Lithuania's geography: a country assembled out of glacial debris

What the ice left when it went

Lithuania sits at the edge of the North European Plain, and the rock underneath does almost nothing to explain what lies on top of it. Encyclopaedia Britannica states the case plainly: the underlying structures are of little significance for the present terrain, which is a low-lying plain scraped by Ice Age glaciers and then covered by the thick ridge-like deposits those glaciers dropped as they melted. Those deposits are terminal moraines, and they are the only high ground the country has. The ice withdrew between about 25,000 and 22,000 years before present, and everything above the bedrock has been in place since.

Read from the sea inland, the ground arrives in belts. A low coastal strip that geographers call the maritime depression rises gradually eastward. Behind it stands the Žemaičiai Upland, which gives way to the flat expanses of the Middle Lithuanian Lowland, a wide band of glacial lake clays and boulder-studded loams running north to south with waterlogged stretches through it. Further east the Baltic Highlands push into the country and their relief is rumpled: a crowd of small hills with small lakes in the hollows between them, including the Švenčioniai and Ašmena highlands in the extreme east and south-east.

Total area is 65,300 square kilometres, of which 62,680 is land and 2,620 is water. Britannica prints 65,286 square kilometres for the same country, and the fourteen square kilometres between the two figures are a reminder that a national area is a measurement with a method behind it.

The land boundary totals 1,574 km, and the published figures do not all agree. The same geography account that tabulates 576 km for Latvia and 680 km for Belarus gives 453 km and 502 km for those two frontiers a few paragraphs earlier. This catalogue prints the boundary-table figures and records that the shorter pair is also in circulation. The 91 km Polish border is described in that account as short and very busy with international traffic.

The extreme points sit where the belts end. The northern one is near the former village of Lemkinė, on the Nemunėlis in the Biržai district; the eastern one near Vosiūnai in the Ignalina district; the southern one in uninhabited forest at Musteika in the Varėna district, with the southernmost inhabited place at Ašašninkai. The western point is Nida, which stands on the Curonian Spit, so the country's western extremity is a bar of sand. Some geographers place the geographical midpoint of Europe a short distance north of Vilnius, a claim the geography account reports without endorsing.

Why the highest point is hard to fix

The record for this catalogue gives Aukštojas Hill at 294 metres, and the Wikipedia geography article agrees in its table of elevation extremes. The topography section of that same article gives the highest elevation in the country as 297.84 metres. Britannica names a different hill altogether: Mount Juozapinė, in the Ašmena highlands, at 292 metres.

The three figures lie within six metres of one another and the hills they name lie in the same eastern uplands, which is the whole difficulty. A summit here is a moraine rise in farmland. It has no cliff, no treeline and no obvious top, and deciding which rise is the highest waited on surveying accurate to the metre. The morainic hills of the western uplands and the eastern highlands reach no higher than 300 metres anywhere.

The low point needs no survey at all. It is the Baltic Sea at zero metres, and the country's entire vertical range would fit inside one contour interval on a mountain map.

Altitude therefore explains very little here. What explains most of it is drainage: where the meltwater collected, where it left clay and where it left sand. The growing season runs 202 days in the west and 169 days in the east, a gap of a month produced by distance from the sea and by nothing to do with height.

Why Lithuanian rivers meander instead of falling

Lithuania has 758 rivers longer than 10 kilometres, and every one of them drains to the Baltic. They behave the way lowland rivers behave, slowly and in curves, because there is nothing for them to fall down.

The Nemunas is the largest. It runs 917 kilometres in total, rises in Belarus, cuts north through the middle of the country and then turns west for the sea, collecting the Merkys, the Neris, the Nevėžis, the Dubysa, the Jūra, the Minija and the Šešupė on the way. The Neris runs 510 kilometres, the Venta 346 and the Šešupė 298.

Navigation is the exception to all this water. Only 600 kilometres of Lithuanian river is navigable, and the traffic on it is thin: in 2000, 89 inland vessels carried 900,000 tons of cargo, under 1% of the country's total goods traffic. The Nemunas and some of its tributaries are used for internal shipping, and the figures show how little that amounts to beside road and rail.

The rest of the meltwater stayed where it stopped. The country holds 2,833 lakes larger than one hectare and about 1,600 smaller ponds, most of them in the east and south-east where the moraine relief is roughest; Britannica rounds the count to about 3,000. The lake towns sit in that belt, Zarasai and Molėtai among them, along with the Aukštaitija National Park.

Where a hollow never drained at all it became bog. The boggy regions produce large quantities of peat, dried in air and used in both industry and agriculture, and the largest of them is the Čepkeliai Marsh in the south. Total renewable water resources were put at 24.9 cubic kilometres in 2011.

How a moving dune became a shared park

The Curonian Spit is 98 kilometres long and between 0.4 and 4 kilometres wide, and it is young ground. UNESCO dates its formation to about 5,000 years ago, when currents piled sand onto a line of moraine islands and forest later covered the ridge that resulted. The Great Dune Ridge along it separates the Baltic Sea from the shallow Curonian Lagoon, which reaches south into the Kaliningrad Oblast.

Sand of that kind stays where it is only while something holds it. Intensive logging in the 17th and 18th centuries took the cover off, the dunes began moving toward the lagoon, and they buried the oldest settlements as they went. By the turn of the 19th century it had become clear that people could not go on living there without immediate action. Stabilisation work began then and has never stopped. A protective dune ridge was raised along the seashore by the end of the 19th century to stop sand migrating inland, and the Great Dune Ridge itself was reinforced with planted trees and brushwood hedges. Forest and sand now dominate the spit, and the eight small settlements on it cover about 6% of its land.

UNESCO inscribed the spit in 2000 as a cultural landscape under criterion (v): an outstanding example of a sand-dune terrain under constant threat from wind and tide, which survives because of continuous human work against erosion. The property is shared. The Lithuanian half sits inside the Curonian Spit National Park and the Russian half inside Kurshskaya Kosa National Park, with the Lithuanian side administered by the Neringa and Klaipėda municipalities and protected under the Law on Protected Areas of 2001 and the park regulation of 2002.

That spit is most of the coast. The coastline measures 262 kilometres counting the spit's seaward side, and the continental shore accounts for 108 kilometres of it. The one deep opening is at Klaipėda, at the narrow mouth of the lagoon, and it stays free of ice. The territorial sea extends 12 nautical miles and the exclusive economic zone covers 7,031 square kilometres.

Why the climate normal keeps being rewritten

The climate is humid continental in the Köppen classification, Dfb, and transitional in practice: damp Atlantic air alternates with continental Eurasian air, and colder Arctic or warmer southern air arrives less often.

What the average looks like depends on which thirty years are averaged. From 2021 the Lithuanian Hydrometeorological Service has used the 1991 to 2020 standard climate normal, under which the average annual air temperature in Lithuania is 7.4 °C, the warmest month is July at 18.3 °C and the coldest is January at −2.9 °C. The 1981 to 2010 normal it replaced gave 6.9 °C for the year. The half-degree difference is spread unevenly across the calendar, with December, November and February carrying most of it.

The service publishes an example of what that does to ordinary reporting. August 2021 averaged 16.1 °C in Lithuania. Measured against the 1991 to 2020 normal, that August came out 1.4 °C cooler than normal; against the 1981 to 2010 normal it would have been 1.0 °C cooler; against the 1961 to 1990 normal it would have been 0.1 °C cooler, which is to say ordinary. The normal is recalculated every ten years and the 2001 to 2030 figures are due in 2031.

Rainfall is handled the same way. The 1991 to 2020 normal puts average annual precipitation at 695 millimetres, with July the wettest month at 84 millimetres and April the driest at 37. Across the country the spread is much wider than that single figure suggests: about 717 millimetres a year on the coast, about 900 in the Samogitian highlands and about 490 in the east.

Temperature splits along the same line. The coast averages 1.6 °C in January and 17.8 °C in July, while Vilnius averages −3.7 °C in January and 18.1 °C in July. Winter minima on record are −34 °C at the coast and −43 °C in the east. Snow falls every year and can fall from October to April, with sleet in September or May in some years. Severe storms are common near the coast and rare inland to the east. The long record runs well behind the normals: the meteorological service publishes an annual air temperature series for Vilnius from 1778 to 2022, and the Baltic instrumental record of about 250 years shows a warm later eighteenth century, a cool nineteenth, a peak in the 1930s, a dip to the 1960s and warming since.

Drought reached the country in 2002 and set forest and peat bogs alight, and the north-western European heatwave of 2006 covered it as well. The hazards named in the standing account are hurricane-force storms, blizzards, droughts and floods.

Where the drinking water comes from

Almost all of it comes from below. The geography account states that Lithuania and Denmark are the two countries in Europe supplied entirely by fresh groundwater, and Lithuanian consumption of about 0.5 million cubic metres a day amounts to 12 to 14% of the explored resource. Wells reach 30 to 50 metres in most of the country and as deep as 250 metres in the Klaipėda region.

Vilnius draws its centralised supply from deep springs protected from surface pollution, which the same account records as carrying no nitrates or nitrites. Water is cleaned without chemicals, and about 20% of what the country consumes is not filtered at all. Approved mineral water reserves come to about 2.7 million cubic metres a year, of which 4 to 5% is actually produced, and part of that is exported.

Surface water has a separate history and it is a Soviet-era one. Kaunas, a city of about 400,000 people, had no water purification plant until 1999 and its sewage went straight into the Nemunas; tertiary treatment was scheduled to come on line in 2007. The Courland Lagoon, cut off from the sea by the dunes and pine of the spit, is recorded in the same account as heavily contaminated. Forests around Jonava, Mažeikiai and Elektrėnai, the chemical, oil and power-generating centres, show acid-rain damage, and petroleum and chemical contamination of soil and groundwater at former Soviet military bases is listed as a standing environmental issue.

What grows on glacial sand and clay

Lithuanian soils run from sands to heavy clays, and the pattern follows the ice. The north-west is loamy or sandy, sometimes marshy, and heavily podzolized. The central region carries weakly podzolized loamy peats and holds the most fertile and most cultivated ground in the country. The south-east is sandy, somewhat loamy and moderately podzolized. Sandy soils cover a quarter of Lithuania, and most of that quarter is under trees.

Forest covers 32.8% of the country, principally pine, spruce and birch, while ash and oak are scarce. The composition changes with the belts. Pine dominates the maritime region, with wild rye and bushy plants growing on the dunes; spruce prevails in the hilly east; the central region carries oak, with birch to the north and groves of black alder and aspen; pine returns in the south. About a fifth of the country is meadow, and swamp and marsh account for a small share of the total. The forests are productive of mushrooms and berries.

Farming works the middle band. Land use in 2011 was 33.48% arable and 0.47% permanent crops, with 13.4 square kilometres irrigated. The emphasis falls on meat and milk, with flax, sugar beet, potatoes and vegetables, fodder crops and grain, and livestock breeding centred on dairy cattle and pigs. Agriculture since 1991 has been closely tied to land reclamation and swamp-drainage schemes, and the drainage of land for agricultural use is what the standing account blames for the losses in flora and fauna.

What survived is protected on paper in quantity. Lithuania has 1,160 protected cultural and natural areas, among them five national parks, 30 regional parks and six strict reserves. The national parks are Aukštaitija, Žemaitija, Dzūkija, Trakai Historical and Kuršių Nerija on the spit. Birdwatching concentrates on the Nemunas Delta Regional Park, the Žuvintas biosphere reserve and Ventė Cape, all of them wetland.

What the country digs out of the ground

The natural resources listed for Lithuania are peat, arable land and amber. The list is short, and the account carrying it is direct about the gap: energy sources and industrial materials are in short supply.

What the glacial and sedimentary cover does provide is bulk material. Limestone, clay, quartz sand, gypsum sand and dolomite are present in quantity and suit high-quality cement, glass and ceramics. Britannica adds chalk and chalky marl, gravels, phosphorites, some iron ore and mineral waters to the same list. Amber, which is fossil tree resin, is found along the shore of the Baltic Sea.

Oil was discovered in the 1950s, and only a few wells operate, all of them in the west. The Baltic shelf and the western region are estimated to hold commercially viable amounts, perhaps 1,600,000 cubic metres offshore, with the estimate attached that exploitation would meet about 20% of the country's annual need for petroleum products for twenty years. Iron ore has been found in the south, and the south-east could yield high grades of iron ore and granite. Working either would mean strip mining.

The largest untouched resource named is heat. The coast holds thermal energy that the standing account says could warm hundreds of thousands of homes on the Icelandic model, and whether any of it is developed is made conditional there on capital and technology from abroad, the same condition attached to the ore.

Peat is the deposit actually worked in bulk. It comes out of the bogs the ice left, is dried in air, and goes to industry and agriculture, which closes the circle the retreating glaciers opened.