U.S. Department of the Interior

U.S. Geological Survey Printed on recycled paper

Fact Sheet 2007-3099

December 2007

Surface-Water Techniques: On Demand Training 

Opportunities

The U. S. Geological Survey (USGS) has 

been collecting streamflow information since 1889 using nationally consistent 

methods. The need for such information 

was envisioned by John Wesley Powell as 

a key component for settlement of the arid 

western United States. Because of Powell’s 

vision the nation now has a rich streamflow data base that can be analyzed with 

confidence in both space and time. This 

means that data collected at a stream 

gaging station in Maine in 1903 can be 

compared to data collected in 2007 at the 

same gage in Maine or at a different gage 

in California. Such comparisons are becoming increasingly important as we work 

to assess climate variability and anthropogenic effects on streamflow. Training 

employees in proper and consistent techniques to collect and analyze streamflow 

data forms a cornerstone for maintaining 

the integrity of this rich data base.

Data collection techniques used at the first 

USGS streamgaging stations were developed 

and taught at Embudo, New Mexico. The handful of student hydrographers who learned 

these techniques were distributed throughout the western United States where they 

set about establishing what is now the U.S. 

Geological Survey’s streamgaging network. 

The USGS now employs hundreds of hydrographers who measure streamflow at over 7000 

gaging stations in all 50 States, Puerto Rico, 

Guam, and the Virgin Islands. Those employees must continue to use standard practices to 

collect streamflow data if the integrity of the 

data base is to be maintained. To help USGS 

employees (and employees of other agencies 

who have a need to collect streamflow data) 

keep abreast of current USGS streamgaging 

techniques, a variety of training classes have 

been developed. Designed to augment traditional classroom-style training and published 

technique manuals, these classes are available 

either on CD-ROMs or over the Internet.

This Fact Sheet with live links to the on-line on demand training material described here 

and any updates to it are available online at: 

http://pubs.usgs.gov/fs/2007/3099/
Available Classes 

Web-Based Classes

Surface-Water Field Methods 

This class provides a basic understanding of 

techniques the U.S. Geological Survey uses to collect data at streamflow gaging stations. The class 

reviews:

•	 How gage sites are selected,

•	 What controls the relation between stream stage and 

discharge, 

•	 How stream stage is measured, 

•	 How stream discharge is measured.

You can also take virtual visits to two streamgages from this training class. This class is listed 

as Training Class SW4230 with the USGS National 

Training Center. 

Stage-Discharge Relations: Basic Concepts

At most streamgaging stations stream discharge is estimated by applying the relation 

between stream stage, which is measured continuously, and discharge. This class provides a basic 

understanding of techniques the U.S. Geological 

Survey uses to develop these important relations. 

The class reviews:

•	 What controls the relation between stage and dis- charge,

•	 How stage-discharge relations are plotted and why 

they are plotted this way, and 

•	 What to do when stage-discharge relations change.

A set of fourteen exercises accompany this 

class. USGS employees can take a modified version 

of this class that uses the graphical tool “GRSAT” 

to work class exercises. This class is listed as 

Training Class SW1409 with the USGS National 

Training Center.

Measurement of Stream Discharge by Wading

Most years the USGS makes over 50,000 

stream discharge measurements. Over 75 percent of those measurements are made by wading 

streams and using the velocity-area method. This 

class describes how stream discharge should be 

measured when wading and using the velocityarea method. It is intended as a learning and reference tool for anyone responsible for making wading discharge measurements. This class, which 

was originally published on CD-ROM, has recently 

(2007) been revised and is now web-based. The 

class is listed as Training Class SW1271 with the 

USGS National Training Center.

Photo of Robert Erickson reading the gage height at a streamgaging 

station using a wire-weight gage.

Photo of Ron Shields measuring the discharge of the Blackfoot River 

in Montana.

Photo of the artificial control that stabilizes the stage-discharge relation 

at a gaging station on San Francisquito Creek at Stanford, CA.
made regularly during the winter because the quality of long periods of winter streamflow data are 

often dependant on “ice measurements”. This class 

is listed as Training Class SW4288 with the USGS 

National Training Center.

Stream Discharge Measurements From Cableways

Cableways have been used for decades as a platform for making stream discharge measurements. 

Use of cableways eliminates the need to expose 

personnel to hazards associated with working from 

highway bridges. In addition, cableways allow sites 

to be selected that offer the best possible hydraulic 

characteristics for measuring stream discharge. This 

training presentation describes methods currently 

used by the U.S. Geological Survey to make stream 

discharge measurements from cableways. The class 

is listed as Training Class SW4292-TC with the USGS 

National Training Center.

Levels at Streamflow Gaging Stations

Streamgages record the elevation of the water 

surface above some reference surface, or datum. 

This datum is assumed to remain unchanged 

Cableway Safety Training Class: Pre-Use Inspection

Cableways, which are used regularly as platforms from which to make streamflow discharge 

measurements, impose unique risks to streamgagers. This class is designed for all cableway users and 

outlines how to inspect a cableway before it is used. 

The class describes: 

•	 Basic cableway nomenclature. 

•	 How cableways are used during a discharge measure- ment,

•	 A description of all major cableway components,

•	 Forces in action during cableway use, 

•	 Inspection procedures required before operating a 

cableway, and 

•	 Rules for safe cableway operation. 

CD-Based Classes:

Stream Discharge Measurements Under Ice Cover

This training presentation shows procedures 

used by the U. S. Geological Survey to measure 

streamflow when streams are covered by ice. 

Although “Ice Measurements” are generally more 

difficult to make than open-water measurements 

and are often made under uncomfortable conditions, it is very important that ice measurements be 

Photo of Lucky Sultz inspecting a streamgaging cableway prior to 

use.

Photo of Jake Jacobson and Stan Landon measuring the discharge of 

Pacific Creek at Moran, Wyoming under ice cover.

Photo of Lucky Sultz using the streamgaging cableway across the 

Middle Fork Flathead River in Montana.

Photo of Stan Landon and Jake Jacobson running gaging stations 

levels at a gage on the Henry’s Fork River in Idaho.
throughout the life of the gage. However, the elevation of gages and their supporting structures often 

change over time as a result of ground movement, 

floods, ice, and debris. The surveying practice of 

leveling is used to establish datum for new gage 

structures and to check for vertical movement of 

those structures over time. Vertical changes in 

gage structures can affect stage-discharge relations and, thus, could result in incorrect discharge 

determinations. Datum checks are used to correct stage-discharge relations and allow the USGS 

to document gage datum throughout the life of a 

gage. This training presentation describes methods currently used by the U.S. Geological Survey 

to run levels at gaging stations. The class is listed 

as Training Class SW1307 with the USGS National 

Training Center.

Introduction to Suspended-Sediment Sampling 

Knowledge of the amount and timing of sediment transport in streams is important to those 

directly or indirectly responsible for developing 

and managing water and land resources. Such data 

are often used to judge the health of watersheds 

and the success or failure of activities designed to 

mitigate adverse impacts of sediment on streams 

and stream habitats. This training class presents 

an introduction to methods currently used by the 

USGS to sample suspended-sediment concentrations and particle-size distribution in streams. The 

class is listed as Training Class SW4416 with the 

USGS National Training Center.

Taking the classes

Classes are linked to a summary web page at:

http://wwwrcamnl.wr.usgs.gov/sws/SWTraining/Index.htm

All classes are USGS publications and, as such, 

are available to USGS employees as well as to the 

general public. Most classes are narrated and 

many contain video clips that illustrate selected 

concepts. Videos associated with the web-based 

classes are best viewed using a relatively highspeed internet connection. 

Most classes contain tests that can be used by 

students and/or supervisors to assess how well 

students understand class materials. Certificates 

can be downloaded and filled out by students and 

supervisors to demonstrate successful completion 

of a class. 

We will continue to update existing training 

materials and hope to develop training opportunities on additional subjects. 

Contact Information: K. Michael Nolan

kmnolan@usgs.gov

References

Frey, C. and Nolan, K.M., 1999, Cableway Safety Training Class: 

Pre-use inspection, U. S. Geological Survey WRI 99-4038, at: 

http://wwwrcamnl.wr.usgs.gov/sws/cableways/

Nolan, K. M., Frey, C. and Jacobson, J., 1998, Surface-water 

field techniques training class, U. S. Geological Survey WRI 

98-4252, Version 2, at: http://wwwrcamnl.wr.usgs.gov/sws/

SWTraining/FlashFandR/Index.html

Nolan, K. M., Shields, R. R. and Rehmel, M., 2000, Measure- ment of stream discharge by wading, U. S. Geological Survey 

WRI 2003-4103, at: http://wwwrcamnl.wr.usgs.gov/sws/

SWTraining/WRIR004036/Index.html

Nolan, K. M. and Shields, R. R., 2000, Measurement of stream 

discharge by wading, U. S. Geological Survey WRI 2003-4103, 

CD-ROM, various pages

Nolan, K. M. and Jacobson, N. D., 2000, Stream discharge 

measurements under ice cover, U. S. Geological Survey WRI 

00-4257, CD-ROM, various pages

Nolan, K. M. and Sultz, L., 2000, Stream discharge mea- surements from cableways, U. S. Geological Survey WRI 

2001-4102, CD-ROM, various pages

Nolan, K. M., Jacobson, N., Erickson, R. and Landon, S., 2003, 

Levels at streamflow gaging stations—A CD-ROM based 

training class, U. S. Geological Survey WRI 2003-4002, CDROM, various pages

Nolan, K.M., Bohman, L., Stamey, T. and Firda, G., 2005, Stagedischarge relations—basic concepts, U. S. Geological Survey 

SIR 2005-5028, at: http://wwwrcamnl.wr.usgs.gov/sws/

SWTraining/RatingsWeb/Index.html

Nolan, K. M., Gray, J.R., and Glysson, G.D., 2005, Introduction to 

suspended-sediment sampling, U. S. Geological Survey SIR 

2005-5077, CD-ROM, various pages

Photo of John Gray sampling suspended-sediment concentration of 

the Little Colorado River at the mouth near Desert View, Arizona.