كليدواژه :
Zagros zone , Dye tracer , Leakage , Uncertainty , Karst
چكيده لاتين :
Leakage from dam reservoirs has been reported in different karst regions of the world. In most cases
tremendous additional grout curtains have been constructed to stop or minimize leakage. The practical
solution of leakage is extremely complex and costly. The estimation of leakage is mainly erroneous
due to uncertainties in the non-homogenous nature of a karst formation, the method of study, the
limited investigation due to time and cost limitations, measurement error, and type of flow model. The
qualitative uncertainties in geological features, borehole study, isopotential mapping and dye tracing
are discussed based on the direct experiences of the authors with several dams in Iran. The leakage
uncertainty was calculated for the diffuse and conduit flow models for two strategies of with or
without any grout curtains under the combined effect of input uncertainties such as permeability,
hydraulic gradient, conduit cross section and friction factor in one of the dam sites of Iran, The results
reveal that there are significant uncertainties in conduit flow systems. A big diameter conduit can
convey significant amounts of water under high reservoir pressure heads. The uncertainty may be
decreased if a detailed study is carried out on the stratigraphical and tectonic settings, karst
hydrogeology, geomorphology, speleogenesis, and by performing several dye tracings outside the
proposed grout curtain area.
