U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2014–3034

April 2014 Printed on recycled paper

John Wesley Powell, second Director of the U.S. Geological Survey (USGS), had a vision for the Western United States. In the 

late 1800s, Powell explored the West as head of the Geographical and Geological Survey of the Rocky Mountain Region. He devoted a 

large part of “Report on the Lands of the Arid Region of the United States with a more detailed account of the land of Utah with maps,” 

his 1878 report to the General Land Office on the lands west of the 100th meridian, to the feasibility of “reclaiming” large portions of 

this arid land (Powell, 1879).

Powell recognized that the availability of water was key to the wise settlement of the region. He proposed to inventory all streams 

in the West to evaluate the potential for irrigation. The essential first step was to gage the flows of the rivers and streams.

A few cities in the Eastern United States had established primitive streamgages as early as the 1870s to acquire data needed for the 

design of their water supply systems. Their methods generally used constructed channels and dams to enable accurate gaging. These 

methods were not feasible in the West, and certainly not on the vast scale and extreme range of flows common to western streams. New, 

more flexible techniques were needed. A site was chosen where these methods could be worked out and developed in a practical setting.

 amp Embudo and the First

USGS Streamgage

A site on the Rio Grande near the town of 

Embudo, New Mexico, was established as the 

first USGS training camp for hydrographers. 

Frederick H. Newell, first appointed by Powell 

as assistant hydraulic engineer and later serving 

as first director of the Bureau of Reclamation, 

was in charge of the camp. The camp was 

established in December of 1888 with a class

of 14 student hydrographers. Staff included

3 instructors, 2 laborers, a packer, and a cook. 

Because equipment was initially lacking, 

the students used float measurements and crosssectional surveys to compute discharge. Later, 

an oceanographic current meter borrowed from 

the U.S. Coast and Geodetic Survey and the 

Navy Department was modified to fit the unique 

challenges of the Rio Grande: shallow, fastmoving water and soft, mobile channel beds. 

Ultimately, the students fabricated improved 

velocity meters and suspension systems to 

measure the essential elements of streamflow: 

cross-sectional area and velocity.

The Rio Grande at Embudo streamgage 

was established adjacent to the railroad 

station in January 1889, becoming the first 

USGS streamgage. Official training at Camp 

Embudo ended in April 1889, with 10 students 

completing the training to be classified as 

“hydrographers” or “assistant hydrographers.” 

The newly trained hydrographers dispersed to 

locations throughout the West.

Rio Grande

Embudo
hy a Remote Outpost Like Embudo?

Congressional funding for the Irrigation Survey (an early 

branch of the USGS) was intended for the arid West, meaning 

all land west of the 100th meridian. A component of the planned 

irrigation survey was an inventory of all streamflow in order to 

evaluate the irrigation potential to nearby land areas. The first 

step in this inventory was to train hydrographers and develop 

equipment and techniques for measuring streamflow in an arid 

environment. Getting the program underway as soon as possible 

after Congressional funding in October 1888 meant that weather 

was a consideration. Most northern streams would soon be 

frozen, leaving the southwest as the only practical alternative. 

Embudo was located far enough south for the Rio Grande to 

have flowing water throughout the winter. In addition, railroad 

transportation connected directly with the Embudo site, 

expediting transport of personnel and equipment and providing 

access to outside resources. This access would become 

important in the development and adaptation of equipment 

and techniques that would become the foundation of USGS 

streamgaging methods.

These are the words C.E. Dutton, head of the 

Hydrographic Branch of the Hydraulic Survey, a division 

of what was then the Irrigation Survey, used to describe the 

trainees who became the first group of USGS hydrographers. 

Many of them were newly graduated engineers from colleges 

in the East, and only one had prior experience in the West. 

Winter at Camp Embudo, at an elevation of over 5,800 feet, 

was cold. Most of the men abandoned their cots to sleep in 

shallow trenches dug in the dirt floors of their Army tents, and 

a few excavated a cave into a nearby hill. Training continued 

through April, after which the men dispersed throughout the 

West. Techniques and equipment developed at Camp Embudo 

became the foundation of the Irrigation Survey program and, 

later, of the USGS systematic streamgaging program. This 

photograph shows only part of the group. 

“

en of Good Education and High General Intelligence
ioneers of the Craft

Embudo, the Spanish word for “funnel,” describes the 

convergence of the San Juan Mountains and Culebra Range 

foothills that created a defined channel cross section for 

experimentation and refining of streamgaging equipment 

and techniques. After acquiring some experience, students 

were sent off to nearby streams to test their abilities to select 

suitable gaging sites, install streamgages, and make streamflow 

measurements. The hand-drawn cross sections below were 

constructed in making discharge measurements on the Rio 

Grande and Embudo Creek.

efining the Tools

Adapting and improving equipment and techniques for 

use in the West were important activities at Camp Embudo. 

Improved methodologies were developed for the measurement 

of stream velocity, suspended sediment, and bedload, and for 

making weather observations. A device for measuring the 

velocity of flowing water, called a velocity or current meter, 

was furnished by the U.S. Navy. This meter was modified over 

successive trips to an instrument shop in Denver, Colorado, 

to better accommodate the shallow water and streamflow 

conditions of the Rio Grande at Embudo. Other types of rodsuspended meters were improved upon as well, and experiments 

with these meters refined techniques for measuring stream 

velocity, some of which are still in use today.
he Evolution of Streamflow Measurement Techniques he USGS Streamgage Network

Equipment was refined over the years, but the basic design 

of mechanical velocity meters and streamflow measurement 

techniques remained essentially the same throughout the 

1900s. Mechanical velocity meters in the form of rod- or 

cable-suspended meters with rotating cups were the norm and 

continue in use today. In recent years, velocity meters have 

been largely replaced by hydroacoustic equipment such as 

the acoustic Doppler current profilers (ADCPs). An ADCP 

measures the Doppler shift in the frequency of acoustic signals 

that are reflected from materials suspended in and moving with 

the water to estimate flow velocity and that are reflected from 

the river bed to compute boat location and channel width. It 

uses the time of travel of signals reflected from the riverbed to 

estimate channel depth.

Use of hydroacoustic technology has improved efficiency 

and increased the quality of discharge measurements, and 

has made it possible to determine discharge in some flood or 

low-flow conditions where measurement was not previously 

possible. The use of hydroacoustic instruments has developed 

rapidly since 2000, and at present (2014), 80 percent of USGS 

discharge measurements use hydroacoustic instruments. For 

more information, visit http://hydroacoustics.usgs.gov/.

Interest in USGS methods of streamgaging quickly spread 

east. Streamflow information was needed there to manage water 

supplies and to design hydroelectric powerplants. For 125 years, 

USGS streamflow information has provided the scientific basis 

for protecting, managing, and sustaining freshwater that is safe 

and available for drinking and other competing water demands, 

including irrigation, energy, industry, recreation, and ecosystem 

health. With the ability to transmit collected data from field 

sites to USGS offices by satellite, phone, or radio, much of the 

information is available in near-real time (http://waterdata.usgs.

gov/nwis), which is critical to protect and minimize loss of life 

and property from water hazards, including floods, droughts, 

and debris flows.

The USGS streamgage network, like many USGS Water 

Resources programs, depends on partner funding. More than 

70 percent of about 8,000 streamgages across the Nation are 

supported through joint contributions by more than 850 local, 

State, and tribal partners and the USGS to address specific 

partner priorities through the Cooperative Water Program 

(https://water.usgs.gov/coop/). Federal partners support 

streamgages providing data critical to the operation of other 

Federal programs. In addition, about 3,100 streamgages meet 

the targeted, long-term priorities established by the National 

Streamflow Information Program (http://water.usgs.gov/nsip/). 

This program is designed to meet Federal responsibilities 

associated with flood forecasting; monitoring flows across 

international, interstate, and tribal borders; tracking flow in 

major river basins; and assessing long-term climatic, land-use, 

and human impacts on streamflow and water quality in different 

environmental settings across the Nation.

Most USGS streamgages provide information for more 

than one use. Uses of the streamflow information collected at 

Embudo are a case in point: The National Weather Service uses 

the information for river forecasts, but local, State, and Federal 

agencies also use the data (1) to account for inflow from the 

Rio Grande above the Rio Chama as part of the Rio Grande 

Compact, (2) to help time releases and account for waters 

from the San Juan-Chama transbasin diversion, and (3) to help 

establish and protect water rights.

Frazier, A.H., and Heckler, Wilbur, 1972, Embudo, New Mexico, 

birthplace of systematic stream gaging: U.S. Geological 

Survey Professional Paper 778, 23 p., http://pubs.usgs.gov/

pp/0778/report.pdf. 

Powell, J.W., 1879, Report on the lands of the arid region of 

the United States with a more detailed account of the land 

of Utah with maps: U.S. Geological Survey Unnumbered 

Series Monograph, 193 p., 3 pls., http://pubs.usgs.gov/

unnumbered/70039240/report.pdf.

Stegner, W.E., 1954, Beyond the hundredth meridian—John 

Wesley Powell and the second opening of the West: Lincoln, 

Nebr., University of Nebraska Press, 438 p.

—By Mark A. Gunn, Anne Marie Matherne, and

Robert R. Mason, Jr.

Publishing support provided by

Lafayette Publishing Service Center

ISSN 2327-6916 (print)

ISSN 2327-6932 (online)

http://dx.doi.org/10.3133/fs20143034

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