Total maximum daily load (TMDL) approach to surface water quality management: concepts, issues, and applications

The total maximum daily load (TMDL) approach is an emerging paradigm in surface water quality management and has been adopted and applied in many states in the US. The paper explains the conceptual development of the general TMDL process for surface water quality management of three water quality impairment constituents, namely, nutrients, pathogens, and acid load. The application of the TMDL approach to a stream impaired due to high acidic concentrations from mine drainage in southeastern Kentucky is explained and used to demonstrate the complete development of the TMDL process. The paper highlights a number of issues, ranging from assessment of pollution-causing sources to development of practical methods for implementation of TMDLs.