paragraph_text: The Colorado River originates more than 1,000 miles (1,600 km) from California in the Rocky Mountains of Colorado and Wyoming and forms the state's southeastern border in the Mojave Desert. Unlike the other California watersheds, essentially all of the water flowing in the Colorado originates outside the state. The Colorado is a critical source of irrigation and urban water for southern California, providing between 55 and 65 percent of the total supply.

paragraph_text: The Grand Canyon North Rim Headquarters is a historic district on the North Rim of the Grand Canyon in Grand Canyon National Park, Arizona. Established from 1926 through the 1930s, the district includes examples of National Park Service Rustic architecture as applied to employee residences, administrative facilities and service structures.

paragraph_text: Baccharis brachyphylla is a North American species of shrub in the daisy family, known by the common name shortleaf baccharis or false willow. It is native to the southwestern United States (southern California, southern Nevada, Arizona, southern New Mexico, and western Texas) and northern Mexico (Baja California, Chihuahua, Sonora). It grows in desert habitats such as arroyos and canyons.

paragraph_text: The Grand Canyon (Hopi: Ongtupqa; Yavapai: Wi: kaʼi: la, Navajo: Tsékooh Hatsoh, Spanish: Gran Cañón) is a steep - sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is 277 miles (446 km) long, up to 18 miles (29 km) wide and attains a depth of over a mile (6,093 feet or 1,857 meters).

paragraph_text: Nearly two billion years of Earth's geological history have been exposed as the Colorado River and its tributaries cut their channels through layer after layer of rock while the Colorado Plateau was uplifted. While some aspects about the history of incision of the canyon are debated by geologists, several recent studies support the hypothesis that the Colorado River established its course through the area about 5 to 6 million years ago. Since that time, the Colorado River has driven the down - cutting of the tributaries and retreat of the cliffs, simultaneously deepening and widening the canyon.

paragraph_text: Thistle is a ghost town in Spanish Fork Canyon in southeastern Utah County, Utah, United States. During the era of steam locomotives, the town's primary industry was servicing trains for the Denver and Rio Grande Western Railroad (often shortened to D&RG, D&RGW, or Rio Grande). The fortunes of the town were closely linked with those of the railroad until the changeover to diesel locomotives, when the town started to decline.

paragraph_text: Doheny State Beach is a protected beach in the state park system of California, USA, located on the Pacific Ocean in the city of Dana Point. The beach is a popular surf spot located at the mouth of San Juan Creek, which flows from the Santa Ana Mountains southwest to the beach, where it forms a fresh-water lagoon. It is also one of the most polluted beaches in Southern California.

paragraph_text: Candor Chasma is one of the largest canyons in the Valles Marineris canyon system on Mars. The feature is geographically divided into two halves: East and West Candor Chasmas, respectively. It is unclear how the canyon originally formed; one theory is that it was expanded and deepened by tectonic processes similar to a graben, while another suggests that it was formed by subsurface water erosion similar to a karst. MRO discovered sulfates, hydrated sulfates, and iron oxides in Candor Chasma.

paragraph_text: Bromela is an unincorporated community in San Luis Obispo County, California, United States. Bromela is located along the Old Southern Pacific Railroad(Now Union Pacific) south of Arroyo Grande.

paragraph_text: Get Water! is a mobile game about the water scarcity in India and South Asia, and the effects it has on girls' education. It is developed by the Montreal-based start-up Decode Global Studio, with the goal to create an educational game which is also entertaining and challenging to play. The game was originally released for iOS on 22 March 2013, on World Water Day, and was ported to Android a year later for World Water Day 2014.

paragraph_text: Grand Canyon National Park, located in northwestern Arizona, is the 15th site in the United States to have been named a national park. The park's central feature is the Grand Canyon, a gorge of the Colorado River, which is often considered one of the Wonders of the World. The park, which covers 1,217,262 acres (1,901.972 sq mi; 4,926.08 km) of unincorporated area in Coconino and Mohave counties, received more than six million recreational visitors in 2017, which is the second highest count of all American national parks after Great Smoky Mountains National Park. The Grand Canyon was designated a World Heritage Site by UNESCO in 1979.

paragraph_text: U.S. President Theodore Roosevelt visited the Grand Canyon in 1903. An avid outdoorsman and staunch conservationist, Roosevelt established the Grand Canyon Game Preserve on November 28, 1906. Livestock grazing was reduced, but predators such as mountain lions, eagles, and wolves were eradicated. Roosevelt along with other members of his conservation group, the Boone and Crockett Club helped form the National Parks Association, which in turn lobbied for the Antiquities Act of 1906 which gave Roosevelt the power to create national monuments. Once the act was passed, Roosevelt immediately added adjacent national forest lands and redesignated the preserve a U.S. National Monument on January 11, 1908. Opponents such as land and mining claim holders blocked efforts to reclassify the monument as a U.S. National Park for 11 years. Grand Canyon National Park was finally established as the 17th U.S. National Park by an Act of Congress signed into law by President Woodrow Wilson on February 26, 1919.

paragraph_text: The Diablo Canyon Power Plant is an electricity-generating nuclear power plant near Avila Beach in San Luis Obispo County, California. Since the permanent shutdown of the San Onofre Nuclear Generating Station in 2013, Diablo Canyon is the only operational nuclear plant left in the state. The plant has two Westinghouse-designed 4-loop pressurized-water nuclear reactors operated by Pacific Gas & Electric (PG&E).

paragraph_text: The main mountain range in the state is the Sierra Madre Occidental reaching a maximum altitude of 10,826 ft (3,300 m) known as Cerro Mohinora. Mountains account for one third of the state's surface area which include large coniferous forests. The climate in the mountainous regions varies Chihuahua has more forests than any other state in Mexico making the area a bountiful source of wood; the mountainous areas are rich in minerals important to Mexico's mining industry. Precipitation and temperature in the mountainous areas depends on the elevation. Between the months of November and March snow storms are possible in the lower elevations and are frequent in the higher elevations. There are several watersheds located in the Sierra Madre Occidental all of the water that flows through the state; most of the rivers finally empty into the Río Grande. Temperatures in some canyons in the state reach over 100 °F in the summer while the same areas rarely drop below 32 °F in the winter. Microclimates found in the heart of the Sierra Madre Occidental in the state could be considered tropical, and wild tropical plants have been found in some canyons. La Barranca del Cobre, or Copper Canyon, a spectacular canyon system larger and deeper than the Grand Canyon; the canyon also contains Mexico's two tallest waterfalls: Basaseachic Falls and Piedra Volada. There are two national parks found in the mountainous area of the state: Cumbres de Majalca National Park and Basaseachic Falls National Park.

paragraph_text: The Havasupai people (Havasupai: Havsuw 'Baaja) are an American Indian tribe who have lived in the Grand Canyon for at least the past 800 years. Havasu means ``blue - green water ''and pai`` people''.

paragraph_text: "Southern California" is not a formal geographic designation, and definitions of what constitutes southern California vary. Geographically, California's north-south midway point lies at exactly 37° 9' 58.23" latitude, around 11 miles (18 km) south of San Jose; however, this does not coincide with popular use of the term. When the state is divided into two areas (northern and southern California), the term "southern California" usually refers to the ten southern-most counties of the state. This definition coincides neatly with the county lines at 35° 47′ 28″ north latitude, which form the northern borders of San Luis Obispo, Kern, and San Bernardino counties. Another definition for southern California uses Point Conception and the Tehachapi Mountains as the northern boundary.

paragraph_text: Ma'adim Vallis is one of the largest outflow channels on Mars, about 700 km long and significantly larger than Earth's Grand Canyon. It is over 20 km wide and 2 km deep in some places. It runs from a region of southern lowlands thought to have once contained a large group of lakes (see Eridania Lake) north to Gusev crater near the equator. It looks as if water may have collected in Gusev crater, forming a giant lake; the Spirit Rover was sent there to investigate that possibility, but found only volcanic rocks on the floor of Gusev. Any lake deposits were probably covered over by a later deposit of volcanic materials from Apollinaris Mons, a nearby volcano.

paragraph_text: The Owens River Gorge is a steep 10 mi (16 km) canyon on the upper Owens River in eastern California in the United States. The canyon is located at the eastern edge of the Sierra Nevada mountains in southern Mono County, along the stretch of the river where it exits the Long Valley near its source and enters the north end of Owens Valley. The gorge is a popular destination for rock climbing.

paragraph_text: Mount Goddard is a mountain of California's Sierra Nevada, in the north section of Kings Canyon National Park. Goddard forms the southwest boundary of the Evolution Basin.

paragraph_text: Not long after the baby was born, Claire and Alex Ryan begin a relationship, with Alex planning to propose to her during a party. Claire, Tess, and baby Charlotte are returning from town with party supplies when their Ute hit a pothole and Claire loses control of the vehicle, and coming to a stop with its front wheels dangling off the edge of a cliff. Tess is able to get out and get Charlotte to safety, but can not get Claire's door open before the Ute starts to slide. It goes over the cliff and into a canyon, killing Claire.

Question: When did the the river where Southern California gets most of its water, start to form the Grand Canyon?
Answer: about 5 to 6 million years ago