The Pomona Valley is located in the Greater Los Angeles Area between the San Gabriel Valley and San Bernardino Valley in Southern California. The valley is approximately 30 miles (48 km) east of downtown Los Angeles.
The Santa Ana River is the largest river entirely within Southern California in the United States. It rises in the San Bernardino Mountains and flows for most of its length through San Bernardino and Riverside counties, before cutting through the northern Santa Ana Mountains via Santa Ana Canyon and flowing southwest through urban Orange County to drain into the Pacific Ocean. The Santa Ana River is 96 miles (154 km) long, and its drainage basin is 2,650 square miles (6,900 km2) in size.
The Rio Hondo is a tributary of the Los Angeles River in Los Angeles County, California, approximately 16.4 miles (26.4 km) long. As a named river, it begins in Irwindale and flows southwest to its confluence in South Gate, passing through several cities. Above Irwindale its main stem is known as Santa Anita Creek, which extends another 10 miles (16 km) northwards into the San Gabriel Mountains where the source, or headwaters, of the river are found.
The San Gabriel River is a mostly-urban waterway flowing 58 miles (93 km) southward through Los Angeles and Orange Counties, California, in the United States. It is the central of three major rivers draining the Greater Los Angeles Area, the others being the Los Angeles River and Santa Ana River. The river's watershed stretches from the rugged San Gabriel Mountains to the heavily-developed San Gabriel Valley and a significant part of the Los Angeles coastal plain, emptying into the Pacific Ocean between the cities of Long Beach and Seal Beach.
The San Bernardino Valley is a valley in Southern California located at the south base of the Transverse Ranges. It is bordered on the north by the eastern San Gabriel Mountains and the San Bernardino Mountains; on the east by the San Jacinto Mountains; on the south by the Temescal Mountains and Santa Ana Mountains; and on the west by the Pomona Valley. Elevation varies from 590 feet (180 m) on valley floors near Chino to 1,380 feet (420 m) near San Bernardino and Redlands. The valley floor is home to over 80% of the more than 4 million people in the Inland Empire region.
The Pajaro River is a U.S. river in the Central Coast region of California, forming part of the border between San Benito and Santa Clara Counties, the entire border between San Benito and Santa Cruz County, and the entire border between Santa Cruz and Monterey County. Flowing roughly east to west, the river empties into Monterey Bay, west of Watsonville, California.
The Los Angeles flood of 1938 was one of the largest floods in the history of Los Angeles, Orange, and Riverside Counties in southern California. The flood was caused by two Pacific storms that swept across the Los Angeles Basin in February-March 1938 and generated almost one year's worth of precipitation in just a few days. Between 113–115 people were killed by the flooding. The Los Angeles, San Gabriel, and Santa Ana Rivers burst their banks, inundating much of the coastal plain, the San Fernando and San Gabriel Valleys, and the Inland Empire. Flood control structures spared parts of Los Angeles County from destruction, while Orange and Riverside Counties experienced more damage.
San Juan Creek, also called the San Juan River, is a 29-mile (47 km) long stream in Orange and Riverside Counties, draining a watershed of 133.9 square miles (347 km2). Its mainstem begins in the southern Santa Ana Mountains in the Cleveland National Forest. It winds west and south through San Juan Canyon, and is joined by Arroyo Trabuco as it passes through San Juan Capistrano. It flows into the Pacific Ocean at Doheny State Beach. State Route 74, the Ortega Highway, crosses the Santa Ana Mountains via San Juan Canyon.
Santiago Creek is a major watercourse in Orange County in the U.S. state of California. About 34 miles (55 km) long, it drains most of the northern Santa Ana Mountains and is a tributary to the Santa Ana River. It is one of the longest watercourses entirely within the county. The creek shares its name with Santiago Peak, at 5,687 ft (1,733 m) the highest point in Orange County, on whose slopes its headwaters rise.
San Diego Creek is a 16-mile (26 km) urban waterway flowing into Upper Newport Bay in Orange County, California, United States. Its watershed covers 112.2 square miles (291 km2) in parts of eight cities, including Irvine, Tustin, and Costa Mesa. From its headwaters in Laguna Woods the creek flows northwest to its confluence with Peters Canyon Wash, where it turns abruptly southwest towards the bay. Most of the creek has been converted to a concrete flood control channel, but it also provides important aquatic and riparian habitat along its course and its tidal estuary.
Coyote Creek is a principal tributary of the San Gabriel River in northwest Orange County and southeast Los Angeles County, California. It drains a land area of roughly 41.3 square miles (107 km2) covering eight major cities, including Brea, Buena Park, Fullerton, Hawaiian Gardens, La Habra, Lakewood, La Palma, and Long Beach. Some major tributaries of the creek in the highly urbanized watershed include Brea Creek, Fullerton Creek, and Carbon Creek. The mostly-flat creek basin is separated by a series of low mountains, and is bounded by several small mountain ranges, including the Chino Hills, Puente Hills, and West Coyote Hills.
Brea Creek is one of four principal tributaries of Coyote Creek, which is a lower tributary of the San Gabriel River in California. It drains parts of Orange, Riverside, and San Bernardino counties. The creek flows 11.7 miles (18.8 km) from the cities of Brea and Anaheim to Whittier, where its mouth is on the left bank of Coyote Creek, at a point 481 feet (147 m) lower in elevation.
San Mateo Creek is a stream in Southern California in the United States, whose watershed mostly straddles the border of Orange and San Diego Counties. It is about 22 miles (35 km) long, flowing in a generally southwesterly direction. Draining a broad valley bounded by the Santa Ana Mountains and Santa Margarita Mountains, San Mateo Creek is notable for being one of the last unchannelized streams in Southern California.
Temescal Creek is an approximately 29-mile-long (47 km) watercourse in Riverside County, in the U.S. state of California. Flowing primarily in a northwestern direction, it connects Lake Elsinore with the Santa Ana River. It drains the eastern slopes of the Santa Ana Mountains on its left and on its right the western slopes of the Temescal Mountains along its length. With a drainage basin of about 1,000 square miles (2,600 km2), it is the largest tributary of the Santa Ana River, hydrologically connecting the 720-square-mile (1,900 km2) San Jacinto River and Lake Elsinore watersheds to the rest of the Santa Ana watershed. However, flowing through an arid rain shadow zone of the Santa Ana Mountains, and with diversion of ground water for human use, the creek today is ephemeral for most of its length, except for runoff from housing developments and agricultural return flows.
Hale Creek is a short stream originating in the foothills of Los Altos Hills, California in Santa Clara County, California, United States. Its source is in the Rancho San Antonio Open Space Preserve, west of Neary Quarry. The creek flows northeasterly 4.6 miles (7.4 km) through the cities of Los Altos Hills, Los Altos, and Mountain View before joining Permanente Creek.
San Antonio Creek is a major stream in Los Angeles County and San Bernardino County, California, draining southwards from Mount San Antonio in the San Gabriel Mountains into Chino Creek, a tributary of the Santa Ana River. Upon leaving San Antonio Canyon and entering the broad alluvial plain of the Pomona Valley, it is known as the San Antonio Wash or the San Antonio Creek Channel, the former referring to the creek's seasonal dry nature below the mouth of San Antonio Canyon.
San Timoteo Creek is a stream in Riverside and San Bernardino counties in southern California, United States. A tributary of the Santa Ana River, it flows through San Timoteo Canyon. San Timoteo Creek has a drainage basin of about 125 square miles (320 km2). The creek receives most of its water from headwater tributaries flowing from the San Bernardino Mountains near Cherry Valley, as well as Yucaipa Creek, which flows from Live Oak Canyon.
The Perris Block is the central block of three major fault-bounded blocks of the northern part of the Peninsular Ranges. The Perris Block lies between the Santa Ana Block to the west and the San Jacinto Block to the east. The Perris Block, was named by Walter A. English in 1925 for the city of Perris, located near the center of the block.
