The purpose of the study is to seek out locations in Toronto where water quality requires improvement, and to develop cost-effective measures for achieving that improvement. The study's overall goal is to produce a comprehensive water quality management plan for the Toronto area watershed, with particular emphasis on the Don and Humber Rivers and Mimico Creek. This report summarizes work carried out in the first year of TAWMS which was directed towards a closer definition of existing water quality conditions within the study area. The work relied heavily on historical and recent water quality data collected through the routine sampling programs of MOE and other agencies, but also made use of information from a limited sampling program undertaken by TAWMS in 1981 to supplement the routine data base.