The case for re-using sediment from the Tuyamuyun Hydropower Complex
Time frame: August 2022 - March 2023
Due to significant sedimentation of the Tuyamuyun Hydropower Complex on the lower Amu Darya River, bordering Uzbekistan and Turkmenistan, Altus Impact was contracted to find economically viable solutions to manage reservoir sedimentation, by applying a Water-Energy-Food Nexus approach.
The study was undertaken as part of the second phase (2020-2023) of the European Union project "Central Asian Dialogue to Promote Sectoral Financing through the Water-Energy-Food Nexus", which is being implemented by the Regional Environmental Centre for Central Asia (CAREC). The project is a part of the global Nexus Dialogue Programme, which is supported by the European Union (EU) and the German Federal Ministry for Economic Cooperation and Development (BMZ).
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. Such design defers future sediment management to another generation than those that built the dam (Randle and Boyd 2018).
Today, 40 years after its construction, the THC is suffering from significant sedimentation and will cease to function within 20 years if no further action is taken, thus compromising water, energy and food security of the region. At the same time, there is an imminent supply crisis of sediment materials, especially sand, referred to as the unrecognized hero of our development, used for roads, buildings, infrastructure, land reclamation, electronics, and more. There is consequently an important opportunity to capitalise on reservoir sediments, for the construction industry whilst improving reservoir storage, relative to the situation’ of continued sedimentation.
Maintenance dredging is a requirement for minimising disaster risks and maintaining hydropower capacity and should start as soon as possible (Siri 2022). The financial feasibility assessment produced by Altus Impact, shows that the potential gross profit from sediment re-use during a maintenance dredging phase is in the order of EUR 4.6 million per annum, which is sufficient to cover the estimated dredging and sediment management costs of EUR 4.4 million per annum. As such,the bankable component of sediment re-use can be used co-finance the preservation of the Hydropower Complex.
The experience that is gained through the maintenance dredging campaign, can serve as a pilot for a much larger reservoir storage recovery program that would help safeguard water, energy and food security, disaster risk resilience and provide a sustainably supply of raw materials for the construction industry within the Amu Darya watershed.
Moreover, by ensuring adequate pricing of key THC reservoir services – especially, irrigation water and electricity – the effective operation and maintenance of the THC may also be secured in time. There is ample scope to start cost-recovery efforts and develop fruitful Public Private Partnerships to turn unwanted sediments into economic resources. Through the lens of a Water-Energy, Food & Construction (WEFC) nexus, viable financing options for the recovery of those resources and the protection of the THC have now become visible and actionable.
Presentation: The case for re-using sediment from the Tuyamuyun Hydropower Complex can be downloaded here
Publication: The economic case for re-using sediment from the Tuyamuyun Hydropower Complex can be downloaded here
Meeting of the Technical Working Group (TWG): EUROPEAN UNION SUPPORTS WATER RESERVOIR SEDIMENTATION TREATMENT EFFORTS IN CENTRAL ASIA.
The Seventh EU-Central Asia High Level Conference in Rome: Investment needs and opportunities for the Water-Energy-Food (WEF) Nexus projects
“The reservoir sedimentation at the Tuyamuyun Hydropower Complex has resulted not only in a huge storage loss, but also in a high risk associated with flood passage and infrastructural safety. This problem needs to be addressed urgently,” Dr Sanjay Giri, river and reservoir sediment management specialist from «Deltares» at the 6th meeting of the Technical Working Group, Central Asia, October 26th 2022.
“Materials for construction are becoming increasingly scarce and there is an imminent supply crisis of sand. In the context of a booming construction industry in Uzbekistan, the clean uncontaminated sediments that may be dredged from the THC offer a promising opportunity to supply valuable materials to construction industry, whilst helping safeguard water, energy and food security”, Dr. Vanja Westerberg, Environmental Economist from Altus Impact at the 6th meeting of the Technical Working Group, Central Asia, October 26th 2022.