Along the length of the pipe were outlets to which thick rubber tubing was connected, each tube to a pump.
At the same time it built great dams across the outlets which raised the surface of the water to a much higher level and caused them to form new outlets, thus changing the whole face of the country over which the ice drifted.
The great lakes, that were enlarged during the glacial period and in some cases wholly created--by the scooping out and damming up of the waterways and by piling glacial drift around their shores--have had some of their outlets raised to a higher level, and others have been created anew.