WATER-RELATED INFORMATION SOURCES: HIGHLIGHTS by

Since the mid-1960's numerous technological developments in the machine-readable data base fielGI have had a decided impact on the types of search services provided to users. Far more data bases exist today than at any time in the past, and far more users are receiving search services from machine-readable data bases than at any time in the past (Williams 1975). Although there is not an accurate listing of all existing bibliographic machine-readable bases, the number would probably run close to 300.. Computer information systems are derived from a variety of sources, i ncl udi ng governmental agenc1es, abstracting and indexing companies, national or regional libraries, professional societies, ~niver~ities, public libraries, and private business firms. Although these base generators may differ 1n the1r data base formats and purposes, they all are interested in improving the dissemination of information. Historically, When co~ut:rs first started being used in connection with bibliographic information systems ~ t~ey were used pr1ma:11 ~ for SOl (selective dissemination of information) services (Mauerhoff 1974, W1ll1ams 1975). The pr1nc1ple behind SOl is to develop an interest profile for a user--for exam~le, ev?potranspiration measur:ment studies for Southwest u.s. areas--and periodically run this prof1l ~ aga1nst ~he.current data f1le. The end product is a series of current references to articles or proJect descr1~t1ons?n that topic. When bases are first being developed, it is reasonable to us