The Van Duzen River Basin drains approximately 430 square miles of mountainous terrain in California’s North Coast Range (Figure 1). Eighty-four percent of the basin is within Humboldt County and the remaining portion (16%) is within Trinity County. The Van Duzen River is a major tributary to the Eel River which flows into the Pacific Ocean approximately 15 miles south of Eureka, in Humboldt County. Elevations in the Van Duzen River Basin range from approximately 5,900 feet at the upper basin headwater peaks (Mount Lassic, Black Lassic, and Red Lassic) to a low elevation of 60 feet where the Van Duzen joins the Eel River near the town of Fortuna, and approximately 13 miles from the Pacific Ocean.