Case Study: Flood Survey
Client: A global insurer of art and valuables
Objective: Undertake detailed flood risk surveys at 7 properties which had been ranked by the insurance company as being at the greatest flood risk using off-the shelf risk management products available for the insurance sector.
Actions: The surveys commenced with a desk-based study involving a detailed collation of background environmental information at each of the property locations. We analysed data from published sources including historical flood risk information from the British Hydrological Society, extreme rainfall records from BRDA and flow records from the National River Flow Archive. We reviewed geology, soil and topographic maps, as well as overall flood risk information from the Environment Agency.
The desk-study component was then followed by fieldwork at the property to identify all potential points of water ingress; measure the ground/floor levels at key locations to Ordnance Survey datum; identify all water features within the vicinity of the property and any measures which have been put in place to reduce the risk of flooding.
In locations where the Environment Agency had not undertaken any detailed flood modelling and mapping, we performed hydrological modelling using methods from the Flood Estimation Handbook and applied hydraulic modelling techniques to estimate the design flood flows and levels at the site.
Outcomes: Hydro-GIS’ surveys found that only one of the seven sites had a high risk of flood. Three of the sites, which had previously experienced flood risk, had successfully incorporated measures to reduce the risk of flooding. At the remaining three sites, the flood risk was clearly low. Overall, the work undertaken by Hydro-GIS identified to the client the inaccuracy of the original risk management data which had been used.