spelling Putas occurs. In the Statutes of the early 1850s, in the Indian Reports, and in the Pac. R.R. Reports, the spelling of the name is in complete confusion. The present version was applied to a town in 1853, was used in the Statutes of 1854, was made popular by the Bancroft maps, and finally was adopted by the USGS. According to a map created by Eugène Duflot de Mofras, a French naturalist and explorer, and published in Paris in 1844, Putah Creek was once known as Young's River, named for the fur trapper Ewing Young, who hunted beaver on an expedition up Putah Creek to Clear Lake and on to the Mendocino County Coast in March, 1833. The lower reaches of the creek used to sometimes be called Walnut Bayou, in reference to the warm and sluggish water and the abundance of California Black Walnut trees on the banks. Watershed and course The creek originates from springs on the east side of Cobb Mountain south of the town of Cobb in southwestern Lake County and flows approximately to Lake Berryessa. It descends eastward to the town of Whispering Pines, where it turns southeast, parallelling State Route 175. It passes the town of Anderson Springs, where it joins Bear Canyon Creek. North of Middletown, it curves counterclockwise around Harbin Mountain, merging in close succession with Dry Creek, Helena Creek, Crazy Creek, Harbin Creek, and Big Canyon Creek. From Harbin Mountain, it flows east again, joining Bucksnort Creek, then enters Napa County at a confluence with Hunting Creek about east of Middletown. In Napa County, the creek flows southeast, merging with Butts Creek just before it empties into Lake Berryessa, and the Monticello Dam. Downstream of Monticello Dam, on the southeastern corner of the lake, Putah Creek leaves Napa County and becomes the boundary between Yolo County and Solano County flowing about to the Putah Diversion Dam (PDD), where most of water flows are diverted south through the Putah South Canal to users in Solano County. In this section the creek offers excellent fishing opportunities year round. California Department of Fish and Wildlife regulations require "catch and release" in this section of the stream, as well as the use of artificial lures with barbless hooks. The California Office of Environmental Health Hazard Assessment (OEHHA) has developed a safe eating advisory for fish caught in Putah Creek based on levels of mercury