Historical Information on Washington State’s Water Quality Assessments, 303(d) Lists and 305(b) Reports

The Water Quality Assessment

Water quality reporting is a requirement of the federal Clean Water Act (CWA). Since the first reporting in the 1990s, Congress receives at least two reports every two years. The most significant report is required by section 303(d) of the CWA, known as the 303(d) list. It is to be prepared every two years, and include the waters of the state that do not meet water quality standards after initial National Pollutant Discharge Elimination System (NPDES) permits are in place. The other report EPA submitted to Congress is a more general report on the overall quality of the nation's waters, required by section 305(b) of the CWA and broken down by state. In 2002, EPA directed the states to combine the two reports into one and called it the “integrated report.”

During the 2002-2004 development of Washington State's integrated report Ecology modified how water quality data was formatted. Using geographic information system (GIS) layers, Ecology grouped data into categories, with categories 1-4 representing the 305(b) report, and category 5 representing the 303(d) list. Washington State decided to call its integrated report "water quality assessment".

The 303(d) List

The most significant report required by section 303(d) of the CWA is known as the 303(d) list. It is to be prepared every two years. It lists the waters of the state that do not meet the water quality standards after initial National Pollutant Discharge Elimination System (NPDES) permits are in place.

Based on previous 303(d) lists, the primary water quality problems in our state’s waters were temperature and fecal coliform bacteria. Both are generally associated with nonpoint source pollution – that is, pollution which comes from many diffuse sources, not just from the end of a pipe.

Temperature is significant for the health of aquatic life. Salmon, especially, and other fish need cooler temperatures to survive and spawn. High temperatures can occur due to the discharge of hot water from power plants and industrial sources or, more often, from loss of vegetation along streams that used to shade the water and from new land uses (buildings and pavement) from which rainfall picks up heat before it runs off into the stream.
Fecal coliform bacteria is significant for human health as an indicator of the presence of disease-carrying organisms. It commonly comes from livestock and failing septic tanks.

Other water quality problems which lead to 303(d) listings in Washington State include:

Toxic substances from industrial and other sources, which can collect in sediments on the bed of the water or in the tissues of aquatic life.
Erosion from roads, construction, and agriculture, which increases sediment in streams that can cloud the water and cover aquatic habitat.
Too much organic waste decaying in the water, which can lower the levels of dissolved oxygen that fish and other aquatic creatures need to survive.
Excessive nutrients, such as phosphorus and nitrogen, are the primary problem in Washington's lakes. Sources include irrigated agriculture, gardening practices, and urban and suburban property development. The nutrients cause algae and other aquatic plants to grow in lakes, which deprive aquatic life of vital oxygen. Algae can also make lakes unusable for recreation.

303(d) Lists for Previous Years

2004 - current: covered in the Water Quality Assessment as category 5 listings visible in the simple query tool.

2000: EPA did not require a report for 2000.

1998 303(d) List.

1996 303(d) List.

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The 305(b) Report

The Section 305(b) report, required by the CWA, describes the current conditions of the state's waters to the U.S. Congress and the public. It is a state-wide narrative assessment of the status of all the state's waters, whereas the 303(d) list reports just on the impaired waters of the state.

305(b) Reports for Previous Years

2004 - Present: covered in the Water Quality Assessment as category 5 listings visible in the simple query tool.

2002 305(b) Report.

2001 305(b) Report.

2000 305(b) Report.

1998 305(b) Report (PDF).

Last updated May 2011