NFF National Flood Frequency Program NFF - Version 3.2, 2004/09/29 TABLE OF CONTENTS A. DESCRIPTION B. DOCUMENTATION C. HARDWARE REQUIREMENTS D. INSTALLATION E. RUNNING NFF F. HELP FILE G. VERSION HISTORY H. DATA BASE I. CONTACTS A. DESCRIPTION NFF is a Windows program for estimating the magnitude and frequency of peak discharges for unregulated rural and urban watersheds. NFF includes about 2,065 regression equations for 289 flood regions nationwide. Peak discharges with recurrence intervals between 2 and 500 years are estimated by regression equations or statistical extrapolation. 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-frequeny curves can be obtained. 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. 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, and Crouse, M.Y., 2002, The National Flood Frequency Program, Version 3: A Computer Program for Estimating Magnitude and Frequency of Floods for Ungaged Sites: U.S. Geological Survey Water-Resources Investigations Report 02-4168, 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 NFF web page (http://water.usgs.gov/software/nff.html) to the complete original State reports, fact sheets, or still-current pages from the report for the previous version of NFF: 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. C. HARDWARE REQUIREMENTS NFF requires a computer running Windows 98 (or newer), or Windows NT Version 4.0 with service pack 5 (or higher). 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. The amount of free disk space that is required varies greatly depending on the amount of station data stored in database files. For optimal performance, a processor running at 400 megahertz or faster with at least 128 megabytes of memory is recommended. D. INSTALLATION The installation program, NFFv3_2.exe, and the Access data base, NFFv3_2.mdb, should be downloaded to a temporary location on the user's computer. To install the program, double-click on NFFv3.exe in Windows Explorer or My Computer. 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. It is recommended that the directory for saving the program be named NFF and that the icon be created. 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: - NFF.exe NFF program - ATCoRend.mdb Database of colors used for graphics - current.nff Program that tracks changes made - unins000.exe Program that uninstalls StreamStatsDB - unins000.dat Used by unins000.exe - NFF.chm Help file The NFFv3.2_2004-09-29.mdb file should be copied to this directory after the program is installed. E. RUNNING NFF NFF can be started by three methods, (1) select NFF from the Programs submenu of the Start menu, (2) double-click on the desktop icon, or (3) double-click on the program name (NFF.exe) in Windows Explorer or My Computer. After running NFF for the first time, a file named current.nff will be created in the NFF directory. This file tracks user-provided instructions from the past session. Results of the work from the previous session will be displayed in NFF when the program is started again. 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 NFF main window, or it can be started before running NFF by double-clicking on NFF.chm in WinWindows Explorer or My Computer. Users should thoroughly read the information in the Help file before trying to use the interface. G. VERSION HISTORY Version 3.2 - 2004/12/9 - Updated the database to NFFv3.2_2004-12-14.mdb. Added new peak-flow equations for Connecticut and Kentucky. Corrected an error in the units displayed for conveyance in the Houston urban equations from in/hr to cubic feet per second. Corrected an error in the Wisconsin Area 1 equation for the 5-year recurrence interval. Version 3.2 - 2004/09/29 - Updated the database to NFFv3.2_2004-09-29.mdb. This database contains new peak-flow equations for Alaska, Idaho, Ohio, Tennessee, Vermont, Wisconsin, and Wyoming. Along with the new database comes the ability to display 90-percent prediction intervals with the estimates for some of the updated States. Version 3.2 - 2003/04/30 - Fixed a problem with the weighting function for gaging stations when there are no equivalent years for the regression estimates. This version also handles the case of a scenario with regions containing different sets of return intervals. It now reports why this can't be done and recovers much better. No updates to the database were made. Version 3.1 - 2003/02/27 – Fixed a problem with solving the national urban equations that occurred when one or more of the local rural equations were missing for the region of interest. If a rural equation, such as the 5-year flow, was missing NFF would use the flow estimate for the next available recurrence interval, such as the 10-year flow, to estimate the urban flow for the missing recurrence interval. All estimates for higher recurrence intervals would also be incorrect. Version 3.0 - 2002/10/15 - A major change in converting user the interface from Microsoft DOS to Microsoft Windows and converting data base from a binary file to Microsoft Access (Note: Use of trade or product names is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey). Addition of weighted estimates for ungaged sites based on regression estimates for the site of interest and the flow per unit area for an upstream or downstream gaging station. Updates or corrections to equations were included for Alabama Minnesota Alaska Missouri American Samoa Nebraska Arizona Nevada Arkansas New Mexico Colorado North Carolina - rural and urban Delaware Oklahoma Georgia - rural and urban Pennsylvania Hawaii Puerto Rico Idaho South Carolina - rural and urban Iowa South Dakota Kansas Texas - rural Kentucky - Jefferson County urban Utah Louisiana Virginia Maine Washington Maryland West Virginia Version 2.0 - 1996/09/15 - A non-USGS release that added conversions between English and metric units. Version 1.4 - 1996/09/30 - NFF data base updated to amend incorrect values for: - New Jersey--the constant 1 was removed from being added to the actual value entered for impervious cover, I - New York-- incorrect exponents and an incorrect regression constant were corrected for Region 6's 25-year and 500-year equations, respectively - Wisconsin-- the constant -2.3 was added to the data base to be applied automatically to the actual value entered for 2-year 24-hour rainfall, INTENS, for Areas 1, 3, and 5; incorrect exponents were corrected for Area 3's 5-, 25-, 50-, and 100-year equations Version 1.3 - 1996/02/14 - Corrected labeling of flood-frequency recurrence intervals for North Dakota. The equations developed for North Dakota are for the 2-, 10-, 15-, 25-, 50-, 100-, and 500-year recurrence intervals rather than the standard 2-, 5-, 10-, 25-, 50-, 100-, and 500-year intervals. Version 1.2 - 1995/06/02 - NFF data base updated to amend incorrect exponents in West Virginia's Region 6 equations for the 2-year and 10-year recurrence interval. Version 1.1 - 1994/11/21 - Initial release. H. DATA BASE The NFF data base is a Microsoft Access data base that is write protected so that users cannot change the data. It is planned that, rather than releasing a new version of NFF each time new equations become available, the NFF data base will be updated and links to the new documentation will be provided from the NFF web site. Users should check often to determine if the data base has been updated with new equations for their areas of interest. I. CONTACTS Inquiries about this software should be directed to: U.S. Geological Survey Electronic mail: kries@usgs.gov Office of Surface Water Fax: 703-648-5722 Kernell Ries Phone: 703-648-5307 12201 Sunrise Valley Dr., MS 415 Reston, VA 20192