Significant vector populations of mosquitoes, rats, and flies exist in the Basin and constitute a serious public health hazard. These vectors, especially mosquitoes and rats, are directly associated with the organic pollution present in the waters of the Basin. This pollution is instrumental in creating and supporting the present high population levels of disease-carrying vectors, particularly in the Denver Metropolitan area. Future vector population levels will remain high as long as significant quantities of organic pollutants are discharged to the waters of the Basin. Reduction or elimination of present vector populations will best be accomplished through the abatement or elimination of the gross organic pollution now being discharged to receiving waters throughout the Basin.