The Laguna de Santa Rosa is Sonoma County's richest area of wildlife habitat, and the most biologically diverse region of Sonoma County (itself the second-most biologically diverse county in California)... It is a unique ecological system covering more than 30000 acres and a mosaic of creeks, open water, perennial marshes, seasonal wetlands, riparian forests, oak woodlands, and grasslands... As the receiving water of a watershed where most of the county's human population lives, it is a landscape feature of critical importance to Sonoma County's water quality, flood control, and biodiversity.