Michael Shaughnessy, president of the board of the Friends of Presumpscot River, walks along what was the bottom of Dundee Pond on Aug. 20. A gate malfunction at the Dundee Dam on the Presumpscot River resulted in the drainage of Dundee Pond, a local swimming hole in Windham, The accidental drainage provided a glimpse of what the river looked like a century ago, a long stretch of falls and rapids that was essential to Indigenous people long before dams were installed.

Brianna Soukup/Staff Photographer WINDHAM — Michael Shaughnessy, walking stick in hand, ambled down the bank toward a stretch of flowing river that has been hidden under a reservoir for more than a century. He stopped to marvel at the cracks in the dirt and clay on the pond floor that had formed from exposure to summer heat, at the tree stumps left behind from 19th-century logging activity, and at the newly sprouted weeds growing in places where standing water had been not long ago. This spring, an unexpected problem with one of the many dams along the Presumpscot River led to a massive drawdown of water in the impoundment known as Dundee Pond in Windham.

Although the pond disappeared, it unearthed part of the river, and in turn, a window into history. At first, Shaughnessy, president of the board of Friends of the Presumpscot River, worried about the ecological impact of the sudden drawdown and what it meant for the town, which relies on Dundee Pond as both a gathering place and as a source of summer revenue .