Subject of the question:
At the beginning of the year, parts of the district, for example in Nidderau, were flooded. More than 180 people were killed in the flood disaster in July in Rhineland-Palatinate and North Rhine-Westphalia. It can be assumed that the extreme weather conditions will continue to increase. Therefore, it is important that there is a functioning flood protection in the district.
Questions:
1.Is it planned to review the specified or undefined flood zones or to expand the specified areas due to the recent flood events in order to prevent areas not specified in major flood events from being particularly affected due to insufficient protective measures (e.g. in the case of an HQ100 or in the case of extreme floods by enormous amounts of rain in a short period of time exceeding HQ100)?
Answer: The floodplains are subject to a continuous review by the competent Upper Water Authority at the government offices. As part of flood risk management, hazard and risk maps, which also map extreme floods, are drawn up.
2. How far are the plans for salt and brittle retention basins?
HRB Bad Soden/Salt
In accordance with the resolution of the Association Meeting of 2 May 2013, the flood retention basin in Bad Soden/Salz has the highest priority.
As part of a citizens' assembly in Bad Soden-Salmünster on 7 March 2017, the Hessian Ministry for the Environment, Climate Protection, Agriculture and Consumer Protection (HMUKLV) agreed to a separate measuring program to prove the stability of the centuries-old landslide, as the approval and specialist authorities of the country have questioned whether it can be approved since the preliminary planning was completed in 2013. The Association Assembly decided on 29 March 2017 to make the financial resources available. In accordance with the decision of the association bodies, the planning services were continued. The service phases 3 and 4 (design and approval planning) were commissioned subject to planning approval. The specifications for structural design and technical equipment have been developed since then. The environmental planning services have started as planned and the mapping scope has been coordinated with the RPU. A scoping document has been submitted to the Regierungspräsidium Abteilung IV – Arbeitsschutz und Umwelt Frankfurt (RPU) for examination.
The deadline for dealing with the problem of landslide, which is essential for further planning and for environmental planning in particular, was set by the Wasserverband Kinzig (WVK) and the engineering office commissioned with the investigations carried out above, and took place on 4 April 2019 with the approval authority (RP Darmstadt) and the state technical authority (HLNUG). Measurements and evaluations will continue until the end of 2021. A positive decision by the RP and the HLNUG is still pending.
Examination scope and course:
In consultation with the competent authorities, drilling was carried out for three inclinometer measurements and three groundwater measuring points. In addition, a geodetic monitoring program consisting of 30 measuring points is included.
The inclinometer measurements are to be measured quarterly, the groundwater measuring points monthly and the geodetic measuring points biannually. The scope of the project also includes laboratory tests and the summary of all results in a report.
Previous survey work and drilling were completed between February and August 2018. On the recommendation of the HLNUG, an additional borehole for a groundwater measuring point had to be drilled in addition to the drilling planned in advance.
The evaluation of the measurement results shows that a slope movement has not been discernible since the beginning of the measurements. The planned investigations continued in 2020 and confirmed the results identified so far. Slope movements are not detectable from the point of view of the project controller.
The HLNUG interpreted the movements as creep deformations and further proposed a shortening of the measurement interval of the groundwater and inclinometer measurements after heavy and continuous precipitation (also snow melt) by data loggers, as well as the recording of the precipitation data directly in the investigation area (e.g. by means of weather station).
As a result, the specialist office was therefore advised to plan possible technical security measures on the basis of the information already available as well as stability calculations and to install them with commissioning of the basin. A warning and alarm plan should also be drawn up containing these slope protection measures as ‘Plan B’. The necessary definition of criteria for the stability calculation was carried out in coordination with the HLNUG in the first quarter of 2020. The calculation results were submitted in October 2020. In the course of 2020, the different viewpoints on the part of the HLNUG were communicated again. In contrast to the geologists and geotechnicians of the specialist office, the responsible processor in the HLNUG still sees a risk of slippage of the slope. In the fourth quarter of 2020, an appointment was planned with the HLNUG to discuss the concerns of the HLNUG final and to bring about a technical and economic solution. This date did not take place due to the pandemic.
After the flood in January 2021, a complementary measurement and assessment was carried out. Based on this, the latest status report of 19 March 2021 identified very slow creep deformations that may have been caused by the flooding. From the expert's point of view, an active slip movement is still not recognisable. A realisation of the HRB would be possible with the construction of a relief drainage of the slope by means of drainage trenches in conjunction with further observation.
According to an initial assessment, the costs for the slope protection measures (Plan B) amount to between €1.2 million and €4.8 million gross, depending on the protection variant. Alternatively, an HLNUG map is available for further locations on the salt.
The Kinzig Water Association is aiming for a final consultation on this at the latest for the fourth quarter of 2021. This should be used in the perspective of a final decision on the general follow-up of the project.
The further planning of the commissioned offices was therefore initially interrupted by mutual agreement. This does not incur any additional costs for the Kinzig Water Association. After a final decision by the RP technical supervisor, these can be resumed.
HRB Weilers/Bracht
According to a resolution of the association meeting of 2 May 2013, the Weilers/Bracht flood retention basin has the second highest priority after the Bad Soden/Salz flood retention basin.
The implementation of the planning services for this flood retention basin started in August 2015. In the four construction meetings after the start of the project and an official appointment, the planning progress was presented and explained. In September 2016, the final report on the planning results of the preliminary planning was handed over to the Regierungspräsidium Division IV - Occupational Safety and Environment Frankfurt (RPU). According to the Authority, the examination of the results of the investigation should be completed in December 2016. On 22 March 2017, the RPU sent the comments to the WVK by e-mail. Reasons for exclusion that make it impossible to continue planning have not been identified.
As a result of the meeting on 8 September 2017 at the RPU, it was further stated that also with regard to Groundwater / water protection area / drinking water extraction there are no grounds for exclusion at the site.
In December 2018, further project management services were commissioned following a legally compliant call for tenders. The call for tenders for engineering services was divided into Lots 1 ‘Property planning’, 2 ‘Structural planning’, 3 ‘Technical equipment’ and 4 ‘Environmental planning services’ and based on this, contracted in December 2019. The one for the 8th. The planned scoping date at Bürgerhaus Wächtersbach in December 2020 had to be cancelled due to the restrictions resulting from the Covid-19 pandemic.
A two-stage written procedure was then carried out by the RPU Frankfurt. After the documents had been sent by the RPU to the authorities, the first stage was completed with a deadline of 4. December 2020 the possibility to formulate questions from the authorities on the scoping document. Following their reply by the WVK, the written comments were received, evaluated by the project controllers and their consideration for the further planning was agreed with the contractors.
The still unresolved questions on the scope and delimitation of the specialist article Water Framework Directive, effects and compensation measures regarding the drinking water protection area Neuenschmidten Süd as well as on the control concept for the HRB - in particular function and handling of the existing level Bracht - must be coordinated with the Darmstadt FP in October 2021.
The further technical planning runs on time and is within the assumed cost framework. It is foreseen to submit the approval documents in full by the end of 2021, so that the approval process can start in 2022.
a. When is completion expected?
HRB Bad Soden/Salt: Completion can only take place after a positive decision by the RP on the landslide. Therefore, a date is not derivable from today's point of view.
HRB Weilers/Bracht: Plan approval request is foreseen for November 2021. From today's point of view, construction will take place between 2024 and 2026.
b. What work still needs to be completed before completion?
HRB Bad Soden/Salt: Approval must be ensured with a positive decision of the authority on the subject of landslide. Decision to be taken in the fourth quarter of 2021.
HRB Weilers/Bracht: Plan approval application submitted by the end of November 2021 and thereafter according to the further planning steps until implementation.
c. When does the circle expect completion?
See reply to (a) and (b)
3. The flood disaster in Ahrweiler pushed the existing flood warning and reporting systems to their limits. Is it planned to expand, modernise and/or increase the possible levels to be indicated?
The responsibility here lies with the Hessian State Office for Nature Conservation, Environment and Geology.
4. What is the reporting chain for special flood events in the Main-Kinzig-Kreis?
For the Main, the Nidder and the Kinzig (with tributaries) there are Central Flood Service Regulations. The Upper Water Authority of the Regierungspräsidium Darmstadt, Dept. of Occupational Safety and Environment Frankfurt, assesses the danger situation on the basis of the weather forecast of the German Weather Service, level reports and notifications from precipitation recording stations. For Main and Nidder, the Department of Water and Soil Protection of the Office 70 – such as the municipalities, railways, road authorities, security centre, district press office – is an end recipient. In the case of the Kinzig, the transfer is usually carried out by the Department of Water and Soil Protection of the Office 70 by fax or by telephone outside the usual hours of service. In the upper reaches of the Kinzig (above the dam wall), the department independently provides information to affected recipients when certain amounts of precipitation have been reached. In addition, flood warnings are available on the Internet.
5. Has the district decided on further flood protection measures after the flood disaster in Ahrweiler?
a. If so, what measures have been adopted?
No. If the supervisory authority sees a need for adaptation, plans can be adapted accordingly by the water association and/or the municipalities.
6. In the Main-Kinzig district there are protective structures in Biebergemünd, Bruchköbel, Gelnhausen and Hanau.
a. In extreme floods, do these sufficiently protect against enormous amounts of rain in a short period of time that go beyond HQ100?
i. If not, are these protective structures planned to be extended?
Municipal flood protection is the responsibility of cities and municipalities. A review of current planning, for example in the context of certain statistical events such as an HQ extreme, is discussed with the supervisory authority. If the supervisory authority sees a need for adaptation, plans can be adapted accordingly by the water association and/or the municipalities.
7. Since 2006, the Kinzig Water Association has been implementing the state pilot project ‘Water-related flood protection in Kinzig’.
a. What measures have been implemented since then?
In addition to the plans for the Bad Soden/Salz and Weilers/Bracht flood retention basins, the Kinzig Water Association is also advancing the plans for the Erlensee/Fallbach flood retention basin. The feasibility study with geotechnical exploration for the preferred location is expected to be available at the end of October 2021.
b. What measures are currently being implemented or are to be implemented in the future?
HRB Bad Soden/Salt: The opening of the planning approval procedure is possible at short notice if the supervisory authority agrees to the continuation of the planned slope protection measures.
HRB Weilers/Bracht: The planning approval request is scheduled for November 2021.
HRB Erlensee/Fallbach: The feasibility study with geotechnical exploration for the preferred location is available around the end of October 2021.
8. For a protection fee, municipalities can submit an application to the Hessian State Office for Nature Conservation, Environment and Geology for the preparation of flow path maps. Hydrological risk analyses are carried out in climate municipalities with 100 %, for other municipalities with 80 % promoted.
a. Is it planned that the district will support the municipalities in financing, for example by taking over the protective fee or the ineligible residual costs?
b. How many municipalities in the MKK have already submitted an application for flow path maps or hydrological risk analyses?
The task of municipal flood protection is the responsibility of the municipalities.
To a.) So far, no municipality with the desire for support has come to the Main-Kinzig-Kreis.
No information is available to the Main-Kinzig-Kreis on this question.
9. In order to prevent the effects of heavy rain events, it is important to keep the precipitation in the area
a. What measures are being taken by the Main-Kinzig district to prevent erosion events, especially on the agricultural land in the district area, or to improve soil functions?
Since 2012, the Main-Kinzig-Kreis has been successfully implementing an agricultural consulting project for the protection of waters within the meaning of the Water Framework Directive and for soil protection with the support of an engineering office. The funding for this is provided by the state of Hesse on the basis of contracts with the district, which are decided by the district committee. Part of this project is, among other things, an erosion consultation at individual farm level for areas with high priority as well as at group and inter-farm level to raise awareness in the context of agricultural management. As exemplary erosion protection measures, which are advised and also implemented by the companies, are to be mentioned: Evaluation of the current management of the farms with optimization proposals, soil studies, identification of the need for action, processing across the slope, establishment of catch crops also as a basis for a mulch seed with reduced tillage, installation of erosion protection strips, participation in erosion-related support measures, thematic field visits, workshops.
Erosion protection also means soil protection. The exemplary measures will preserve the soil functions and ultimately improve them. The advice on a well-thought-out crop rotation design including catch crops or underseeds, plowless tillage and direct sowing methods, plant-recoverable fertilisation and minimized plant protection have a positive effect on soil functions.
In addition, the Office for the Environment, Nature Conservation and Rural Areas and its specialist departments represent, among other things, the interests of soil protection in the numerous planning and approval procedures.
Precautionary soil protection outside of measures for which the MKK is responsible (e.g. construction application procedure) is the responsibility of the Upper Soil Protection Authority at the Regierungspräsidium Darmstadt, Dept. of Occupational Safety and Environment Frankfurt.
b. on which waters in the district are restoration measures planned or have been implemented in the last 10 years in order to create targeted floodplains?
Virtually every water structure improvement in the sense of establishing a near-natural state serves at least indirectly to protect against flooding, for example by extending the flow times. In the Main-Kinzig district, 41 restoration measures, 14 measures under the Water Framework Directive (e.g. removing transverse structures) and 6 flood retention basins have been approved in the last ten years. Retention basins in construction areas or on roads are not included, which are not intended to buffer flood events, but heavy rain events. The measures are spread over the district from the Braubach in the west to the Kinzigoberlauf in the east.
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