California pulled a concrete wall from a dead creek, and what happened to the salmon stunned biologists. The barrier had blocked the waterway for decades, leaving the stretch virtually lifeless.
For seventy years, a concrete barrier blocked Alameda Creek in California, and the water behind it was widely considered lifeless. In the fall of 2025, work crews finally removed that wall. Within days, two Chinook salmon were swimming upstream through water that had been inaccessible since before the first moon landing.The fish were not placed there by humans, and no one guided them to the creek….