Four years after California’s largest dam removal project, Steelhead trout numbers are growing, a model for other projects nationwide

by Paul Roger Read full Mercury News article here

The destruction of the [10-story] San Clemente Dam [along the Carmel River near Monterey], which had blocked the river since 1921, remains the largest dam removal project in California history. It’s still early, but one of the main goals of the project seems to be on track: The river is becoming wilder, and struggling fish populations are rebounding.

…. The 106 foot-tall dam had been located 18 miles up river from Monterey Bay. In 2016, the first year after it was removed, researchers found that no steelhead trout, an iconic type of rainbow trout listed as threatened under the Endangered Species Act, swam past its former site to a tagging location seven miles upriver. By 2017, seven steelhead had made the trip. Last year, the count was 29. So far this year, 123 steelhead have traveled upriver.

… The broader lesson, scientists say, is one of hope. Despite declines in other species, some wildlife species — from the Great Plains bison to Pacific gray whales to bald eagles — have rebounded significantly, despite plummeting close to extinction, after humans recognized what was killing them and corrected it. For bison and whales, it was hunting. For bald eagles, it was the now-banned chemical DDT. For steelhead trout, dams built across the West over the past century blocked their ability to swim to the ocean and return upriver to spawn, crashing their populations….

… Crews recycled the dam’s steel. They broke the concrete pieces ranging in size from softballs to boulders. They buried the debris in the sediment pile and covered it with willows, sycamores and other native plants. They built rocky step-pools, each one foot higher than the previous one so the fish could migrate upriver more easily. ,,