Annual surveys of fall chinook salmon in the Hanford section (Ringold to Priest Rapids) of the Columbia River have been conducted annually since 1947. Estimates of the relative numbers of fall chinook spawning in this section of the river are obtained through several aerial surveys made each fall. The possible relationships of environmental factors to the size of the local salmon population have been reported for the period 1947 to 1969 (Watson 1970) and each year's survey results are summarized in Battelle Pacific Northwest Laboratory Annual Reports to USERDA (formerly USAEC) Division of Biomedical and Environmental Research. This report was prepared to provide more detailed information than is available in previous reports on the timing of spawning in the principal breeding areas during recent years.