The World Bank released summaries of the first two studies in a series of long-awaited reports on Tajikistan’s controversial Rogun hydropower dam this week. Prepared by French consultancy Coyne et Bellier, the technical assessments are designed to help Tajikistan make informed engineering decisions about the complicated project.
Depending on how you read the carefully worded reports, which have been reviewed by Tajik officials, they could be seen as a victory for either Tajikistan or downstream Uzbekistan. Uzbekistan is vehemently opposed to the project, arguing that it is not safe and that it will give Tajikistan unfair control over water resources. President Islam Karimov has even said that such a project could lead to war.
Yet the reports also allow Tajik officials to argue that everything is under control, that the consultants outlined necessary, but manageable repairs.
For certain, the reports recommend what sounds like a lot of repairs to previously built structures, and expensive-sounding mitigation efforts to address an underground threat.
The 3.6-gigawatt Rogun project was begun in 1976 and stalled after the collapse of the Soviet Union. Tajikistan’s leaders see the dam – at a proposed 335 meters, it would be the tallest in the world – as a source of national pride and have been working on it again in fits and starts for the last few years. The World Bank is expected to offer several alternatives this autumn – three different heights and three different capacities. But it often seems President Emomali Rakhmon has an obsession with breaking records. And there are worries that Tajikistan does not have the technical expertise to build the dam after so many of its educated citizens fled, first war and then two decades of economic malaise that continues with no end in sight.
One of the reports offers some advice on the overall safety of existing structures at the construction site. It notes that many of the tunnels need repairs, that old machines “will be subject to frequent breakdowns, and will consequently limit the production of the batching plants,” and that “concrete production facilities need to be significantly upgraded.” The study singles out the underground “powerhouse cavern” where “[s]ignificant walls deformations have been recorded”:
The strains and deformations distribution shows the critical stability conditions of the cavern complex. This requires additional reinforcement and stabilization measures before any further deepening of the excavation in the powerhouse cavern can be undertaken safely.
The report does not specify what its detailed remediation proposals will cost. It is still unclear who would finance Rogun, which some estimates put at nearly 100 percent of GDP. The World Bank has regularly pointed out that it is not promising funding, but is helping “establish objective, independent, and comprehensive facts for all stakeholders.”
The other report discusses what the World Bank calls a “critical decision point in the overall Rogun Assessment Study process.” A thick “wedge of salt” is sitting in a fault line under the project. If it dissolves, it could create a hollow directly beneath the dam. From that report:
Under the effect of orogenic forces (i.e. the folding and faulting of the earth’s crust), the wedge of salt is being extruded along the Ionakhsh Fault at an estimated rate of 2.5 cm per year. In the vicinity of the Vakhsh River, it is being dissolved at a similar rate, resulting in a state of equilibrium. The impoundment of the Rogun reservoir would result in an increase in the hydraulic gradient and this increase, if not mitigated, would result in an increase in the dissolution rate and a possible formation of a cavity.
A cavity under the earth-fill dam “could affect the water retaining function or even dam integrity.”
How hard will it be to mitigate this risk? The report outlines two measures that engineers must implement: “grouting of the cap rock and inserting a hydraulic barrier.” Those will require regular monitoring and maintenance throughout the construction and possibly the life of the dam. Tajikistan’s ability to perform these functions will be factored into the overall dam risk analysis, the report says.
The final reports will include comments from downstream countries and other stakeholders. Russian-language versions of the reports can be found here and here.