Chicago Sanitary & Ship Canal [CSSC]
The Chicago Sanitary & Ship Canal [CSSC] is a manmade channel that was constructed in 1900 to supplement and ultimately replace the Illinois and Michigan Canal as a conduit to the Mississippi River system. Its construction facilitated the reversal of the Chicago River.
Historically, the Chicago River was a very important factor in the development of the City of Chicago, as it was part of an easy portage route for canoers between the Great Lakes and Mississippi River systems. The discharge of open sewers into the river and Lake Michigan led to severe health problems for city residents. To correct this problem, the entire city was raised 10 ft in elevation to improve sewer drainage to the river. This system of combined intercepting sewers discharging to the Chicago River was built, and the flow of the river was changed by construction of the CSSC.
The Canal proper is 160 feet wide in the solid rock, extending over 15 miles. Through the earth and hard pan its length is 13.1 miles, varying in width all the way from 198 to 290 feet at the water edge; having a universal depth throughout its entire length of the approximate twenty-eight miles of not less than twenty-two feet of water. As to the size of the Chicago Canal, it can be stated that it ranks in size with the largest canals of the world, and it has a greater cross-section than either the Suez, the Manchester or the Baltic Ship Canal. The Canal of 28 miles is exclusive of the Chicago River proper. The Canal is spanned by the finest and the most modern movable type of bridges that ingenuity could devise, having thereby given full consideration to the navigable feature of the Canal.
The continual or persistent connection between the Great Lakes Basin and the Illinois River was established in 1848 with the completion of the Illinois and Michigan (I&M) Canal. The dimensions of the original I&M Canal were 60 ft wide at the surface, 36 ft wide at the base, and 6 ft deep. In the spring of 1849, the LCR was connected to the I&M Canal via the 40 ft wide and 4 ft deep Calumet Feeder Canal, which had been constructed through the Saganashkee Slough. The I&M Canal was replaced by the much larger CSSC, started in 1892, that connected Lake Michigan with the Illinois Waterway. The permanent connection between the Lake Michigan and the Mississippi drainage was finalized with the completion of the CSSC in 1900.
Earth was first broken on "Shovel Day" - Sept. 3. 1892, on the rock cut below Letuont. About 13 miles of new river channel had to be excavated with the location of the Main Drainage Channel, and about 19 miles of levee built to divorce the witers of the Desplaines watershed fro'n the channel which Is to receive the waters of Lake Michigan and pass them on to the Mississippi River via the lower Desplaines and the Illinois rivers.
The fluctuations In Lake Michigan, by varying slope of water surface, will be felt at the controlling works, and provisions must be made to meet these fluctuations within a range of 5 ft. above datum and 8 ft. below, or an extreme oscillation of 13 ft. The fall from datum at the controlling works to the level of the upper basin was about 42 ft.
At the time, the Suez canal had a bottom width of 72 feet, just sufficient for one large steamer. It was in fact a "single-track" canal with "turnouts "; the Chicago canal was "double track." The Suez canal had a top width of 197 feet, the depth in center being 26 feet or 7 feet more than that of the Chicago canal. The Amsterdam ship canal had a bottom width of 89 feet, top width of 197 feet and depth of 23 feet, or 4 feet more than that of the Chicago canal, but it was also a onehorse canal.
The superior dimensions of the Chicago canal were not so much demanded in the interests of navigation as in those of sewage disposal, the law demanding as it did a water supply for diluting Chicago's present and future excreta to the enormous amount of 600,000 cubic feet per minute.
With regard to the difficulties, the first is the lowering of the lakes by the abstraction of so large a volume of water. This matter received very close study, and the result has been to show that no positive detriment would result to the navigation of the Detroit river or any other of the points where deep water is hard to get. In the second place, the addition of so large a volume of water to the Illinois river would doubtless affect the low-lying lands of the Illinois basin to some extent. Many of the farmers were crying out against the Government for having dammed the river in several places, rendering their lands water-logged.
The Calumet River was dredged to a depth of 16 ft; between 1911 and 1922, the Calumet Feeder Canal was obliterated by the construction of the CSC, which was incised through a vast and unique dolomite prairie, formerly the Saganashkee marshland. With the completion of joining the CSC with the Calumet River, the Calumet region’s drainage was chiefly reversed; and in 1965, the Calumet River was completely reversed by the construction of the T.J. O’Brien Lock and Dam near the original confluence with Lake Michigan.
Industrial and commercial land use dominates the riparian zone along most of the CSSC. There is little to no canopy cover and instream habitat for aquatic life is limited. Silt and sludge makes up a majority of the sediment at Damen Avenue, with depth of fines ranging from 1 to 9 ft. At Cicero Avenue, deposited sediments are 1 to 4 ft deep and are composed of mostly silt and sludge. Sediment, composed of mostly silt, was slightly more variable at Harlem Avenue, but there was also sand, gravel, cobble, and boulders near the bridge. The bedrock was exposed due to scouring near Route 83 and Stephen Street, with some scattered silt deposits. Areas of scouring, as well as pockets of deep silty sediments also occur near Lockport, although habitat improves slightly near the sunken barges on the west bank. Aquatic vegetation and snags are present in this shallow area with deep sand and silt deposits . Water and sediment quality is impaired throughout.
Portions of the Chicago River and the CSSC were constructed in the native dolomite limestone. Accordingly, aquatic habitat within the canal is quite poor and fairly homogeneous, consisting of vertical limestone walls that extend 24 to 26 ft down to the bottom. These nearly perpendicular walls of the canal offer little or no littoral zone habitat for aquatic species. The walls have crumbled down enough at various locations along the reach and may now provide limited littoral habitat for present species. The bottom of the canal is very flat with limited fine substrates; however, rock or flagstone is present on the bottom of the canal. There are also intermittent areas of woody debris and detritus that may be used as cover for certain benthic organisms.
The Lockport Lock and Dam consist of one lock chamber, a dam and powerhouse, and an abandoned lock. The MWRDGC uses the dam to control the outflow of the CSSC and limit the diversion of water from Lake Michigan into the Des Plaines River. The Lockport Powerhouse was built in 1900 and consists of two units of turbines and generators, nine pit gates, and a lock. During normal operation, one turbine usually runs to pass dry weather flow downstream and maintain a water depth adequate for navigation from the lakefront to Lockport. The nominal lift between the Lockport Pool and the Brandon Road Pool equals approximately 39 feet.
Located downstream of the CSSC on the Des Plaines River, the Brandon Road Lock and Dam contains one lock chamber and a dam. This dam contains 8 operational headgates and 21 tainter gates. The nominal lift between the Brandon Road Pool and the Dresden Island Pool equals approximately 34 feet.
Problems have arisen in the past when moderate to severe rainstorms have exceeded the capacity of the combined sewers and sewage treatment plants. This forces the sewage to be discharged into the Chicago River. If this overflow discharge is only moderate, the flow may still continue down the CSSC to the Illinois River. However, on occasions when this inflow volume is so great that Chicago River stages threaten to overflow the river banks, the sluice gates and lock on Lake Michigan at the original mouth of the River are opened to permit backflow to the Lake to prevent city floods.
There is also a lock and dam downstream on the CSSC at Lockport, Illinois, that affects upstream stages and flow patterns of the entire CAWS. When heavy rains are forecasted, pit gates in the Lockport powerhouse are opened to draw down the CAWS prior to the storm to maximize flow capacity. This procedure is always at least partially successful, but sometimes not enough to prevent backflows into Lake Michigan.
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