The Inner Harbor Breakwater, built in 1874 and sealed in 1938 with sheet piling and
clay, as well as the eight sluice gates of Chicago Lock have been leaking water from
Lake Michigan into the Chicago River.
Project
Withdrawing water from one watershed and discharging it to another has long been
an issue in the Great Lakes region. There have been many court decrees regarding
water diversion since the early 1900's and today Illinois' diversion is limited to
3,200 cubic feet per second. A number of factors including above average precipitation,
high Lake Michigan water levels, Chicago Lock operation for navigation, and uncontrolled
leakage through structures separating the Chicago River from Lake Michigan, resulted in
Illinois exceeding the diversion limit. The project will measure, control and eliminate
this leakage via the Corps of Engineers rehabilitating the leaking lock sluice gates.
The Illinois Department of Natural Resources hired CTE (Consoer Townsend Envirodyne Engineers)
to design and supervise construction of a new watertight cutoff wall, pump station,
and four 10-foot x 10-foot sluice gates to control the most serious area of uncontrolled
leakage at the mouth of the Chicago River in the Chicago River Turning Basin. The
project also included upgrades for power, telephone service and site drainage, a
new service drive and 16 foot wide access lane for limited vehicular (authorized
law enforcement) traffic out to the former Coast Guard facility, as well as the
rehabilitation and upgrade of adjacent public access lakefront facilities for
fishing and ADA accessability.
In addition to controlling lake water leakage, the new facilities add value to the
Lakefront. The cutoff wall facilitated construction of a new 450-slip boat marina
on the south side of the wall that greatly increased revenues collected by the
Chicago Park District. The final design was consistent with the City's unified
concept of beautification and its upgrade of the entire Chicago metropolitan lakefront.
The new cutoff wall offers a panoramic view of the Chicago skyline.
Contributing to the progress of the engineering profession, a number of technological
innovations were applied in the design and construction of the new facilities. For the
first time ever, CORE-LOC precast concrete units were used as a unique baffling system.
Compared to other alternatives, this new application reduced the length of the structure
and the number of sluice gates necessary to convey the allowable discharge by 50%, and
promoted a new technique for similar projects. In addition, the use of expanding
silicon/rubber sealant and a two-component epoxy for the bolted connections at the main
wall reduced construction time and cost. Special design of the cutoff wall prevents
excessive ice build-up from affecting the old Coast Guard Station and the access road
during the harsh winter months.
This project won the 2001 Consulting Engineers Council of Illinois Engineering Excellence Honor
Award.
Elements of the project
• Cutoff Wall: 1147 foot long impervious cutoff wall. Utilities to include 4" sanitary
force main, 12" water main, gas main, electric service and telephone service.
• Pump Station: Three 13,000 gpm pumps will operate between November 1 and April 1.
• Sluice Gate Structure: Four new 10 ft. X 10 ft. sluice gates in the new cutoff wall,
to replace the existing gates on the South Basin Wall, will be enclosed in a gatehouse
10 ft. high by 17 ft. wide by 100 ft. long. The sluice gate structure (as well as the
pump station) will be operated and maintained by MWRDGC.
• Mooring Dolphins: Two circular sheet pile dolphins riverward of the cutoff wall to
provide temporary mooring for commercial navigation entering or exiting the Chicago River lock.
