Photo: Amanda Malachesky

The Mattole River originates in northern Mendocino County, and flows in a northwesterly direction until it nears the town of Petrolia, where it takes a notable turn and meanders through a broad east-west trending valley. It enters the Pacific Ocean 10 miles south of Cape Mendocino, the western most point in California.

The main stem of the Mattole is approximately 65 miles (100 km) long, and drains a watershed area of approximately 304 square miles, fed by over 74 tributary streams. The river and its tributaries provide important habitat for three salmonid fish species: steelhead trout, Coho (silver) salmon and Chinook (king) salmon. Click here for a list of websites about salmon.

River systems are dynamic - they are the link between erosion of upslope lands, the creation of alluvial floodplains, transport of eroded materials to the ocean, and habitats for aquatic organisms. Rivers inherently transport sediment, much of which will eventually turn into beach sand. It is this sediment that plays an important role in determining the geomorphology of the river (i.e. its shape, response to flooding, sinuosity, and habitat characteristics).

The Mattole River, in this extremely geologically active and unstable watershed, is choked with sediment, which reduces its capacity to support fish and other aquatic organisms. Before widescale timber harvesting, erosion happened slowly over thousands of years, and the river could transport sediment at a rate roughly equal to input of new sediment. From the1940s to the 1970s, intensive timber harvest and other land use changes created hundreds of miles of poorly built-and later abandoned-roads, and hillsides denuded of the vegetation holding the soil in place. Combined with the floods of 1955 and 1964, many deep pools that used to exist in the river filled in, and the river channel became flatter and wider.

These changes have redefined the geomorphology of the river, and there is little we can do to bring the river back to its narrower and deeper conditions other than to help prevent sediment inputs and wait for the river to flush itself out. In response, the Council initiated the Good Roads, Clear Creeks Program in 2001 to assist landowners with sediment reduction. Based on the recommendations in the Council's 1989 report "Elements of Recovery," this is our primary strategy for assisting the river return to its pre-timber harvest condition.