PUBLICATIONS -- Transmittal of the report "Summary of the nationwide analysis of the cost effectiveness of the U.S. Geological Survey stream-gaging program (1983-88)" by W. O. Thomas, Jr. and K. L. Wahl
In Reply Refer To: October 18, 1994
Mail Stop 415
OFFICE OF SURFACE WATER TECHNICAL MEMORANDUM NO. 94.08
Subject: PUBLICATIONS -- Transmittal of the report "Summary of
the nationwide analysis of the cost effectiveness of the
U.S. Geological Survey stream-gaging program (1983-88)"
by W. O. Thomas, Jr. and K. L. Wahl
The subject report summarizes a nationwide analysis of the cost
effectiveness of the stream-gaging program that was operated by
the U.S. Geological Survey (USGS) during 1983-88. The subject
report should be of interest to those individuals who operate and
manage the USGS stream-gaging program.
The objective of the nationwide study was to define and document
the most cost-effective methods of furnishing streamflow
information. The study involved three phases: (1) an analysis of
the data uses and availability and documentation of the sources of
funding for each streamflow station; (2) an evaluation of the
utility of using less costly alternative methods, such as
hydrologic flow routing models and statistical methods, to provide
the needed streamflow information; and (3) an analysis of the
cost-effective operation of the stream-gaging program that relates
the accuracy of the streamflow records to various operating
budgets. A prototype study for the nationwide analysis was
described by Fontaine and others (1984). Statewide analyses were
performed by hydrologists in District offices throughout the Water
Resources Division (WRD). The reports describing the analyses for
the individual States are summarized and referenced in the subject
report.
The nationwide analysis documented that (1) multiple uses were
being made of data collected at stations in the USGS stream-gaging
program, (2) simulated flows from hydrologic flow routing models
and statistical methods were not generally of sufficient accuracy
for most uses, and (3) the stream-gaging program was being
operated in an efficient and cost-effective manner. The cost-
effectiveness techniques developed in this study provide an
objective way to compare the relative accuracy of streamflow
records at several locations as a function of the number of visits
to the station.
The USGS has a long history of analyzing and evaluating the
stream-gaging program. The subject report describes the third
nationwide analysis of the USGS stream-gaging program. A brief
history of surface-water network analysis within USGS follows.
The first known nationwide review of the stream-gaging program was
conducted in 1953-58. The purpose of the review was to design a
hydrologic network of stream-gaging stations in accordance with
principles described by Langbein (1954). During this review,
stations were classified as either water management or hydrologic
network (regional hydrology). Within the hydrologic network, the
concept of primary and secondary stations was developed. The
primary stations were for obtaining a long-term sampling of
streamflow and the secondary stations, operated for 5-10 years,
were for obtaining geographic coverage of streamflow
characteristics. Estimation of long-term statistics at the
secondary stations was based on correlation of monthly flows with
the long-term primary stations. Recommendations for improving the
stream-gaging program are summarized in a June 1958 Administration
Report entitled "Progress Report to Chief, Surface Water Branch on
the Nationwide Review of Stream-Gaging Program".
The second national study of the streamflow data-collection
program was conducted in 1969-70. The general procedures for
evaluating the available data, codifying the purposes of stream
gaging and determining the desirable program of the future were
described by Carter and Benson (1969). The stations were
classified by data uses as current use (water management),
planning and design (regional hydrology), long-term trends and
stream environment. Within planning and design, unregulated minor
and principal streams (over 500 square miles) were identified.
The goals of the study were to obtain 25 years of record at
stations on principal streams and obtain 25 years of equivalent
record at points intermediate to gaging stations. The goal for
minor streams was to obtain 10 years of equivalent record through
the use of regression equations that related a variety of
streamflow characteristics to watershed and climatic character-
istics. The regression equations developed in this study and the
results of the program analysis are described in a series of
statewide reports entitled "A Proposed Streamflow Program for
[State Name]." A summary of the nationwide study, including
recommendations for improving the program, is provided by Benson
and Carter (1973).
As an outgrowth of the 1969-70 nationwide analysis, a new network
analysis technique, regression analysis simulation, was developed
by Moss and Karlinger (1974). Ordinary least squares regression
equations, relating streamflow characteristics to watershed and
climatic characteristics, were used to evaluate the time-sampling
and spatial-sampling errors in order to design a more optimal
regional-hydrology network. These techniques, known as Network
Analysis for Regional Information (NARI), are described by Moss
and others (1982). The NARI techniques were used to determine a
more appropriate stream-gaging strategy for reducing the standard
error of the regional regression equations. This strategy may
involve operating the existing stations longer, adding new
stations to the network or some combination of both. The results
of applying these techniques are described in several statewide
reports.
The nationwide cost effectiveness analysis described in the
subject report was conducted during the mid-1980's (Thomas and
Wahl, 1993). The recent emphasis on surface-water network
analysis within the WRD is the use of Generalized Least Squares
(GLS) regression analysis to analyze the regional-hydrology
network. The GLS procedures build on the techniques described by
Moss and others (1982) by utilizing GLS regression procedures that
incorporate the time-sampling error in streamflow characteristics
and an improved measure of the correlation in streamflow
characteristics between stations. The objective is the same as in
NARI and that is to determine if the existing stations should be
operated longer, whether new stations should be installed or some
combination of both. More details on applying these procedures
are given in Office of Surface Water Technical Memorandum
No. 87.08. The technical aspects of the GLS procedures are
described by Tasker and Stedinger (1989) and an example of
applying these techniques to a surface-water data network in
Kansas is described by Medina (1987).
Network analysis techniques have evolved over the years from
(1) correlation of monthly mean flows as recommended by Langbein
(1954), to (2) the use of regional regression equations to
determine the equivalent years of record of estimated streamflow
characteristics at ungaged sites, to (3) the use of regional
regression equations to evaluate the trade-off between time-
sampling and spatial-sampling errors in the design of a regional
hydrology network. Network analyses and program evaluation will
continue to play a prominent role in the management of the USGS
stream-gaging program. Future directions will likely involve the
development of techniques for a more coordinated analysis of
water-quality, ground-water and streamflow networks.
References
Benson, M. A. and Carter, R. W., 1973, A national study of the
streamflow data-collection program: U.S. Geological Survey
Water-Supply Paper 2028, 44 p.
Carter, R. W. and Benson, M. A., 1969, Concepts for the design of
stream-flow data programs: U.S. Geological Survey open-file
report, 20 p.
Fontaine, R. A., Moss, M. E., Smath, J. A., and Thomas, W. O.,
Jr., 1984, Cost effectiveness of the stream-gaging program in
Maine - A prototype for nationwide implementation: U.S.
Geological Survey Water-Supply 2244, 39 p.
Langbein, W. B., 1954, Stream gaging networks: International
Association of Hydrological Sciences (IAHS) Publication No.
38, pp. 293-303.
Medina, K. D., 1987, Analysis of surface-water data network in
Kansas for effectiveness in providing regional streamflow
information [with a section on Theory and Application of
Generalized Least Squares by G. D. Tasker]: U.S. Geological
Survey Water-Supply Paper 2303, 28 p.
Moss, M. E. and Karlinger, M. R., 1974, Surface water network
design by regression analysis simulation: Water Resources
Research, vol. 10, no. 3., pp. 427-433.
Moss, M. E., Gilroy, E. J., Tasker, G. D., and Karlinger, M. R.,
1982, Design of surface-water data networks for regional
information: U.S. Geological Survey Water-Supply Paper 2178,
33 p.
Tasker, G. D. and Stedinger, J. R., 1989, An operational GLS model
for hydrologic regression: Journal of Hydrology, 111, pp.
361-375.
Thomas, W. O., Jr., and Wahl, K. L., 1993, summary of the
nationwide analysis of the cost effectiveness of the
U.S. Geological Survey stream-gaging program (1983-88):
U.S. Geological Survey Water-Resources Investigations
Report 93-4168, 27 p.
Ernest F. Hubbard
Acting Chief
Office of Surface Water
Attachment
WRD DISTRIBUTION: FO