Impairment of water quality is major concern for streams and rivers in China.Total maximum daily loads (TMDLs) establish a framework and propose a series of techniques and tools to assess water quality in watershed scale.With the development of TMDLs,some programs and strategies like TMDLs are proposed by EPA,scientists and stakeholders,how to calculate TMDL and consider its seasonal variations efficiently and accurately with minimal data,has been a primary problem for TMDLs development in China.