Hydroelectric Dam Failures – Fujinuma Dam in recent Japan Earthquake

The Fujinuma Dam, also known as the Fujinu Dam, was an embankment dam on a tributary of the Abukuma River 16 km (10 mi) west of the city office of Sukagawa City in Fukushima Prefecture, Japan. The dam failed on 12 March 2011 after the 2011 Tōhoku earthquake. The flood washed away five houses while damaging others, disabling a bridge and blocked roads with debris. Eight people were missing and four bodies were discovered after searches began at dawn. Note: This does not count against deaths per TWH by energy source because it was a dam for irrigation and not for power generation.

On 12 March, 252 dams were inspected and seven dams were found to be damaged. Six embankment dams had shallow cracking on their crests and the reservoir at one concrete gravity dam had a slight slope failure. Four dams, including the Fujinuma, were inaccessible and could not be inspected. When the roads clear, further inspections are expected to take place.

Sydney Morning Herald – a dam used for hydroelectric power in the Fukushima district collapsed, obliterating, according to some reports, 1800 homes.

Delhi Dam in Iowa is supposed to generate power. It had a failure in 2010 and caused an evacuation of 8000 people and millions in property damage

The Kyzyl-Agash Dam failure occurred when a dam located outside the village of Kyzyl-Agash, Almaty Province, Kazakhstan. On 11 March 2010, the dam burst, flooding the village. At least 43 people (possibly 200) were killed, an additional 300 people were injured, and over 1000 evacuated from the village.

Russian dam turbine failure that killed 75

The 2009 Sayano–Shushenskaya hydroelectric power station accident occurred at 17 August 2009 when turbine 2 of the Sayano–Shushenskaya hydroelectric power station broke apart violently. The turbine hall and engine room were flooded, the ceiling of the turbine hall collapsed, 9 of 10 turbines were damaged or destroyed, and 75 people were killed. The entire plant output, totaling 6,400 MW and a significant portion of the supply to the local grid, was lost, leading to widespread power failure in the local area, and forcing all major users such as aluminum smelters to switch to diesel generators.

Penstock (Switzerland) rupture in 2000 Three people were killed in the tragedy.

Lawn Lake and Cascade Dams in Colorado (1982) The flash flood that killed three people camping in the park and caused $31 million in damage.

Kelly Barnes Dam in Georgia 1977 It collapsed on November 6, 1977 after a period of heavy rainfall, and the resulting flood killed 39 people and caused $2.8 million in damages.

Banqiao Dam failure in 1975. Approximately 26,000 people died from flooding and another 145,000 died during subsequent epidemics and famine. In addition, about 5,960,000 buildings collapsed, and 11 million residents were affected. Unofficial estimates of the number of people killed by the disaster have run as high as 230,000 people. The death toll of this disaster was declassified in 2005

Machhu II (Irrigation Scheme / hydroelectric) Dam, Gujarat, India – The dam failed on August 1, 1979, because of abnormal floods and inadequate spillway capacity. Consequent overtopping of the embankment caused a loss of 1800 lives. Other reports indicate that over 2500 people died

Gleno Dam, Italy failed in 1923, killing at least 356 people

German hydroelectroc dams were attacked and breached in 1943.

In terms of deaths: according to the latest sources, at least 1,650 people were killed: around 70 in the Eder Valley, and at least 1,579 bodies were found along the Möhne and Ruhr rivers, with hundreds missing. 1,026 of the bodies found downriver of the Möhne Dam were foreign prisoners of war and forced-labourers in different camps, mainly from the Soviet Union.

Wikipedia has a list of dam failures

Major Non-hydro power dam failures

Malpasset Dam, France 1959 – 421 deaths

Vajont Dam, Italy 1959 – 2000 deaths

The Black Hills Flood of 1972, in the Black Hills of Western South Dakota, USA. the Canyon Lake Dam became clogged with debris and failed, resulting in 238 deaths and 3,057 injuries. Several bodies were never found. There were over 1,335 homes and 5,000 automobiles destroyed.

Machhu dam in western India 1979 – 2500 deaths

St. Francis Dam, California 1928 – 450 deaths