Lower Colorado River Valley

The Lower Colorado River Valley ("LCRV") is the river region of the lower Colorado River of the southwestern United States in North America that rises in the Rocky Mountains and has its outlet at the Colorado River Delta in the northern Gulf of California in northwestern Mexico, between the states of Baja California and Sonora. This north–south stretch of the Colorado River forms the border between the U.S. states of California/Arizona and Nevada/Arizona,[1] and between the Mexican states of Baja California/Sonora.

It is commonly defined as the region from below Hoover Dam and Lake Mead to its outlet at the northern Gulf of California (Sea of Cortez); it includes the Colorado River proper, canyons, the valley, mountain ranges with wilderness areas, and the floodplain and associated riparian environments. It is home to recreation activities from the river, the lakes created by dams, agriculture, and the home of various cities, communities, and towns along the river, or associated with the valley region. Five Indian reservations are located in the LCRV: the Chemehuevi, Fort Mojave and Colorado River Indian Reservations; at Yuma are the Quechan and Cocopah reservations.

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A section of the LCRV showing the Colorado Desert-(yellow highlight) in west, the Salton Sea, and the three US bordering states on the Colorado River. Portions of the Mexican states of Baja California and Sonora also shown. Proximity to San Diego and the rain shadow of coastal mountains, also shown.

The LCRV, a desert region

View of Trigo Mountains Wilderness, AZ
Trigo Mountains Wilderness, a ridgeline wilderness area on the eastern border of the river proper, 30 miles north of Yuma-Winterhaven. A single 3-foot, (1.1-meter) Buckhorn Cholla cactus is in foreground; creosote bush scrubland on hillsides.

Some of the highest absolute air temperatures (of North America) are recorded in the LCRV, rivaling Death Valley; specifically Bullhead City, Lake Havasu City, Laughlin, Needles, Yuma, or the southeastern deserts of California, west of the Colorado River where extreme heat is the main summertime weather feature. Worldwide, only some deserts found in Africa and in the Middle East stand up with an even hotter summer climate on average. The LCRV is defined by three deserts. The Mojave Desert is in southeast California, southern Nevada, and northwest Arizona. To the south is the Sonoran Desert on both sides of the Colorado River. However an ecozone delineation occurs in the transition from Arizona to southeast California; consequently the western side of the Colorado River is defined as the western Sonoran Desert and given the name Colorado Desert; the ecozone of this western Sonoran Desert extends south into the northwest region of Sonora, Mexico and the extreme northeast of northern Baja California, Mexico.

Colorado watershed
The Colorado River watershed; the LCRV arbitrarily starts south of Lake Mead, at Hoover Dam in Nevada.

The Lower Colorado River Valley is located in the north, and northwestern Sonoran Desert; the Sonoran Desert region proper extends from areas west of the river, and then southeastwards to southeast Arizona, south to the tip of Baja California Sur, eastwards of the Baja Peninsula cordillera, and south through Sonora state, Mexico to the northern border of neighboring Sinaloa.

The LCRV extends about 350 miles (563 km) from Hoover Dam to the Colorado River Delta. The Sonoran Desert itself is more than twice as extensive north-to-south, and about 450 miles (724 km) in width. Two species, Desert Ironwood-(Olneya tesota)[2] and the Lesser Long-nosed Bat, have geographic ranges identical to the Sonoran Desert, and are indicator species of the Sonoran Desert region. The spring flowering of Ironwood, and the bat species migration arrivals also become indicators of annual or multi-year climate trends for regions of the Sonoran Desert.

Ecological threats

The Lower Colorado River Valley subregion of the Sonoran Desert bioregion has multiple threats. Some major threats include urbanization, clearing of land for agriculture, human occupancy – especially as a result of imported external resources, and camping and camptrailers on BLM land. Other threats include harvesting for fuelwood, campfires, etc. of desert ironwood, Olneya tesota, destruction of land by offroad vehicles, especially in sand dunes, and harvesting and manipulation of groundwater.[3]

List of major cities and communities

Complete list of towns, areas, etc, north to south

Feeder-valleys, or included small valleys

Mojave-sonoran deserts

See also

References

  1. ^ "Lower Colorado River Valley" section, Center for Sonoran Desert Studies; [1]
  2. ^ Atlas of United States Trees, Volume 3, Minor Western Hardwoods, Map 103-Olneya tesota
  3. ^ Ecological threats, Lower Colorado River Valley
  • Little. Atlas of United States Trees, Volume 3, Minor Western Hardwoods, Little, Elbert L, 1976, US Government Printing Office. Library of Congress No. 79-653298. Map 103, Olneya tesota.

External links

Ecology

Water Resources, Dams

Big Maria Mountains

The Big Maria Mountains are located in the southeastern part of the U.S. state of California, near the Colorado River and Arizona. The range lies between Blythe and Vidal, and west of U.S. Route 95 in California and east of Midland. The mountains are home to the Eagle Nest Mine and reach an elevation of 1,030 meters, (3,379 ft). A power line that runs from Parker Dam to Yuma, Arizona runs through the range. A smaller range, the Little Maria Mountains, lie to the west of the Big Marias.

Blythe, California

Blythe is a city in Riverside County, California, United States, in the Palo Verde Valley of the Lower Colorado River Valley region, an agricultural area and part of the Colorado Desert along the Colorado River, approximately 224 miles (360 km) east of Los Angeles and 150 miles (240 km) west of Phoenix. Blythe was named after Thomas H. Blythe, a San Francisco financier, who established primary water rights to the Colorado River in the region in 1877. The city was incorporated on July 21, 1916. The population was 20,817 at the 2010 census.

Camp Gaston

Camp Gaston, sometimes called Fort Gaston is a former U. S. Army camp, that was located 3 miles west of the old original course of the Colorado River south of modern Palo Verde, California in Imperial County, California, near Milpitas Wash Road. It was 80 miles (130 km) up river from Fort Yuma, and was active between 1859 and 1867.

Camp Gaston on the Colorado River is not to be confused with the Fort Gaston, located in the Hoopa Valley Indian Reservation on the Trinity River in Northern California from 1859 to 1892. The northern Fort Gaston was for a short time officially designated as Camp Gaston from 1866 to early 1867 before being re-designated as Fort Gaston.

Colorado Desert

California's Colorado Desert is a part of the larger Sonoran Desert. It encompasses approximately 7 million acres (28,000 km2), including the heavily irrigated Coachella and Imperial valleys. It is home to many unique flora and fauna.

Colorado River Indian Tribes

The Colorado River Indian Tribes is a federally recognized tribe consisting of the four distinct ethnic groups associated with the Colorado River Indian Reservation: Chemehuevi, the Mohave, Hopi, and Navajo. The tribe has about 4,277 enrolled members. A total population of 9,485 currently resides within the tribal reservation according to the 2012-2016 American Community Survey data.

Copper Mountains

The Copper Mountains is a minor north-south trending mountain range, only 8 miles long in southwestern Arizona in the southwestern Sonoran Desert.

The Copper Mountains lie east of Yuma, Arizona and east of the Yuma Desert; also east of the Gila and Tinajas Altas Mountains. It lies on an extensive north-sloping desert plain that drains into the Gila River floodplain close to its confluence and outlet into the southern Colorado River in the Lower Colorado River Valley. The Lechuguilla Desert and Coyote Wash lie west of the mountains; the Tule Desert lies east. The highest point is Coyote Peak at 2,808 feet (856 m).

The communities just north at about 10 miles in the Gila River agricultural valley, are Wellton, Noah, Roll, and Tacna, Arizona.

The Copper Mountains lie in the western portion of the Barry M. Goldwater Air Force Range which is used by the MCAS, the Marine Corps Air Station, Yuma; also 3 miles north of the western end of the Cabeza Prieta National Wildlife Refuge.

Dome Rock Mountains

The Dome Rock Mountains are a mountain range in southern La Paz County, Arizona. The range borders the Colorado River on the west and the Colorado River Indian Reservation on the northwest located in the Lower Colorado River Valley. Quartzsite, Arizona lies on the eastern foothills of the range.

The Dome Rock Mountains are on the southwest of the regional Maria fold and thrust belt.

Gila Mountains (Yuma County)

The Gila Mountains of Yuma County are a 26-mile (42 km) long mountain range in southwestern Arizona in the northwest Sonoran Desert.

The Gila Mountains of Yuma County are a northwest-southeast trending mountain system. The fault-blocked mountain range is attached on the south to the Tinajas Altas Mountains which continue southeast into Sonora, Mexico for another 30 miles. The northwest end of the mountains border the southeast Laguna Mountains. The Gila River flows through the Gila Valley between the Gilas and the Lagunas prior to its confluence with the Colorado.

The Gila Mountains are southeast of the confluence of the Colorado and Gila rivers in the Lower Colorado River Valley. The Gila River flows northwest, north around the mountain's north end, then west six miles to the Colorado. On the northeast side of the Gila Range, the low-elevation basin, Dome Valley is created between the Muggins Mountains and the Muggins Mountains Wilderness to the northeast. The block faulted mountain series ends at this confluence location and the Muggins Mountains are at the southern and southwest end of an extensive plain that transitions north towards the Castle Dome Plain and Castle Dome Mountains. This plain is the location of the US Army Yuma Proving Ground on this east-west alluvial plain.

The highest peak in the arid and rugged Gila Mountains is Sheep Peak at 3,156 feet (962 m). The mountain range lies east of Yuma and the community of Fortuna Foothills lies on the northwest mountain range foothills, (named for the Fortuna Mine). The mountain range is located in the western portion of the Barry M. Goldwater Air Force Range which is used by the MCAS, the Marine Corps Air Station, Yuma.

Halchidhoma

The Halchidhoma (Maricopa: Xalychidom Piipaa or Xalychidom Piipaash -'people who live toward the water') are an Indian tribe now living mostly on the Salt River reservation, but formerly native to the area along the lower Colorado River in California and Arizona when first contacted by Europeans. In the early nineteenth century, under pressure from their hostile Mohave and Quechan neighbors, they moved to the middle Gila River, where some merged with the Maricopa, and others went on to Salt River and maintained an independent identity.

The Halchidhoma currently speak the Maricopa language.

Havasu National Wildlife Refuge

Havasu National Wildlife Refuge is a U.S. National Wildlife Refuge on the lower Colorado River in Arizona and California. It preserves habitat for desert bighorn sheep to the endangered southwestern willow flycatcher, birds and other animals. The refuge protects 30 river miles - 300 miles (480 km) of shoreline - from Needles, California, to Lake Havasu City, Arizona. One of the last remaining natural stretches of the lower Colorado River flows through the 20-mile-long (32 km) Topock Gorge.

Animal species that inhabit this refuge include peregrine falcon, coyote, fox, desert bighorn sheep, greater roadrunner, bobcat, and cougar. Thousands of bats emerge from historic mines and razorback suckers swim in the back of Beal Lake.

A large river in a dry, hot land attracts wildlife and people like a powerful magnet. Many thousands of visitors annually flock to the refuge to boat through the Topock Gorge, watch waterbirds in Topock Marsh, or hike to the Havasu Wilderness Area.

A non-profit membership organization supports and advocates for the refuge. It assists refuge staff with several of the refuge annual events, help to obtain grants to support refuge projects, conducts fund-raising activities to support environmental education programs, and helps the United States Fish and Wildlife Service operate and maintain the refuge facilities and programs by providing volunteer labor.

List of dams of the LCRV

This is a List of dams of the Lower Colorado River Valley. There are many smaller dams, check dams, or diversion dams, that lace the length of the Colorado River. The major Davis Dam directly downstream of Hoover Dam has the purpose of re-regulating Hoover Dam releases.

The purpose of this list is to accompany the List of lakes of the LCRV (birdwatching). The many lakes of the LCRV, the Lower Colorado River Valley, provide great opportunities for birdwatching, as well as a proximity to other riparian birdwatching habitats.

Palo Verde Mountains

The Palo Verde Mountains are a mountain range in northeastern Imperial County, California.The Palo Verde Mountains are located along the west side of the Colorado River in the Lower Colorado River Valley and Colorado Desert.

Palo Verde Valley

The Palo Verde Valley is located in the Lower Colorado River Valley, next to the eastern border of Southern California with Arizona, United States. It is located on the Colorado Desert within the Sonoran Desert south of the Parker Valley. Most of the valley is in Riverside County, with the southern remainder in Imperial County. La Paz County borders to the east on the Colorado River.

The region is the ancestral home of several Native American tribes: the Quechan, the Chemehuevi and Matxalycadom or Halchidhoma, some who have Indian reservations in California and Arizona along the Colorado and Gila Rivers today.

Parker, Arizona

Parker (Mojave 'Amat Kuhwely, formerly 'Ahwe Nyava) is the county seat of La Paz County, Arizona, United States, on the Colorado River in Parker Valley. The population was 3,083 at the 2010 census.

Parker Valley

The Parker Valley is located along the Lower Colorado River within the Lower Colorado River Valley region, in southwestern Arizona and southeastern California.

Its natural habitats are within the Sonoran Desert (Arizona) and Colorado Desert (California) ecoregions. Riparian zone habitats on the river include Mesquite Bosques. The river has supported irrigated agricultural conversion of the valley's landscape.

Riverside Mountains

The Riverside Mountains are a mountain range in Riverside County, California. The town of Vidal, California is located in the West Riverside Mountains.

Topock, Arizona

Topock (Mojave: Tuupak) ((Pronounced /'Toe-pock'/ by locals)) is a small unincorporated community in Mohave County, Arizona. Topock has a ZIP Code of 86436; in 2000, the population of the 86436 ZCTA was 1,790.It lies between Bullhead City and Lake Havasu City and southeast of Needles, California, on the California–Arizona border.

Topock is known for being a boating town as well as being home to the Old Trails Arch Bridge which used to be the old Route 66 bridge featured in the film The Grapes of Wrath. The crossings of the Colorado River at Topock, including the Old Trails Arch Bridge, are also featured prominently in the opening credits of the movie Easy Rider.Topock Marina located just off I-40 on Historic Route 66. Situated on the Colorado River between Needles and Lake Havasu City, the Marina is the traditional refueling point for boaters traveling between these two cities.

Topock is the site of one of Pacific Gas & Electric (PG&E)'s recompression stations on its super-rich natural gas pipeline from Texas to San Francisco completed in 1930.

Trigo Mountains

The Trigo Mountains are a north-south trending mountain range in La Paz County, Arizona, bordering the Colorado River on the east in the Lower Colorado River Valley. The range lies north of the Colorado River as it turns east, north of Martinez Lake and the Imperial Reservoir. The Trigo Mountains are on a north-south stretch of the Colorado River, and form the eastern perimeter of the Imperial National Wildlife Refuge.

Turtle Mountains (California)

The Turtle Mountains (Amat 'Achii'ar in the Mojave language), are located in northeastern San Bernardino County, in the southeastern part of California.

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