Duffy Gulch Fish Passage Improvement

The project will remove a fish passage barrier on the Mendocino Railway, at MP 18.0, Duffy Gulch. The existing crossing is an 8 ft. by 8 ft. concrete box culvert that extends 38 ft. in length at 2.3% slope. The drop from the culvert outlet to the downstream pool is six feet over a 16-foot-long concrete apron sloped at 33%. The crossing fails to meet passage criteria for all species and age classes at all flows (RTA, 2012). The project will replace the crossing with a structure that meets fish passage requirements, defined by CDFW and NMFS, and that will convey the 100-year flood with associated sediment and large wood. The designs followed the guidelines and criteria outlined in the CDFW California Salmonid Stream Habitat Restoration Manual (SSHRM) Part IX and Part XII (CDFW, 2009).

This project will directly benefit CCC Coho Salmon and NC Steelhead Trout by increasing access to over two and a half miles of high-quality spawning and rearing habitat in the Noyo River Watershed. Reconnecting habitat increases the amount of spawning and rearing habitat available to salmonids and lessens vulnerability to drought, high temperatures, floods, and predation.