The Proletarsk Dam is sufficiently high to raise the water level in Lake Manych-Gudilo upstream from it, so in fact the lake has become part of the Proletarsk Reservoir. The three reservoirs form an almost continuous chain, the original course of the river being almost entirely flooded by them. According to the calculations of the Russian geographer Alexander Bazelyuk, between Manych-Gudilo and the river mouth, merely of the length of the West Manych river remains in its original "river" form: from the Vesyolovsk Dam to the upper reaches of the Ust-Manych Reservoir, and from the Ust-Manych Dam to where the river joins the Don.
Formerly, at least in periods of high water, the Manych River would flow in two directions. The river Kalaus, when reaching the Kuma–Manych Depression at, would split. About 30% of the water would become the West Manych and flow northwest to, or toward, the Don River. The remaining water became the East Manych and flowed roughly southeast and dried up on the steppe before reaching the Caspian Sea. Sometime around 1970 a low dam was built which prevented any water from flowing into the East Manych. The East Manych is now fed by irrigation canals coming from the Kuma and Terek Rivers.
Canals
Historically, both rivers were intermittent. During dry years, and even during the drier parts of normal years, both Manych Rivers would consist merely of a chain of small lakes or ponds with brackish or salty water. The system usually would be fully filled with fresh water only during the spring freshet. Since the mid-20th century both Manych Rivers receive significant amounts of fresh water via a network of irrigation canals. Since 1948–1953, the West Manych has been receiving water from the Kuban River and from the Tsimlyansk Reservoir on the Don. Since the late 1960s, the East Manych has been receiving water from the Terek River and the Kuma River via the Kuma–Manych Canal. According to A. Bazelyuk's calculations, the annual water flow in the West Manych is 8.3 times as high as it was previous to the canal and dam constructions, while that in the East Manych is 4.3 times as high as before. If the plans for the proposed Eurasia Canal, linking the Caspian Sea with the Black Sea, are ever implemented, it will likely follow the Manych valley in its central and western section.
