School of Engineering (SEN)

Permanent URI for this community

https://escholar.umt.edu.pk/handle/123456789/3851

Browse

Browsing School of Engineering (SEN) by Author "Aaqib Farooq"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Sediment evacuation from tarbela reservoir
    (UMT.Lahore, 2020) Aaqib Farooq; Abdul Haseeb; Haris Miqdad; Muhammad Saad ul Hassan
    Tarbela is one of the world's largest water resource development projects. The Project is the capstone of the Indus Basin Treaty providing an improved supply of water to irrigated land in Pakistan as well as generating electricity and allow some control of floods. River Indus and its tributaries, namely Shyok, Gilgit, and Hunza carry significant sediments into the Indus river. Most of these incoming sediments are being trapped in the reservoir and deposited in the upper reaches of the reservoir. A part of the sediments escapes from the reservoir through the outlets while a huge amount of the sediments gets accumulated as a major delta. At lower sediment loads it is possible to manage these deposits by sluicing through the dam which can be achieved at times of high flows. However, at periods of repeated high flows, as will occur with Tarbela Reservoir flushing, the sand bars build up. In the power channel, the development of these sand bars across the entrance will create problems and result in a head drop. If the Tarbela reservoir is operated to draw more sediment out of the reservoir then turbines of Tarbela will be subject to greater sediment load. The analysis was carried out by HEC-RAS model , it was used to simulate different scenarios for flushing through the Tarbela dam. For this purpose the hydrological data including sediment inflow, outflow, 10 daily discharges from 1979 to 2017 was collected from WAPDA. The simulated and actual profiles in terms of sediment deposition, sediment outflow, and remaining capacity was calibrated and validated for the years 2009 and 2012 respectively. The longitudinal profiles, which provided an understanding of the rate of advance of the delta, the foresee slopes, and in which areas of the reservoir the incoming sediment is accumulated. The delta is estimated to arrive at the dam by the year 2033 and the sediment outflows start to increase (the average once the delta arrives is 100 MT with less amount of sand). Clearing sediment from around the intakes is unlikely to be of significant value as the area should be cleared more effectively by the sluicing effect of the discharge through the tunnels