To meet the requirements of irrigation in Malakand valley and district Mardan and Swabi, an irrigation scheme was planned by the British Government in 1903. The plan consists of headwork at Amandara near Batkhela on River upper Swat, unlined irrigation channel 7.2 Km long up to Malakand Pass and excavation of 17.5 Ft dia, 3.4 Km long tunnel underneath of Malakand Pass. A network of irrigation canals including Abazi and Machai branches and their distributaries were also part of the project. The project started in 1907 and completed in 1914.
In 1930, a hydropower project was planned by British Government, at Jabban, 10 Km of Dargai town Malakand Agency. For this purpose a free power tunnel called Barkat tunnel was excavated on the right side of the outlet regulator of Benton tunnel. The length of tunnel is 0.97 Km and its diameter is about 14 feet. The discharge capacity of Barkit tunnel is 1200 cusecs. Jabban hydro power projects was started in 1934 and completed in 1937.
After successful commissioning and operation of Jabban Power Station, an idea was proposed that if the water from the Tail Race of Jabban Power Station is led to Dargai, sufficient head could be produced large enough to produce electric power of 20 MW. To give practical shape to this idea, in 1948 another power projects was planned at Dargai Malakand Agency which completed in 1952.