Publication // Meeting the demands of the construction industry – The economic case for re-using sediment from the Tuyamuyun Hydropower Complex
By Dr. Vanja Westerberg. The Tuyamuyun Hydro Complex (THC) is a system of four interconnected reservoirs and a series of canals on the lower Amu Darya River, bordering Uzbekistan and Turkmenistan. After having been in operation for 40 years, the sediment management problem at the THC is very real. To assess the economic case for using dredged sediments from the THC, a profit and loss (P&L) account has been established.
Background and Objective
The Tuyamuyun Hydro Complex (THC) is a system of four interconnected reservoirs and a series of canals on the lower Amu Darya River, bordering Uzbekistan and Turkmenistan. Its primary purpose is to provide water for irrigation schemes in Uzbekistan and Turkmenistan. The complex also provides water for industrial and municipal uses and has a 150 MW power station.
Reservoirs, including the THC, are typically built with a design life of fifty years – the time it takes to pay-off capital equipment costs. As a result, sedimentation volume is estimated over this period, and the lowest dam outlets are set above the dead storage, so as to not infringe on active storage during that period. Without consideration to sediment management costs, this kind of design defers future sediment management to another generation than those that built the dam (Randle and Boyd 2018).
The construction of the THC was completed 40 years ago in 1983 and today, the sediment management problem is very real. With 1.5 billion m3 of sediments trapped in the main channel (Ruslovoe) reservoir, the total storage loss is estimated at 63% of total initial storage volume. Projections in Ikramova (2021) suggest that the Ruslovoe reservoir will be entirely lost by 2040 with no further action, whilst the hydropower facility will cease to operate much earlier (Giri 2022b, personal communications).
From an economic perspective, sediments in reservoirs be considered as resources that are ‘out of place’. Whilst effectively reducing the life-span of dams, they are needed to maintain
downstream river ecology and morphology system. Moreover, sediment can have many productive uses. Sand and gravel for example are used to make concrete and asphalt, and are therefore essential for building roads, bridges, hospitals, infrastructure and housing. As such, they are essential resources to economic development.
To assess the economic case for using dredged sediments from the THC, a profit and loss (P&L) account has been established.
Meeting the demands of the construction industry – The economic case for re-using sediment from the Tuyamuyun Hydropower Complex
This publication is also available in Russian.
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