Integration of data and component models describing habitat-based land use, non-point source pollutants transport, and water and soil quality forms the decision support development processes to assist policy makers in examining management options for dealing with the impacts of land use on water for agricultural issues in Canada. The land and water integration decision support system emphasizes on scale consistency, scenario gaming and testing, pollutant source tracing and optimal solutions. Examples of a watershed-based decision support system on water quality impact were presented as part of an assessment for the evaluation of best management practice options for future agricultural intensification scenario.