Question: What is the source of the water dividing Arizona from Southern California?

full_context: Document 1: Southern California: The state is most commonly divided and promoted by its regional tourism groups as consisting of northern, central, and southern California regions. The two AAA Auto Clubs of the state, the California State Automobile Association and the Automobile Club of Southern California, choose to simplify matters by dividing the state along the lines where their jurisdictions for membership apply, as either northern or southern California, in contrast to the three-region point of view. Another influence is the geographical phrase South of the Tehachapis, which would split the southern region off at the crest of that transverse range, but in that definition, the desert portions of north Los Angeles County and eastern Kern and San Bernardino Counties would be included in the southern California region due to their remoteness from the central valley and interior desert landscape.
Document 2: Colorado River (Texas): Colorado River Texas The Colorado River in Austin, as seen from Mount Bonnell. Country United States State Texas Source - location Dawson County - elevation 3,280 ft (1,000 m) - coordinates 32 ° 40 ′ 47 ''N 101 ° 43 ′ 51'' W ﻿ / ﻿ 32.67972 ° N 101.73083 ° W ﻿ / 32.67972; - 101.73083 Mouth Matagorda Bay - location Gulf of Mexico, at Matagorda County, Texas - elevation 0 ft (0 m) - coordinates 28 ° 35 ′ 41 ''N 95 ° 58 ′ 59'' W ﻿ / ﻿ 28.59472 ° N 95.98306 ° W ﻿ / 28.59472; - 95.98306 Coordinates: 28 ° 35 ′ 41 ''N 95 ° 58 ′ 59'' W ﻿ / ﻿ 28.59472 ° N 95.98306 ° W ﻿ / 28.59472; - 95.98306 Length 862 mi (1,387 km) Basin 39,900 sq mi (103,341 km) Discharge for Bay City - average 2,609 cu ft / s (74 m / s) - max 84,100 cu ft / s (2,381 m / s) - min 0 cu ft / s (0 m / s) Map of the Colorado River and associated watershed
Document 3: Range Creek: Range Creek, rising in the Book Cliffs in Emery County, Utah, is a high tributary of the Colorado River. It flows into the Green River, a major tributary of the Colorado. The creek flows year around.
Document 4: Geography of California: California is a U.S. state on the western coast of North America. Covering an area of , California is geographically diverse. The Sierra Nevada, the fertile farmlands of the Central Valley, and the arid Mojave Desert of the south are some of the major geographic features of this U.S. state. It is home to some of the world's most exceptional trees: the tallest (coast redwood), most massive (Giant Sequoia), and oldest (bristlecone pine). It is also home to both the highest (Mount Whitney) and lowest (Death Valley) points in the 48 contiguous states.
Document 5: Colorado River Compact: The Colorado River Compact is a 1922 agreement among seven U.S. states in the basin of the Colorado River in the American Southwest governing the allocation of the water rights to the river's water among the parties of the interstate compact. The agreement was signed at a meeting at Bishop's Lodge, near Santa Fe, New Mexico, by representatives of the seven states the Colorado river and its tributaries pass through on the way to Mexico.
Document 6: Roaring Rapids (Colorado River): Roaring Rapids are one of several rapids in the Black Canyon of the Colorado, 10.25 miles above El Dorado Canyon in the Colorado River between Arizona and Nevada.
Document 7: Southern California: "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.
Document 8: Mexico–United States border: The total length of the continental border is 1,954 miles (3,145 km). From the Gulf of Mexico, it follows the course of the Rio Grande (Río Bravo del Norte) to the border crossing at Ciudad Juárez, Chihuahua, and El Paso, Texas. Westward from El Paso -- Juárez, it crosses vast tracts of the Chihuahuan and Sonoran deserts to the Colorado River Delta and San Diego -- Tijuana, before reaching the Pacific Ocean.
Document 9: Mexico–United States border: The total length of the continental border is 3,201 kilometers (1,989 mi). From the Gulf of Mexico, it follows the course of the Rio Grande (Río Bravo del Norte) to the border crossing at Ciudad Juárez, Chihuahua and El Paso, Texas. Westward from El Paso -- Juárez, it crosses vast tracts of the Chihuahuan and Sonoran deserts to the Colorado River Delta and San Diego -- Tijuana, before reaching the Pacific Ocean.
Document 10: Water in California: 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.
Document 11: Colorado River: Colorado River The Colorado River at Horseshoe Bend, Arizona, a few miles below Glen Canyon Dam Countries United States, Mexico States Colorado, Utah, Arizona, Nevada, California, Baja California, Sonora Tributaries - left Fraser River, Blue River, Eagle River, Roaring Fork River, Gunnison River, Dolores River, San Juan River, Little Colorado River, Bill Williams River, Gila River - right Green River, Dirty Devil River, Escalante River, Kanab River, Virgin River, Hardy River Cities Glenwood Springs, CO, Grand Junction, CO, Moab, UT, Page, AZ, Bullhead City, AZ, Lake Havasu City, AZ, Yuma, AZ, San Luis Rio Colorado, SON Source La Poudre Pass - location Rocky Mountains, Colorado, United States - elevation 10,184 ft (3,104 m) - coordinates 40 ° 28 ′ 20 ''N 105 ° 49 ′ 34'' W ﻿ / ﻿ 40.47222 ° N 105.82611 ° W ﻿ / 40.47222; - 105.82611 Mouth Gulf of California - location Colorado River Delta, Baja California -- Sonora, Mexico - elevation 0 ft (0 m) - coordinates 31 ° 54 ′ 00 ''N 114 ° 57 ′ 03'' W ﻿ / ﻿ 31.90000 ° N 114.95083 ° W ﻿ / 31.90000; - 114.95083 Coordinates: 31 ° 54 ′ 00 ''N 114 ° 57 ′ 03'' W ﻿ / ﻿ 31.90000 ° N 114.95083 ° W ﻿ / 31.90000; - 114.95083 Length 1,450 mi (2,334 km) Basin 246,000 sq mi (637,137 km) Discharge for mouth (average virgin flow), max and min at Topock, AZ, 300 mi (480 km) from the mouth - average 22,500 cu ft / s (637 m / s) - max 384,000 cu ft / s (10,900 m / s) - min 422 cu ft / s (12 m / s) Map of the Colorado River basin Wikimedia Commons: Colorado River
Document 12: Southern California: To the east is the Colorado Desert and the Colorado River at the border with Arizona, and the Mojave Desert at the border with the state of Nevada. To the south is the Mexico–United States border.
Document 13: Dolores River: The Dolores River is a tributary of the Colorado River, approximately long, in the U.S. states of Colorado and Utah. The river drains a rugged and arid region of the Colorado Plateau west of the San Juan Mountains. Its name derives from the Spanish "El Rio de Nuestra Señora de Dolores", River of Our Lady of Sorrows. The river was explored and possibly named by Juan Maria Antonio Rivera during a 1765 expedition from Santa Fe.
Document 14: Geography of the United States: West of the Rocky Mountains lies the Intermontane Plateaus (also known as the Intermountain West), a large, arid desert lying between the Rockies and the Cascades and Sierra Nevada ranges. The large southern portion, known as the Great Basin, consists of salt flats, drainage basins, and many small north-south mountain ranges. The Southwest is predominantly a low-lying desert region. A portion known as the Colorado Plateau, centered around the Four Corners region, is considered to have some of the most spectacular scenery in the world. It is accentuated in such national parks as Grand Canyon, Arches, Mesa Verde National Park and Bryce Canyon, among others. Other smaller Intermontane areas include the Columbia Plateau covering eastern Washington, western Idaho and northeast Oregon and the Snake River Plain in Southern Idaho.
Document 15: Grand Canyon: 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).
ground_truth: La Poudre Pass
sub_queries: What is the name of the water body that is found to the east? Answer: Colorado River
what is the source of Colorado River Answer: La Poudre Pass