As the result of a regulatory inspection, a Midwest utility was required to install two emergency spillways in existing CCR basins. The project included the reinforcement of existing spillways, site grading, road improvements, and modifications to process piping systems.
“Trans Ash was able to work with both the client and the design engineer to finalize the design concurrently with construction.”
Project Challenges & Solutions
Several items were encountered throughout the life cycle of this project that created the following challenges:
- Due to the regulatory time frame, the project was required to be completed during the winter season, leading to the possibility of weather delays. To mitigate this challenge, additional equipment was mobilized to ensure proper compaction of material, and the work schedule was adjusted to include additional hours when the weather was favorable.
- The CCR basins remained in operation during the installation of the emergency spillways. This created the challenge of excavating the spillway, while retaining water within the basin. To mitigate this, the basins were drawn down as much as possible to allow excavation while still keeping them in operation. Additionally, coffer dams were deployed in areas where the draw down was insufficient to allow for the scope of work.
- The design called for the installation of aggregate below the water level in the basin where a draw down or use of a coffer dam was not possible. This challenge was overcome through the use of GPS excavators with waterproof components. Trans Ash was able to install the aggregate below the water level, both safely and within design tolerances.
- Due to the expedited schedule, the design was completed concurrently with the installation. Trans Ash worked jointly with the design engineer to complete the design and create suitable installation methods.