Looking north on July 31, 1906, the floor of the extended channel is cleared to begin construction of the Butterfly Dam as excavation of the rock downstream of the terminal wall proceeds in the background. As rock removal proceeds, the east wall of the extended channel at right and the west wall at left will be constructed to fill the gap between the original and extended channel. (MWRD photo 3288N)

By March 15, 1907, rock excavation on the downstream side of the terminal wall is nearly complete, as shown looking down from the top of the wall facing west. Across the channel, rock excavation continues using the derrick for broken rock removal. Lockport Controlling Works buildings are in the background at right. (MWRD photo 3480N)

Looking south from the terminal wall on April 17, 1907, the south pier of the Butterfly Dam has been completed and a traveler has been erected to construct the movable leaf. The leaf center column lies on its side waiting to be set upright. The Ninth Street swing bridge appears in the background. (MWRD photo 3511N)

Looking northwest, April 26, 1907. Construction is underway on the Butterfly Dam. The south pier at left is completed, and concrete is being placed in the north pier in the right background. Between the piers, erection has begun on the movable leaf. The Lockport Controlling Works is in the background. (MWRD photo 3692)

By May 6, 1907, the Butterfly Dam center column is in place and the lower leaf truss has been assembled, shown looking down toward the southeast. The derrick in the foreground assists in leaf construction. The north pier, out of the view to the left, included a vertical shaft connected to a horizontal subsurface access tunnel from the west wall. (MWRD photo 3529N)

A month later on May 28, 1907, looking south. The north pier of the Butterfly Dam is completed and erection of the movable leaf is nearing completion. At right, a section of wall that will include the west seat for the movable leaf is under construction using a traveler. The Ninth Street swing bridge is in the background. (MWRD photo 3721)

June 18, 1907. At right, a traveler is used to mix and place concrete in constructing the canal wall. To the left of the traveler, a load of aggregate is hoisted for deposition in a materials hopper. At left, the Butterfly Dam continues under construction. The through truss spans between the upstream and downstream piers and the movable vertical leaf is in-place under the through-truss and between the piers. (MWRD photo 3739)

July 17, 1907. Erection of the Butterfly Dam leaf has been completed, as shown in this northeast facing view of the leaf’s downstream face. The horizontal through truss supporting the upper leaf pivot spans from the south pier at right to the hidden north pier. In the left background, the downstream face of the terminal wall is visible. (MWRD photo 3604N)

July 17, 1907. Steel plates riveted to the leaf framework form the upstream face of the leaf. Scaffolding mounted toward the left edge of the leaf is being used to install valves that will allow water to pass through the leaf when it is closed. A similar set of valves will be installed at the opposite end of the leaf at right. (MWRD photo 3606N)

August 6, 1907, looking southeast. A large gap has been opened in the west end of the terminal wall while the cofferdam holds back the water in the original channel. The end of the west wall, visible at right through the gap, will be extended to connect to the remaining terminal wall while the east end of the terminal wall is removed. Also visible through the gap is the Butterfly Dam north pier and horizontal through truss. (MWRD photo 3622N)

August 14, 1907. The vertical leaf of the Butterfly Dam has been completed and is shown rotated to the closed position for testing. Looking southwest, six smaller gates are used for discharge of water when the vertical leaf is closed to equalize the water level on each side of the leaf. The leaf will not open with a difference in water levels. The through-truss spanning between the upstream and downstream piers holds the upper pivot of the vertical leaf in place. (MWRD photo 3781)

In the early morning hours of August 27, 1907, a section of the cofferdam next to the east channel wall was breached, allowing water to fill the space between the cofferdam and the closed Butterfly Dam leaf. Looking north from the east half of the Butterfly Dam leaf, the top of the cofferdam is seen above the supporting fill, the east channel wall at right has been completed, and the Butterfly Dam north pier is at left. (MWRD photo 3657N)

It took less than two hours to fill the small space between the cofferdam and Butterfly Dam, and later on August 27, 1907, the valves in the Butterfly Dam were opened to let water into the much larger space between the Butterfly Dam and the powerhouse, two miles downstream. (MWRD photo 3662N)

Six days later, on September 2, 1907, the waters on each side of the Butterfly Dam were approaching equilibrium, the difference being about six feet. Looking northwest from the south pier of the Butterfly Dam, the valves in the leaf are discharging at full capacity. The Lockport Controlling Works is in the background. (MWRD photo 3689N)

May 13, 1925. The Butterfly Dam has recently undergone a thorough rehabilitation and testing in anticipation of the construction of the new state lock adjacent to the District lock downstream. The vertical leaf was operated weekly for testing since its completion in 1907, but an emergency never occurred requiring its use. Looking southeast, gouges can be observed on the side of the upstream pier, a result of being frequently bumped or scraped by passing barges. (MWRD photo 11758)

The fender wall created the forebay immediately upstream of the turbine chamber intakes at the Lockport Powerhouse. The top of its arched openings, shown on September 19, 1906, were below the canal operating water level allowing water to pass and deflecting floating debris to the 48-foot dam and sector gate to be flushed downstream. (MWRD photo 3518)

April 11, 1907. Work in the Lockport Powerhouse forebay is underway to complete the turbine bay trash racks and miter gates. The west canal wall is in the right foreground, and the fender wall with arched openings runs diagonally across the forebay. Numerous windows in the north powerhouse wall admit natural light into the generator room. (MWRD photo 3666)

May 28, 1907. The upstream lock gates are left of center in this south facing view. The short wall to the right was called the guard wall and served to guide boats into the lock against the force of water moving west into the forebay. The wall to the left and a wider Sanitary & Ship Canal indicates that space was being provided for a larger lock planned in the future. (MWRD photo 3724)

Looking east on December 26, 1906. The large pie-shaped notch in the 48-foot dam will accommodate the 48-foot sector gate. An iron casting for the sector gate hinge sits atop the concrete at right. The 12- and 49-foot dams are between the powerhouse and lock. (MWRD photo 3562)

Looking east on May 7, 1907. The 48-foot sector gate is being installed into its notch and connected to its hinge. The 12-foot sector gate will be installed into the notch in the foreground. (MWRD photo 3706)

From the downstream side looking northeast, May 7, 1907. The 48-foot sector gate is in its raised position and its installation appears complete. The 12-foot sector gate awaits installation. The space between the two gates will be filled with a concrete wall and topped with a small gate control house. The southeast end of the fender wall looms in the left background. (MWRD photo 3707)

The 48-foot and 12-foot sector gates have been installed in their respective concrete dams by May 16, 1907. The southeast end of the fender wall is at left behind the wooden falsework. Both gates were used primarily for flushing floating debris that accumulated either inside or outside the forebay on each side of the fender wall. The west wall of the lock is in the right background. (MWRD photo 3714)

December 28, 1907. Completed and in operation, both sector gates are passing floodwater since the Lockport Powerhouse turbines and generators are not yet fully operational. Overhead walkway bridges and the control house have also been completed. (MWRD photo 3841)

From the downstream end of the navigation lock looking north, May 7, 1907. The tall downstream miter gates and the shorter upstream miter gates are being installed. When completed, and for a few years afterwards, this lock was the highest lift lock in the world, a notable achievement. (MWRD photo 3708)

An inspection of the lock is being conducted by a group of visitors on August 4, 1907. The group is at the 50-foot high downstream miter gates. To the left of the men standing on the wall is a set of guard miter gates to block premature entrance and damage to the tall gates. The east end of the powerhouse and forebay wall are at left. (MWRD photo 3768)

The works of the District were a magnet for engineers and public works officials. One such visiting group began at the Lockport Controlling Works on April 6, 1907. Behind the group, the Bear Trap Dam south abutment and operating mechanism is at right and the mechanical equipment building, including the District’s first water power machinery, is at left. (MWRD photo 3656)

April 6, 1907. The group continued the tour traveling by District construction contractor railroad to the Lockport Powerhouse. On the two-mile train ride, the group observed channel excavation and construction of the Butterfly Dam, bridges, levees, and walls. (MWRD photo 3659)

Looking east on May 23, 1906. A Great Lakes Dredge and Dock Company tugboat, “Andrew H. Green,” is tending a scow docked along the east wall of the Sanitary & Ship Canal upstream of the terminal wall near Lockport. The equipment will assist in the construction of the cofferdam to isolate part of the terminal wall. The wall will be removed for connection to the canal extension. (MWRD photo 3428)

Looking west-northwest across the terminal wall, December 19, 1906. The crib wall is positioned in the canal away from the terminal wall. It and flanking embankments below the water surface contain rocks, stone, sand, and clay to create an impermeable barrier. It is already deformed by the force of water on the upstream side. Bear Trap Dam and sluice gate structures are in the background. (MWRD photo 3556)

Looking north toward the south side of the terminal wall, January 23, 1907. The bedrock is being excavated by the drill and blast method. However, blasting shock waves were affecting the cofferdam and reinforcements were necessary. The bedrock will be excavated to the full depth and width of the new channel before the terminal wall removal begins. (MWRD photo 3590)

Looking east and down, March 18, 1907, from the top of the terminal wall. Excavation of bedrock is observed at right. A pumping plant to dewater the space between the terminal wall and cofferdam is located on the east wall in center background to the left of the man standing on the wall. (MWRD photo 3647)

Nearing completion, the final step is in connecting the extension to the existing canal, August 20, 1907. The water-tight cofferdam is holding back the water in the existing canal while the original concrete terminal wall is being removed and connection of the east and west canal walls is under construction. A depth of rock indicated by the ladder remains to be removed in the next six days. (MWRD photo 3788)

Looking south from Sixteenth Street, June 5, 2017. The 2012 reconstructed east wall shows the new rockfill in the foreground buttressing the wall. On top of the wall, the new roadway covers the structural elements anchoring the new precast reinforced concrete wall panels on the canal side to the anchor foundation on the east side. (Photo by author)

October 26, 2017. Across the Sanitary & Ship Canal opposite the Lockport Controlling Works is the transition from the old east wall at left to the new east wall panels at right. Beyond the wall, the City of Lockport is building a new wastewater treatment plant and is developing a historic village and public recreation area (in the background). (Photo by author)

The reconstructed west wall of the Sanitary & Ship Canal upstream of the Lockport Powerhouse protrudes westward into the Des Plaines River to provide access to both the forebay and tailrace levels of the Lockport Powerhouse. Looking south, June 5, 2017: the old wall followed a straight line to the west end of the powerhouse. (Photo by author)

Now 110-years old, the S&S Canal extension and Lockport Powerhouse continue to perform the vital function of draining the District and generating sustainable power. Looking north on June 19, 2008, the Lockport Powerhouse in the foreground is flanked on the left by the Des Plaines River, and on the right by the 20-foot sluice gate, original small lock, and the larger lock placed in service in 1933. Obscured by trees at far right is Deep Run and the Santa Fe railroad. (MWRD_061908_1178_new)