Detailed data of buildings in the city centre has been collected during the project. Together with a web-based visualization of vulnerable buildings and regions the assessment of the risk and a proposition of possible adaptation measures is possible.
Potential urban flooding risk hot-spots were identified in the city centre. Those include the area of the hospital, several University buildings and the historic centre of Innsbruck. Hence a detail study area was delineated, which encloses the above mentioned hot-spots
Those hot-spots were chosen as there is either a high vulnerability level (hospital) or a high hazard level (historic centre). Passageways through buildings were located and verified on site using OSM data in combination with surveys .The widths of the passages were estimated and subsequently implemented in the building shape file by cutting the respective polygons. In order to assure applicability in the whole municipality of Innsbruck the procedure to analyse vulnerability must be widely standardized. Hence all buildings were classified into 27 different object classes depending on their predominant function. In respect to vulnerability it was distinguished between four different (qualitative) classes, i.e. low, medium, high and very high.
To quantify the collective risk of a scenario a simple and pragmatic approach is introduced. Each object is assigned with a value according to its specific risk: low (yellow), medium (orange), high (red) and very high (violet). The cumulative sum of all specific risk values results in a dimensionless quantity, which allows to compare the flood risks of different scenarios. All buildings were designated with the specific risks according to the risk matrix.
The results of all scenarios computed can be visualized by the user through selection of the parameters shown. Also a statistics about affected and flooded buildings is shown according to the vulnerability.
Several combinations of adaptation measures have been analysed:
- network: the drainage network from the year 2000 and the year 2015
- infiltration measures: newly developed areas have been analysed for infiltration measures on-site. This results can be used for standard infiltration measures, but also the usage of water sensistive urban design (WSUD).
- analysis of the spatial distribution of the population. This enables for finding alternative ways of city development.
Risk: Scenario comparison