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https://environmentagency.blog.gov.uk/2019/12/23/what-is-groundwater-flooding/

What is groundwater flooding?

Posted by: , Posted on: - Categories: Flood

flood sign in front of flood water

By Carol Holt, Flood Duty Manager at the Environment Agency

So far this autumn it has been exceptionally wet across large parts of the country with many records being broken and widespread flooding.

But have you ever wondered about the different types of flooding? Most people probably associate flooding with scenes of rivers bursting their banks or dramatic waves and spray from coastal flooding. You will definitely have come across surface water flooding – put simply – when rain from heavy rain overwhelms drains, causing disruption, often to roads. But there’s a fourth and lesser-known type of flooding called groundwater flooding.

Flooding from groundwater can happen when the level of water within the rock or soil underground – known as the water table – rises. When the water table rises and reaches ground level, water starts to seep through to the surface and flooding can happen. This means that water may rise up through floors or underground rooms such as cellars or basements. Water doesn’t always appear where you would expect it to - such as valley bottoms – it may also emerge on hillsides.

Groundwater flooding is much slower to occur than river flooding – it will usually happen days, weeks or even months after heavy or prolonged rainfall. And it may last weeks or even months.

Flooding from groundwater is most common in areas where the underlying bed rock is chalk, but it can also happen in locations with sand and gravel such as in river valleys. Some parts of the country are more prone to groundwater flooding than others – such as Dorset.

We reduce flood risk in many ways, including building flood defences, working with our partners to increase resilience to flooding and through maintaining rivers. But one of the many challenges of groundwater flooding is that many traditional methods of flood protection may not be effective against flooding from groundwater. This is because water can come up through the floor can continue to do so for a long time.

The most effective way to keep groundwater out of your property is to use a drainage or pump system to divert the water away from your home or business. For more information visit our website: https://www.gov.uk/government/publications/flooding-from-groundwater

Local authorities are responsible for managing the risk of flooding from groundwater. However, the Environment Agency has a strategic overview for all sources of flooding and in some areas that have historically experienced groundwater flooding, the Environment Agency provides a groundwater alert or warning service.

For more information about how to stay safe in a flood visit: https://www.gov.uk/check-flood-risk

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8 comments

  1. Comment by George Jackson posted on

    It can take weeks or months before water rises through the floor. If I had a warning that I should leave my house and stay in a public building or such like for a prolonged period, I would simply seal the bottom half of my doors with my silicon gun and the same with any vent bricks. After the the prolonged period I would break the seal with a Stanley knife and walk in to my bone dry house. Yours sincerely, George Jackson. georgeandsheila.jackson@gmail.com

    Reply
    • Replies to George Jackson>

      Comment by K Higgs posted on

      The water comes up through the floors. Sealing doors and vents will not stop that! It also happened within hours of local flooding, there was no warning.
      In our case it came up in the middle of the property first. No amount of boarding or sandbagging helped in the end.
      The water subsides as quickly as it arrives. In comparison to our neighbours who delayed remedial action, we cleaned out immediately, installed dehumidifiers within 48hrs and saved our home. Our neighbours homes are destroyed as they left it weeks.

      Reply
  2. Comment by Diane Wilks posted on

    I am interested to know if underground spring water can rise every morning for 3 hours and then subside. This event has happened under my drive for the last 3 months. There was exceptional rainfall 5 months ago. We have piped it away to avoid problems but it is still occurring .

    Reply
    • Replies to Diane Wilks>

      Comment by eileenroffe posted on

      Good morning, please email our email management unit who will log the email and forward to the area team. Please include a full address and postcode and a daytime telephone number: enquiries@environment-agency.gov.uk - thank you in advance - Eileen

      Reply
    • Replies to Diane Wilks>

      Comment by Susan Scott posted on

      This is happening to me also, when it rains there is a little hole in the ground and water bubbles up and floods my drive.

      Reply
  3. Comment by Cheryl posted on

    Underground water/spring has surfaced within my property boundary. Water now seeps out at the base of a retaining wall in the garden and water enters my kitchen in a corner of two retaining walls. As fast as I wet/dry vacuum up the water, it reappears at pace. My neighbour has water entering her property too at the party wall. This started on Thursday 13th August. The Local Authority nor Environment Agency seem to be interested and have offered no support. What can we do?
    Cheryl

    Reply
  4. Comment by Laura Young posted on

    I know the feeling since January 2020 when visible dirty water came through the floor, no amount of drying has help. My house has physical DPM and I'm on hill, ochre staining my paths but noone wants to know or help.
    The significant removal of trees and 3 mine shafts on the land behind its a joke! Higher than normal chlorine levels in drinking water! Makes for book, I know why as part of the general public we have lost confidence in a system set up for justice. Has anyone some ideas? I need help

    Reply
  5. Comment by Ben Smith posted on

    A housing development was built on a field that held standing water for most of the year. Now surrounding housing has gardens that are waterlogged most of the year and mostly unusable except for a couple of month. The building is still in progress with huge craters visible holding water....these areas are planned for houses. In effect the planning department has destroyed people's lives as we will be unable to sell homes due to inherent problems caused by waterlogged/ flooded land. Surrounding houses are timber framed so added problems as they rot.

    Reply

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