Hydraulic model studies for the Ghazi-Barotha hydropower project, Pakistan

Abstract

The $2200 million Ghazi-Barotha hydro-power project—one of the largest currently under construction worldwide and expected to be completed in about 2002—will have a peak generating capacity of 1450 MW and provide an estimated annual energy output of 6600 GWh. Its main components are a gated barrage and flow diversion structure on the Indus River at Ghazi, about 7 km downstream of Tarbela dam a 52 km long power channel with a discharge capacity of 1600 m3/s, bypassing a relatively steep reach of river, including Attock Gorge a five-unit powerhouse, discharging back to the Indus at Barotha via a 2 km long tailrace an ‘emergency’ spillway providing a bypass to the powerhouse two ‘headponds’ upstream of the power intake, to provide sufficient daily storage to support diurnal ‘peaking’ of the units. The project has a number of interesting hydraulic features, many of which were developed with the aid of about a dozen physical model studies. This paper includes a brief description of the project, outlining the role of most of the model studies and then describes two of them in greater depth.