A dam is a barrier that stops or restricts the flow of water or underground streams. Reservoirs created by dams not only suppress floods but provide water for activities such as irrigation, human consumption, industrial use and navigability. Hydropower is used in conjunction with dams to generate electricity. A dam can be used to collect water or for storage of water which can be evenly distributed between locations. Dams serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions; the earliest known dam is the Jawa Dam in Jordan, dating to 3,000 BC. The word dam can be traced back to Middle English, before that, from Middle Dutch, as seen in the names of many old cities; the first known appearance of dam occurs in 1165. However, there is one village, mentioned in 1120; the word seems to be related to the Greek word taphos, meaning "grave" or "grave hill". So the word should be understood as "dike from dug out earth".
The names of more than 40 places from the Middle Dutch era such as Amsterdam and Rotterdam bear testimony to the use of the word in Middle Dutch at that time. Early dam building took place in the Middle East. Dams were used to control the water level, for Mesopotamia's weather affected the Tigris and Euphrates rivers; the earliest known dam is the Jawa Dam in Jordan, 100 kilometres northeast of the capital Amman. This gravity dam featured an 9-metre-high and 1 m-wide stone wall, supported by a 50 m-wide earth rampart; the structure is dated to 3000 BC. The Ancient Egyptian Sadd-el-Kafara Dam at Wadi Al-Garawi, located about 25 km south of Cairo, was 102 m long at its base and 87 m wide; the structure was built around 2800 or 2600 BC as a diversion dam for flood control, but was destroyed by heavy rain during construction or shortly afterwards. During the Twelfth Dynasty in the 19th century BC, the Pharaohs Senosert III, Amenemhat III and Amenemhat IV dug a canal 16 km long linking the Fayum Depression to the Nile in Middle Egypt.
Two dams called Ha-Uar running east-west were built to retain water during the annual flood and release it to surrounding lands. The lake called "Mer-wer" or Lake Moeris is known today as Birket Qarun. By the mid-late third millennium BC, an intricate water-management system within Dholavira in modern-day India was built; the system included 16 reservoirs and various channels for collecting water and storing it. One of the engineering wonders of the ancient world was the Great Dam of Marib in Yemen. Initiated somewhere between 1750 and 1700 BC, it was made of packed earth – triangular in cross section, 580 m in length and 4 m high – running between two groups of rocks on either side, to which it was linked by substantial stonework. Repairs were carried out during various periods, most important around 750 BC, 250 years the dam height was increased to 7 m. After the end of the Kingdom of Saba, the dam fell under the control of the Ḥimyarites who undertook further improvements, creating a structure 14 m high, with five spillway channels, two masonry-reinforced sluices, a settling pond, a 1,000 m canal to a distribution tank.
These extensive works were not finalized until 325 AD and allowed the irrigation of 25,000 acres. Eflatun Pınar is a Hittite spring temple near Konya, Turkey, it is thought to be from the time of the Hittite empire between the 15th and 13th century BC. The Kallanai is constructed of unhewn stone, over 300 m long, 4.5 m high and 20 m wide, across the main stream of the Kaveri river in Tamil Nadu, South India. The basic structure dates to the 2nd century AD and is considered one of the oldest water-diversion or water-regulator structures in the world, still in use; the purpose of the dam was to divert the waters of the Kaveri across the fertile delta region for irrigation via canals. Du Jiang Yan is the oldest surviving irrigation system in China that included a dam that directed waterflow, it was finished in 251 BC. A large earthen dam, made by Sunshu Ao, the prime minister of Chu, flooded a valley in modern-day northern Anhui province that created an enormous irrigation reservoir, a reservoir, still present today.
Roman dam construction was characterized by "the Romans' ability to plan and organize engineering construction on a grand scale." Roman planners introduced the then-novel concept of large reservoir dams which could secure a permanent water supply for urban settlements over the dry season. Their pioneering use of water-proof hydraulic mortar and Roman concrete allowed for much larger dam structures than built, such as the Lake Homs Dam the largest water barrier to that date, the Harbaqa Dam, both in Roman Syria; the highest Roman dam was the Subiaco Dam near Rome. Roman engineers made routine use of ancient standard designs like embankment dams and masonry gravity dams. Apart from that, they displayed a high degree of inventiveness, introducing most of the other basic dam designs, unknown until then; these include arch-gravity dams, arch dams, buttress dams and multiple arch buttress dams, all of which were known and employed by the 2nd century AD. Roman workforces were the first to build dam bridges, such as the Bridge of Valerian in Iran
Santa Anita Creek
Santa Anita Creek is a 10.4-mile long stream in Los Angeles County, California. It flows southwards from its headwaters in the south ridge of the San Gabriel Mountains, to form the beginnings of the Rio Hondo near Irwindale; the creek begins inside the Angeles National Forest. It flows in a curve southeast through Santa Anita Canyon drops over the 60-foot Sturtevant Falls; the North Fork comes in from the left about a quarter-mile above the falls, the East Fork from the left about a quarter-mile downstream. The creek flows south through a group of about 80 historic cabins on the canyon floor, before receiving Winter Creek from the right near Chantry Flat. Shortly downstream of there, it drops over Hermit Falls and flows into Santa Anita Reservoir, impounded by the 225-foot Santa Anita Dam. Leaving the foothills the creek continues southwards through Sierra Madre and Arcadia as the Santa Anita Wash, flowing in a concrete channel, it turns southeast towards Azusa south again at Irwindale, where it empties into a small flood control basin.
The water continues out of the basin as the Rio Hondo, which flows southwards to junctions with the San Gabriel River and the Los Angeles River
Whittier Narrows Dam
Whittier Narrows Dam is a 56-foot tall earth dam on the San Gabriel River and the smaller, parallel Rio Hondo. The dam is located, at the Whittier Narrows, it provides water conservation storage and is the central element of the Los Angeles County Drainage Area flood control system. Its reservoir has a capacity of 67,060 acre⋅ft; the Whittier Narrows are a natural gap in the hills that form the southern boundary of the San Gabriel Valley of Southern California. Both the Rio Hondo, a tributary of the Los Angeles River, the San Gabriel River flow through this gap and are impounded by the reservoir; the Pomona Freeway passes through the reservoir flood control basin and the San Gabriel River Freeway passes along the eastern boundary of the basin. In September 2017, the United States Army Corps of Engineers officials warned local residents that the dam no longer met the agency’s'tolerable-risk' guidelines and could fail in the event of a large rare storm, similar to exceptionally intense California storms which occurred between December 1861 and January 1862, a so-called ARkStorm Authorization for the project construction is contained in the Flood Control Act of 18 August 1941 and the initial funds for construction were provided in the 1949 Appropriations Bill.
The U. S. Army Corps of Engineers completed construction of the dam in 1957; the purpose of the project is to collect runoff from the uncontrolled drainage areas upstream along with releases into the San Gabriel River from the Santa Fe Dam. The Rio Hondo outlet has four main outlet passages plus a small diversion passage; the San Gabriel outlet has nine large gates installed on top of a spillway. Dimensions are furnished in the table below; the "stand-by" position of the gates on the Rio Hondo outlet is wide open. On the San Gabriel side one gate is open about.5 ft with the remaining gates closed. The reservoir is empty, a "crossover weir" within the reservoir keeps the flows from the Rio Hondo and the San Gabriel River separated; the natural flow to each river therefore passes through the dam unhindered. During the initial stages of a flood event, the gates on the Rio Hondo side are closed to build a water conservation pool; as long as the pool on the Rio Hondo side of the reservoir is below elevation 201.6 ft NGVD29, releases are made to accommodate the capacity of the spreading grounds downstream along the Rio Hondo.
The spreading grounds are operated by the Los Angeles County Department of Public Works to recharge the groundwater basin. Flow reaches the spreading grounds either directly by way of the diversion passage or from a diversion structure in the Rio Hondo downstream of the dam. Both the diversion passage direct from the dam and the diversion structure in the Rio Hondo are operated by the county; when the water conservation pool on the Rio Hondo side of the reservoir is exceeded, the releases to the Rio Hondo are increased to match inflow until either the capacity of the Rio Hondo or the Los Angeles River downstream are reached. If the water conservation pool on either side of the reservoir is exceeded, discharges on the San Gabriel side can be increased to 5000 ft³/s; the San Gabriel outlet has automatic spillway gates. When the pool in the reservoir exceeds flood control storage these gates will begin to open automatically; the top of the flood control storage pool is at elevation 228.5 ft NGVD.
The capacity of the Rio Hondo downstream from Whittier Narrows Dam is 36,500 ft³/s. The capacity of the Los Angeles River downstream of its confluence with the Rio Hondo is 127,000 ft³/s, the capacity of the San Gabriel River downstream of the dam is 13,000 ft³/s. List of dams and reservoirs in California Whittier Narrows "Whittier Narrows Dam". Army Corps of Engineers
Castaic Dam is an embankment dam in northern Los Angeles County, near the unincorporated area of Castaic. Although located on Castaic Creek, a major tributary of the Santa Clara River, Castaic Creek provides little of its water; the lake is the terminus of the West Branch of the California Aqueduct, part of the State Water Project. The dam was built by the California Department of Water Resources and construction was completed in 1973; the lake has a capacity of 325,000 acre feet and stores drinking water for the western portion of the Greater Los Angeles Area. Castaic is an earth-fill dam with its surfaces covered with boulders and cobble-sized rocks to prevent erosion; the dam is 340 feet high above the streambed, 425 feet above the foundations, 5,200 feet long, containing 44 million cubic yards of material. The maximum thickness of the base is 2,350 feet. Flood waters are released through an ungated, concrete overflow spillway on the west side of the dam, emptying into a stilling basin called Castaic Lagoon.
The total storage capacity of Castaic Lake is 325,000 acre⋅ft, of which 31,000 acre feet is considered active capacity and 294,000 acre feet are considered inactive. The inactive capacity is only used during periods of extended drought or interrupted water delivery, most in 2014. At maximum water elevation of 1,515 ft AMSL, the lake covers 2,235 acres, with 29 miles of shoreline; the much smaller Castaic Lagoon covers 200 acres. Castaic Lake is the lower and larger of two main storage reservoirs for the West Branch of the California Aqueduct. Water drawn from the Sacramento–San Joaquin River Delta is transported down the San Joaquin Valley via the California Aqueduct and pumped over the Tehachapi Mountains, where it splits into the East Branch – providing water for Riverside and San Bernardino and eastern Los Angeles Counties – and the West Branch, which supplies western Los Angeles and parts of Ventura County; the West Branch first enters Pyramid Lake, formed by Pyramid Dam, before traveling through the 7.2-mile Angeles Tunnel to the upper end of Castaic Lake.
Together, the two reservoirs can store about a year's supply of water. During normal operations, Castaic Lake serves as a regulatory reservoir for water delivered through the California Aqueduct, releasing it at times of peak demand. However, the dam and lake was built to provide a pool of "emergency storage" that can be drawn down if water deliveries from northern California are interrupted, whether due to construction, equipment malfunction or severe drought. Below the dam, the majority of the water flows to Los Angeles via a system known as the Foothill Feeder, operated by the Metropolitan Water District of Southern California; the water travels about 20 miles south via a 16.75-foot diameter pipeline to the Jensen Filtration Plant near San Fernando, where it connects to the municipal water system. The underground, pre-stressed concrete pipe has walls nearly 4 feet thick. Water from the Foothill Feeder is stored in the smaller Los Angeles Reservoir in the San Fernando Valley; the water continues south via the 45-mile Sepulveda Feeder, which provides water to Los Angeles proper and other municipalities in south Los Angeles and Orange Counties.
The main customer water agencies are the Central Basin Municipal Water District, West Basin Municipal District, Municipal Water District of Orange County. As many as 12 million people in these areas receive their full or supplemental water supply from Castaic Lake and the feeder system. A smaller portion of the water supply is distributed by the Castaic Lake Water Agency; the service area covers about 195 square miles in Ventura and north Los Angeles counties, providing water to about 287,000 people. The main constituents of the agency include the Los Angeles County Waterworks District No. 36, Newhall County Water District, Santa Clara Water Division, Valencia Water Company. The 11 MW Foothill Feeder hydroelectric power plant is located at the base of the dam and generates electricity when water is needed in Los Angeles. In 2009, the Foothill Feeder plant generated 49 million kilowatt hours; the 1,495 MW Castaic Pumped-Storage Plant is located at the upper end of the west arm of Castaic Lake. The Elderberry Forebay Dam separates the upper arm from the rest of Castaic Lake, maintaining a small pool for power generation known as the Elderberry Forebay, serving as the lower reservoir of the pumped-storage operation.
Pyramid Lake, located 7.2 miles to the west, serves as the upper. When demand for electricity is high during the afternoon, water is withdrawn from Pyramid Lake and released into Castaic Lake. At night, when demand is low, water is pumped back into Pyramid Lake; the sale of peak electricity reduces the Department of Water Resources' overall electric costs for operating the California Aqueduct. In 2009, the Castaic pumped-storage plant generated a net 465 million KWh. List of dams and reservoirs in California List of power stations in California List of the tallest dams in the United States "Castaic Lake Dam". Geographic Names Information System. United States Geological Survey. "Dams Within the Jurisdiction of the State of California". California Department of Water Resources, Division of Safety of Dams. Archived from the original on 2012-03-09. Retrieved December 3, 2012
The Sepulveda Dam is a project of the U. S. Army Corps of Engineers designed to withhold winter flood waters along the Los Angeles River. Completed in 1941, at a cost of $6,650,561, it is located south of center in the San Fernando Valley eight miles east of the river's source in the western end of the Valley, in Los Angeles, California. Sepulveda Dam, along with Hansen Dam located in the north San Fernando Valley, was constructed in response to the historic 1938 floods which killed 144 people. Sepulveda Dam was placed at what was at the current edge of the city. East of the dam the river was crowded into a narrow bottom by the city's growth. One legacy of Sepulveda Dam is its flood control basin, a large and undeveloped area in the center of the Valley, used for wildlife refuge and recreation, but another legacy of the 1938 Los Angeles River flood was the post-World War II channelization of all the Valley's dry washes, which along with the post-World War II rapid suburbanization left the Valley with hot, concrete-lined river bottoms instead of greenbelts.
Although now, in part, these are being devolved as interconnecting bike paths. Behind the dam, the Sepulveda Basin is home to several large recreation areas including Woodley Park, a model aircraft field, The Japanese Garden, a wildlife refuge, a water reclamation plant, an armory; the Basin is kept free of urban over-building so that water can build up there during a prospective hundred-year flood. It is an often-used location for car commercials; when the 1914 flood caused $10 million in damages to the developing basin areas, a public outcry began for action to address the recurring flooding problems. During the following year, the Los Angeles County Flood Control District was formed; some of the early flood control efforts included smaller areas of channelization and the planning for needed reservoirs. Taxpayers approved bond issues in 1924 to build the first major dams. However, they were not willing to provide enough funding for the much needed and substantial infrastructure downstream of these dams.
After two more destructive floods in the 1930s, most notably the 1938 flood, federal assistance was requested. The Army Corps of Engineers took a lead role in channelizing the river and constructing several dams which would create flood control basins behind them. Channelization began in 1938, by 1960, the project was completed to form the present fifty-one mile engineered waterway. Included in this work were Hansen Dam, completed in 1940 and followed by Sepulveda Dam in 1941. In 1973, Burbank Blvd was built through the Sepulveda Basin, Woodley Ave was built in the recreation area in 1975. For 28 years the Sepulveda Dam did its job without incident until 1969 when the Los Angeles River overflowed its banks causing millions of dollars in damage. In 1988 the Los Angeles River's banks were raised to avoid another incident. In 1994 a hundred-year flood occurred in the Los Angeles River; the dam was restored and went without incident for another 11 years until the Los Angeles River again overflowed its banks in 2005.
During the 2028 Summer Olympics, the area around the dam will host Canoe Slalom and Shooting. The 2,000-acre Sepulveda Basin Recreation Area is a flood control basin managed by the Los Angeles City Department of Recreation and Parks. Woodley Park is a large city park located on Woodley Avenue between Burbank Boulevards; the Leo Magnus Cricket Complex, a dog park, group picnic areas are within the park. The park was opened in 1975; the Japanese Garden is a 6.5 acres public Japanese garden located on the grounds of the Tillman Water Reclamation Plant adjacent to Woodley Park. Lake Balboa Park known as Anthony C. Beilenson Park, is water recreation facility with boat rentals and fishing. Lake Balboa is a 27 acres lake filled with water reclaimed from the Tillman Water Reclamation Plant, it has barbecue pits, children's play area, picnic tables, covered picnic pavilions. There are many Flowering cherry trees in the park; the Sepulveda Basin Wildlife Reserve is at the southeast end of the Sepulveda Flood Control Basin and Recreation Area.
It has two sections, the North Reserve and South Reserve, located north and south of Burbank Boulevard. Both have nature paths and hiking trails. Access and parking are in eastern Woodley Park near to the Tillman Water Reclamation Plant, or from Burbank Boulevard east of Woodley Avenue. Haskell Creek flows through the nature preserve, there are several wildlife ponds. Over 200 species of birds have been seen in the basin. Many, attracted by the water, gather here during spring migrations; the Sepulveda Basin Wildlife Reserve is an ongoing habitat restoration project, with locally native California plants. Native trees include Fremont's cottonwood, Coast live oak, Valley oak, California Black Walnut, California sycamore; the Sepulveda Dam Recreation Area Bike Path is a 9 miles bicycle path route looping around the recreation area. It runs from Victory Boulevard near Interstate 405, westward to White Oak Avenue, south on White Oak to Burbank Boulevard, east on Burbank to Woodley Boulevard, north on Woodley returning to Victory Boulevard.
Public access is continuous along it. A shorter route heads south on Balboa Boulevard, which crosses a natural stretch of the Los Angeles River that lined with native Arroyo willows, California sycamores, other California native plants; the loop sections along Victory and Burbank can be frequented by joggers. The bike path can seasonally have burr-bearing weeds. There is ample free parking available in the public park, sports field
The 100-foot-tall Rindge Dam on Malibu Creek is located in Malibu Creek State Park in the Santa Monica Mountains, about three miles from the Malibu coastline in southern California. Situated just northeast of Malibu Canyon Road, it is visible from the turnouts south of the tunnel; the main concrete arch of the Rindge Dam was completed in 1924. The spillway of the dam was finished in 1926; the dam was built by hired workers of May Knight Rindge, who owned the Malibu Ranch, the former Rancho Topanga Malibu Sequit, at that time. The frame of the dam was constructed out of rails from the Hueneme and Port Los Angeles Railway, a 15-mile railroad that May Rindge built through the Malibu Ranch; the dual walls of the dam were built into an already-existing rock monolith in the center of Malibu Creek. The 600 acres behind the dam have been filled with sediment since around 1950, which creates a waterfall from Malibu Creek; the dam became incorporated into Malibu Creek State Park in 1976. Fish advocates have called for the dam's removal because it is blocking Steelhead trout from accessing the upper reaches of the Malibu Creek watershed.
Others have campaigned in vain for the designation of the Rindge Dam as a California Historical Landmark. The Rindge Dam is property of the California Department of Parks and Recreation and the structure has been in disrepair for decades; the dam was declared off-limits to the public in 2014. The dam will be removed, but no conclusive decision has been made yet. Estimates for the cost of demolition have been as high as $80 million. There has been much speculation as to what would happen if the Rindge Dam were removed or collapsed, to where its remnants and over 85 years of impounded sediment would go; the 1947 Matilija Dam, in the Los Padres National Forest north of Ojai blocks steelhead trout spawning grounds and is planned for removal. Designed for water storage and flood control on Matilija Creek, it no longer performs either since it has silted up. Adamson House Frederick H. Rindge List of dams and reservoirs in California Malibou Lake Malibu Creek State Park Sherwood Dam Hueneme and Port Los Angeles Railway
Eaton Canyon is a major canyon beginning at the Eaton Saddle near Mount Markham and San Gabriel Peak in the San Gabriel Mountains in the Angeles National Forest, United States. Its drainage flows into the Rio Hondo river and into the Los Angeles River, it is named after Judge Benjamin S. Eaton, who lived in the Fair Oaks Ranch House in 1865 not far from Eaton Creek; the most well-known portion of the canyon is the Eaton Canyon Nature Center in California. The trailhead of the Mount Wilson Toll Road is in the canyon. Eaton Canyon is in the foothills of the San Gabriel Mountains. Called "El Precipicio" by the Spanish settlers because of its steep gorges, the canyon falls under several governmental jurisdictions. Benjamin Eaton was hired by Don Benito Wilson to bring water to the Fair Oaks Ranch. In August 1877, naturalist John Muir set out from Pasadena for an expedition into the San Gabriels, he writes: "On the first day of my excursion I went only as far as the mouth of Eaton Canyon, because the heat was oppressive, a pair of new shoes were chafing my feet to such an extent that walking began to be painful."On October 27, 1993, the floor of Eaton Canyon, along with 118 surrounding homes, was devastated by a wildfire.
The Eaton Canyon Natural Area Park is located where the mountain stream debouches into the foothill wash at the base of the San Gabriel Mountains. The park is administered by the Los Angeles County Department of Recreation; the county administers the lower two-thirds of the area below the toll road bridge. Most of the 190 acres that comprises the natural area lie on the northern boundaries of the old Rancho San Pascual and Rancho Santa Anita on land designated for the Southern Pacific Railroad. Once the railroad gave up the land, it was opened for homesteading; the nature center is unique in the area because it houses exhibits that educate on the flora and fauna local to the San Gabriel Valley Southern California. The center was rebuilt in 1998. Pasadena and parts of Altadena receive about 40% of their water from local sources; the upper third is controlled by the Water Department of the City of Pasadena. 34.177233°N 118.097°W / 34.177233. John Muir once described the waterfall as "a charming little thing, with a low, sweet voice, singing like a bird, as it pours from a notch in a short ledge, some thirty or forty feet into a round mirror-pool."Several waterfalls exist above Eaton Fall, which are more secluded.
Until 1979, there was a tunnel which allowed access. While the upper falls were accessible decades ago, there are no longer any maintained trails. People have been killed trying to make these climbs. On July 31, 2011, a man fell to his death on the hike to the falls. Another man fell to his death one week on August 6, 2011. On March 22, 2013, two hikers tried to climb to the second waterfall, but decided against it mid-climb; as they made their way down, they both fell. One hiker, a high school senior, fell to her death, the other was airlifted for treatment. On June 27, 2014, the US Forest Service announced plans to close the trail to the upper falls; the trail to the upper falls was closed off on August 1, 2014. Violators caught trespassing the off-limits area will face a fine of up to $5,000 or six months in jail. 34.1966°N 118.1028°W / 34.1966. It is administered by the Los Angeles County Department of Parks and Recreation and has been open since 1962, it was planned as an eighteen-hole facility and was designed by famed golf course architect, William Francis Bell.
Opening day ceremonies included a golf outing with dignitaries and local golf professionals, including 1961 PGA Champion, Jerry Barber. 34.1658°N 118.1044°W / 34.1658. It was accessible from Pasadena via Santa Anita Avenue which drove right to the front porch of the toll house; the road is still accessible from Pinecrest Drive, just off Altadena Drive in Altadena. Access was blocked after a 2005 landslide destroyed 50 yards of the road, but the road has since been rebuilt and reopened. Mount Wilson had always been active with human passage starting from the days of the local Indians, it was Benjamin Davis Wilson who established a proper trail to the summit of Mt. Wilson from Sierra Madre through the Santa Anita Canyon; the Mt. Wilson Toll Road to Henninger Flats is controlled by the Forester and Fire Warden of the Los Angeles County Fire Department. 34.19189°N 118.1044°W / 34.19189. The wash is one of the Altadena streams. Rubio, Las Flores and others all flow to the east to join the Rio Hondo.
Millard Canyon on the west flows to the Arroyo Seco. Eaton Wash is one of the two major streams. On its way to the Rio Hondo, the Eaton Wash is joined by the combined drainages from Pasa