The TMDL process starts with the Integrated Report. The Integrated Report is a comprehensive report on the quality of Oregon's surface waters every two years. Specifically, the Integrated Report puts assessed water bodies into categories based on the level of impairment, or pollution. There are five categories that range from “clean and meeting water quality standards" in Category 1, to “not enough data" in Category 3, to “not meeting water quality standards and requiring a TMDL" in Category 5. Those water bodies in Category 5 go onto a list of impaired water bodies, known as the 303(d) list for the section of the federal Clean Water Act that establishes this overall practice. The 303(d) list shows us which waterbodies are impaired.
The Integrated Report prioritizes the 303(d) list into a work plan for DEQ based on a variety of factors including risk to beneficial use, court ordered schedules, and permit issuance priorities. TMDL development priorities are documented in the Integrated Report and in the Performance Partnership Agreement between DEQ and EPA. DEQ's Water Quality Program then begins the process of developing the TMDL. Each TMDL project is unique, but there are essential elements to all TMDLs. These elements are identified in federal code and in Oregon state rule.