Sedimentation is reducing the capacity of the Nurek reservoir in Tajikistan, threatening the long term viability of a nationally important hydropower operation.
HR Wallingford is leading a project to analyse, map and model the scale of the sedimentation, in order to help the national power company, Barqi Tojik, develop their long term management strategy for the reservoir. The work will help to maximise the life of the power station and secure its effective operation for the long term.
The 300 metre tall Nurek dam on Tajikistan’s Vakhsh river is the second tallest dam in the world. Built during the 1960s, the dam impounds a 70 km long reservoir with a capacity some fifty times greater than the largest reservoir found in the UK. The hydropower station at Nurek uses water from the reservoir to generate enough power to satisfy 98 per cent of Tajikistan’s annual energy requirements.
Sedimentation in the reservoir has significantly reduced its capacity and, without intervention, has the potential to reduce or stop energy production entirely. The continued effective operation of the Nurek facility is critical to ensure the country’s power demands are met.
HR Wallingford is leading a World Bank funded project to help Tajikistan develop effective management strategies for Nurek reservoir. Titan Environmental Surveys and Wallingford Environmental Surveys will help HR Wallingford establish the current capacity of the Nurek reservoir using bathymetric surveys, sediment sampling and onsite laboratory analysis. These data will be used to produce a detailed 3D map of the reservoir bed and to provide a detailed understanding of the level and type of sedimentation.
HR Wallingford will use the survey data to build a detailed numerical model of the reservoir system in RESASS, their specialist sedimentation modelling software. RESASS can simulate long term deposition patterns in a reservoir and predict the effect of various different intervention techniques on reservoir storage capacity.
The understanding developed on this project will also be invaluable to the Tajikistan government in their operation of the new Rogun dam, a new 330 metre tall dam currently under construction upstream of Nurek.