Beginning in water year 1998, the U.S. Geological Survey's Annual Water-Data Report for Illinois is being published in a substantially different form than previous printed versions. Numerous requests for hydrologic data in electronic format have shown a need to revise the way the report is published. Therefore, the report is being distributed on compact disc (CD) with limited paper copies available from the Illinois District office at the address given in the CD insert. The report also is provided on the Illinois District's Web page at http://www-il.usgs.gov/.
Using a CD provides the capability to present more data in new ways. The following is a list of new features that are not available from previous printed reports:
The report provides data in both traditional-table format (as published in previous reports) and in Relational Data Base (RDB) format. An RDB file consists of tabular data that can be transferred into common software packages for data processing and analysis. Unlike previous reports that grouped various data tables for each station in page order, the CD contains data grouped by data types, such as "Surface Water", "Ground Water", "Precipitation", and "Biological." Within each data type is a list of the stations that have data available for that data type. Previous printed reports have a table of contents listing stations and page numbers, whereas the CD contains station lists that can be sorted by station number or name. In addition to station manuscripts provided with the traditional data tables, station manuscripts are available separately for all stations. Station manuscripts provide descriptive information about each station, such as station location; period of record; historical extremes outside the period of record; record accuracy; and other remarks pertinent to the station. Refer to the section, "How to Use Data on this Compact Disc", for more details about how data are arranged on the CD.
Historic data are provided for the first time on this CD. Historic data consists of previously published data that are available from the Illinois District's computer system. In this current version, not all data types will have historic data. Plans are to include historic data stored on computer for all data types in subsequent reports. Historic data, as well as data for the current year, are provided in RDB format.
Also new are clickable maps in the data sections that show locations of stations for each data type provided for the current year. These maps allow a user to choose data by selecting (clicking on) a station on the map.
Mean-daily stage data for all gaging stations that have data stored in the Illinois
District's computer system are provided for the first time. These
stage data are available in traditional tables or RDB format.