TAKEN FROM THE SOURCE SITE: http://phil.cdc.gov/ the Image Number is 8634. Details as on the source site: This historic 1917 map, which had been digitally enhanced an colorized, depicted the system of water intake, and sewer outlet into Lake Superior at Two Harbors, Minnesota. As was one of a series of instructional drawings, this image was used by the Minnesota Board of Health to train the state's public health workers. The purpose of these images, and the training was focused on protecting potable water supplies from bacterial contamination, due to incorrect disposal of waste, such as sewage, that might foul ground water, lakes, rivers, and streams. Creation Date: 1917