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Lake Vänern Ever since the first settlements were established here some 10,000 years ago, Vänern has played an important role in people´s lives in this region. Generations have worked and made their livelihoods here. Timber, grain and iron have been transported here. The lake has been a threat to seafarers in stormy weather and to the inhabitants in times of flooding. At other times it has merely symbolised something apparently everlasting when the times have been a-changing all around. All the same, it is not until now that we have really come to see that humans and Vänern are part of a larger symbiotic system. By making choices, by choosing our lifestyle and our way of doing things, we can affect Vänern and the whole of the environment round us. In the 1960s and 1970s Vänern was a badly damaged, almost dying lake. We had badly overestimated its ability to heal itself of the enormous pollution caused by our irresponsible behaviour. This was something we were able to change with time and thought and far-sighted planning, so now we have seen Vänern return to good health and once more be a fantastic natural resource.

Geological history About 900 million years ago a continent collided with the land that we now call Sweden. It was such an almighty collision that mountains thousands of metres high were created. You can see traces of this collision in the landscape round Vänern. The continental plates then separated about 800 million years ago. A large threshold at the lake bed in the middle of the lake-between Värmlandsnäs and Kållandsö shows where the northern land mass was forced under the southern land mass, which was then pushed up to make a high mountain chain. During the following millions of years this mountain chain was eroded to an almost flat surface, but the depression in the bedrock remained and can be seen at the bottom of LakeVänern.

Later, this landscape ended up in the northern hemisphere and went through a series of ice ages; it was during this period that the landscape was shaped into what it is today. The ice that lay several kilometres thick over Vänern slowly melted about 20,000 years ago. The present lake was created about 10,000 years ago. During the following thousands of years large amounts of fresh water flowed into the then salt-water basin from the melting inland ice. The edge of the inland ice remained for a time over this region, moving slowly backwards and forwards. Boulders and stone were deposited, forming the Hinden reef. Vänern was cut off and formed a lake of its own.

Along with the glacier water enormous quantities of clay came into Vänern, covering large areas with a 20-30-metre-thick layer of mud. Seals and whales that had lived in the former sea bay were found thousands of years later in these mud areas. Other fish species such as smelt, salmon trout, salmon and small crustaceans (i.e. Monoporeia affinis, Pallasea quadrispinosa and Gammaracanthus lacustris) adapted to the fresh water and are now recognised as relics of the ice sea in the lake.

But Vänern is still changing today because the whole of the Vänern depression is tipping slowly towards the southwest. The land uplift is about 3½ metres per thousand years in the north near Karlstad and about2.6 metresin the south near Vänersborg.

Water level LakeVänern is in the middle of a great waterway that starts in the Norwegian mountains and runs out into theNorth Sea . At times the water has broken its banks and caused flooding. But in our own times we have taken control of the flow of water by means of locks and dams.

Vänern is born high up in Härjedalen and in neignbouring districts in Norway, even outside where this map starts in a lake called Rogen. The water then continues down to LakeFemunden in the Norwegian mountains. You can see Femunden at the top of the map on the left of the Norwegian border — inside Norway. Then the water flows into the river Klarälven, which supplies Vänern with 35 per cent of its water. There is a close relationship between the snow that melts in the catchment areas and the height of the water in Vänern.

Sometimes high water flows cause flooding. In the autumn of 2000 Arvika in western Värmland at Glafsfjorden suffered one of the most extensive floods that have hit Sweden in modern times. But this flood was not unique compared with the figures measured since official measurements started in Vänern in 1807. Earlier floods hit the population hard when water meadows and fields were put under water, often resulting in severe famine and enormous problems. Regulating the level of water in the lake was an obvious solution.

The first constructions to tame the waters of LakeVänern were floodgates. Sweden´s first floodgate was built at Lilla Edet, Ström in the river Göta älv as early as 1607. At various times in the 17th and 18th centuries work was done on constructing sluices at Stora Edet, Trollhättan. In 1800 the passage past the TrollhättanFalls was opened for boat traffic and the way was open from Vänern to the sea. The idea of mastering Vänern´s vast quantities of water arose at an early date. In 1937 the state water company Vattenfall was authorised to regulate Vänern. This meant broadening Vänern´s outlet so that more water could run out. The lowest limit for damming the water in the year was set at +43.16 metresabove sea level and the highest level in the year at44.85 metres .

At the flooding in January 2001 the height of water in Vänern was45.67 metresabove sea level, which is one of the highest levels since the lake was regulated in 1937.

General biology 150 years ago the landscape round Vänern underwent a major change. It was a necessary change so that the growing population could be fed — but ecologically it was a disaster. Meadows and wetlands were transformed into enormous industrial fields.

The plains surrounding Vänern are of heavy clay that was deposited in the sea that covered the region when the inland ice was melting. Until about the middle of the 19th century there was no technology that allowed these plains to be cultivated, so meadows and wetlands stretched out as far as the eye could see. Even the land that could be cultivated was very heavy, and in his travel book from Västgötaland written in 1742, Per Kalm describes how the farmers at Lanna, south of Lidköping, harnessed no fewer than five draught animals — both horses and oxen – to the plough. So the farmers on the plains round Vänern were in the main cattle farmers.

But this also meant that this varied landscape was very rich in different species. Not least the extensive wetlands were a paradise for insects, frogs and birds. Carl Linnaeus, for example, describes the glories of the flowering meadows in glowing terms. But for the people there this landscape presented problems. In good years it was a rich landscape that allowed plenty of cattle to be bred and sold; but the clayey soil was not able to absorb large downfalls of rain and there were bad years when the crops failed.

The heavy falls of rain around 1830 and the famine the following was the signal for the modernisation and later the industrialisation of the Skaraborg plains. This has resulted in this region being one of Sweden´s most important agricultural districts today. Funds were allocated to dig great dikes throughout Skaraborg to improve the drainage. The farmers could then dig their own open ditches and connect them to the dikes. Water meadows and wetlands were drained everywhere and the level of lakes was lowered to gain arable land for the growing population. In the drainage basin of the LidanRiver more than50,000 acresof lakes and wetlands have disappeared since the mid-19th century. The new landscape was a grain-producing landscape. The real boom for farmers came from exporting oats to England. In industrial England horses played a central role as draught animals, above all in town transport and down the mines, where pit ponies worked. Masses of oats were needed to feed them all, so money started pouring into the region; Skaraborg in particular became more prosperous.

In the mid-nineteenth century, fishing in Vänern moved away from the shore to more open water outside the islands. The nets in those days were made of homespun linen yarn and the fishing boats were rowed or sailed with the help of a sail. Few fishermen used ice and the fish were either transported in water on board or were left to die in the boat. So the distance to and between the fishing areas and trading places was a limiting factor on how much fish was caught and sold. For the area round Kållandsö, Lidköping was a convenient trading place and in the early 1900s Wednesdays and Saturdays were the big market days. That meant that the fishing gear was put out for the fish to be caught on Tuesdays and Fridays so that they could be sold as “fresh fish”. Today the lake hosts 36 permanent species and a total of 44 species including the shorelines and river inlets. The most common fish is smelt and vendace. Arctic char (Salvelinus alpinus) and whitefish (Coregonus spp.) together with pikeperch and perch are common. There are strains of naturally spawning lakemigrating trout (Salmo trutta) in Vänern and three strains of naturally spawning salmon (Salmo salar), the Gullspång, Klarälv and Tidan stocks. A special characteristic of these is that they spend their entire lives in freshwater and do not migrate to the sea. The rivers Gullspångsälven, Klarälven and TidanRiver are the only sites within eu where this type of land-locked salmon still spawns.

Together they make up a bit more than half of the country´s licensed lake-fishermen. The economically most important fish is vendace which is fished for its roe. Commercial fishermen have catches an average of approximately 890 tons of fish in Vänern.

Osprey (Pandion haliaetus) is a typical species of the lakes. Birds of prey decreased enormously during the 20th century due to both hunting and environmental toxins. Toxins, such as mercury, pcb and ddt have been banned and the birds have been placed under protection. The increase in birds of prey can be taken as a sign of a cleaner environment and the marsh harrier (Circus aeruginosus) is nowadays common in the reed beds. The sea eagle (Haliaeetus albicilla) has returned to breed in both Vänern.

The continental cormorant (Phalacrocorax carbo sinensis) has increased in the lake, posing somewhat of a problem for the commercial fishers since the birds sometimes damage the catch. On the other hand a number of endangered bird species seek protection, from e.g. nest-plundering minks, in the cormorant colony.LakeVänernhas northernEurope ´s largest freshwater archipelago with 22 000 islands, islets and skerries. The lake has plenty of nesting birds and is also an important resting site for migrating birds in the spring and autumn. Vänern is distinguished by the many skerries with colonies of breeding waterfowl of which several species are normally considered seabirds. The most common birds in the lake are the common gull (Larus canus), the tern and herring gull (Larus argentatus). Several endangered species breed in Vänern, such as the black-throated diver (Gavia arctica), turnstone (Arenaria interpres), Caspian tern (Sterna caspia) and bittern (Botaurus stellaris).

Environmental pollution The first constructions to tame the waters of LakeVänern were floodgates. Sweden´s first floodgate was built at Lilla Edet, Ström in the river Göta älv as early as 1607. At various times in the 17th and 18th centuries work was done on constructing sluices at Stora Edet, Trollhättan. In 1800 the passage past the TrollhättanFalls was opened for boat traffic and the way was open from Vänern to the sea. The idea of mastering Vänern´s vast quantities of water arose at an early date. In 1937 the state water company Vattenfall was authorised to regulate Vänern. This meant broadening Vänern´s outlet so that more water could run out. The lowest limit for damming the water in the year was set at +43.16 metresabove sea level and the highest level in the year at44.85 metres . The power station dams and water regulations led to the extinction of many strains of fish. The water level in Vänern was regulated in 1935. The lake has also been exposed to sewage and wastewater from industries and urban areas since the beginning of the 20th century. In the proximity of industries and towns, there was often a foul-smelling mess in the water.

The paper and pulp mills´ discharge of fibres and mercury into LakeVänern was extensive. At its worst, in the 60s and 70s, pike fished from part of the lake was not fit for human consumption due to the high concentrations of mercury. In 1969, an environment protection law was passed that came to have great influence on the lakes´ recovery. Authorities, as well as industry, were forced into a new environmental consciousness. Mercury was also banned, government subsidies were granted for environmental protection measures, and new technologies were developed. During the 70s sewage treatment was vastly improved. In industry, wastewater purification was developed, as were production methods.

The sum of all of these measures led to the lakes´ condition eventually improving. The large and visible discharges of fibres and wastewater lessened. Levels of phosphorus decreased and water transparency increased. Concentrations of organic material decreased drastically in LakeVänern and discharges containing mercury have stopped. Despite decreasing levels of toxins in fish, e.g. mercury, ddt and pcb, concentrations of toxins are still heightened in lakeVänern and fatty fish are subject to limiting recommendations for human consumption. The lakes Vänern are extremely nutrient-poor and therewith also more sensitive to environmental toxins than the nutrient-rich lakes. Reeds have spread and become denser in many bays and archipelagos. The coverage of bushes and trees on islands and shores has also greatly increased since the 1970s. The cause of this overgrowth is not clear and may depend on e.g. water regulation, climate changes, excess nitrogen and decreased grazing.

However, LakeVänern water can, far from land, be drunk as it is without any purification.

A local Hero During the 1940s and 1950s a young man in Karlstad, Hugo Hassel, had started to noticed disturbing changes in Kattfjorden near Skoghalls Paper Mill and he was convinced that the “villain” was Uddeholm´s large sulphite factory. For twenty years this factory had been discharging all its polluted waste water directly into the lake. All the chemicals and fibres from the factory had turned the water in VänernBay into a horrible, stinking thick soup!

Asked by nobody and without any formal qualifications Hugo Hassel began to carry out his own investigations to find out what was wrong with LakeVänern. His efforts saved Vänern from being poisoned, but it was a case of David battling against Goliath.

But the worst thing was that Skogshalls Paper Mill was not alone in polluting Vänern. There were many other industries round the lake, and many districts lacked sewage works. Hugo Hassel took many water samples, collected fish with suspicious-looking signs of disease and paid out of his own pocket to have all the samples analysed. He carried out diving expeditions to investigate the lake bed near the sulphite factory. He flew over the lake, observing and photographing anything of interest — and the more he saw, the more alarmed he became.

For many years he obstinately persevered with his battle against the pollution, arousing and keeping alive popular opinion against what he saw as the murder of the lake by poisoning. At the same time, all over Sweden people were beginning to develop an understanding and a more modern attitude towards the environment — which in the 1960s resulted in the passing of our first environmental protection laws.

Skogshalls Paper Mill tried to discredit Hassel, but he never gave up his battle to save Vänern from being poisoned. But now he was not alone. More and more environmentally conscious people joined his campaign and even the authorities took part in the battle to save the lake. In the end, Skogshalls Paper Mill was investigated by the National Franchise Board for Environmental Protection and was forced, step by step, to introduce better techniques for cleaning its waste water. Now LakeVänern was in focus. County Councils and the National Environment Protection Board carried out an examination of the state of health of the lake that had been eagerly awaited by many people for a very long time. The municipalities also got going and started building sewage works round the lake.