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Background
The 1998 Water Quality Assessment (303[d]) list was based on a major change to the segmentation system used to identify impaired waters. In previous lists, whole waterbodies or major sections were listed based on sampling from limited areas within the waterbody. In order to more accurately represent the area of a waterbody that data indicated was impaired, the 1998 segments were limited to the portion of the waterbody located in the same section (township/range/section) as the sample data location.
The Washington Department of Ecology submitted its Candidate 1998 Section 303(d) List to the U.S. Environmental Protection Agency (EPA) on June 29, 1998. On August 26, 1999, Ecology received a partial approval/disapproval letter (PDF) from EPA in response to the list. EPA approved the list that Ecology submitted and proposed adding an additional 130 waterbody/parameter combinations to the list. On January 28, 2000, EPA transmitted their final response to Ecology. As a result of EPA's action, Ecology added 116 new waterbody/parameter combinations to the list.
The 1998 list included a total of 643 impaired waterbody segments out of the 1,099 for which Ecology had data, many of which violated standards for more than one pollutant. (The 643 represented only about two percent of all the waters in Washington.) The waterbodies measured were generally those with a history of pollution. (In 1996 we listed 666 segments representing 611 whole waterbodies. The number of whole waterbodies on the 1998 list increased by 32 over the 611 on the 1996 list).
Bacteria violations accounted for 285 listings, while temperature affected a total of 282 waters. Dissolved oxygen impaired 133 waterbodies, and pH effected 87 waterbodies. Seventy-eight waterbodies suffered from elevated toxics and 28 had too many nutrients. A total of 38 waterbodies were listed for low flow problems.
Because of public comments, Ecology added 234 waters to the proposed list, based upon new information. Ecology also removed 210 waters because new information showed those waters were meeting water quality standards, or they had an adequate management plan to address the water quality problem.
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