The Mad River Watershed is approximately 100 miles long and drains about 500 square miles of coastal hills in Humboldt County, California. The river's headwaters are in the Coastal Range near South Kelsey Ridge, in Trinity County. Mountain range elevations are from 6,000 feet at the headwaters to 3,000 feet along the western ridge.
The watershed consists of the Upper Mad River (which begins at the upper headwaters and empties into Matthews Dam on Ruth Lake); the Middle Mad River (which extends from Matthews Dam downstream to the confluence of Cowen Creek); and the Lower Mad River (running from Cowen Creek through the estuary to the Pacific Ocean.
The Indigenous Native People, the Wiyot, the Whilkut, Nongatl and Lassik were the original inhabitants along the river, with the Wiyot occupying the lower Mad River Watershed. The Wiyot People have survived and thrived, with the other tribal groups nearly annihilated by White settlers during the 1860s.
The Mad River was called Baduwa't by the Wiyot People. It is said that the Mad River derived its English name from an incident that occurred in December 1849, when Humboldt Bay was being rediscovered by Dr. Josiah Gregg. At the mouth of the about-to-be-named river, Gregg was getting upset, with curses flying, because he was still taking survey measurements to determine its latitude, while the rest of the party were eager to cross.
Today, the river provides groundwater recharge for agricultural water supplies and is free-flowing for 85 percent of its length. It is the source of drinking water for approximately 65% of Humboldt County’s population.
The river flows through and around a mix of unstable rock and sediment. Surrounding vegetation is coniferous forest (Douglas Fir, Spruce, and Redwood) toward the coast, while upland and interior are mixed hardwood forest, grassland, and in some areas riparian canopy. Much of the old growth forests have been cut down, resulting in old growth forests footprint representing less than 2% of what was once historically present.
The Bureau of Land Management and the USDA Forest Service manage most of the upper one-third of the watershed. The industrial timber lands are owned and managed by a handful of companies including: Green Diamond Resource Company (the largest private land owner in the watershed), Sierra Pacific Industries, and Humboldt Redwood Company. Land uses within the watershed include timber harvest, cattle ranching, agriculture, gravel mining, roads and residential development.
A number of threatened Endangered Species Act (ESA) listed fish live in the river, including: Chinook (Oncorhynchus tshawytscha) and Coho salmon (O. kisutch), summer and winter-run Steelhead (O. mykiss), Eulachon (Thaleichthys pacificus), and Longfin smelt (Spirinchus thaleichthy) are found within the Mad and its estuary. Endangered avian species found within the riparian corridor include the Willow Fly Catcher, Yellow Billed Cuco, Marbled Murrelet and the Western Spotted Owl.
Since 1971, the California Department of Fish and Wildlife has operated the Mad River Fish Hatchery. The hatchery releases about 150,000 juvenile steelhead annually in the spring. It is also used as a rearing facility for salmonids that originate from and will be released back into other basins. The hatchery also raises rainbow trout for local put-and-take fisheries.
The Mad River estuary is recognized for protection by the California Bays and Estuaries Policy. In 1992, the Environmental Protection Agency added the Mad River to the California Clean Water Act impaired water list due to elevated sedimentation/siltation and turbidity. The California North Coast Regional Water Quality Control Board (RWQCB) identified water temperature as an additional impairment to the watershed in 2006.
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