The Mattole watershed encompasses 304 square miles within the northern California Coast Mountains, some of the most rugged and geologically active land in California. The Mattole River flows completely un-dammed for 62 miles fed by over 74 tributary streams, from northern Mendocino County to its mouth at the Pacific Ocean, 10 miles south of Cape Mendocino.
From the1940s to the 1970s, intensive timber harvest and other land use changes created hundreds of miles of poorly built roads. 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. 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.
Some of the dominant hardwood trees include California Buckeye (Aesculus californica), Oregon White Oak (Quercus garryana), several Live Oaks (Quercus spp.), Pepperwood (Umbellularia californica), Tanoak (Lithocarpus densiflorus), Madrone (Arbutus menziesii), and, in riparian areas, Red Alder (Alnus rubra), Oregon Ash (Fraxinus latifolia), Elderberry (Sambucus spp.), Bigleaf Maple (Acer macrophyllum), Vine Maple (Acer circinatum), Dogwood (Cornus spp.), and several species of Willow (Salix spp.).
While the forests of the Mattole are diverse, three species stand out in the economic history of the place: tan oak, Douglas fir, and coastal redwood. The bark of tan oak was harvested in the late 19th century for its high tannin content. Tannic acid was necessary in the process of leather making. Most if not all of the harvested material was taken out by ship, from the mouth of the river near Petrolia.
Right: Tan bark piles before export from Petrolia in 1907. Photo courtesy of the Mattole Valley Historical Society.
Riparian forests, those that grow along creeks and the River, are important to fisheries and riverine health as well. A healthy riparian canopy shades the watercourse and maintains cool water temperatures. In many coastal rivers, summertime water temperatures approach levels high enough to be lethal to salmonid fishes. Riparian zones act as a "buffer" between upslope lands and the river. This can work to prevent excessive nutrients and sediment from entering watercourses. Riparian vegetation also "armors" stream banks so that they can withstand high stream flows lessening the chance of eroding the banks. Fallen riparian vegetation (particularly the larger and more rot-resistant conifers) also contribute large woody debris to the river, which is important in the creation of complex habitats preferred by young salmonids.
From the time of the migration of Eastern settlers to the watershed, land in the Mattole was held in large tracts primarily for ranching and orchard agriculture. The standing-timber tax forced much of the ranching community to either log their land or lose it. In 1957,
In 1988, the Mattole Restoration Council created a map depicting the ancient forest cover in 1942 and in 1988. Below is a picture depicting old growth forests as of 1997, which shows that of the total Mattole forestlands, only about 9% remain as ancient forest. That percentage has since dropped to less than 8%. The MRC is actively engaged in efforts to preserve remaining old growth forests.
The Mattole watershed is located in one of the most geologically active spots in North America. Three tectonic plates meet offshore, the North American, the Gorda, and the Pacific, forming the Mendocino Triple Junction. This network of faults produces many earthquakes, including the large and devastating events of 1952 and 1992. To learn about recent earthquakes in the area, click here.
Rates of uplift in the King Range are among the highest anywhere in North America.
The Mattole watershed is underlain primarily by young sedimentary rocks, which are highly erodible and often incompetent - easily fragmented and cracked. Soils, which are primarily of the Atwell, Boomer, Cahto, Hugo, Josephine, Kneeland, Laughlin, Los Gatos, Mattole, Maymen, McMahon, Melbourne, Usal, Wilder and Zanone series, range in depth from less than a foot on rockier ridge tops to more than six feet in bottomlands.
Before Europeans arrived in
Perennial grass species exist in patches in the Mattole, but have been largely supplanted by introduced annual grasses from
Research suggests that grasslands historically covered around 25% of the Mattole watershed. These grasslands are important economically, particularly for cattle and sheep ranching, and other agricultural operations.
Last year, the Mattole Restoration Council completed a project comparing the extent of grasslands in 1950 and 1998. According to this research, more than a third of the Mattole's grassland's have disappeared since 1950, primarily due to fire suppression which allows fir and brush to encroach on the prairie edges. To see the full report, look at centerfold of Newsletter #19.