Mattole River

River in the United States of America

The river and its 74 tributaries drain about 304 square miles (787 km2), including the eastern side of the King Range, and flows through Mattole Valley before emptying into the Pacific Ocean. Although the Mattole River's source is at about 1780 feet (543 m) elevation, its tributaries originate as high as 4000 feet (1219 m) above sea level. The North Fork of the Mattole River enters the river main stem just west of Petrolia. For most of its length, the river is only a 4.2 mile (7 km) east of the King Range National Conservation Area. About halfway to the ocean, near Honeydew, California, the river passes by Humboldt Redwoods State Park. There are numerous tributaries and creeks that feed the drainage area. Some of the largest are the Upper North Fork at Honeydew (as opposed to the North Fork at Petrolia), Honeydew, Bear, Rattlesnake, and Oil Creeks.

The Mattole River has been declared by the California Coastal Commission as a 303(d) impaired waterbody that flows into a Marine Protected Area (Punta Gorda State Marine Reserve). Areas in the Mattole River watershed are being restored to revive habitat that was degraded by a combination of early industrial style timber harvest techniques and associated road construction, naturally erosive geology, and damage by two 100 year floods, which occurred in 1955 and 1964. The Mattole River and Range Partnership, consisting of the Mattole Restoration Council, Mattole Salmon Group, and Sanctuary Forest, undertakes this work with the collaboration of watershed landowners and funding from multiple private and sources. The river is used for recreation and agricultural, municipal and industrial water supply. It also provides wildlife habitat, including cold freshwater habitat for fish migration and spawning. The Mattole River is home to three salmonid species listed as threatened under the Federal Endangered Species Act: chinook and coho salmon, and steelhead. Coho salmon are additionally listed as threatened under the California State Endangered Species Act. The Mattole Salmon Group counted just three adult Coho salmon in the river in the 2009 2010 winter (and only one redd), which is the lowest number of coho counted since the group began surveys in 2004. This is far below the 19th century historical estimates of 17,000 to 20,000 adults annually, or the 1950s and 1960s estimates of 8,000 and 5,000 annually, respectively. In 2010–2011 ten coho were counted and five redds, but these numbers are 95% lower than 2006–2007. Each salmon run is on a three year cycle. The Mattole Restoration Council, the Mattole Salmon Group, Sanctuary Forest, the Mill Creek Watershed Conservancy, the Upper Mattole River and Forest Cooperative and the Mattole River and Range Partnership fosters the Mattole River habitat restoration work and serves as a model for other communities wanting to work cooperatively to repair anadromous salmonid habitat. Recently the group planned a pilot project to decrease winter runoff and increase summer flows, by using a model of beaver dams and pools. Research done by an ecosystem analyst from the Northwest Fisheries Science Center of NOAA Fisheries shows that salmon smolt production per beaver dam ranges from 527 to 1,174 fish, whereas production in a pool formed by large woody debris is only 6 to 15 fish. This suggests that re establishment of beaver populations would be 80 times more effective in salmonid recovery efforts than placement along of large woody debris. In the early 1990s residents of the lower Mattole River (Humboldt County, CA) watershed created the Mattole Watershed Alliance to work on improving Mattole River conditions toward the common goal of preserving populations of wild salmonids. The common plant associations within the Mattole include the following: (1) coast redwood forest (in the southern headwaters), (2) mixed coast Douglas fir and hardwood primarily tanoak and Pacific madrone forest, (3) mixed chaparral, primarily manzanita, mountain whitethorn, California scrub oak, and coyote brush, and (4) grasslands. Riparian zones of the Mattole also support bigleaf maple, red alder, Fremont cottonwood, Oregon ash, and willow.

Arthur W. Way County Memorial Park is on the north bank of and adjacent to the river.

In the 1850s, Euro American settlers started ranching and agricultural traditions on the land. This would inhibit contraction of disease and decrease the native Mattole tradition of relying on river resources. Post World War II: Logging of Douglas fir became an increased practice for this period of building construction and the tax value of standing trees rose as well. The MSG created gravel lined "hatchboxes" to substitute for the lost spawning habitat areas. Adult spawners were held until they had their eggs and these were incubated in the hatchboxes. This process jumped the survival rate of "egg to fry" from 15 percent to 80 percent. They began incubating salmon eggs, clearing logjams and obstacles for fish migration and plant trees to sustain the riverbanks. They will choose to take care of the salmon before they work on their homesteads. In 1997, timber harvesting limited the ancient pacific tailed frogs in the headwater channels causing the species became endangered. In 2005, the pacific tailed frogs could be found in small population sizes along old growth forests. Their small populations are scattered along the river, because of heightened water temperatures. These temperature highs are above the level for egg development during the summer when these frogs oviposit under stream substrates. The pacific tailed frogs are also endangered, because they have morphological adaptations and biophysical constraints with temperatures so they are ecologically dependent.

In 2005, Foothill yellow legged frog were commonly encountered in all channels of the river. Their tadpoles are found increasingly at temperatures above 13 degrees Celsius. The adults are often found in open sun, basking on "gravel bars, boulders and cobbles," because they are "heliotherms" (their body temperature warms by sun's rays). Their eggs are deposited in shallow water in open sunlight near their cobbles and boulders. Rough skinned newts can be found in headwater channels or terrestrial habitats. In 2010, Western fence lizards are found along alluvial channels of the river. This number increases as the water temperature and the level of sediment increases. They stay near the warmer climates because their invertebrate prey is more accessible here.