Progress in Motion
It’s been a busy summer! Check out our time-lapse videos of the construction work (covering June – August 2024), including a new concrete channel that allows water from the lake to flow through the spillway construction area and downstream. We’ll be regularly sharing time-lapse videos as the project progresses.
Rehabilitating Bachman Lake Dam
Now that the spillway work is well underway, crews are making updates to the actual earthen dam as well. Crews are digging a 3 ft. wide “cutoff trench” at the bottom of the existing dam as a cost-effective measure to reinforce it. Once each 20- to 50-foot section is dug out, the trench is filled with porous materials (like sand and gravel), as well as an 8-inch drain with holes in it. Any underground water seepage that comes through the dam will flow through the more porous material and collect into the new drainage pipe. From there, it can flow out and exit downstream of the dam and into the pond below the dam.
Digital sensors will be installed to monitor how much water drains out of the trench. These improvements will help keep the earthen dam strong and stable.
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Innovate, Reuse, Recycle — Putting Creativity to Work
Using a “cutoff trench,” rather than replacing the entire dam, is a tremendously cost-effective and reliable method to reinforce the dam. It’s one of several ways that the project crew is thinking innovatively to reuse and recycle materials onsite to reduce costs.
When possible, leftover materials are being recycled for use in other parts of the construction process or to serve as project materials (instead of purchasing/ shipping them in). For instance, sand discovered under the old spillway may be used as filler for the new drainage trench underway along the base of the earthen dam.
Precision is being taken into each step of the process as well — such as placing the spillway wall’s piers tightly side-by-side without re-drilling or otherwise needing to reinforce the sides. Crews also used an innovative concrete form to create the spillway walls with a flat surface, which means the team didn’t have to chisel the wall after hardening and saved concrete (image below).
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