The Aluminum Dam

One of the Senior Design projects our students in the Civil Engineering Department at Pitt implemented this term was an extensive study of the feasibility of reversing the tendency of Canonsburg Lake to slowly transition from a healthy body of water into a permanent wetland.

I distinctly remember when “the aluminum dam” was constructed, forming what is now known as Canonsburg Lake. I remember my father taking my brother and me there fishing in its earlier days. I remember going to plays at the Little Lake Theater in the 1960s. My curiosity made it easy for me to decide to research the rationale for its original construction.

The story actually begins in 1903 when a group of Canonsburg businessmen formed the Standard Tin Plate Company to produce thin gage steel sheets, plated with tin, for supply to companies producing tin cans. They also developed a subdivision nearby to house the workers. The plant was an instant success and soon became “one of the finest tin plate mills in the country.”

Seven years later the Continental Can Company announced its plans to build a large tin can factory adjacent to the tin plate mill and its intention to acquire all the assets of Standard Tin Plate. Included in the agreement was a commitment for supply of all the tin plate needed by the can company for ten years. The combination was extremely successful, providing Canonsburg with prosperity for the next thirty years, while employing several thousand workers.

The prosperity was compromised in 1941 when Carnegie-Illinois Steel Company, the supplier of “black steel” to Standard Tin Plate, purchased the mill from Continental Can. A year later they announced that the tin plate mill was being shut down, a casualty of World War II. A group of Canonsburg officials appealed this decision to a special Senate committee investigating the war production program. Senator Harry S. Truman was chairman of the committee.

The Carnegie-Illinois officials reported that the War Production Board’s restrictions on tin had made it impractical to continue operations in Canonsburg. Chairman Truman questioned Carnegie-Illinois’ motivation for purchasing Standard Tin Plate, implying it was to acquire the orders of Continental Can. Despite reporting sympathy for the Canonsburg community, the committee concluded there was nothing to be done to prevent the closing.

Things turned for the better later in 1942 when the Defense Plant Corporation announced the facility would be repurposed as an aluminum forging facility to be operated by the Aluminum Company of American (ALCOA). Its product would be components for aircraft being constructed as part of the war effort. Canonsburg’s continued industrial prosperity had been salvaged.

A dependable supply of water was required for operations of the forging plant; to achieve this, Little Chartiers Creek was dammed a short distance above its confluence with Chartiers Creek, producing a seventy-six acre lake. The concrete dam is forty-five feet high and five hundred and twenty-five feet long. The resulting lake is five hundred feet wide at its maximum and snakes nearly a mile in the shape of a fish-hook.

When the war ended, the forging plant was closed and again Canonsburg was faced with an economic crisis. This time the rescuer was the Pennsylvania Transformer Company, which moved into the idle facility in 1946, and has been a major employer in the community ever since.

In 1957 ALCOA transferred the 138 acre property that included the lake, the dam, and surrounding lands to the Pennsylvania Fish and Boat Commission (PFBC), confirming the conversion of an industrial reservoir into a recreational asset. Canonsburg Lake became a popular site for outdoor enthusiasts, including fishermen, boaters, and bird-watchers. Boating was restricted to canoes, kayaks, and boats powered by electric motors.

Little Chartiers Creek is about twelve miles long, beginning south of I-70 near Glyde and flowing due north to the lake. Its watershed covers forty-six square miles, about half of which is agricultural. Erosion introduces fine-grained soil into the creek during heavy storm events.

With time the lake began to fill up with silt, especially upstream from the embankment and bridge carrying McDowell Lane across it. A non-profit organization, the Canonsburg Lake Restoration & Improvement Association (CLRI), was formed to raise funds to restore and improve the lake.

In 2012 three million dollars was spent to “stabilize” the dam and remove it from the PFBC list of “deficient” structures. Two years later a weir was installed on Little Chartiers Creek to catch upstream sediment and debris. Dredging silt from the lake, dewatering it, and disposing of it is still in the future.

The project our students implemented suggested that it was feasible to remove about 100,000 cubic yards of silt, process it, and dispose of it. Their estimated cost is about fifteen million dollars. They believe that failing to do this will eventually result in about half of the lake becoming a wetland, too shallow for boating.

It will be interesting to see how this situation plays out. Who determines the value of a 73-acre recreational lake in the middle of a heavily populated area that is still growing? We certainly hope that society at some level will decide that preserving Canonsburg Lake is a high priority initiative.

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