Tor Haakon Bakken, Bendik Torp Hansen and Lennart Schönfelder
Hydropower reservoirs provide important flood dampening services to society, preventing massive economic damages and potential loss of life every year. Knowledge about and appreciation of this service is becoming increasingly important in light of a climate shifting towards more extreme precipitation events and a globally diminishing reservoir storage capacity due to sedimentation. Norway is no exception to the value of flood dampening from reservoirs, and hydropower operators are expected to manage their reservoirs to prevent floods. Despite the legal responsibility imposed on operators, there is no reimbursement for lost production due to heavy reservoir drawdown. There is also no reward (beyond reputation) for preventing damages. Increased knowledge and awareness about the economic value of flood dampening could help create a system where the service is properly rewarded and where risks concerning drawdown are justified by reimbursing potential losses. Additionally, it would be useful for reservoir operators to have more detailed knowledge about the economic damage from floods to ensure an optimal balance between production and flood dampening.
A conceptual methodology for determining the economic value of flood dampening has been developed in the research center HydroCen. In very brief terms, it consists of using hydraulic models to determine water-covered areas for a number of different flood discharges, extracting the areas of building and land-use types affected by the flood, calculating the total damages based on the cost per unit area of each type of building and land use, and lastly creating a curve of discharge versus flood cost for the location of interest. The primary task that remains is to determine what the actual cost per unit area of each type of building and land use is.
The Master's thesis consists of the following main tasks:
- Consulting literature and contacting industry partners such as insurance companies and government agencies to determine the approximate cost per flooded unit area for each building and land use type
- Using an existing (or setting up a new, if necessary and possible) calibrated hydraulic model to calculate flooded areas for a range of discharges for a test case study with historically damaging floods
- Calculate flood cost for the different discharges based on flooded area of each type and creating discharge-cost relationships
- Comparing known flood costs to the costs given by the methodology for the test case study to assess performance