Lake Karankajärvi empties into pond Hepolampi in south via the river Karajoki. The Rapids Heijostenkosket begins in pond Hepolampi. The river is about 1,8 km long and the rapid fishing ground about 600 metres. A bridge crosses the rapid in the middle of the rapid. Bellow the bridge there separates a canal of a mill from the rapid. Fishing is for bitten in the canal. River Karajoki is restored after log floating. Nowadays there are a plenty of shelters in the pits and near the stones. On the river there are no fireplaces. The river is narrow and therefore it is suitable for UL fishing. On the shore of the river there are a few buildings and areas where fishing is for bitten (the canal of the mill and the northern bed above the bridge). In the river Karajoki there is yearly stocked size limit lake trout but there are also anadromous fish from other rapids (Kouheroistenkoski, Heijostenkosket) and lakes. Grayling is successful naturalized in the rapid in the beginning of 1990’s. Nowadays there is caught big grayling on the river.