An inventory of lakes and reservoirs in Oregon has been needed for many years. Records have long been collected throughout the State to assess the quantity and quality of water from streams, but few data have been collected on water stored in Oregon's lakes and reservoirs. Such data are essential for a complete evaluation of the total surface-water supply of the State and to provide a basis for answering questions about Oregon's lakes. Much of the information on lakes and reservoirs previously collected by Federal and State agencies has never been published. These data were compiled and used as a basis for collecting additional information. This report provides information for use by city, county, and State planning groups as well as for sportsmen, tourists, and others interested in preserving the recreational value of Oregon's lakes.
Because of the large number of lakes and reservoirs in Oregon, a single report covering the State would be bulky. Therefore, the best approach seemed to be to publish several volumes on a county or multicounty basis, and Clatsop, Columbia, and Tillamook Counties were selected for the first report. (See fig. 1.)
In addition to office compilation of existing data, most lakes were visited at least once. Visits were made in late summer or early fall when lakes were most accessible and when water temperature and biological activity are at a maximum. Some lakes previously studied by other Federal or State agencies and included in this report were not visited during the study.
