The Mokelumne River ( or ; ''Mokelumne'',

Miwok The Miwok (also spelled Miwuk, Mi-Wuk, or Me-Wuk) are members of four linguistically related Native Americans in the United States, Native American groups indigenous to what is now Northern California, who traditionally spoke one of the Miwok lan ...

for "People of the Fish Net") is a -long river in

northern California Northern California (commonly shortened to NorCal) is a geocultural region that comprises the northern portion of the U.S. state of California, spanning the northernmost 48 of the state's List of counties in California, 58 counties. Northern Ca ...

in the United States. The river flows west from a rugged portion of the central

Sierra Nevada The Sierra Nevada ( ) is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primari ...

into the Central Valley and ultimately the

Sacramento–San Joaquin River Delta The Sacramento–San Joaquin River Delta, or California Delta, is an expansive inland river delta and estuary in Central California and Northern California Northern California (commonly shortened to NorCal) is a geocultural region that ...

, where it empties into the

San Joaquin River The San Joaquin River ( ; ) is the longest river of Central California. The long river starts in the high Sierra Nevada and flows through the rich agricultural region of the northern San Joaquin Valley before reaching Suisun Bay, San Francis ...

Stockton Deepwater Shipping Channel California’s Green Trade Corridor, is part of the Stockton Deepwater Shipping Channel Stockton Deepwater Shipping Channel, also called the Baldwin-Stockton Deepwater Shipping Channel or Stockton Deep Water Channel, is a manmade deepwater wat ...

. Together with its main tributary, the

Cosumnes River The Cosumnes River is a river in northern California in the United States. It rises on the western slope of the Sierra Nevada and flows approximately into the Central Valley, emptying into the Mokelumne River in the Sacramento-San Joaquin De ...

, the Mokelumne drains in parts of five California counties. Measured to its farthest source at the head of the North Fork, the river stretches for . The river is colloquially divided into the Upper Mokelumne River, which stretches from the

headwaters The headwater of a river or stream is the geographical point of its beginning, specifically where surface runoff water begins to accumulate into a flowing channel of water. A river or stream into which one or many tributary rivers or streams flo ...

Pardee Reservoir Pardee may refer to: People * Pardee (surname) *Pardee Butler, American clergyman and abolitionist Places United States * Pardee, Kansas * Pardee, Virginia * Pardee, West Virginia *Pardee Home The Pardee Home is a house in Oakland, California ...

in the Sierra foothills, and the Lower Mokelumne River, which refers to the portion of the river below

Camanche Dam Camanche Dam is an earthfill dam on the Mokelumne River in the central California, about 20 mi (32 km) from East Lodi. The dam and reservoir lie in the Sierra Nevada foothills in San Joaquin County. Construction of Camanche Dam was star ...

. In its lower course, the Mokelumne is used heavily for irrigation and also provides water for the east

San Francisco Bay Area The San Francisco Bay Area, commonly known as the Bay Area, is a List of regions of California, region of California surrounding and including San Francisco Bay, and anchored by the cities of Oakland, San Francisco, and San Jose, California, S ...

through the

Mokelumne Aqueduct The Mokelumne Aqueduct is a water conveyance system in central California, United States. The aqueduct is supplied by the Mokelumne River and provides water to 35 municipalities in the East Bay in the San Francisco Bay Area. The aqueduct and the ...

. Several major tributaries of the river have been developed for the generation of

hydroelectric power Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

. The name is Plains Miwok and is constructed from ''moke'', meaning

fishnet In the field of textiles, fishnet is hosiery with an open, diamond-shaped knit; it is most often used as a material for stockings, tights, gloves or bodystockings. Fishnet is available in a multitude of colors, although it is most often sport ...

, and ''-umne'', a suffix meaning "people of".Bright, William (1998). ''1500 California Place Names: their origin and meaning''.

University of California Press The University of California Press, otherwise known as UC Press, is a publishing house associated with the University of California that engages in academic publishing. It was founded in 1893 to publish scholarly and scientific works by faculty ...

;

Berkeley Berkeley most often refers to: *Berkeley, California, a city in the United States **University of California, Berkeley, a public university in Berkeley, California *George Berkeley (1685–1753), Anglo-Irish philosopher Berkeley may also refer to ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

, 1998. . The town of

Mokelumne Hill Mokelumne Hill (''Mokelumne'', Miwok for "People of the Fish Net") is a census-designated place (CDP) in Calaveras County, California, United States. The population was 646 at the 2010 census, down from 774 at the 2000 census. It is commonly refer ...

was named for the river in about 1850.

Course

The Mokelumne is formed by the confluence of several forks that rise in the central Sierra Nevada in the

Stanislaus National Forest Stanislaus National Forest is a National forest (United States), U.S. national forest which manages of land in four counties in the Sierra Nevada in Northern California. It was established on February 22, 1897, making it one of the oldest natio ...

. The North Fork is the largest, originating at Highland Lakes at an elevation of . From its source it flows north then west for to Salt Springs Reservoir. Below Salt Springs it receives the Bear River from the north and then passes through the smaller Tiger Creek Reservoir before joining with the Middle Fork southeast of Pine Grove. The lower portion of the North Fork defines the border between Amador and Calaveras Counties. The Middle Fork rises at on the west side of Bailey Ridge, near Ganns. It flows generally west, past Wilseyville and

West Point The United States Military Academy (USMA), commonly known as West Point, is a United States service academies, United States service academy in West Point, New York that educates cadets for service as Officer_(armed_forces)#United_States, comm ...

, to its

confluence In geography, a confluence (also ''conflux'') occurs where two or more watercourses join to form a single channel (geography), channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river (main ...

with the North Fork. The South Fork begins at an elevation of very near the head of the Middle Fork, and flows west , roughly parallel and south of the Middle Fork, to join the Middle Fork about above the confluence of the North and Middle Forks. The confluence of the North and Middle Forks forms the Mokelumne River proper. The main stem flows west-southwest past

into Pardee Reservoir, formed by the -high

Pardee Dam Pardee Dam is a -high structure across the Mokelumne River which marks the boundary between Amador and Calaveras Counties, located in the foothills of the Sierra Nevada approximately northeast of Stockton. History Construction of the Pardee ...

. Below Pardee the river flows directly into

Camanche Reservoir Camanche Reservoir is an artificial lake in the San Joaquin Valley in California in the United States, at the juncture of Amador, Calaveras, and San Joaquin counties. Its waters are impounded by Camanche Dam, which was completed in 1963. Cam ...

, formed by

. The entire stretch of the Mokelumne between the forks and a point just above Camanche Dam defines the Amador—Calaveras county line; below here, it flows westwards into

San Joaquin County San Joaquin County ( ; , meaning " St. Joachim"), officially the County of San Joaquin, is a county located in the U.S. state of California. As of the 2020 United States census, the population was 779,233. The county seat is Stockton. San Jo ...

. The Camanche Dam is the first non-passable barrier for

anadromous Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousa ...

fish. Below Camanche Dam the Mokelumne meanders to its confluence with the San Joaquin River, first continuing southwest out of the Sierra foothills past Lockeford and then turning northwest at Lodi, where the small Woodbridge Dam impounds the river, forming Lodi Lake. The river receives Dry Creek from the east near Thornton and shortly afterwards receives its major tributary, the

, from the northeast. At this point, the river has reached its northernmost point about south of

Sacramento Sacramento ( or ; ; ) is the capital city of the U.S. state of California and the seat of Sacramento County. Located at the confluence of the Sacramento and American Rivers in Northern California's Sacramento Valley, Sacramento's 2020 p ...

. The river continues west then south into the

where it becomes

tidal Tidal is the adjectival form of tide. Tidal may also refer to: * ''Tidal'' (album), a 1996 album by Fiona Apple * Tidal (king), a king involved in the Battle of the Vale of Siddim * TidalCycles, a live coding environment for music * Tidal (servic ...

and splits into a pair of

distributaries A distributary, or a distributary channel is a stream channel that branches off and flows a main stream channel. It is the opposite of a ''tributary'', a stream that flows another stream or river. Distributaries are a result of river bifurca ...

, the North and South Mokelumne River (not to be confused with the North and South Forks in the Mokelumne headwaters) which together encircle the of

Staten Island Staten Island ( ) is the southernmost of the boroughs of New York City, five boroughs of New York City, coextensive with Richmond County and situated at the southernmost point of New York (state), New York. The borough is separated from the ad ...

. About downstream the branches rejoin, and two miles (3.2 km) below this point the Mokelumne flows into the San Joaquin River.

Watershed

The Mokelumne River

watershed Watershed may refer to: Hydrology * Drainage divide, the line that separates neighbouring drainage basins * Drainage basin, an area of land where surface water converges (North American usage) Music * Watershed Music Festival, an annual country ...

drains in parts of

Alpine Alpine may refer to any mountainous region. It may also refer to: Places Europe * Alps, a European mountain range ** Alpine states, which overlap with the European range Australia * Alpine, New South Wales, a Northern Village * Alpine National P ...

, Amador, Calaveras, San Joaquin, and

Counties. Elevations range from sea level at the confluence with the San Joaquin River to at the crest of the Sierra Nevada in the headwaters of the North Fork. The Mokelumne watershed divide borders the basins of the

American River The American River is a List of rivers of California, river in California that runs from the Sierra Nevada (U.S.), Sierra Nevada mountain range to its confluence with the Sacramento River in downtown Sacramento. Via the Sacramento River, it ...

on the north, the Calaveras and Stanislaus rivers to the south, and the

Carson River The Carson River is a northwestern Nevada river that empties into the Carson Sink, an endorheic basin. The main stem of the river is long although the addition of the East Fork makes the total length , traversing five counties: Alpine Count ...

to the east. The American, Calaveras and Stanislaus rivers, like the Mokelumne, drain westwards into the Central Valley, while the Carson flows eastwards into the

Great Basin The Great Basin () is the largest area of contiguous endorheic watersheds, those with no outlets to the ocean, in North America. It spans nearly all of Nevada, much of Utah, and portions of California, Idaho, Oregon, Wyoming, and Baja Californi ...

. Drainage within the Mokelumne watershed generally occurs from east to west with all of the

perennial stream A stream is a continuous body of surface water flowing within the bed and banks of a channel. Depending on its location or certain characteristics, a stream may be referred to by a variety of local or regional names. Long, large stream ...

s originating in the Sierra Nevada. The Mokelumne River and its headwater forks above Lodi drain the southernmost part of the basin. The part of the basin above Pardee Dam is referred to as the Upper Mokelumne River Basin and drains about , or 25.7% of the total watershed. The Cosumnes River and its own North, Middle and South forks drain about in the northern part of the basin, or about 33.8% of the total watershed. Dry Creek, which itself is formed by four Sierra streams – Jackson, Sutter, Amador and Rancheria Creeks – drains most of the area between the upper Mokelumne and Cosumnes basins, or about . The upper watershed is situated principally in Alpine, Amador and Calaveras Counties and consists mostly of wilderness managed under various federal designations. Most of the Mokelumne and Cosumnes River headwaters lie within the Stanislaus and Eldorado National Forests. Much of the upper watershed is also protected under the

Mokelumne Wilderness The Mokelumne Wilderness is a federally designated wilderness area located east of Sacramento, California. It is within the boundaries of three national forests: Stanislaus, Eldorado and Toiyabe. First protected under the Wilderness Act of ...

. The Salt Springs State Game Refuge is located along the Mokelumne River near Salt Springs Reservoir. There are also significant private holdings in the upper basin including commercial timber land and protected watershed areas administered by the

East Bay Municipal Utility District East Bay Municipal Utility District (EBMUD), colloquially referred to as "East Bay Mud", is a public utility district which provides water and sewage treatment services for an area of approximately in the eastern side of San Francisco Bay.Sectio ...

, which diverts urban and industrial water from Pardee Reservoir. The lower watershed, mainly within San Joaquin and Sacramento Counties, is part of the rich agricultural region of the Central Valley. Grapes are the major crop grown in the Mokelumne River watershed; as of 2001,

vineyard A vineyard ( , ) is a plantation of grape-bearing vines. Many vineyards exist for winemaking; others for the production of raisins, table grapes, and non-alcoholic grape juice. The science, practice and study of vineyard production is kno ...

s comprised 51% of the basin's farmland. Of the remaining land, 31% is used for

livestock Livestock are the Domestication, domesticated animals that are raised in an Agriculture, agricultural setting to provide labour and produce diversified products for consumption such as meat, Egg as food, eggs, milk, fur, leather, and wool. The t ...

, 9% for orchards, and 8% for annual crops. About in the lower basin are part of the Mokelumne River AVA. In May 2021, it was reported that a trove of 5- to 10-million-year-old fossils was unearthed in June 2020 in the Mokelumne River watershed near

Valley Springs, California Valley Springs (formerly known as Spring Valley and Valley Spring) is a census-designated place (CDP) in Calaveras County, California, United States, in the foothills of the Sierra Nevada Mountain Range. Valley Springs is registered as a Califor ...

, including a two-tusked

mastodon A mastodon, from Ancient Greek μαστός (''mastós''), meaning "breast", and ὀδούς (''odoús'') "tooth", is a member of the genus ''Mammut'' (German for 'mammoth'), which was endemic to North America and lived from the late Miocene to ...

, a four-tusked

gomphothere Gomphotheres are an extinct group of proboscideans related to modern elephants. First appearing in Africa during the Oligocene, they dispersed into Eurasia and North America during the Miocene and arrived in South America during the Pleistocene a ...

rhinoceros A rhinoceros ( ; ; ; : rhinoceros or rhinoceroses), commonly abbreviated to rhino, is a member of any of the five extant taxon, extant species (or numerous extinct species) of odd-toed ungulates (perissodactyls) in the family (biology), famil ...

camel A camel (from and () from Ancient Semitic: ''gāmāl'') is an even-toed ungulate in the genus ''Camelus'' that bears distinctive fatty deposits known as "humps" on its back. Camels have long been domesticated and, as livestock, they provid ...

horse The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 mi ...

tortoise Tortoises ( ) are reptiles of the family Testudinidae of the order Testudines (Latin for "tortoise"). Like other turtles, tortoises have a shell to protect from predation and other threats. The shell in tortoises is generally hard, and like o ...

tapir Tapirs ( ) are large, herbivorous mammals belonging to the family Tapiridae. They are similar in shape to a Suidae, pig, with a short, prehensile nose trunk (proboscis). Tapirs inhabit jungle and forest regions of South America, South and Centr ...

, bird, fish, and other specimens.

History

The Mokelumne River basin was originally inhabited by

Yokuts The Yokuts (previously known as MariposasPowell, 1891:90–91.) are an ethnic group of Native Americans native to central California. Before European contact, the Yokuts consisted of up to 60 tribes speaking several related languages. Yokuts ...

, and

Wintun The Wintun are members of several related Native American peoples of Northern California, including the Wintu (northern), Nomlaki (central), and Patwin (southern).Pritzker, 152Plains Miwok; various subgroups that lived in the Mokelumne River basin included the Mokellos, Lalas, and Machacos. The Miwoks called the river ''Wakalumitch'', possibly meaning "big river". The first European parties to explore the river were likely Spanish military expeditions in

Alta California Alta California (, ), also known as Nueva California () among other names, was a province of New Spain formally established in 1804. Along with the Baja California peninsula, it had previously comprised the province of , but was made a separat ...

in the late 18th or early 19th century. The name Mokelumne was first recorded by Spanish missionary

Narciso Durán Narciso Durán, OFM ( Catalan: Narcís Duran; December 16, 1776 – June 4, 1846) was a Spanish Franciscan friar and missionary. Durán arrived in California in 1806 after studying briefly at the missionary College of San Fernando de Mexico. He ...

as ''Muquelumnes'' in 1817. However it was not until 1830 when the first permanent European settlement was established on the Mokelumne River, at Happy Valley near present-day

, as an outpost for French fur trappers.

John C. Frémont Major general (United States), Major-General John Charles Frémont (January 21, 1813July 13, 1890) was a United States Army officer, explorer, and politician. He was a United States senator from California and was the first History of the Repub ...

is credited with establishing the modern spelling of the name Mokelumne circa 1844. During the

California Gold Rush The California gold rush (1848–1855) began on January 24, 1848, when gold was found by James W. Marshall at Sutter's Mill in Coloma, California. The news of gold brought approximately 300,000 people to California from the rest of the U ...

, the Mokelumne was a major gold-producing stream. The first person to discover gold in the Mokelumne was likely Charles Weber in 1848. Weber did not stay in the area for long; he moved on to the Coloma diggings on the South Fork American River before establishing a supply center at present-day Stockton, several miles south of the Mokelumne River. Most of the Gold Rush profits and trade on the Mokelumne River would end up passing through Stockton. Also in 1848, Samuel W. Pearsall found gold at Mokelumne Hill, which by 1850 grew into a boomtown of 15,000 people.

Recreational uses

The Mokelumne River is home to five notable

whitewater kayaking Whitewater kayaking is an outdoor adventure sport where paddlers navigate a river in a specially designed kayak. Whitewater kayaking includes several styles: river running, creeking, slalom, playboating, and squirt boating. Each style offers ...

runs: Fantasy Falls, Devil's Nose, Tiger Creek Dam, Ponderosa and Electra-Middle Bar. Fantasy Falls, a Class V+, 26-mile wilderness reach, runs from below Highway 4 in Alpine County to the backwaters of Salt Springs Reservoir. Devil's Nose, Class IV-V, runs 17 miles from Salt Springs Dams to Tiger Creek Powerhouse. Below Tiger Creek Dam is the Tiger Creek Dam

Whitewater Whitewater forms in the context of rapids, in particular, when a river's Stream gradient, gradient changes enough to generate so much turbulence that air is trapped within the water. This forms an unstable current that foam, froths, making t ...

run, a scenic, 3 mile Class IV run. The Ponderosa run goes from Ponderosa Way to Electra Powerhouse. The westernmost run is Electra-Middle Bar, a 5+-mile Class II-III run. It begins just below the Electra Powerhouse, passes under Highway 49 south of Jackson, CA and ends at the Middle Bar Bridge. The Mokelumne is also a popular site for fishing, camping, water play, birding, picnics, gold panning, spring wildflower watching, and other activities. Electra Road, just east of Highway 49, is a popular place to run, walk, and enjoy the river. The large granite domes, Calaveras Dome and

Hammer Dome Hammer Dome, is a granite dome in the Tuolumne Meadows area of Yosemite National Park. Hammer Dome is a bit north, of Cathedral Creek, which has its source, near Cathedral Peak. Hammer Dome is loosely northwest of Fairview Dome, is north of both ...

, near Salt Springs Reservoir, are popular for technical rock climbing. Three campgrounds are also located near Salt Springs: Mokelumne River, White Azalea, and Moore Creek. Above Salt Springs Reservoir, the Mokelumne Wilderness challenges those who seek a true wilderness experience. Backpacking in this federally designated wilderness area requires good back-country skills. Downstream, the river is also a popular recreational destination, particularly the day-use area at the base of the Camanche Dam, which includes the

Mokelumne River Fish Hatchery The Mokelumne River River Fish Hatchery is a fish hatchery in San Joaquin County, California, built in 1963 by the East Bay Municipal Utility District (EBMUD). History The hatchery was built in 1963 to offset the loss of fish spawning habitat due ...

, and Lodi Lake, a

city park An urban park or metropolitan park, also known as a city park, municipal park (North America), public park, public open space, or municipal gardens ( UK), is a park or botanical garden in cities, densely populated suburbia and other incorporate ...

in the small town of Lodi. The

California Office of Environmental Health Hazard Assessment The Office of Environmental Health Hazard Assessment, commonly referred to as OEHHA (pronounced oh-EEE-ha), is a specialized department within the cabinet-level California Environmental Protection Agency (CalEPA) with responsibility for evaluati ...

(OEHHA) has developed a safe eating advisory for Lower Mokelumne River based on levels of mercury or

PCBs Polychlorinated biphenyls (PCBs) are organochlorine compounds with the formula C12 H10−''x'' Cl''x''; they were once widely used in the manufacture of carbonless copy paper, as heat transfer fluids, and as dielectric and coolant fluids f ...

found in fish caught from this water body.

River modifications

The first diversions of the Mokelumne were made during the

in the mid-1850s to provide water for placer and

hydraulic mining Hydraulic mining is a form of mining that uses high-pressure jets of water to dislodge rock material or move sediment.Paul W. Thrush, ''A Dictionary of Mining, Mineral, and Related Terms'', US Bureau of Mines, 1968, p.560. In the placer mining of ...

. The first

irrigation Irrigation (also referred to as watering of plants) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has bee ...

scheme was organized by a local collective, the Mokelumne Ditch and Irrigation Company, in 1875, but their dam was demolished by a flood and never rebuilt. The Woodbridge Canal and Irrigation Company was founded in 1891, and was somewhat more successful at tapping Mokelumne River water, but they were still hampered by damaging spring floods and lack of water in the dry season. In 1929 the East Bay Municipal Utilities District (EBMUD) built the large

several miles upstream from Lodi and the irrigation diversion points on the Mokelumne River. Pardee is the primary storage facility and diversion point for the Mokelumne Aqueduct, which provides water to 35 municipalities in the eastern

Alameda An alameda is a street or path lined with trees () and may refer to: Places Canada * Alameda, Saskatchewan, town in Saskatchewan ** Grant Devine Dam, formerly ''Alameda Dam'', a dam and reservoir in southern Saskatchewan Chile * Alameda (Santi ...

and Contra Costa Counties. The first water deliveries to the Bay Area were made on June 23, 1929. The dam can store about which is slightly over one quarter of the Mokelumne's annual flow. Through an agreement between EBMUD and local farmers, Pardee also stabilized the dry season water level in the lower Mokelumne, allowing much greater use of the river for agriculture. As early as 1897, the Mokelumne was utilized for the generation of hydroelectric power at the Blue Lakes powerhouse, near Jackson, to provide power for local communities.

Pacific Gas and Electric The Pacific Gas and Electric Company (PG&E) is an American investor-owned utility (IOU). The company is headquartered at Kaiser Center, in Oakland, California. PG&E provides natural gas and electricity to 5.2 million households in the norther ...

(PG&E) began to develop the river for hydroelectricity in the late 1800s. In 1925, the Mokelumne hydroelectric project was licensed, and its major dam, Salt Springs, was completed on the North Fork of the Mokelumne in 1931. The project also includes two dams on the Bear River, the Tiger Creek Dam, and several smaller reservoirs in the Mokelumne headwaters. The project can provide a maximum output of 206

megawatt The watt (symbol: W) is the unit of Power (physics), power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantification (science), quantify the rate of Work ...

s of electricity from four powerhouses. In 1963

was built directly below Pardee to capture additional Mokelumne River runoff. Its primary purpose is to provide flood control for downstream communities, which allows more water to be retained in Pardee Reservoir for the Bay Area's use. Camanche forms the largest reservoir on the Mokelumne with a capacity of . The dam regulates releases from Pardee for local uses, primarily irrigation, and provides flood control for the lower Mokelumne River. The dam is also operated by EBMUD. The Mokelumne River in the Delta forms part of the water pathway for the

Central Valley Project The Central Valley Project (CVP) is a federal power and water management project in the U.S. state of California under the supervision of the United States Bureau of Reclamation (USBR). It was devised in 1933 in order to provide irrigation and ...

and

State Water Project The California State Water Project, commonly known as the SWP, is a state water management project in the U.S. state of California under the supervision of the California Department of Water Resources. The SWP is one of the largest public water ...

, which divert

Sacramento River The Sacramento River () is the principal river of Northern California in the United States and is the largest river in California. Rising in the Klamath Mountains, the river flows south for before reaching the Sacramento–San Joaquin River D ...

water to a number of aqueducts that supply central and southern California. The Sacramento River is connected to the Mokelumne River by the Delta Cross Channel, which enables the large pump stations near Tracy to draw water south across the Delta via the Mokelumne, San Joaquin,

Old River Old River may refer to: * Old River (Belize) * Old River (Tasmania), Australia * The Old River, in the Australian state of Victoria In the United States: * Old River (Clay County, Arkansas) a lake in Clay County, Arkansas * Old River (Cross Co ...

and Middle River.

Ecology

The Mokelumne River provides habitat for

Pacific salmon ''Oncorhynchus'', from Ancient Greek ὄγκος (''ónkos''), meaning "bend", and ῥύγχος (''rhúnkhos''), meaning "snout", is a genus of ray-finned fish in the subfamily Salmoninae of the family Salmonidae, native to coldwater tributarie ...

and

steelhead trout Steelhead, or occasionally steelhead trout, is the anadromous form of the coastal rainbow trout or Columbia River redband trout (''O. m. gairdneri'', also called redband steelhead). Steelhead are native to cold-water tributaries of the Pacif ...

spawning runs. These fish were historically able to migrate upstream of the present site of Pardee Dam, before a natural waterfall prevented further progress. Between 1950 and 1997 the annual fall

chinook salmon The Chinook salmon (''Oncorhynchus tshawytscha'') is the largest and most valuable species of Oncorhynchus, Pacific salmon. Its common name is derived from the Chinookan peoples. Other vernacular names for the species include king salmon, quinn ...

run has had an estimated average of 3434 fish. The construction of Camanche Dam has blocked access to several miles of the highest quality habitat formerly available to salmonids in the Mokelumne River. To compensate for the lost habitat, the

was built in 1964, a year after the completion of Camanche Dam. The Lower Mokelumne River is home to at least 35 species of fish. In addition to salmon and trout, common native fish include prickly sculpin ('' Cottus asper''), and Sacramento sucker ( ''Catostomus occidentalis''). The non-native western mosquitofish (''

Gambusia affinis The western mosquitofish (''Gambusia affinis'') is a North American freshwater poeciliid fish, also known commonly, if ambiguously, as simply mosquitofish or by its generic name, ''Gambusia'', or by the common name gambezi. Its sister species ...

''), largemouth bass (''

Micropterus salmoides The largemouth bass (''Micropterus nigricans'') is a carnivorous, freshwater, ray-finned fish in the Centrarchidae (sunfish) family, native to the eastern and central United States, southeastern Canada and northern Mexico. It is known by a v ...

'') and bluegill (''

Lepomis macrochirus The bluegill (''Lepomis macrochirus''), sometimes referred to as "bream", "brim", "sunny", or, in Texas, "copper nose", is a species of North American freshwater fish, native to and commonly found in streams, rivers, lakes, ponds and wetlands ea ...

'') are also plentiful. The Cosumnes River, the Mokelumne's major tributary, is one of only a few Sierra rivers without large dams; however, irrigation diversions have also caused problems with fish migration on this river. For

water conservation Water conservation aims to sustainably manage the natural resource of fresh water, protect the hydrosphere, and meet current and future human demand. Water conservation makes it possible to avoid water scarcity. It covers all the policies, strateg ...

reasons, local agriculture has switched from flood irrigation to drip and sprinkler systems, and thereby become more reliant on groundwater. This is an issue since the State of California currently does not consider groundwater recharge a beneficial use. North San Joaquin Water Conservation District has the authority to work on this but many other nearby water districts do not.

Recent conflicts

In its original 2040 long-range water plan, issued in 2009, the

approved an optional expansion of Pardee Reservoi

The expansion would have flooded more than a mile of the river as well as unique cultural and historic sites. A broad coalition of local governments, conservation
recreation
an
fishery advocates
opposed the reservoir expansion. Foothill Conservancy, Friends of the Rive

and California Sportfishing Protection Allianc

sued EBMUD in November 2009. In April 2011, Sacramento Superior Court Judge Timothy M. Frawley ruled in the groups' favor and voided the EBMUD plan. On December 5, 2011,

announced that the soon-to-be released revised draft environmental impact report for its revised water plan would not recommend the controversial reservoir expansion. On April 24, 2012, the utility's board voted 7–0 to remove the Pardee expansion from its 2040 water plan.

Conservation and restoration

Mokelumne River North Fork near West Point

In 1999, federal and state agencies joined nonprofit organizations and PG&E in signing a settlement agreement for the new Federal Energy Regulatory Commission license of PG&E's hydroelectric project on the Mokelumne, known as Project 137. The agreement requires flows from the hydroelectric project to follow the natural hydrograph of the river, required the removal or dismantling of three small dams on tributary streams, improved recreational flows and facilities on the river, and incorporated an

adaptive management Adaptive management, also known as adaptive resource management or adaptive environmental assessment and management, is a structured, iterative process of robust decision making in the face of uncertainty, with an aim to reducing uncertainty ove ...

plan with a monitoring program. The removal of West Panther Creek Dam in 2003 was the first removal of a PG&E dam in modern history. Since the signing of the settlement and issuance of the FERC license, the signatories have collaboratively managed the project's adaptive management and monitoring program. About 37 miles of the Mokelumne from Salt Springs Powerhouse to just below Highway 49 have been found eligible for National Wild and Scenic River designation by the U.S. Forest Service and Bureau of Land Management as part of those agencies' land management planning responsibilities. In 2014, Sen. Loni Hancock (D-Oakland) introduced Senate Bill 1199 in the California State Senate to designate the river as Wild and Scenic from Salt Springs to Pardee Reservoir. The legislation was co-sponsored by Foothill Conservancy and Friends of the River, and supported by Calaveras County and a number of conservation, fish, community and tribal groups. It was opposed by Amador County and local water agencies. The East Bay Municipal Utility District initially opposed the bill but supported it with proposed author's amendments late in the legislative process. SB 1199 was passed by the Senate but stalled in the State Assembly, where it was held "in suspense" by the Appropriations Committee after approval by the Natural Resources Committee. In 2015, California Assemblyman Frank Bigelow (R-O'Neals) and Senator Tom Berryhill (R-Twain Harte) co-sponsored state legislation, Assembly Bill 142, which called for completion of a state study before the Mokelumne could be designated a California Wild and Scenic River. After a number of amendments were made to the bill, it was adopted by the Legislature and signed into law by Governor Jerry Brown. The bill mandated a state wild and scenic river suitability study of the Mokelumne and provided interim protections for the river from Salt Springs Dam to Pardee Reservoir. The compromise bill was supported by Sierra foothill water agencies, the East Bay Municipal Utility District and river and fish conservation groups. In January 2018, the California Natural Resources Agency released its draft ''Mokelumne River Wild and Scenic River Study''. The study was finalized after extensive, overwhelmingly positive, public comments and with support for final recommendation language from Mokelumne-dependent water agencies, Amador and Calaveras counties, and conservation groups
The final report
issued in April 2018, recommended adding approximately 37 miles of the North Fork and main Mokelumne to the California Wild and Scenic Rivers System. The report's recommendation was incorporated into the natural resources budget trailer bill, Senate Bill 854, which was passed by the state legislature. The bill was signed into law by Governor Jerry Brown on June 27, 2018. The enactment of the legislation makes the Mokelumne the 15th river included in the California Wild and Scenic Rivers System. In 2014, Foothill Conservancy, other conservation and fish organizations, and federal and state agencies formed a working group to explore restoring salmon and steelhead above Camanche and Pardee reservoirs. The group's work is in progress.

Tributaries

* Dry Creek *

* Bear River * Blue Creek * Beaver Creek * Green Creek * Camp Creek *

Ashland Creek Ashland Creek is a tributary of Bear Creek in the U.S. state of Oregon. It joins Bear Creek near Ashland, from the larger stream's confluence with the Rogue River. The main stem of Ashland Creek begins at Reeder Reservoir, an artificial im ...

References

External links

Lodi News-Sentinel: Searching for the Mokelumne Part IIEPA: Lower Mokelumne watershedEBMUD's Mokelumne historyFantasy Falls kayaking videoAmador Ledger-Dispatch: Mokelumne Frustrations Flow Toward EBMUDIndymedia: Chris Shutes of CSPA Slams Pardee Reservoir Expansion ProjectEast Bay Express: Sierra Water GrabMokelumne River Wild and Scenic video by Mikey Wier
{{Authority control Rivers of the Sierra Nevada (United States) Tributaries of the San Joaquin River Rivers of Amador County, California Rivers of Calaveras County, California Rivers of San Joaquin County, California Rivers of Sacramento County, California East Bay Municipal Utility District Geography of the San Joaquin Valley Rivers of Northern California Rivers of the Sierra Nevada in California