water. Subsequently, a tunnel was built to supply water to the south and east sides. This latter project cost one million dollars, the most expensive internal improvement yet in Chicago. 24
The development of the South Side created additional pollution problems in the Chicago River, which would again affect the drinking water supply. So, in 1866 construction was started to deepen the I. and M. Canal at the summit level; this was to erase the 10-foot rise between the lake and the canal 15 miles south. This, as has been noted above, was completed in 1872. Now the hydraulic problems of the City were united. Water transportation and sewage disposal were linked, though it is obvious that the latter interest was becoming more important.
By 1889 it was apparent that a deeper cut had to be made, as the Chicago River was again polluting Lake Michigan. As a result, the Chicago Metropolitan Sanitary District was created, and its purpose was to construct a canal of sufficient depth so that it could pull off Lake Michigan a maximum of 600,000 cubic feet of water per minute. This channel would go 28 miles to Lockport. It was completed in 1900, and its width and depth made it the biggest canal constructed in the 19 century. It was unique also that though proclaimed a navigable waterway, it was really a huge flushing operation, which had no navigable outlet until 1907 when the main channel was extended four miles and a powerhouse and a lock were built to make the Sanitary Canal and Ship a navigable waterway. 25
The construction of the Ship and Sanitary Canal necessitated cutting its base down 26 feet below the floor of Lake Michigan. This meant that the possibility existed of dropping the level of Lake Michigan and the other lakes so that the Niagara River would dry up. This theoretical possibility existed because Joliet was 40 feet below Lockport, six miles away. Therefore, the Sanitary District designed the controlling works at Lockport, so the lake extended 36 miles inland. The controlling works consisted of a “Bear Trap Dam” or a variable level dam that would rise and fall as the water level did. It also included a set of traintor or lift gates that could divert more water off the Sanitary Canal and into the Des Plaines River tail race. In constructing this canal, the Des Plaines River bed had to be moved in several sections between Chicago and Lockport. Besides this, the flow of the Chicago River was permanently reversed and its level raised. 26 This indicates how the hydraulic city was extending its water tentacles in an even more important way than when the “deep cut” was made in 1871 allowing a direct connection between Lake Michigan and the I. and M. Canal. All of these developments relate to the unique geographical location of Chicago, that is, the small elevation and distance separating Lake Michigan and the Mississippi drainage in that city area.
After the completion of the Sanitary and Ship Canal, the Sanitary District realized it had certain inadequacies. First of all, it was not navigable, and therefore objections were raised that Chicago was diverting water from Lake Michigan for non-navigable reasons; secondly, it was obvious that much of the increased flow in the Des Plaines caused by the diversion could be used to produce hydro-electric power. Finally, there were complaints from Joliet particularly that not only was Chicago sending its sewage downstate, but was also endangering Joliet, because if the controlling works at Lockport failed, Joliet would be engulfed with thousands of feet of lake water, as it was about 40 feet below those controlling works.
For these reasons between 1903 and 1907, the main channel was extended four miles downstream. At the new terminus, a hydro-electric power plant was constructed.27 This would, after 1907, generate power for the City of Chicago as well as the Sanitary District. The Sanitary District was slow to adopt the hydro-electric possibilities available because of the diversion. In Joliet and Marseilles, two inter-urban electric firms had by 1902 built dams and hydro-electric plants for their use. However, neither of them are now operating, while the Sanitary District’s plant is. The possibility of constructing hydro-electric plants on the Des Plaines and Illinois Rivers became a major concern. In 1911 Governor Deener informed the special session of the General Assembly, called to authorize the construction of a deep waterway from Lockport to the Mississippi, that the construction of a new hydro-electric plant on the waterway would generate 2.5 million dollars annually, which could easily pay off the 20 million dollar cost of the project. 28