NSS National Streamflow Statistics Program NSS - Version 6.1, 2016/01/06 TABLE OF CONTENTS A. DESCRIPTION B. DOCUMENTATION C. HARDWARE REQUIREMENTS D. INSTALLATION E. RUNNING NSS F. HELP FILE G. VERSION HISTORY H. DATABASE I. CONTACTS A. DESCRIPTION NSS is a Windows program for estimating the magnitude and probability of peak discharges for unregulated rural and urban watersheds and for estimating other streamflow statistics for unregulated rural watersheds. NSS includes more than 7,000 regression equations for use in estimating streamflows in areas throughout the United States. As indicators of the errors associated with the estimates, NSS output may include standard errors of estimate and prediction, equivalent years of record, and/or 90-percent prediction intervals. The 500-year peak discharge can be compared to regional envelope values from USGS Water-Supply Paper 1887. Typical flood hydrographs for a given T-year peak discharge and flood-frequency curves can be obtained. Flood-frequency estimates for gaging stations can be obtained by determining the weighted average of estimates obtained from data for the stations with estimates obtained from regression equations, with weights based on the years of record at the gaging station and the equivalent years of record for the regression estimates. Flood-frequency estimates for ungaged sites can be obtained by combining the estimates from regression equations with estimates based on the flow per unit area for an upstream or downstream gaging station. B. DOCUMENTATION Documentation of the program history, content, theory, and application, including a users manual, is contained in: Ries, K.G., III, 2006, The National Streamflow Statistics Program: A Computer Program for Estimating Streamflow Statistics for Ungaged Sites: U.S. Geological Survey Techniques and Methods Report TM 4-A6, 42 p. Documentation of the equations, maps, and other information needed to solve the regression equations for individual States is provided on line through links from the NSS web page (http://water.usgs.gov/software/nss.html) to the complete original State reports, fact sheets, or still-current pages from the report: Jennings, M.E., Thomas, W.O., Jr., and Riggs, H.C., 1994, Nationwide Summary of U.S. Geological Survey Regional Regression Equations for Estimating Magnitude and Frequency of Floods for Ungaged Sites, 1993: U.S. Geological Survey Water-Resources Investigations Report 94-4002, 196 p. Known issues are posted directly on the NSS downloads webpage. C. HARDWARE AND SOFTWARE REQUIREMENTS NSS requires a computer running Windows XP (or newer). Adobe Acrobat Reader is required to display or print the User Manual in PDF format; however, the User Manual is available in other formats in addition to PDF. Microsoft Internet Explorer version 5.0 or newer is required to invoke the on-line help section. Less than 30 MB of free disk space is required to install and run the program with its associated database. D. INSTALLATION The installation program, NSSv6.x.exe, and the Access database, NSSv6_YYYY-MM-DD.mdb (where YYYY is the year, MM is the month, and DD is the day of the most recent release) should be downloaded to a temporary location on the user's computer. Because the files are large, installation problems can often be traced to incomplete downloads. File sizes for the database and program installer files are listed on the NSS downloads website for comparison. The user will need administrative privileges to install the program. To install the program, double-click on NSSv6.x.exe. An installation wizard will appear and prompt for a directory in which to save the program and whether or not to create a desktop icon. Follow the prompts provided by the wizard to install the program. When installation is complete, the directory that contains the program will include the following files: - NSS.lnk Shortcut (link) to the NSS program - unins000.exe Program that uninstalls StreamStatsDB - unins000.dat Used by unins000.exe - bin Folder containing the NSS executable and help files - data Folder that can be used to hold the NSS database file The user will need full access rights to the NSS parent directly and its subdirectories in order to use NSS. The user should copy the NSS database file to the data directory after the program is installed. In addition, if users choose to run region-of-influence regression for a state, they should download the one or two binary data files needed for region-of-influence for that state from the NSS Web page and place the files in the data directory where NSS is installed. E. RUNNING NSS NSS can be started by three methods, (1) select NSS from the Programs submenu of the Start menu, (2) double-click on the desktop icon, or (3) double-click on the program name (NSS.exe) in Windows Explorer or My Computer. After running NSS for the first time, a file named current.nss will be created in the NSS bin sub-directory. This file tracks user-provided instructions from the past session. Results of the work from the previous session will be displayed in NSS when the program is started again. Please check the known issues list posted on the NSS downloads page before using NSS. It is also recommended that users of NSS become familiar with the reports regarding the equations that they will be using. Links to the reports can be found on the NSS publications webpage at: http://water.usgs.gov/osw/programs/nss/NSSpubs_Rural.html F. HELP FILE The Help file provides full documentation on use of the program. The Help file can be started by clicking on the Help menu toward the top left of the NSS main window, or it can be started before running NSS by double-clicking on NSS.chm in Windows Explorer or My Computer. Users should thoroughly read the information in the Help file before trying to use the interface. G. VERSION HISTORY Version history can be found on the NSS website at: http://water.usgs.gov/osw/programs/nss/history.html H. DATABASE The NSS database is a Microsoft Access database that is write protected so that users cannot change the data. The database is updated as needed whenever new equations are added and links to the documentation for the new equations are provided from the NSS web site. Users should check periodically to determine if the database has been updated with new equations for their areas of interest. I. CONTACTS Inquiries about this software should be directed to: Todd Koenig U.S. Geological Survey 1400 Independence Road, MS 100 Rolla, MO 65401 E-mail: tkoenig@usgs.gov Phone: 573-308-3924