USGS Washington Water Science Center
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9722-9EL - Dissolved Oxygen Monitoring and Profiling in the Lower Puyallup and White Rivers to Help Address TMDL-Related Questions - Completed FY2002
Introduction and Background - Monitoring conducted by the USGS in cooperation with the Washington State Department of Ecology (Ecology) and the Puyallup Tribe of Indians found that the concentration of dissolved oxygen in the White River dropped below the standard of 8 milligrams per liter (mg/L) on two occasions during August 2001. This confirmed that there is little or no reserve capacity for biochemical oxygen demand in the lower White River. On both occasions when the concentration of dissolved oxygen dropped below 8 mg/L, the quality of the monitoring record was rated as poor because of difficulty with instrument calibration. Consequently, Ecology and the Puyallup Tribe are interested in monitoring concentrations of dissolved oxygen in the lower White River again in August and September 2002.
The reach of the Puyallup River downstream from river mile (RM) 2.9, which is where monitors were installed in 2000 and 2001, is a salt-wedge estuary and therefore is a transitional area where the water-quality standard of 8 mg/L for dissolved oxygen in freshwater changes to 6 mg/L in saltwater. To better understand the effects of mixing of fresh and salt water on concentrations of dissolved oxygen, the Puyallup Tribe is interested making cross-sectional measurements of dissolved-oxygen concentrations and specific conductance at about RM 1.0 in the Puyallup River Estuary.
Objectives - The objectives of this study are to 1) better define variability in concentrations of dissolved oxygen in the lower White River, and 2) define cross-sectional variations in specific conductance and concentration of dissolved oxygen in the Puyallup River Estuary.
Relevance and Benefits - This study will address the second major mission goal of the USGS 2000-2005 Strategic Plan of better understanding the Nation's environment and natural resources. The study, which involves cooperative monitoring and data collection, will help to better understand how reservoir management affects dissolved-oxygen concentrations in the White River. Thus, it also addresses three of five water issues identified in the District Science Plan-water availability, hydroelectric power, and water quality. Locally, the data are very important to the Puyallup Tribe of Indians, Washington State Department of Ecology, and other parties who desire to resolve questions about waste load allocation limits in the lower White River.
Approach - This study will be a coordinated effort of the Washington State Department of Ecology (Ecology), Puyallup Tribe of Indians, and the USGS. Elements of this study include continuous monitoring, cross-section profiles, and data analysis and reporting.