Tillamook Bay and several of its tributaries do not meet state and federal water quality standards for bacteria under the Clean Water Act. In streams and rivers, E. coli bacteria levels often exceed the recreational standard. In the bay, bacteria levels exceed the shellfish harvest standard, causing frequent closures of shellfishing areas. Bacteria contamination is a significant threat to public health and aquatic function, and originates from point and non-point sources in runoff from agricultural, urban, and residential land uses along the rivers.

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In 1999 the EPA Coastal Environmental Monitoring & Assessment Program (CEMAP) sampled fish tissue and sediment from approximately thirty-five sites in the Tillamook Bay.  Preliminary results of this study indicated that there was a possibility of elevated levels of pollutants in fish tissues.  TEP partnered with the Oregon Department of Environmental Quality (DEQ) to further investigate toxics in Tillamook Bay during the summer of 2006 by collecting bivalves (clams). This project seeks to determine whether bivalves have accumulated pollutants that could pose a threat to people who harvest clams from the Bay.

Excessive sedimentation has been identified as a key problem in the Tillamook Bay watershed, but there has not been a rigorous process available to identify potential impairment areas.  Recent technical advances led by the Environmental Protection Agency's (EPA) research division have now made sedimentation analysis possible using a process adapted from the Environmental Monitoring & Assessment Protocol (EMAP).  Applying this process, TEP is spearheading a collaborative project to characterize and monitor sedimentation throughout the watershed.

TEP and several partners are paying increasing attention to slough habitats and water quality.  In the summer of 2007, TEP and DEQ initiated a project to collect DO data from area sloughs to support DEQ's development of a DO standard and TEP's development of a "State of the Bay Report Card".  The Dougherty, Hoquarton, and Hall sloughs have been listed on DEQ's 303(d) list for limited DO, so these sloughs will continue to be the focus of monitoring activities.  Data will also be collected from Blind and Hall Sloughs. Data will also support a project that TEP is developing with ODFW to evaluate the impact of water quality on salmonid use of sloughs.

The purpose of this monitoring is to track critical summer water temperature for major rivers in the Tillamook Bay watershed.  The data will be used by TEP characterize baseline temperature, trend general water temperature, and to establish temperature trend in area where restoration activities have occurred.  TEP will also use the data to assess whether rivers in the Tillamook Bay watershed are meeting the State of Oregon water quality criteria to protect beneficial uses, Salmon.

• PEPA Study
• Salmonella in Surface Water