Groundwater risk management and flooding

When it rains heavily for prolonged periods, the risk of groundwater flooding is much greater. The ground becomes saturated causing the water table to rise, leaving nowhere for the additional water to go. Groundwater flooding is not confined to fields and countryside - in urban areas it can result in flooded roads, cellars and basements, causing property damage and disruption.

In April, government agencies completed a project on ‘Groundwater flood risk management in England’, which found that the water companies are already working together and sharing data with the Environment Agency and other organisations to tackle the problem, although there are inconsistencies across the country and limited guidance on how to mitigate the risks. The authors concluded that more needs to be done to collect and review data, along with more guidance and training on the implementation of groundwater flood mitigation schemes.

What’s needed to decrease the risk of groundwater flooding?

A rainy day in London recently highlighted what can happen when groundwater is overwhelmed. Videos of cars driving through floods on the iconic Tower Bridge were seen around the world and prompted calls for steps to be taken to mitigate further groundwater flooding. The Green Party urged London’s Mayor to plant more trees and create more green spaces to absorb the extra rain.

The Woodland Trust has concluded that, when estimating surface water run-off in urban areas, trees reduce run-off by 80% more when compared to asphalt - over the past few years, more householders have paved over their front gardens to give them a place to park their cars, and more people are paving over their back gardens or using artificial grass in order to minimise the amount of work that needs to be done, which also contributes to groundwater flooding.

In flood-hit Calderdale, the Forest of Bradford, the Woodland Trust and Yorkshire Water have combined efforts to plant a million trees as a flood prevention measure. Towns in the Calder Valley, such as Hebden Bridge, have suffered greatly from repeated flooding in recent years, prompting natural flood management measures which also include hedge planting, dam repairs and bog restoration.

Mitigation of groundwater flooding

The Environment Agency (EA) has assessed ways of mitigating groundwater flooding in areas served by aquifers. Pumping the water is impractical because of the large volume of water involved and the lack of suitable areas to pump the water to. Creating overflow channels to divert flood water from the area and dealing with narrow pinch points will provide effective solutions, but the EA’s main recommendations were for the formation of local action groups and the implementation of measures to protect buildings against flooding and flood damage.

How you can protect your business from flood damage

The aftermath of flooding is often very costly and typically involves replacing many business assets. The good news is there are several inexpensive tips that you can implement to help protect your business from a flood:

• Store expensive business equipment and important documents on upper floor buildings or on shelves and tables on ground floors.
• Landscape around your business premise or use permeable surfaces in car parks (e.g. gravel) to help improve surface water drainage.
• Ensure main entrances and outside doors have flood barriers.
• Keep any vehicles in garages or storage units on site or park on higher ground near the business premise.
• If your business is located in an area which has a high risk of flooding, consider installing sump pump water drainage systems.