A great variety of hydrologic data are collected by many governmental agencies and other entities for diverse purposes. Some of the data are compiled and reported in readily available, widely known publications; some are not. Continuing requests for information on the locations of data collection sites and on the sources of data have suggested the need for a guide to that information.
Presently active primary-data-collection sites have been located on a map of the Greater Pittsburgh region (Allegheny, Armstrong, Beaver, Butler, Washington, and Westmoreland Counties in southwestern Pennsylvania), and the sources of data--by publication or responsible agency-have been described. Secondary data collection sites have not been shown on the map, but several agencies involved in this activity have been listed.
Hydrologic data are collected at the following numbers of identified sites under the auspices of federal, state, and interstate organizations:
Precipitation or temperature .......... 39
Surface-water stage or discharge ...... 82
Surface-water quality ................. 69
Ground-water levels ................... 7
