Roger Castillo is a citizen naturalist who grew up in the San Jose area and has walked along portions of local rivers and creeks for the past 30 years. As a "river guardian", he observes and records the changes in the Guadalupe and other local river systems that flow to the San Francisco Bay estuaries. Director Castillo discovered the remains of "Lupe" – a young Columbian Mammoth that lived approximately 60,000 years ago – while he and his dog Jenna were on a nature walk along the Guadalupe River. He works passionately on environmental and wildlife issues in the San Jose region, and founded the Salmon and Steelhead Restoration Group, a local organization committed to "Restoration through Education". Director Castillo was appointed by the Santa Clara Board of Supervisors to the GCRCD Board of Directors in 1999. His most recent term expired in November 2018, but he has remained active in District activities as a Director Emeritus..