Water temperature in tributaries, off-channel features, and main channel of the lower Willamette River, northwestern Oregon, summers 2016 and 2017

Abstract

The U.S. Geological Survey collected continuous water-temperature data in select tributaries of the lowermost 80 kilometers (50 miles) of the Willamette River in northwestern Oregon, during summers 2016 and 2017. Point measurements of water temperature and water quality (dissolved oxygen, specific conductance, and pH) also were collected at multiple locations and depths within the river and in the lower reaches of three major tributaries (Clackamas and Molalla Rivers, and Johnson Creek). These datasets were collected to identify potential locations of cold-water refuges for sensitive fish species, and to characterize daily, seasonal, and spatial variability in water conditions. These datasets may be useful for local municipalities that are required to identify cold-water refuges (as defined in State of Oregon water-quality standards) and determine approaches for protecting and enhancing these features as part of their Willamette River water-temperature Total Maximum Daily Load implementation plans. This report documents the data collection methods, provides summary graphs and maps of the water-temperature data, and outlines steps for accessing the data.