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: 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: 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 Chaco Wash is an arroyo (a periodic stream) cutting through Chaco Canyon, which is located in northwestern New Mexico on the Colorado Plateau. Another arroyo known as Escavada Wash is a tributary that feeds in from the northeast, near the western end of Chaco Canyon. Chaco Wash flows northwest to become the intermittent Chaco River. It is a tributary of the San Juan River.

paragraph_text: The Grand Canyon is a river valley in the Colorado Plateau that exposes uplifted Proterozoic and Paleozoic strata, and is also one of the six distinct physiographic sections of the Colorado Plateau province. It is not the deepest canyon in the world (Kali Gandaki Gorge in Nepal is much deeper). However, the Grand Canyon is known for its visually overwhelming size and its intricate and colorful landscape. Geologically, it is significant because of the thick sequence of ancient rocks that are well preserved and exposed in the walls of the canyon. These rock layers record much of the early geologic history of the North American continent.

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: The Humaya River is a river in the state of Sinaloa, Mexico, that connects to the Tamazula River in the city of Culiacán to form the Culiacán River. The source of the river is the Sierra Madre Occidental mountains. The water flows from the north of the city. The water then flows to the Pacific Ocean.

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: 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: Byers Canyon is a short gorge on the upper Colorado River in Grand County, Colorado in the United States. The canyon is approximately 8 miles (13 km) long and is located in the headwaters region of the Colorado between Hot Sulphur Springs and Kremmling. U.S. Highway 40 passes through the canyon between Hot Sulphur Springs and Kremmling. The Union Pacific Railroad's Moffat Route also travels through the short canyon.

paragraph_text: Although Chihuahua is primarily identified with the Chihuahuan Desert for namesake, it has more forests than any other state in Mexico, with the exception of Durango. Due to its variant climate, the state has a large variety of fauna and flora. The state is mostly characterized by rugged mountainous terrain and wide river valleys. The Sierra Madre Occidental mountain range, an extension of the Rocky Mountains, dominates the state's terrain and is home to the state's greatest attraction, Las Barrancas del Cobre, or Copper Canyon, a canyon system larger and deeper than the Grand Canyon. On the slope of the Sierra Madre Occidental mountains (around the regions of Casas Grandes, Cuauhtémoc and Parral), there are vast prairies of short yellow grass, the source of the bulk of the state's agricultural production. Most of the inhabitants live along the Rio Grande Valley and the Conchos River Valley.

paragraph_text: Water covers 71% of the Earth's surface. It is vital for all known forms of life. On Earth, 96.5% of the planet's crust water is found in seas and oceans, 1.7% in groundwater, 1.7% in glaciers and the ice caps of Antarctica and Greenland, a small fraction in other large water bodies, 0.001% in the air as vapor, clouds (formed of ice and liquid water suspended in air), and precipitation. Only 2.5% of this water is freshwater, and 98.8% of that water is in ice (excepting ice in clouds) and groundwater. Less than 0.3% of all freshwater is in rivers, lakes, and the atmosphere, and an even smaller amount of the Earth's freshwater (0.003%) is contained within biological bodies and manufactured products. A greater quantity of water is found in the earth's interior.

paragraph_text: Water from the Central Arizona Project (CAP) started flowing into Tempe Town Lake on June 2, 1999, and by July 14, the lake was declared full. On November 7, Tempe Town Lake was opened to the public.

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: 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: An autotroph (``self - feeding '', from the Greek autos`` self'' and trophe ``nourishing '') or producer, is an organism that produces complex organic compounds (such as carbohydrates, fats, and proteins) from simple substances present in its surroundings, generally using energy from light (photosynthesis) or inorganic chemical reactions (chemosynthesis). They are the producers in a food chain, such as plants on land or algae in water (in contrast to heterotrophs as consumers of autotrophs). They do not need a living source of energy or organic carbon. Autotrophs can reduce carbon dioxide to make organic compounds for biosynthesis and also create a store of chemical energy. Most autotrophs use water as the reducing agent, but some can use other hydrogen compounds such as hydrogen sulfide. Some autotrophs, like green plants and algae, are phototrophs, meaning that they convert electromagnetic energy from sunlight into chemical energy in the form of reduced carbon.

paragraph_text: Gore Canyon is a short isolated canyon on the upper Colorado River in southwestern Grand County, Colorado in the United States. The steep and rugged canyon, approximately 3 miles (5 km) long, was carved by the river as it passed the northern end of the Gore Range southwest of Kremmling. The Colorado descends from approximately to approximately over the length of the canyon. The steep walls ascend approximately on either side. The canyon effectively marks the southwestern end of the Middle Park basin in north central Colorado.

paragraph_text: To prevent further loss of groundwater, Tucson has been involved in water conservation and groundwater preservation efforts, shifting away from its reliance on a series of Tucson area wells in favor of conservation, consumption-based pricing for residential and commercial water use, and new wells in the more sustainable Avra Valley aquifer, northwest of the city. An allocation from the Central Arizona Project Aqueduct (CAP), which passes more than 300 mi (480 km) across the desert from the Colorado River, has been incorporated into the city's water supply, annually providing over 20 million gallons of "recharged" water which is pumped into the ground to replenish water pumped out. Since 2001, CAP water has allowed the city to remove or turn off over 80 wells.

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: Qarsita () is a Sunni Muslim village located in the highest mountains of Miniyeh-Danniyeh District in North Lebanon. The name of this village is derived from the two Arabic words "Qar" and "Sita" which mean famous ("sita") for cold ("Qar"). The village is famous for cultivation of pears, apples, peaches and variety of fruits and is one of the first producers of pears and apples in Lebanon. The very cold village, in comparison with surrounded areas, is characterized by its nature scenery and its unique position overlooking the city of Tripoli, the towns of Akkar district and the Syrian coast. Qarsita is one of the rich village in fresh water in Miniyeh-Danniyeh District, it contains thousandth of fresh water sources, the biggest one called Source of Sugar feeds a large number of villages in the area.

Question: When did the river that feeds the CAP start to form the Grand Canyon?
Answer: about 5 to 6 million years ago