Estonia's geography: a flat country that cannot drain

Why the water has nowhere to go

Estonia sits on the north-western part of the East European Platform, where that platform meets the Fennoscandian Shield, and the platform is level. The mean elevation is 50 metres above sea level, and only about one tenth of the territory stands above 90 metres. Plains dominate the north and the west; the south and the east are hillier, and the hills there are low.

That absence of gradient is the first term in an equation the rest of the country follows from. The second is the weather. Annual precipitation runs to roughly 600 to 700 millimetres, evaporation is slight, and on ground with no slope to drain along the result is waterlogging. The Estonian Environment Agency describes the same mechanism from the other end: mires form where more water enters the ground than can evaporate or flow away, and their formation is helped by a humid climate, waterproof soil, low relief and a high groundwater table. All four conditions hold here.

So the water stays. Peatland, meaning any part of the ground carrying a thick peat deposit whether or not peat is still forming, covers about 22% of the land area on the Environment Agency's accounting. Mire, the narrower term, means peatland in its natural state with a peat layer thicker than 30 centimetres and deposition uninterrupted, and mires cover about 6%. A separate published figure puts bogs and mires together at about 23%, which is close to the peatland share and a long way from the mire share. The two counts describe different categories of the same wet ground, and both are in print. Peat builds at about a thousand years to the metre in Estonian conditions.

Water not held in peat sits in lakes, and the counts there also depend on the definition. One published figure gives about 1,560 natural lakes; another gives more than 1,400 natural and artificial ones. Internal waters make up 4.6% of the total area. Lake Peipus, at 3,555 square kilometres, is shared with Russia and forms much of the eastern border. Võrtsjärv, at 270 square kilometres, lies in central Estonia.

What the ice left when it melted

The surface is glacial almost everywhere. The south carries moraine hills. The central part of the country is covered with elongated hills with flat tops. Northern Estonia has long narrow swells built from material dropped by rivers running off the melting ice, and extensive sandy tracts mark where the glacier's edge once stood. The result is an undulating surface whose relief is measured in tens of metres.

The one place it is measured in hundreds is the Haanja Upland in the south-east, which holds Suur Munamägi at 318 metres, the highest ground in the country. That summit is itself glacial deposit.

Under the drift the record runs much deeper. The bedrock has two main layers. A crystalline basement of granites, gneisses and other crystalline rocks formed during the Proterozoic; over it lies a sedimentary cover of Palaeozoic rocks, chiefly limestones and sandstones. Above both is a Quaternary surface layer of unconsolidated gravels, sands and clays laid down in the Cenozoic, which is the material the ice moved around. The limestone counts twice: it outcrops as cliffs along the northern coast and on the largest islands, and it is one of the country's worked deposits.

One landform owes nothing to ice. On Saaremaa there is a small and geologically recent cluster of meteorite craters, the largest of them called Kaali, and the impact may have been witnessed by the Iron Age population of the island.

How a flat country carries so much coast

The coastline runs to 3,794 kilometres, wrapped around a territory of roughly 45,000 square kilometres. It is long and shallow and cut everywhere into bays, straits and inlets, and islands account for 9.2% of the country's area.

How many islands there are depends on what is counted. One figure gives 2,355 islands including those in internal waters, of which 2,222 lie in the Baltic Sea. Another gives 1,520 islands along the shore. Saaremaa, at 2,673 square kilometres, and Hiiumaa, at 989, hold most of that island area between them; the rest is islets.

Set the islands beside the lakes and one thing becomes plain. The largest single piece of Estonian territory that is not the mainland is not an island at all.

The northern coast and the largest islands carry limestone cliffs, which is where the Palaeozoic cover reaches the surface and the sea has cut into it. The sea itself is shallow, and the country's ports and ferry routes are arranged around that. Ferry lines to the islands are operated by TS Laevad and Kihnu Veeteed. The port of Muuga, near Tallinn, is ice-free, with a grain elevator, chilled and frozen storage and oil tanker offloading.

Why Estonian rivers stay short

There are more than 7,000 rivers, streams and canals in Estonia, and only ten of them exceed 100 kilometres. One account makes the Võhandu the longest at 162 kilometres, with the Pärnu at 144; Britannica names the Pärnu as the longest at about 145 kilometres. The accounts disagree about which river is longest and agree on the scale: no river in the country runs to 200 kilometres.

Two things keep them short. There is no altitude to fall from, and there is not much country to cross: Estonia spans a little over two degrees of latitude and a little under seven of longitude, so a river reaching the sea from the far side of the country has covered a few hundred kilometres at most.

What feeds them is unusually evenly divided. Groundwater, rainfall and snowmelt each supply approximately one third of the annual runoff. The rivers drain in three directions, to the Gulf of Finland in the north, to the Gulf of Riga in the south-west, and inland into Lake Peipus. The Narva and the Emajõgi are among the most important; the Pedja and the Kasari are also named among the principal rivers.

The snowmelt third is what makes spring the season the water managers watch. Flooding in spring, in certain areas, is the natural hazard the country records.

How the sea decides the winter

The climate is transitional between maritime and continental influences and is classified as humid continental. It is milder than other regions at the same latitude, an effect of the North Atlantic Current, and its day-to-day behaviour is set by cyclonic activity over the northern Atlantic, which brings strong winds, precipitation and abrupt temperature swings, most of all in autumn and winter. Westerly winds carry moist maritime air far inland, which lifts winter temperatures and holds summer ones down.

The Estonian Environment Agency's normals for 1991 to 2020 give a national average of 6.4 °C, with 17.8 °C in July and −3.8 °C in February. The station-by-station spread inside those averages is where the sea shows itself.

Across the whole observation network in the 1991 to 2020 period, the July means fall inside a band of about one degree. The February means fall inside a band of nearly four. A country this small has one summer and two winters, and which winter a place gets is decided by how far it is from open water.

The extremes are wider than the averages suggest. The highest temperature on record is 35.6 °C, set in 1992, with an unofficial reading of 38.0 °C from the same year, and the lowest is −43.5 °C from 1940. Within the 1991 to 2020 normals alone the highest station reading was 35.6 °C at Võru in August and the lowest −36.7 °C at Jõgeva in January.

Precipitation figures vary with the period measured: 662 millimetres a year in one account, with a daily record of 148 millimetres, and 568 millimetres in another, which puts the heaviest fall in late summer. Winds prevail from the west, the south-west and the south, and the average annual wind speed runs between 2.1 and 6.1 metres per second, at its lowest inland and its highest on the west coast.

Latitude does the rest. At Tallinn the longest day of the year lasts 18 hours and 40 minutes and the shortest 6 hours and 2 minutes. Average monthly sunshine ranges from 290 hours in August down to 21 hours in December, and the calculated annual total is 1,830 hours.

What grows on ground that stays wet

Forest covered 51.5% of the land area as of 2023. The 2018 land use accounting gives 52.1%, an older summary 47%, and the area works out at roughly 18,000 square kilometres. Pine accounts for 41% of the growing stock, birch 28% and spruce 23%. Eighty-seven native tree and bush species have been identified along with more than 500 introduced ones, and the territory falls in the Sarmatic mixed forests ecoregion.

The wet ground carries a disproportionate share of the flora. About a quarter of Estonia's 1,500 plant species are found in marshes and swamps. Saaremaa yellow rattle grows on Saaremaa and nowhere else in the world. The wider floristic count runs to an estimated 3,000 algae and cyanobacteria species, 850 lichens and 600 bryophytes.

The animal record is a short list of species and a long list of individuals. Sixty-four mammal species are recorded, along with 11 amphibians and 5 reptiles, and more than 330 bird species have been found. Estimated forest populations include about 700 brown bears, more than 150 wolves, 400 lynx, 14,000 to 16,000 beavers, 10,000 to 11,000 moose, 120,000 to 130,000 deer and 3,400 wild boar. The critically endangered European mink has been reintroduced on Hiiumaa, red deer have been reintroduced after being extirpated, the Siberian flying squirrel holds on in eastern Estonia, and a population of European jackals was confirmed in western Estonia in the early 21st century.

Protected areas cover 19.4% of the land and 23% of the total area once territorial sea is included. Nearly 4,000 protected natural objects are on the register, among them six national parks, 231 nature conservation areas and 154 landscape reserves. Each protected area is governed by a protection rule, a piece of legislation that fixes its boundaries and states which activities are permitted, prohibited or required inside each zone, and by a management plan that sets the conservation work and its order of priority.

What Estonia digs out of the ground

The listed natural resources are oil shale, known locally as kukersite, along with peat, rare earth elements, phosphorite, clay, limestone, sand, dolomite, arable land and sea mud. Several of those are the sedimentary cover and the peat described above, which is to say the country's mineral economy sits in the same two layers as its scenery.

Land use in 2018 was 22.2% agricultural, of which 14% arable, 0.1% permanent crops and 7.2% permanent pasture; 52.1% forest; and 25.7% other. In area terms that is roughly 9,260 square kilometres of arable land, about 2,520 of meadow and about 1,810 of pasture. Irrigated land came to 40 square kilometres. Total renewable water resources were estimated at 12.806 cubic kilometres in 2017, which on this terrain is less a scarcity question than a drainage one.

Oil shale is mined in the north-east and burnt for electricity, and the mining has left large mounds of limestone tailings across the region. In a 1992 government report to the United Nations Conference on the Environment and Development, nearly 75% of the country's air pollution was attributed to two oil shale thermal power stations near Narva.

The other thing in that ground is military. Soviet Army installations covered more than 800 square kilometres of Estonian territory, and jet fuel was dumped into the ground at six air bases. An October 1993 preliminary report by the Ministry of Environment put the worst damage at Tapa, where officials estimated that 6 square kilometres of land were covered by a layer of fuel and 11 square kilometres of underground water were contaminated. The water around the site was undrinkable and was sometimes set alight by local people for winter heat. Cleanup at Tapa, begun with Danish assistance, was estimated to cost as much as 4 million EEK. The ministry assigned a cost of more than 10 billion EEK to the damage done to the country's topsoil and water supply, and allocated 5 million EEK for cleanup work in 1993.

Two towns carry entries of their own. Near Sillamäe, at a former uranium enrichment plant, about 1,200 tons of uranium and about 750 tons of thorium were dumped into a reservoir on the shore of the Gulf of Finland, which was reported to have caused severe health problems among residents of the area. At Paldiski the waste left by Soviet Army nuclear reactors had to be removed. The combined cost of environmental cleanup at the two towns was put at more than 3.5 billion EEK.

Emissions to air have since fallen substantially and the pollution load of wastewater at treatment plants has decreased, both attributed to improved technology and environmental monitoring. Coastal seawater is still polluted in certain locations, and the smaller lakes in agricultural areas are kept under monitoring.

Where the eastern boundary was moved

The land boundary runs to 657 kilometres, 333 of them with Latvia and 324 with Russia. Everything else is water: the Gulf of Finland to the north, the Baltic Sea to the west, and Lake Peipus, which carries much of the line in the east.

From 1920 to 1945 that eastern line lay elsewhere. The Tartu Peace Treaty of 1920 set a border that ran beyond the Narva river in the north-east and beyond the town of Petseri in the south-east. Some 2,300 square kilometres of territory on the far side of the present line was transferred to Soviet Russia at the end of the Second World War. The border treaty with Russia had not been ratified as of May 2021.

At sea the territorial claim is 12 nautical miles, and the exclusive economic zone runs to limits as agreed with Finland, Latvia and Sweden.

Because so much of the perimeter is water and so much of the interior is too, the country's own area is published in more than one form. Three totals are in circulation: 45,339 square kilometres, 45,335 square kilometres alongside the figures of 9.2% islands and 4.6% internal waters, and 45,228 square kilometres split into 42,338 of land and 2,840 of water with a note that the total includes 1,520 islands. They differ by about 111 square kilometres, and each arrives with its own accounting of what counts as an island and what counts as internal water.