Dear AGNPS User: May 1995 We are pleased to announce the release of AGNPS version 5.00. This latest version of the single-event model has the same look as it's predecessor- -version 4.03b. Version 5.00 may be downloaded from our anonymous ftp site by executing the following commands at the ftp prompt: "open ftp.mrsars.usda.gov" , "anonymous" , "your E-mail address" , "cd pub/ars/agnps" , "bin" , and "get about.txt" . Once you have downloaded this file, please read The basic processes of the AGRUN component for AGNPS version 5.00 (water, sediment, and chemicals) have been verified and corrected. Also, the spreadsheet has been revised to read the input data files for AGNPS version 4.0 and greater as if they were 5.00. Conversions from the earlier versions to 5.00 are still permitted. The spreadsheet was not verified although it contains some flaws (e.g., does not re-initialize when options are changed). Problems are known to occur when utilizing the spreadsheet editor for a large number of cells. It is recommended that the spreadsheet not be used for modeling large watersheds. Detailed verification reports are available with the distribution files. The reports are: (a) AGNPS Version 5.00 Verification Report: Science (science report); and (b) AGNPS Version 5.00 Verification Report: Software (software report). Only the chemical & sediment trap components required correction because of failure to satisfy the science. Also, some corrections were made to correct software-related problems. Some of the reported errors with the sediment trap feature may have been the result of confusion with respect to the input requirement for channel length. Users often confuse segment with total channel length. A warning message was added for some situations that had previously resulted in operational errors and lockups. Division by zeros and some extended memory problems were corrected, however, we were unable to correct virtual memory problems. Testing showed that the program was able to handle at least 16,384 cells on DOS PC's with 8 or more Mb of RAM configured solely for AGNPS. More extended memory did not permit a greater number of cells. The UNIX version of AGRUN uses the same corrected source code as the DOS version 5.00 and has been tested successfully for up to the 32,767 integer limit for the maximum number of cells. We have included verification output files to version 5.00. These files were designed for limited testing purposes only and will not be of use for actual data. They are described in detail on pages 1-4 of the software report. All divide by 0 errors encountered during testing were corrected, however potential situations still exist. As a rule, if a divide by 0 error is encountered, check the channel geometry inputs for 0 values. For more information on potential divide by 0 errors, see page 5 of the software report. This summarizes the revisions for the AGNPS version 5.00 May 1995 release. The AGNPS User's Guide and the AGNPS Help Screens did not need to be revised for content so they were not changed to reflect the new version number. Version 4.03 of the user's guide and help screens are still valid for version 5.00. Please read the AGNPS User's Guide before using the AGNPS version 5.00 program. No further revision will be made in the single event version. Respectfully, Fred D. Theurer Ward B. Voorhees ANNAGNPS Project Manager Research Leader