Flood protection on the Lower Rhine
Flood protection is an important task of all regional authorities in the flood area on the Lower Rhine in the context of services of general interest . Since the beginning of the industrial revolution in Germany , the number of residents in the Lower Rhine area has grown significantly. Over 4.3 million people live in the ten large cities on the Lower Rhine:
| Rhine km | Urban parish | Ewz. | Section of the Rhine | Embankment of the city center |
|---|---|---|---|---|
| 655 | Bonn | 315,000 | Lower Rhine | L. |
| 688 | Cologne | 1,013,000 | Lower Rhine | L. |
| 699 | Leverkusen | 161,000 | Lower Rhine | R. |
| 740 | Neuss | 153,000 | Lower Rhine | L. |
| 743 | Dusseldorf | 578,000 | Lower Rhine | R. |
| 762 | Krefeld | 241,000 | Lower Rhine | L. |
| 777 | Duisburg | 497,000 | Lower Rhine | R. |
| 884 | Nijmegen | 161,000 | delta | L ( Waal ) |
| 1000 | Rotterdam | 586,000 | delta | R ( Nieuwe Maas ) |
| Arnhem | 143,000 | delta | R ( Nederrijn ) | |
| Utrecht | 283,000 | delta | R ( Oude Rijn ) | |
| Suffer | 118,000 | delta | R (Oude Rijn) |
Eckhard Uhlenberg (CDU), NRW Environment Minister ( Rüttgers cabinet ) from June 24, 2005 until after the NRW state elections on May 9, 2010 , stated:
The obligation to protect against floods is not regulated by law in North Rhine-Westphalia! They are not assigned to the state, the municipalities, or individuals. On a voluntary basis, affected citizens can join forces in water associations (dike associations) and issue statutes.
Directive 2007/60 / EC on the assessment and management of flood risks came into force on November 26, 2007 ; With the amendment to the Water Resources Act on March 1, 2010, it was implemented in national law (see also the consequences of the federal reform ). In July 2011, the NRW Ministry of the Environment presented an 84-page report on the situation in NRW. 17 pages of the report (pp. 22–39) deal with the situation on the Lower Rhine.
NRW Environment Minister has been Johannes Remmel ( Cabinet Kraft I , Cabinet Kraft II ) since July 15, 2010 .
The Lower Rhine and its tributaries
On the Lower Rhine (Germany), some relatively small tributaries flow into the Rhine. There are (enumerated downstream from Bonn) the Sieg (km 659.3), Wupper (km 703.3), Erft (km 735.5), Ruhr (km 780.2), Emscher (km 797.7) and Lippe (km 814.5). All except the Erft are on the right bank of the Rhine.
Regardless of their size, they are important when the Rhine floods: then the water level in the mouth of these tributaries also rises. Their banks must therefore also be protected with dikes in their estuary.
The tributaries feed relatively little water into the Rhine; nevertheless, their inflow can increase a Rhine flood somewhat.
|
Tributary (section, arm) mouth / transition: |
MQ (mean outflow) (m³ / s) |
EZG (single building) (km²) |
Height max. of the EZG (m) |
Height Munich dung (m) |
Length (km) |
Length (H) (km) |
Length (L) (km) |
Up km ship journey |
|---|---|---|---|---|---|---|---|---|
|
Victory from the right in: Middle Rhine 
|
53 | 2,856.9 |
675.9 ( Jagdberg ) |
45 | 155.2 | 156.7 | 156.7 | 659.3 |
|
Ruhr from the right in: Niederrhein
|
81.6 | 4,485.4 |
843.2 ( Langenberg (Rothaar Mountains) ) |
20.2 | 219.3 |
220.3 |
221.8 | 780.2 |
|
Lippe from the right in: Niederrhein
|
45 | 4,887.7 |
622 ( Bilstein (Briloner Heights)) |
18th | 220.1 |
214.1 |
267.9 | 814.5 |
The following table lists smaller tributaries of the Rhine with an average water flow of less than 20 m³ / s.
| Rhine km | R / L | Tributary | mean discharge in m³ / s | Length in km | Catchment area in km² |
|---|---|---|---|---|---|
| 703.3 | R. | Wupper | 17th | 117 | 827 |
| 735.5 | L. | Erft | 16 | 103 | 1838 |
| 797.7 | R. | Emscher | 16 | 84 | 775 |
Past floods
The Lower Rhine region has often been over the centuries of severe floods struck. For example, in 1809, 1855 and 1861 the Banndeich broke under the pressure of ice masses (" ice drift "). In 1926 the Dutch Duffel (is the Ooijpolder meant?) Ran from Nijmegen to the cross dam. The same flood in 1926 flooded about 40 percent of the Prussian Rhine Province (40% of 26,995 km² is about 10,800 km²).
In February 1945 units of the Wehrmacht blew up dikes on the German-Dutch border to prevent the advance of the Western Allies ; it became clear what enormous and widespread impact it can have when dikes break in a flat area.
In 1988, at the end of 1993 and 1995 - i.e. within seven years - there were three “100-year floods” (= floods of the century ; list of other Rhine floods here ).
The map on the right shows how many German regional authorities are involved between Bonn and the border with the Netherlands.
- Kleve district (left + right)
- District Wesel (left + right)
- Duisburg (left + right)
- Krefeld (left)
- Rhine district Neuss (left), Düsseldorf (right), district Mettmann (right)
- Cologne (left and right), Leverkusen (right)
- Rhein-Erft district (left)
- Rhein-Sieg district (left and right)
- Bonn (left and right)
In Germany, 12 districts or urban districts are concerned with 'flood protection on the Lower Rhine'; they belong partly to the Cologne district and partly to the Düsseldorf district . The state of North Rhine-Westphalia is also involved. Among other things, it works in the International Commission for the Protection of the Rhine and in the German-Dutch working group on floods.
History of flood protection
On May 15, 1990 (two days after the NRW state elections , in which Prime Minister Johannes Rau defended his absolute majority and 26 months after the first flood), the responsible department of the Düsseldorf district government criticized the organization of flood protection on the Lower Rhine in a situation report :
“The construction, maintenance and defense of the Rhine dykes have so far been organized heterogeneously, be it by municipalities, dyke associations with tangible membership or dyke associations with corporate membership. In the metropolitan area between the border with the Cologne district government and the northern city limits of Duisburg, municipalities and associations with municipal membership without costs for the beneficiary citizens dominate, downstream associations with in rem membership with cost allocation, but also without reserves. Approx. 150 km of Rhine dykes are in need of rehabilitation. The state finances dyke construction and renovation with up to 80%, according to a report from 1990 management report by the state government, some "affected" agreed that the flood protection on the entire Lower Rhine, under the aspect of damage prevention and precaution, will be reorganized must. "
In 1996 the state of North Rhine-Westphalia adopted a flood protection concept. Two dike relocations were included in this concept: Lohrwardt (13 million m³ on 275 hectares) and Mündelheim (5 million m³ on 100 hectares = 1 km²).
In November 1997, the province of Gelderland (Netherlands), Rijkswaterstaat (Dutch authority for water management ) and the NRW Ministry for the Environment, Spatial Planning and Agriculture (former Minister: Klaus Matthiesen ) signed a 'Joint Declaration for Cooperation in Sustainable Flood Protection' and (to coordinate studies and developments to improve flood protection) a German-Dutch working group “Flood Protection” set up.
In September 2010 a congress on flood protection in North Rhine-Westphalia - status and perspectives took place. While in 1995 275 km (= 83%) of the 330 km Rhine dykes were to be rehabilitated and 38 km were still to be examined, (as of May 2010) 193 km were completed or under construction (193 of 275 = 70%), 72 km were still closed renovate. Since 1995, 594 million euros have been spent.
Some severe floods (for example the Elbe floods in 2002 , 2006 , 2010 , 2011 and the floods in Central Europe in 2013 ) - each with damage amounting to billions - have increased awareness in recent years of the importance of flood protection. For example, during the floods in June 2013, an unrenovated dike near Arnsnesta / Herzberg (Elbe-Elster) on the Black Elster ; as a result, a very large area was flooded. After this flood, the federal government started a "National Flood Protection Program" in cooperation with the federal states (they are responsible for flood protection). The federal states should coordinate their measures on a supraregional level and in relation to the river basins. Flood risk management plans are to be drawn up (as of 2013) by the end of 2015.
The Elbe is a lowland river for hundreds of kilometers (approximately from Torgau downstream) , ie it has little gradient or flows through a flat area - similar to the Lower Rhine. The problems of their flood protection are therefore similar.
Current flood protection concept of the state of North Rhine-Westphalia until 2015
The current "flood protection concept of the state until 2015" comes from the summer of 2006 , i.e. from the time of the black and yellow state government ( Rüttgers cabinet ). Jürgen Büssow (SPD), President of the District of Düsseldorf from 1995 to 2010, presented the concept at that time. According to this, 115.5 km of dykes still had to be renovated (forecast at the time: 299.3 million euros in construction costs, 240 million of which were funded by the federal government) and 44.5 km of dykes had not yet been investigated.
Hazard potential
Large areas of the Rhenish Bay ("left Lower Rhine") could "fill up" in the event of a severe Rhine flood:
- between Cologne and Duisburg, the degree of flood protection is inconsistent and too low, especially in Düsseldorf / Neuss, Krefeld and Rheinhausen
- from around 12,000 m³ / s - well below the applicable design flood, large areas are threatened with irreparable waterlogging and uninhabitable
- In the mining area around Kamp-Lintfort, large areas have sunk by up to 20 m after the coal was extracted; there, a flood over the dike would put land areas particularly deep under water - so deep that houses would be completely flooded and residents would not be able to take refuge on roofs and be rescued there by helicopter.
There are also some large companies in the chemical industry near the Rhine . Mention may be three works of Bayer AG ( Leverkusen (It is one half in Leverkusen- Wiesdorf and the other in the Cologne district Flittard ), Dormagen and the plant in plant in Krefeld - Uerdingen ) - Since 2008, the three collectively " CHEMPARK " called.
In December 2005 the Ministry for Climate Protection, Environment, Agriculture, Nature and Consumer Protection of the State of North Rhine-Westphalia (MUNLV NRW) wrote about the situation further upstream:
"The situation is different with outflows between 13,000 m³ / s and 15,500 m³ / s (BHQ) above Krefeld. On the southern Lower Rhine, there would be floods first in the greater Cologne / Bonn area to around Düsseldorf / Dormagen, and with increasing height of the flood peaks also in the central part to about the confluence of the Ruhr. [Note: the Ruhr flows into the Rhine near Duisburg- Ruhrort ] In order to prevent flooding in this area, protective systems of around 200 km in length would have to be increased by an average of at least 1 m. Such technical measures are out of the question in the southern Lower Rhine region, for financial as well as ecological and social reasons. You would e.g. B. not accepted in Bonn and Cologne and exceed the limits of what is technically feasible because of the building close to the river. Therefore, the results of the study will not lead to general increases in protective systems and dykes. "
Whether the ministry today - after the Elbe floods in March 2006 , Elbe floods in 2009 , floods in 2009 on the Danube, Moldau and Oder , floods in Central Europe in spring 2010 , floods in Central Europe in 2013 and other severe floods - would still come to these conclusions or theses appears to be questionable .
The 'Flood Protection Concept of the State by 2015' presented in 2006 includes:
“One hundred percent flood protection cannot be achieved. So there remains a residual risk that the actually protected areas will be flooded. The damage is then usually greater than without protective systems. For this reason, considerations about how to deal with the residual risk have come to the fore in recent years, primarily in areas that have been changed by mining influences. The aim is to replace the previous strategy of hazard prevention with a new strategy of risk management. Several scenarios were considered in individual studies. This includes in particular the risk assessment procedure for dykes, which was developed by RWTH Aachen University. Within the procedure, the risk is defined as the product of the failure probability of the protection system and the potential damage. The goal is to keep the risk as small as possible. This can be done by increasing the demands on the structures, but also by good disaster management. The risk assessment process is objective, transparent and specific. It is suitable for determining the risk of hydraulic structures and defining concrete measures to reduce the residual risk. "
Fundamental problem: upstream / downstream
There is an economic interest in investing funds for flood protection (e.g. building dykes) as efficiently as possible (= achieving the highest possible benefit per euro invested).
Upstream and downstream residents have particular interests ; some of these are incompatible with one another. Higher levels (state, state commissions or federal government) can make efficient decisions.
As a rule, those lying below benefit from flood protection activities (e.g. investments) by those living above .
In law this is discussed as the "upstream-downstream problem".
Dike relocation as a panacea?
In some letters to the editor and press reports, the idea was suggested that you only need to move a few dykes back and that there is already plenty of room for flooding or that its apex will be significantly lowered. In fact, that would only be the case if the Rhine had many millions of cubic meters more space.
Three well-known institutions -
- Rijksinstituut voor Integraal Zoetwaterbeheer en Afvalwaterbehandeling (RIZA; 2007 it was included in the 'waterdienst' of the Rijkswaterstaat ; since April 1, 2013 it has been called 'RWS Water, Verkeer en Leefomgeving')
- the State Environment Agency NRW (LUA NRW) and
- the Federal Institute for Hydrology (BfG) -
and researchers from the province of Gelderland developed the study Transboundary Effects of Extreme Floods on the Lower Rhine between 2002 and 2004 .
The summary of this study contains a section that is fully cited below:
Study (2004) on the effects of flood-reducing measures
The effect of retention polders on peak runoff is heavily dependent on the peak height and the shape of the hydrograph of the flood under consideration. Therefore, the protection goal for their use must be precisely defined and implemented through structural measures, e.g. design of the inlet and outlet structures or control.
Relocating dykes has an effect mainly locally and towards the upstream. When the cross-section is enlarged, the water level drops with hardly any changes in the runoff. Immediately below, there may be a slight increase in the water level if the transition to the existing dike line leads to a significant narrowing of the profile. This should be taken into account when creating such measures.
In the current planning, the system of flood-reducing measures on the Lower Rhine shows its best effects on events of the magnitude of the 1995 flood. Targeted use of the measures, especially the retention polders, can increase their peak-reducing effect on floods in the area of the design runoff.
In the current state of planning, the flood-lowering effect of the measures in NRW on hydrographs with peaks in the area of the design flood in the Bislich area, approx. 40 km above the border, 15 to 20 cm or 1 cm at the border itself.
By optimizing the control of the design flood, the flood-lowering effect can be improved, so that, for example, in the Bislich area, water level reductions of up to 25 to 30 cm or at the limit up to 6 cm can be achieved.
The flood-reducing measures in the Netherlands are intended to ensure that 16,000 m³ / s can be safely discharged in the future instead of 15,000 m³ / s instead of the current dyke elevation. The resulting drop in the water level of around 30 cm at the border has a decreasing effect up to around 50 km upstream.
By combining the effects of the planned measures in the Netherlands and the measures in North Rhine-Westphalia, according to the current planning status for extreme floods that go beyond the design flood, water level drops of up to 30 cm at the border and up to 25 cm in the Bislich / Lohrwardt area can be achieved become. If the currently planned measures in North Rhine-Westphalia and some additional measures, e.g. to remove obstacles to runoff, are coordinated with the design flood discharge, water level drops of up to 40 cm at the border and in the Bislich / Lohrwardt area can be achieved in combination with the measures in the Netherlands . In other places the reduction in the water level is less.
This makes it clear that the measures in North Rhine-Westphalia and the Netherlands complement each other. In this way, for example, an early overflow of the flood wall in Emmerich can be counteracted. Overflowing the flood wall at Emmerich would also affect Dutch territory.
This fact shows the mutual benefit of cross-border efforts in flood protection and the necessity of cross-border coordination of flood-relevant planning and measures.
See also
- Water and soil association - a dike association is one such
- Geology of the Lower Rhine Bay
- Directive 2000/60 / EC (Water Framework Directive)
Web links
-
Environment Ministry NRW :
- (Ed., May 2011): Living with water - flood protection in NRW. (pdf, 1.8 MB)
-
Flood hazard maps and flood risk maps
- Sub-catchment area: Rheingraben-Nord (click on the overview map leads to detailed maps)
-
Website for the implementation of the European Water Framework Directive (WFD) in the sub-catchment area Rheingraben-Nord
- http://www.hkv.nl/upload/publication/Hydraulische_studie_zur_abfluss-und_strukturverbesserung_am_Rhein_in_NRW_HJB.pdf (pdf, 30 pages, December 2010?; 2.2 MB)
- International Commission for the Protection of the Rhine : Floods
- Federal Institute for Hydrology :
Individual evidence
- ↑ Report on the preliminary assessment according to the EC Flood Risk Management Directive (EG-HWRM-RL) in NRW June 2011 ( Memento of the original from March 24, 2016 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. PDF for flood risk assessment
- ↑ Archived copy ( memento of the original dated June 6, 2013 in the Internet Archive ) 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. P. 2 of 78 (PDF; 9.0 MB)
- ↑ hochwasserplattform.de pages 33–44
- ↑ the Cabinet Rau III followed the Cabinet Rau IV
- ↑ PDF, 2 pages
- ↑ This can be seen on page 6 (PDF; 690 kB)
- ↑ Annual Report 2003, p. 1. ( Page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. (PDF; 135 kB)
- ↑ pdf, 31 pages ( Memento of the original from March 4, 2016 in the Internet Archive ) 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.
- ↑ Anita Tack, Minister for the Environment, Health and Consumer Protection on August 16, 2013 ( Memento from November 5, 2014 in the Internet Archive ) in front of the Mecklenburg-Western Pomerania state parliament
- ↑ PDF, 13 pages
- ↑ OFFICIAL SHEET G 1292 for the Düsseldorf administrative region (June 24, 2004; PDF; 26 kB)
- ↑ Key sentences from ... (PDF; 45 kB) Cross-border effects of extreme floods on the Lower Rhine (2004, 160 p.) Bibliograph. Data
- ↑ Az: IV-10-4290 of December 22, 2005, p. 4, quoted from Feldmann
- ↑ Page 11 of the pdf, numbered as "Page 10"
- ^ Upstream-downstream problems. The relationship between upstream and downstream in preventive flood protection measures on (international) rivers (PDF; 227 kB) RA Johannes Bohl, lecture (2011), p. 3f.
- ↑ for example: RWS water, traffic and living environment . www.rwsleefomgeving.nl
- ↑ Cross-border effects of extreme floods on the Lower Rhine. Final report. Düsseldorf 2004, ISBN 90-369-5638-2 .
