In arid regions of Central Asia, cyclicity in the humidification behavior of a region shows long-term trends of changes in the levels of closed lakes. Thus, the last 10 years saw a decrease in the water level by several meters on one of the region’s largest lakes – Hulun Nur (PRC). For water level stabilization on the PRC’s territory, a package of measures is undertaken for a partial Hailar river flow diversion (in the upper reaches of the Argun’ river) to Lake Hulun Nur. It is obvious that the lake’s level regime will experience substantial changes. This paper discusses a variety of consequences of the river flow diversion and different water economy management modes, and forecasts the lake’s possible level regime, the Argun’ river discharge and the ecological consequences of measures of this kind for the Russian part of the drainage basin.Keywords: river flow diversion, water economy model, hydrological regime, ecological consequences.