Hoover Dam is a concrete arch-gravity dam in the Black Canyon of the Colorado River, on the border between the U.S. states of Nevada and Arizona. It was constructed between 1931 and 1936 during the Great Depression and was dedicated on September 30, 1935, by President Franklin D. Roosevelt. Its construction was the result of a massive effort involving thousands of workers, and cost over one hundred lives. It was referred to as Hoover Dam after President Herbert Hoover in bills passed by Congress during its construction, but was named Boulder Dam by the Roosevelt administration. The Hoover Dam name was restored by Congress in 1947.
A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture, and navigability. Hydropower is often used in conjunction with dams to generate electricity. A dam can also be used to collect or store water which can be evenly distributed between locations. Dams generally 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 Three Gorges Dam is a hydroelectric gravity dam that spans the Yangtze River by the town of Sandouping, in Yiling District, Yichang, Hubei province, central China, downstream of the Three Gorges. The Three Gorges Dam has been the world's largest power station in terms of installed capacity (22,500 MW) since 2012. The dam generates an average 95±20 TWh of electricity per year, depending on annual amount of precipitation in the river basin. After the extensive monsoon rainfalls of 2020, the dam's annual production nearly reached 112 TWh, breaking the previous world record of ~103 TWh set by Itaipu Dam in 2016.
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, approximately eight miles east of the river's source in the western end of the Valley, in Los Angeles, California.
A spillway is a structure used to provide the controlled release of water from a dam or levee downstream, typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure that water does not damage parts of the structure not designed to convey water.
The Shinano River, known as the Chikuma River in its upper reaches, is the longest and widest river in Japan and the third largest by basin area. It is located in northeastern Honshu, rising in the Japanese Alps and flowing generally northeast through Nagano and Niigata Prefectures before emptying into the Sea of Japan.
The Kuma River is a river in Kumamoto Prefecture, central Western part of Kyūshū, Japan. It is sometimes referred as Kumagawa River. It is the longest river in Kyushu, with the length of 115 km long and has a drainage area of 1,880 km2 (730 sq mi). The tidal flat of the Kuma River estuary is approximately 1000 hectares.
Malampuzha Dam is the second largest dam and reservoirs in Kerala, located near Palakkad, in the state of Kerala in South India, built post independence by the then Madras state. Situated in the scenic hills of the Western Ghats in the background it is a combination of a masonry dam with a length of 1,849 metres and an earthen dam with a length of 220 metres making it the longest dam in the state. The dam is 355 feet high and crosses the Malampuzha River, a tributary of Bharathappuzha, Kerala's second longest river. There is a network of two canal systems that serve the dam's reservoir of 42,090 hectares.
The Tokuyama Dam is an embankment dam near Ibigawa, Ibi District, Gifu Prefecture in Japan. The dam was completed in 2008 and will support a 153 MW hydroelectric power station that is expected to be fully operational in 2015. Currently, Unit 1 at 23 MW was commissioned in May 2014. The dam was originally intended to withhold the upper reservoir of a 400 MW pumped-storage power station until a design change in 2004. The dam is also intended for flood control and water supply. It is the largest dam by structural volume in Japan and withholds the country's largest reservoir by volume as well.
The Shō River has its source in Mount Eboshi in the Shōkawa-chō area of Takayama, Gifu Prefecture, Japan. After flowing for 115 km (71 mi) through the northern part of Gifu Prefecture and the western part of Toyama Prefecture, it empties into Toyama Bay.
The Samanala Dam is a dam primarily used for hydroelectric power generation in Sri Lanka. Commissioned in 1992, the Samanalawewa Project is the third-largest hydroelectric scheme in the country, producing 405 GWh of energy annually. It was built with financial support from Japan and the United Kingdom. It is notable for a large leak on its right bank. Power production continues as planned despite the leakage, and the water from the leak now provides two thirds of the water issued by the reservoir for agriculture in downstream areas.
The Upper Kotmale Dam is located in Talawakele, within the Nuwara Eliya District, in the Central Province of Sri Lanka. The dam feeds the third largest hydroelectric power station in the country.
The Gōnokawa River is a river that runs through Hiroshima and Shimane prefectures in Japan. It is the largest river in the Chūgoku region. It is also called the Gōgawa River and, in Hiroshima, the Enokawa River.
Water supply and sanitation in Japan is characterized by numerous achievements and some challenges. The country has achieved universal access to water supply and sanitation; has one of the lowest levels of water distribution losses in the world; regularly exceeds its own strict standards for the quality of drinking water and treated waste water; uses an effective national system of performance benchmarking for water and sanitation utilities; makes extensive use of both advanced and appropriate technologies such as the jōkasō on-site sanitation system; and has pioneered the payment for ecosystem services before the term was even coined internationally. Some of the challenges are a decreasing population, declining investment, fiscal constraints, ageing facilities, an ageing workforce, a fragmentation of service provision among thousands of municipal utilities, and the vulnerability of parts of the country to droughts that are expected to become more frequent due to climate change.
The Shin-Takasegawa Pumped Storage Station (新高瀬川発電所) uses the Takase River to operate a pumped storage hydroelectric scheme about 12 kilometres (7.5 mi) west of Ōmachi in Nagano Prefecture, Japan. Part of the system is within Chūbu-Sangaku National Park.
The Okutadami Dam (奥只見ダム) is a concrete gravity dam on the Tadami River, 26 km (16 mi) east of Uonuma on the border of Niigata and Fukushima Prefectures, Japan. The primary purpose of the dam is hydroelectric power generation and it supports a 560 MW power station which is the largest conventional hydroelectric power station in Japan. The dam also forms the second largest reservoir in Japan, next to that of the Tokuyama Dam.
The Boyabat Dam is a concrete gravity dam on the Kızılırmak River bordering Sinop and Samsun Provinces, Turkey. It is 8 km (5 mi) southwest of Durağan and 24 km (15 mi) southeast of Boyabat. Construction began in 2008 and the dam and power plant were completed in December 2012. Its primary purpose is to generate hydroelectric power. The dam's power plant has an installed capacity of 513 MW.
The Natori River is a river located in central Miyagi prefecture, in the Tōhoku region of northern Japan. It starts at Mount Kamuro in the Ōu Mountains and flows in an easterly direction through the cities of Natori and Sendai. The river's headwaters start in the Zao Mountain range, it flows through the Sendai Plain and ends by draining into Sendai Bay. The river's estuary is located on Japan's east coast, and faces the Pacific Ocean. The river's flow is the greatest during the snow melt season from March to April, the rainy season from June to July and during the typhoon season from September to October. The river's length is 55 km, and its tributaries are the Hirose, Masuda and Goishi Rivers. The Natori provides water for 1 million people in the city of Sendai.
The Kukule Ganga Dam is a 110 m (360 ft) gravity dam built across the Kukule River in Kalawana, Sri Lanka. The run-of-river-type dam feeds an underground hydroelectric power station located approximately 5 kilometres (3.1 mi) away, via tunnel.
