KliBiW – Global climate change – water-management impact assessment for the inland – stage 4 für das Binnenland – Phase 4
Background and Goals
The global warming gives reason to expect impact on the water resources in Lower Saxony. Among the possible effects are the limitation of available water supply and the increase of flood events. For this reason, the project KliBiW (Global climate change – water-management impact assessment for the inland) was initiated in 2008. The aim was, to quantify the impact of climate change on water management in Lower Saxony more detailed, taking into account the local circumstances. The fourth stage of the KliBiW project had the aim to evaluate the water-management effects of climate change for all risk waters in line with the EU Floods Directive (Directive 2007/60/EC) in Lower Saxony. The analyses are based on current climate projections provided by international climate research. Recommendations for action shall be developed on the basis of the project’s results. Furthermore, the state’s service of hydrology (GLD – Gewässerkundlicher Landesdienst) is supposed to be enabled to describe the impact of climate change statewide according to the statutory requirements, to develop prevention measures, and to advise decision makers. As part of climate adaptation, another goal was to provide a basis of decision-making for the possible definition of climate coefficients.
Content time
Research area/region
Country
- Germany
Region of implementation (all German federal states)
- Lower Saxony
Natural spatial classification
- North-West German lowland
Steps in the process of adaptation to climate change
Step 1: Understand and describe climate change
Approach and results
During the analysis period from 1951 to 2015, data for selected climate parameters of 175 precipitation stations and 20 climatic stations were analyzed for the project phase. For the observed climatic conditions a regionalization took place. For this purpose, different interpolation methods were compared and subsequently the most suitable method was selected. In addition, trends in outflow ratios for selected parameters were analyzed and regionalized.
For climate modeling, 14 climate model chains were used. The climate projections selected for the project are based on the emission scenarios SRES A1B and RCP8.5.
Parameter (climate signals)
- River flooding
- Altered rainfall patterns
- Higher average temperatures
- Extreme precipitation (incl. hail, snow)
- Dry periods
Further times
1950-2015
Step 2a: Identify and assess risks - climate effects and impact
Approach and results
The results for the two observed climate scenarios lead to the conclusion that the peak discharges of flood events in Lower Saxony will increase strikingly in the far future. These climate effects will influence various areas of the water-management planning, for example:
- Designation of flood risk areas
- Design of flood protection systems
- Control of storage tanks
- Technical flood protection measures with flexible design options
- Flood risk management
- Flood prevention
- Flood forecast (short warning time in case of increased summer floods)
- Flood retention area development
- General drainage planning
It is pointed out that the climate changes in Lower Saxony will also affect other (water-management) fields of action. These include the low water management, the groundwater conditions and the water quality.
Step 3: Develop and compare measures
Measures and/or strategies
On the basis of the project results, the development or introduction of climatic values, either as fixed values or as value ranges, is recommended for planning and design issues. To begin with, a Lower Saxony wide climatic coefficient of 1.15 is recommended. This value is based on the averaged change signals of both climate model ensembles (SRES-A1B and RCP 8.5) for the far future (2071-2100). A steady revision and updating of the climatic values using future development methods and findings is recommended. It is recommended to apply climatic parameters – especially in the case of expensive measures – with due care because of the still existing model uncertainties. The procedure of the “no regret” recommended in the southern German states should also be taken into account in Lower Saxony.
Time horizon
- Presence
- 2021–2050 (near future)
- 2071–2100 (far future)
Participants
Funding / Financing
Lower Saxony Ministry for Environment, Energy and Climate Protection
Project management
Lower Saxony Water Management, Coastal Defense and Nature Conservation Agency (NLWKN)
Cooperation/Partners
Institute for Hydrology and Water Management of the Leibniz University Hannover (WAWI LUH)
Leichtweiß Institute for Hydraulic Engineering of the Technical University Braunschweig (LWI TUBS)
