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25-07-2014, 12:08

Saroj Kumar Jha on Dam Heights, Its Fillability and Rogun Financing

 

Avesta.Tj | 25.07.2014 | World Bank Regional Director for Central Asia Saroj Kumar Jha gave interview on the Rogun Assessment Studies and Consultation Process, which has been posted July 21 on the WB website.


Saroj Kumar Jha said that three possible dam heights were studied (1290 m, 1255m, and 1220m) in Techno-Economic Assessment Study (TEAS).


According to him, the draft consultants’ report concludes that the 1290m design option yields the highest total system cost savings and the highest net present value, meaning that the proposed Rogun project is a lower cost option when compared to any of the alternatives to meeting Tajikistan’s energy needs.


"The relatively shorter lifespan (due to sedimentation) and the lack of downstream flood protection associated with the 1220m option are arguments against the 1220m option. However, the trade-offs between the 1290m and 1255m design options could be explored further. From a dam safety and engineering perspective, the draft studies find no major differences in risks among the different dam height options. The study notes that several of the underground structures, including the two existing diversion tunnels and the powerhouse cavern, would require strengthening and remedial measures, as well as comprehensive monitoring, in order to meet international norms”, added WB representative.


The Regional Director underlined: "In the Environmental and Social Impact Assessment (ESIA), the consultants conclude that there are two important environmental and social issues that would need to be addressed in detail: (a) resettlement of households living near the dam site and in the reservoir area, and (b) potential reductions in summer flows, which could negatively affect downstream irrigation. The ESIA identified measures to mitigate the impacts of involuntary resettlement and the current estimate of the costs of resettlement is included in the economic and financial analyses for each of the three dam design options.


Regarding downstream flows, the draft ESIA notes that a dam at the Rogun site could impact flows in two ways: how it is filled and how it is operated. Tajikistan has not used its full water allocation as set in regional annual allocation decisions but has indicated that it intends to use the full allocation in the future, with difference between its full allocation and its actual use to date averaging 1.2 bcm annually for 2005-11. Using full allocation would reduce downstream flows. If a dam were built at the Rogun site, Tajikistan has indicated that it would use its full allocation to fill the resulting reservoir and subsequently for irrigation.


Regarding dam operation, the draft studies by the consultants confirm that Rogun could be operated in a way that maintains historical flows. The Nurek reservoir is currently used to transfer 4.2 bcm of water from summer (April-September) to winter (October-March) release and maintenance of historical flows is defined in the studies as limiting the summer to winter transfer to this amount. Given the interest of downstream riparians to maintain present seasonal flows in the future, the Government of Tajikistan has indicated that it would operate any future dam at the Rogun site so that the same amount of water is transferred from summer to winter release as is currently done at Nurek, hence the draft studies note that there would be no change in flow pattern from summer to winter. ESIA Panel of Experts is recommending strengthening of existing water allocation arrangements with other riparians to ensure that filling and operation regime are implemented as proposed by the Government of Tajikistan.”


According to the draft consultants’ reports and the independent Panels of Experts, it is feasible to build and operate a dam at the Rogun site within modern international norms but contingent on incorporating the experts’ recommendations on modifying the original design, implementing the mitigation measures, and establishing monitoring systems throughout the life of any future project. However, the feasibility of actual construction and the realization of estimated benefits would depend on the availability and terms of financing and the institutional arrangements for its construction, filling, and operation as observed in the "World Bank Draft for Discussion: Key Issues for Consideration on the Proposed Rogun Hydropower Project”.


Talking about financial side Saroj Kumar Jha noted: "World Bank financing for the Assessment Studies and consultation process does not imply that the Bank would finance construction of Rogun in the future.


However, we remain a committed development partner in Tajikistan and Central Asia. We will continue to encourage a riparian dialogue about sustainably managing the Central Asia region’s energy and water challenges in a mutually beneficial manner.” 





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