Flat-headed mayflies (*Maccaffertium* spp.) emerged here in late May—a…

Flat-headed mayflies (Maccaffertium spp.) emerged here in late May—a remarkable sign of clean gravel and flowing water. Within two weeks, the Muskingum swelled to nearly 3,800 cubic feet per second, a surge that scours the streambed and dislodges the larvae these insects depend o