Arkhangelsk Oblast the south-west of the Oblast drains into the Kema River which belongs to the basin of the Caspian Sea. The area in the Onega River basin containing the biggest lakes in the oblast, such as Lake Lacha, Lake Kenozero, Lake Undozero, and Lake Kozhozero. The tundra of the Nenets Autonomous Okrug also contains a number of bigger lakes. The river basin of the Pinega is characteristic of the karst, with a number of caves in the region. The White Sea coast within the Oblast is split into the Onega Bay (where the Onega is the major tributary), the Dvina Bay
Arkhangelsk Oblast most of these became unprofitable and have been destroyed. In the 1970s and 1980s the aviation was active, with all district centers connected to Arkhangelsk with regular flights, Kotlas being the second important hub. Currently, it has almost disappeared. There are two airports in Arkhangelsk, but regular local flights are only carried out to the destinations which do not have rail or road connections, such as Novaya Zemlya, Solovetsky Islands, the Nenets Autonomous Okrug, the Onega Peninsula, and the north of the oblast. The exceptions with functioning airports are Mezen, Leshukonskoye, and Onega. The oil transport system, Baltic Pipeline System,