Water quality assessment & 303(d) list

To develop the revised assessment, we first needed to review and update our water quality assessment policy (Policy 1-11). The purpose of the update was to include several revisions to Washington's surface water quality standards and respond to comments received in the public review of the policy.

Next, we gathered readily available data and narrative information to help us understand the condition of state water bodies. To do this we used federal databases and asked other groups to submit their data to our Environmental Information Management System (EIM). Our call for data and narrative information happened in 2018 and we recieved approximately 116 million pieces of data. The updated assessment will reflect all data and information collected through 2017. Water quality condition determinations based on data prior to 2006 are only reassessed if newer data and information are available.

We applied the updated Policy 1-11 to evaluate the data quality and used the data to review all of Washington's water bodies to determine where designated uses are impaired. The result is the draft revised water quality assessment. 

Due to the large volume of data that are available for Washington, we developed new data tools to automate much of our process. These tools will help us gather data more frequently and provide the Assessment to EPA every two years. The development and testing of these new automation tools was completed in Spring 2020 and are now being used to create the draft Water Quality Assessment. 

We held a public review of the draft assessment from April 8 to June 4, 2021. On April 20, 2021, we held a workshop to walk through the draft assessment. We highlighted the assessment process, key changes in this assessment, and provide a demonstration of how to use review tools and submit comments.

View presentation slides (pdf)

Next steps

EPA has 30 days from the time we submit the assessment to take action. We are working diligently with EPA to ensure a quick and smooth approval process. Following approval, the candidate list will become the new, approved Water Quality Assessment for Clean Water Act regulatory purposes. We will then announce a Call for Data for the next Water Quality Assessment cycle.

Category 1 means a water body meets the state water quality standards. Being placed in this category does not necessarily mean that a water body is free of all pollutants.

Most water quality monitoring is designed to detect a specific array of pollutants, so placement in this category means that the water body met standards for all the pollutants for which it was tested. Specific information about the monitoring results may be found in the individual listings.

Water bodies in this category have some evidence of a water quality problem, but not enough to show persistent impairment. These are water bodies that we want to continue to test.

There are several reasons why a water body would be placed in this category. A water body might have pollution levels that are not quite high enough to violate the water quality standards. Or there may not have been enough violations to categorize it as impaired according to our listing policy.

According to Policy 1-11, Category 3 water bodies have insufficient data to place them into any of the other categories.

Category 4 means water bodies that have impairment problems are being resolved in one of three ways:

• Category 4a — already has an EPA-approved TMDL plan in place and implemented.
• Category 4b — has a pollution control program, similar to a TMDL plan, that is expected to solve the pollution problems.
• Category 4c — is impaired by causes that cannot be addressed through a TMDL plan. Impairments in these water bodies include low water flow, stream channelization, and dams. These problems, while not pollutants, require complex solutions to help restore water bodies to more natural conditions.

Water quality assessment Category 4b

We recognize that communities do not have to wait for a formal TMDL planning process to begin improving water quality. They can take the initiative to clean up polluted water. Because these efforts are locally controlled, there is an opportunity to reduce overall costs, and the communities can exert greater control over the cleanup process.

Category 4b is intended for water bodies with a pollution control program in place that is expected to solve the pollution problems. While pollution control programs are not TMDLs they must have many of the same features. There must also be some legal or financial guarantee that the program will be implemented.

To be placed in the "has a pollution control project" category, the pollution control project must meet all of the following criteria:

• Be problem-specific and water body-specific
• Have reasonable time limits established for correcting the specific problem, including load reduction or interim targets, when appropriate
• Have a monitoring component to evaluate effectiveness
• Have adaptive management built into the plan to allow for course corrections, if necessary
• Have enforceable pollution controls or actions stringent enough to attain the water quality standard or standards
• Be feasible, with enforceable legal or financial guarantees that implementation will occur
• Be actively and successfully implemented and show progress on water quality improvements in accordance with the plan

In addition to the conditions above, the project is more likely to gain approval if the following elements are included:

• A description of management measures
• An implementation schedule and measurable milestones
• A description of criteria that are used to determine loading reductions achieved over time
• An information/education component

This is the list of impaired water bodies traditionally known as the 303(d) list. Starting with the 2004 Water Quality Assessment, Washington’s 303(d) list of polluted waters were placed under category 5 in the approved assessment. Total Maximum Daily Loads (TMDLs) or other approved water quality improvement projects are required for the water bodies in this category.

If a water body is in this category it means that we have data showing that the water quality standards have been violated for one or more pollutants, and there is no TMDL — or pollution control program — in place.