Flood in Bremen

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Location of the city of Bremen in the Federal Republic of Germany
Historical storm surges at the main level in Bremen with values ​​above sea level

Floods in Bremen represent a constant danger for the north German city on the Weser . In most cases they result from storm surges in the North Sea , which push the Weser water upstream and prevent it from flowing quickly. In the event of particularly strong floods with an average return time of 700 to 1000 years, large parts of the city are at risk of flooding. In such rare cases, only the Bremen dune is not flooded in the city center .

To protect against the floods, dyke construction measures were therefore taken very early - in earlier centuries. Since 1979, two barrages have prevented any storm surges from flowing into the Weser tributaries Lesum and Ochtum . In the years 1988 to 1993 there was a comprehensive expansion and redesign of the flood protection in Bremen.

Situation on site

The city of Bremen is traversed by the Weser. At 85 percent, large parts of today's urban area are below the mean flood level and are therefore theoretically at risk of flooding and storm tides. However, protective measures are often in place, so that even at the highest flood levels, an area of ​​this size can hardly be completely flooded. In the urban area, the Weser receives two noteworthy tributaries: the Ochtum flows on the left at Unterweser kilometer 12.8, and the Lesum on the right in Bremen-Nord at Unterweser kilometer 17.6. Both tributaries in turn have tributaries. At the Ochtum it is the Varreler Bäke that flows past Huchting in the west , and at the Lesum it is the Wümme , which at the same time forms its left source river and marks the border with Lower Saxony with numerous meanders in the blockland . The right source river is the Hamme (river) , which meets the Wümme at Ritterhude and from there on forms the Lesum with it.

Several water level gauges are operated along the Weser , the data of which is published on the Internet by the Federal Waterways and Shipping Administration :

  • Level Weserwehr Oberweser, Mittelweser, 362,000 km
  • Weser weir gauge Unterweser, Mittelweser, kilometer 362.785
  • Great Weser Bridge gauge, Unterweser, kilometer 0.030
  • Oslebshausen gauge, Unterweser, kilometer 8.375
  • Vegesack gauge , Unterweser, kilometer 17.850
  • Farge gauge, Unterweser, kilometer 26.250
  • Bremerhaven gauge , Unterweser, kilometer 66.64

The water level at the Great Weser Bridge in the city center is one of the most important. It is located on the left side of the Weser on the Teerhof peninsula on the street Herrlichkeit. Although its data cannot be regarded as generally binding for all banks of the Weser in Bremen, they are usually set as guidelines. If there are deviations from the mean flood, the respective values ​​announced in Bremen apply to this level. The population is informed about these deviations in the radio news and on the Internet. Since in most cases the high water is determined by the tide , the technical term is tidal high water (Thw). In recent times the mean flood has been 2.56 meters. The mean low water (mTnw) is 1.6 meters below sea ​​level . The mean tidal range is thus 3.88 meters. At this level, the mean flow rate at mean tide is 327 cubic meters per second. In extreme cases, it can drop to 180 cubic meters, but it can also increase to 1200 cubic meters.

There are other levels at the Lesum and at the Wümme:

  • Wasserhorst gauge, Wümme, kilometer 2.255
  • Borgfeld gauge, Wümme, kilometer 0.265
  • Level Lesum Barrage inside, Lesum, kilometer 1.65
  • Outside Lesum Barrage gauge, Lesum, kilometer 1.65

For the flood forecast, which is carried out by the Federal Maritime and Hydrographic Agency (BSH) , for example , the data from some gauges are used, to which the gauge in Bremerhaven belongs.

Cause of flood

The course of the Weser and, above all, its bed volume (based on the width and depth of the river bed) changed over the centuries as a result of structural engineering work. It was initially a meandering river near Bremen with numerous shoals and islands, but it has been largely straightened and deepened under the direction of Ludwig Franzius, mainly since the Weser Correction . These corrective measures, which included a five-meter deepening and bank reinforcements, began at the tide line in Bremen and extended to the mouth of the river. In addition, the mean flood was now pushed more effectively into the interior of Bremen, which resulted in an upswing in the port there. On the other hand, as a result of the straightening and fortifications, the river lost most of its natural flood areas. This gave the water masses less leeway due to the now narrower width of the river. The tidal range, which was only about one meter around 1900, increased to several meters as a result of the expansion measures.

The meteorological and hydrological conditions in the natural areas further upstream, the low mountain ranges, are to be regarded as decisive factors for the Weserb inland floods in Bremen . These are on the one hand precipitation and on the other hand the snowmelt in spring. The inland flood is defined by the discharge in cubic meters per second at the Intschede gauge , as this is decisive for the city located downstream.

Similar to the Rhine in Cologne or the Elbe , for example, the Weser can be assigned to a pluvio-nivalen (rain-snow-fed) discharge regime . As a result, the floods in the Hanseatic city increase at the beginning and at the end of each winter. From autumn to early winter, heavy rainfalls in the source regions of the Weser and its source rivers, but also further downstream, cause the current to swell strongly. In the following weeks, precipitation that falls in the mountains is bound in ice or snow and thus lasts through the winter. When the snow melts in spring, mostly in February and March, due to rising temperatures, the stored water is released and pours into the rivers. The soils, which are often still frozen, are unable to absorb overflowing water. Since new precipitation can come in addition to the meltwater at this time, it can usually be expected that the spring floods will accumulate higher than those in autumn.

Storm surges in the North Sea are another flood hazard for Bremen. Similar to inland floods, they usually occur in the months of November to March. This leads to massive flooding as hurricane storms push the North Sea water into the mouth of the Weser funnel, prevent its own drainage and damming it up. The flood wave rolls upstream from Bremerhaven and reaches the city of Bremen within about three hours. The heavily narrowed and straightened Weser can absorb little energy from the waves in the urban area, which is why high water levels develop very quickly. In addition, there is a risk that the storm surges will also press into the Ochtum and Lesum, swell them and cause them to overflow, which would flood the urban area from three sides at the same time. A particularly dangerous situation is the coincidence of storm surge and inland flood in the city of Bremen.

Historical floods

The potential danger from flooding is measured by the frequency and the mean water levels. For this purpose, series of measurements are initially formed over a period of ten years. In connection with the consideration of climate change, historical floods have become increasingly important. The term annuality is used in technical jargon for the probability of a certain flood level occurring .

List of floods in Bremen (inland floods
are highlighted in gray)
year Value at the Great Weser Bridge gauge above NN Discharge in m 3 / s Annuality
1685 650 - 500 annually
1699 710 - 1000 annually
1739 600 - 100 years
1827 729 - -
1830 680 - -
1845 771 - 1000 annually
1880 780 - -
1881 - 4,200 600 annually
1881 780 - 1000 annually
1906 491 - 5 years
1946 580 - 50 years
1962 541 1,100 20 years
1976 532 - 20 years
1981 - 2,650 45 years
1994 543 - 20 years
2007 508 - 10 years
2013 525 - -
Medium flood 228
Medium low water - 160

1717

The flood, which hit the German North Sea coast on December 24th and 25th, 1717 and was given the name Christmas Flood because of the date , was caused by the worst storm surge of the 18th century. The then city of Bremen itself was spared from the floods, as they broke in the variously ramified river course of the Lower Weser. However, there were severe floods in areas that were then still independent municipalities and are now part of Bremen. The storm surge in the Blumenthal district completely destroyed a dike and two more dike breaches were recorded in Rekum . The water masses pressed into the mouths of the Weser tributaries Ochtum and Lesum. As a result, on the right side of the Weser, all areas to the left of the Lesum and Wümme were flooded, including the Werderland, the entire blockland and the town of Walle . On the left bank of the Weser, the floods of the Ochtum inundated the Lower Land lowlands with the villages of Strom and Seehausen . Since Bremen was not affected, the Hanseatic city took full part in the relief efforts.

March 1827

At the end of February 1827, after a short but very severe winter, a strong thaw set in, and from the beginning of March the Weser began to rise in the Bremen city area. While their level on the 2nd of the month was 2.40 meters above sea level, it rose to 4.00 meters by the evening of March 4th and later to 7.29 meters. On the night of March 5th to 6th, the flood streamed into Neustadt via the Kleine Weser . The Buntentorsteinweg and many other streets in this area were completely flooded. On the morning of March 6, between 9 and 10 a.m., the Weser dykes on the left side broke both above and below the village of habenhausen , which is now a district of Bremen. There was widespread flooding there. In the afternoon, the Eisenradsdeich on the right bank of the Weser gave way in two places, and the Weser water washed into the Ostertorvorstadt , where numerous houses and the stone gate bridge over the Dobben canal were destroyed.

March 1830

The flood of 1830, which caused the Weser to rise to 6.8 meters above sea level, was the heaviest and most lossy inland flood that has plagued Bremen in its recent history. Almost all large marsh meadows - the Werderland, the Blockland, the Hollerland , the Vieland with Niedervieland and Obervieland and the Mahndorfer Marsch - as well as numerous villages that belong to the city today were flooded.

prevention

The winter of 1829/1830 was unusually long and severe and the soil on both sides of the Weser was deeply frozen. It was foreseeable that they would not be able to absorb any meltwater if the thaw set in quickly. In addition, it was feared that breaking ice barriers could increase the flow of the Weser and its tributaries. For this reason, the Senate appointed experts for both banks to manage and coordinate the dike defense and any relief operations for people. On the left bank of the Weser, this task was taken over by the Dutch building officer Jacobus Johannes van Ronzelen , Lieutenant Sattler and Conducteur Findorff.

As one of the preventive relief measures, twelve ships were made available to rescue people and transport goods required for dike protection.

course

As forecast, the thaw set in at the end of February, on the 26th of the month, and, combined with heavy rain, caused the snow to melt quickly. The following day, the ice sheet on the Weser, which was up to 60 centimeters thick, was lifted and broken through by the rapidly rising water, which quickly led to temporary barriers.

On the morning of March 1st, the Katrepeler dyke broke on the Wümme, so that the water flowed into the wide and almost uninhabited meadows of the Holler and Blockland . The break could be closed again in a relatively short time at noon on the same day. During the day, the Weser rose to 6.80 meters above sea level at the Great Weser Bridge.

The following night, the helpers managed to seal numerous leaks on dykes in the city with the help of equipment carts that had been loaded with boards, hand rams, alder stakes, dung and straw. These successes were recorded, for example, on Brautstrasse, in Neustadt and on the Kleine Weserbrücke.

On March 2, around 10 a.m., the water from the Weser broke through the dike in two places in Hastedt and tore away the homes of 27 families. Six other houses and two outbuildings were irreparably damaged. Four women and six children fell victim to the flood in Hastedt. The dykes also gave way in the neighboring district of Mahndorf. Pastor Hollmann, the pastor of the Evangelical Lutheran parish of Alt-Hastedt at the time, noted in his written memoirs: “Since the water penetrated into all the houses near the parish apartment, and only these remained free, 60 people fled who lived there for a few weeks. "

A Vogt named Holscher reported from the Neustadt side that the habenhausener dyke was still safe, although it had water running through it in some areas. Van Ronzelen decided to take a look at the dike and found that it was extremely endangered. He then ordered several workers to secure it, but at 10 p.m. the dike began to slide and on March 3 at around 3 a.m. it broke over a width of 23 meters. This break widened to 120 meters within 20 minutes. As a result of this dike breach, large parts of both the Upper and Lower Lands were flooded. The floods were intensified by the fact that the Weser dike and in Stuhr an Ochtum dike broke in the Dreye municipality upstream . The water released there made its way across the flat fields to the Vielande . Almost the entire Neustadt was under water, and the Senate decided to send off the prepared boats: two were sent to the Buntentor, two to the Hohentor, three to the Steinweg, two to habenhausen and one to Strom.

In the latter village in particular, the situation was sometimes dramatic, as the farms were surrounded by two tidal waves at the same time: on the one hand, from the one that came from the dike breach in habenhausen, and on the other, from the other side, since the Ochtum had overflowed its banks. As a result, Brinkum , Warturm, Huchting , Seehausen and Grolland, which at that time was still predominantly agricultural, were flooded. Since the Brinkumer Heerstraße, which led south out of Bremen, was impassable for several days, the Bremen merchants set up a ferry service in the flooded area, which transported trucks from Warturm to Brinkum and thus maintained Bremen's trade with the inland.

The consequences of this inland flood could still be seen in the Bremen cityscape for months, including the fact that the water remained on the meadows and fields until summer, but also partly in the villages. It was not until autumn that the habenhauser dyke was completely closed and covered, as it was not previously possible to procure the clay required for it.

December 1880

Badge on the police station on Parkallee

In December 1880 there were exceptionally intense rains on the upper reaches of the Wümme , which caused the river to swell very strongly. The former Wümmedeich in the almost uninhabited blockland , the area on the left side of the river in Bremen, was very narrow but steep. The Wümme was quickly dammed by its tight turns, washed the dike fortifications from their backs facing the river and penetrated into the soil of the dike. Shortly afterwards the water emerged again as a small rivulet at the foot of the inland embankment on the land-facing side. Within a few days, the inland embankment slipped along its entire length from the Burgdamm district in the west to the Borgfeld district in the east. Soon the top of the dike was so narrow that the water masses were able to push it in. This dike breach occurred on December 29th near the Kropp homestead and washed out a hole eight meters deep.

As a result of the break, the entire block land with an area of ​​more than 30 square kilometers and large areas of the districts of Findorff and Schwachhausen were flooded. It took a good three months before the water had completely withdrawn.

Memories of this flood disaster, which was one of the largest in terms of area in Bremen, can still be found in several places in the city. At the Parkallee police station at the Bürgerpark , for example, there is a high water mark showing the water level at that time. Something similar can also be found in the Bürgerpark itself and on the outer wall of a house on Klattendiek Street in the Horn-Lehe district . A carved wooden panel was set up at the site of the dike breach in 1880, which is now between the farms Niederblockland 14 and 15. The eight meter deep hole is still preserved at the foot of the inland embankment of the dike and is called Niederblocklandsee.

February / March 1881

The flooded Schwachhauser Chaussee in March 1881

While the water from the last flood was still on the fields in the north of the city, the south was hit by a new flood in the spring of 1881. The Weser swelled very quickly due to a strong thaw. At the Intschede gauge, it reached a flow rate of 4200 cubic meters per second, which corresponds to the highest Weser flow rate ever measured to Bremen and which is likely to occur only once in 600 years.

The river broke through the left-hand dike near Thedinghausen on February 19 . The Ochtum dykes were unable to hold back the water masses advancing in a north-westerly direction and were largely flooded. As a result, in addition to many other villages, the municipalities of Stuhr , Varrel, Moordeich (today both belong to Stuhr) and Huchting as well as the entire Niedervieland were flooded. In Huchting the water was up to 90 centimeters high in the streets. A good three weeks later, on March 13, several sections of the dike on the left of the Weser gave way down from Hoya . This intensified the tide. Meanwhile, in Bremen even the Weser ran over its right-hand dyke and streamed into both the city ​​center and the Bürgerpark . According to eyewitness reports, the old town, located on a dune and thus slightly higher than the surrounding area, protruded like an island from the surface of the water. On the wall of the Concordenhaus in Schnoor there is a mark of the historical high water level from March 13th.

This inland flood flooded a total of 36,000 hectares of land and was the last complete flood of the Ochtum lowlands from Hoya to the mouth of the river. The water level of this high tide is also marked on the already mentioned high water mark at the Parkallee police station.

Floods in the 20th century

March 1906

The storm surge of March 13, 1906 was one of the worst that Bremen has ever hit. It dammed the Weser at 4.91 meters above sea level and thus 2.63 meters higher than during a normal mean flood. However, the main danger in this flood did not come from the Weser river, but from its left tributary Ochtum. Because the Weser water pressed into it, prevented its drainage and even let it flow backwards at times, the Ochtum finally overflowed its banks, which resulted in extensive flooding of the villages of Hasbergen (today a district of Delmenhorst ), Strom , Huchting, Grolland, Varrel and also resulted in Stuhr. A total of 33 square kilometers of land was flooded on this March day.

February 1946

High water marks on the Weser promenade / height Wilhelm-Kaisen-Brücke

The storm surge of 1946 hit Bremen at one of the most inopportune times. After the Second World War , the city ​​was still largely in ruins. The food supply for the needy population was not yet fully guaranteed everywhere. Particularly in the winter months there was often a shortage and, as a result, hunger among the people, some of whom lived in makeshift accommodation or in allotment houses.

On February 11th the flood broke in. The left bank of the Weser was particularly badly affected, where countless parcels were destroyed and the people lost their last belongings when the Weser overflowed its banks in some places in the Lower Vieland.

The hurricane blowing from the north-west pushed the Weser water up to 17 kilometers into tributaries of the second order, such as the Varreler Bäke , a tributary of the Ochtum. Its upper course is called Klosterbach . This broke in the afternoon between the villages of Blocken and Groß Mackenstedt (both now part of Stuhr) through the low and unsecured dikes. Although it is a small watercourse under normal conditions, the storm surge through the breach of the dyke flooded the Ochtum lowlands from Kladdingen (now a district of Stuhr) to the mouth of the Ochtum. Numerous villages, for example Blocken, Moordeich and Stuhr, were under water. Thus, the Lower Vieland was hit twice again: by the dike breaches on the Klosterbach and by the Weser flood.

In Bremen, this storm surge, which caused the Weser to rise to 5.80 meters above sea level and thus 3.52 meters higher than the mean flood, claimed two lives.

December 1954

Between December 19 and 23, 1954, a series of storm surges led to floods in the area of ​​the Ochtum lowlands, the Woltmershauser- and Rablinghauser Grodens and the Stadtwerder. The Hammeschleuse in Ritterhude will be flooded, as will the areas on the Lesum and in Bremen-Farge, Bremen-Blumenthal and Vegesack, which were not yet protected by dykes and storm surge walls. In Bremen-Huchting, the areas on Wardamm must be evacuated as a precaution. In many places the crests of the dykes that have not yet been raised and reinforced are reached. It is only through fortunate circumstances that a catastrophe does not occur.

February 1962

- see also map of the flooded areas: -

The storm surge on the night of February 16-17 , 1962 , triggered by the hurricane Vincinette, also hit the city of Bremen. 50 square kilometers were flooded within a few hours. This corresponds to about 15 percent of the urban area.

On the morning of February 16, there was already a hurricane storm in the Hanseatic city, and the midday flood rose 1.93 meters higher than normal at the Great Weser Bridge in the city center and thus reached 4.21 meters above sea level. At first, the local authorities expected the city to get off lightly. This hope stemmed from the fact that a few months earlier inspectors had checked the dikes and sealed off critical areas, so that it was assumed that there was no great danger. 60,000 sandbags were stored in the city , a number so high that Bremen could even afford to send another 80,000 to Otterndorf and Stade and 10,000 to Bremerhaven . It was believed that these places would be worse affected by an eventual flood.

Initially, the main focus of the Bremen-based company was on the considerable storm damage. For example, in the Gartenstadt Vahr district, more than twelve pent roofs tore off and blew onto the street, injuring some people. For this reason, the fire brigade decided in the evening to close most of the residential area.

At about the same time, the first allotment garden areas near the Weser began to be evacuated, as the intensifying hurricane meant that the night flood could rise significantly higher than the midday flood. These assumptions were confirmed. During the night floods, the Weser reached a height of 5.41 meters above sea level. It was 3.13 meters higher than at mean high tide. As hoped, the dykes in Bremen withstood the pressure of the storm surge. However, they were not sufficient in their height. On February 17th at 12:45 a.m., the Weser flooded the meadows of the rural district on the left and the street village of Strom in the Niedervieland. A little later the houses were all under water.

At 1.30 a.m., several dikes were flooded almost simultaneously: The Weser flooded over the Hasenbüren dike and flooded the villages of Hasenbüren and Seehausen in the Seehausen district on the left . Also in Hasenbüren the Ochtum overflowed its banks and in the northern part of Burglesum the Lesum streamed over the Lesumbroker dike. This resulted in a flooding of the Werderland , the Blockland , Lesumbroks, parts of the residential areas in the district of Burglesum and even the Wümmewiesen , which is 26 kilometers as the crow flies from the mouth of the Lesum, through the floods leading to the Lesum or its source river Wümme .

The floods in Ochtum and Lesum resulted from the fact that - as with almost every storm surge - the Weser water was also pressed into the tributaries. Big problems arose especially at the Ochtum. Although it had already overflowed its banks in Hasenbüren, it still carried far too much water further upstream for its course, which was delimited by narrow dikes. As a result, it also flowed uncontrollably over the fortifications and flooded the entire Niedervieland, the southern Obervieland , as well as large parts of Huchting. In Huchting, next to the roofs of the houses, only the embankment protruded from the waters. While the Ochtum flood hit the east of Huchting, the Varreler Bäke flooded the western part, as it was also a tributary of the Ochtum.

But the Weser not only stepped across its dykes in Hasenbüren, but also on its left banks in Woltmershausen , Rablinghausen and in the Woltmershauser Vorfeld, so that the water there stood high on the houses. Several allotment garden areas as far as Warturm were completely destroyed, which meant the loss of several hundred houses. Stadtwerder , located further up the Weser, was also under water, as was the Suhrfeld area, which is connected to the north end of today's Karl Carstens Bridge in the east .

Bremen-Nord was also badly affected by the effects of the night storm surge . In Vegesack, for example, the Weser ferry Willy capsized and sank as a result of the currents caused by the flooding . In addition, more than 2000 cubic meters of water flowed into the Farge power plant near the Weser , which could only be pumped out after several weeks.

The next morning the storm subsided somewhat and the midday flood of February 17 only rose to 2.23 meters above mean high water, i.e. 4.51 meters above sea level.

The storm surge of 1962 killed seven people in Bremen. They died in Rablinghausen, Huckelriede and Woltmershausen. During the night around 4,000 disaster relief workers were on duty in Bremen, including a good 1,000 soldiers from the German Armed Forces. They had to rescue 453 people from rooftops and take care of the more than 1,000 homeless people who had lost their homes or apartments during the flood. During the storm surge, 2000 tons of sand were transported in the Hanseatic city independently of the sandbags in order to hold the dikes in the Blockland, Grolland, Huchting, Lesum and Ochtum rivers. The property damage from the flood amounted to a rounded 50,000,000 German marks .

February 1967

On the night of February 23rd to 24th, 1967, the areas in front of the main dykes were flooded by the storm surge caused by the Adolph Bermpohl storm. At the Ochtumdeich in Bremen-Strom , flooding of the dyke at the level of the Stedinger Bridge can only be prevented by the massive installation of sandbags.

January 1976

Unlike in many other areas on the German North Sea coast, the storm surge of January 3, 1976 in Bremen was no higher than it was 14 years before. Nevertheless, triggered by the Capella storm , which reached top speeds of 128 kilometers per hour in the Hanseatic city, it led to massive flooding. The first warning of the flood was issued at 10:55 a.m. with a request to the population to prepare for a possible evacuation. At around 11:30 a.m., the promenade on the Osterdeich on the right bank of the Weser was flooded and the Weser ferries stopped working. Three hours after the first warnings, the first dike in Bremen, the summer dike on the left side of the Lesum in the bend in the river at the Burger Bridge, gave way under the pressure of the water pushed into the Weser and its tributaries by the hurricane. The dike was deliberately not raised with sandbags so that the water could drain into the intended overfill areas. According to the plans, it poured into the blockland. At 3:05 p.m., the disaster relief workers recorded the water from the Weser spilling over the Deichschartweg and a little later flowing into the Werdersee. However, the flood channel was not developed enough for the unexpectedly large amounts of water, so that almost an hour later the entire Stadtwerder and the area in the Suhrfelde were under water. Numerous people had to be brought to safety.

While the Weser reached its maximum value of 5.32 meters above sea level at the gauge, the authorities prepared to blow up the embankment to the Neustadt port with a ton of trinitrotoluene . The Niedervieland behind it was designated as an overfill area, but the dam looked like a dike: It kept the water on the side facing the Weser and could possibly have diverted it into the densely built-up Woltmershausen . Since the builders had foreseen this, blasting chambers were built in when the railway embankment was built. The demolition had to be decided in the last instance by the President of the Senate Hans Koschnick and two senators, as the port would then have been cut off from any rail connections for a good month. Ultimately, it didn't need to be blasted because the Rablinghauser Groden broke at 4:40 p.m. and the water spilled into the Niedervieland as planned. The up to six meter high winter dikes withstood this load.

March 1981

Today's " Neue Weser " nature reserve is the remnant of the 1981 flood channel

In mid-March 1981, an inland flood in Bremen caused the worst flooding since 1946. The Upper Weser carried 2650 cubic meters of water per second, which could not flow sufficiently into the Lower Weser because one unit of the old Weser weir was defective. The water broke above the weir on the left bank of the river through the dike and flooded the northern part of the habenhausen district. Although this was designated as an overcrowding area, it was occupied by numerous allotment garden areas. Unfavorable dyke routing threatened a break-in into the residential area, which could, however, be averted by up to 200 helpers who built a relief dam. Finally, the water flowed back into the Weser through another breach of the dike and caused considerable damage to its banks. In the course of this breakthrough in the Weser , an area of ​​70 hectares was flooded and around 150 small houses were destroyed. As a result of the flood, which led to a donation campaign that was unprecedented in the state of Bremen, the flood protection of the city was fundamentally reorganized. In addition to the construction of the new Weser weir, the Werdersee was also lengthened, which was supposed to serve as a collecting channel for storm floods, but which proved to be useless during the 1981 flood. The remains of the flood channel from 1981 are now designated as a nature reserve.

January 1994

On January 28, the high tide reached a value of 5.43 meters at the Great Weser Bridge gauge, two centimeters higher than the 1962 storm surge. However, it must be taken into account that the barrages at Hunte, Ochtum and Lesum were closed and the running water could not get into the tributaries. For example, the Lesum barrage was closed when the water level reached 2.70 meters. This led to an increase in the measured water level. Thanks to the well-functioning forecast system of the water management office in Bremen , the necessary measures could be taken at an early stage. Several hours before the highest water level was reached, the police had triggered a disaster alarm.

Floods in the 21st century

November 2007

On November 9th, hurricane Tilo caused severe flooding in the Bremen city area. The authorities spoke of a severe storm surge. The right bank of the Weser was hit hardest by the flood.

As a result of the Tilo hurricane, the Werdersee overflowed its banks on November 9, 2007 , looking north to the Bremen-Hastedt power station

Although no people were injured in Bremen during this storm surge, there was some serious damage to property. The Weser rose to 5.08 meters above sea level at the Weser Bridge in the center of the city at 2:35 p.m. The Martinian pier and the Weser promenade were flooded. In addition, the Weser water ran into a pedestrian underpass near the St. Martini Church and made the path impassable for several hours. The floods stretched upstream on the right bank of the Weser to the Karl Carstens Bridge . So the auenartigen green areas between the center and the example were Weserstadion flooded, in the north of the dismantled a street Osterdeich be limited. In front of the stadium the current reached twice its usual width.

The Pauliner March was also affected. Numerous allotments were there up to 70 centimeters under water. At a few hundred meters further flussaufaufwärts located Weserwehr no flow gradient was observed between upper and lower Weser.

In the right-hand northern districts of Blumenthal and Vegesack, but also on the banks of the left-hand Neustadt , it took the fire brigade to tow more than a dozen cars that had been parked incorrectly and hit by the water. In Vegesack, where numerous streets were deeply under water, the effects of the storm surge were particularly impressive because some of the floods were up to two meters high on the house walls. In the port area of ​​the district, however, most of the buildings have security doors and windows made of armored glass, which prevent the water from penetrating.

By 5:30 p.m., the level had dropped so far that there was no longer any greater danger. However, the mean low water, which is usually 1.6 meters below sea level, did not come close to this depth, as the still strong and persistent storm held the water at a level slightly above sea level. Fears have therefore been voiced that, in conjunction with the night floods, there would be another flood. Fortunately, this did not happen.

In the evening regional news program buten un in on Radio Bremen TV , the managing director of the Bremischer Deichverband on the right bank of the Weser , Wilfrid Döscher, spoke about the flood:

"[...] If you want to put that in a ranking, it was actually number four on the hit list - so we experienced the fourth-highest storm surge ever recorded in Bremen today. [...] "

December 2013

The storm Xaver at the beginning of December 2013 led to record water levels on the North Sea coast, so that the Weser was also affected. In the city of Bremen on December 6, 2013, two consecutive storm surges reached water levels that were among the highest in 130 years. At 05:45 am, the water level at the Great Weser Bridge was 5.25  m above sea level. Measured above sea ​​level - that is just under three meters above mean flood. The flood at 4:47 p.m. reached 4.92 meters, exceeding the storm surge of 1906. This flooded the Weser weir in Hastedt , and the new Weser power station in Bremen was unable to generate electricity for a few hours for the first time since it went into operation because of the lack of a gradient .

October 2014

On October 22, 2014, the foothills of Hurricane Gonzalo led to increased water levels in the North Sea and thus also in the Weser. At 1:10 p.m., a water level of 4.66  m above sea level was reached at the Große Weserbrücke gauge . NHN measured. Due to the weather situation, an increased water level was expected the day before.

Flood protection

Flood protection has a long tradition in Bremen. This is mainly due to the fact that the city's residents have had to deal with flooding since the city was founded around 780. The first obvious protective measure taken by the early settlers was that they built their huts on a high dune line on the right bank of the Weser, today's Bremen dune . Even the highest tides did not wash over it.

The systematic embankment of the settlements began around 1275. The first documented embankment of a dike, however, dates from 1374. For a long time, it was simply known as the old dike . In 1433, the first Bremen dyke association, the so-called dyke association of the four countries, was founded. Forty years later, the first general dike regulations were written down, which lasted for several decades. In 1850 it was updated by a new version, which resulted in two large main dike associations being formed.

Nowadays, two main dike associations are responsible for the dike and the maintenance of protective measures. The Bremische Deichverband, founded in 1937 on the right bank of the Weser, has an area of ​​responsibility of 22,000 hectares. The association maintains around 645 kilometers of main watercourses and 96 kilometers of state protection dikes. The counterpart on the left bank is the Bremische Deichverband on the left bank of the Weser . This is responsible for bodies of water with a total length of 145 kilometers and was founded in 1947. The length of the dyke administered by him is 63.5 kilometers.

For more information on the history of flood protection in Bremen: → Main article: History of the Bremen dyke system .

Numerous areas of the city were advertised as flood areas , i.e. as alternative and relief areas for possible floods. These areas include, for example, the park to the left of the Weser an der Ochtum, the 375 hectare nature reserve Ochtumniederung in Huchting, the Weseruferpark Rablinghausen with adjoining allotment garden areas, the Borgfelder Wümmewiesen, the 148.5 hectare nature reserve Untere Wümme, the one east of the ditch Deichschlot Marschwiesen in the Oberneuland district , the southern areas of the Mahndorfer Marsch, the habenhauser Weserwiesen, parts of the Stadtwerder , a right bank of the Weser from the ports to Blumenthal and the Pauliner Marsch. This is a green area in the Weserbogen, which is delimited by the Osterdeich in the north, the Weser in the south and the Karl-Carstens-Brücke in the east and contains sports fields, lots and a restaurant.

The overcrowding areas in Bremen

An essential aspect of Bremen's flood protection at the beginning of the second half of the 20th century is the contiguous watercourse of the Kleiner Weser and Werdersee . While the former had existed for centuries as a small left arm of the Weser, the Werdersee was only created as an extension to the east in the years 1953 to 1960. It was hoped that in the event of a dike breach on the Weser, it would absorb flood water before it reached the residential areas of Neustadt . After the lake had proven to be almost ineffective in its protective function during the floods of 1981, since it was able to protect Neustadt from storm surges, but not habenhausen from inland floods, a large-scale redesign was decided. The body of water was lengthened by another 1.07 kilometers beyond the Karl-Carstens-Bridge, so that it now extends almost to the Oberweser in the east and is connected to the Kleiner Weser in the west. In addition, the dykes were revised in this area.

In 1959, the Hanover- based Franzius Institute carried out an extensive study of the flood hazard for Bremen. The possible effects of storm surges and inland floods on the environment were also analyzed. The determined results were significantly included in the determination of new protection systems. From 1971 to 1974 the Lesum barrage was built on the lower reaches of the Lesum in the Burglesum district , about 1.65 kilometers below the confluence with the Weser. In addition to a lock chamber, it has three flow units. However, it could not be put into operation until 1979, as the Ochtums barrage and the Huntes barrage were to be completed beforehand. It was feared that the water levels could become uncontrollable if one barrier were closed independently of the others. The Huntes barrage in Lower Saxony does not serve to prevent floods in Bremen, but this is the case with the barrage on the Ochtum, which is also located in Lower Saxony. It is located 384 meters above the estuary, has a lock chamber and two locking units. Both barrages serve to prevent the Weser water from being pressed into the tributaries during storm surges and possibly causing them to overflow their banks. They have a barrier height of 6.60 meters above sea level. The Lesum barrage, which primarily protects the blockland and the residential areas in Burglesum, shortened the dykes of the Lesum and its source rivers, which are at risk of storms, by 38 kilometers. From Bremen's point of view, the Ochtums Barrage is responsible for the security of the Niedervieland, Woltmershausen and Huchting areas. Its construction made it possible to reduce the length of the flood-endangered Ochtum dyke by 22 kilometers.

Nowadays the city of Bremen is secured by flood protection systems - earth dikes, barrages, protective walls and drainage channels - with a total length of 155 kilometers. Of these, 87 kilometers above and 68 kilometers below the barrages are the Ochtum and Lesum. The dykes in Bremen have heights that vary between 7.20 meters above sea level in Bremen-Nord and 10.50 meters above sea level in habenhausen. This is due to the fact that during storm surges in the northern parts of the city, where it is already very wide, the Weser does not rise as high as it does further upstream, where it is dammed up by the narrowing river bed. The individual flood protection systems are either owned by the municipality of Bremen, the state or the two dike associations. The annual costs for flood protection in 2003 for the Bremischer Deichverband on the right bank of the Weser amounted to 1,500,000 euros and for the Bremischer Deichverband on the left bank of the Weser to 760,000 euros, so together to 2,260,000 euros. The city of Bremen took over 1,000,000 euros of this.

swell

Web links

Commons : Floods in Bremen (state)  - Collection of images, videos and audio files

Individual evidence

  1. Level selection via table. Retrieved April 26, 2014 .
  2. WSV water level data for the Great Weser Bridge. Retrieved April 26, 2014 .
  3. http://www.pegelonline.wsv.de/gast/stammdaten?pegelnr=4990010
  4. https://www.pegelonline.wsv.de/webservices/zeitreihe/visualisierung?parameter=Wasserstand%20Rohdaten&pegelnummer=4910050
  5. Weser Courier . No. 300, December 24, 1954: The great Christmas flood AD 1717
  6. Black Forests . (2003), p. 897
  7. a b c d e Weser Courier. No. 139, June 15, 1973, page XXV: When the great floods came in Neustadt ...
  8. ^ Deichverband on the right bank of the Weser: Map of the flooded areas in Bremen 1962
  9. a b c Weser courier. No. 42, February 19, 1962, p. 3: Seven Bremen victims of the storm surge.
  10. a b c Weser courier. No. 42, February 19, 1962, p. 4: More than 1000 homeless.
  11. a b Weser courier. No. 3, January 5, 1976, p. 10: The feared flood disaster did not materialize on the Lower Weser.
  12. Weser Courier. March 17, 1981: Does the winter dike stop at habenhausen?
  13. https://www.pegelonline.wsv.de/webservices/zeitreihe/visualisierung?parameter=Wasserstand%20Rohdaten&pegelnummer=4910050
  14. http://www.kreiszeitung.de/lokales/niedersachsen/niedersachsen-erste-sturmflut-herbstes-nordseekueste-erwartet-4191470.html
  15. Association area. Bremischer Deichverband on the right bank of the Weser, archived from the original on February 22, 2012 ; Retrieved February 18, 2012 .
  16. ^ History. (No longer available online.) Bremischer Deichverband on the left bank of the Weser, archived from the original on June 4, 2012 ; Retrieved February 18, 2012 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Dressing systems. (No longer available online.) Bremischer Deichverband on the left bank of the Weser, archived from the original on June 4, 2012 ; Retrieved February 18, 2012 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.deichverband-bremen-alw.de  @1@ 2Template: Webachiv / IABot / www.deichverband-bremen-alw.de
  17. Flood protection measures. Bremischer Deichverband on the right bank of the Weser, accessed on March 13, 2020 .
  18. Operation and maintenance. Bremischer Deichverband on the right bank of the Weser, accessed on March 12, 2020 .
This article was added to the list of articles worth reading on June 8, 2008 in this version .