In 2017, California replaced a fish-blocking road crossing on Upper Green Valley Creek; surveys later found 136 young steelhead upstream of the former barrier

In 2017, engineers undertook a significant project to replace an old culvert that hindered fish migration in Upper Green Valley Creek. The successful replacement is evidenced by the discovery of 136 young steelhead fish in previously unreachable habitats. Researchers are actively studying the long-term effects on these fish populations and their growth.