Stormwater, also written storm water, is water that originates from precipitation (storm), including heavy rain and meltwater from hail and snow. Stormwater can soak into the soil (infiltrate) and become groundwater, be stored on depressed land surface in ponds and puddles, evaporate back into the atmosphere, or contribute to surface runoff. Most runoff is conveyed directly as surface water to nearby streams, rivers or other large water bodies without treatment.
The Santa Clara River is an 83 mi (134 km) long river in Ventura and Los Angeles counties in Southern California. It drains parts of four ranges in the Transverse Ranges System north and northwest of Los Angeles, then flows west onto the Oxnard Plain and into the Santa Barbara Channel of the Pacific Ocean.
A dry well or drywell is an underground structure that disposes of unwanted water, most commonly surface runoff and stormwater, in some cases greywater or water used in a groundwater heat pump. It is a gravity-fed, vertical underground system that can capture surface water from impervious surfaces, then store and gradually infiltrate the water into the groundwater aquifer.
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.
Seven Oaks Dam is a 550-foot (170 m) high earth and rock fill embankment dam across the Santa Ana River in the San Bernardino Mountains, about 4 miles (6.4 km) northeast of Redlands in San Bernardino County, southern California. It impounds Seven Oaks Reservoir in the San Bernardino National Forest.
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.
Prado Dam is an earth-fill dry dam across the Santa Ana River at the Chino Hills near Corona, California in Riverside County with the resulting impounded water creating Prado Flood Control Basin reservoir. The U.S. Army Corps of Engineers built the dam in Lower Santa Ana River Canyon. Its primary purpose is flood control and it is the downstream element of the Santa Ana River's flood control system, which is a natural constriction about 30.5 mi (49.1 km) upstream from the ocean. The area upstream from the dam contains 2,255 sq mi (5,840 km2) of the watershed's 2,650 sq mi (6,900 km2). The dam's construction was authorized in 1936 and the flood of 1938 demonstrated its necessity. Construction was completed in 1941. Prado Flood Control Basin also provides water storage for groundwater recharge operations.
The Arroyo Seco, meaning "dry stream" in Spanish, is a 24.9-mile-long (40.1 km) seasonal river, canyon, watershed, and cultural area in Los Angeles County, California. The area was explored by Gaspar de Portolà who named the stream Arroyo Seco as this canyon had the least water of any he had seen. During this exploration he met the Chief Hahamog-na (Hahamonga) of the Tongva Indians.
Hansen Dam is a flood control dam in the northeastern San Fernando Valley, in the Lake View Terrace neighborhood of Los Angeles, California. The dam was built by the U.S. Army Corps of Engineers, Los Angeles District in 1940. Hansen Dam was named after horse ranchers Homer and Marie Hansen, who established a ranch in the 19th century.
Rain gardens, also called bioretention facilities, are one of a variety of practices designed to increase rain runoff reabsorption by the soil. They can also be used to treat polluted stormwater runoff. Rain gardens are designed landscape sites that reduce the flow rate, total quantity, and pollutant load of runoff from impervious urban areas like roofs, driveways, walkways, parking lots, and compacted lawn areas. Rain gardens rely on plants and natural or engineered soil medium to retain stormwater and increase the lag time of infiltration, while remediating and filtering pollutants carried by urban runoff. Rain gardens provide a method to reuse and optimize any rain that falls, reducing or avoiding the need for additional irrigation. A benefit of planting rain gardens is the consequential decrease in ambient air and water temperature, a mitigation that is especially effective in urban areas containing an abundance of impervious surfaces that absorb heat in a phenomenon known as the heat-island effect.
The Ventura River, in western Ventura County in southern California, United States, flows 16.2 miles (26.1 km) from its headwaters to the Pacific Ocean. The smallest of the three major rivers in Ventura County, it flows through the steeply sloped, narrow Ventura Valley, with its final 0.7 miles (1.1 km) through the broader Ventura River estuary, which extends from where it crosses under a 101 Freeway bridge through to the Pacific Ocean.
The Council for Watershed Health (CWH) is a nonprofit environmental organization in the U.S. state of California. It was founded in 1996 by Dorothy Green to preserve, restore, and enhance the Los Angeles and San Gabriel River watersheds. To accomplish this, it has brought together representatives from the regional water agencies, as well as government regulatory agencies ; community and environmental citizen groups; and businesses in the Los Angeles Basin watershed.
Santa Fe Dam is a flood-control dam on the San Gabriel River located in Irwindale in Los Angeles County, California, United States. For most of the year, the 92-foot (28 m)-high dam and its reservoir lie empty, but can hold more than 45,000 acre-feet (56,000,000 m3) of water during major storms. During the dry season, the basin behind the dam is used for groundwater recharge, as well as various recreational activities.
San Gabriel Dam is a rock-fill dam on the San Gabriel River in Los Angeles County, California, within the Angeles National Forest. Completed in 1939, the dam impounds the main stem of the San Gabriel River about 2.5 miles (4.0 km) downstream from the confluence of the river's East and West Forks, which drain a large portion of the San Gabriel Mountains. It is located directly upstream from the Morris Dam. The dam provides flood control, groundwater recharge flows and hydroelectricity for the heavily populated San Gabriel Valley in the Greater Los Angeles metropolitan area.
Santa Anita Dam, also known as Big Santa Anita Dam, is a concrete thin arch dam on Santa Anita Creek in the San Gabriel Mountains of Los Angeles County, California. Owned by the Los Angeles County Flood Control District, the dam serves for flood control, water conservation and debris control. The dam is 225 feet (69 m) high and 612 feet (187 m) long, holding 858 acre-feet (1,058,000 m3) of water with a maximum capacity of 1,028 acre⋅ft (1,268,000 m3). The catchment area for the dam is 10.8 square miles (28 km2). The dam was built between 1923 and 1927. The dam has three valves that control releases of stormwater.
Morris Dam is a concrete gravity dam across the San Gabriel River in the U.S. state of California. It impounds Morris Reservoir, directly downstream of San Gabriel Dam.
Big Tujunga Dam is a 244-foot-high (74 m) concrete arch dam in Los Angeles County, California, spanning Big Tujunga Canyon northeast of Sunland, in the foothills of the San Gabriel Mountains. Completed in 1931, it provides flood control and groundwater recharge for the San Fernando Valley.
Nacimiento Dam is a dam on the Nacimiento River about 10 miles (16 km) northwest of Paso Robles, California in the United States. The primary purpose of the dam is to provide groundwater recharge for agriculture in Monterey County and northern San Luis Obispo County supported by the Salinas Valley aquifer, as well as flood control, domestic water supply, and hydropower. It forms Lake Nacimiento, popular for boating, fishing and camping, and known locally as the "Dragon Lake" due to its shape.
The Government of Los Angeles County is defined and authorized under the California Constitution, California law, and the Charter of the County of Los Angeles. Much of the Government of California is in practice the responsibility of county governments, such as the Government of Los Angeles County. The County government provides countywide services such as elections and voter registration, law enforcement, jails, vital records, property records, tax collection, public health, health care, and social services. In addition the County serves as the local government for all unincorporated areas.
Big Dalton Dam is a multiple arch concrete dam in Los Angeles County, California, built for the Los Angeles County Flood Control District and completed in August 1929. The dam is one of the earliest of the multiple arch "double-wall" buttress designs of engineer Fred A. Noetzli. The 991 acre-foot dam provides water conservation and controls flooding from Big Dalton Canyon, a watershed within the San Dimas Experimental Forest, part of the Angeles National Forest in the San Gabriel Mountains. It is about 4 miles northeast of the city of Glendora and is operated by the Los Angeles County Department of Public Works.
