Distributed nonpoint source simulation model - case study in Thames River Basin of Canada

A mathematical model was proposed, based on a distributed runoff model and a geographic information system(GIS), to simulate nonpoint source pollutants losses. For model verification, a case study was carried out in the Thames River Basin in southern Ontario of Canada. The principal nonpoint source pollution in this area is pesticide losses from agricultural lands. Atrazine, a common-used pesticide, was selected as the simulation target. A comparison between observed and predicted data during May 1991 to April 1992 was conducted. The correlation co-efficients are over 0.9 and the statistical significance level was approximately 5%, indicating a reasonable prediction accuracy. The proposed model was proved to be valuable for predicting nonpoint source pollution and supporting relevant pollution control and management.