Water level is important to dredging efficiency

During the week of March 5, the water level was the lowest I’ve ever seen it in the pond at  -12 ML (12 inches below marsh level). The following week, the week of March 12, the water level was the highest I’ve ever seen it at +7 ML. Neither condition was good for dredge fill. When you think of the volume of water that was moving in and out between these two extremes, you begin to understand why the open water gets bigger and very seldom can fill in to become marsh again on its own.

The low low water was great for allowing the recent fill in Cell 4 to dewater and consolidate, and for observing any changes in the bathymetry throughout the site. However, had we pumped mud and water into that cell, it would not have stayed but would have lifted some of the previous fill and washed it out into another area. We did disconnect the outfall and moved the hose into Cell 1 temporarily to make use of my time there.

The high high water, on the other hand, would have allowed our precious fill material to flow nearly unconfined into the marsh and out into the outer pond, to be lost to our target area. We did take the opportunity it presented to partially float the hose and outfall pontoon to take out some of the hose sections and rearrange the outfall configuration.

This sounds easy, but was physically exhausting for both of us. We used a canoe and a pirogue to get back and forth, an ATV and a lot of rope to pull the hose, and then a torch, hammers, levers and a lot of muscle to get each corroded connection apart.

The weather this week does not look conducive to dredging because of high winds and predicted thunderstorms. Isn’t March supposed to “go out like a lamb?”

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