The reservoir structures of our homeland are just one of the examples of Iranian architects’ vast knowledge, insight and wisdom. They used innovative methods in the foundation and construction of these buildings so that the structure would remain stable for centuries and its use would be easy for everyone. Remembering and referring to some of those methods will make us more familiar with the storage structures and make the precision in their design more visible. Some of those known innovations are:
The method and how to build a reservoir
First, let us speak about the techniques used by Iranian architects in construction of water reservoirs. To construct a reservoir, first the wall and the foundation of the structure was built and it was allowed to collect rainwater. At this stage the construction was left for 4 years, and only after this long period the reservoir was roofed. To prevent the roof of the reservoir from collapsing, the architects also invented a device called “milak” which was built-in a section of the dome of the structure, so that rain does not stay on the roof and does not cause it to soak and then collapse. Construction of the tank was also very important. Before entering the reservoir, the water that was directed through the aqueducts, was passed through a pond full of sand in order to purify the water from salt and other hard minerals. After going through this pond the water flowed into the tank. All these solutions were formed over the years and as a result of the experience of generations.
Another method was used to prevent water pollution. We know that the reservoir was a place to store water. Stagnant water is a place for the growth of algae and bacteria. The ancients had found a clever solution to prevent the growth of these substances.
By throwing the fish into the reservoir, they kept the water clean and pleasant and prevented it from being polluted. Filling the tank with water was also an important task. This work was done in the cold season of the year. Directing water into the tank started from morning and continued for 3 days. When the minerals in the water settled, and poured into the tank through the vent. This method formed a layer of salt solution on the tank water and prevented the water from decaying.
A few more techniques in construction of reservoirs
– Platforms (or podium) for seniors: Going up and down the many stairs of reservoirs was always challenging for seniors. The Iranian architects built platforms on both sides of the stairs, called “Pirneshin” (seats for seniors). The elderly or the disabled would go up or down a few stairs, sit on these platforms to catch their breath, and then continue climbing or descending.
– Protecting animals: In the Salfi Ewaz reservoir, a city south of Shiraz, at the spot where water is taken, a cut and sharpened stone is placed, which the natives call “bump”. This bump is meant to prevent animals from falling into the water.
– A unique technique in Sardar Bozorg reservoir: the inner walls of Sardar Bozorg Reservoir in Qazvin are slightly uneven. This was to make the water move and prevent it from stagnating. On the other hand, the structure of the Sardar Bozorg reservoir has been strengthened so that it has stability against earthquakes of Qazvin, which are several richter and very quaky.
– Use of water reservoir during war: In the past centuries, one of the known methods during the siege of cities was to use water reservoirs for war work. In this way, the reservoir became a place for building bullets and fortifications, and several soldiers took shelter in those structures!
Which is the largest historic water reservoir of Iran?
In deciding which historic reservoir of Iran is the largest of this type of structure, there have been discussions. Some consider the Barkeh Kal Gerash reservoir, and others the Sardar Bozorg Qazvin reservoir to be the largest. However, the Barkeh Kal reservoir in Gerash city in Fars province should be recognized as the largest reservoir in Iran. The water accumulated in the Barkeh Kal reservoir is three times that of the Sardar Bozorg Qazvin reservoir.