 

2,390 

2,010

219

955 

345 

1,390

2,000 

3,360

1,240 

161 

238

173 

1,910

577 

261

416 

187 

17

30

100

>100

_____

>100

>100

>100 

>100

>100 

3

West Branch Susquehanna River basin

40 

41 

42 

43

44 

45 

46 

47 

48

01540600 

01540650 

01541000 

01541200

01541308 

01541321 

01541365 

01541500 

01542000

West Branch Susquehanna River at 

Barnesboro. 

West Branch Susquehanna River at 

Cherrytree. 

West Branch Susquehanna River at 

Bower. 

West Branch Susquehanna River at 

Curwensville. 

Bradley Run near Ashville ___________ 

Brubaker Run at Dean

North Witmer Run at Irvona

Clearfield Creek at Dimeling

Moshannon Creek at Osceola Mills ____

25.8 

58.8 

315 

367

6.77 

3.82

30.8 

371 

68.8

1889-1977 

1955-77 

1967-77

1913-77 

1940-77

June 1972 

Mar. 1936 

Mar. 1964 

June 1972

Mar. 1936 

June 1972

19.74 

14.19 

3.82

'18.49

14.25

6,790

31,500 20 

15,700 23 

679 20

30,600 20 

5,120 20

16.23 

8.47 

3.65

11.27 

1.97

2,400 

6,000 

19,200 

3 5,660

602 

1,370 

10,000 

39,210 

339

93 

102 

61 

15

89 

359 

325 

25 

5

30 

3 

15

4 

1
42 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977 

TABLE 1.-Summary of flood stages and discharges-Continued

Maximum flood previously known

Site 

(fig. 15) Station Stream and place of determination

Drainage 

area 

(mi*)

Month Gage 

and height Discharge 

Period year (feet) (fts/s) Date

Flood of July 1977

Gage 

height 

(feet)

Unit Recurrence 

Discharge discharge interval 

(ft3/s) ((ft3/s)/mi2) (years)

Juniata River basin

49

50 

51 

52 

53

54

55

56

01556000

01556400 

01556500 

01557100 

01557500

01558000

01559700

01560000

Frankstown Branch Juniata River

at Williamsburg. 

Sandy Run near Bellwood

Little Juniata River at Tipton

Schell Run at Tyrone

Bald Eagle Creek at Tyrone

Little Juniata River at Spruce Creek _

Buffalo Run tributary near

Manns Choice. 

Dunning Creek at Belden

291

5.58 

93.7 

1.68 

44.1

220

5.28

172

1889-1977 June 1889 19.1

1962-77 Sept. 1967 6.25 

1946-77 June 1972 9.24 

1958-77 July 1969 3.00 

1936-77 Mar. 1936 ^5 

Nov. 1950 '7.5 

1936-77 Mar. 1936 19.1

1961-77 Sept. 1967

1936-77 Mar. 1936

4.26

6 17.8

35,500

900 

6,140 

225

5,140 

39,800

1,010

16,900

20

20 

20 

20 

20

20

20

20

8.11

5.89 

9.07 

1.97 

1.41

7.52

5.12

14.15

2,930

550 

5,580 

45 

112

5,760

1,120

19,400

10

99 

60 

27 

3

26

212

113

1

10 

10

1 

1

3

20

>100

Potomac River Basin

57 01600700 Little Wills Creek at Bard 10.2 1961-77 Sept. 1967 8.91 1,100 20 11.00 3,000 294 70

1 Different site or datum.

* Backwater from ice.

3 Regulated by reservoirs upstream.

* Downstream of breached dam.

6 Peaked 1-2 feet above gage.

6 Backwater from Raystown Branch Juniata River.

FIGURE 23.-Flooding at Johnstown's Lee Hospital. The dark line across the center of the photograph shows the maximum flood level.

(Johnstown Tribune-Democrat photograph.)
HISTORICAL FLOODS 43

TABLE 2.-Breached dams

[Data furnished by the Pennsylvania Department of Environmental Resources]

Stream and location

Sandy Run near St. Michael

Laurel Run near Coopersdale

Otto Run at Salix

South Fork tributary at St. Michael 

North Branch tributary 

near Ebensburg. 

Peggys Run at Franklin __________ 

Little Paint Creek at Elton

Latitude

40°19'40"

40°23'05"

40°17'40"

40°19'30" 

40°28'20"

40°20'10" 

40°16'50"

Longitude

78°48'10"

78°54'55"

78°45'35"

78°46'20" 

78°41'30"

78°53'00" 

78°47'15"

Date 

built

1915

1914

1956

Unknown _ 

Unknown _

Unknown _

Drainage 

area 

(mi2)

5.6

7.9

1.9

1.5 

.65

1.1 

1.5

Surface 

area at 

normal 

pool 

elevation 

(acres)

8

22

2

2 

2.2

3

Storage 

capacity 

at 

spillway 

elevation 

(106 gal)

15

101

2

1

6 

3

Height 

(feet)

28

42

19

6 

18

12 

10

Number of 

site at 

which peak 

flow data 

are provided 

(see table 1)

21,22

26,28

18

19 

16

None. 

None.

FIGURE 24.-Stony Creek near the height of the flood. View is of Haynes Street bridge looking downstream toward Johnstown's business

district. (Johnstown Tribune-Democrat photograph.)

hydrographs describing inflow to the reservior and the 

flows of major tributaries were constructed from rainfall data collected in and near the Laurel Run basin. 

These data were used, along with reservoir and channel 

cross-sections, to verify a dam-break flood-wave-routing 

model. Armbruster (1978) gives a brief discussion of the 

model.

HISTORICAL FLOODS

Throughout its history, the area discussed in this 

report has had an uncommonly high frequency of 

flooding. The relatively narrow, steep-sided valleys 

characteristic of much of the area are probably a major 

factor contributing to its high flood potential. The
44 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

FIGURE 25.-Maximum heights of the 1889, 1936, and 1977 floods at 

Johnstown's City Hall at northeast corner of Main and Market 

Streets. (U.S. Geological Survey photograph.)

severity of floods just west of the Ohio River-Susquehanna River drainge divide has also been attributed 

to increased rainfall intensities resulting from 

orographic uplift. Other factors are the area's position 

relative to the tracks of most Northeastern United 

States storms and its proximity to a large source of 

moisture, the Great Lakes. Flood plain development has 

also increased the damage potential of flooding in many 

parts of the report area, especially in the Johnstown 

area, which has had three devasting floods within the 

last 90 years.

The May 31, 1889 flood, commonly referred to as "the 

Johnstown Flood", was one of the worst catastrophies 

ever in the United States. About 2,200 persons died, and 

nearly 1,000 persons were reported missing, and believed to have died as a result of the failure of an 80 ft 

high dam on the South Fork Little Conemaugh River, 13 

miles upstream from Johnstown. Just before the failure,

Johnstown and surrounding areas were experiencing 

severe floods as a result of 6 to 8 in. of storm rainfall the 

preceding day. Runoff from the storm had also caused 

the water level behind the South Fork Dam to rise far 

above normally safe levels. As the water level continued 

rising, leaks were reported in the dam's earthen embankment. Accounts of the failure (Shank, 1972) state 

that the leaks progressively worsened and that at about 

3:00 p.m. (May 31), the dam suddenly burst, releasing 

about 20 million tons of water on the flooded valley 

below. The resulting flood wave estimated at 30 to 40 ft. 

Seven small towns were destroyed as the wave travelled 

the 13 miles to Johnstown in about 15 minutes. Downtown Johnstown, at the mouth of the Little Conemaugh 

River and directly in the path of the flood wave, was 

almost destroyed. A stone, multi-arched railroad bridge 

over the Conemaugh River in Johnstown was able to 

withstand the wave, which greatly reduced damages 

farther downstream.

Though overshadowed by the catastrophe at Johnstown, floods on other streams in the area on May 31 and 

June 1,1889, were also severe. It was the highest known 

flood on the Frankstown Branch Juniata River at 

Williamsburg (site 49), where the peak stage was at 

least 0.5 ft higher than any that have occurred since 

1889, and the second highest known on the West Branch 

Susquehanna River at Bower (site 42).

Flooding occurred frequently in the Johnstown area 

during the next four decades, but not until March 1936 

was flooding severe and widespread enough to rival that 

in 1889. Nearly the entire Northeast was affected by 

floods during March 1936, which resulted from combinations of snowmelt and storm runoff.

Although there was some melting of the abnormally 

deep snowpack by the end of February 1936, the major 

thaw did not begin until March 9, initiated by 

unseasonably warm temperatures and 1 to 2 in. of rainfall. The snowmelt and runoff associated with the first 

storm did not cause flooding, but they did increase the 

potential for flooding. The second series of storms 

beginning on March 16 brought 5 to 8 in. of rain, most of 

which fell on March 17. Runoff from these storms, combined with further melting, produced floods comparable 

to that of 1889 in much of the area. Downtown 

Johnstown was inundated by 15 to 20 ft of water, the 

maximum known for a naturally produced flood. It was 

the greatest known flood on Stony Creek at Ferndale 

(site 13), where records are available since 1913, and 

also at seven gaging sites in the report area but outside 

the Conemaugh River basin.

At Johnstown, Stony Creek and the Little Conemaugh 

and Conemaugh Rivers were realigned and partly 

paved, so that flood flows equivalent to the March 1936 

flood would be contained within their channel banks.

(Text continued on p. 54.)
HISTORICAL FLOODS 45

FIGURE 26. - Destruction along an unnamed tributary to the Conemaugh River between the Coopersdale and Minersville sections of 

Johnstown. The drainage area above this site is about 0.5 mi2 . (Pennsylvania Air National Guard photograph.)
46 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

FIGURE 27.-(See caption on facing page.)
HISTORICAL FLOODS 47

FIGURE 27.-Laurel Run Dam. A,The left photograph shows the view looking downstream through the breach. (Pennsylvania Air National 

Guard photograph). B, The right photograph shows the eroded downstream face of the dam. The breach is at the far end. (U.S. Geological 

Survey photograph.)
48 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

160 , , , , 30

140

19

JULY, 1977 

FIGURE 28.-Hydrographs of stage and discharge of the Conemaugh River at Seward (site 30).
HISTORICAL FLOODS 49

1500

o

LLI 

Q 

O 

LLI

o -

I- u-

< O

MAXIMUM RESERVOIR ELEVATION= 1437.8

1400

1300

u_ htr

1200

1100

2 1 

DISTANCE, IN MILES ABOVE MOUTH

FIGURE 29.-Flood-crest profile below Laurel Run Dam.
50 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

o

O

LU 

Q 

O 

111

(D

O -

I- LL.

< O

1900

1800

1700

1600

1500

MAXIMUM RESERVOIR ELEVATION= 1810.5

2 1

DISTANCE, IN MILES ABOVE MOUTH

FIGURE 30.-Flood-crest profile below Sandy Run Dam.
HISTORICAL FLOODS 51

FIGURE 31. - Flood damage downstream from the Laurel Run Dam. The foundations of two homes that were washed away are visible in the

upper left corner (Pennsylvania Air National Guard photograph).
52 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

FIGURE 32.-Eastbound lanes of State Highway 56, near Johnstown's eastern corporate boundary, undermined by floodwaters from Solomon

Run (Pennsylvania Air National Guard photograph).
HISTORICAL FLOODS 53

FIGURE 33.-Home damaged by flooding from Solomon Run in the Walnut Grove section of Johnstown (Johnstown Tribune-Democrat

photograph.)
54 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

FIGURE 34.-Flooding in the Hornerstown section of Johnstown 

(Johnstown Tribune-Democrat photograph.)

Since its completion in 1943, this channelization was 

twice credited with preventing serious floods at 

Johnstown, once in October 1954 and again in June 

1972.

DEATHS AND DAMAGES

The Great Johnstown Flood of 1977, as described by 

many residents, was among the more devasting floods in 

the history of the United States, as shown in table 3. It is 

especially noteworthy when one considers the size of the 

area affected. Most of the property damage occurred 

within a 200-mi2 area, whereas other floods listed in 

table 3 generally occurred over areas that are 10-1,000 

times larger.

Although damages have not been officially compiled in 

detail, the total may exceed the estimated $330 million 

(National Oceanic and Atmospheric Administration, 

1977), as indicated by the following estimates. A 

spokesman for the Greater Johnstown Chamber of ComTABLE 3. -Losses in individual severe floods in the United States since 

July 1902

[Adapted from National Oceanic and Atmospheric Administration (1977) and includes only 

those floods resulting in 60 or more deaths or property losses in excess of $200 million]

Date

May-June 1903 

Mar. 1913

Dec. 1913

June 1921 

Sept. 1921

Spring, 1927

Nov. 1927

May-June 1935

Mar.-Apr. 1936

Jan.-Feb. 1937

Mar. 1938

July 1939

May-July 1947 

June-July 1951

Aug. 1955 

Dec. 1955

Dec. 1964

June 1965

Jan.-Feb. 1969

Feb. 1972

June 1972

June 1972

Spring, 1973

June-July 1975

Sept. 1975 

June 1976

July 1976

Apr. 1977

July 1977

Location

Kansas, lower Missouri, and upper Mississippi 

Rivers. 

Ohio River and tributaries

Texas rivers

Arkansas River in State of Colorado ________ 

Texas rivers

Mississippi Valley

New England rivers

Republican and Kansas Rivers

Rivers in Eastern United States _____________

Ohio and lower Mississippi River basins

Streams in Southern California

Licking and Kentucky Rivers

Lower Missouri and middle Mississippi River 

basins. 

Kansas and Missouri

Hurricane "Dianne" floods in the northeastern 

United States. 

West Coast rivers

California and Oregon

South Platte River basin

Floods in California

Buffalo Creek, West Virginia

Black Hills of South Dakota

Hurricane "Agnes" floods in the eastern 

United States.

Mississippi River basin

Red River of the North basin

Hurricane "Eloise" floods in Puerto Rico and 

northeastern United States. 

Teton Dam failure in southeast Idaho

Big Thompson River in Colorado

Southern Appalachian Mountains area

Johnstown-Western Pennsylvania

Lives 

lost

100 

467

177

120 

215

313

88

110

107

137

79

78

29 

28

187 

61

40

16

60

125

237

105

33

<10

50 

11

139

22

78

Property 

damage 

(thousands 

of dollars)

40,000 

147,000

9,000

25,000 

19,000

284,000

45,578

18,000

270,000

417,685

24,500

1,715

235,000 

923,224

714,079 

154,532

415,832

415,076

399,233

10,000

164,947

4,019,721

1,154,770

273,114

470,274 

1,000,000

30,000

424,000

330,000

merce, reported that 640 dwelling units were destroyed 

and another 2,600 sustained major damages, a loss of 

about $26 million. Also, 405 business structures were 

destroyed, of which more than half were in downtown 

Johnstown, where business damages totalled $136 

million. In addition, the Bethlehem Steel Corp., the 

area's largest employer, estimated that damages to its 

facilities would total $35-40 million.

A report by the Pennsylvania House of Representatives (1976) lists railroad damage at $20 million and 

states that damages to the area's utilities were in excess 

of $20 million, mostly properties of the Pennsylvania 

Electric Co. Other estimates of damage listed in the 

Johnstown Tribune-Democrat include $94 million of 

roadway and bridge repair and $62.7 million for repairs 

to public facilities. Also, 3,300 motor vehicles and 8.2 

million pounds of food were estimated to have been 

destroyed. The photographs in figures 31-34 show 

scenes of the destruction in the Johnstown area.

At least 78 lives were lost as a direct result of the 

flood. Also, eight others, who were listed as missing 1 

year later, probably died. Flooding along Laurel Run, 

downstream from the breached dam, was responsible 

for about half of the fatalilties. Many also died along 

Solomon Run, in the south part of Johnstown, and along 

the Conemaugh River near Seward.
REFERENCES 55

REFERENCES

Armbruster, J. T., 1978, Model of the flooding caused by the failure of 

the Laurel Run Reservoir dam, July 19-20,1977, near Johnstown, 

Pennsylvania: Preprints, conference on Flash Floods: 

Hydrometeorological Aspects: American Meterorological Society, 

Los Angeles, Calif., p. 190-193.

Bailey, J. F., Patterson, J. L., and Paulhus, J. L. H., 1975, Hurricane 

Agnes rainfall and floods, June-July 1972: U.S. Geological Survey 

Professional Paper 924, 403 p.

Bodhaine, G. L., 1968, Measurement of peak discharge of culverts by 

indirect methods: U.S. Geological Survey Techniques of WaterResources Investigations, book 3, chap. A3, 60 p.

Brua, S. A., 1978, Floods of July 19-20, 1977 in the Johnstown area, 

western Pennsylvania: U.S. Geological Survey open-file report, 

62 p.

Crippen, J. R., and Bue, C. D., 1977, Maximum flood flows in the conterminous United States: U.S. Geological Survey Water-Supply 

Paper 1887, 52 p.

Dalrymple, Tate, and Benson, M. A., 1967, Measurement of peak 

discharge by the slope-area method: U.S. Geological Survey 

Techniques of Water-Resources Investigations, book 3, chap. A2, 

12 p.

Greene, D. R., and Saffle, R. E., 1978, Radar analysis of the 1977 

Johnstown flash flood: Preprints, Conference on flash floods; 

Hydrometeorological Aspects, American Meteorological Society, 

Los Angeles, California, p. 176-180.

Hoxit, L. R., and others, 1978, Meteorological analysis of the Johnstown, Pennsylvania, flash flood, July 19-20, 1977: NOAA 

Technical Report ERL 401-APCL 43, 71 p.

Hulsing, Harry, 1967, Measurement of peak discharges at dams by 

indirect method: U.S. Geological Survey Techniques WaterResources Investigations book 3, chap. A5, 29 p.

Jarvis, C. S., and others, 1936, Floods in the United States, magnitude 

and frequency: U.S Geological Survey Water-Supply Paper 771, 

p. 170-171.

Langbein, W. B., and Iseri, K. T., 1960, General introduction and 

hydraulic definitions: U.S. Geological Survey Water-Supply Paper 

1541-A, 29 p.

Lott, G. A., 1976, Precipitable water over the United States, Volume 

1: Monthly means: National Oceanic and Atmospheric Administration Technical Report NWS 20, 1973 p.

Maddox, R. A., Hoxit, L. R., Chappel, C. F., and Caracena, F., 1978, 

Comparison of meteorological aspects of the Big Thompson and 

Rapid City floods: Monthly Weather Review, v. 106, p. 375-389.

Maddox, R. A., Chappel, C. F., and Hoxit, L. R., 1979, Synoptic and 

meso-a scale aspects of flash flood events: Bulletin of the American 

Meteorological Society, v. 60, no. 2, p. 115-123.

Magor, B. W., 1959, Mesoanalysis: some operational analysis techniques utilized in tornado forecasting: Bulletin of the American 

Meteorological Society, v. 40, p. 499-511.

Matthai, H. F., 1967, Measurement of peak discharge at width 

contractions by indirect methods: U.S. Geological Survey Techniques of Water-Resources Investigations, book 3, chap. A4, 44 p.

Maurwitz, J. D, 1972. Precipitation efficiency of thunderstorms on the 

high plains. Journal de Recherches Atmospheriques (Dessens 

Memorial Issue), v. 6, p. 367-370.

Mogil, H. M., and Groper, H. S., 1976, On the short range prediction 

of localized excessive convective rainfall: Preprints, Conference on 

Hydrometeorology: American Meteorological Society, Fort 

Worth, Tex., p. 9-12.

National Oceanic and Atmospheric Adminstration, 1977, Climatological Data, National Summary, Annual Summary: v. 28, no. 13, 

p. 119-120.

Pennsylvania House of Representatives, 1977, House Speaker's Ad 

Hoc Committee on the eight county flood of July 19-20,1977, final 

report, Wednesday, December 14, 1977: 30 p.

Shank, W. H., 1972, Great Floods of Pennsylvania, 1972 Flood Edition: Buchart-Horn Publication, 88 p.

U.S. Army Corps of Engineers, Pittsburgh District, 1974, Flood plain 

information, Conemaugh and Little Conemaugh Rivers, Stony and 

Bens Creek, City of Johnstown and Vicinity, Cambria and 

Somerset Counties, Pennsylvania: 59 p., 5 pi.

 1977, Floodmark data for Flood of July 19-20, 1977 

[unpublished] on file in Pittsburgh, Pa., office, U.S. Army Corps of 

Engineers. 

-1978, The 1977 Southwestern Pennsylvania Flood: 75 p.

U.S. Geological Survey, 1974, Hydrologic Unit Map-1974, State of 

Pennsylvania: scale, 1:500,000.

U.S. Water Resources Council, 1977 Guidelines for determining flood 

flow frequency: Bulletin 17A of the Hydrology Committee, 

Washington, D.C., U.S. Government Printing Office, 197 p.

TABLES 4 AND 5

TABLES 59

TABLE 4. -Site descriptions and gage-height and discharge data.

[Site numbers used in this table are the same as those used in table 1 and figure 15. Hydrologic 

Unit numbers are included in the site description for each continuous-record gaging station. 

This number designates a geographic area representing part or all of a surface drainage 

basin or distinct hydrologic feature as delineated by the Office of Water Data Coordination, 

U.S. Geological Survey (1974). If needed, hourly stage and discharge data for times other 

than those shown should be determined either graphically or by linear interpolation]

SITE 1. 03031950. Big Run near Sprankle Mills, Pa.

Location. -Lat 40°59'30", long 79°05'26", Jefferson County, Hydrologic Unit 05010006, on 

the right bank at the downstream side of a highway bridge 0.5 mi (0.8 km) downstream from 

McCracken Run and 1.3 mi (2.1 km) southeast of Sprankle Mills. 

Gage. - Water-stage recorder and crest-stage gage. The altitude of the gage is 1,290 ft (393 m), 

from a topographic map.

Gage Dis- Gage Dis- Gage DisTime height charge Time height charge Time height charge 

(ft) (ft3/s) (ft) (ft3/s) (ft) (ft'/s)

July 19: July 20: July 21: 

0600 2.12 6.2 0100 5.38 588 0200 2.57 45 

1200 2.12 6.2 0200 5.69 706 0600 2.50 38 

1400 2.22 12 0300 5.86 774 1200 2.41 30 

1600 2.75 57 0400 5.71 714 1600 2.36 26 

1700 2.68 50 0500 5.27 550 

1800 2.51 35 0600 4.37 304 

1900 2.41 26 0800 3.53 160 

2000 3.26 114 1000 3.29 126 

2100 5.66 674 1200 3.15 108 

2200 6.07 838 1400 2.99 90 

2230 6.22 960 1600 2.88 78 

2300 6.13 905 1800 2.78 67 

2400 5.69 706 2000 2.68 56 

2200 2.63 51 

2400 2.60 48

Total runoff, in inches 1.96

SITE 2. 03032500. Redbank Creek at St. Charles, Pa.

Location. -Lat 40°59'40", long 79°23'40", Armstrong County, Hydrologic Unit 05010006, on 

the left bank 400 ft (120 m) downstream from a highway bridge on Legislative Route 03117 

at St. Charles, 0.3 mi (0.5 km) downstream from Leatherwood Creek, and 3 mi (5 km) west 

of New Bethlehem. A water-quality sampling site is 400 ft (120 m) upstream. 

Gage.- Water-stage recorder. Datum of the gage is 973.14 ft (296.613 m) NGVD, datum of 

1912. Prior to July 10, 1940, a nonrecording gage was at a site 500 ft (150 m) upstream, at a 

datum 3.10 ft (0.94 m) higher.

Gage Dis- Gage Dis- Gage DisTime height charge Time height charge Time height charge 

(ft) (fts/s) (ft) (fWs) (ft) (ft3/s)

July 19: July 20: July 22:

0100 4.74 830 0900 14.65 19,300 0200 7.77 3,800 

0600 4.63 775 1000 14.50 18,800 0600 7.56 3,530 

1200 4.51 715 1100 14.18 17,700 0800 7.42 3,350 

1800 4.50 710 1200 13.78 16,400 1200 7.23 3,100 

2000 4.54 730 1400 12.83 13,700 1800 6.88 2,660 

2100 4.76 840 1600 11.94 11,400 2400 6.62 2,340 

2200 5.19 1,070 1800 11.21 9,760 July 23: 

2300 5.82 1,560 2000 10.60 8,500 0600 6.40 2,100 

2400 6.75 2,500 2200 10.03 7,450 1200 6.19 1,890 

July 20: 2400 9.52 6,540 1800 5.97 1,680 

0100 7.79 3,830 July 21: 2400 5.75 1,500 

0200 8.98 5,570 0200 9.11 5,800 July 24: 

0300 10.86 9,020 0400 8.78 5,250 0600 5.55 1,340 

0400 12.46 12,700 0600 8.52 4,830 1200 5.37 1,200 

0500 13.23 14,800 1200 7.98 4,070 1800 5.21 1,090 

0600 13.67 16,100 1800 7.79 3,830 2400 5.07 1,000 

0700 14.15 17,500 2000 7.82 3,870 

0800 14.52 18,900 2200 7.90 3,970 

0830 14.72 19,500 2400 7.82 3,870

Total runoff, in inches 1.65

TABLE 4. -Site description and gage-height and discharge dataContinued 

SITE 3. 03033220. Stump Creek at Big Run, Pa.

Location. -Lat 40°58'39", long 78°50'48", Jefferson County, at the Baltimore and Ohio 

Railroad bridge 0.5 mi (0.8 km) upstream from the mouth, 1.0 mi (1.6 km) northeast of Big 

Run, and 5.6 mi (9.0 km) south of Sykesville. 

Gage. -Miscellaneous site.

SITE 4. 03034000. Mahoning Creek at Punxsutawney, Pa.

[NOTE: Gage height and discharges are estimated beginning at 1800 hours on July 21] 

Location. - Lat 40°56'21", long 79°00'31", Jefferson County, Hydrologic Unit 05010006, on the 

right bank 75 ft (23 m) downstream from Williams Run, 1.9 mi (3.1 km) downstream from 

Sawmill Run, and 2 mi (3 km) west of Punxsutawney 

Gage.- Water-stage recorder. Datum of the gage is 1,206.14 ft (367.631 m) NGVD of 1925. 

(Corps of Engineers bench mark). Prior to October 1, 1946, the gage was at a site 2.9 mi (4.7 

km) upstream, at a datum 13.30 ft (4.054 m) higher.

Gage Dis- Gage Dis- Gage DisTime height charge Time height charge Time height charge 

(ft) (ft3/s) (ft) (ft3/s) (ft) (ft3/s)

July 19: July 20: July 21: 

0100 2.77 478 0100 6.42 2,970 0200 7.40 2,760 

0600 2.68 442 0200 8.22 4,610 0600 6.60 2,240 

1200 2.60 410 0300 10.20 6,740 1200 6.34 2,080 

1300 2.58 403 0400 11.30 8,170 1800 6.00 1,900 

1400 2.60 410 0500 12.52 8,860 2000 5.90 1,850 

1600 2.89 526 0600 13.62 9,740 2200 6.25 2.030 

1800 3.06 610 0700 14.78 11,200 2400 6.40 2,120 

2000 3.26 710 0800 15.68 12,200 July 22: 

2100 3.58 878 0915 16.22 12,700 0600 5.95 1,880 

2200 4.21 1,300 1000 16.13 12,400 1200 5.50 1,650 

2300 4.92 1,790 1100 16.00 12,100 1800 5.10 1,450 

2400 5.44 2,160 1200 15.57 11,200 2400 4.70 1,250 

1400 14.46 9,750 July 23: 

1600 13.14 8,170 0600 4.40 1,100 

1800 11.78 6,780 1200 4.05 925

2400 8.14 3,350

Total runoff, in inches 3.16

SITE 5. 03034500. Little Mahoning Creek at McCormick, Pa.

Location. -Lat 40°50'10", long 79°06'37", Indiana County, Hydrologic Unit 05010006, on the 

left bank 200 ft (60 m) upstream from the highway bridge at McCormick, 1 mi (2 km) west of 

Georgeville, 1.7 mi (2.7 km) upstream from Ross Run, and 4 mi (6 km) southeast of 

Smicksburg. 

Gage.- Water-stage recorder. Datum of the gage is 1,164.88 ft (355.055 m) NGVD of 1929. 

(Corps of Engineers bench mark). Prior to May 10, 1940, a nonrecording gage was at a site

200 ft (60 m) upstream, at the same datum.

Gage Dis- Gage Dis- Gage DisTime height charge Time height charge Time height charge

(ft) (fts/s) (ft) (ft3/s) (ft) (ft3/s)

July 19: July 20: July 21: 

0100 2.00 58 1000 12.42 5,420 1400 5.19 767 

0600 1.94 53 1100 12.68 5,680 1500 5.10 740 

1200 1.89 48 1200 12.76 5,760 1600 5.75 960 

1800 1.91 50 1230 12.77 5,770 1800 7.15 1,520 

1900 1.92 51 1300 12.77 5,770 2000 7.64 1,720 

2000 2.23 82 1400 12.68 5,680 2200 8.19 2,030 

2100 2.33 94 1500 12.53 5,530 2400 8.80 2,400 

2200 2.66 138 1600 12.30 5,300 July 22: 

2300 3.15 230 1700 12.00 5,000 0200 9.20 2,650 

2400 3.97 425 1800 11.63 4,630 0230 9.21 2,660 

July 20: 2000 10.69 3,750 0300 9.19 2,640 

0100 5.69 896 2200 9.48 2,850 0400 9.04 2,540 

0200 6.86 1,400 2400 8.24 2,060 0600 8.43 2,180 

0300 7.70 1,750 July 21: 1200 6.43 1,230 

0400 8.77 2,380 0200 7.15 1,520 1800 5.57 888 

0500 9.81 3,080 0400 6.51 1,260 2400 4.92 686 

0600 10.35 3,480 0600 6.14 1,120 July 23: 

0700 10.80 3,840 0800 5.85 1,000 0600 4.54 572

0800 11.32 4,320 1000 5.60 900 1200 4.27 498

Total runoff, in inches _ 2.99
60 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

TABLE 4. -Site description and gage-height and discharge dataContinued

SITE 6. 03036000. Mahoning Creek at Mahoning Creek Dam, Pa.

Location.-Lat 40°55'39", long 79°17'29", Armstrong County, Hydrologic Unit 05010006, on 

the left bank at the downstream side of the highway bridge at McCrea Furnace, 700 ft (213 

m) downstream from Camp Run, 0.9 mi (1.4 km) downstream from Mahoning Creek Dam, 1 

mi (2 km) southwest of Eddyville, and 2.1 mi (3.4 km) upstream from Pine Run. 

Gage.- Water-stage recorder. Datum of the gage is 1,003.39 ft (305.833 m) NGVD of 1929 

(Corps of Engineers bench mark). Prior to February 1, 1940, a nonrecording gage was at the 

same site and datum. 

Remarks. -Flow has been completely regulated since 1941 by Mahoning Creek Lake, 0.9 mi 

(1.4 km) upstream.

Gage Dis- Gage Dis- Gage DisTime height charge Time height charge Time height charge 

(ft) (ft3/s) (ft) (ft3/s) (ft) (ft3/s)

July 19: July 20: July 22: 

0100 3.84 1,020 1200 3.55 815 0100 6.88 5,400 

0600 3.83 1,010 1400 3.53 801 1200 6.88 5,400 

1200 3.81 998 1600 3.89 1,060 1345 7.35 6,560 

1300 3.20 590 1800 3.94 1,100 1400 7.35 6,560 

1800 3.08 530 2000 4.86 1,930 1700 7.35 6,560 

2400 3.31 656 2200 4.90 1,970 1800 6.85 5,330 

July 20: 2400 4.93 2,000 2400 6.90 5,440 

0100 3.49 773 July 21: July 23: 

0200 4.32 1,420 0200 4.94 2,010 0600 6.99 5,660 

0300 4.60 1,670 0400 4.95 2,030 1200 7.00 5,690 

0400 4.13 1,250 0900 4.97 2,050 1800 7.00 5,690 < 

0500 3.85 1,030 1000 5.74 3,080 2400 7.01 5,720 

0600 3.75 955 1200 5.76 3,120 July 24: 

0800 3.68 906 1300 6.88 5,400 0600 7.01 5,720 

1000 3.60 850 2400 6.88 5,400 1200 7.02 5,740 

1800 7.02 5,740 

2400 7.02 5,740

Total runoff, in inches 2.47

SITE 7. 03037300. Crooked Creek at Shelocta, Pa.

Location.-Lat 40°39'35", long 79°18'40", Indiana County, 0.4 mi (0.6 km) upstream from 

State Highway 156 bridge and 0.5 mi (0.8 km) northeast of intersection of U.S. Highway 422 

and State Highway 156, at Shelocta.

Gage. - Miscellaneous site.

SITE 8. 03038000. Crooked Creek at Idaho, Pa.

[NOTE: Gage heights and discharges estimated from 1800 hours on July 20 to 1000 hours on 

July 21] 

Location.-Lat 40°39'17", long 79°20'56", Armstrong County, Hydrologic Unit 05010006, on 

the right bank at the downstream end of the old bridge abutment at Idaho, 0.4 mi (0.6 km) 

downstream from Keystone Generating Station, 1.5 mi (2.4 km) downstream from Plum 

Creek, and 2.4 mi (3.9 km) west of Shelocta. 

Gage.- Water-stage recorder and concrete weir control. Datum of the gage is 961.04 ft 

(292.925 m) NGVD of 1929. (Baltimore and Ohio Railroad bench mark). 

Remarks. -Flow has been regulated to some extent since March 1968 by Keystone Lake, 7 mi 

(11 km) upstream, which has a usable capacity of 22,010 acre-ft (27.1 hm3). Evaporation 

from the operation of a steam-electric plant 0.4 mi (0.6 km) upstream, which began during 

July 1967, can amount to as much as 30 ft3/s (0.85 m3 /s).

Gage Dis- Gage Dis- Gage DisTime height charge Time height charge Time height charge 

(ft) (ft3/s) (ft) (ft3 /s) (ft) (ft3/s)

July 19: July 20: July 22: 

1200 2.48 51 1400 12.44 7,730 0200 7.52 3,510 

1500 2.61 72 1500 12.79 8,150 0400 7.66 3,610 

1800 2.76 102 1600 13.10 8,520 0600 7.75 3,680 

1900 2.76 102 1700 13.38 8,860 0700 7.76 3,680 

2000 2.80 111 1800 13.25 8,700 0800 7.73 3,660 

2100 3.38 340 1900 13.04 8,450 0900 7.63 3,590 

2200 4.33 951 2000 12.62 7,940 1000 7.46 3,480 

2300 5.59 1,920 2100 12.01 7,260 1200 6.92 3,040 

2400 6.85 2,980 2200 11.40 6,650 1400 6.28 2,500 

July 20: 2300 10.78 6,030 1600 5.82 2,110 

0100 7.48 3,480 2400 10.22 5,500 1800 5.50 1,850 

0200 7.93 3,800 July 21: 2400 4.83 1,310 

0300 8.30 4,060 0200 9.33 4,780 July 23: 

0400 8.68 4,330 0400 8.54 4,230 0600 4.45 1,040 

0500 9.08 4,610 0600 7.77 3,690 1200 4.25 895 

0600 9.54 4,930 0800 6.98 3,080 1800 4.05 755 

0700 9.93 5,240 1000 6.19 2,420 2400 3.87 629 

0800 10.30 5,570 1200 5.44 1,800 July 24: 

0900 10.67 5,920 1400 5.03 1,470 0600 3.74 544 

1000 11.06 6,310 1500 4.95 1,410 1200 3.67 502 

1100 11.44 6,690 1600 5.24 1,640 1800 3.56 436 

1200 11.82 7,070 1800 6.18 2,410 2400 3.48 390 

1300 12.13 7,380 2000 6.86 2,990 

2200 7.11 3,190 

2400 7.30 3,340

Total runoff, in inches 2.65

TABLE 4. -Site description and gage-height and discharge dataContinued

SITE 9. 03039000. Crooked Creek at Crooked Creek Dam, Pa.

Location.-Lat 40°43'13", long 79°30'42", Armstrong County, Hydrologic Unit 05010006, on 

the right bank 0.4 mi (0.6 km) downstream from Crooked Creek Dam, 3.5 mi (5.6 km) south 

of Ford City, and 6.7 mi (10.8 km) upstream from mouth. 

. Gage - Water-stage recorder. Datum of gage is 799.51 ft (243.691 m) NGVD of 1929. Prior to 

August 1, 1933, a nonrecording gage was at a site 2 mi (3 km) downstream, at a different 

datum. From July 31, 1933, to December 5, 1939, a nonrecording gage was at a site 1.5 mi 

(2.4 km) downstream, at a different datum. 

Remarks. -Flow has been completely regulated since 1940 by Crooked Creek Lake, 0.4 mi 

(0.6 km) upstream, and since 1968, by Keystone Lake; the combined capacity of the lakes is 

115,910 acre-ft (143 hm3 ).

Gage Dis- Gage Dis- Gage DisTime height charge Time height charge Time height charge 

(ft) (ft3 /s) (ft) (ft3/s) (ft) (ft3/s)

July 19: July 21: July 23: 

0600 123 99 0200 4.09 1,260 0600 7.51 4,010 

1200 123 99 0400 4.12 1,280 1200 7.44 3,940 

1800 124 101 0600 4.17 1,310 1800 7.36 3,860 

1900 1.24 101 0800 4.19 1,320 2400 7.28 3,780 

2000 1 33 120 1000 5.36 2,140 July 24: 

2100 131 115 1200 5.40 2,170 0600 7.19 3,690 

2200 128 109 1400 6.68 3,200 1200 7.07 3,570 

2300 129 111 1600 6.70 3,220 1800 6.97 3,470 

2400 1.29 111 1800 6.69 3,210 2400 6.85 3,350 

July 20- 2000 6.68 3,200 July 25: 

0600 1 29 111 2200 6.68 3,200 0600 6.71 3,230 

0800 131 115 2400 6.68 3,200 0900 6.63 3,160 

1000 2.41 474 July 22: 1000 4.76 1,720 

1200 242 478 0200 6.69 3,210 1100 4.83 1,770 

1400 245 490 0400 6.69 3,210 1200 4.74 1,720 

1600 391 1,160 0600 6.69 3,210 1300 3.79 1,090 

1800 399 1,200 0800 6.69 3,210 1400 3.77 1,080 

2000 401 1220 1000 6.69 3,210 1600 3.79 1,090 

2200 405 1240 1200 6.72 3,240 1800 3.81 1,100 

2400 409 1260 1300 7.62 4,120 2000 3.84 1,110 

1400 7.65 4,150 2200 3.87 1,130 

1600 7.64 4,140 2400 3.90 1,150 

1800 7.62 4,120 

2000 7.59 4,090 

2200 7.59 4,090 

2400 7.57 4,070

Total runoff, in inches _ 2 - 23

SITE 10. 03039200. Clear Run near Buckstown, Pa.

Location. -Lat 40°02'49", long 78°50°00", Somerset County, Hydrologic Unit 05010007, on 

the left bank at the downstream side of the bridge on State Highway 160, 0.8 mi (1.3 km) 

south of Reels Corners and 2.3 mi (3.7 km) southeast of Buckstown. 

Gage -Water-stage recorder, crest-stage gage, and concrete control. Datum of the gage is 

2,339.24 ft (713.00 m) NGVD of 1929. From July 6, 1960, to Aug. 31, 1964, a crest-stage 

gage was at a site 50 ft (15 m) upstream, at the same datum.

Gage Dis- Gage Dis- Gage DisTime- height charge Time height charge Time height charge 

(ft) (ft3 /s) (ft) (ft3/s) (ft) (ft3/s)

July 19: July 20: July 20: 

0100 2.18 0.51 0400 2.38 1.7 1400 3.20 66 

1200 2.18 .'51 0500 3.81 23 1600 3.06 50 

1800 2.17 .48 0530 5.03 366 1800 2.97 40 

2200 2.16 .45 0600 4.68 296 2000 2.91 33 

2300 2.31 1.1 0700 4.31 222 2200 2.86 28 

2400 227 88 0800 4.14 196 2400 2.82 24 

July 20- 0900 3.92 163 July 21: 

0100 229 .99 1000 3.68 129 0600 2.74 17 

0200 234 1.3 1100 3.53 108 1200 2.66 11 

0300 2.34 1.3 1200 3.41 91 1600 2.62 8.8

Total runoff, in inches ______________________ °-76

SITE 11. 03039910. Seese Run at Windber, Pa.

Location. -Lat 40°13'44", long 78°49'43", Somerset County, at the bridge on State Highway 

160 in Windber, 0.4 mi (0.6 km) upstream from the mouth. 

Gage. - Miscellaneous site.

SITE 12. 03039914. Paint Creek at Windber, Pa.

Location.-Lat 40°14'33", long 78°50'47", Somerset County, along State Highway 56, 0.4 mi 

(0.6 km) upstream from State Highway 601 near the northwest corporate boundary. 

Gage - Miscellaneous site.
TABLES 61

TABLE 4. -Site description and gage-height and discharge dataContinued

SITE 13. 03040000. Stoney Creek at Ferndale, Pa.

[NOTE: Gage heights and discharges are estimated beginning at 0800 hours on July 20] 

Location. -Lat 40°17'08", long 78°55'15", Cambria County, Hydrologic Unit 05010007, on the 

right bank 50 ft (15 m) upstream from the highway bridge at Ferndale, 0.4 mi (0.6 km) 

doownstream from Bens Creek, 1.2 mi (1.9 km) upstream from the Johnstown city limits, 

and 5.2 mi (8.4 km) upstream from the confluence with the Little Conemaugh River. 

Gage.- Water-stage recorder. Datum of the gage is 1,184.06 ft (360.901 m) NGVD of 1929. 

Prior to March 19, 1936, a nonrecording gage was at a site 3.5 mi (5.6 km) downstream, at a 

different datum. From December 8, 1938, to January 30, 1940, a nonrecording gage was at a 

site 50 ft (15 m) downstream, at the present datum. 

Remarks. Regulation is by mine pumpage and reservoirs and by diversion above the station; 

the four largest reservoirs have a combined capacity of 42,360 acre-ft (52.2 hm3 ).

Gage Dis- Gage Dis- Gage DisTime height charge Time height charge Time height charge 

(ft) (ft3/s) (ft) (ft'/s) (ft) (ft»/s)

July 19: July 20: July 21: 

0100 2.26 97 0600 18.27 38,800 0600 6.50 4,050 

0600 2.23 92 0700 23.21 48,000 1200 6.00 3,280 

1200 2.19 84 0800 21.50 45,500 1800 5.64 2,530 

1800 2.19 84 0900 20.10 43,000 2400 5.32 2,090 

1900 2.26 97 1000 18.80 40,200 July 22: 

2200 2.27 99 1100 17.40 36,300 1200 4.79 1,520 

2300 2.53 169 1200 16.10 32,300 2400 4.46 1,190 

2400 2.99 350 1400 13.30 22,600 July 23: 

July 20: 1600 10.70 14,100 1200 4.18 924 

0100 3.72 796 1800 9.15 9,710 2400 3.94 732 

0200 4.64 1,640 2000 8.20 7,430 

0300 5.07 2,070 2200 7.58 6,060 

0400 5.38 2,420 2400 7.20 5,300 

0500 8.99 9,330

Total runoff, in inches _ 1.98

SITE 14. 03040016. Sams Run at Geistown, Pa.

Location. - Lat 40°17'20", long 78°52'58", Cambria County, 0.4 mi (0.6 km) upstream from the 

corporate boundary at the State Highway 756 bridge in Geistown. 

Gage. - Miscellaneous site

SITE 15. 03040018. Sams Run at Lorain, Pa.

Location. - Lat 40°17'42", long 78°54'04", Cambria County, in an artificial channel between 

city residence numbers 369 to 375 along State Highway 756 in Lorain. 

Gage. - Miscellaneous site.

SITE 16. 03040095. North Branch Little Conemaugh River tributary 

near Ebensburg, Pa.

Location. - Lat 40°28'05", long 78°41'3r, Cambria County, at a dirt road crossing 0.1 m: (0.2

km) downstream from the Tong Club dam, 1.2 mi (1.9 km) upstream from the mouth, 2.0 mi 

(3.2 km) southeast of Ebensburg, and 2.1 mi (3.4 km) west of Munster. 

Gage. - Miscellaneous site.

SITE 17. 03040300. Little Conemaugh River at Summerhill, Pa.

Location. -Lat 40°22'19", long 78°46'00", Cambria County, at the State Highway 53 bridge 

southwest of Summerhill, 500 ft (150 m) upstream from the Conrail bridge, 0.6 mi (1.0 km) 

downstream from Laurel Run, and 1.5 mi (2.4 km) above South Fork Little Conemaugh 

River. 

Gage. - Miscellaneous site.

SITE 18. 03040420. Otto Run at Salix, Pa.

Location, - Lat 40° 17'43", long 78°45'30", Cambria County, at a bridge on a paved road 0.5 mi 

(0.8 km) southeast of Salix and 300 feet (90 m) downstream from a small reservoir. 

Gage. -Miscellaneous site.

SITE 19 03040430. South Fork Little Conemaugh River tributary at 

St. Michael, Pa.

Location. - Lat 40°19'35", long 78°46'23", Cambria County, 400 ft (120 m) downstream from 

a reservoir, 0.6 mi (1.0 km) south of Saint Michael, 0.7 mi (1.1 km) upstream of mouth, and 

2.8 mi (4.5 km) southeast of South Fork. 

Gage. -Miscellaneous site.

SITE 20. 03040500. South Fork Little Conemaugh River at 

Fishertown, Pa.

Location- Lat 40°20/54", long 78°46'32", Cambria County, at the old South Fork Reservoir 

dam site at Fishertown and 0.1 mi (0.2 km) upstream from U.S. Highway 219. 

Gage. -Miscellaneous site.

SITE 21. 03040503. Sandy Run above Sandy Run Reservoir near 

St. Michael, Pa.

Location. -Lat 40°19'30", long 78°48'09", Cambria County, 0.2 mi (0.3 km) upstream from 

Sandy Run Reservoir and 1.8 mi (2.9 km) southwest of St. Michael. 

Gage. - Miscellaneous site.

TABLE 4. -Site description and gage-height and discharge dataContinued

SITE 22. 03040505. Sandy Run below Sandy Run Reservoir at 

St. Michael, Pa.

Location. -Lat 40°20'10", long 78°47'21", Cambria County, just upstream from the U.S. 

Highway 219 bridge, 0.9 mi (1.4 km) west of St. Michael, and 0.9 mi (1.4 km) northeast of 

Sandy Run Dam. 

Gage. - Miscellaneous site.

SITE 23. 03041000. Little Conemaugh River at East Conemaugh, Pa.

Location. - Lat 40°20'37", long 78°53'07", Cambria County, Hydrologic Unit 05010007, on the 

right bank 100 ft (30 m) downstream from the bridge on State Highway 271 at East Conemaugh, 0.3 mi (0.5 km) downstream from Clapboard Run, and 2.5 mi (4.0 km) upstream from 

the confluence with Stony Creek. 

Gage. -Water-stage recorder. Datum of gage is 1,208.29 ft (368.287 m) NGVD of 1929. Prior 

to February 1, 1940, a nonrecording gage was at a site 100 ft (30 m) upstream, at the same 

datum. 

Remarks. - Flow is regulated by reservoirs and by diversion above the station; the two most 

effective reservoirs have a combined capacity of 5,640 acre-ft (6.95 hm3 ).

Gage Dis- Gage Dis- Gage DisTime height charge Time height charge Time height charge 

(ft) (ft3 /s) (ft) (ft3/s) (ft) (ft3/s)

July 19: July 20: July 22: 

1800 1.66 140 1100 10.21 15,500 0600 3.31 2,820 

2100 1.66 140 1200 9.39 13,800 1200 2.95 2,280 

2200 1.87 191 1400 8.45 11,900 1800 2.60 1,790 

2300 2.62 542 1600 7.63 10,300 2400 2.35 1,460 

2400 3.65 1,340 1800 7.16 9,400 July 23: 

July 20: 2000 6.80 8,740 0600 2.20 1,260 

0100 3.75 1,460 2200 6.49 8,180 1200 2.03 1,040 

0200 5.77 4,240 2400 6.16 7,590 1800 1.87 856 

0300 9.27 13,000 July 21: 2400 1.92 904 

0400 10.60 16,300 0300 5.84 7,010 July 24: 

0500 12.35 20,400 0600 5.58 6,540 0600 1.72 664 

0600 18.09 37,100 0900 5.37 6,170 1200 1.68 618 

0615 18.85 40,000 1200 5.19 5,840 1800 1.66 596 

0700 17.45 34,700 1500 4.82 5,210 2400 1.64 574 

0800 15.12 27,400 1800 3.77 3,530 

0900 12.86 21,700 2100 3.64 3,360 

1000 11.37 18,100 2200 3.67 3,420 

2400 3.64 3,360

Total runoff, in inches _ __ 4.70

SITE 24. 03041030. Elk Run at Morrellville, Pa.

Location. -Lat 40°20'33", long 78°56'39", Cambria County, just upstream from Fairview Ave. 

and St. Columbus Cemetery in Morrellville. 

Gage. - Miscellaneous site.

SITE 25. 03041038. Laurel Run at Chickaree, Pa.

Location. -Lat 40°26'54", long 78°53'09", Cambria County, at a culvert on the road between 

Chickaree and Vintondale, 0.25 mi (0.40 km) northwest of Chickaree. 

Gage. - Miscellaneous site.

SITE 26. 03041039. Laurel Run above Laurel Run Reservoir near 

Cooper sdale, Pa.

Location. - Lat 40°23'16", long 78°54'34", Cambria County, at the inlet to Laurel Run Reservoir, 1,900 ft (580 m) upstream from the dam and 2.5 mi (4.0 km) north of Coopersdale. 

Gage. - Miscellaneous site.

SITE 27. 03041040. Red Run near Coopersdale, Pa.

Location. -Lat 40°22'57", long 78°55'09", Cambria County, at the mouth, 0.3 mi (0.5 km) 

southwest of Laurel Run Dam and 2 mi (3 km) northeast of Coopersdale. 

Gage. - Miscellaneous site.

SITE 28. 03041043. Laurel Run below Laurel Run Reservoir near 

Coopersdale, Pa.

Location. - Lat 40°22'45", long 78°55'07", Cambria County, 300 ft (90 m) downstream from the 

Cooper Ave. bridge, 0.9 mi (1.4 km) upstream from Wildcat Run, 1.6 mi (2.6 km) above the 

mouth, and 1.5 mi (2.4 km) northeast of Coopersdale. 

Gage. - Miscellaneous site.

SITE 29. 03041046. Wildcat Run at Coopersdale, Pa.

Location. -Lat 40°22'10", long 78°55'58", Cambria County, at the mouth, 1.0 mi (1.6 km) north 

of Coopersdale and 300 ft (90 m) downstream from Cooper Ave. 

Gage. - Miscellaneous site.
62 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

TABLE 4. -Site description and gage-height and discharge dataContinued

SITE 30. 03041500. Conemaugh River at Seward, Pa.

Location.-Lat 40°25'09", long 79°01'35", Westmoreland County, Hydrologic Unit 

05010007, on the left bank at the upstream side of a bridge on State Highway 56 at Seward, 

2.0 mi (3.2 km) downstream from Findley Run and 9 mi (14 km) northwest of Johnstown.

Gage. - Water-stage recorder. Datum of the gage is 1,076.01 ft (327.968 m) NGVD of 1929.

Remarks. Flow is regulated by steel mills and by reservoirs above the station; the eight most 

effective reservoirs have a combined capacity of 51,850 acre-ft (63.9 hm3

Time

July 19:

0100

0600

1200

1800

2200

2300

2400

July 20:

0100

0200

0300

0400

0500

0600

0700

0800

0900

1000

1100

Gage

height

(ft)

2.47

2.42

2.37

2.34

2.38

2.55

3.61

6.16

6.83

7.55

12.76

22.09

24.40

25.65

27.06

25.85

24.75

23.74

Total runoff, in ir

Discharge

(fWs)

529

494

459

438

466

585

1,690

6,250

7,730

9,440

23,100

68,300

Time

July 20:

1200

1300

1400

1500

1600

1700

1800

1900

2000

2100

2200

2300

2400

Gage

height

(ft)

21.73

19.90

18.23

16.74

14.70

13.29

12.52

11.88

11.38

10.98

10.60

10.30

9.98

Discharge

(ft"/S)

65,500

54,500

44,500

37,300

29,300

24,400

22,100

18,800

17,500

15,9(10

15,200

13,900

12,900

86,600 July 21:

98,000

115,000

99,500

88,800

80,100

iches

0200

0400

0600

0800

1000

9.48

9.08

8.80

8.46

8.20

10,200

9,990

9,560

8,260

7,660

Time

July 21:

1200

1400

1600

1800

2000

2200

2400

July 22:

0600

1200

1800

2400

July 23:

0600

1200

1800

2400

Gage

height

(ft)

8.02

7.86

7.72

7.78

7.72

7.72

7.85

7.48

7.13

6.82

6.52

6.28

6.12

5.92

5.78

Discharge

(ft3 /s)

7,260

6,690

6,380

6.520

6,380

6,380

6,670

5,860

5,160

4,540

3,940

3,340

3,060

2,720

2,660

3.10

SITE 31 03042000. Blacklick Creek at Josephine, Pa.

Location. -Lat 40°28'24", long 79°11'01", Indiana County, Hydrologic Unit 05010007, on the 

right bank on the upstream side of an old concrete dam at Josephine, 0.9 mi (1.4 km) 

upstream from Two Lick Creek and 5 mi (8 km) northeast of Blairsville. A water-quality 

sampling site is 820 ft (250 m) downstream.

Gage. - Water-stage recorder and crest-stage gage. Datum of the gage is 975.82 ft (297.430 m) 

NGVD, datum of 1912. Prior to August 25, 1953, a nonrecording gage was at the same site 

and datum.

Remarks.-Some regulation at low flow is by mine pumpage above the station.

Time

July 19:

0100

0600

1200

1800

2100

2200

2300

2400

July 20:

0100

0200

0300

0400

0500

0600

0700

0800

0830

0900

1000

1100

Total

Gage

height

(ft)

4.06

3.84

3.62

3.59

3.63

4.16

6.46

10.87

11.90

11.79

11.90

12.55

14.45

16.15

17.70

19.15

19.89

19.55

19.00

18.30

runoff, in i

Discharge

(ft3/s)

251

180

118

111

121

289

2,280

10,600

13,200

12,900

13.200

15,000

21,100

27,100

33,800

41,300

45,700

42,800

39,500

36,000

nches

Time

July 20:

1200

1300

1400

1500

1600

1700

1800

1900

2000

2100

2200

2300

2400

July 21:

0200

0400

0600

0800

1000

1200

1800

Gage

height

(ft)

17.94

17.34

16.29

14.55

13.65

12.50

11.80

11.05

10.35

9.65

9.05

8.75

8.50

8.40

7.93

7.68

7.47

7.29

7.13

6.80

Discharge

(ft3/s)

34,200

31,200

26,300

19,300

16,300

12,700

10,800

8,780

7,260

5,860

4,730

4,240

3,840

3,700

3,040

2,720

2,460

2,250

2,060

1,700

Time

July 21:

2200

2300

2400

July 22:

0100

0200

0300

0800

1200

1800

2400

July 23:

0600

1200

1800

2400

July 24:

0600

1200

1800

2400

Gage

height

(ft)

6.70

6.76

6.91

7.01

7.00

6.97

6.83

6.47

6.19

5.93

5.74

5.62

5.47

5.36

5.25

5.19

5.14

5.14

Discharge

(ft3/s)

1,600

1,660

1,810

1,910

1,900

1,870

1,730

1,380

1,150

944

804

732

642

576

515

485

460

460

4.93

SITE 32. 03042170. Stoney Run at Indiana, Pa.

Location.-Lat 40°36'31", long 79°09'49", Indiana County, at the southwest edge of Indiana,

300 ft (90 m) west of U.S. Highway 119 and 0.1 mi (0.2 km) below Marsh Run. 

Gage. -Crest-stage.

TABLE 4. -Site description and gage-height and discharge dataContinued

SITE 33. 03042180. Two Lick Creek near Homer City, Pa.

Location.-Lat 40°33'51", long 79°09'42", Indiana County, at a bridge on U.S. Highway 219,

4.2 mi (6.8 km) south of Indiana. 

Gage. - Miscellaneous site.________________________________________

SITE 34. 03042198. Little Yellow Creek tributary at Strongstown, Pa.

Location. -Lat 40°33'33", long 78°56'19", Indiana County, at a highway culvert on U.S 

Highway 422, 2,000 ft (610 m) upstream from the mouth, 0.8 mi (1.3 km) northwest of 

Strongstown, and 1.5 mi (2.4 km) southeast of Nolo.

Gage. Miscellaneous site.________________________________________

SITE 35. 03042200. Little Yellow Creek near Strongstown, Pa.

Location.-Lat 40°33'45", long 78°56'44", Indiana County, Hydrologic Unit 05010007, on the 

right bank 100 ft (30 m) downstream from a concrete box culvert cm U.S. Highway 422, 1.4 

mi (2.3 km) northwest of Strongstown, 6 mi (10 km) upstream from the mouth, and 11 mi (18 

km) southeast of Indiana.

Gage. - Water-stage recorder and crest-stage gage. Datum of the gage is 1,586.83 ft (483.666 

m) NGVD. From August 25, 1959 to August 31, 1960, a low-flow gage and, from November 

6, 1959 to August 31, 1960, a crest-stage gage were at a site 100 ft (30 m) upstream, at the 

same datum. ______

Gage

height

(ft)

Discharge 

(fWs)

Time

Gage

height

(ft)

Discharge

(fWs)

Time

Gage Disheight charge

(ft) (ft-Vs)

4.15

4.05

3.96

3.88

3.84

3.74

3.69

3.65

120

103

93

85

68

56

47

39

Total runoff, in inches

SITE 36. 03042280. Yellow Creek near Homer City, Pa.

Location.-Lat 40°34'18", long 79°06'13", Indiana County, Hydrologic Unit 05010007, on the 

left bank, 0.3 mi (0.5 km) upstream from the Central Indiana County Water Authority dam 

and 3.5 mi (5.6 km) northeast of Homer City.

Gnge . - Water-stage recorder. Altitude of the gage is 1,140 ft (347 m), from a topographic 

map.

Remarks.-Flows are not adjusted for the effect of Ferrier Run following a flood-induced 

break in the Ferrier Run diversion project. Ferrier Run now enters Yellow Creek between 

the dam (flow measurement site) and the gaging station, instead of downstream from the 

dam. ____

Time

Gage 

height

(ft)

Discharge

(ft-Vs)

Time

Gage 

height

(ft)

Discharge

(ft3 /s)

Time

Gage

height 

(ft)

Discharge

(ftVs)

12.60

12.25

12.02

11.61

11.28

10.85

10.01

9.17

8.59

8.11

7.70

7.39

15,000

14,000

13,400

12,300

11,500

10,500

8,620

6,840

5,760

4,980

4,320

3,850

July 21: 

0200 

0400 

0600 

1200 

2400

July 22: 

1200 

2400

July 23: 

1200 

2400

July 24: 

1200 

2400

Total runoff, in inches _________________________________ 7.69 

SITE 37. 03042282. Ferrier Run near Homer City, Pa.

Location.-Lat 40°34'18", long 79°0613", Indiana County, at an artificial channel near the 

mouth near Yellow Creek near the Homer City gaging station, 3.5 mi (5.6 km) northeast of 

Homer City and 4.5 mi (7.2 km) southeast of Indiana.

Gage. - Miscellaneous site.
TABLES 63

TABLE 4. -Site description and gage-height and discharge data 

Continued

SITE 38. 03042500. Two Lick Creek at Graceton, Pa.

NOTE: [Gage heights and discharges estimated from 1600 hours on July 20 until 0600 hours 

on July 21.] 

Location -Lat 40°31'02", long 79°10'19", Indiana County, Hydrologic Unit 05010007, on the 

right bank 0.8 mi (1.3 km) upstream from a highway bridge on the road leading west from 

Graceton, 1.1 mi (1.8 km) downstream from Tearing Run, 1.5 mi (2.4 km) upstream from 

Cherry Run, and 8 mi (13 km) northeast of Blairsville. A water-quality sampling site is at a 

bridge 0.8 mi (1.3 km) downstream. 

Gage.- Water-stage recorder. Datum of the gage is 981.63 ft (299.201 m) NGVD of 1929. 

Remarks. -Diurnal fluctuation is caused by mine pumpage and by a sewage-disposal plant 

above the station. Flow has been regulated since December 1968 by Two Lick Creek Reservoir, 10 mi (16 km) upstream, which has a capacity of 16,240 acre-ft (20.0 hm3 ), and since 

July 1971, by Yellow Creek Lake, 11 mi (18 km) upstream.

Gage Dis- Gage Dis- Gage DisTime height charge Time height charge Time height charge 

(ft) (ft3/s) (ft) (ft3/s) (ft) (ft3/s)

July 19: July 20: July 21: 

0100 2.45 160 0800 17.75 29,500 1800 7.50 3.400 

0600 2.42 151 0900 18.30 31,000 1900 7.71 3.610 

1200 2.43 154 0930 18.65 32,000 2000 7.72 3,620 

1400 2.46 163 1000 18.33 28,500 2100 7.55 3,450 

1600 2.52 181 1100 18.08 27,000 2200 7.39 3,290 

1700 2.55 190 1200 17.60 24,000 2400 7.16 3,080 

1800 2.56 193 1400 17.00 21,600 July 22: 

1900 2.53 184 1600 15.80 17,800 0600 6.77 2,720 

2000 2.97 320 1800 14.40 13,900 1200 6.50 2,480 

2100 5.53 1,700 2000 12.90 10,700 1800 6.25 2,280 

2200 8.55 4,460 2200 11.40 8,200 2400 4.15 795 

2300 10.12 6,540 2400 10.30 6,650 July 23: 

2400 10.60 7,500 July 21: 0600 3.93 685 

July 20: 0200 9.50 5,520 1200 3.70 590 

0100 10.28 6,860 0400 9.08 5,050 1800 3.54 526 

0200 10.34 6,980 0600 8.69 4,620 2400 3.40 470 

0300 11.55 9,680 0700 8.50 4,410 July 24: 

0400 12.68 12,800 1200 7.73 3,630 0600 3.31 434 

0500 13.79 16,200 1400 7.47 3,370 1200 3.23 402 

0600 15.16 20,500 1600 7.25 3,160 1800 3.14 366 

0700 16.78 26,300 1700 7.23 3.140 2400 3.08 343

SITE 39. 03044000. Conemaugh River at Tunnelton, Pa.

Location. -La.1 40°27'16", long 79°23'28", Indiana County, Hydrologic Unit 05010007, on the 

right bank at the downstream side of a highway bridge at Tunnelton, 0.9 mi (1.4 km) 

downstream from Boatyard Run, 2.0 mi (3.2 km) downstream from Conemaugh River Dam, 

3.8 mi (6.1 km) southeast of Saltsburg, and 5.5 mi (8.9 km) upstream from the confluence 

with Loyalhanna Creek. 

Gage. - Water-stage recorder. Datum of the gage is 844.64 ft (257.446 m) NGVD of 1929. Prior 

to October 1, 1952, a nonrecording gage was at the same site and datum. 

Remarks. - Flow has been regulated since 1971 by Yellow Creek Lake; since 1952, by Conemaugh River Lake, 2 mi (3 km) upstream, and by reservoirs above the station, the nine most 

effective of which have a combined capacity of 68,090 acre-ft (840.0 hm3 ). Evaporation from 

the operation of the Homer City and Conemaugh generating stations, which began during 

1969 and 1970, respectively, can amount to as much as 45 ft3 /s (1.3 m3 /s).

Gage Dis- Gage Dis- Gage DisTime height charge Time height charge Time height charge 

(ft) (ft3 /s) (ft) (ft3 /s) (ft) (fWs)

July 19: July 21: July 24: 

1200 3.62 1,510 2200 11.89 23,300 0300 11.34 21,400 

1800 3.61 1,500 2300 11.98 23,600 0600 11.29 21,200 

2400 3.63 1,530 2400 11.98 23,600 0900 11.23 21,000 

July 20: July 22: 1000 10.31 18,100 

0300 3.75 1,720 0600 11.97 23,600 1100 10.09 17,400 

0600 3.88 1,950 0900 11.94 23,500 1200 10.05 17,300 

0900 4.01 2,870 1200 11.91 23,400 1500 10.00 17,100 

1200 4.56 3,170 1500 11.87 23,300 1800 9.96 17,000 

1500 5.99 6,140 1800 11.84 23,100 2400 9.86 16,700 

1800 7.34 9,450 2100 11.81 23,000 July 25: 

2100 8.62 12,800 2400 11.77 22,900 0600 9.76 16,400 

2400 9.15 14,500 July 23: 1200 9.72 16,200 

July 21: 0300 11.73 22,700 1300 8.78 13,300 

0300 9.51 15,500 0600 11.69 22,600 1400 8.58 12,700 

0600 9.99 17,100 0900 11.64 22,400 1500 7.60 10,100 

0900 10.24 17,800 1200 11.59 22,300 1600 7.36 9,500 

1200 10.35 18,200 1500 11.54 22,100 1800 7.33 9,420 

1500 10.77 19,500 1800 11.50 22,000 2000 7.33 9,420 

1800 11.27 21,200 2100 11.44 21,800 2200 7.32 9,400 

2100 11.62 22,400 2400 11.39 21,600 2400 7.32 9,400

Total runoff, in inches 2.82

SITE 40. 01540600. West Branch Susquehanna River at 

Barnesboro, Pa.

Location. - Lat 40°40'10", long 78°47'29", Cambria County, at the 22nd St. bridge in 

Barnesboro. 

Gage. -Miscellaneous site.

TABLE 4. -Site description and gage-height and discharge dataContinued

SITE 41. 01540650. West Branch Susquehanna River at 

Cherry Tree, Pa.

Location. - Lat 40°43'34", long 78°48'20", Indiana County, at State Highway bridge 5H580 in 

Cherry Tree, 200 ft (60 m) downstream from Cush Cushion Creek. 

Gage. Miscellaneous site.

SITE 42. 01541000. West Branch Susquehanna River at Bower, Pa.

Location. -Lat 40°53'49", long 78°40'38", Clearfleld County, Hydrologic Unit 02050201, on 

the right bank at the downstream side of the highway bridge at Bower, 4.6 mi (7.4 km) 

downstream from Chest Creek and Mahaffey. 

Gage. -Water-stage recorder. Datum of the gage is 1,207.14 ft (367.936 m) NGVD of 1929. 

Prior to October 17, 1929, a nonrecording gage was at the same site and datum.

Gage Dis- Gage Dis- Gage DisTime height charge Time height charge Time height charge 

(ft) (ft3/s) (ft) (ft3/s) (ft) (ft3/s)

July 19: July 20 July 21: 

0600 5.24 313 0500 15.50 17,000 2100 10.10 4,740 

1200 5.14 278 0600 15.18 16,000 2200 10.27 5,000 

1300 5.12 271 0700 14.98 15,400 2300 10.23 4,940 

1400 5.13 274 0800 14.85 15,100 2400 10.15 4,820 

1500 5.12 271 0900 14.82 15,000 July 22: 

1800 5.13 274 1200 14.83 15,000 0300 9.88 4,420 

1900 5.16 285 1500 14.63 14,400 0600 9.39 3,740 

2000 5.37 362 1800 14.52 14,100 0900 8.93 3,150 

2100 5.65 474 2100 14.44 13,900 1200 8.64 2,800 

2200 6.35 832 2400 14.32 13,600 1800 8.27 2,400 

2300 9.60 4,030 July 21: 2400 7.84 1,980 

2400 13.00 10,200 0300 14.02 12,700 July 23: 

July 20: 0600 13.10 10,400 1200 7.24 1,450 

0100 16.12 18,900 0900 11.40 6,850 2400 6.84 1,150 

0130 16.23 19,200 1200 10.35 5,120 July 24: 

0200 16.15 19,000 1500 9.77 4,270 1200 6.55 958 

0300 15.98 18,500 1800 9.46 3,830 2400 6.30 802 

0400 15.80 17,900 1900 9.55 3,960 

2000 9.85 4,380

SITE 43 01541200. West Branch Susquehanna River at 

Curwensville, Pa.

Location. -Lat 40°57'41", long 78° 3110", Clearfield County, Hydrologic Unit 02050201, on 

the left bank 30 ft (9 m) downstream from the bridge on State Highway 453, 0.85 mi (1.37 

km) downstream from Curwensville Lake, 1.1 mi (1.8 km) south of Curwensville, and 1.8 mi 

(2.9 km) upstream from Anderson Creek. A water-quality sampling site at bridge is 30 ft (9 

m) upstream.. 

Gage.- Water-stage recorder. Datum of the gage is 1,124.52 ft (342.754 m) NGVD of 1929. 

Prior to August 24, 1956, a nonrecording gage and a crest-stage gage were 30 ft (9 m) 

upstream at same datum. 

Remarks. - Flow is regulated by Curwensville Lake, 0.85 mi (1.37 km) upstream.

SITE 44. 01541308. Bradley Run near Ashville, Pa.

right bank 200 ft (60 m) downstream from the bridge on State Highway 53 at Syberton, 0.2 

mi (0.3 km) upstream from the mouth and 4.5 mi (7.2 km) southwest of Ashville. 

Gage. - Water-stage recorder. The altitude of the gage is 1,770 ft (539 m), from a topographic 

map.

SITE 45. 01541321. Brubaker Run at Dean, Pa.

Location. - Lat 40°37'20", long 78°30'12", Cambria County, at a culvert on State Highway 53 

at Dean, 0.1 mi (0.2 km) upstream from the mouth. 

Gage. -Miscellaneous site.

SITE 46. 01541365. North Witmer Run at Irvona, Pa.

Location. - Lat 40°46'12", long 78°32'59", Clearfield County at the mouth at Irvona. 

Gage. ~ Miscellaneous site.

SITE 47. 01541500. Clearfield Creek at Dimeling, Pa.

Location-Lat 40°58'18", long 78°24'22", Clearfield County, Hydrologic Unit 02050201, on the 

right bank at the downstream side of the highway bridge at Dimeling, 600 ft (180 m) 

downstream from Little Clearfield Creek, and 4 mi (6 km) southeast of Clearfield. 

Gage. -Water-stage recorder. Datum of the gage is 1,146.08 ft (349.325 m) NGVD of 1929. 

Prior to October 17, 1928, a nonrecording gage and from October 17, 1928, to October 25, 

1967, a water-stage recorder were at a site 200 ft (60 m) upstream, all at the same datum. 

Remarks. - Flow regulated by Glendale Lake, about 25 mi (40 km) upstream.

SITE 48. 01542000. Moshannon Creek at Osceola Mills, Pa.

Location. -Lat 40°50'58", long 78°16'05", Clearfleld County, Hydrologic Unit 02050201, on 

the left bank 10 ft (3.0 m) upstream from the CONRAIL bridge at Osceola Mills and 0.1 mi 

(0.2 km) downstream from Trout Run. 

Gage.- Water-stage recorder. Datum of the gage is 1,446.98 ft (441.040 m) NGVD of 1929.

SITE 49, 01556000. Frankstown Branch Juniata River at 

Williamsburg, Pa.

Location. -Lat 40°27'47", long 78°12'00", Blair County, Hydrologic Unit 02050302, on the left 

bank 10 ft (3 m) downstream from highway bridge at Williamsburg and 2.5 mi (4.0 km) 

upstream from Clover Creek. 

Gage. -Water-stage recorder. Datum of gage is 831.78 ft (253.53 m) NGVD of 1929 (Penn 

Central Railroad bench mark). Prior to August 14, 1928, a nonrecording gage was at the 

same site and datum. 

Remarks.- Regulation at low flow by a mill above the station.
64 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

TABLE 4. -Site description and gage-height and discharge dataContinued

TABLE 5. -Floodmark data

[Elevations of selected floodmarks are provided in this table for defining flood profiles on 

reaches of 27 streams in the Mahoning Creek and Conemaugh River basins. Each elevation 

is referenced by a stream mile, which is the distance upstream from its mouth. The stream

SITE 50. 01556400. Sandy Run near Bellwood, Pa.

Location. -Lat 40°33'47", long 78°20'35", Blair County, at a bridge on a private road 0.6 mi 

(1.0 km) above the mouth and 2.5 mi (4.0 km) south of Bellwood.

Gage. - Crest-stage.

SITE 51. 01556500. Little Juniata River at Tipton, Pa.

bridge on State Highway 220 and 150 ft (46 m) downstream from Tipton Run.

NGVD of 1929.

SITE 52. 01557100. Schell Run at Tyrone,Pa.

Location. -Lat 40°40'00", long 78°15'00", Blair County, 0.2 mi (0.3 km) above U.S. 

Highway 220 between 5th St. and Shippen St. in Tyrone. 

Gage. - Water-stage recorder. Datum of the gage is 919.11 ft (280.14 m) NGVD of 1929.

SITE 53. 01557500. Bald Eagle Creek at Tyrone, Pa.

Location. -Lat 40°41'01", long 78°14'02", Blair County, Hydrologic Unit 02050302, on the left 

bank 0.2 mi (0.3 km) upstream from the plant of the West Virginia Pulp and Paper Co. at 

Tyrone, 0.2 mi (0.3 km) upstream from Laurel Run, and 1.3 mi (2.1 km) upstream from the 

mouth.

Gaffe. -Water-stage recorder. Datum of the gage is 921.80 ft (280.965 m) NGVD of 1929. 

From October 1, 1944 to November 15, 1950, a water-stage recorder and, from November 

16, 1950 to November 30, 1952, a nonrecording gage were at a site 0.5 mi (0.8 km) 

downstream, at a datum 17.99 ft (5.483 m) lower.

SITE 54. 01558000. Little Juniata River at Spruce Creek, Pa.

the right bank 150 ft (46 m) downstream from the CONRAIL bridge, 0.5 mi (0.8 km) northwest of village of Spruce Creek, and 0.5 mi (0.8 km) upstream from Spruce Creek. A waterquality sampling site is 0.4 mi (0.6 km) downstream.

Gage. - Water-stage recorder. Datum of the gage is 751.15 ft (228.951 m) NGVD of 1929.

SITE 55. 01559700. Buffalo Run tributary near Manns Choice, Pa.

left downstream end of the bridge on State Highway 96, 2,000 ft (610 m) upstream from the 

mouth, 2.3 mi (3.7 km) south of Manns Choice, and 11 mi (18 km) southwest of Bedford.

Gage. - Water-stage recorder and crest-stage gage. The altitude of the gage is 1 ,230 ft (375 m), 

from a topographic map.

Gage Dis- Gage Dis- Gage DisTime height charge Time height charge Time height charge 

(ft) (ft3 /s) (ft) (ftVs) (ft) (fts/s)

July 19: July 20: July 21: 

1200 0.39 0.34 0800 2.02 156 1200 0.69 14 

1800 .38 .28 0900 1.66 102 1700 .64 11 

2400 .48 .77 1000 1.37 67 2000 .69 14 

July 20: 1100 1.23 53 2400 .65 12 

0300 2.85 326 1200 1.15 45 July 22: 

0400 2.73 298 1500 .96 30 1200 .59 8.6 

0500 3.47 495 1800 .85 23 2400 .55 6.9 

0600 3.68 560 2100 .80 20 July 23: 

0620 5.12 1,120 2400 .77 18 1200 .52 5.7 

0700 2.74 300 2400 .49 4.6

Total runoff, in inches 1 09

SITE 56. 01560000. Dunning Creek at Belden, Pa.

Location. -L&t 40°04'18", long 78°29'34", Bedford County, Hydrologic Unit 02050303, on the 

left bank 10 ft (3 m) upstream from a highway bridge, 0.8 mi (1.3 km) southeast of Belden, 

3.8 mi (6.1 km) north of Bedford, and 4.3 mi (6.9 km) above the mouth. 

Gaffe. - Water-stage recorder. Datum of the gage is 1,051.16 ft (320.394 m) NGVD of 1929.

Gage Dis- Gage Dis- Gage DisTime height charge Time height charge Time height charge 

(ft) (fts/s) (ft) (ftVs) (ft) (ft3/s)

July 19: July 20: July 21: 

1200 1.33 21 1100 13.84 17,500 1800 4.07 944 

1800 1.35 23 1115 14.15 19,400 2100 4.04 934 

2100 1.35 23 1130 13.91 18,000 2400 4.54 1,110 

2400 1.47 39 1200 13.83 17,500 July 22: 

July 20: 1300 13.75 17,000 0100 4.63 1,110 

0100 1.66 71 1700 12.35 10,900 0300 4.45 1,040 

0200 2.02 157 1800 11.99 9,770 0600 3.90 840 

0300 3.59 756 2100 10.83 6,470 0900 3.61 724 

0400 6.47 1,790 2400 9.79 4,520 1200 3.44 648 

0500 8.59 3,190 July 21: 2400 2.95 440 

0600 9.33 3,940 0300 8.43 3,050 July 23: 

0700 10.30 5,350 0600 6.48 1,790 1200 2.75 328 

0800 11.34 7,820 0900 5.27 1,330 2400 2.56 261 

0900 12.57 11,700 1200 4.71 1,160 July 24: 

1000 13.53 15,800 1500 4.32 1,030 1200 2.46 228 

2400 2.38 204

SITE 57. 01600700. Little Wills Creek at Bard, Pa.

Location. -Lat 39°55'35", long 78°39'40", Bedford County, at the bridge on State Highway 

96 at Bard.

Gaffe. -Crest-stage. Datum of the gage is 1,264.2 ft (385.3 m) NGVD of 1929.

bank on which the floodmarks were located is given for many sites and is designated as right 

(R) or left (L) bank (determined as if one were facing downstream). Unless otherwise noted, 

the data in this table were furnished by the U.S. Army Corps of Engineers (1977)]

Elevation in 

Stream feet above 

Stream and location mile NGVD

Mahoning Creek

North Point, at highway bridge 36.93 1,156.94

Hamilton (R) 40.95 1,174.2

At highway bridge 41.03 1,174.65

Valier, at highway bridge 43.63 1,184.92

At highway bridge between Valier and 

Fordham 45.22 1,194.32

Sportsburg(R) 50.09 1,216.5

Punxsutawney, at U.S. Geological 

Survey gaging station (R) 51.28 1,222.44

Railroad Bridge 52.70 1,229.38

#114 Water St. (R) 52.99 1,231.0

Punxsutawney (R) 53.07 1,230.40

At U.S. Highway 119 bridge 54.06 1,231.17

At Mahoning St. bridge 54.77 1,232.56

Cloe, at highway bridge 57.48 1,252.0

Bells Mills, at highway bridge 58.94 1,263.19

At highway bridge 59.88 1,270.88

At railroad bridge 60.63 1,275.70

Big Run, at Mill St. bridge 62.57 1,284.18

McCardy Rd. bridge 63.52 1,290.07

Stump Creek

At State Highway 410 bridge _________ 1.48 1,307.9 

At road bridge near Cramer 2.71 1,312.3

Cramer, downstream from State Highway 952 bridge (L) 4.00 1,322.14

Upstream from State Highway 952 

bridge (L) 4.03 1,323.41

Sykesville, at road bridge 6.09 1,335.8

Park St. bridge 7.05 1,341.97

Bridge at confluence of Sugarcamp 

Run 7.30 1,345.1

Stanley, at road bridge 9.16 1,365.7

Conemaugh River

Blairsville, at old U.S. Highway 22 bridge __ 20.10 958.8 

State Highway 217 bridge 21.45 958.6

Strangford, at mouth of Toms Run (L) 24.40 961.81

Robinson, downstream side of State 

Highway 259 bridge (R) __________ 30.13 1,024.8 

Upstream side of State Highway 259 

bridge (R) 30.13 1,028.1

Bolivar RD #1 (L) 32.34 1,042.74

At downstream side of railroad bridge (L) _ 32.35 1,045.5 

At upstream side of railroad bridge (L) 32.35 1.048.4

Along legislative Route 32008 at Crawford Road 34.43 1,060.6

New Florence, at downstream side of 

railroad bridge (L) 36.09 1,067.0

At upstream side of railroad bridge (L) 36.09 1,068.7

Huff, at small tributary (R) 37.59 1,073.23

New Florence, at highway bridge 37.68 1,072.2

At #209 9th St. (L) 38.01 1,076.5

At Seward Generating Plant, pump 

house (R) 39.23 1,082.83

Robindale (R) 41.00 1,093.0

Seward, at Penelec generating plant (R) ___ 41.82 1,097.96
TABLES 65

TABLE 5.-Floodmark data-Continued

Stream and location

Stream 

mile

Elevation in 

feet above 

NGVD

Conemaugh River Continued

Seward, at U.S. Geological Survey gaging 

station at upstream side of State 

Highway 56 bridge (L)

At brick house just upstream 

from State Highway 56 bridge (L)

Johnstown, at downstream side of railroad 

bridge at north corporate boundary

Upstream side of railroad bridge

Bethlehem Steel Co.'s wire mill (R)

State Highway 403 bridge ______________ 

Church at corner of 8th Ave and 

Chestnut St. (L)

Downstream side of Fourth St.

Upstream side of Fourth St. 

bridge

Church at corner of Fourth Ave. and 

Chestnut St. (T,)

Footbridge at Roosevelt Blvd. and 

McConaughy St.

Along State Highway 56 at railroad 

overpass (L)

42.85 

42.89

49.32 

49.32 

50.35 

50.71

51.40 

51.69 

51.69 

51.70 

52.07 

52.33

1,103.1 

1,104.20

1,154.6 

1,156.9 

1,158.74 

1,162.1

1,163.87 

1,165.2 

1,166.3 

1,164.23 

1,167.7 

1,168.2

Stony Creek

Johnstown, 50 ft downstream from Washington St. bridge (R)

Bridge to incline plane (R)

State Highway 56 bridge

Central High School (L)

City Hall (R)

#86 Haynes St. (L)

Corner of Horner St. and Poplar St. 

(R)

Central Ave. bridge

Johnstown (R)

Ferndale, downstream side of State 

Highway 403 bridge (L)

50 feet upstream from State Highway 

403 bridge

Railroad bridge

#373 Michigan Ave. (R)

Fire Co. Building on Liberty Ave. 

(R)

0.03 

.38

.57 

.74 

.86 

1.03

1.51 

2.98 

3.42

3.81

3.83

4.19 

5.13

5.15

5.40

1,170.5 

1,171.4 

1,172.1 

1,173.2 

1,172.3 

1,173.9

1,175.4 

1,181.0 

1,183.0

1,188.0

1,191.0 

1,192.8 

1,203.5 

1,204.8

1.206.3

At State Highway 403 bridge ____. 

Riverside RD #3 (R) __________. 

Krings (L) _______________. 

Krings Road bridge _________. 

Ingleside, at sewage disposal plant (R). 

At road bridge _____________.

5.91

6.45

7.44

7.49

8.97

10.70

Shade Creek

1,212.8

1,216.6

1,238.6

1,242.3

1,288.4

1,329.82

Seanor, at highway bridge (L)

Camp Hamilton, at Windber Area 

School District Building

Old mill building

At road bridge

Paint Creek

At railroad bridge

Scalp Level, at confluence with Little 

Paint Creek (R)

Paint, at Main St. bridge over State 

Highway 56 (L)

Fire Dept building at #807 Main St. 

(R)

0.27

.86

3.02

3.16

5.20

0.06

2.52

2.63

2.64

1,503.8

1,528.2

1,646.8

1,653.8

1,777.0

1,325.3

1,660.4

1,665.3

1.670.7

TABLE 5. -Floodmark data - Continued

Stream and location

Stream 

mile

Elevation in 

feet above 

NGVD

Paint Creek Continued

Paint - Continued

Windber, at #702 Lincoln St. (R)

#100 Tenth St. (R)

#301 12th St. (R)

12th St. bridge

Corner of 17th St. and Graham Ave. 

(L)

#705 Graham Ave. (L)

#1010 17th St. (R)

2.87

3.14 

3.35 

3.50 

3.51

3.87 

3.92 

3.97 

4.23

1,672.0

1,676.0 

1,679.6 

1,684.1 

1,686.3

1,689.0 

1,692.0 

1,695.0 

1,702.3

Seese Run

Windber, at corner of 17th St. and 

Jefferson Ave. (R)

Windber (R)

Downstream side of 22nd St. bridge 

(R)

24th St. bridge

#2604 Jackson Ave. (R)

Corner of 28th St. and Jackson Ave. 

(R)

Corner of Village St. and Jackson 

Ave. (R)

#3104 Graham Ave

Main St. bridge

State Highway 56 bridge

At Spruce St. bridge

At downstream side of Graham Ave. 

bridge

At upstream side of Graham Ave. 

bridge

0.13 

.33

.50 

.67 

.79

.97

1.16 

1.26 

1.66 

2.12

2.24 

2.41 

2.42

1,688.2 

1,693.4

1,699.4 

1,707.8 

1,717.1

1,725.7

1,741.2 

1,746.1 

1,780.3 

1,821.6

1,833.0 

1,851.0 

1,852.3

Weaver Run

Windber (R)

At State Highway 56 bridge

Windber (R)

Windber (L)

At road bridge

At wooden, road bridge

0.05 

.06 

.10 

.43 

.68 

.88

1,698.5 

1,700.9 

1,701.2 

1,713.4 

1,728.4 

1,743.3

Little Paint Creek

Scalp Level (R)

At Methodist Church school building 

on Main St. (R)

Railroad bridge

Scalp Level (L)

At coal company boiler house (R)

Mine #40, at #1204 3rd St. (R)

At road bridge

At transformer station (L)

At downstream side of State Highway 

160 bridge

At upstream side of State Highway 160 

bridge

Elton (R)

Elton (R)

Elton, at Villard St. bridge

0.03

.18 

.27 

.35 

.67

.87

1.87 

2.51

2.88

2.88 

3.88 

4.01 

4.33

1,660.4

1,667.2 

1,674.1 

1,677.7 

1,704.5 

1,723.6

1,813.7 

1,885.2

1,930.6

1,933.0 

2,050.0 

2,061.3 

2,062.5

Sams Run

Johnstown, at railroad bridge

#77 Dupont St. (R)

Corner of Ohio St. and Central Ave. 

(R)

#534 Coleman Ave. (R)

Corner of Ohio St. and Grove Ave. (R)

#544 Grove Ave.

0.03 

.10

.16 

.31 

.33 

.36

1,184.1 

1,185.4

1,185.7 

1,193.6 

1,206.2 

1,209.2
66 JOHNSTOWN-WE STERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

TABLE 5.-Floodmark data- Continued

Stream and location

Sams Run Continued

Johnstown - Continued 

Corner of Ohio St. and Grove Ave. (R)

#544 Grove Ave.

Corner of Ohio St. and Highland Ave.

(R) -

Corner of Ohio St. and Forest Ave. 

(R) ___________________ _ 

Forest Ave. bridge

#239 Ohio St. (R)

Woodland Ave. bridge

Lorain, at #409 Valley St

#437 Valley St.

Solomon Run

Johnstown, at #837 Horner St. (R)

#821 Oak St. (R)

#722 Ash St. (R)

#714 Von Lunen St. (R)

#255 David St.

Corner of Bedford St. and Cummins 

St.

Walnut Grove, at #366 Arthur St. (R)

#1005 Jacoby St. (R)

Maple Park school building (R)

Bridge between State Highway 56 

and Bedford St.

#141 Purse St

#1088 Solomon St. (L)

#1139 Solomon St. (L)

Apartment building #6 (L)

Apartment building #9L (L)

#350 Solomon St. (L)

#1418 Solomon St. (L)

#1446 Solomon St. (L)

Stream 

mile

.33

.36

.49

.70

.73

.78

.78

1.00

1.10

0.03

.18

.27

.37

.52

.55

.76

.91

.97

1.01

1.05

1.08

1.19

1.39

1.53

1.72

1.85

1.91

Elevation in 

feet above 

NGVD

1,206.2

1,209.2

1,223.3

1,255.0

1,260.1

1,271.4

1,274.3

1,308.9

1 Q9fl fi

1,192.7

1,191.2

1,204.6

1,217.0

1,230.6

1,238.6

1,248.9

1,264.8

1,277.9

1,289.0

1,292.0

1,300.7

1,316.2

1,342.2

1,360.4

1,386.9

1,415.8

1,430.1

Little Conemaugh River

Johnstown (R) __________________________

Johnstown, at Johns St. bridge _____________

Corner of Locust St. and Walnut St. 

(L) _____________ _____________

Walnut St. bridge _____________________

Downstream side of railroad bridge _______

Upstream side of railroad bridge __________

Corner of Locust St. and Franklin St. 

(L) _____________________________

Johnstown (R) __________________________

Johnstown (L) __________________________

Downstream side of State Highway 

271 bridge _____ _______________ 

Upstream side of State Highway 271 

bridge _____________________________

School, 300 ft downstream from railroad bridge _________________________

Downstream side of railroad bridge _______

50 ft upstream from State Highway 

271 bridge __________________________

East Conemaugh, at #500 Railroad St.

(R) ______________ ___________

U.S. Geological Survey gaging station, 

100 ft downstream from State 

Highway 271 bridge (R) _..___________

Along Railroad St. (R) _________________

Along railroad tracks (R) _________________

At downstream side of railroad bridge _______

At upstream side of railroad bridge _________

Along railroad tracks, 470 ft upstream from 

railroad bridge to slag dump (L) _________

0.08 

.14

.30 

.31 

.38 

.38

.66 

.66

1.09

1.09

1.40

1.44

2.56

2.71

4.03

4.87

4.87

1,171.4

1,172.1

1,172.5

1,173.9

1,173.6

1,178.9

.51 1,173.4

1,179.3

1,180.9

1,187.8

1,191.0

1,196.8

1,199.9

2.01 1,214.0

2.40 1,220.2

1,226.8

1,228.9

1,266.9

1,289.4

1,293.2

5.13 1,316.8

TABLE 5,-Floodmark data- Continued

Stream 

Stream and location mile

Little Conemaugh River Continued

At Brookdale Mine #77 (R) _ 6.71

Mineral Point, downstream from highway 

bridge (R) 7.52

First house upstream from highway bridge 

(L) 7.57

Mineral Point (R) ___ ___ __ 7.90

At water supply dam _ _____ 11.22

South Fork, at downstream side of railroad 

bridge _ _ _ 11.91

Upstream side of railroad bridge ___ _ 11.91

Grant St. bridge _ _ _ 12.14

Ehrenfeld, at end of "A" St. (R) _______ 12.84

Summerhill (R) _ 13.88

Summerhill (R) _ __ __ __ _ 14.28

Summerhill, at service station upstream from 

State Highway 53 bridge (R) _ _ 14.40

At railroad bridge _ ____ _ 14.48

At downstream side of railroad bridge ____ 14.85 

At upstream side of railroad bridge 14.85

At downstream side of State Highway 53 

bridge __ _ 14.96

At upstream side of State Highway 53 

bridge _____ 14.96

At State Highway 53 bridge ___ 15.81

At downstream side of State Highway bridge _ 16.47 

At upstream side of State Highway 160 

bridge 16.47

Wilmore, at State Highway 160 bridge ___ 17.47 

Downstream side of railroad bridge _ _ 17.65

Upstream side of railroad bridge __ _ _ 17.65

Along Crooked St. (R) _ ~ 18.09

Along State Highway 53 (R) _ _ _ 18.63

Along State Highway 53, upstream from Trout 

Run (R) _ __ _ - 19.40

Portage, at State Highway 53 bridge __ _ 20.34

At downstream side of State Highway 160 

bridge _ - - 20.81

At upstream side of State Highway 160 bridge 20.81 

At road bridge upstream from Noels Creek 22.28

Oil City, at Bens Creek confluence (L) 23.53

At downstream side of railroad bridge 23 . 72

At upstream side of railroad bridge 23.72

Cassandra, at downstream side of highway 

bridge - 24.10

Upstream side of highway bridge _ 24.10

At downstream side of railroad bridge _ 24.36

At upstream side of railroad bridge 24.36

Spring Run

Portage, at road bridge, 950 ft upstream from 

mouth 0.19

State Highway 164 bridge .31

Road bridge .50

Trout Run

Portage, at athletic field (L) 0.25

500 ft downstream from Caldwell Ave bridge 

(L) _ ___ .49

Downstream side of Caldwell Ave. bridge _ .58 

Upstream side of Caldwell Ave bridge .58

Gillespie Ave. bridge .67

Conemaugh Ave. bridge .83

Sonman Ave. bridge .91

State Hforhwav 164 bridere .97

Elevation in 

feet above 

NGVD

1,361.4

1,380.4

1,379.3

1,385.2

1,470.1

1,478.6

1,479.2

1,480.2

1,497.6

1,526.4

1,531.6

1,536.8

1,538.7

1,540.2 

1,541.6

1,541.7

1,542.7

1,546.9

1,553.1 

1,554.7

1,556.7 

1,556.2

1,560.2

1,564.2

1,570.7

1,596.0

1,602.1

1,610.8

1,612.5 

1,647.3

1,734.1

1,744.5

1,747.1

1,774.4

1,778.6

1,801.4

1,803.6

1,607.8

1,616.7

1,638.9

1,620.9

1,643.4

1,655.2 

1,658.0

1,668.6

1,679.8

1,688.1

1,700.5

1,709.5
TABLES 67

TABLE 5.-Flood/mark data-Continued

Stream and location

Stream 

mile

Elevation in

feet above

NGVD

North Branch Little Conemaugh River

Wilmore, 50 ft downstream from railroad 

bridge

50 ft upstream from railroad bridge

State Highway 53 bridge

50 ft downstream from State Highway 160 

bridge

100 ft upstream from State Highway 160 

bridge

South Fork Little Conemaugh

South Fork, at Post Office (R)

Maple St. bridge

South Fork (R)

Soukesburg, at downstream side of State 

Highway 53 bridge

Upstream side of State Highway 53 bridge _

St. Michael, 80 ft downstream from railroad 

bridge

80 ft upstream from railroad bridge

Fire Dept. building (L)

Creslo, 80 ft upstream from road bridge (L) _

Sidman, at Adams-Summerhill High School 

(L) __ _

100 ft upstream from railroad bridge

40 ft downstream from State Highway 869 

bridge

30 ft upstream from State Highway 869 

bridge

Along road parallel to railroad tracks (R)

Allendale, 150 ft downstream from railroad 

bridge

50 ft upstream from railroad bridge

Along State Highway 869 (L)

Beaverdale, 50 ft downstream from State 

Highway 160 bridge

50 ft upstream from State Highway 160 

bridge

Lloydell, 50 ft downstream from State Highway 869 bridge

50 ft upstream from State Highway 869 

bridge

0.11

.13

.30

.62

.65

River

.08

.09

.40

1.68

1.68 

3.20

3.23

3.39

3.80

4.20

4.57

4.61

4.62

4.73

5.99

6.03

6.60

7.74

7.74

8.53

8.55

1,555.8

1,556.7

1,556.8

1,558.6

1,559.6

1,486.9

1,487.2

1,495.7

1,547.5

1,548.8 

1,580.4

1,582.3

1,584.3

1,598.6 

1,618.9

1,642.3

1,643.8

1,647.3

1,651.9

1,760.1

1,763.6

1,814.5

1,922.2

1,922.2

2,029.3

2,033.7

Sandy Run

[Data collected and compiled by the U.S. Geological Survey]

300 ft upstream from confluence with South

Fork Little Conemaugh River near

Soukesburg (R) ______________ .06 1,551.7 

150 ft upstream from road bridge (L) _____ .12 1,555.3 

At downstream side of bridge on entrance

road to U.S. Highway 219 South (L) ___ .20 1,570.5 

800 ft upstream from Liberty Park pool (L) _ .52 1,594.7

260 ft downstream from U.S. Highway 219

roadway culvert (L) ___________ .77 1,623.6 

760 ft downstream from U.S. Highway 219

bridge (R) _________________ .90 1,630.0 

230 ft downstream from U.S. Highway 219

bridge (R) _________________ 1.00 1,643.1 

70 ft upstream from U.S. Highway 219 bridge

(L) ______________________ 1.10 1,662.2 

600 ft upstream from U.S. Highway 219

bridge ___________________ 1.20 1,668.5

At embankment of old dam (L) ________ 1.40 1,689.0 

400 ft downstream from 18" culvert drain (R) _ 1.76 1,726.8

TABLE 5.-Floodmark data -Continued

Stream and location

Stream 

mile

Elevation in 

feet above 

NGVD

Sandy Run Continued

20 ft downstream from unnamed left bank tributary (L)

600 ft downstream from Sandy Run Dam (R) _ 

350 ft downstream from Sandy Run Dam 

(R, L)

50 ft upstream from centerline of dam (L) ____ 

140 ft upstream from centerline of dam (L) __

1.92 

2.11

2.16 

2.23

2.24 

2.25

1,741.8 

1,766.0

1,776.8

1,810.4 

1,810.5

St. Glair Run

Johnstown, at confluence with Conemaugh 

River

Intersection of Beatty Ave. and Enterprise 

St. (L)

Upstream side of Chandler St. bridge (R) __ 

Bachus St. bridge

Corner of "I" St. and Bheam Ave. (R)

Downstream side of Fairfield Ave. bridge _ 

Upstream side of Fairfield Ave. bridge _____ 

Road bridge at corporate boundary

At unnamed left bank tributary ____________ 

At road bridge _

At downstream side of road bridge

At upstream side of road bridge

0.00

.22 

.30 

.34 

.45 

.60 

.61 

1.07

1.38 

2.04 

2.58 

2.59

1,162.1

1,164.8 

1,175.7 

1,178.8 

1,188.9 

1,207.4 

1,211.5 

1,261.5

1,302.9 

1,382.1 

1,486.1 

1,489.8

Laurel Run

[Data collected and compiled by the U.S. Geological Survey]

At confluence with Conemaugh River at Johnstown's north corporate boundary (L) ____ 

90 ft upstream from State Highway 403 bridge 

(R)

90 ft upstream from State Highway 403 bridge 

(L) ___ _ ________

60 ft downstream from downstream side of 

Cooper Ave. bridge (R) _

60 ft upstream from upstream side of 

Cooper Ave. bridge (L) _

290 ft downstream from Wildcat Run (R) ____ 

140 ft upstream from Wildcat Run (L) _ _

Along left bank _

130 ft downstream from centerline of Cooper 

Ave. bridge (R) _

At upstream side of Cooper Ave. bridge (R) _ 

Along left bank

Along right bank

Along left bank _

At upstream side of Cooper Ave. bridge (L) _ 

At Methodist Church (R) _

220 ft upstream from Red Run (L) _

30 ft downstream from centerline of Laurel 

Run Dam (R) _

Centerline of Laurel Run Dam _____________ 

80 ft upstream from centerline of dam (R) ____ 

120 ft upstream from centerline of dam (R) _

0.00 

.08 

.32

.47

.49 

.68 

.76 

1.01

1.28 

1.31 

1.49 

1.57 

1.63 

1.73 

2.02 

2.33

2.51 

2.52 

2.53 

2.54

1,166.6 

1,164.1 

1,181.6 

1,199.0

1,200.9 

1,221.5 

1,229.4 

1,252.5

1,278.6 

1,280.8 

1,315.7 

1.332.2 

1,334.4 

1,349.3 

1,364.8 

1,392.8

1,400.8

1,437.5 

1,437.8

Blacklick Creek

At road bridge to Blairsville _ _ _ _ _

At Township Line bridge near Campbells Mills 

At road bridge near Grafton _ _ _

At U.S. Highway 119 bridge __ _ _ __

Josephine (R) _ _ _ _ _ _

Heshbon, at State Highway 259 bridge _ _

Dias, at State Highway 56 bridge _ _ _ _

Dilltown, at State Highway 403 bridge (L) _ 

Along Dilltown- Vintondale Road (R) _ __

Along Dilltown- Vintondale Road (L) ___ _

At new highway bridge near Wehrum

0.72 

6.37 

9.85 

10.78 

11.29

17.93 

21.33 

25.55 

27.97 

29.56 

30.50

958.8 

958.9 

969.8 

976.0 

994.8

1,254.3 

1,309.2 

1,350.7 

1,357.5 

1,364.9 

1,369.5
68 JOHNSTOWN-WESTERN PENNSYLVANIA STORM AND FLOODS OF JULY 19-20, 1977

TABLE 5.-Floodmark data-Continued

Stream and location

Stream 

mile

Elevation in 

feet above 

NGVD

North Branch Blacklick Creek

At highway bridge near Vintondale

Red Mill, at highway bridge

At U.S. Highway 422 bridge near mouth of Elk 

Creek

Adams Crossing bridge

0.05 

2.92

4.34 

5.61

1,392.5 

1,498.9

1,568.1 

1,613.2

South Branch Blacklick Creek

Vintondale, at #1002 Main St. (R)

#119 Main St. (R)

Church upstream from Main St. bridge (L) _ 

#637 Main St

Twin Rocks, at road bridge

At highway bridge near Twin Rocks

Nanty Glo, at corner of Rodgers St. and Lloyd 

St

State Highway 271 bridge

#18 McCoy St. (R)

At road bridge near Beula

0.06 

.30

.47 

.58

4.67 

5.13

7.15 

7.27 

7.62 

12.33

1,395.8 

1,396.2 

1,403.1 

1,404.3

1,644.7 

1,659.4

1,709.0 

1,713.7 

1,714.5 

1,842.2

Two Lick Creek

Coral, at highway bridge

Graceton, at highway bridge

U.S. Geological Survey gaging station (R) _ 

Homer City

At FMC plant downstream from State Highway 56 bridge (L)

#50 Indiana St. (L)

Jacksonville St. bridge

Along old U.S. Highway 119 (L)

At old U.S. Highway 119 bridge

Along U.S. Highway 119 at bridge over Stoney 

Run (R)

Upper Two Lick, at first dwelling downstream 

from State Highway 954 bridge (L)

First dwelling upstream from State Highway 

954 bridge (L)

Two Lick Station, at pump building at dam (R)

White Pine Park, at old U.S. Highway 422 (R) 

At Alien Road bridge

At road bridge 0.5 miles upstream from Penn 

Run

Sample Run

At State Hierhwav 286 bridere

2.26 

4.00

4.79 

6.07

6.40 

6.85 

6.95

7.96 

8.47

9.51 

11.81

11.83 

13.19

15.90 

18.16

20.42 

21.69 

22.38

985.0 

994.3 

1,000.3 

1,008.3

1,012.1 

1,015.4 

1,017.9

1,028.7 

1,033.4

1,046.9 

1,080.2

1,084.0 

1,102.2

1,188.8 

1,189.4

1,195.1 

1,208.2 

1.215.8

Clymer, at first dwelling upstream from State

Highway 286 bridge (R) __________ 22.40 1,218.9 

State Highway 403 bridge __________ 22.69 1,219.4

TABLE 5.-Floodmark data-Continued

Stream and location

Stream 

mile

Elevation in 

feet above 

NGVD

Two Lick Creek Continued

Corner of 4th St. and Sherman St. (L)

State Highway 286 bridge

Diamondville, along Water St., at 2nd dwelling downstream from Diamondville bridge 

(R) 

22.86 

23.15

26.65

1,220.1 

1,225.8

1,282.0

North Branch Two Lick Creek

Wandin Junction (R)

Starford, at #408 City Ave

Lovejoy

Commodore, at #19 Smith St

Seamentown (R)

Seamentown, at road bridge

0.13 

2.00 

2.18 

2.54 

3.32 

4.05 

4.20 

4.22

1,303.5 

1,340.6 

1,347.5 

1,369.5 

1,399.2 

1,424.4 

1,425.6 

1,428.6

Buck Run

Buck Run, at double 5-ft diameter pipe culvert 

At bridge on private road

At State Highway 286 bridge

At downstream side of road culvert

1.26 

1.35 

1.89 

2.28 

2.28

1,324.5 

1,330.7 

1,373.9 

1,404.0 

1,407.1

Dixon Run

Clymer, at #13 Lee St(L)

Penelec substation (R)

Rembrant, at State Highway 403 bridge

Dixonville, at Dixonville Moose Lodge #833 _ 

Along State Highway 403 at bridge #6 (R) __

Idamar, at 5-ft diameter pipe culvert

0.27 

.38 

.41 

1.55 

2.10

2.87 

3.42 

3.82 

4.61 

5.01 

5.74

1,220.2 

1,220.6 

1,221.8 

1,244.7 

1,250.0

1,264.6 

1,273.4 

1,277.9 

1,308.1 

1,321.2 

1,370.4

Yellow Creek

Homer City, at railroad bridge

#216 N. Main St. (R)

#36 Maple Ave

Private dwelling just downstream from 

Mazza St. bridge (R)

22 N. Water St. (R)

U.S. Highway 119 bridge

At State Highway 954 bridge

Heilwood, at State Highway 403 bridge

0.30 

.39 

.43

.72 

.77 

.82 

.92 

.93

1.59 

3.44 

20.25

1,015.9 

1,020.7 

1,021.4

1,027.2 

1,028.3 

1,031.2 

1,033.6 

1,034.1

1,039.5 

1,090.1 

1,501.3