Whooshh

A dam built for hydropower has one job: generate electricity. But in most regulatory jurisdictions, it has a second obligation too, one that engineers and operators often find harder to satisfy. Native fish need to move. They've been moving along the same river corridors for thousands of years, reaching spawning grounds, returning to the sea, and cycling nutrients back into river ecosystems. A dam blocks that movement. The question isn't whether passage is needed. It's whether what's currently providing it is actually working. Traditional fish ladders have been around since the 1800s. They're a well-understood, widely used technology. But being well-understood doesn't mean being effective. According to the National Marine Fisheries Service, many fish ladder systems in the U.S. West Coast have passage efficiencies below 70% for some salmon populations. That means in a worst-case scenario, three fish in ten don't make it past a single structure. For species al...