THE PULSE • Nov 1, 2026
A trap waits at the end of a pipe on a small stream in Maine. Water rushes through it toward a spinning wheel of metal. Somewhere inside, a handful of silvery fish no longer than a finger are about to find out if they survive the trip. For decades the answer at dams like this one was grim. At Freedom Falls, a small hydro plant, something different happened. What changed inside that spinning wheel is the whole story. A turbine maker bulit a runner with fewer, thicker blades, rounded leading edges and a forward slant running from the hub out to the blade tip. The clearance around those blades matters. The setting for the real test was Freedom Falls, a 35 kilowatt hydropower project at a refurbished historical mill dam on Sandy Stream in Maine. The pooled immediate survival estimate was 98.2 percent, and the pooled 48 hour estimate was 100 percent.