The Lena Delta is the great fan of channels, islands and lakes where the Lena River, the 4,294 km river that drains much of eastern Siberia, enters the Laptev Sea of the Arctic Ocean in the Sakha Republic (Yakutia), Russia. Wikipedia’s articles on the river and its reserve give the delta an area of about 30,000 km², reaching some 100 km out into the sea and about 400 km across; Russian sources put it larger, at about 45,000 km². It is a treeless, permafrost tundra wetland, frozen for about seven months a year and covered with more than 30,000 lakes, and much of it is protected in the Ust-Lensky Zapovednik, a strict nature reserve of 14,330 km² created on 18 December 1985. The best way to understand it is to travel through it the way the water does, from the last narrows of the river to the open sea.
Kyusyur and the last narrows between the Kharaulakh and Chekanovsky ranges
By the time the Lena reaches its lower course it has collected the Vitim, the Olyokma, the Aldan and the Vilyuy, and carries about 489 km³ of water a year. Below Yakutsk it flows north across the Central Yakutian Lowland, then bends and runs almost due north between two lines of hills: the Kharaulakh Range to the east, part of the Verkhoyansk system, and the Chekanovsky Ridge to the west. Here the river runs in a single valley between the hills, the last time it will flow as one channel.
The last village before the delta is Kyusyur, on the right bank of the Lena a few kilometres south of the mouth of the Eyekit and about 120 km from the district centre of Tiksi. It had 1,345 people at the 2010 census and is the only inhabited place in its rural district. Its climate is extremely continental and subarctic, with long, very cold winters and short, mild summers. River traffic depends on that short season: in the estuary region the navigation period, when there is little or no ice, lasts only about 70 days a year, compared with about 125 days upstream.
Stolb Island, where the delta begins about 150 km from the sea
The delta proper starts roughly 150 km from the Laptev Sea, and its gateway is marked by a single rock. Stolb Island, whose name means pillar, rises out of the river at the head of the delta. Russian Wikipedia describes it as a remnant left behind when the water cut through one of the spurs of the Kharaulakh Range, so it is a piece of mountain standing in the middle of the river, surrounded by low, flat islands of river sediment.
Below Stolb the Lena divides again and again. Wikipedia’s account names seven main branches; Russian sources note that only three run without a break to the sea: the Olenyok Channel in the west, the Trofimov Channel in the middle and the Bykovsky Channel in the east. Between them lie countless low islands, islets, side channels and lakes, flooded in the spring high water and constantly changing shape. The first survey of this maze was made by the Lena–Yenisei detachment of the Great Northern Expedition under Vasily Pronchishchev, which described and mapped the delta in August 1735, eighty years after Russian travellers first reached it in 1655.
The Bykovsky Channel: 106 km east to Tiksi Bay
Turning east at the head of the delta, the first route is the one ships use. The Bykovsky Channel, the easternmost of the three main outlets, is about 106 km long and the most important for navigation, because it leads to Tiksi Bay. Wikipedia’s Lena River article calls it the most important of the delta’s branches. On the shore of that bay stands the port of Tiksi, described in Russian sources as the sea gate of Yakutia.
Tiksi lies on the Buor-Khaya Gulf of the Laptev Sea, southeast of the delta, and is the administrative centre of Bulunsky District. Modern Tiksi was founded in 1933 and became an urban-type settlement in 1939; at the 2010 census it had 5,063 people, a sharp fall from its Soviet peak, with many apartment blocks abandoned. The bay has older history too. The Russian polar ship Zarya, used by Baron Eduard Toll in his search for Sannikov Land, a reported Arctic island that was never found, ended her days here: badly damaged by ice, she was moored near Brusneva Island in Tiksi Bay, stripped and left to fill with water on 6 August 1903. Toll and three companions had vanished in November 1902 while crossing loose ice south from Bennett Island, and the remaining crew returned to Saint Petersburg.
East of the delta the hills return. The Sokol section of the Ust-Lensky reserve, about 1,330 km², protects the northern spurs of the range on the eastern side of the delta, where tundra gives way above about 500 m to a bare mountain belt.
Down the Trofimov Channel, carrier of 70% of the Lena’s water
The middle route is the river’s main artery. The Trofimov Channel takes about 70% of the Lena’s flow, and it crosses the deltaic section of the Ust-Lensky Zapovednik. That section, between the Arynskaya and Machaa-Yuyose channels, covers about 13,000 km², 91% of the reserve. Russian sources describe it as half water: lakes make up about a fifth of it and bays and channels more than a quarter.
The land between the channels is a mosaic of grass, shrub, lichen and moss tundra and tundra bog, with narrow fringes of dwarf willow, sedges and herbs along the channel banks. Snow lies for 250 to 270 days a year, the frost-free season lasts only about 40 to 45 days, and in summer the ground thaws to a depth of only 10 to 120 cm before refreezing. Beneath that thin active layer lies permafrost, which underlies the whole Lena basin and is continuous over more than 75% of it, and the frozen ground preserves Ice Age remains: mammoth tusks have been dug out of the delta.
The Olenyok Channel and Arga Muora Sise in the west
The westernmost route, the Olenyok Channel, leads to a very different part of the delta. The western part of the delta is dominated by Arga Muora Sise, also called Arga Island. At about 6,500 km² it is the largest island in the delta and ranks as the 99th-largest island in the world. It is a low plain of sandy sediments pocked with thermokarst lakes, formed where melting ground ice lets the surface collapse; the largest is Lake Nikolay. Wind and erosion keep reshaping it, and whether the island was first formed by glacial or periglacial processes remains disputed.
On satellite images the difference is obvious: Arga Muora Sise appears as an orange-brown block scattered with round lakes, while the active delta to its east is a dense green web of channels. Off the western shore runs Turukannakh-Kumaga, a long, narrow island. Wikipedia’s list of the delta’s other main islands, from west to east, begins with Chychas Aryta, Petrushka and Sagastyr.
Inside the Ust-Lensky Zapovednik: reindeer, walrus and 109 bird species
Whichever channel you follow, much of the journey is through the reserve. Its surveys list 402 species of vascular plants, 32 fish, 109 birds and 33 mammals. The wild reindeer of the Bulun population, up to 70,000 animals, use the delta for calving and summer grazing, and Arctic foxes breed there in large numbers. Muskoxen, which died out in Siberia about 2,600 years ago, were brought from the Taimyr Reserve in 1996 and have settled in well. On the coast, walruses of the Laptev subspecies, wiped out from these waters in the 1940s, have begun returning to their old haul-outs, possibly because shipping has declined.
In summer the delta’s lakes and channels fill with breeding swans, geese, ducks, loons, waders and gulls, among them the Bewick’s swan, listed in Russia’s Red Data Book, and the Ross’s gull. The reserve’s waters hold nelma, muksun, broad whitefish and sturgeon, and the protected delta contains traditional spawning grounds of salmonid and whitefish species whose numbers have fallen sharply elsewhere on the Lena. One island holds a surprise: on Tit-Ary, at around 72° N, Dahurian larch trees grow up to 6 m tall, a stand described as the northernmost forest in the world.
The outer islands and the Laptev Sea edge, from Amerika-Kuba-Aryta to the Jeannette survivors
At the seaward edge the delta breaks into the low outer islands. On its northern margin lies Ostrov Amerika-Kuba-Aryta, a name that may come from the Soviet-era friendship with Cuba or, if it is older, from kuba, the Yakut word for swan. Offshore, the Bogatyrev shoal was named in 1920 by Fyodor Matisen, who mapped the delta, after the Yakut Afanasy Bogatyrev.
This coast is where the Jeannette expedition ended. In September 1881 two of the three boat parties from the American ship Jeannette, lost in the Arctic pack ice, reached the Lena Delta. The group led by engineer George W. Melville was rescued by local Tungus hunters; of Captain George W. De Long’s party, only two men survived, and the rest died of starvation among the channels. Four years later, Eduard Toll and Alexander von Bunge explored the delta and the New Siberian Islands for the Imperial Academy of Sciences.
Beyond the outer islands the fresh water of the Lena spreads into the Laptev Sea, which is frozen for most of the year. For the river’s full course from the Baikal Mountains, read our Lena River guide; for the sea it feeds, see the Laptev Sea guide; and for the frozen ground beneath every island here, our explainer on what permafrost is.