In 1874, Fritz Zedler built a mill on the banks of the San Marcos River and, in the custom of the day, he built a stone dam and then a wooden dam to provide water and power to the mill. A concrete dam replaced the earlier dams around 1914, and, though the mill has not been active since the 1950s, the restored Zedler Mill and the adjacent park and lake are a favorite recreational area for residents and visitors. Concerns about Zedler Mill Dam were first raised when Ottine Dam, a similar structure six miles downstream of Zedler Mill, failed. The City of Luling asked Freese and Nichols to assess the Zedler Mill dam in 2009 and selected the firm to design repairs for the dam in 2011.
Data collection during design included dive inspections of the dam’s foundation along with visual observations on the condition of the dam. The dive report revealed that the sandy clay soil foundation was undermined, the wooden support timbers were no longer in contact with the concrete dam, and underseepage was extensive below the dam. Freese and Nichols originally envisioned foundation restoration by cement grouting programs. When dive inspections revealed the timber piles were rotten and unable to provide support, a new approach was developed using micropiles to provide the needed stability forces. Freese and Nichols prepared construction documents for the dam rehabilitation and provided engineering support during construction, including onsite inspection.