Up until about 1850, Sonoma Creek was unchanged from its natural state. Adverse erosion and bank cutting were at sustainable levels and did not add enough turbidity to the creek system to discourage aquatic species. Flooding in the downstream reaches did not realize the modern frequencies since all the creek reaches could absorb more excess water from peak rainfall events. The Kenwood area existed in the form of a large marsh effectively blocked by a natural earthen dam from penetrating the course of the creek as it flows west out of Kenwood toward Glen Ellen.