EVALUATION OF POLLUTION LOADINGS FROM URBAN NONPOINT SOURCES: METHODOLOGY AND APPLICATIONS
Journal of Great Lakes Research , 15 , 1989

Marsalek, J., Ng, H.Y.F.

In preparation of remedial action plans for the St. Clair, Detroit, and St. Marys rivers, a planning-level methodology for evaluation of pollutant loadings from urban nonpoint sources was developed and applied in three Canadian cities: Sarnia, Sault Ste. Marie, and Windsor. This methodology uses computed annual volumes of runoff and mean constituent concentrations, estimated from field sampling, to produce estimates of annual pollutant loadings. For the constituents studied, the total loadings were predominantly from point sources in about three quarters of all cases. For some of the less common substances, occurring at low levels, the nonpoint sources contributed loadings which were comparable to or even higher than those from point sources. Such findings will be useful in the development ofremedial action plans which need to focus on control of pollutant sources.