Understanding groundwater
In 2013 GeoSmart was formed out of ESI, an environmental consultancy specialising in water, land and sustainable development. GeoSmart now focuses on flooding in the UK, with a specialism in modelling groundwater flood risk.
Groundwater flooding occurs when water under the ground rises to the surface. Underground rooms, such as cellars and basements, are particularly at risk. This type of flooding is slow to occur – it will usually happen days, weeks or months after heavy or prolonged rainfall.
Groundwater also makes an important contribution to river flows and has a large influence on the likelihood and severity of flash flooding.
Despite the significant risk that groundwater poses, it is much less widely modelled than other types of flooding. Paul described how GeoSmart is helping insurers understand the full scope of potential flood losses.
Groundwater is an important and often underappreciated source of flooding. But modelling this type of flood risk is complex. GeoSmart has invested in producing a high-resolution national groundwater emergence map.
The underestimated risk
Recent research from GeoSmart has found that 5% of all homes in Great Britain are at risk of groundwater flooding. Hotspots include London, Kent, Surrey and Yorkshire among others. It is a similar number of locations to those threatened by river (also known as ‘fluvial’) flooding.
“A flood risk analysis which excludes the groundwater component may underestimate risk severity. As well as potentially increasing the depth of flood waters, groundwater flooding lasts for much longer. Floodwaters which persist for a long time are substantially more damaging. Buildings, interiors and contents are often irreparably damaged due to mould and rot.”
Paul explained another challenge with groundwater flooding:
“Groundwater is also harder to defend against. A fluvial flood defence may keep the river at bay, but if the groundwater table rises behind the defence then flooding will still occur. This residual risk is often overlooked.”
Creating a coherent view of flood risk
Whilst GeoSmart specialises in groundwater risk assessment, it recognises that all types of flooding are linked. Through its flood modelling tool, FloodSmart Analytics, the company provides data on all sources of flooding, including river, flash flooding, tidal and groundwater.
GeoSmart is able to provide detailed risk analysis at an individual property level with in-depth flood risk reports on specific properties. The analysis identifies predicted flood depths at multiple return periods for each flood source – separately and in combination. Predicted losses are calculated based on a vulnerability assessment which also considers the duration of flooding. Risk index data is quantified, which considers flood risk with and without the benefit of flood defences.
Detailed analysis such as this can be used to create entire portfolio risk assessments. The company’s high-resolution flood maps, which underpin its assessments, are licensable for insurers that want to perform their own analysis.
The company has also built a flood data visualisation tool which can show flood maps and risk exposure at any UK location.
Groundwater flood forecasting
Alongside its flood risk data, maps and desktop reports, GeoSmart offers a groundwater forecasting service. Groundwater has a seasonality to it, with levels dropping in summer and rising through the autumn. Using high-quality historical data, GeoSmart is able to accurately predict future states based on forecasted rainfall.
The company provides advanced warnings of the time, location and severity of groundwater flooding. This lets clients plan mitigation and flood response activities.
The company’s forecasting services tend to be used by water companies to manage flood risk and mitigate sewer overflows. But GeoSmart is seeing growing interest among insurers in using these forecasts to warn their policyholders.
Quantifying the impact of climate change
Another area the company is seeing a lot of interest is its climate change projections.
“GeoSmart determines the impacts of climate change on UK flood risk under a range of scenarios. We consider this separately for each source of flooding, with enough resolution to account for regional variations in climate. We believe that we are the first organisation to quantify how a changing climate will impact groundwater flooding.”
Connecting with GeoSmart
Whilst GeoSmart’s customers have traditionally been property developers, planning consultants and solicitors, the company is expanding its reach in the financial and insurance sectors.
“We would like to speak to companies who currently use flood data and are interested in an alternative view of risk. GeoSmart can be used to augment an insurer’s current view of risk with an enhanced understanding of groundwater.
“Alongside insurers, reinsurers and brokers, we would like to hear from data aggregators. If there is an interest in offering our data through third-party platforms, we would be keen to connect.”