U.S. Geological Survey (USGS) Streamgaging Network: Overview and Issues for Congress

U.S. Geological Survey (USGS) Streamgaging
March 2, 2021
Network: Overview and Issues for Congress
Anna E. Normand
Streamgages are fixed structures at streams, rivers, lakes, and reservoirs that measure water level
Analyst in Natural
and related streamflow—the amount of water flowing through a water body over time. The U.S.
Resources Policy
Geological Survey (USGS) in the Department of the Interior operates streamgages in every state,

the District of Columbia, and the territories of Puerto Rico and Guam. The USGS Streamgaging
Network encompasses 11,340 streamgages, which record water levels or streamflow for at least a

portion of the year. Approximately 8,460 of these streamgages measure streamflow year round as
part of the National Streamflow Network. The USGS also deploys temporary rapid deployment gages to measure water le vels
during storm events, and select streamgages measure water quality.
Streamgages provide foundational information for diverse applications that affect a variety of constituents. The USGS
disseminates streamgage data free to the public and responds to over 887 million requests on streamflows annually. Direct
users of streamgage data include a variety of agencies at all levels of government, private companies, scientific institutions,
and recreationists. Data from streamgages inform real-time decisionmaking and long-term planning on issues such as water
management and energy development, infrastructure design, water compacts, water science research, flood mapping and
forecasting, water quality, ecosystem management, and recreational safety.
Congress has provided the USGS with authority and appropriations to conduct surveys of streamflow since establishing the
first hydrological survey in 1889. Many streamgages are operated cooperatively with nonfederal partners, which approach the
USGS and sign joint-funding agreements to share the cost of streamgages and data collection. The USGS Cooperative
Matching Funds (CMF) Program provides up to a 50% federal match with tribal, regional, state, and local partners. The
average nonfederal cost-share contribution increased from approximately 50% in the early 1990s to approximately 69% in
FY2020. In the early 2000s, the USGS designated federal priority streamgage (FPS) locations based on five identified
national needs. The SECURE Water Act of 2009 (Title IX, Subtitle F, o f P.L. 111-11) directed the USGS to operate no fewer
than 4,700 federally funded streamgages by FY2019. In FY2020, 3,470 of the 4,760 FPSs designated by the USGS were
operational, with 35% of FPSs funded solely by the USGS FPS program funds and the rest funded by a combination of
federal and nonfederal funds.
Congressional appropriations and agreements with 1,400 nonfederal partners funded USGS streamgages at $194.9 million in
FY2020. The USGS share included $24.7 million for FPSs and $29.4 million for cooperative streamgages through CMF. A
dozen other federal agencies provided $38.0 million. Nonfederal partners, mostly affiliated with CMF, provided $102.8
million. In FY2021, Congress appropriated the same amount of funding as in FY2020 for FPS and CMF streamgages.
Congress apropropriated $24.5 million in FY2021 for the Next Generation Water Observing System (NGWOS), an effort to
establish dense water monitoring networks in representative watersheds in order to model streamflow in analogous
watersheds.
The USGS uses appropriated funding to develop and maintain the USGS Streamgaging Network. The USGS and numerous
stakeholders have raised funding considerations including user needs, priorities of partners, federal coverage, infrastructure
repair, disaster response, inflation, and technological advances. Some stakeholders advocate for maintaining or expanding the
network. Others may argue that Congress should consider reducing the network in order to prio ritize other activities and that
other entities operate streamgages tailored to localized needs. Congress might also consider whether to invest in streamgage
restoration and new technologies.
Congress may consider outlining the future direction for the USGS Streamgaging Network through oversight or legislation.
The USGS failed to meet a deadline set by the SECURE Water Act of 2009 to operate no fewer than 4,700 FPSs by FY2019.
Congress has provided level funding for FPSs while directing the USGS through appropriations legislation to increase
investment in the NGWOS. Congress may consider such policy options as pursuing both the FPS mandate and the NGWOS
simultaneously, amending the SECURE Water Act of 2009, and determining the relative emphasis of the NGWOS in the
agency’s streamgaging enterprise.
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Contents
Introduction ................................................................................................................... 1
What Is a Streamgage?..................................................................................................... 2
Streamgage Uses............................................................................................................. 5
Examples of Streamgage Uses ..................................................................................... 6
Network Structure ........................................................................................................... 9
Cooperative Matching Funds Program ........................................................................ 10
Federal Priority Streamgages ..................................................................................... 12
Next Generation Water Observing System ................................................................... 14
Network Funding .......................................................................................................... 15
USGS Funding Trends.............................................................................................. 17
Issues for Congress ....................................................................................................... 19
Funding Considerations ............................................................................................ 19
Addressing the Size of the Network ...................................................................... 19
Restoration of Streamgages.................................................................................. 22
Modernizing the USGS Streamgaging Network ...................................................... 23
Balancing Policy Options.......................................................................................... 26
Pursuing Both the FPS Mandate and the NGWOS ................................................... 26
Amending the SECURE Water Act of 2009 ............................................................ 27
Replacing the FPS Network with the NGWOS........................................................ 27


Figures
Figure 1. USGS Streamgaging Network Structure and Number of Streamgages ........................ 1
Figure 2. Diagram of a Streamgage Measuring Stream Stage Height ....................................... 3
Figure 3. Discharge Graph Capturing Streamflow During Hurricane Isaias .............................. 4
Figure 4. USGS Streamgage Informing Recreational Activities .............................................. 9
Figure 5. Number of National Streamflow Network Streamgages in U.S. States and
Territories in 2020 ...................................................................................................... 10
Figure 6. Number of USGS Streamgages and Policy Changes over Time ............................... 12
Figure 7. FY2020 Funding for the USGS Streamgaging Network ......................................... 15
Figure 8. USGS Funding for the Streamgaging Network ..................................................... 18
Figure 9. Map of the Next Generation Water Observing System (NGWOS) in the
Delaware River Basin ................................................................................................. 25

Tables
Table 1. FY2020 Funding and Streamgages Supported by Other Federal Agencies .................. 16

Contacts
Author Information ....................................................................................................... 28
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U.S. Geological Survey (USGS) Streamgaging Network: Overview and Issues for Congre


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Introduction
Streamgages measure water level and related streamflow at streams, rivers, lakes, and reservoirs
across the country. Streamgages provide foundational information for diverse applications that
affect a variety of constituents. Congress has supported a national streamgage program for over
130 years.1 These streamgages operate in every state, the District of Columbia, and the territories
of Puerto Rico and Guam. The widespread use of national streamgages and their operations
garner interest from many Members of Congress. Data from streamgages informs real-time
decisionmaking and long-term planning on issues such as hazard preparations and response,
infrastructure design, water use al ocations, ecosystem management, and recreation.2 Direct users
of streamgage data include a variety of agencies from al levels of government, utility companies,
consulting firms, scientific institutions, and recreationists.3
Streamgages are operated across the globe
with national programs in North America,
Figure 1. USGS Streamgaging Network
Europe, Australia, and Brazil, among others.4
Structure and Number of Streamgages
In the United States, the U.S. Geological
Survey (USGS), the Department of the
Interior’s (DOI’s) lead scientific agency,
manages the USGS Streamgaging Network
(Figure 1). The network encompasses
approximately 11,340 streamgages that record
water height or streamflow for at least a
portion of the year. Approximately 8,460 of
these streamgages measure streamflow year-
round and are part of the National Streamflow
Network. This subnetwork includes 3,470
Federal Priority Streamgages (FPSs), which
Congress and the USGS designated as
national priorities (see section on “Federal
Priority Streamgages”
). Some entities, such as

state governments, operate their own
Source: CRS with data from USGS Groundwater
streamgages separate from the USGS
and Streamflow Information Program.
Streamgaging Network.5
Notes: The National Streamflow Network is a
subset of the USGS Streamgaging Network, and
Congressional appropriations and agreements
Federal Priority Streamgages are a subset of the
with approximately 1,400 nonfederal partners
National Streamflow Network.

1 Congress has provided the U.S. Geological Survey (USGS) with the authority and appropriations to conduct surveys
of streamflow since establishing the first hydrological survey in 1889. 28 Stat. 910 funded the first irrigation survey to
be conducted by the USGS.
2 National Hydrologic Warning Council (NHWC), Benefits of USGS Streamgaging Program , 2006, at
https://water.usgs.gov/osw/pubs/nhwc_report.pdf. Hereinafter NHWC, Benefits of USGS Streamgaging Program.
3 T he Coalition Supporting the USGS National Water Monitoring Network, for example, which represents an array of
stakeholders (local agencies, river compact commissions, environmental nonprofits, professional societies, and
recreational groups), frequently advocates for USGS streamgage funding.
4 Albert Ruhi, Mathis L. Messager, and Julian D. Olden, “T racking the Pulse of the Earth’s Fresh Waters,” Nature
Sustainability
, vol. 1, no. 4 (2018), p. 199. Hereinafter Ruhi, Earth’s Fresh Waters.
5 Personal correspondence between CRS and Chad Wagner of the Groundwater and Streamflow Information Program,
USGS, November 30, 2020.
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funded the USGS Streamgaging Network at $194.9 mil ion in FY2020.6 Some streamgages are
funded solely through congressional appropriations for the USGS and other federal agencies,
such as the U.S. Army Corps of Engineers (USACE), Bureau of Reclamation (Reclamation), and
Department of Defense (DOD). Much of the USGS Streamgaging Network is funded
cooperatively. Interested parties sign funding agreements with the USGS to share the cost of
streamgages and data collection.7 The USGS Cooperative Matching Funds Program (CMF)
provides up to a 50% match with tribal, regional, state, and local partners (see section on
“Cooperative Matching Funds Program”).8 Other federal agencies, nonfederal governments, and
nongovernmental entities may provide reimbursable funding for streamgages in the USGS
Streamgaging Network without contributed funds from the USGS.9
Evolving federal policies and user needs from diverse stakeholders have shaped the size,
organization, and function of the USGS streamgage program. This report provides an overview of
federal streamgages by describing the function of a streamgage, the data available from
streamgage measurements, and the uses of streamgage information. The report also outlines the
structure and funding of the USGS Streamgaging Network and discusses potential issues for
Congress, such as funding priorities and the future structure of the nation’s streamgage network.
What Is a Streamgage?
A streamgage’s primary purpose is to collect data on water levels and streamflow (the amount of
water flowing through a river or stream over time).10 Streamgages estimate streamflow based on
(1) continuous measurements of stage height (the height of the water surface) and (2) periodic
measurements of streamflow, or discharge, in the channel and floodplains.11 USGS measurements
are used to create rating curves, in order to convert continuously measured stage heights into
estimates of streamflow.12 Selected streamgages may provide additional measurements, such as
measurements of water quality (see box on “Supergages”).
Streamgages house instruments to measure, store, and transmit stream stage height (Figure 2).13
Stage height is usual y transmitted every hour, or more frequently at 5 to 15 minute intervals for

6 Personal correspondence between CRS and Chad Wagner of the Groundwater and Streamflow Information Program,
USGS, November 30, 2020. T he appropriations bill for Interior, Environment, and Related Agencies funds the USGS
share of the USGS Streamgaging Network under the Groundwater and Streamflow Information Program.
7 Personal correspondence between CRS and Chad Wagner of the Groundwater and Streamflow Information Program,
USGS, April 9, 2019.
8 43 U.S.C. §50. “ T he share of the United States Geological Survey in any topographic mapping or water resources
data collection and investigations carried on in cooperatio n with any State or municipality shall not exceed 50 per
centum of the cost thereof.”
9 Personal correspondence between CRS and Chad Wagner of the Groundwater and Streamflow Information Program,
USGS, November 15, 2018.
10 T his section describes the basics of streamgaging specific to the USGS operations of continuously measuring
streamflow. Over 2,000 streamgages in the USGS Streamgaging Network only record water level or operate less than
year-round.
11 Stephen Blanchard, Recent Improvements to the U.S. Geological Survey from the National Streamflow Information
Program
, USGS, FS 2007-3080, 2007, at http://pubs.usgs.gov/fs/2007/3080/index.html.
12 Rating curves are relationships between stage height and streamflow. T he USGS develops rating curves using
streamflow measurements over range of stage heights.
13 Vernon Sauer and Phil T urnipseed, Stage Measurement at Gaging Stations, U.S. Geological Survey T echniques and
Methods Book 3, Chapter A7, 2010, at https://pubs.usgs.gov/tm/tm3-a7/.
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emergency or priority streamgages.14 Most streamgages transmit data by satel ite to USGS
computers; the data then are provided online to the public. 15 Numerous streamgages also have
cameras that capture and transmit photos of streamflow conditions.16
Figure 2. Diagram of a Streamgage Measuring Stream Stage Height

Source: Dee Lurry, How Does a U.S. Geological Survey Streamgage Work? USGS, FS 2011-3001, 2011, at
https://pubs.usgs.gov/fs/2011/3001/pdf/fs2011-3001.pdf.
Notes: This figure depicts a streamgage measuring stage height with a bubble system, but streamgages also may
measure stage height using other technology.
Periodic streamflow measurements require USGS personnel to measure discharge at various
sections across the stream.17 Streamflow measurements are made every six to eight weeks to
capture a range of stage heights and streamflows, especial y at high and low stage heights.
Repeated measurements al ow scientists to capture changes to the channel from vegetation
growth, sedimentation, or erosion, which can affect the relationship between stage height and
streamflow.
The USGS National Water Information System (NWIS) receives and converts stream height data
from USGS streamgages into streamflow estimates.18 An example of streamgage data from NWIS
is shown in Figure 3 for a site capturing peak streamflow during a hurricane event. The free and

14 J. Michael Norris, From the River to You: USGS Real-Time Streamflow Information, USGS, FS 2007-3043, 2007, at
https://pubs.usgs.gov/fs/2007/3043/.
15 Streamgages are increasingly employing cellular and radio telemetry as an additional way to transmit and serve data
online. Personal correspondence between CRS and Chad Wagner of the Groundwater and Streamflow Information
Program, USGS, February 19, 2019.
16 An example of a streamgage camera can be accessed at https://ca.water.usgs.gov/webcams/.
17 Phil T urnipseed and Vernon Sauer, Discharge Measurements at Gaging Stations, U.S. Geological Survey
T echniques and Methods Book 3, Chapter A8, 2010, at https://pubs.usgs.gov/tm/tm3-a8/.
18 T he USGS Surface-Water Data for the Nation, National Water Information System: Web Interface houses
streamgage data at https://waterdata.usgs.gov/nwis. Users may select various USGS monitoring sites across the United
States to access streamflow and other field measurements using USGS National Water Information System: Mapper at
https://maps.waterdata.usgs.gov.
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publicly accessible data are frequently accessed online or by request to users.19 For example, in
FY2020, there were 52.3 mil ion visits to the NWIS website and NWIS responded to over 887
mil ion human and automated requests for streamflow and water level information.20 The NWIS
website is the main repository for current and historical streamflow data, in addition to other
water information. Tools such as WaterWatch summarize the current conditions of the nation’s
streams and watersheds through maps, graphs, and tables by comparing real-time streamflow
conditions to historic streamflow from streamgages with records of 30 years or more.21
Figure 3. Discharge Graph Capturing Streamflow During Hurricane Isaias

Source: USGS, Water Data for Maryland, at https://waterdata.usgs.gov/md/nwis.
Notes: The discharge graph is derived from a streamgage capturing a spike in streamflow during Hurricane
Isaias. The USGS may sometimes measure discharge onsight by hand (red shape) during such events to validate
streamgage data and improve rating curves that estimate discharge based on stage height. The vertical axis
showing discharge is a logarithmic scale.

19 Users can send an email or text to receive instant information about a specific streamgage with USGS WaterNow
(accessible at https://water.usgs.gov/waternow), or they can sign up to receive alerts about stream conditions with
USGS WaterAlert (accessible at https://maps.waterdata.usgs.gov/mapper/wateralert/). Other partnership applications
using Geographic Information System (GIS) interfaces include StreamStats (accessible at https://streamstats.usgs.gov),
and T X Water on the Go and T X Water Dashboard (accessible at https://waterdata.usgs.gov/tx/nwis/rt).
20 Personal correspondence between CRS and Chad Wagner of the Groundwater and Streamflow Information Program,
USGS, November 30, 2020.
21 USGS WaterWatch is accessible at https://waterwatch.usgs.gov.
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Streamgage Uses
The USGS Streamgaging Network provides streamflow information to assist during natural and
man-made disasters, such as flooding and drought, and to inform economic and statutory water
management decisions, such as the al ocation of water supplies for irrigation. Individual
streamgages in the network also can serve multiple uses. For example, a streamgage intentional y
established for the purpose of reservoir management may provide data to inform water quality
standards, habitat assessments, and recreational activities.22 Additional y, the value of a single
streamgage is enhanced by the operation of the entire network, particularly for research,
modeling, and forecasting.
Streamgages were first established in the United States to inform water use and infrastructure
planning—applications that benefit from continuous, long-term hydrologic records (see box on
“Evolution of Streamgage Uses”).23 Long and continuous periods of data are used to construct
baselines for water conditions and to identify deviations in the amount and timing of streamflow
caused by changes in land use, water use, and climate.24 Some stakeholders contend that the value
of streamflow records increases over time, with at least 20 years of continuous coverage needed
for many applications.25
Evolution of Streamgage Uses
A decade after the establishment of the U.S. Geological Survey
(USGS) in 1879, Congress directed the USGS to conduct a
hydrographic survey to measure streamflow of arid basins in the
West. The survey was to investigate sites for reservoirs and other
hydraulic works for the dual purpose of water storage for irrigation
and flood prevention. The first station was on the Rio Grande in
New Mexico. Since 1895, Congress has provided annual
appropriations for streamgage surveys.
By 1900, there were 163 streamgages, mostly located in the West
and operated for the purposes of monitoring water use and
availability for irrigation. An expansion of the streamgage program
began in the 20th century. The early drivers for expansion were the
need of streamgage information to enhance water withdrawal and
use, navigation, hydropower production, construction of military
and transportation infrastructure, and flood risk and mitigation.
Toward the end of the 20th century, water quality monitoring,
regulations of streamflow for wildlife and fisheries habitat, and
recreational decisionmaking further underpinned the need for
streamflow information.
In the 21st century, these streamgage applications remain pertinent
with the addition of more novel focuses: integration of
groundwater-surface water interactions; forecasting the effects of

22 NHWC, Benefits of USGS Streamgaging Program.
23 Kenneth Wahl, Wilbert T homas, and Robert Hirsch, Overview of the Stream -gaging Program, USGS, Circular 1123,
Reston, VA, 1995, at https://pubs.usgs.gov/circ/circ1123/overview.html. Hereinafter Wahl, USGS Circular 1123.
24 Eric J. Evenson et al., Continuing Progress Toward a National Assessment of Water Availability and Use,
Department of the Interior (DOI), Circular 1440, 2018, p. 23, at https://pubs.usgs.gov/circ/1440/circ1440.pdf.
Hereinafter Evenson, DOI National Water Assessment.
25 Personal correspondence between CRS and Sue Lowry of the Interstate Council on Water Policy, November 16,
2018. John Schaake, Qingyun Duan, and Michael Smith, et al., “ Criteria to Select Basins for Hydologic Model
Development and T esting,” 15th Conference on Hydrology, American Meteorological Society, Long Beach, CA, 2000.
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hazards, especial y in areas without streamgages; and modeling human interaction and prediction of water
resources with increased land use, population gains, and climate change.
Notes: Photo depicts a hydrographer taking a cableway streamflow measurement at the first USGS streamgage.
USGS, “The History of the HIF,” at https://www.usgs.gov/labs/hif/about/history-hif.
Technological advances al owing access to streamflow information in real time have expanded
the uses of streamgages. Real-time forecasting and operational decisionmaking are used in many
applications of streamflow data.26 Web and phone applications also have facilitated increased
public use of water information.27
Examples of Streamgage Uses
Streamgage data is used for a wide range of applications, including supporting activities of
federal agencies. There are also a variety of streamgages tailored for specific purposes. The
following is a noncomprehensive selection of streamgage uses to il ustrate the scope of
applications.
Water Management and Energy Development. USACE, Reclamation, and various state and
local water management agencies use streamgages to inform the design and operation of
thousands of water management projects across the nation.28 Timely streamflow information
helps water managers make daily operational decisions as they balance water requirements for
municipal, industrial, and agricultural uses. Energy production and mineral extraction operations
also rely on continuous streamflow measurements to comply with environmental, water quality,
or temperature requirements.29 For example, the Federal Energy Regulatory Commission (FERC)
requires hydropower companies to support streamflow and water-level monitoring as part of their
FERC licensing process.30
Infrastructure Design. Transportation agencies use streamflow data to develop regional flow
frequency curves for the design of bridges and culverts, stream stability measurements, and
analysis of bridge scour—the leading cause of bridge failure.31 Without adequate information,
some observers contend that engineers may overdesign structures, resulting in greater costs, or
may not make proper al owances for floods, compromising public safety.32
Interstate and International Water Rights. Federal streamgages are used to col ect streamflow
information at U.S. borders and between states.33 Streamgage data informs interstate compacts,
Supreme Court decrees, and international treaties (e.g., treaties under the purview of the
International Boundary and Water Commission and the International Joint Commission).
Water Science Research. Many federal agencies depend on consistent, long-term data from
streamgages to conduct water research and modeling (e.g., USACE, National Oceanic and

26 NHWC, Benefits of USGS Streamgaging Program.
27 USGS, Budget Justifications and Performance Information, Fiscal Year 2017 , J - Water Resources.
28 NHWC, Benefits of USGS Streamgaging Program.
29 Wahl, USGS Circular 1123.
30 T he Federal Energy Regulatory Commission (FERC) licenses the construction and operation of nonfederal
hydropower project pursuant to the Federal Power Act of 1935, 16 U.S.C. §797(a)(c).
31 Bridge scour is the removal of sediment from the base of bridge structures. NHWC, Benefits of USGS Streamgaging
Program, p. 8.
32 NHWC, Benefits of USGS Streamgaging Program, p. 8.
33 NHWC, Benefits of USGS Streamgaging Program, p. 12.
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Atmospheric Administration [NOAA], Environmental Protection Agency [EPA], DOI, U.S.
Department of Agriculture [USDA], and National Aeronautic and Space Administration
[NASA]).34 To monitor climate trends and ecological patterns, the USGS distinguishes a subset of
streamgages that are largely unaffected by development to serve as benchmarks for natural
conditions.35
National Water Model
The National Oceanic and Atmospheric Administration’s National Weather Service, in partnership with other
agencies, launched the National Water Model in 2016. The National Water Model forecasts streamflow over the
conterminous United States in near real time. The model assimilates real-time observations from more than 6,780
U.S. Geological Survey (USGS) streamgages in addition to inputs of precipitation and land-surface properties. The
model provides streamflow forecasts with 18-hour, 10-day, and 30-day lead times for 2.7 mil ion streams and
rivers across the nation. In addition to high flows and flooding, the model also captures low flows and drought
conditions. An updated version to be released in 2021 is to include enhanced streamflow forecasts of 5,783 lakes
and resevoirs and expanded coverage to the Great Lakes drainage basin, Puerto Rico, and Hawai . Future
iterations of the model may include expanded coverage in Alaska and improved runoff and coastal hydrology
modeling. The National Water Model builds off of the USGS National Hydrologic Model, which couples
precipitation, surface water, and groundwater interactions.
Source: National Oceanic and Atmospheric Administration (NOAA), National Water Model: Improving NOAA’s
Water Prediction Services
, 2016, at http://water.noaa.gov/documents/wrn-national-water-model.pdf; Brian A.
Cosgrove, NOAA, NOAA’s National Water Model: From V2.1 Operations to Future Enhancements in V3.0, American
Geophysical Union, 2020 Fal Conference.
Flood Mapping. The Federal Emergency Management Agency (FEMA) uses floodplain maps to
establish flood risk zones and requires flood insurance through the National Flood Insurance
Program (NFIP) for properties with a 1% annual chance of flooding.36 Long-term streamflow
records are used to determine 1% annual chance flood flows and to develop water surface profiles
to map areas at risk of flooding. The USGS often works with FEMA to produce new inundation
maps after streamgages record new streamflow peaks from weather events such as hurricanes.37
Emergency Forecasting and Response. Streamgages inform flood forecasting and emergency
response to protect lives and property.38 Real-time data from more than 6,780 streamgages al ow
NOAA’s National Weather Service (NWS) river forecasters to model watershed response, project
future streamflows, forecast monthly to seasonal water availability, and issue appropriate flood
watches and warnings (see box on “National Water Model”).39 Flood warnings provide lead time

34 Advances in satellite observations also depend on streamgages to calibrate stream discharge models. National
Academies of Sciences, Engineering, and Medicine (NASEM), Future Water Priorities for the Nation: Directions for
the U.S. Geological Survey Water Mission Area
, Washington, DC, 2018, pp. 8 and 66, at https://doi.org/10.17226/
25134. Hereinafter NASEM, Future Water Priorities for the Nation.
35 T hese are referred to as sentinel basins, according to the National Research Council (NRC), Assessing the National
Stream flow Inform ation Program
, pp. 57-59, at https://doi.org/10.17226/10967. Hereinafter NRC, Assessing the NSIP.
36 41 U.S.C. §§4011 et seq. See CRS Report R44593, Introduction to the National Flood Insurance Program (NFIP),
by Diane P. Horn and Baird Webel. Because the 1% annual exceedance probability flood has a 1 in 100 chance of
being equaled or exceeded in any one year and an average recurrence interval of 100 years, it often is referred to as the
100-year flood. Robert R. Holmes, “ T he 100-Year Flood - It’s All About Chance,” USGS, at https://water.usgs.gov/
edu/100yearflood-basic.html.
37 Kara Watson et al., Characterization of Peak Streamflows and Flood Inundation of Selected Areas in Southeastern
T exas and Southwestern Louisiana from the August and September 2017 Flood Resulting from Hurricane Harvey,
USGS, Scientific Investigations Report 2018–5070, 2018, at https://doi.org/10.3133/sir20185070.
38 William J. Carswell and Vicki Lukas, The 3D Elevation Program – Flood Risk Management, USGS, FS 2017-3081,
2018, at https://doi.org/10.3133/fs20173081.
39 T he Secretary of Commerce is charged with flood warning and reporting on river conditions pursuant to the National
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for emergency response agencies, such as FEMA, to take effective action in advance of rising
waters.40 In addition, the USDA National Resource Conservation Service (NRCS) uses
streamgages to forecast flows for water supply, drought management and response, hydroelectric
production, irrigation, and navigation in western states.41
Rapid Deployment Gages
Rapid deployment gages (RDGs) are temporarily fixed
on structures above streams and rivers (such as
bridges) in emergencies to add stage height data when
a streamgage does not exist or is damaged. Water-
stage height and meteorological conditions are
transmitted every six minutes. The U.S. Geological
Survey (USGS) Flood Event Viewer provides a website
where streamgage and RDG data can be seen in real
time for large flood events. The USGS had 182 RDGs
in 2020 and deployed 47 during Hurricane Dorian in
2019.
Source: USGS, Rapid Deployment Gages, at
https://water.usgs.gov/floods/resources/rdg, and Flood
Event Viewer
, at https://stn.wim.usgs.gov/FEV.

Notes: This fixed design can also be used for
permanent streamgages.
Water Quality. Streamflow data is important for measuring water quality and developing water
quality standards for sediments, pathogens, metals, nutrients (e.g., nitrogen and phosphorus), and
organic compounds (e.g., pesticides). At select streamgages, the USGS also operates instruments
recording water quality data (see box on
“Supergages”). Section 303(d) of the Clean
Supergages
Water Act requires states to develop total
Supergages are a smal subset of streamgages (just over
maximum daily load (TMDL) management
510) that col ect chemical data in addition to
plans for water bodies determined to be water
streamflow by using water quality monitoring
equipment. Supergages monitor continuous streamflow
quality impaired by one or more pollutants.42
in addition to either (1) a combination of physical
When determining TMDL levels for specific
parameters, such as temperature, conductance, pH,
pollutants, agencies may consider historic
dissolved oxygen, turbidity, or dissolved organic
streamflow data, along with other factors, in
matter, or (2) one or more measurements of nitrate,
phosphorus, suspended sediment, chlorophyl , or
their evaluations. Agencies may use current
cyanobacteria data. The information from supergages is
flow conditions when determining the proper
used for decisionmaking regarding drinking water,
release of wastewater to ensure compliance
water treatment, regulatory programs, recreation,
with TMDL standards and National Discharge
public safety, and ecosystem health.
Elimination System permitting.43

Weather Service Modernization Act of 1890, 15 U.S.C. §313 et seq. Personal correspondence between CRS and Chad
Wagner of the Groundwater and Streamflow Information Program , USGS, November 30, 2020.
40 National Hydrologic Warning Council, Flood Management Benefits of USGS Streamgaging Program , 2006, pp. 25-
33, at https://water.usgs.gov/osw/pubs/Flood_Management_benefits_complete.pdf.
41 NRC, Assessing the NSIP, pp. 4 and 55.
42 A T MDL is both a quantitative assessment of pollution sources and pollutant reductions needed to restore and protect
U.S. waters and a planning process for attaining water quality standards.
43 NHWC, Benefits of USGS Streamgaging Program, p. 11.
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Ecosystem Management and Species. Some water users and resource agencies use streamflow
data to meet the flow requirements needed to protect endangered or threatened fish and wildlife
under the Endangered Species Act (16 U.S.C. §1531 et seq.). Natural resource agencies, such as
the U.S. Fish and Wildlife Service (FWS), collect streamflow data to understand how threatened
and endangered species respond to flow variations.44 The USGS operates streamgages to monitor
ecosystem restoration progress, such as restoration of the Chesapeake Bay watershed.45
Recreation. Real-time streamgage data can help individuals and tourism businesses assess stream
conditions for recreational outings.46 USGS data can be used to decide if conditions are suitable
for recreational activities such as fishing, boating, and rafting (see Figure 4). The USGS also
partners with the National Park Service (NPS) to provide water science and data to help manage
parks and to enhance interpretive programs.
Figure 4. USGS Streamgage Informing Recreational Activities

Source: Photo by Edward Gertler.
Notes: The streamgage (https://waterdata.usgs.gov/nwis/uv?site_no=01619500) in the left-facing part of the
photo helps inform recreational paddling, among other uses, in Antietam Creek, which flows through Antietam
National Battleground.
Network Structure
The USGS Streamgaging Network is part of the Groundwater and Streamflow Information
Program under the USGS Water Resources mission area.47 The primary operators of streamgages

44 NHWC, Benefits of USGS Streamgaging Program, p. 10.
45 Scott Phillips et al., U.S. Geological Survey Chesapeake Science Strategy, 2015 -2025—Informing Ecosystem
Management of America’s Largest Estuary
, USGS, Open-File Report 2015–1162, 2015, at https://doi.org/10.3133/
ofr20151162.
46 NHWC, Benefits of USGS Streamgaging Program, p. 14.
47 USGS, Budget Justifications and Performance Information: Fiscal Year 2019 , pp. 79-93, at https://prd-wret.s3.us-
west-2.amazonaws.com/assets/palladium/production/atoms/files/
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are the regional and state USGS Water Science Centers, which maintain hydrologic data
collection and conduct water research in the region.48
Approximately 8,460 of the 11,340 USGS streamgages measure year-round streamflow (National
Streamflow Network; see Figure 5), with the rest only measuring stage height or streamflow on a
seasonal basis.49 USGS streamgages are also differentiated based on cooperative funding (CMF)
and federal interest (FPSs).
Figure 5. Number of National Streamflow Network Streamgages in U.S. States and
Territories in 2020

Source: CRS with data from the USGS Groundwater and Streamflow Information Program.
Notes: Streamgages in the National Streamflow Network measure streamflow year-round. Streamgages that
measure stage height only or operate seasonal y are not included in this figure.
Cooperative Matching Funds Program
Much of the streamgaging program has been cooperative in nature as interested parties sign
funding agreements to share the cost of streamgages and data collection.50 Through CMF, the

FY2019%20USGS%20Budget%20Justification%20%28Greenbook%29.pdf .
48 A list of USGS Water Science Centers can be found at https://www.usgs.gov/mission-areas/water-resources/about/
water-resources-mission-area-science-centers-and-regions.
49 Personal correspondence between CRS and Chad Wagner of the Groundwater and Streamflow Information Program,
USGS, November 30, 2020.
50 U.S. Government Accountability Office, Environmental Information, Status of Federal Data Programs that Support
Ecological Indicators
, 05-376, 2005, pp. 164-174, https://www.gao.gov/new.items/d05376.pdf. Hereinafter GAO,
Federal Data Programs.
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USGS funds up to a 50% match with tribal, regional, state, and local partners.51 In FY2020, CMF
partial y supported 5,273 streamgages (46% of the gages in the USGS Streamgaging Network).52
The first cooperative agreement began in 1895 with the Kansas Board of Irrigation Survey and
Experiment (now known as the Division of Water Resources of the Kansas Department of
Agriculture).53 Funds from cooperative entities steadily increased in the early 20th century.54
Congress passed legislation in 1928 stipulating that the USGS can share up to 50% of the costs
for water resources investigations carried out in cooperation with tribes, states, and municipalities
(see Figure 6).55 In 2016, this Federal-State Cooperative Water Program was renamed the
Cooperative Matching Funds Program (CMF), which provides cooperative funding for programs
across the USGS Water Mission Area.56
To participate in the CMF, potential partners approach the USGS to discuss the need for a specific
streamgage. The USGS determines its feasibility based on available funds and program priorities.
If the USGS deems establishing the streamgage is feasible, the USGS and cooperator sign a joint
funding agreement (JFA), which is a standard agreement that specifies how much each party wil
contribute to funding the streamgage and the payment schedule for the cooperator.57 These
agreements span five years or less. During the agreement, the cost-share general y remains the
same, but there is flexibility to alter the cost-share on an annual basis for multi-year agreements.
Once a streamgage is operating, if a partner can no longer contribute funds, the USGS seeks to
work with other partners that use the streamgage to augment funding. The USGS provides a
website identifying streamgages that are in danger of being discontinued or converted to a
reduced level of service due to lack of funding.58 The website also identifies streamgages that
have been discontinued or are being supported by a new funding source.
Approximately 3,900 of the 11,340 USGS streamgages (35%) are funded by nonfederal and
federal partners without matching funds from the USGS (i.e., not with CMF).59 Nonfederal
partners sign JFAs, and federal partners share interagency agreements with the USGS (except
USACE which uses a military interdepartmental purchase request).60 These gages are part of the
USGS Streamgaging Network and are operated in accordance with the quality control and public

51 43 U.S.C. §50. “ T he share of the United States Geological Survey in any topographic mapping or water resources
data collection and investigations carried on in cooperation with any State or municipality shall not exceed 50 per
centum of the cost thereof.”
52 Personal correspondence between CRS and Chad Wagner of the Groundwater and Streamflow Information Program,
USGS, November 30, 2020.
53 Wahl, USGS Circular 1123.
54 Mary Rabbitt, A Brief History of the U.S. Geological Survey, USGS, DOI 10.3133/70039204, Washington, DC,
1975.
55 P.L. 70-100.
56 USGS, Budget Justifications and Performance Information, Fiscal Year 2016, J - Water Resources, https://prd-
wret.s3.us-west-2.amazonaws.com/assets/palladium/production/atoms/files/
FY2016%20USGS%20Budget%20Justification%20%28Greenbook%29.pdf . Hereinafter USGS, FY2016 Budget.
57 Personal correspondence between CRS and Chad Wagner of the Groundwater and Streamflow Informat ion Program,
USGS, April 9, 2019.
58 Discontinued, threatened, or revived streamgages can be explored through an interactive map at
https://water.usgs.gov/networks/fundingstability.
59 Personal correspondence between CRS and Chad Wagner of the Groundwater and Streamflow Information Program,
USGS, November 30, 2020.
60 Personal correspondence between CRS and Chad Wagner of the Groundwater and Streamflow Information Program,
USGS, April 9, 2019.
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access standards created by the USGS, with the agency assuming liability responsibility for the
streamgages.
Public and private entities may also elect to own and operate streamgages tailored to their specific
needs and not affiliated with the USGS. These independent streamgages may differ in various
ways compared to streamgages in the USGS Streamgaging Network (e.g., capital and operating
costs, operating periods, measurement capabilities, and data standards and platforms).61
Figure 6. Number of USGS Streamgages and Policy Changes over Time

Source: CRS, with data from the USGS Groundwater and Streamflow Information Program.
Notes: This historic length-of-record dataset considered any USGS streamgage to be active in a given year if it
computed at least one daily value in that year. This dataset also includes streamgages in al surface-water bodies,
not just streams and lakes (i.e., wetlands, estuaries, drainage ditches, etc.). Therefore, the total streamgages in
this dataset include more than those in the USGS Streamgaging Network.
Federal Priority Streamgages
The SECURE Water Act of 2009 (Title IX, Subtitle F of P.L. 111-11) directed the USGS to
operate a reliable set of federal y funded streamgages. The law required the USGS to fund no
fewer than 4,700 sites complete with flood-hardened infrastructure, water quality sensors, and
modernized telemetry by FY2019. Original y titled the National Streamflow Information Program
(NSIP), the USGS now designates these streamgages as FPSs.62 Out of the 4,760 FPS locations

61 Personal correspondence between CRS and Chad Wagner of the Groundwater and Streamflow Information Program,
USGS, December 17, 2018.
62 USGS, FY2016 Budget.
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identified by the USGS, 3,470 sites (73%) were operational in FY2020.63 In FY2020, the USGS
share of funding was $24.7 mil ion for FPSs.
The idea of a federal y sustained set of streamgages arose in the late 20th century when audits
revealed the number of streamgages declining after peaking in the 1970s (see decrease in Figure
6
).
64 In a 1998 report to Congress, the USGS stated that the streamgage program was in decline
because of an absolute loss of streamgages, especial y those with a long record, and asserted that
the loss was due to partners discontinuing funding. Partner needs for streamflow information also
had evolved.65 In 1999, the USGS proposed the creation of an entirely federal y funded NSIP to
ensure a stable backbone network of streamgages to meet national needs.66 The USGS used five
national needs to determine the number and location of these streamgage sites:67
1. Meeting legal and treaty obligations on interstate and international waters.
2. Forecasting flow for NWS and NRCS.
3. Measuring river basin outflows to calculate regional water balances.
4. Monitoring benchmark watersheds for long-term trends in natural flows.
5. Measuring flow for water quality needs.
The original design included 4,300 active, previously discontinued, or proposed streamgage
locations.68 The proposed program was to be fully federal y funded, conduct intense data
collection during floods and droughts, provide regional and national assessments of streamflow
characteristics, enhance information delivery, and conduct methods development and research.69
The SECURE Water Act of 2009 authorized the NSIP to conform to the USGS plan as reviewed
by the National Research Council.70 The law required the program to fund no fewer than 4,700
sites by FY2019. The law also directed the program to determine the relationship between long-
term streamflow dynamics and climate change, to incorporate principals of adaptive management
to assess program objectives, and to integrate data collection activities of other federal agencies
(i.e., NOAA’s National Integrated Drought Information System) and appropriate state water
resource agencies.

63 When the USGS proposed FPS locations in the early 2000s, many sites were already operational. NRC, Assessing
the NSIP, p. 1. Personal correspondence between CRS and Chad Wagner of the Groundwater and Streamflow
Information Program, USGS, November 30, 2020.
64 For example, see Wahl, USGS Circular 1123. In 1998, the House Committee on Appropriations stated in report
language accompanying H.R. 4193 from the 105th Congress: “ the Committee has noted the steady decline in the
number of streamgaging stations in the past decade, while the need for streamflow data for flood forecasting and long-
term water management uses continues to grow.”
65 USGS, A New Evaluation of the USGS Streamgaging Network: A Report to Congress, 1998, at
https://water.usgs.gov/streamgaging/report.pdf.
66 USGS, Streamflow Information for the Next Century - A Plan for the National Streamflow Information Program of
the U.S. Geological Survey, 1999, OFR 99 -456, at https://pubs.usgs.gov/of/1999/ofr99456/.
67 Federal Priority Streamgages designated by specific national priorities may be visualized with an interactive map at
https://water.usgs.gov/networks/fps/.
68 T he number of FPS locations changes over time based on network analyses. In 2020, 4,760 locations met the criteria
for FPS designation. Personal correspondence between CRS and Chad Wagner of the Groundwater and Streamflow
Information Program, USGS, November 30, 2020.
69 NRC, Assessing the NSIP, p. 2.
70 SECURE Water Act of 2009 (T itle IX, Subtitle F of the Omnibus Public Land Management Act of 2009 [P.L. 111-
11]). NRC, Assessing the NSIP.
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Next Generation Water Observing System
In 2018, the USGS initiated a Next Generation Water Observing System (NGWOS) “to provide
high-fidelity, real-time data on water quantity, quality and use necessary to support more accurate
national modern water prediction and decision support systems and rapid and informed hazards
response.”71 The USGS plans to develop dense networks of streamgages and other monitoring
systems in up to 10 medium-sized watersheds (each approximately 15,000 square miles), each
one representative of a larger water-resource region. Existing monitoring networks, such as the
FPS, are at fixed locations to address specific critical needs, as authorized by the Secure Water
Act. Within NGWOS watersheds, new and enhanced monitoring stations are to include some
streamgages at additional fixed locations to fil critical gaps in the basins selected. They also are
to include mobile monitoring stations, including remote sensing, which would al ow for more
flexibility in gathering information to improve understanding and predictions of water availability
at local, regional, and national scales.72 According to some stakeholders, the NGWOS also serves
as an innovation incubator for water-observing instrumentation and methods to improve the
efficiency, accuracy, and spatial and temporal scales of data collection.73 Success of new
monitoring technology in these basins may lead to their incorporation into the routine operation
of USGS monitoring networks.
If fully implemented, the NGWOS would provide quantitative information on streamflow,
snowpack, loss of water to the atmosphere, soil moisture, water quality, groundwater, and water
usage. The USGS contends that a suite of highly monitored watersheds, in combination with an
enhanced streamgage network and other relevant data sets, can better inform complex models
(e.g., the National Water Model) and streamflow information and forecasts. To assess this
approach, the USGS started a multiyear NGWOS pilot in the Delaware River Basin in FY2018.
Since then, the USGS has selected two additional basins for NGWOS implementation: the Upper
Colorado River Basin was selected in FY2020,74 and the Il inois River Basin was selected in
FY2021.75 The USGS plans to instal new or updated streamgages and other monitoring stations
in these basins. Many of these streamgages are to be equipped with two-way communication for
remote operation and troubleshooting, cel and satel ite transmission redundancy, webcams, and
water-quality sensors.

71 USGS, Next Generation Water Observing System: Delaware River Basin, 2018, at https://www.usgs.gov/mission-
areas/water-resources/science/next -generation-water-observing-system-delaware-river-basin.
72 T he USGS states that the Next Generation Water Observing System (NGWOS) is not a replacement for existing
networks, such as the FPS; rather, the NGWOS relies and builds upon the strength of existing m onitoring networks.
Personal correspondence between CRS and Chad Wagner of the Groundwater and Streamflow Information Program ,
USGS, November 30, 2020.
73 T echnologies of interest include radar and image velocimetry for remotely sensing surface-water velocities, drone-
mounted ground-penetrating radar for measuring bathymetry for improving flow estimates, new sensors for monitoring
continuous water-quality and suspended sediment, and others. Personal correspondence between CRS and Chad
Wagner of the Groundwater and Streamflow Information Program, USGS, November 30, 2020.
74 USGS, Next Generation Water Observing System: Upper Colorado River Basin , 2019, at https://www.usgs.gov/
mission-areas/water-resources/science/next -generation-water-observing-system-upper-colorado-river?qt-
science_center_objects=0#qt -science_center_objects.
75 USGS, Next Generation Water Observing System: Illinois River Basin, 2020, at https://www.usgs.gov/mission-areas/
water-resources/science/next -generation-water-observing-system-illinois-river-basin?qt-science_center_objects=0#qt -
science_center_objects.
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Network Funding
In FY2020, congressional appropriations and nonfederal partners provided $194.9 mil ion for the
USGS Streamgaging Network (Figure 7).76 The USGS share included $24.7 mil ion for FPSs and
$29.4 mil ion for CMF. Other federal agencies provided $38.0 mil ion (Table 1). Nonfederal
partners, mostly affiliated with the CMF program, provided $102.8 mil ion in FY2020.
Figure 7. FY2020 Funding for the USGS Streamgaging Network
(in thousands of dol ars)

Source: CRS, with data from the USGS Groundwater and Streamflow Information Program.
Notes: Other nonfederal funding includes commercial businesses, nonprofit organizations, or power companies
requiring streamflow data as part of their FERC licensing process.

76 T otal funding for the USGS Streamgaging Network is determined at the end of the fiscal year after accounting for
contributions from cooperative partners. Personal correspondence between CRS and Chad Wagner of the Groundwater
and Streamflow Information Program, USGS, November 30, 2020.
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The appropriations bil for the Interior,
Approximate Cost of
Environment, and Related Agencies funds the
USGS Streamgages
USGS share of the USGS Streamgaging
Network. Funding for streamgages is included
Capital costs for equipment and instal ation:
in the Groundwater and Streamflow

$25,000 - $40,000 for a standard streamgage
Information Program under the USGS Water
depending on the site conditions.
Resources Mission Area. The line item

$35,000 - $110,000 for a supergage depending on
sensors and the site conditions.
includes funding for the streamgage network
and groundwater monitoring activities, as wel

$15,000 for RDGs.
as other activities.77 Congress provided $84.2
Annual costs for operation and maintenance:
mil ion in FY2020 and $100.7 mil ion in

$16,500 - $32,000 for continuous streamflow
FY2021 for the Groundwater and Streamflow
measurements with a standard streamgage
depending on site conditions. Costs decrease by
Information Program.78 Congress directed $16
half if measuring stream stage height only and
mil ion of the $16.5 mil ion increase for
proportional y if measuring seasonal y.
FY2021 to the NGWOS.79 Funding for FPS

$26,000 and $135,000 for supergages depending
and cooperative streamgages remained level in
on site conditions and the type and number of
FY2021 compared with FY2020.
sensors.

Other federal agencies contribute to whole or

$4,000 per event for RDGs.
partial funding of streamgages for agency
purposes (Table 1). Since FY2012, funding from other federal agencies has nearly doubled from
$19.9 mil ion to $38.0 mil ion in nominal dollars. This increase may be due to meeting inflation
and other streamgage cost increases, to new needs for monitoring data with existing cooperators
(e.g., USACE in the Savannah and Jacksonvil e Harbor expansion projects), and to the
introduction of additional funding partners (e.g., the EPA) that are supporting new streamgages.80
Table 1. FY2020 Funding and Streamgages Supported by Other Federal Agencies
Funding
Agency
(millions)
Streamgages
U.S. Army Corps of Engineers
$26.00
2,189
Bureau of Reclamation
$4.93
310
Department of Defense (not civil)
$1.38
75
Bureau of Land Management
$1.03
65
Department of State
$0.93
103
U.S. Fish and Wildlife Service
$0.73
31

77 T he President’s budget requests for FY2020 and FY2021 proposed creating a new Water Observing Systems
Program combining the Groundwater and Streamflow Information Program and elements of the National Water Quality
program focused on observations of surface water and groundwater. Congress did not adopt this proposal in either
fiscal year. USGS, Budget Justifications and Perform ance Inform ation: Fiscal Year 2020 , at https://prd-wret.s3.us-
west-2.amazonaws.com/assets/palladium/production/atoms/files/fy2020_usgs_budget_justification.pdf. USGS, Budget
Justifications and Perform ance Inform ation: Fiscal Year 2021
, https://prd-wret.s3.us-west-2.amazonaws.com/assets/
palladium/production/atoms/files/fy2021-usgs-budget-justification.pdf. Explanatory statements accompanying Division
D of P.L. 116-94 and Division G of P.L. 116-260.
78 Explanatory statements accompanying Division D of P.L. 116-94 and Division G of P.L. 116-260.
79 Division E of H.Rept. 116-9 accompanying P.L. 116-6.
80 T he Environmental Protection Agency (EPA) is supporting ecosystem restoration initiatives in the Great Lakes,
Chesapeake Bay, and the Sacramento and San Joaquin Rivers Delta (Bay -Delta) in California. Personal correspondence
between CRS and Chad Wagner of the Groundwater and Streamflow Information Program, USGS, February 19, 2019.
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Funding
Agency
(millions)
Streamgages
National Park Service
$0.72
39
Environmental Protection Agency
$0.66
87
Department of Energy
$0.62
39
Tennessee Val ey Authority
$0.47
33
U.S. Department of Agriculture
$0.35
21
(USDA)
Bureau of Indian Affairs
$0.13
13
Source: CRS, with data from the USGS Groundwater and Streamflow Information Program.
Notes: Department of State funding included 86 streamgages for the International Joint Commission (Canadian
border) and 17 streamgages for the International Boundary and Water Commission (Mexican border). USDA
funding included streamgages from National Resource Conservation Service and the U.S. Forest Service. FY2021
data are not yet available at the time of publication.
Nonfederal partners funded approximately half the costs of the USGS Streamgaging Network
from FY2012 to FY2020.81 Cooperative partners include tribal, regional, state, and local agencies
related to natural resources, water management, environmental quality, transportation, and
regional and city planning. Irrigation districts, riverkeeper partnerships, and utility agencies and
companies also fund the program. Contributions by nongovernmental partners to streamgages are
limited (4.5% in FY2020) and are not eligible for cost-sharing through the USGS CMF
program.82
USGS Funding Trends
From FY2003 to FY2021, USGS funding for FPS streamgages increased from $12.0 mil ion to
$26.2 mil ion (in 2019 dollars; Figure 8).83 Funding for FPS remained level at $24.7 mil ion in
nominal dollars from FY2016 through FY2021 (i.e., funding decreased when accounting for
inflation). Accordingly, USGS funding has not met the SECURE Water Act of 2009 mandate for
an entirely federally funded suite of no fewer than 4,700 streamgage sites. In FY2020, 35% of
FPSs were funded solely by USGS FPS program funds.84 The USGS relies on other federal
agencies or nonfederal partners to fund the rest of the FPSs: in FY2020, 25% of gages were
funded by a combination of FPS and non-FPS funds and 40% were funded entirely by non-FPS
funds. Specific funding sources for the operation of FPS gages include FPS appropriated funds
(about 42%), CMF funds (about 9%), federal agencies other than the USGS (about 23%), and
nonfederal partners (about 26%).
USGS funding for CMF has remained relatively level, ranging from $28.0 mil ion to $31.3
mil ion (in 2019 dollars) over 15 years (Figure 8).85 For the entire USGS Streamgaging Network,

81 Nonfederal partners have provided 50%-57% of funding for the USGS Streamgaging Network over the period of
FY2012 to FY2020. Personal correspondence between CRS and Chad Wagner of the Groundwat er and Streamflow
Information Program, USGS, November 30, 2020.
82 Personal correspondence between CRS and Chad Wagner of the Groundwater and Streamflow Information Program,
USGS, November 30, 2020.
83 Ibid.
84 Ibid.
85 Ibid.
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