Streamflow Information for the Next Century

A Plan for the National Streamflow Information Program

of the

U.S. Geological Survey

 Open-File Report 99–456

U.S GEOLOGICAL SURVEY

A Proposed Plan

 To increase the level of streamflow information for National needs;

 To improve the way streamgaging stations are funded and located;

 Of new ways to collect, store, and distribute streamflow information.
Streamflow Information for the Next

Century—A Plan for the National

Streamflow Information Program of

the U.S. Geological Survey

U.S. Geological Survey Open-File Report 99–456

A Proposed Plan

• To increase the level of streamflow information for Nation

needs;

• To improve the way streamgaging stations are funded and

located;

• Of new ways to collect, store, and distribute streamflow

information.
U.S. DEPARTMENT OF THE INTERIOR

Bruce Babbitt, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

Copies of this report available upon request from:

U.S. Geological Survey

Information Services

Box 25286

Federal Center

Denver CO 80225

For additional information about this report contact:

Chief, Office of Surface Water

U.S. Geological Survey

12201 Sunrise Valley Drive

Mail Stop 415

Reston VA 20192
CONT

CONTENTS

Introduction................................................................................................................................................................

A Proposed National Streamflow Information Program............................................................................................

Federal-Interest Streamflow Network..............................................................................................................

Other Federal Streamflow Interests .................................................................................................................

New Funding Mechanism................................................................................................................................

A New Mode of Operation ..............................................................................................................................

Protecting Stations from Floods ......................................................................................................................

Intensive Data-Collection during Floods and Droughts ..................................................................................

National Streamflow Assessments...................................................................................................................

Enhanced Streamflow Information Delivery and Products..............................................................................

Data Processing and Dissemination System....................................................................................................

New Technologies............................................................................................................................................

Summary....................................................................................................................................................................

References..................................................................................................................................................................

FIGURES

1-5. Graphs showing:

1. Funding sources for USGS streamgaging stations for fiscal years 1974-99..........................................

2. Annual loss of streamgaging stations with more than 30 years of record .............................................

3. Flux of herbicides in runoff from the Flint River, Georgia from Tropical Storm Alberto, July 1994 ...

4. Long-term changes in streamflow of the Sugar River in Wisconsin......................................................

5. Variation in estimates of the 100-year flood for two different time periods for the Chehalis River nea

 Grand Mound, Washington....................................................................................................................

6. Map showing real-time flow conditions for gaging stations with 30 years of record or more .......................

7. Diagram showing USGS streamgaging station of the future..........................................................................

TABLE

1. Base Federal-interest streamgaging goals, with levels of attainment in 1996 and number of

additional streamgaging stations required to meet goals.............................................................................

Introd

INTRODUCTION

Since 1889, the U.S. Geological Survey (USGS)

has operated a multipurpose streamgaging network

supported primarily by other Federal, State, and local

agencies. Streamgaging stations are the monitoring

tools used to track the flux of water and associated

components in streams and rivers across the Nation.

Streamflow data from them are used for planning and

decisions related to agriculture, industry, urban water

supplies, navigation, riverine and riparian habitat, and

flood hazard identification. The principles that have

guided this national network are:

• Many partners contribute funding for the operation

of gaging stations to collaboratively achieve

Federal mission goals and the individual goals of

the funding agencies.

• All data are freely available to all partners and the

public.

• USGS operates the network on behalf of all partners to achieve economy and standardization of

availability and quality of data.

These goals remain appropriate and applicable

today. However, the multipurpose streamgaging

network needs increased resources and reorientation

because of deficiencies in the present network to meet

Federal goals, changing instrumentation and communication technology, and new opportunities to integrate our streamflow data with information from other

Federal agencies.

“Streamflow data collected by the USGS for

over 100 years and the modern water science

and technology carried out by the WRD form

the cornerstone for national, regional, and

local efforts to cope with hydrologic hazards by

providing continued, up-to-date information

about water conditions and understanding of

hydrologic phenomena.” (From Preface,

Hydrologic Hazards Science at the U.S. 

logical Survey, National Research Coun

1999, p. viii).

In response to a recent Congressional 

the USGS completed an evaluation of the abi

streamgaging network to meet Federal need

streamflow information (U.S. Geological Su

1998). The report found that the degree of at

of the Federal needs rose steadily through th

and 1970s and then leveled off or declined. S

goals are now less well supported than in the 

and 1960s. During the 1990s, the number of 

significantly decreased. Funding from the U

become a smaller and smaller component of 

collaborative network; the shrinking proport

USGS funding for the network continues to r

ability of the network to meet Federal intere

Streamflow Information for the Next Century—

A Plan for the National Streamflow Information Program

of the U.S. Geological Survey

197419751976197719781979198019811982198319841985198619871988198919901991199219931994199

0

10

20

30

40

50

60

70

80

90

100 Other Federal Agencies

State/Local

USGS Matching

Federal Program

Years

Millions

Long-Term Funding Sources

Figure 1. Funding sources for USGS streamgag

for fiscal years 1974-99.
2 Streamflow Information for the Next Century— A Plan for the National Streamflow Information Program of the U.S. Geolog

The present approach to providing streamflow

information is rapidly becoming inadequate and

unstable. The reasons relate to two fundamental

changes that affect the network. The first change is

that USGS funds have become a smaller share of the

total network funding, dropping from 43 to 33 percent,

respectively, between fiscal years 1974 and 1999. This

has caused the network to be more vulnerable as

funding partners consider their own specific needs. In

some cases, they have decided to do without the information or undertake alternative approaches that

provide more limited information. For example, they

may decide to measure flows for only part of the year,

or focus on low flows or high flows, or only provide

stage data and not discharge. Costs can be lowered

when they choose to not provide a capability for

public data access, or to limit access to either real-time

or historical data. Costs can also be reduced by not

including quality assurance or by making fewer visits

to inspect instruments and make discharge measurements. These kinds of cost-cutting measures may be

rational for the current needs of a partner agency.

However, from a national interest perspective they are

sub-optimal, because what is lost is a public good that

has wide applicability for many uses. The loss of 22

percent of the streamgaging stations that record flow

on small, free-flowing rivers since 1971 is one

example of the impact of the funding changes. This

loss of streamflow information is compounded

because often the discontinued streamgaging stations

have long historical records, which are essential for

effective assessment and planning of water-resources

programs by Federal, State, and local governments

(fig. 2).

The second change is that the network now has

a broader set of uses, but specific partners willing to

support these new uses have not emerged. Some of the

new uses arise from changes in society’s interests.

These include the need for flow data to support: waterquality management, aquatic-habitat improvements,

enhanced operations at dams, water-based recreation,

and a public and scientific interest in long-term env

ronmental change. Beneficiaries for these uses are

often diffuse, and thus the services are under- provi

because no one is prepared to step forward to pay f

them. This is what economists call the “free rider

problem,” a well-known issue in terms of provision 

government services.

New uses also arise from advances in technology. In particular, satellite telemetry in conjunct

with the use of the World Wide Web (WWW) has

greatly enhanced the value of the data and also the

demand and expectations about its availability and

reliability. The Internet can now be used to provide

current data on floods and recreational flow conditions. However, these technologies have significant

infrastructure costs and demand a level of reliability 

service that was never before required of the USGS

To make the present partners bear these costs alone

given that the benefits of the technologies are wide

spread, is unfair and unrealistic.

In addition to funding and infrastructure issu

other components of the network require reassessment. These include documenting floods and droug

The number of gaging stations has declined for a decade, more and more costs

are borne by non-Federal partners, and the loss of stations with long-term

records is accelerating.

0

20

40

60

80

100

120

140

160

180

1921 1931 1941 1951 1961 1971 1981 

Number of Streamgaging Stations

Year

Figure 2. Annual loss of streamgaging stations with mo

than 30 years of record.
A PROPOSED NATIONAL STREAMFLOW INFORMATION PRO

assessing streamflow trends, and developing systems

for improving the monitoring and dissemination of

streamflow data and related information. Current

opportunities to document the characteristics and

distributions of floods and droughts are limited to

those events when supplemental funds are appropriated after a Presidential Declaration of a Disaster.

USGS should have base funds for post-event data

collection to provide valuable information for characterizing the events and to help mitigate the effects of

future events. Likewise, there is a need for ongoing

assessments of streamflow data at the national and

regional level so that water-resource managers, planners, engineers, forecasters, and emergency management officials have the most current statistical

information on floods and droughts. The expanding

demand for real-time streamflow data and timely

assessments of streamflow characteristics and trends

requires that new capabilities be developed both for

monitoring of conditions at field sites and for disseminating reliable and accurate data and results of assessments to many thousands of users nationwide. The

approaches described in this report attempt to respond

to the changing circumstances of the streamgaging

infrastructure in a way that serves both the specific

needs of partners and the broader national interest for

streamflow information.

A PROPOSED NATIONAL STREAMFLOW

INFORMATION PROGRAM

A USGS Committee reexamined its streamgaging program, evaluating not only the streamgaging

stations but the full suite of products derived from the

network. The Committee recommended initiating the

National Streamflow Information Program (NSIP).

The NSIP will produce information for multiple uses,

be shared freely, made readily accessible for current

use, archived for future use, be quality assured, and be

viewed as neutral, objective, and of high quality by all

parties. NSIP will consist of the following c

nents:

1. A nationwide system of Federal-interest s

gaging stations for measuring streamflo

related environmental variables (precip

temperature) reliably and continuously 

2. A program for intensive data collection in 

to major floods and droughts;

3. A program for periodic assessments and i

tion of streamflow data to better define 

tical characteristics and trends;

4. A system for real-time streamflow inform

delivery to customers that includes data

processing, quality assurance, archival, 

access;

5. A program of techniques development and 

Many of the features of NSIP are cons

with recent recommendations of the Nationa

Research Council (1992, 1999). Providing ti

able information that can be used for many d

by many parties is the goal of NSIP. The pur

this report is to define NSIP and give the mot

its conceptual design and seek input from th

funding partners and users of streamflow inf

This process will lead to detailed funding an

mentation plans for the NSIP.

Federal-Interest Streamflow Netwo

Federal streamflow information needs 

that should be met by the USGS streamgagin

network even in the absence of support from 

partners. These include:

Compacts and Decrees for Interstate and

International Transfers (350 locations).

Interstate compacts, court decrees, and intern

treaties mandate streamgaging by the USGS 

line-crossings and other points of flow adjud

Federal streamflow information needs are those that should be met by the U

streamgaging network even in the absence of support from funding partn
4 Streamflow Information for the Next Century— A Plan for the National Streamflow Information Program of the U.S. Geolog

National Weather Service (NWS) Flood Forecasts

(2,950 locations served).

Real-time discharge and stage data are required in

support of NWS river forecasts and flood warnings at

service locations across the country.

Water Budgets (329 accounting units monitored).

Tracking and quantifying the volumes and flow rates

of water from upland watersheds to major rivers as it

moves through the drainage systems of the Nation to

assist in national water assessments, planning studies,

and policy decisions.

Regionalization and Long-term Trends

(800 stations).

Regionalization is the process of using a representative

flow record as a surrogate for other locations where

streamgaging stations do not exist. It is the backbone

of USGS methods for estimating streamflow characteristics at ungaged locations. To reduce errors in

existing regional relations, and to estimate changes in

flow characteristics that result from environmental

changes, at least one streamgaging station is required

for every unique ecoregion and water-budget

accounting-unit combination in the Nation.

Water Quality (850 stations)

The water-quality goal has been modified slightly

from the Report to Congress to include two components. The first component is a minimal Federal

network of streamgaging stations that are needed to

support three national water-quality networks opera

by the USGS. These networks are the National Stre

Quality Accounting Network (NASQAN), a set of 

stations that cover the Nation’s largest rivers; the

National Water Quality Assessment (NAWQA) low

intensity network, a set of 62 stations that cover int

mediate-sized rivers; and Benchmark, a set of 48 sm

pristine watersheds. The second component includ

locations where streamflow information is needed 

planning and implementing restoration efforts to

improve water quality in those watersheds that are

known to have degraded water quality. It is anticipa

this list will change over time as new information i

obtained, but that there will be a continual need for

streamflow information in support of water-quality

improvement activities in about 700 watersheds

nationwide.

The list of Federal needs presented here and 

table 1 represents our view of the most important

needs from a Federal perspective. Review and

comment on this definition of core needs will be

sought from many stakeholders and from the Natio

Research Council. Reactions to this definition of co

needs must be made with the recognition that it rep

sents a "floor" and not a "ceiling" for the needs tha

should be addressed by a Federal streamgaging

network.

Table 1. Base Federal-interest streamgaging goals, with levels of attainment

in 1996 and number of additional streamgaging stations required to meet goals

Base Federal Interest

Number of

sites or

reaches to

be served

Level of

attainment of

goal in

1996, in

percent

Number of

additional

streamgaging

stations

needed to

meet goal

Compacts and Decrees 350 56 150

NWS Flood-Forecast Sites 2950 73 800

Water Budgets 350 77 100

Long-term Changes 800 76 200

Water Quality 700 88 100

TOTAL 1,350
A PROPOSED NATIONAL STREAMFLOW INFORMATION PRO

To meet the streamgaging needs defined by the

list of Federal interests we propose to:

• Evaluate the current USGS streamgaging network

for meeting defined Federal needs; identify locations that require additional streamgaging

stations.

• Evaluate streamgaging stations operated by Federal

partners and cooperators that are properly located

to fill one or more Federal needs; evaluate what

modifications in equipment or operation are

needed to meet Federal streamgaging station

goals; provide support for necessary upgrades.

• Consider reactivated or new stations to fulfill the

remainder of the Federal needs.

Other Federal Streamflow Interests

It must be emphasized that the Federal interests

discussed above are a base level and do not represent

the full range of Federal streamflow information

needs. Other important Federal interests are:

• Information for sites needing flood forecasts that

are not presently served by NWS.

• Federal Emergency Management Agency (FEMA)

requirements for flood-insurance-rate maps.

• Streamflow information to support effective stewardship of Federal lands.

• Widespread monitoring in support of water-quality

standards, waste-water discharge allocations,

restoration efforts, and recovery plans for threatened or endangered aquatic species.

• Data for national water-use assessments.

• Data to support operation and management of

major Federal reservoirs.

• Real-time monitoring of flow in Wild and Scenic

Rivers.

New Funding Mechanism

The report of the Review of the Federal-State

Cooperative Water Program (in press) recommended

that the USGS:

“Establish an adequate and perman

streamflow monitoring network in the N

interest. Funding for long-term data col

should be stressed as a national priority. 

Task Force supports the concept that the 

government should provide 100% fundin

national stream-gaging network, and tha

funding for this network should not com

expense of the Cooperative Water Progra

Emery Cleaves, the Maryland State G

speaking for the Association of American St

gists, offered this statement in an article in G

on stream gaging:

“The federal government should fun

entire cost of a base-line, national netwo

stream gages that measures the ‘pulse’ o

nation’s surface-water resources.”

Uncertainties in funding from year to 

led to a fragmented network of streamgagin

that come and go, and thus have shorter peri

record on which to make estimates of future 

conditions or monitor streamflow trends. So

the search for funding partners is unsuccess

critical national interests go unmet, as was t

along the Liking River, Kentucky:

On 1 March 1997, northern Kentuck

drenched with up to 25 centimeters of ra

Licking River, which meanders through 

town of Falmouth, rose a meter in only 3 

and kept on rising. By evening, Falmout

emergency siren was wailing and police 

shouting evacuation orders through bul

Most of the 2400 residents managed to fl

the water came so fast, even shoving hou

their foundations, that some had to be re

from rooftops. Four people in mobile ho

drowned. The river had crested 4 meters 

and 6 hours earlier than the National W

Service (NWS) had predicted. NWS offic

admitted that they had underestimated th

ger, but added that their forecasts had be

severely hampered by the loss of a crucia

ing station 32 kilometers upriver, which 

in a budget crisis in 1994. "It was like a 

Streamgaging stations that satisfy the defined Federal interests should be fu

entirely by Federal appropriation.
6 Streamflow Information for the Next Century— A Plan for the National Streamflow Information Program of the U.S. Geolog

flood," says Mark Callahan of the NWS's Louisville office. "Without that gage, we were

blind." (Science, Aug. 23, 1999)

One of the weaknesses of the current network is

the funding mechanism. Funding partners are required

to pay an amount that represents the total cost of the

network divided by the number of gages. This amount

encompasses a share of the fixed costs that are associated with the very existence of the network and the

marginal cost of operating a streamgaging station in

the network. Fixed costs include the data-management

and dissemination system, technology development

and testing, quality assurance, and network management. Current (1999) estimates are that about

40 percent of the average cost of operating a station

are fixed costs or about $37 million per year for the

current network. Under NSIP the fixed costs of the

network would be covered through federal appropriations. The marginal costs of operating a streamgaging

station include personnel costs associated with

inspecting the station, making discharge measurements, and computing and publishing the data; the

amortized cost of the instruments and communication

equipment; the cost of periodic maintenance and

repairs; and the travel expenses for the site visits.

Under the NSIP concept, the total cost of tho

streamgaging stations needed to meet the base Fede

needs would be covered by Federal appropriations.

For totally new stations, these would include a first

year installation cost of $20,000 to $50,000 per

station. The cost would be lower for reactivating

former USGS stations or for upgrading stations ope

ated by others. However, there are significant additional costs that may be required for many existing

stations to meet the requirements of a base Federal

network station. The marginal costs of station oper

tions, to be funded by the Federal appropriations fo

the base Federal network, are expected to average

about $6,000 per year.

Other streamgaging stations in NSIP would s

require funding from partners. The Federal-State

Cooperative Water Program would continue to be a

major mechanism for funding those stations that m

identified Federal needs but are not a part of the ba

Federal network. The annual marginal costs of ope

tion would be shared by the USGS and its partners

with no more than 50 percent of the marginal costs

paid from USGS appropriations. Streamgaging

stations needed to meet the needs of other Federal

agencies would have their marginal costs fully fund

by the requesting agency. The USGS however, wou

continue to work collectively with many agencies t

build coalitions of funding partners to share the cos

of stations that serve many needs. At such time as t

NSIP plans may become accepted and implementat

begins, detailed cost estimation and transition plan

ning will be done. The proposed shift in the fundin

paradigm is a significant one, and reactions of fund

partners will need to be considered carefully. Over

time, the proposed funding mechanism would lead 

more stability, not only in the base Federal part of t

network but also in the cooperatively funded part a

well.

Flooding in Grand Forks, North Dakota,

during the 1997 flood.

The fixed costs of the USGS stream gaging program should be funded

by Federal appropriation.
A PROPOSED NATIONAL STREAMFLOW INFORMATION PRO

A New Mode of Operation

Presently, about two-thirds of USGS-operated

streamgaging stations have real-time telemetry capability. Under NSIP, where telemetry is appropriate and

possible, USGS gaging stations should be equipped to

enable real-time data. Where appropriate, waterquality data, such as temperature and specific conductance would be collected at streamgaging stations on a

continuous basis. Other water-quality measures would

be collected as funding opportunities and needs arise.

A full-service Federal-interest streamflow and waterquality station could eventually include continuous

information on stage and discharge, and a suite of

water-quality parameters, such as temperature, specific

conductance (a measure of salinity), pH, dissolved

oxygen, suspended sediment, bacteria, metals, and

organic constituents. A nationwide network of streamgaging stations that collects important selected waterquality data would provide a valuable source of information for monitoring habitat, tracking sources of

contamination, computing loads of contaminants

during floods, viewing water-quality-conditions at a

regional scale, and planning the restoration of

degraded streams, rivers, and lakes.

Protecting Stations from Floods

Many streamgaging stations are at risk during

times of flood. The location and physical condition of

these stations cause them to be damaged or inundated

during major floods. Thus, important information may

not available to forecasters and emergency managers

when it is needed most. Under NSIP, critical USGS

streamgaging stations would be hardened to withstand

flows up to the 200-year flood level. All crit

stations would have a stream-to-WWW data

reliability of 99 percent. A program of strea

station hardening will significantly decrease 

for the USGS to seek supplemental appropri

station repairs when catastrophic floods occu

Intensive Data-Collection during F

and Droughts

Floods and droughts are extreme even

hydrologic surface-water flow system. As su

define the points of concern of natural and co

surface-water systems, such as water supply

capacity, water quality, and habitat. The sum

drought in the eastern United States in 1999 

lighted how vulnerable the Nation is to wate

ages.

The NSIP approach to data collection 

and droughts will be to supplement data from 

gaging stations with systematic field survey

flood and drought is unique, but a standardiz

approach to field work and data collection w

that the important aspects of each event are 

mented. Data collected during these events w

include information about precipitation dura

tion/frequency, river stage and discharge, an

nistic sampling of water-quality variables to 

suspended sediment, nutrients, specific cond

alkalinity, bacteria, pesticides, and hydrocar

Changes in geomorphology of river channel

river-bank erosion location and processes, a

mentation volumes and distribution would b

mented for high- as well as low-flow conditi

The marginal costs for non-Federal base need streamgaging stations wou

funded by partners.

Critical USGS gaging stations would be hardened to withstand flows up t

200-year flood.
8 Streamflow Information for the Next Century— A Plan for the National Streamflow Information Program of the U.S. Geolog

For example, figure 3 shows the changing

concentrations of herbicides in runoff from the Flin

River at Newton, Georgia, from Tropical Storm

Alberto in July 1994. These data show that highest

concentrations occurred 4 to 6 days prior to the pea

discharge on this river. Such data are valuable to tra

loads of contaminants, the timing of their transport,

and to monitor the impact on downstream ecosystem

Such data should be available for many gaging statio

across the country for many purposes, including

knowing when toxic plumes have passed water-supp

intakes and when to reopen water recreational sites

Important information from floods and droughts will be documented.

Flooded USGS streamgaging station on the

Falling River near Juliette, Georgia.

Drought conditions

Flood conditions
A PROPOSED NATIONAL STREAMFLOW INFORMATION PRO

National Streamflow Assessments

The value of streamflow data from individual

streamgaging stations is multiplied when the records

are subjected to systematic analysis and interpretation.

Streamflow records from any gaged site contain information not only on the actual history of streamflow

during the period of record, but also on the statistical

properties (means, flood recurrence intervals, low-flow

characteristics, and so forth) of the streamflow

process. The similarity of hydrologic response across

basins allows information from gaged basin

used in estimation of the streamflow charact

ungaged basins by means of regionalization 

others, 1995). Because the number of small, 

stream basins will always far exceed the num

gaged basins, regionalization is a crucial com

the overall USGS program of streamflow in

processing. Current (1999) methods of regio

typically estimate streamflow characteristics 

ungaged basins with a standard error in the r

to 70 percent.

The institution of a program of data in

tion would reveal regional and national patte

streamflow characteristics and their tempora

Human modifications to runoff characteristi

likely to be reflected in streamflow data incl

voir construction, dam removal, changing la

ground-water pumpage, water consumption

alterations, and interbasin transfers. For exa

southeastern Wisconsin, long-term flow data 

Sugar River gaging station near Brodhead, s

annual flood peaks have decreased by 30 pe

annual 7-day low flows increased by 25 perc

in response to improved agricultural land pr

(fig. 4)

CONCENTRATION, IN

MICROGRAMS PER LITER

DISCHARGE, IN THOUSANDS

OF CUBIC FEET PER SECOND

0.15

0.10

0.05

0

110

100

90

80

70

60

50

40

30

20

10

0 5 10 15

July 1994

20 25 30

Discharge

Cyanazine

Atrazine

Figure 3. Flux of herbicides in runoff from the Flint River,

Georgia from Tropical Storm Alberto, July 1994.

Streamflow information would be interpreted on national and regional sca

0

20,000

5,000

10,000

15,000

ANNUAL PEAK DISCHARGE 

INCUBIC FEET PER SECOND

TREND

DISCHARGE

ANNUAL FLOOD PEAKS ANNUAL 7-DAY LOW FLOWS

05436500 SUGAR RIVER NEAR BRODHEAD, WISCONSIN (DRIFTLESS AREA WATERSHED)

Figure 4. Long-term changes in streamflow of the Sugar River in Wisconsin (from Gebert and Krug, 1996)
10 Streamflow Information for the Next Century— A Plan for the National Streamflow Information Program of the U.S. Geolog

194019501960197019801990

YEAR

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

DISCHARGE IN CUBIC FEET PER SECOND

ANNUAL PEAK DISCHARGE

1976 ESTIMATE OF THE 100-YEAR FLOOD

(used in FEMA Flood Insurance Study)

1996 ESTIMATE OF THE 100-YEAR FLOOD

The program will address such questions as

“Has flooding increased in the Nation in recent years?

What are the impacts of El Nino Southern Oscillation

(ENSO) on the national water supply? Can we see the

effects of greenhouse warming in the national streamflow record?” The value of information from longterm streamgaging stations for these types of analyses

are demonstrated in figure 5. An estimate of the

100-year flood for the Chehalis River in Washington

was determined in 1976 using over 40 years of streamflow record. This estimate of about 55,000 cubic feet

per second was used for a FEMA Flood Insurance

Study. In 1996, the 100-year flood for the Chehalis

River was again estimated but with an additional

20 years of streamflow record to use in the calculation.

The 1996 estimate of the 100-year flood was about

72,000 cubic feet per second, an increase of 31 percent

over the 1976 estimate.

Enhanced Streamflow Information

Delivery and Products

The USGS customer base has expanded rapidly

as a result of WWW dissemination of near real-time

streamflow information. The introduction of an efficient information delivery mechanism has significantly grown and diversified the market for USGS

streamflow products. Further development of the

WWW user interface(s) to near real-time and historical streamflow data would improve service to current

customers and increase the customer base. WWW

access to other information products (for example,

streamflow characteristics) could be expected to ha

a similar effect. Accordingly, NSIP will provide

convenient, reliable access to all of its information

products through the WWW.

“In my work, whether as a real estate broker in the Berkshire Hills of western Massachu

setts, as a Conservation Commissioner for my

town of Stockbridge, or as a local watershed

project coordinator for the Housatonic Valley

Association, USGS map products and on-line

web sites provide exceptional value for my tax

dollar because they empower all of us to do far

better work than we could do on our own.

That’s what I have always thought government

was supposed to do, and you-all have hit the

mark dead center.” (Shepley W. Evans, Stockbridge, Massachusetts)

The current convention of providing routine

access only to daily streamflow values does not me

the needs of many customers. Data at finer time sca

are critical to water-quality analyses, habitat studie

and planning for flood control and water regulation

The existing focus on daily streamflow values is an

artifact of the era when paper reports were the prim

means of data dissemination. Under NSIP, all availa

stage and streamflow data will typically be dissemi

nated at the time resolution of actual measurement

(usually 15, 30, or 60 minutes) and as user-request

time averages (daily, monthly, and annual) through 

interface that unifies historical and real-time data

bases.

The USGS will develop partnerships for info

mation delivery with other agencies. For example,

NWS streamflow forecasts and USGS streamflow

measurements are similar types of time-series data

Where USGS gage sites and NWS forecast service

locations coincide, the USGS will provide unified

graphical presentations of NWS forecasts in the

context of USGS measurements and streamflow ch

acteristics.

Recently, the USGS began serving maps wit

national coverage of flow conditions at real-time

streamgaging stations (figure 6). The map depicts

color-coded USGS gaging stations whose color rep

sents discharge as a percentile, which is computed

from the period of record for the current day of the

year. Only stations having at least 30 years of recor

Figure 5. Variation in estimates of the 100-year flood for

two different time periods for the Chehalis River near Grand

Mound, Washington.
A PROPOSED NATIONAL STREAMFLOW INFORMATION PRO

are used. This provides a real-time, small-scale view

of the Nation’s surface-water circulatory system.

Figure 6 shows such a display that reflects the height

of the drought in the Northeast in the summer 1999.

“Streamflow gaging stations are diminishing in number at a time when most other

sources of other types of hydrologic data are

increasing. With the ever-present importance of

the calibration and verification of hydrologic

models, and the increasing availability of rainfall estimates from the NEXRAD system, the

decline in stream flow gaging stations is alarming... At present, the USGS funding of the

Cooperative Program is over-matched. That is,

there are more state, local, and tribal dollars

than federal dollars spent on stream gaging.

This lack of balance may result in a furt

nificant reduction in the number of strea

ing stations if state, local, or tribal entiti

reduce their budgets for stream gaging. 

decline in the number of stream flow gag

stations must be halted.” (American Soci

Civil Engineers Task Committee on GIS 

ules and Distributed Models of the Water

Report, 1999, p. 63-64).

The USGS will work with FEMA, NW

other relevant agencies to design an integrat

program that will modernize techniques for 

ation of flood-risk maps, develop a process f

revision of flood maps, provide near real-tim

flood inundation areas, and provide forecast 

flood-inundation areas.

NSIP will provide convenient and reliable access to all of its information prod

through the World Wide Web.

Figure 6. Real-time flow conditions for gaging stations with 30 years of record or more. Color of dots

represent flow conditions: red-orange are low flows, black and blue are high flows.
12 Streamflow Information for the Next Century—A Plan for the National Streamflow Information Program of the U.S. Geological 

Data Processing and Dissemination

System

As part of NSIP, the delivery of more real-time

data and enhanced hydrologic assessment products

will be accomplished by taking advantage of new database design tools and information-delivery technology.

Recent advances in computing, telecommunications,

and WWW-based information access are changing

procedures for processing streamflow data within the

USGS. Most important among these changes is the

public availability of real-time streamflow data from

USGS streamgaging stations. This availability has

created significant new interest in water data and

presented new challenges for real-time streamflow

data processing. A change in data-processing procedures is needed to provide accurate historical and realtime data of known precision within minutes to a

broad customer base.

The data routing, archiving and real-time public

access components will be co-located at several Data

Access Centers. Each Data Access Center will have

the same set of data bases, software, and functionality.

Duplication of data-serving sites creates a reliable

system for providing streamflow information. Several

sites could go "offline" due to power failure or

communication failure, and streamflow information

still could be provided in near real-time over the

WWW. The Data Access Centers are intentionally

located away from the Data Processing Centers, in

order to shield the Data Processing Centers from

Internet traffic at the Data Access Centers. At these

central processing stations, any poor or missing flow

records would be filled in with provisional data generated from flow models that use information from

surrounding gages. All flow information served would

have uncertainty estimates to define data confidence.

New Technologies

The success of the National Streamflow Information Program will depend on new and original tools

and techniques. The most commonly used technique

for streamflow estimation (continuous stage measurement, correlated to periodic cross-sectional surveys 

velocity using velocity meters) has remained virtual

unchanged for a century. For the most part, this is a

tribute to its robustness, accuracy, and cost-effective

ness. Concerns for personal safety, accuracy, reliability, and efficiency, however, provide justification

for ongoing efforts to identify and develop new and

emerging technologies for streamflow measurement

NSIP will pursue research and development on new

and emerging technologies for determining river stag

velocity, and discharge without putting people and

equipment in contact with the water. Ultimately, the

gaging station of the future might operate as shown 

figure 7, where stage, cross-section, and watervelocity are all determined by remote sensing from th

side of the river, without contact with the stream.

Additional new tools and methods that are

required include:

• Development of acoustic doppler current profilers

for use in shallow and low-velocity streams and

on remotely operated vessels.

• Experimental and theoretical research to develop

new, more cost-effective indirect methods of es

mating flood flows, to identify processes associ

ated with these flows, and to develop costeffective means to reconstruct flood peaks that g

ungaged or are too dangerous to measure directl

The utility of multi-dimensional flow models an

high-resolution digital elevation data will be ful

explored in such investigations.

• Improved quality-assurance techniques to screen

data for faulty instruments and to quantify the

uncertainty of streamflow data.

• Reexamination of the theoretical basis for extrapo

lating short-term streamgaging station data to 10

and 500-year events to reflect changing climate

land use, and other unidentified controls. This

will include an analysis of mixed populations o

floods caused by hurricanes, frontal systems, ra

on snow, and El Nino and other climatic pattern

In recent decades, the USGS and others in the

scientific community have developed an array of

powerful computational tools for modeling of water

NSIP will identify and develop new and emerging technologies for streamflow

measurements.
SUM

sheds and stream channels. The USGS will initiate a

set of pilot studies to determine the cost-effectiveness

of and demand for a national program of modelderived streamflow information products. The USGS

also will undertake a program of research into the

physical causes of spatial and temporal variations in

streamflow characteristics in response to climatic variability and changing land-use practices in many watersheds.

SUMMARY

For over 110 years the United States Geological

Survey (USGS), which has no regulatory or developmental responsibilities, has provided unbiased, highquality streamflow data used by many organizations

for many purposes. The USGS operates a collaborative national network of streamgaging stations that

meets many Federal, State, and local user needs

utilizing multiple sources of funding. This network has

evolved over time, but today it is at a crossroads. The

need for both real-time data and historical information

to support flood and drought mitigation efforts, waterquality and habitat restoration, water-supply planning

and other critical needs have stretched the current

(1999) network to and in some cases beyond its capabilities. The streamgaging station network needs to be

modernized, optimized, and reorganized to be able to

answer questions and provide the information needed

by a wide community of water-information users.

This plan, which includes enhancemen

streamgaging infrastructure, a new funding m

nism, supplemental measurements of floods 

droughts, ongoing assessments of streamflow 

teristics and trends, and improved systems fo

toring and disseminating streamflow inform

step in that direction. This report represents 

thoughts of the USGS regarding the future o

flow information for the Nation. We seek inp

all interested parties regarding our vision of 

Comments or questions should be directed t

Office of Surface Water, USGS..

REFERENCES

American Society of Civil Engineers, 1999, Task

Committee on GIS Modules, p 63-64.

Cleaves, E.T., 1998, A call for a Federal streamg

program: Geotimes, October 1998, p. 5.

Committee on U.S. Geological Survey Water Re

Research, 1992, Regional hydrology and th

stream gaging network: National Research 

National Academy Press, Washington, D.C

Committee on Assessing the Costs of Natural Di

1999, The impacts of natural disasters: a fra

for loss estimation: National Research Coun

National Academy Press, Washington, D.C

Committee on U.S. Geological Survey Water Re

Research, 1999, Hydrologic hazards science 

U.S. Geological Survey: National Research 

National Academy Press, Washington, D.C

Gebert, W.A. and Krug, W.R., 1996, Streamflow 

Wisconsin’s Driftless area: Water Resource

v. 32, p. 733-744.

Stokstad, Erik, 1999, HYDROLOGY: Scarcity o

Stream Gages Threatens Forecasts: Science

1999, p. 1199.

U.S. Geological Survey, 1998, A new evaluation 

USGS streamgaging Network: A Report to 

20p.

U.S. Geological Survey, in press, Report of the ta

review the Federal-State Cooperative Water 

August 1999, Circular No. 1192

Wahl, K.L., Thomas, W.O., Jr., and Hirsch, R.M

Stream-gaging program of the U.S. Geologi

U.S. Geological Survey Circular 1123, 22 p

Satellite telemetry

Velocity

Sounding Stage

Flow

direction

Figure 7. USGS streamgaging station of the future.