Chicago Sanitary and Ship Canal at Romeoville, IL




Study Reach.--The channel reach is an excavated channel through a rock outcrop. The study reach, as shown in the satellite map (taken from Google map) on the top left, is about 5.9 miles long on the Chicago Sanitary and Ship Canal (CSSC). The study reach is defined by two USGS streamflow gaging stations. At the upstream end of the reach, the USGS streamflow gage at Lemont is located 1.5 mile upstream from the Lemont Road bridge and at the downstream end of the reach the USGS streamflow gaging station at Romeoville Road is located at the East Romeoville Road bridge. Twenty-one cross sections surveyed by the USGS in July 2007 are available for describing the channel geometries in the study reach. A terrain map (also taken from Google map) on the top right illustrates the approximate variations in channel width and locations of these cross sections. Because most cross sections have similar geometries, cross sectional plots for river stations (RS) 2, 10, 15, and 18, as plotted above, are selected as representative cross sections.

Gage Location.--The downstream Romeoville gage, USGS streamflow gaging station number 05536995, is located at Lat 41°38'27", long 88°03'34" (NAD of 1983), in SE1/4 SW1/4 sec.35, T.37N., R.1 E., Will County, Hydrologic Unit 07120004, on the left bank 40 ft upstream from the bridge on East Romeoville Road (135th Street) in Romeoville, 5.2 mi upstream from the Lockport Lock and Dam, and at river mile 6.2 of CSSC (Illinois Waterway mile 296.2). The upstream Lemont gage, USGS streamflow gaging station number 05536890, was established in March 2004, to replace discharge measurements at Romeoville. The gage location is at Lat 41°41'29", long 87°57'52" (NAD of 1983), at CSSC river mile 12.0, and Illinois Waterway river mile 302.0.

Drainage Area.--739 sq mi.

Gage Datum and Elevations of Reference Points.--Datum of the Lemont gage is 551.76 ft above NAVD88. RP-1 is two file marks in an aluminum angle bolted to the wall on the right bank located 1.5 mi upstream from the Lemont Rd. bridge, elevation = 584.15 ft. A staff gage is located 5.9 mi downstream at Romeoville, elevation of bolt on the staff = 581.64 ft. All elevations are referenced to NAVD88. The Romeoville gage was discontinued and all equipment removed on May 10, 2006.

Stage, Discharge Measurements and Computed n-Values.--Discharge measurements are made with an Acoustic Doppler Current Profiler (ADCP) by boat near the Lemont gage or downstream near the Romeoville gage. To minimize the backwater effects from the Lockport Lock and Dam, data for the n-value study were selected from ADCP measurements taken during the period when the gates at Lockport were all open and that both the Lemont gage and the Romeoville gage were in operation. Water-surface slope for each selected event was determined by taking the difference in water surface elevations between the Lemont and Romeoville gages at the time of discharge measurement and dividing by the distance. The computed n-values are listed in the following table.

Date of Observation Discharge (ft3/s) Average Cross Section Area (ft2) Hydraulic Radius (ft) Mean Velocity (ft/s) Slope (ft/ft) Coefficient of Roughness n
1/14/2005 10771.0 3599.0 18.42 3.05 0.000070 0.029
1/14/2005 12133.0 3585.0 18.36 3.44 0.000089 0.029
1/12/2005 13130.0 3426.0 17.74 3.90 0.000118 0.029
1/13/2005 14657.0 3668.0 18.68 4.06 0.000127 0.030


Description of Channel.--The reach is mostly straight with a mild southern bend near Romeoville. Cross sections are generally rectangular in shape. The canal was constructed by using dynamite to cut an opening in the limestone outcrop. Bed materials consist of bedrock and coarse gravel. Bank material is limestone bedrock. The banks are near vertical walls approximately 30 feet high with top widths varying approximately between 140 feet and 180 feet.

Floods.--Maximum discharge, 19,466 ft3/s, Feb. 21, 1997, gage height. 23.95 ft.

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Page Last Modified: February 4, 2013