EroL - erosion events due to heavy rainfall in the Markgräflerland

Background and Goals

In the last decade, an increase in erosion events associated with heavy rainfall has been observed in the district of Lörrach. Above all, the so-called Vorbergzone of the Black Forest is in terms of their topographical and geological conditions in connection with land use potentially at risk. The aim of the project is to protect the population from erosion damage caused by heavy rain. For this purpose, hazard analysis and erosion hazard maps will be prepared in the affected municipalities. After the risk analysis has been completed, an action plan will be developed together with the district, which will contain information on area provisioning, crisis management and the conception of measures. This concept of action is presented in the municipalities, a network is set up and support given for the implementation.
With the help of the heavy rain and erosion hazard maps, the district has a tool to better fulfill its precautionary obligation to citizens and municipalities. This way, damage can be more effectively avoided or minimized.

Content time

since

Research area/region

Country
  • Germany
Region of implementation (all German federal states)
  • Baden-Württemberg
Natural spatial classification
  • Upper Rhine Rift
Spatial resolution 

District of Lörrach

Steps in the process of adaptation to climate change

Step 2a: Identify and assess risks - climate effects and impact

Approach and results 

Based on flow path maps, maps are prepared for erosion hazard. Realistic present and future scenarios are included. The erosion maps are generated using the LISEM (Limburg Soil and Erosion Model) erosion and runoff model. The heavy precipitation from the KOSTRA heavy rain maps illustrates the current erosion risk. The heavy rain hazard maps are an important tool for the subsequent risk management process and for the creation of alarm and operational plans.
In principle, three scenarios are presented (according to "Guidelines on Municipal Heavy Rain Risk Management in Baden-Württemberg", LUBW, 2016):
Rare discharge events: Statistical precipitation event of 1 hour, which occurs approximately every 10 - 50 years
Extraordinary discharge events: Statistical precipitation event of 1 hour, which occurs approximately every 50 - 200 years
Extreme runoff events: Extreme precipitation event with an occurrence probability greater than 200 years, where large-scale flooding occurs
In the map display, a distinction is made between flood expansion maps and flood depth maps.

Step 2b: Identify and assess risks - Vulnerability, risks and chances

Approach and results 

As part of the risk analysis, a comprehensive risk assessment is carried out, which determines critical areas and creates risk maps. During site inspections of the areas particularly affected, hazard areas are identified and from this risk profiles are derived. The localization of problem areas should take place in seminars or workshops with all involved actors, in which first solutions are discussed.

Step 4: Plan and implement measures

Measures and/or strategies 

The possible measures for the protection against erosion events are put together via the fields of action agriculture, forestry, nature conservation, water balance and roads (agricultural adjustment in agriculture, municipal construction measures etc.). The action plan is drawn up in consultation with the established network of municipal specialist offices, agriculture, forestry, affected citizens, specialist planners as well as rescue and emergency response teams. Subsequently, a network will be set up, which will be involved in the implementation of measures. The integration and synergy potentials are e.g. probed with landscape plans or ecological account regulations.

Costs of the measures 

On the part of the district is informed about financial start-up and implementation options and supported technically in the implementation.

Step 5: Watch and evaluate adaptation (monitoring and evaluation)

Approach, objective and results of the monitoring and/or evaluation 

After the project has ended, it should be ensured that measures are implemented and that the topic remains with the persons affected.

Participants

Funding / Financing 

Federal Ministry for the Environment, Nature Conservation and Nuclear Safety

Project management 

District Office Lörrach

Cooperation/Partners 

geomer
Terra fusca Engineers Partnership Company
BGU Consult

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Fields of action:
 civil protection and disaster management  soil  cross sectoral