Water Resources Applications Software
Summary of GLSNET
NAME
glsnet - Regional hydrologic regression and network analysis using
generalized least squares
ABSTRACT
The GLSNET procedure uses an analysis of residuals technique to
estimate a regional regression equation to predict flow
characteristics at ungaged sites. The regression analysis assigns
different weights to observed flow characteristics. These weights
are based on record length, cross correlation with flow
characteristics at other sites, and an assumed model error
structure.
METHOD
Stedinger and Tasker (1985, 1986) documented the usefulness of an
estimated generalized least squares (EGLS) regression procedure for
regional regression of streamflow characteristics. The EGLS
procedure assigns different weights to observed flow characteristics
based on their record length, cross correlation with flow
characteristics at other sites, and the model error variance.
Tasker and Stedinger (1989) provide further details on how the
elements of the weighting matrix are determined.
The problem of identifying the sites from which to collect future
streamflow data is formulated as a mathematical program using
regional information and is subject to budget constraints. An
approximate solution is obtained using a step-backward technique
that identifies gaging station sites, either existing or new, to
discontinue data collection, or not start data collection,
respectively, if the budget is exceeded. The method allows a
network manager to design a nearly optimal streamflow data network
for collecting regional information.
HISTORY
Version 2.6 1998/05/21 - Network analysis changed to run a zero
planning horizon. Corrected a problem in the code that caused
the program to quit if the user tried to have a 6th parameter in
the network analysis regression equation.
Version 2.5 1997/09/29 - Corrected an error in the calculation of
the derivative of the objective function with respect to the
number of years of record.
Version 2.4 1997/05/09 - Changed how the average sampling error
variance is computed in the network analysis. Should be faster.
Simplified procedures for recompiling program with different
dimensions.
Version 2.3 1996/12/17 - Incorrect conversion of degree-minute-
second latitudes and longitudes to decimal degrees (off by a
factor of 10) has been corrected. This would have been a problem
only in the following cases:
1. Latitudes and longitudes were stored in the WDM attributes
LATDMS & LNGDMS. (Note that data entered in the iowdm options
peak, n-day, and (or) basin would not have this problem as
lat/lng were stored as decimal degrees in attributes LATDEG &
LNGDEG.)
2. When proposed stations were being added for the network
analysis.
Version 2.2 1995/10/08 - Increased the maximum number of stations
from 300 to 600.
1995/10/21 - Fixed graphics to correctly handle Modify/Device.
1995/11/14 - Correction made in how peak qualification codes are
being handled.
There was a problem if the user specified no qualification codes
(all peaks were to be included). In this case, peaks that had no
qualification codes may not have been included.
Version 2.1 1994/11/01 - Corrections made in the partial record
option and the ordinary least squares option.
Corrected a bug that caused the program to bomb when the user
entered an invalid name for the input file.
Corrected bugs that caused the ordinary least squares option to
fail.
DATA REQUIREMENTS
At each site in the network of gages a set of basin characteristics,
such as drainage area, basin slope, and mean annual precipitation; a
set of flow characteristics, such as 100-year flood, mean annual
flood, or 7-day 10-year low flow; and a time series of observed
flows, such as annual peaks, or annual 7-day low flows; are required
to be in a WDM file.
OUTPUT OPTIONS
Output is the final regression model and related residual analysis
including influence statistics and various optional graphs. In
addition, for the network analysis a list of stations to continue
given various budget levels is output.
SYSTEM REQUIREMENTS
GLSNET is written in Fortran 77 with the following extension: use of
include files. The ANN, WAIDE, AWSTAT, GRAPH, STATS, AIDE, WDM,
ADWDM, and UTIL libraries from LIB are required to recompile. For
more information, see System Requirements in LIB.
DOCUMENTATION
Tasker, G.D., and Stedinger, J.R., 1989, An operational GLS model
for hydrologic regression: Journal of Hydrology, v. 111, p.
361-375.
REFERENCES
Asquith, W.H., and Slade R.M, Jr., 1997, Regional Equations for
estimation of peak-streamflow frequency for natural basins in
Texas, U.S.Geological Survey Water-Resources Investigation Report
96-4307.
Asquith, W.H., 1998, Peak-flow frequecny for tributaries of the
Colorado River downstream of Austin, Texas, U.S.Geological
Survey Water-Resources Investigation Report 98-4015.
Brabets, T.P., 1996, Evaluation of the Streamflow-gaging network of
Alaska in providing regional streamflow information,
U.S.Geological Survey Water-Resources Investigation Report
96-4001.
Clement, R.W., 1987, Floods in Kansas and techniques for estimating
their magnitude and frequency: U.S. Geological Survey Water-
Resources Investigations Report 87-4008.
Curtis, G.W., 1987, Techniques for estimating flood-peak discharges
and frequencies on rural streams in Illinois: U.S. Geological
Survey Water-Resources Investigations Report 87-4207.
Hodge, S.A, and Tasker, G.D., 1995, Magnitude and frequency of
floods in Arkansas, U.S.Geological Survey Water-Resources
Investigation Report 95-4224.
Landers, M.N., and Wilson, K.V., Jr., 1991, Flood characteristics of
Mississippi streams: U.S. Geological Survey Water-Resources
Investigations Report 91-4037.
Livingston, R.K., and Minges, D.R., 1987, Techniques for estimating
regional flood characteristics of small rural watersheds in the
Plains Region of eastern Colorado: U.S. Geological Survey Water-
Resources Investigations Report 87-4094, 72 p.
Ludwig, A.H., and Tasker, G.D., 1993, Regionalization of low flow
characteristics of Arkansas streams: U.S. Geological Survey
Water-Resources Investigations Report 93-4013, 19 p.
Lui, S., and Stedinger, J.R., 1991, Low flow frequency analysis with
ordinary and tobit regression: Proc. 18th annual conference and
symposium ASCE WRPMD, p. 27-31.
Lumia, R., 1991, Regionalization of flood discharges for rural,
unregulated streams in New York: U.S. Geological Survey Water-
Resources Investigations Report 90-4197.
Medina, K.D., and Tasker, G.D., 1985, Analysis of surface water data
network in Kansas for effectiveness in providing regional
information: U.S. Geological Survey Water-Supply Paper 2203, 27
p.
Roberts, J.W., and Kolton, G.F., 1989, Techniques for estimating
flood-peak discharges of rural, unregulated streams in Ohio:
U.S. Geological Survey Water-Resources Investigations Report
89-4126.
Stedinger, J.R., and Tasker, G.D., 1985, Regional hydrologic
analysis 1: Water Resources Research, v. 21, no. 9, p. 1421-1432.
Stedinger, J.R., and Tasker, G.D., 1986, Regional hydrologic
analysis 2: Water Resources Research, v. 22, no. 10, p.
1487-1499.
Tasker, G.D., 1986, Generating efficient gaging plans for regional
information in Moss, M.E., ed., Integrated Design of Hydrological
Networks: International Association of Hydrological Sciences
publication no. 158, p. 269-281.
Tasker, G.D., 1991, Identifying stream gauges to operate for
regional information: Transportation Research Record 1319, p.
131-136.
Vogel, R.M., and Kroll, C.N., 1990, Generalized low-flow frequency
relationships for ungaged sites in Massachusetts: Water Resources
Bulletin, v. 26, no. 2, p. 241-253.
TRAINING
Statistical Approach to Surface-Water Hydrologic Analysis
(SW2011TC), offered annually at the USGS National Training Center.
CONTACTS
Operation and Distribution:
U.S. Geological Survey
Hydrologic Analysis Software Support Program
437 National Center
Reston, VA 20192
h2osoft@usgs.gov
Official versions of U.S. Geological Survey water-resources analysis
software are available for electronic retrieval via the World Wide
Web (WWW) at:
http://water.usgs.gov/software/
and via anonymous File Transfer Protocol (FTP) from:
water.usgs.gov (path: /pub/software).
The WWW page and anonymous FTP directory from which the GLSNET
software can be retrieved are, respectively:
http://water.usgs.gov/software/glsnet.html
--and--
/pub/software/surface_water/glsnet
SEE ALSO
annie(1) - Program to list, table, plot data in a WDM file
iowdm(1) - Program to store time-series data in a WDM file
peakfq(1) - Flood-frequency analysis based on Bulletin 17B
swstat(1) - Surface-water statistics
wdm(1) - Watershed Data Management system
The URL for this page is: http://water.usgs.gov/cgi-bin/man_wrdapp?glsnet
Send questions or comments to h2osoft@usgs.gov