Umbolka headwater begins in the west slope of Koashva mountain at height of more than 600 meters above the sea level and flows in southern direction. To the east of road junction to settlements Koashva and Oktyabr’sky, the riverbed changes its direction to north-east and goes along forest and marshy ground alternately. It has many rapids.
Riverbed goes through Kitchepakhk and Kitchejavr lakes. Main inflow Vuonnemjok (through Kitchepakhk lake). In the upper stream it is called Rasvumjok. It flows into Umbozero lake at approximate height of 149 meters above the sea level.
Vuonnemjok river has two riverheads, the first main one begins at Yuksporlak pass and goes along the Khibiny massif from west to east. It flows from height of 500 meters along the forests and marshy places with velocity of 0.3 meters per second. Its length is 30 kilometers; water basin area is 110 square kilometers. Before river comes to Koashva settlement it is filled by waters of three inflows coming from river valley in the north.
Another northern Vuonnemjok riverhead replenishes its waters in the east of Koashva settlement. Then riverhead passes forest marshy areas in the south-eastern direction and flows into unnamed lake and through lake Kitchejavr to Umbolka river, of length 42 kilometer which in turn is inflow of Umbozero lake.
Its upper stream has many rapids and it is called Rasvumjok. Vuonnemjok river is famous as first deposits of «arkite» mineral were discovered near its shores.