Case Studies in the Use of Adaptive Management in the Total Maximum Daily Loads

The development of TMDLs, or Total Maximum Daily Loads, is often hindered by unproductive debate over uncertainties that are introduced due to unrealistic schedules, limited data, poor understanding of the linkage between sources and water quality targets, limitations of current models that are used to develop load allocations, or inappropriate water quality standards. Furthermore, resources to implement the TMDL may be limited and the most promising reductions may be attributed to nonpoint sources, where the regulatory framework cannot be used to ensure that implementation will occur on schedule, if at all. Therefore, for certain pollutants and watersheds, it can be extremely challenging to establish a definitive allowable loading limit that is needed to meet water quality standards when too much is unknown or uncertain.In response to these challenges, a few States and EPA regions have turned towards adaptive management to develop and implement TMDLs. Adaptive watershed. There have also been several calls for adaptive management to be incorporated into the TMDL program (Kitzhaber & Gering, 1998; Hammerschmidt, 2000; NRC/NAS, 2001). The Water Environment Research Foundation (WERF) recently funded a research project that recommended the necessary elements of adaptive watershed management for incorporation into the TMDL program (LTI, et al., 2003). This paper is an outgrowth of the WERF research cited above and a paper submitted at the TMDL 2002 conference (Freedman, et al., 2002). It provides more specific and detailed information on existing TMDLs that have used adaptive watershed management. In the past year, EPA issued a report on research needs to improve the TMDL process called “The Twenty Needs Report: How Research Can Improve the TMDL Program (EPA, 2002a). EPA noted in this report that adaptive approaches were unlikely to occur in the TMDL program unless there were more good examples. This paper provides examples.