The assessed waters are now listed in five categories that describe the status of water quality. Waters that have data showing they are polluted are in Category 5, which indicates that beneficial uses such as drinking, recreation, aquatic habitat, and industrial use are impaired by pollutants. Category 5 represents the 303(d) List. A description of each category is as follows:
The new list will divide water bodies into one of five categories:
Category 1: Meets tested standards. Placement in this category means that the waterbody segment meets the criteria it was tested for. It 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.
Category 2: Waters of concern. This category lists waterbody segments where there is some evidence of a water quality problem, but not enough to require production of a TMDL. 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 Ecology?s listing policy. There might be data showing water quality violations, but the data were not collected using proper scientific methods. In all of these situations, these are waters that we will want to continue to test.
Category 3: No data. This category will be largely empty. Water bodies that have not been tested will not be individually listed, but if they do not appear in one of the other categories, they are assumed to belong in Category 3.
Category 4: Polluted waters that do not require a TMDL. This category is for waterbody segments that have pollution problems that are being solved in one of three ways.
Category 4a is for waterbody segments that have an approved TMDL in place and are actively being implemented.
Category 4b is for waterbody segments that have a pollution control plan in place that is expected to solve the pollution problems. While pollution control plans are not TMDLs, they must have many of the same features and there must be some legal or financial guarantee that they will be implemented.
Category 4c is for waterbody segments impaired by causes that cannot be addressed through a TMDL (not due to a pollutant). These impairments include low water flow, stream channelization, and dams. These problems require complex solutions to help restore streams to more natural conditions.
Category 5: Polluted waters that require a TMDL. Category 5 represents the 303(d) list, the traditional list of impaired water bodies. Placement in this category means that Ecology has data showing that the water quality standards have been violated for one or more pollutants, and there is no TMDL or pollution control plan. TMDLs are required for the water bodies in this category.
The results of Washington's Water Quality Assessment have been submitted to the Environmental Protection Agency (EPA) to satisfy federal Clean Water Act requirements of sections 303(d) and 305(b). EPA refers to this assessment as an integrated report to meet these requirements. On November 4, 2005, EPA approved Category 5, which represents the 303(d) List. A water cleanup plan, also known as a total maximum daily load or TMDL, must be developed for each of the water bodies on the Category 5 list. The cleanup plan identifies how much pollution needs to be reduced or eliminated to achieve clean water.
The last polluted waters list was done in 1998. Following guidance from the U.S. Environmental Protection Agency, the current listing process includes a much more comprehensive assessment of Washington's waters.