Pomponio CreekPomponio Creek is a westward flowing stream in San Mateo County, California that originates on the western slope of the Santa Cruz Mountains and flows into the Pacific Ocean at Pomponio State Beach.HistoryPomponio Creek is named for Ponponio Lupugeyun, a resistance fighter against the California mission system who had a mountain hideout at the headwaters of Pomponio Creek.Watershed and CourseA dam forms Pomponio Reservoir is located at about upstream from the mouth.EcologyA 15 foot high bedrock waterfall located about upstream from the creek mouth is an impassible barrier for immigrating steelhead trout. In 2004, the private, nonprofit Peninsula Open Space Trust purchased conservation easements on the Arata Ranch along Pomponio Creek to protect the watershed.