The Kajakai Dam is one of the two major hydroelectric power dams of Helmand province in southern Afghanistan, located on the Helmand River. It is located 100 miles (161 km) north-west of Kandahar City. It has a dual function, to provide electricity and to irrigate some 650,000 acres (1800 km²) of an otherwise arid land. Water discharging from the dam traverses some 300 miles (500 km) of downstream irrigation canals feeding farmland. It currently produces 33 megawatts of electricity.
It is 320 feet (100 m) high and 887 feet (270 m) long, with a storage capacity of 973,000 acre-feet (1.2 km³) of water. The dam is the main watershed for the Sistan Basin.
The dam was built in 1953, by the Morrison-Knudsen firm. When the Soviets invaded Afghanistan, the contractors left. They intended to raise the dam by 2 meters in order to increase the available water for power production and irrigation. They were also cutting in an emergency spillway, which was never completed. Gates were also never installed in the service spillway so the dam passes all water in the reservoir above elevation 1033.5 meters.
Under an accord signed between Iran and Afghanistan in 1972, Afghanistan is obliged to release at least 910 cubic feet (26 m³) of water a second. Taliban briefly stopped the flow of water to Iran when the latter threatened to attack in retaliation for the killing of Iranians whom were claimed to be diplomats in Mazari Sharif when the Taliban retook the city from the Northern Alliance the second time. During that time Helmand valley was going through a five year drought.
In 1975, USAID commissioned the initial installation of two 16.5 MW generating units in a powerhouse constructed at the toe of the dam. This first stage powerhouse was actually constructed to house three equally sized units.
The Kajakai dam powerhouse was a bombing target by the US Air Force during their attack on Afghanistan in October 2001.
With help from USAID, Unit 1 has been fully rehabilitated and currently produces 16.5 MW of reliable power. The Unit 3 rehabilitation began in May 2006, with a scheduled return to service in early 2007. The new 18.5 MW Unit 2 turbine/generator has been contracted to China Machine Building International Corporation, which is headquartered in Beijing. Engineering, design and procurement are ongoing. The work will be supervised by Montgomery Watson Harza and is planned to be completed by June 2007. Central to the long term energy security and sustained economic growth of south-eastern Afghanistan is the rehabilitation and expansion of the Kajakai HPP. As a critical component of the South East Transmission System, the capacity of the Kajakai HPP will be expanded to 51 MW with a future potential for an additional 100 MW.
As a result, Iran's famous Hamoun lake dried up as did other regional pastures, leading to the death of flora, fauna, cattle and birds in the Sistan and Baluchistan province of Iran.
In February 2007, the Kajakai Dam was the subject of fighting between NATO and Taliban insurgents, as part of the so-called Operation Kryptonite. According to Helmand governor, Assadullah Wafa, over 700 Taliban insurgents (including Pakistanis, Chechens and Uzbeks) coming from neighbouring Pakistan fought against over 300 NATO troops. Most of the NATO troops were Dutch and British. The number of casualties mentioned varies. The Taliban intend to destroy the dam.
In late August 2008 a contingent of British, Afghan and ISAF troops successfully transported the third turbine from Kandahar Airbase in Kandahar Province to the Kajakai Dam. When the turbine comes online, and when a new grid of power lines are established to distribute the power, it is expected that the dam will be able to provide 51 megawatts of power. The operation was British led and codenamed Operation Oqab Tsuka, meaning "Eagle's Summit" in Pashtu. Despite the turbine being delivered, as of December 2009, it has not been installed as its installation will require 900 tonnes of cement which cannot be delivered to the dam due to attacks by the Taliban.