Portions of the Eau Pleine Dam were constructed in the 1930s, and after decades of service, the dam no longer met Federal Energy Regulatory Commission minimum safety standards. The dam, owned and operated by the Wisconsin Valley Improvement Company, forms the Eau Pleine Reservoir on the Eau Pleine River.
Ayres worked with the company to improve the dam, including raising embankments by 2 feet, stabilizing the upstream and downstream slopes, and constructing an auxiliary spillway. Ayres was retained to:
- Perform a seepage analysis of the existing embankment.
- Compute slope stability factors of safety for the proposed embankment configuration.
- Design a sloping drain to safely convey seepage from the embankment. This drain was designed using NRCS standards outlined in the National Engineering Handbook – Part 633 Soil Engineering – Chapter 26 – Gradation Design of Sand and Gravel Filters. The U.S. Army Corps of Engineers EM-1110-2-1901 – Seepage Analysis and Control for Dams was also consulted for the drain fill design.
- Prepare construction drawings, specifications, design reports, quality control and inspection programs, and construction documentation reports.
- Attend the FERC/BOC meeting to present and discuss the pre-final and final design.
- Provide on-site construction supervision.
- Provide on-site technical assistance during construction.