Despite supporting a wide variety of aquatic life, the Tualatin River and its tributaries sometimes violate the State of Oregon dissolved oxygen standard. In order to properly manage the Tualatin River and avoid future violations of the State dissolved oxygen standard, it is imperative to understand the relative magnitudes of the various sources and sinks of dissolved oxygen in the river.
SOD is partly due to biological processes and partly due to chemical processes.
SOD has been found to be an important sink for dissolved oxygen in a wide variety of surface waters. Prior to 1992, the magnitude of the SOD rate in the Tualatin River was unknown. Therefore, it was thought that reducing the amount of phytoplankton would result in a concomitant reduction in the impact of the SOD on DO concentrations. In order to manage the river for dissolved oxygen, it is necessary for USA managers to know the magnitude of the SOD rate, how it varies spatially and temporally, and whether that rate is influenced by decomposing algal detritus. This study of SOD was part of that larger investigation.