A triple point on the move
In central Kazakhstan, the vast, grassy plateau of the Kazakh Uplands holds a hydrological oddity. Here, a single drop of rain can drain to one of three separate drainage basins: the Arctic Ocean, or the huge endorheic (closed) basins of the Aral Sea and Lake Balkhash. This is a triple drainage divide, a point where three watersheds meet. Unlike the dramatic mountain peaks that typically mark such divides, like Triple Divide Peak in Montana, this one is "cryptic". It lies on a peneplain—an ancient mountainous area worn down by millions of years of erosion to a nearly flat surface. The divide is so subtle that it's almost impossible to see on the ground.
What makes this specific watershed so unusual is that its precise location is not fixed. The exact triple point can migrate up to 20 kilometers between wet and dry seasons. This movement is driven by changes in groundwater levels. In this flat landscape, the boundary between watersheds is not defined by surface topography alone but by the underground water table. During wet years, higher groundwater levels can push the divide one way; in dry years, it shifts back. This dynamic nature is caused by the region's low relief and continental climate, which sees sharp variations in annual precipitation of 100-300 mm.