Black Sea–Caspian Steppe The Manych Depression is not much more than 65 feet above sea level and the area around Astrakhan and part of Kalmykia is below sea level. Rivers: Through the center runs the northwest-tending Kuma-Manych Depression. This was once a strait connecting the Black and Caspian Seas and is now marked by the Manych River which is basically a chain of lakes. It will probably be the route of the Eurasia Canal if that great engineering work is ever built. In the south the rivers that flow north from the Caucasus are caught by the west-flowing Kuban River and the east-flowing
Black Sea deluge hypothesis Sea basin. This hypothesis concerns the occurrence of the last inflow and the primary point of controversy is whether the event was gradual or catastrophic. In 1997, William Ryan, Walter Pitman and their colleagues published their hypothesis that a massive flooding of the Black Sea occurred about 5600 BC through the Bosphorus. Before that date, glacial meltwater had turned the Black and Caspian Seas into vast freshwater lakes draining into the Aegean Sea. As glaciers retreated, some of the rivers emptying into the Black Sea declined in volume and changed course to drain into the North Sea. The levels of