The Great British Summer has once again been the subject of an incredibly wet few weeks, with flash flooding seen across many areas of the country.
At Groundsure we love to analyse and verify the data we use and these events have given us an opportunity to do so.
Within Groundsure’s suite of reports, a variety of data is utilised from providers including the Environment Agency, JBA Risk Management and the British Geological Survey. This analysis will focus on the surface water flooding data provided by market leading flood specialists JBA Risk Management.
It is estimated that around 2.8 million properties in England and Wales are at some risk of surface water flooding and many of those homeowners have no idea of the associated risks.
Surface water flooding, often referred to as a pluvial flooding, is caused by overland flow before the rain water (runoff) enters a watercourse or sewer. It is usually the result of intense rainfall, but also occurs when the land has a low permeability commonly due to the urbanisation of an area. Surface water flooding is increasingly becoming a serious problem in towns and cities due to the large scale of poorly planned developments, as the water has nowhere to go and ponds and puddles in depressions.
Groundsure’s data verification:
Tunbridge Wells, Kent
Silverdale Road looking towards Upper Grosvenor Road
Silverdale road was subject to surface water flooding on 24th August 2015 as can be seen in the photograph above and verified by Groundsure’s surface water flood data.
Hoopers Department Store, Mount Pleasant Road
Other areas in Tunbridge Wells that were affected including Hoopers Department Store located on Mount Pleasant Road.
Long Bennington, Lincolnshire
Acklands Lane, Long Bennington The Royal Oak pub, Long Bennington
In another part of the country, Long Bennington in Lincolnshire was the subject of numerous flood events including Acklands Lane and The Royal Oak pub.
How can Groundsure help?
Finding out if your property is at risk of flooding could you save you time and money as well as ensuring you and your property are protected. Even if a property is not at risk of flooding from rivers or the sea, you could still be at risk from surface water flooding.
Groundsure has chosen to use JBA’s surface water data as it’s based on a digital terrain ‘bare-earth’ height model and allows for the assessment of site-specific flood risk. We choose to use this data over any other provider as it allows our clients an instant view of risk without the need for any additional information.
Other surface water datasets are not always site specific and therefore cannot provide an accurate risk assessment for your client’s property or site; instead these should be used for high level comparisons such as comparing risk between towns and counties.
Jill Boulton, Director at JBA, said: “We are happy that clients can access JBA’s industry leading surface water flood map for Great Britain through Groundsure. The map captures the effects of spatially dependent rainfall within each 5km2 grid tile across England, Scotland and Wales, and is modelled at 5m resolution. It provides extent and depth data for multiple return periods and takes into account the flooding characteristics of both steep and flat terrains. For example, because intense rainfall creates flooding more quickly on steep ground than on flat, we model storms of only one hour’s duration. Flat ground takes longer to flood so, to capture this, we also model storms of ten hours’ duration. By the time we have made adjustments to allow for infiltration into the ground and drainage in urban areas, as appropriate to land use, we are pleased to offer an indicative surface water map of unmatched quality.”
This article was submitted to be published by Groundsure Ltd. as part of their advertising agreement with Today’s Conveyancer. The views expressed in this article are those of the submitter and not those of Today’s Conveyancer.
