Rioni

a river in the Georgian SSR. It is 327 km long and drains an area of 13,400 sq km. The river originates from glaciers on the southern slope of the Glavnyi, or Vodorazdel’nyi, Range in the Greater Caucasus.

The Rioni first flows through a deep narrow gorge and then in a wide valley between the Lechkhumi and Racha ranges, from which it again flows through a narrow gorge. Below the city of Kutaisi the river flows across the Colchis Lowland, where it branches. Embankments on either side of the channel elevate the Rioni above the surrounding area; the river here is meandering. The Rioni forms a delta where it empties into the Black Sea. Most of the flow (as much as 90 percent) is discharged into the sea by way of a canal built in 1939 to protect the city of Poti during heavy flooding.

The Rioni is fed in various ways, predominantly by rain; its upper course is fed by glaciers. High water is from March through October, and there is flooding throughout the year. At its mouth, the river has a mean flow rate of 405 cu m per sec. The water is noted for its high turbidity; in spring the turbidity reaches 2,650 g per cu m. The Gumati and Rioni hydroelectric power plants are located on the river. In its middle course, water from the Rioni is used for irrigation. The Ossetian Military Road passes through the river’s valley. From its mouth, the Rioni is navigable for 95 km. The cities of Oni, Kutaisi, and Poti are located on the river.