Friday, August 12, 2011

Friday Afternoon--Center Spillway Out

Friday was our fourth day in the water at Pawtuxet Falls. The SumCo crew has completed removal of the center spillway section, and is working back toward the south or Warwick end of the dam where work began on Tuesday. The upstream pond created by the dam is dropping, flowing over the natural bedrock falls which lay beneath the dam, and is now exposed--perhaps for the first time in 200 years. Here's a video from Friday afternoon.

It was an eventful week, obviously. Work went slowly at first due to the fact that river flows were much higher than we would have liked, due to rain over the weekend and
hydro operations upstream. By the end of the week, flows were down considerably and SumCo made great progress. We d
iscovered that the center spillway had less concrete, and more rock, than expected, which was a pleasant surprise for several reasons--since the contractor is only removing the concrete, it meant the work went faster; while the height and irregularity of the bedrock will make for an interesting natural falls once the spillway is fully out.

SumCo's approach to removing the dam was to place large steel plates against
the upstream side of it; cut notches downstream of the plates; then manipulate the plates to control the rate at which the river is allowed to reach its restored level. This photo shows one of the plates in place in the center spillway section just upstream of the work area, as the excavator removes concrete rubble that was hammered away from the concrete spillway with a 1500 pound hydraulic hammer.

There was quite a crowd on Broad Street Bridge all week, watching the work. Mostly interested neighbors and other members of the public; nearly everyone I spoke with was enthusiastic about the restoration. Project partners

showed up, too--the permitting crew from DEM, engineers from NRCS, and partners from Save The Bay and NOAA. Senator Josh Miller and Rep. Joe McNamara stopped by; both were instrumental in helping with the legislative work necessary to make the project a reality. Here's what the bridge looked like for much of the week.

Travis Sumner of SumCo Eco-Contracting was running the excavator and the construction crew all week. He and his guys are just remarkably skilled and dedicated. They worked all week in the waist- or even chest-deep water. Travis seems to be able to drive the excavator over or through anything. In skilled hands, an excavator bucket is an amazing thing--able to lift and position a two-ton sand

bag, or move a rock a couple of inches. Whether walking the machine up a slope using the hydraulic arm like a giant leg or perched at a crazy angle moving rubble, Travis was clearly in full control of the machine, and the crowd on the bridge was suitably impressed.

SumCo may continue work tomorrow, and resume again on Monday--there's a chance of rain on Sunday, so we'll see what the flows look like then.

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