U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2009–3048

November 2009

Streamgaging in Pennsylvania: 1883–2009

Introduction

The Commonwealth of Pennsylvania contains 

83,602 miles of streams within its borders. These streams 

are natural resources that influence the lives and economy of 

Pennsylvania residents daily. The water resources are used on 

a daily basis for recreation, power generation, drinking water, 

agriculture, industry, and many other uses, emphasizing the 

importance of this valuable resource. The effects of too much 

or too little water can be devastating to communities throughout 

the Commonwealth. The amount of water (flow) in a stream has 

been a critical piece of information since before the founding 

of Pennsylvania. In 1612, John Smith navigated the “Sasquesahanough” River while exploring the newly discovered territory 

(Haile, 1998). In 1630, Dutch pioneers traveled up the Delaware 

River to settle in Bucks County.

Historical Streamgaging Activities

The first documented streamflow measurement (streamgaging) in Pennsylvania was in the Philadelphia area by the 

Department of Public Works. Measurements of flow from four 

locations in the Delaware River Basin were documented and 

published, beginning in 1883.

The first streamgaging station operated in the United States 

by the U.S. Geological Survey (USGS) was established in 1889 

on the Rio Grande near Embudo, N.M. Specific appropriation 

for streamgaging was made by the Act of August 18, 1894, 

which contained the budget line item of $12,500 “for gauging 

the streams and determining the water supply of the United 

States, including the investigation of underground currents and 

artesian wells in the arid and semiarid sections” (Grover and 

Hoyt, 1906).

As annual appropriations for hydrographic surveys 

increased, the work of the USGS was expanded and organized 

by the adoption of standard methods and by grouping states into 

Districts. In each District, a District Hydrographer and a corps 

of assistants collected data to study the hydrographic resources. 

As a result of the Act of August 18, 1894, the states of Pennsylvania, Maryland, Virginia, and West Virginia were combined to 

form the Middle Atlantic District.

Systematic streamgaging by the USGS in Pennsylvania 

began in the 1890s. E.G. Paul, the resident hydrographer of the 

Middle Atlantic District, made the first flow measurements by 

the USGS at several locations on main-stem streams throughout 

the Commonwealth in the late 19th century, including the earliest documented flow measurements completed in 1897 on the 

Susquehanna River at Harrisburg.

In 1904, streamgaging was extended into western Pennsylvania, where a group of streamgaging stations was established 

in the headwaters of the Ohio River.

In 1907, because of a reduction of Federal appropriations, 

the USGS streamgages in Pennsylvania were turned over to the 

Pennsylvania Water Supply Commission. By the end of 1909, 

only seven streamgages in Pennsylvania were maintained by the 

original USGS Middle Atlantic District.

By 1910, the staff of the Water Supply Commission in 

Pennsylvania were making flow (discharge) measurements at 72 

locations across the Commonwealth—20 in the Delaware River 

Basin, 23 in the Susquehanna River Basin, 2 in the Potomac 

River Basin, and 27 in the Ohio River Basin.

In 1923, during the first administration of Governor 

Gifford Pinchot, the Department of Forest and Waters and its 

administrative arm, the Water and Power Resources Board, 

were created. This change combined the Water Supply Commission with the Forest Service of the Department of Forestry.

In 1931, the Pennsylvania Department of Forest and 

Waters and the USGS entered into a cooperative agreement 

that provided for collecting and reporting streamflow data in 

Pennsylvania. A surface-water district office was established 

at Harrisburg on June 1, 1931. This was the start of the USGS 

Pennsylvania District (now located in New Cumberland, Pa.). 

The cooperative program was placed under a district engineer 

Hydrographer making a cable-car measurement

Printed on recycled paper
of the USGS, who would become Chief of the State WaterResources Service. Those Service personnel consisted of both 

Commonwealth and USGS employees. The program consisted 

of 97 streamgages and included the collection of other hydrologic data needed for the forecasting of floods.

Following the flood of March 1936, an increase in Commonwealth funding allowed for more streamgages and additional hydrologic investigations. As a direct result, a subdistrict 

office of the USGS Pennsylvania District was established in 

Pittsburgh in 1938.

Prior to 1936, the cooperative program was only with the 

Commonwealth of Pennsylvania. Between 1936 and 1940, two 

new cooperators, the cities of Harrisburg and Bethlehem, joined 

with the USGS Pennsylvania District to operate streamgages 

in connection with their water supply. The city of Bethlehem 

remains a cooperator today.

Over the next few decades, the Pennsylvania streamgaging 

network expanded steadily. As a result of a large increase in the 

number of streamgages in the Philadelphia area, a subdistrict 

office of the Pennsylvania District was established in Philadelphia in 1965 (now located in Exton, Pa.). Following the 1972 

flooding that resulted from Hurricane Agnes, a determination 

was made to establish a field office in central Pennsylvania. In 

1974, a field office began operating out of Williamsport. By 

1977, the number of streamgages had grown to about 260.

In 1986, the USGS, the National Weather Service (NWS), 

and the Susquehanna River Basin Commission (SRBC) partnered to develop a state-of-the-art Flood Forecast and Warning 

System in the Susquehanna River Basin. That same year, the 

Pennsylvania Department of Environmental Resources, Bureau 

of Water Resources Management, partnered with the USGS to 

upgrade many of the cooperative streamgaging sites to include 

satellite telemetry for transferring data to the USGS computer 

databases. These partnerships substantially increased the number of streamgages in Pennsylvania and allowed for an upgrade 

of the majority of the streamgaging network to include satellite 

telemetry.

Today the staff of the USGS Pennsylvania Water Science Center (PaWSC, formerly the Pennsylvania District) is 

operating a network of nearly 240 streamgages, in cooperation 

with about 53 Federal, State, and local partners. The gages in 

Pennsylvania are maintained from the four offices within the 

Commonwealth.

Advances in Streamgaging Technology

Many advances have been made in the collection and 

processing of stream-surface elevation (stage) and flow data. 

In early years, stage data were collected by observers reading 

manual gages (such as a 

staff gage). That process 

eventually evolved to 

an automated process 

of a float and tape 

stilling-well system that 

recorded stage on either 

an analog strip-chart 

recorder or a digital 

‘punch’ paper-tape 

recorder.

In Pennsylvania, 

the first documented 

automatic stage recorder 

was installed on Wallenpaupack Creek at 

Wilsonville in 1913. The 

first recorder installed 

by USGS hydrographers 

was on the Loyalsock 

Creek streamgage at 

Loyalsockville in 1925.

By 1928, 10 streamgages had been equipped with automatic recorders. At the time of the new cooperative program 

with the Commonwealth in 1931, 47 of the 97 streamgages 

were automated.

As technology improved, sites where data were collected 

with sufficient frequency to define a daily mean flow (discharge) 

along with stage variations within a day (continuous-record 

stream stage) became the model for streamgaging throughout 

the Commonwealth.

Today, stations used to compute discharge are 100-percent 

automated. The PaWSC maintains about 240 continuous-record 

streamgages within the Commonwealth. Stream-stage data are 

generally collected at 15-minute intervals.

The USGS in Pennsylvania has been a leader in the testing, 

development, and deployment of the satellite-telemetry method 

to transmit streamflow data. As part of the Water Resources 

Division (WRD) Satellite Data Relay Project beginning in 1974, 

Pennsylvania participated in the testing of the Earth Resources 

Technology Satellite (ERTS) and the Geostationary Operational 

Environmental Satellite (GOES) data-collection systems.

By 1977, the Pennsylvania USGS offices had become 

leaders in data collection and transmissions using the GOES 

data-collection system. Of the nearly 260 continuous-record 

streamgages in operation at that time, about 10 percent were 

collecting and transmitting data at 2- to 4-hour intervals through 

the GOES data-collection and transmission system.

In the early 1980s, with cooperation from one of our Federal partners, the U.S. Army Corps of Engineers (USACE), the 

streamgages providing data to support the USACE flood-control 

projects were upgraded to a state-of-the-art satellite-telemetry 

system.

Today, water-resources data are transmitted from nearly 

430 data-collection platforms at streamflow, precipitation, USGS offices in Pennsylvania

EXTON

OFFICE

PITTSBURGH

OFFICE NEW

CUMBERLAND

OFFICE

WILLIAMSPORT

OFFICE

Outside vertical staff gage used to 

measure the depth of the water
groundwater, and water-quality data-collection sites throughout 

the Commonwealth. These data are processed and delivered 

real time through the internet to the public and our cooperators. 

Recent technology allows many of those locations to transmit 

data on an hourly basis. This feature has greatly enhanced the 

ability of our partners to manage the water resources within the 

Commonwealth.

Historically, Pennsylvania collected streamflow data using 

mechanical current meters to physically measure the water 

velocity along with other physical methods to measure stream 

width and depth. Although these methods and instruments have 

proven to work well, new technological advancements have 

improved the way those data are collected.

The PaWSC has made a commitment to upgrade its capabilities to collect flow data using the newest acoustic technology 

available. Each hydrographer in the PaWSC has been supplied with an acoustic doppler current meter. The PaWSC also 

has purchased a number of acoustic doppler current profiler 

(ADCP) systems. The ADCP is an acoustic instrument used 

to measure water velocities. Water-velocity measurements are 

made by transmitting sound at a known frequency into the water 

and measuring the Doppler shift, or change in sound frequency, 

from signals reflected off particles in the water. ADCPs also 

can measure water depths and, when deployed from a moving boat, can measure the velocity of the boat. The capability 

of ADCPs to measure water velocity, depth, and boat velocity 

allows them to be used to measure discharge in rivers and estuaries, especially during extreme and unsteady conditions. The 

primary advantages of making discharge measurements using 

the ADCP as compared with point-velocity meters, such as the 

Price AA current meter, are that in most situations 

(1) the time required to complete a measurement 

is reduced, an advantage for personnel safety 

and for making measurements in unsteady-flow 

GOES DOMSAT

Wallops, Virginia,

Command and

Data Acquistion Center

NWISWeb and

Data Users

USGS

Database

Path of data flow from field to user

ADCP mounted on a tether boat

Stream gager making a streamflow measurement using a bridge 

crane and a current meter

Number of streamgages in operation in Pennsylvania since 1900

19001905191019151920

19251930193519401945195019551960

196519701975198019851990199520002005

Year

Number of Gages

Drought 1930-34

Flood 1936

Drought 1961-67

Agnes Flood 1972

300

250

200

150

100

50

0
conditions; (2) the ADCP allows data to be collected throughout most of the water column and cross section rather than at 

discrete points; (3) the ADCP is deployed at the water surface, 

appreciably reducing the chance of snagging by debris, another 

safety advantage; (4) the instrument can be boat-mounted, thus 

eliminating the installation, maintenance, and liability of costly 

manned cableways; (5) complex flow regimes, such as vertical 

bi-directional flow, can be accurately identified and measured; 

and (6) many parameters are available for analyzing the quality 

of the streamflow measurement.

Pittsburgh

Johnstown

Altoona

State College

Harrisburg

York

Lancaster

Philadelphia

Allentown Bethlehem

Reading Reading

Erie

Scranton

Wilkes-Barre

STREAMGAGE 

PERIOD OF RECORD 

1–24 YEARS

25–49 YEARS

50–74 YEARS

MORE THAN 74 YEARS

Williamsport

Location and period of record for Pennsylvania streamgages

In addition, the PaWSC is continually striving to develop 

and test new methods for non-contact stage and velocity measurement of streams. An ongoing project to develop and test 

instrumentation will accurately read surface velocities within a 

river system, use those velocities to compute a discharge, and 

transmit those discharge values in real time to our partners. 

These data will be most valuable to our partners during times of 

unsteady flow when, for example, ice or debris jams are causing 

pooling and backwater conditions.

The PaWSC continues to build on their core capabilities 

to collect, analyze, and disseminate hydrologic data. The 21st 

century brings unprecedented opportunities in streamgaging and 

hydrologic investigations.

Continuing stresses on water resources within the Commonwealth will require the PaWSC to maintain a stable 

long-term network of data-collection sites and the most technologically advanced data-collection systems available. An understanding and characterization of the natural hazards and water 

availability within Pennsylvania are critical to the economy, 

water resources, and quality of life of our citizens. The USGS 

PaWSC will strive to continue to have a major role through its 

streamgaging network to provide for the growing needs of the 

Commonwealth for surface-water information.

By Randall R. Durlin

References Cited

Grover, N.C., and Hoyt, J.C., 1906, Report of progress of 

stream measurements for the calendar year 1905, Part III, 

Susquehanna, Gunpowder, Patapsco, Potomac, James, Roanoke, and Yadkin River drainages: U.S. Geological Survey 

Water Supply Paper 167, 128 p.

Haile, E.W., 1998, Jamestown narratives—Eyewitness account 

of the Virginia colony, the first decade, 1607–1617: RoundHouse, 946 p.

Bridge-mounted radar water-level sensor