There was a short article about dams in Egypt and India. But these turned out to be fill dams.
We came across information on more serious hydraulic structures - ancient stone dams in Spain.
In Spain, 18 km from Alicante, there is a dam called Tibi (also called the Alacantí Dam):
Official information:
It is the oldest non-Roman hydraulic structure in Spain.
Link to the map.
Promotional video:
The dam was built very competently. Not only is it an arched-gravitational type (according to modern classification) - it is also located on the river in the place where the river crosses a high rocky ridge. The dam with its edges abuts against the rocky shores - and the pressure of the water expands it.
The water runoff in case of overflow of the reservoir is well thought out. In the photo, it is visible on the left.
The water from the reservoir flows down to the stone ledges and extinguishes its energy. Very competently - nothing washes away and the efforts of builders have not been spent on this system. Perhaps this system was made recently, because no strong traces of water erosion on the rock have been observed for 400 years. And earlier, the water was drained from this:
There are some culverts at the base of the dam. Probably, water was drained through them when overflowing. It worked like this: the water intake was located at the design level on the slope of the reservoir. Water passed through it and through the body of the dam and came out at the foot from the other side.
Can you imagine the level of calculations (or building experience?)! The level is not lower than design institutes in the USSR. But only we built reinforced concrete dams. And here the stone blocks and the reliability of their construction should be even higher!
Most likely now this drain is closed, because it is very risky to exploit it after centuries.
Imagine how many blocks had to be cut, moved and stacked ?! And all this in 14 years. Even in the days of the USSR, with the availability of technology, concrete dams were not poured over such a period. Surprisingly, water filtration is not visible through the dam body.
Video with views of the reservoir and the dam itself:
This is not the only ancient dam in Spain. Next object:
Dam Pantano de Elche:
Quote:
Link to the map.
Also arched-gravity type. So, there were calculations of its thickness, radius, height. Such objects are not built by eye. This once again emphasizes that in those days in Spain there were engineers who could calculate not only the design of a building, but also such a grandiose structure as a dam. Calculation with a margin, because the dam is still standing.
It's amazing that water flows down from the dam. Although the culverts are also visible on the right in the photo. They do not work, like the Tibi dam. Perhaps the decision was made to close them due to deterioration and the risk of dam failure. But nothing better was invented than to allow the water to overflow.
The result is a waterfall. But it causes no less damage to the dam due to water erosion.
Yes, water just overflows over the edge of the dam. Sooner or later, this can lead to block damage and avalanche destruction in floods. Local authorities should think about it. There are many examples of dam destruction in history.
Video of the trip to this dam:
There is an even older dam in Spain: the Almansa Dam:
Height 25 m. It was erected in 1384, reconstructed several times. There is no information about it in runet.
Spain is not the only country with such ancient dams. They also exist where complex engineering structures appeared only in the 19th and 20th centuries.