The River Fights Back: Coffer Dam Breach

On November 1st, the river collected on October's warning shot. The coffer dam suffered its first major breach, and the entire worksite flooded.

Nobody was hurt — the site is planned around exactly this possibility, and no one works downstream of retained water without an exit plan. But the damage to the work itself was real: the dry work area we've depended on since August went underwater, taking weeks of site preparation with it and depositing a thick layer of silt and debris over everything.

There's no way to dress this up as anything but a setback. Re-shoring the site and cleaning out the debris took over two weeks — two weeks spent recovering ground we'd already won, with the New England work season burning down around us.

But this is what working in a river is. A coffer dam is a temporary structure asked to hold back a live watershed through whatever the sky delivers, and fall in New Hampshire delivers. Every coffer dam that has ever been built has been in a negotiation with the river, and the river renegotiates after every storm.

The work area is dry again, the shoring is stronger than before, and we're pushing to get as much done as the remaining season allows. December in a river valley is coming fast, and at some point the smart move is to stop fighting the water and let winter have the site. We're not there yet — but we can see it from here.