Water-Resources Investigations Report 93-4076, Hydro-Climatic Data Network (HCDN): Streamflow Data Set, 1874-1988 In Reply Refer To: July 20, 1993 Mail Stop 415 OFFICE OF SURFACE WATER TECHNICAL MEMORANDUM NO. 93.20 Subject: Water-Resources Investigations Report 93-4076, Hydro-Climatic Data Network (HCDN): Streamflow Data Set, 1874-1988, by J.R. Slack, Alan M. Lumb, and Jurate Maciunas Landwehr This memorandum is to announce the availablity of the subject report and to make a distribution to Districts and other selected offices. This Water-Resources Investigations Report is unique in that it is a CD-ROM. The only printed text is that on the front and back cover sheets of the protection case. The data set on the CD-ROM consists of a cumulative 73,231 water years of daily, monthly, and annual streamflow data collected during 1874-1988 at 1,659 stations. These stations, called the "Hydro-Climatic Data Network (HCDN)," were selected from the total network operated over the years by the U.S. Geological Survey (USGS). Criteria for selection were established for climatic analysis and were intended to minimize effects due to human activities, provide long and accurate records, and give reasonably complete geographical coverage of the United States. Researchers and other investigators are expected to use this data set where high-quality, long-term streamflow records with a minimum of anthropogenic effects are needed for regional or national analyses. The HCDN is the first national network of stations the USGS has selected that has data suitable for climatic and other similar analyses. The CD-ROM presents data as three formats: a text file, a straight-forward binary, and a database for use with the USGS Watershed Data Management System. The data in text-file format are readable on IBM-compatible personal computers, Data General work stations, and Macintosh computers. However, the other two formats and accompanying software are made available only for IBM-compatible computers. Copies of the CD-ROM may be obtained from the authors or from the Office of Surface Water (OSW). The contents of the CD-ROM can be accessed over Internet via anonymous ftp (file transfer protocol) to directory hcdn92 at <ftp://ftpext.usgs.gov/pub/er/va/reston/hcdn92/>. A companion document to the CD-ROM, in which the contents of the HCDN are defined, was announced in OSW Technical Memorandum No. 93.02. It is Open-File Report 92-129, Hydro-Climatic Data Network: A USGS streamflow data set for the United States for the study of climatic variations, 1874-1988, by J.R. Slack and Jurate Maciunas Landwehr. An electronic copy of the Open-File Report is contained on the CD-ROM. Paper copies are available from the authors or from the OSW. Charles W. Boning, Chief Office of Surface Water WRD DISTRIBUTION: FO Chief, Branch of Regional Research, NR, CR, WR (2 copies each) Regional Surface Water Specialists, NR, CR, SR, WR