15 Nov 2021
We have created an illustration of a portfolio comprising 1,000 properties in the Chichester region.
These properties were selected from a 600km2 area centred on Chichester on the South coast. The region was selected as containing flooding representative of all four main sources of flooding from coastal, river, surface water and groundwater sources.
The purpose of this selection is to illustrate:
Finance Use Case
The property lender (bank, loan book etc) has a portfolio of 1,000 property loans in Chichester for which the property is collateral. The lender now wishes to understand the exposure of these properties to the different types of flood – the impact of a climate change scenario.
The results of this study could assist the lender, as follows:
FloodSmart Analytical Portfolio Results
We show our results in a table, by portfolio selection method (peril choice(s)) and then by exposure (peril values). Values have been established using the GeoSmart FAST* model to derive flood depth, probability and duration. FAST uses GeoSmart’s latest groundwater flood depth model, combined with data from the Environment Agency on the risk of flooding from surface water run-off, rivers and the coast.
This information, combined with our digital terrain model (DTM), supports a calculation engine that generates a probability distribution of flood depth and likely duration. A cost calculation is then performed, based on flood depth and property type to provide an indication of economic or financial losses for each event and as an average annual damage (AAD).
The case study uses an engineering calculation, assuming an average residential house following a similar approach to the Environment Agency, which can be cross referenced against actual claims data. The benefits of flood defences are excluded from the case study results.
The costs resulting from each type of flooding are available separately or as a combined AAD flood index. Clients also have the option to provide their own property and cost data or export data into their own cost models.
FloodSmart Analytics uses GeoSmart’s significant technical hydrogeology and related expertise, which is contained in its proprietary flood model – FAST (Flooding from All Sources Tracker).
Basic view – FAST Model Results
Climate Change View – FAST Model Results
The climate change view – with same portfolio selection to show a constant comparison at each specific property – which might have led to a different portfolio choice if starting from scratch under this scenario. It should be noted that an alternative climate change scenario will also change the area, severity and mix of flood types.
Climate change assumptions:
The following assumptions were made to illustrate the potential impacts of climate change. River and coastal flooding levels were raised by 0.5m and surface water flood levels were increased by 15cm and groundwater flood levels increased by 5cm.
Portfolio – zoom in details of central map area centred on Emsworth town – show that each policyholder property is identifiable, regardless of the size of the portfolio selected.
Emsworth – extreme location view