| Kochechum | |
| Map: | Nizhnyaya_Tunguska.png |
| Map Size: | 270px |
| Subdivision Type1: | Country |
| Subdivision Name1: | Russia |
| Subdivision Type2: | Federal subject |
| Subdivision Name2: | Krasnoyarsk Krai |
| Subdivision Type5: | City |
| Subdivision Name5: | Tura |
| Length: | 733km (455miles) |
| Discharge1 Location: | mouth |
| Discharge1 Avg: | 600m3/s |
| Source1 Location: | Central Siberian Plateau |
| Mouth: | Nizhnyaya Tunguska |
| Mouth Elevation: | 125m (410feet) |
| Basin Size: | 96400km2 |
The Kochechum (Russian: Кочечум) is a river in Siberia, Russia. It flows through the Syverma Plateau in Krasnoyarsk Krai. It is a right and most significant tributary of the Nizhnyaya Tunguska.
The river is 733km (455miles) long, and its watershed covers 96400km2. The average discharge at the mouth is 600m3/s.[1] The part of its basin near the source lies on the southern slopes of Putorana Plateau. It flows to the south direction through Syverma Plateau and joins Nizhnyaya Tunguska near the town Tura. The primary tributaries of the Kochechum are Embenchime, Tembenchi and Turu.
The confluence of Kochechum and Nizhnyaya Tunguska corresponds to the farthest point of fairway section upstream off the Yenisey.
The basin of the river entirely belongs to the zone of continental subarctic climate. Winter period starts in October and ends in May, during calendar winter temperatures can plummet below -60C. Due to average temperatures below freezing in this area, its watershed belongs to the region of continuous permafrost with a frozen layer that varies in depth between 50mand200mm (160feetand700feetm). The permafrost effectively blocks any underground supply; all water flowing through the river comes from snow and rain. The river stays ice-bound from October to May or June every year.
As watershed area does not contain any significant lakes. The flow of the Kochechum strongly depends on the season, approaching zero in early spring and reaching its maximum in June.[2] The latter month corresponds to a seasonal inundation, which usually produces 75 percent of the overall annual yield of water.