Wahpeton Slurry Trench
- Location North Dakota
MethodsTrench excavation, Precise mixing of materials, Slurry trench construction
Michels constructed a 1,200-foot slurry trench near a riverward toe of a levee. The slurry trench varied in depth from 22 to 25 feet. The trench was needed to address concerns that high water pressure on one side of the levee coupled with groundwater traveling under it would compromise the integrity of the levee. Michels used an extended-reach hydraulic excavator to dig the trench. A mixing pit was set-up nearby. Trucks hauled the spoils to the mixing pit where an excavator and bulldozer were used to mix and fold tightly controlled percentages of water, bentonite and existing soil. This created an impervious backfill of material. The backfill then was hauled back and placed into the trench to create a pliable and waterproof barrier through which groundwater could no longer migrate. Laboratory tests confirmed Michels' completed work far exceeded project requirements.