# How much water will flow into the Caspian Sea if it is connected to the World Ocean?

I wonder how much benefit would a hydroelectrical project built on this inflow bring.

There are projects to fill up the Erie, Salton, Qattara and the Dead Sea. But for the Caspian, there is only a proposal for a Panama-like canal with locks - https://en.wikipedia.org/wiki/Eurasia_Canal.

This picture gives the scale, but not the numbers. https://www.floodmap.net/?ll=43.334232,43.460796&z=5&e=0

I think the Soviets might have done some calculations.

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People living along the banks and flat hinterlands in the flooding areas will not be amused of such an enterprise. I would also say that sacrificing all that potentially fertile land might trigger protests. And as the Caspian water table reaches global sea level, power production will go down.

The mentioned canal would need locks to keep the water from flowing from the Black Sea to the Caspian because the Black Sea only has a ~50m layer of fresh water over a huge basin of anoxic salty waters that contain gases from the decay of organisms. The "interface layer" is unstable, raising it via an outflow of fresh water could eventually cause a release of gasses like hydogen sulfide in a larger scale. Also, the anoxic water below the boundary layer is highly corrosive to machinery.

Power generation with water in such a large scale is cheaper and more sustainable along fresh water currents or in tidal power stations.

Now that was not a real answer, that would have had some math like flooded area * height difference(28m) * fudge factor for topography and a division by the cross section of the inflow to get a feeling for the time it would take to fill the pan, but it has some background on the setting we're talking about.

Hope that helps, if not, let me know :-)

Edit: i just realized that much of my answer is somewhat nonsensical because there is a water divide between the two water bodies from where it goes downhill to both sides. While a closed pipe could be imagined for a constant flow and to drive turbines, it doesn not seem very practical. But that's engineering, not my strength ...

• Thanks for the greetings! You brought up the H2S, which truly may be an issue. I think that the flooding may happen on its own when the global sea level rises. It may be a good idea to conduct it preemptively, under control and with profit. Also, I've noticed that usually, like in this research, people don't even take these power sources into account. Maybe because of their low capacity? Jan 25, 2020 at 19:16
• Wouldn't outflow of the surface layer from Black Sea to Caspian Sea be matched by inflow of Mediterranean Sea water through the Bosphorus? Jan 25, 2020 at 19:36
• Yes. But the inflow from the mediterranean is high saline, dense water. It sheets under the freshwater (with some turbulence in the Bosporus). Freshwater inflow from rivers, precipitation, evaporation would stay the same. Taking from the freshwater table in the Black Sea would lower its freshwater outflow in the Bosporus, while inflow of saline water rises to equalize for the freshwater loss. Thus the boundary layer in the Black Sea would rise. Did this make some sense :-) ?
– user18607
Jan 25, 2020 at 19:59