Upper Reservoir Seepage Analysis of Azad Dam Pumped Storage Power Station and Selecting the Best Sealing Method

Seepage analysis in the upper reservoir of the Kurdistan Azad pumped storage dam with a volume of 3800000 cubic meter is an important and effective parameter for selecting of the optimized sealing method. More than 60% of the Lugeon test results show very permeable behavior. In order to calculate seepage discharge from the reservoir with no sealing element, analytical and numerical methods are used. Results of the analytical method and finite element numerical method (SEEP/W software) shown the amount of the seepage discharge in steady state flow is equal to 112600 and 11500 m3/day, respectively. Unsteady state numerical method (UDEC software) showed initial seepage discharge about 1700000 m3/day, decreasing to 112400m3/day while approaching to steady state conditions. 3D seepage modeling using Seep3D software shows about 118000 m3/day seepage discharge, means 3% of the total reservoir volume. Analysis show the necessity of sealing in the reservoir. After feasibility study, the geomembrane method was suggested as the best sealing method with the implementation cost of 20 billion Rls.