Marianne Spolen gjorde denna batikbild till Hornborgasjöns ära      Drainage of Lake Hornborga-2017    

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This paper was written in the year 1962 to a conference Conservation and management of temperate marshes, bogs and wetland arranged by the International Union for Conservation Of Nature And Natural Resources in Les Saintes Marie de la Mer in France.

Summary: The paper deals with the attempts to drain the lake Hornborga, until sixty (now almost 100)  years ago Swedens´ richest residence for waterfowl with an area of 10 square miles.

The last draining was made in the years 1902-1962 and rendered heavy financial losses. The reasons are: miscalculations of the technical costs and of agricultural value, total loss of the earlier rich fishing, loss of waterpower, fifty years lawsuit, an improper water legislation and the necessity to use the entire lake area as a reservoir during spring floods.

It is presumed that economical reasons will make it necessary to replace the present system of extreme draining by a less costly regulation of the water by a regulation dam at the outflow of the lake. With this the following advantage would be gained

  • operating cost will be low without reducing the yield of land effected
  • permanent but controlled water level.
  • regaining of waterpower.
  • partial restoring of valuable fishing and of a wildfowl population and an all over saving of remaining of the former vegetation and rich fauna, of inestimable value for future research.

P O Swanberg

The draining of Lake Hornborga in Sweden. A financial failure and the reasons for it.

In central Sweden, between Skara and  Skövde is Lake Hornborga. For the least 6000 years it has been a shallow, silurian plain lake, in summer not more than 2 m deep. For thousands of years it has had a luxurious vegetation, and a rich fauna. In 1900 its area was approximately 10 square miles. At that time it was Swedens´ richest bird lake.

The shallowness of water enticed people to attempt to drain it, "to transform the bottom into fertile fields and meadows", as long ago as the early years of the 19ht century. Attempts were made in 1803, 1850 and during the 1870´s. All of them were grave financial losses. Nevertheless, in 1903 an agricultural engineer thought he could find a technical solution that would yield a farming profit of 600 000 Skr on a capital outlay of 250 000 Skr, a profit more than twice as large as the expenditure.

After much disappointment another lowering of the water of the lake was made during the years 1932-35.

Today the two projects are united in one, which has not yet been completed. The ten square mile of the lake is now an equally large marsh. The money sunk in the project since 1902 amounts to 4 mil Skr. The necessary annual maintenance costs of the project are equivalent to capital outlay of 500 000 Skr. The gross profit has, for a long time, been far lower than was expected. No attempts have been made to assess the value of the lake in its present form, as a march instead of a lake since 1902.

Even if the 4 million Skr already invested are ignored, it is unlikely that the profit of agriculture can compensate for the costs of continued maintenance.

Reasons why this disastrous drainage project could be permitted.

  • There was, and still is, in Sweden a law which is so formulated that it is obvious that it has been enacted to facilitate the lowering of the levels of lakes, and other drainage projects. The tendentious formulation of the law easily gives rice to the prejudiced view among those with the right of decision that drainage projects are in principle for the benefit of the public, and should therefore be encouraged
  • When  it is to be decides whether a drainage project is to allowed, the profits of the project must be weighed against its costs. In case of Lake Hornborga the profit was calculated in the usual way as the capitalised values of the expected increase in annual yield of agricultural products from the area under consideration.
  • In the assessment of costs, on the other hand, only the calculated costs of the first digging of the necessary drainage channels were taken into account, ignoring
    • a. the costs of the very great annual maintenance of the draining of the lakes,
    • b. the increased costs of cultivation of the area
    • c. the loss of the very extensive fishing, which alone was approximately equivalent to profit calculated for the drainage product,
    • d. loss of water power for the hydro-electric generating stations, which used, and still use, the 50 m head of water in the outflow river of the lake.
  • The agricultural engineers have miscalculated the changes in the value of the land in question, the time required for, and other costs of the necessary work.
  • In Sweden there is still a law which makes it possible for landowners who can expect to get more than half of the anticipated profit of the drainage to compel other landowners whose land is affected by the drainage project to contribute towards the work and its maintenance.
  • The lowering of Lake Hornborga was requested by 17 landowners. Since these owned the best parts of the expected gain in land, more than 200 other holdings, the owners of which did not want Lake Hornborga to be drained, were compelled by law to contribute towards the drainage and its maintenance.
  • The knowledge that many other people must help to pay has probably increased the unrealistic optimism of the few farmers who wanted the project to be carried through.
  • The possibility of obtaining financial assistance from the State is easily conducive of unwarranted and exaggerated optimism. The state granted 900 000 Skr towards the lowering of level of Lake Hornborga, as well as loan of nearly 500 000 Skr, partly free of interest. It is easy to take great risks to gain such large sums of money.

Reasons why Lake Hornborga project has led to such great financial losses.

At the request of the Government, the State agricultural engineer made in 1927, i.e. 23 years after the start of project, an estimation of the gross profit of the venture. The sum was 275 000 Skr.

At the end of 1932 the known costs amounted to approximately 2 730 000 Skr. Thus the costs were about 10 times as great as the profit.

The result was a catastrophe for all the small farmers. In a petition to Government and Parliament the County Council stated in 1933 that "the whole district is threatened with economic destitution".

This resulted in a grant of 900 000 Skr by the State toward the drainage project, and more drainage channels were dug during1932-35. By 1958 the project had cost a further 1 250 000 Skr, and the State agricultural engineer had reported in 1949 that the work done since 1932 had had "Insignificant drainage effect".

As mentioned above, no attempt at an objective assessment of the actual gross profit of the drainage project has been made. This profit ha , however, been far less than the modest profit counted on beforehand.

The reasons for this are as follows:

  1. The inflow of water into the lake may, during spring floods, be more than 3 000 000 cu m a day. The outflow may not exceed 1 750 000 cu m a day. Thus the lake will still have to be used as a reservoir. In 1902 it was calculated that 3200 acres of the bottom of the lake could be drained. In 1932 it was claimed that still another 3200 acres of the original more than 6400 acre bottom could be drained. Nothing of this could be accomplished, however, for the lake must still be retained a reservoir.
  2. In 1902 it was claimed that 4200 acres of land above the then low-water level would be improved by lowering the subsoil water level. This land is mainly peat soil. After the ground had dried the soil became consolidated and the degree of drainage has been less than calculated.
  3. The peat soil has been exposed to high degree of so called sulphur poisoning, which has increased the acidity of the soil after a period of drainage. This and other qualitative features of the peat soil have made it impossible to cultivate some regions, while the value of others as arable land has been very small.
  4. The meadow areas, which were to be gained around the lake have a vegetation consisting of Carex and Salix. Such areas can be used during short period only. Nowadays labour is to expensive to exploit vegetation of such low fodder value.
  5. To maintain the level of the water, 11.8 miles of drainage channels have been dug through the bottom of the lake , which consists of soft mud. This means that the channels soon silt up again. Every year the channels must be re-dug, which is very expensive.
  6. The State agricultural engineer held the view that fertilisers and raw material for the manufacture of cement could be taken from calcareous layers at the bottom the lake. The agricultural engineer claimed in 1907 that he had calculated that on one estate alone 100 000 barrels of cement could be produced annually. None of this has been realised.
  7. There were formerly 17 professional fishermen living by the lake and hundred or so part time fishermen. The fishing has been destroyed by the draining of the lake and the consequent drying up in summer and the growth of vegetation. It has been calculated in 1954 that the value of spoilt fishing amount to 800 000 Skr.
  8. For a very long time the lake has been a natural water reservoir for about 20 hydro-electric power stations, which exploit the total 50 m head of the outlet of the lake. The lowering of the water level of the lake has reduced this reserve of water considerably, which has led to legal proceedings during the past 50 years. In 1932 a Royal Commission reported that water power to the value of more than 1 000 000 Skr had been lost during the first 22 years of this period alone. The costs of the proceedings have been very high, too.

Some direct assessable material affects of the lowering of the water level have been presented above. To these must be added the very great loss of the original Lake Hornborga as an object of scientific research and for general education, as well as the heavy loss of waterfowl as an object of shooting. One the duck shooting there was one of the most important in Sweden, but no significant figures are known. The value of the original lake to the scenery can hardly be overestimated

What can be done to restore Lake Hornborga?

To attain legal conditions at the lake, proceedings have been going on since 1954 between the Royal Treasury Board, appellant, and the drainage company, defendant.

Pending the result of this process, 3200 acres of the former have been dammed off in such a way that the dammed off area is filled with high water, and the water does not run off at low water. This has been done by marking out for damming an area bounded on two sides by former shores of the lake , while the other two sides are bounded by channels. During repeated digging of these channels the silt has been thrown up to form a low bank, 10 km long, along the side of the channel towards the area to be kept under water. The bank has become reinforced by the natural root systems of vegetation, but it is exposed to grave erosion. It is unsuitable as a permanent dam, but valuable as an emergency barrage during the decades that will elapse before the legal decision determining the fate of the lake has been made.

This temporary dam has stopped the earlier, annual, almost total summer drying up of the water, and in this half of the lake there is now a low, but regular summer water level. The water is then 0.9 m deep in the deepest parts.

The growth of vegetation, which earlier covered more than 90 % of this area, has been stopped. The Phragmites vegetation has been reduced in restricted areas, certain Carex areas have been replaced by more or less open stretches of water, where another form of vegetation is developing, and large patches of Salices are shrinking and dying away. The lower plant and animal life, so essential for fish and bird life, has revived in considerable way. Some fishing is going on today and birds has greatly increased. The lake is wow once again one of Sweden's richest bird lakes.

It is clear however, that work continued in keeping with the present technical system must en uneconomical and technically indefensible.

We must resume, therefore, that the present system of continual cleaning of channels will be placed by a less costly regulation of the water by a regulating dam at the outflow of the lake. With this following advantages would be gained:

  1. Operating costs will be low.
  2. Much water power can be gained.
  3. Much fishing can be restored, and wildfowl population of great economic value may be regained.

The whole of the former lake area can, to a certain controlled level, be kept permanently filled with water, at the same time as the earlier floods, so disastrous to farmers, can be prevented.

This is illustrated by proclamation of the water court, which said that a water level, which in summer is lower than the former water level by only 0.5m, and in winter by only 0.2 m would in no way reduce the yield of the land affected by the lowering of the water level. Since the land in question, according to modern farming methods, is of relatively little value, a new assessment of the land value should be made in relation to different water levels in the lake. Future solutions should be aimed at implying that

  • in summer the lake will have a water level very little different from earlier low water level.
  • the high - water peaks will be cut by the regulating dam, and
  • some open stretches of water will be restored by combating Phragmites.

By this new system the natural recourses of the lake, fishing and water power, will be largely restored and could be adjusted upwards if future experience shows that this is economically possible. At the same time the lake could be restored to its position as Sweden´s richest lake for birds and wildfowl.

What should be done to prevent new misfortunes such as the draining of Lake Hornborga.

It is of great interest to observe that the lowering of Lake Hornborga is not the consequence of unlucky chance, caused by one or a few people. Although the long history of the draining of Lake Hornborga has consistently given bitter experience, by its great financial losses, and in spite of the fact that most farmers have been opposed to various draining projects, new people have been appearing continually, with wishful thinking as their main incitement, to organise, permit and realise the drainage projects based on erroneous calculations and ignoring all aspects other than that of drainage pure and simple.

Thus obviously, we always have to take into consideration that some people in position of influence may be inclined to encourage risky drainage projects at all costs.

The following points are suggested as a means to prevent unnecessary destruction of natural waters in Sweden by drainage projects:

    • The legislation pertaining to water should be made equivalent to other legislation. A drainage project should not be granted greater privileges than any other undertaking.
    • No one should be compelled against his will to contribute towards the costs of drainage project.
    • No state subsidies should be granted to such undertakings.
    • The value of a lake or the like , both as surface water and subsoil water, should be assessed by appropriate experts in different spheres before plans are drawn up and a drainage company floated. It should be the duty of the courts to demand a full and substantiated account of value of, for example, fishing and waterpower, the role of the water as a source of supplies of different kinds, its value from the aspects of scientific research and recreation, its importance in the scenery and for the selling value of the surrounding land etc.
    • It shall be the duty of the court to summon and hear every interested party, and to pronounce judgement appropriate to his right in the water.
    • There should be a State body to control that the project is carried out in the way prescribed, and with the power demand that the water be restored to its original condition if the stipulations are not obeyed

  We have an other page that deal with what happened there after.


Le drainage du lac Hornborgasjön en Suède. Un échec économique et ses raisons. Cet exposé traite des essais successifs de drainage du lac Hornborgasjön qui, avec une superficie de 25 km 2 était, il y a encore soixante ans, le lac le plus riche de Suéde pour son avifaune. 

Le dernier drainage fur effectué au cours des années 1902-1962. Il entraîna de lourdes pertes financiéres pour les raisons suivantes : mauvaise évaluation du coût des travaux et des plus-values agricoles, perte totale de I'exploitation piscicole autrefois très riche, perte d'énergie hydraulique, procès civils pendant cinquante ans, législation impropre et nécessité d'utiliser le bassin entier du lac comme réservoir pendant les crues de printemps.

On pense que pour des raisons économiques, il sera nécessaire de remplacer le systéme actuel de drainage forcé par une régulation des eaux moins coûteuse en construisant un barrage pour le contrôle de l'écoulement du lac. Par cc procédé on obtiendrait les avantages suivants : réduction des frais de fonctionnement tout en maintenant le rendement des terres atteintes; niveau d'eau permanent, mais contrôlé récupération de Pénergie hydraulique; restauration partielle de la pisciculture et des populations de gibier d'eau et sauvegarde de cc qui reste de la flore et de la riche faune primitives dont la valeur est inestimable pour les recherches de l'avenir.

Extract from A Directory of Wetlands of International Importance

The Wetlands of Sweden cover approximately 20 % of the national territory and are very varied in type. Lets look at Lake Hornborga located 58'19'N and 13'33'E. Situated between lakes Vänern and Vättern in vestern Sweden in Skaraborg County. Area 6,350 ha.

Degree of Protection

Private and state ownership. The designated site includes two nature reserves. Designated as a Ramsar site on 5 December 1974. (But it does not matter as the autority cannot protect it).

Site Description

Hornborgasjön is a shallow lake, originally 3 m deep, but in which the water level has been lowered five times since 1802. After the last two towerings in 1904 - 1911 and 1932 - 33 the lake was almost completely overgrown by emergent vegetation. By 1933 it had been completely canalised, with inflow being led directly to the outlet, and the lake used to dry up every summer until 1954 when a 1,200 ha area in the north was enclosed by dykes. (Owing to court it should been done 20 years earlier). In 1965 the lake had become overgrown with reed Phragmites australis, slender tufted sedge Carex acuta and willow Salix sp., which led to some experimental clearing of reeds being carried out, and an investigation of the best method of preserving the area for waterfowl was instigated. In 1973 the final report was forwarded to the Government by the Environment Protection Board which proposed that the emergent vegetation be cleared over an area of 1,100 ha and the water level raised. This was approved by the Swedish Parliament in 1977. (But what happened?)

International and National Importance

During the 1970s, breeding waterfowl included all of Sweden's five species of grebe, mute swan (20 pairs), greylag goose, crane, mallard, shoveler, teal, garganey, gadwall, pochard, tufted duck, coot (1,000 pairs), water rail, moorhen, spotted crake, lapwing, redshank, green sandpiper, wood sandpiper, ruff and black - headed gull (8,000 pairs) (Cygnos olor, Anser anser, Grus grus, Anas plaryrhynchos, A. clypeata, A. crecca, A. querquedula, A. strepera, Aythya ferina, A. fuligula, Fulica arra, Rallus aquaticus, Callinula chloropus, Porzana porzana, Vanelhu vanellus, Tringa totanus, T. ochropus, T. glareola, Philomachus pugnax and Larus ridibundus). Other breeding species include grasshopper warbler Locustella naevia (60 pairs), thousands of sedge warbler Acrocephalus schenobaenus and reed warbler A. scirpaceus, and a few pairs of common rose finch Carpodacus erythrinus. Hornborgasjön supports the second largest population of marsh harrier Circus aeruginosus in Sweden (20 pairs), and the only known remnant of the southern Swedish population of hen harrier Circus cyaneus. In the summer a number of osprey, Pandion haliaetus are seen fishing here. The lake is of great importance as a stopover for migrants including mute swan, bean goose, ruff and wigeon. The area is particularly important for crane Grus Grus with 4,000 - 6,000 individuals resting there April - May, some staying on to breed. (The last years 12.000 stay her in April) 

Changes in Ecological Character

The area has been extensively modified by man over the past 200 years. It used to be famous as a testing and nesting site for waterfowl, and it is hoped that after restoration is completed it will once again become one of Sweden's finest waterfowl lakes. Experimental clearing has already had beneficial effects, with little gull, black tern, dunlin and ruff starting to breed here. Restoration is expected to increase the number of ducks in particular. In 1988, representatives of international organisations were invited to Lake Hornborga to receive information about the restoration plan. The Ramsar Bureau's Monitoring Procedure was applied at this time. The Swedish Parliament has recently decided to support the comprehensive plan elaborated by the Environmental Protection Agency. The administrative and judicial processes to obtain permits for raising the lake level have been started. 

Management Practices

Original plans were to raise the water level by 1,5 m. However, in 1986 the Government commissioned the Board of Management to present a detailed restoration alternative which included a (only) 0.8m raising of the water level, but with no or few embankments along the shores. It is believed this will create better habitats for wetland birds compared to the original plans. (They said so). Lake restoration will include clearing vegetation over an area of 1,100 ha, and should be completed by 1987. Public access has to be restricted during April - May when cranes are present. Some potatoes are grown as food for cranes. (No longer, but they permit sludge to be deported on areas protected for resting cranes).

Scientific Research and Facilities

Avifaunal studies have been carried out for along period. More recently there has been extensive research into lake restoration methods, especially on developing methods for reed eradication. Afield station has been established and an information centre was opened in 1986. When lake restoration is complete, Hornborgasjön will provide valuable case study material for restoration of degraded wetlands. (Now they are building another castle close to the lake).

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