Maine's Statewide TMDL Approach, the Easy Way Out?

Maine DEP has been working with USEPA to develop statewide TMDL's approaches for 303d listed waters that share the same impairments. In 2009 USEPA approved Maine's Statewide Bacteria TMDL that covered all freshwater and marine listed segments, including both point and nonpoint sources. Besides setting TMDL water quality targets, the document is an overview of Maine's water quality standards and the various state programs designed to address different types of bacterial contamination. Maine is currently developing a statewide approach for urban streams that are impaired for aquatic life using the Impervious Cover Method(IC). Maine has had success with EPA approval of IC TMDLs on waters where urban stormwater is designated as the cause of observed impairments. The IC TMDL is a relatively simple GIS analysis that uses impervious cover as a surrogate for stormwater impacts, which has been linked directly to Maine's macroinvertebrate sampling results. This TMDL defines a %IC targets and identifies the pollutant load as the existing %IC in the watershed. The wasteload and load allocations are defined as the %IC reductions needed to achieve the target, but attainment of water quality standards is the ultimate goal. The %IC reductions also serve as a restoration concept for the adaptive implementation of BMPs within the watershed. The statewide TMDLs also cover all waters listed in the future for the same impairment, or the TMDL ‘that keeps on giving’. Questions remain on the value of the statewide versus individual waterbody TMDLs, but Maine believes this approach will shift the focus from TMDL development to watershed management and enable greater emphasis on restoration in the future.