TMDLs (Total Maximum Daily Loading) define how much of a pollutant a water body can tolerate on a daily basis & still meet the relevant water quality standards. All of the sources of the pollutant in the watershed combined, including non-point sources, are limited to discharging no more than that total limit. EPA is suing states to force them to produce TMDLs. A growing number of California's water bodies are either subject to consent decrees to develop TMDLs, or are the subject of notices of intent to file lawsuits that may have that outcome. This report addresses California's many problems in establishing TMDLs for its impaired water bodies.

The definitive guide to all there is to know about the TMDL requirements of clean water legislation.

Narrative water quality criteria are an integral component of States water quality standards but they pose special problems when incorporated into the TMDL process. The TMDL process is typically a quantitative activity, defining numeric allowable loads necessary to meet a numeric water quality objective. Narrative criteria confound development of quantitative TMDLs, due to the absence of these numeric criteria. The objective of this research was to improve the methods for addressing narrative water quality criteria in the TMDL process. The problems associated with narrative criteria in the TMDL process are known in general terms but, prior to this research, there has not been a thorough review of the use of narrative criteria in TMDLs nor broad guidance on how to address narrative criteria in the TMDL process. The approach taken for this research was to define the range of problems associated with all types of narrative criteria by means of a comprehensive review of 120 narrative TMDLs, and provide guiding principles to help address these problems.