Although a subsurface dam enjoys many advantages, their replacement with conventional ones is not feasible, the deputy energy minister said.
"Underground dams have unique advantages, including low evaporation rate, being eco-friendly and not causing a human disaster in case of collapse. Nevertheless, it is not always possible to replace them with surface dams as each of these structures have their own pros and cons," Rahim Meidani added, ISNA reported.
Referring to Khouzestan Province in southern Iran as a case in point, the official said, "There are no water tables in this region as a result of which surface water cannot be stored. Thus, subsurface dams can play a major role in conserving water in this region."
Meidani stressed that nowhere in the world these dams have been substituted with each other.
"Water crisis in Iran ought to be addressed via other solutions, one of which is building conventional dams based on modern international standards," he said.
Highlighting the lack of feasibility studies to construct underground dams, Rahimi said, "It is practically impossible to build a subsurface dam for 48 billion cubic meters of water."
Asked about the desirability of constructing dams the country is experiencing its worst drought, he said, "If it were not for embankment dams, the crisis would have been much worse.
"Had the dams around Tehran not been built, supplying the city dwellers in Tehran with potable water would have posed a big challenge. Hence, questioning the practicality of conventional dams is not justifiable."
Geographically speaking, 75 percent of Iran has a dry, arid and semi-arid climate. Iran has a continental type of climate, with cold winters and hot summers across the plateau. On the plateau, the annual rainfall does not exceed 30 centimeters (12 inches), while deserts and the Persian Gulf littoral areas receive less than 13 centimeters (5 inches).
A subsurface dam stores groundwater in the pores of strata and uses groundwater in a sustainable way. In some cases, they are also built to prevent saltwater from intruding into a freshwater aquifer.
Underground dams are typically built in areas where water resources are minimal and need to be efficiently stored, such as in deserts and on islands like the Fukuzato Dam in Okinawa, Japan. They are most common in arid areas of Brazil while also being used in southwestern United States, Mexico, India, Germany, Italy, Greece and France.
