Descriptions of demonstration projects
The demonstration project centres on the areas around the confluence of the Rivers Ihme and Leine. The project will address the requirements of the Floods Directive to carry out flood hazard and risk assessments and develop flood risk management plans for river and surface water flooding taking account of climate change and planning proposals.
The demonstration project will comprise the following elements:
Data base improvement
A high resolution digital elevation model is required to enable accurate determination of flood depth in at risk areas.
The following actions are required:
- The acquirement of a high resolution DEM using airborne Lidar surveys
- Improvements to the new DEM to take account of local circumstances not visible from the air
Modelling of flood probability
Upgrading existing modelling techniques to include the use of the high resolution DEM to predict surface pathways and flood depths for river and surface water flooding
The following actions are required:
- Modelling for a range of scenarios between the areas of Kolding and Herrenhausen
- Creation of flood extent maps for different event probabilities
- Creation of flood depth maps for critical transport routed and other critical infrastructure
- Assessment of Flood risk Management options in the urban area
- Utilizing the model for raising the awareness of the different user groups, (the public, planners and fire service) by means of a front end application in the intranet of the LHH / region and on the Internet
Flood Risk Assessment
For the selected pilot area of the flood extents and depths for different flood events up to the 1 in 100 year probability are calculated. Next the consequences of the flooding will be assessed and will be combined with the probability to identify the flood risk for a range of event probabilities.
Following the assessment of flood risk and the production of detailed flood hazard and risk maps options for flood risk reduction measures will be assessed using cost benefit approaches and a Flood Risk Management Plan will be developed.
Assessment of future landscapes
The needs and aspirations of stakeholders in the current and future urban landscape will be identified through the urban planning process. The process will:
- Identify and engage with stakeholders who are relevant to the study
- Consult with stakeholders to identify individual goals
- Work with stakeholders to achieve a consensus for future land and water management targets
Optioneering of measures
Using the consensus for future land and water management targets options for structural flood defences will be considered. The costs and benefits of each option will be compared and the performance will be evaluated against the defined target to identify the non structural responses required to manage the residual risk.
Communication
The results of the optioneering process will be communicated to a wide range of stakeholders. It is proposed to develop communication processes appropriate to the different target groups to demonstrate the scope, cost and benefits of the different options and make them aware of the residual risk.
Implementation
The final step in the process will be the selection of the preferred option and the development of a programme for implementation of the structural and non-structural measures in the form of a Flood Risk Management Plan.
Legacy
As well as developing the Flood Risk Management Plan, the demonstration project will leave a legacy networks and a centre for excellence for flood risk and water management in the Hannover Region.
