 The Yulupa Creek watershed comprises an area of approximately five square miles, and is considered a viable steelhead, "Oncorhynchus mykiss", spawning habitat; stream surveys conducted from 1966 to 1986 indicated significant, but declining populations of anadromous fish.NOAA fisheries has designated the Yulupa Creek watershed as "Critical Habitat" for "Oncorhychus mykiss" as well as "O. tshawytscha" (Chinook Salmon) as of 2004.Land use in this watershed consists of Annadel State Park usage and very low density rural single family residential development, much of which is upmarket housing stock.