Delnor Dam was originally constructed in the 1930s on private property to impound water for the creation of a pond. At 131 feet long by 7 feet high, the dam was designed and installed without engineering software, laser levels or chemically-based epoxy. Thus, the soundness and longevity of the workmanship is admirable.
When you think about all the progress, development and change this area has received since then – roads, storm water systems, large neighborhoods built to the north, 100 year floods – this dam has been doing its job for 85+ years. A quite impressive achievement!
In 1998, the Park District purchased 23 acres from the Norris Estate and officially opened the area as a public park in 2000. Ultimately, the dam began to structurally deteriorate and fail to function properly in 2011. To preserve this historic feature, the Park District sought assistance from local engineers and regulatory agencies through a bid process.
First contractors created a coffer dam that allowed them to stop the water around the existing dam to begin the repairs. Then parts of the old structure that had failed were removed, new flowable fill concrete was poured in three tiers and a stacked limestone façade was installed. Once again, the dam is fully functional for visitors to continue enjoying fishing and bird watching.