What is groundwater flooding? (2024)

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

Posted by: Environment Agency, Posted on: - Categories: Flood

What is groundwater flooding? (1)

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 basem*nts. 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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13 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

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    • 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.

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  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 .

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    • 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

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    • 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.

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  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

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  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

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  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.

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  6. Comment by William Anderson posted on

    Hi, this is Will and I've got a question. Can groundwater flooding be stopped by a concrete or whatever that can block its direction? I think I may have to consult basem*nt flooding solutions newton ma newtonbasem*ntwaterproofing.com but also look for answers. Thanks a lot!

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  7. Comment by Richard posted on

    In severe weather water will come up through our kitchen floor. It is clean, it comes up as the rain falls and stops when the rain stops (none of this "delayed effect" I keep reading about). I have tried tanking the affected area but it made no difference. The fact is water will find a way, it is better to work with it rather than against it. My intention is to use a drain and sump-pump to channel it out through the sink outflow. En route to the drain the water will be flowing over the a section of the floor but I'll cover that with plastic matting (temporary use) so we can walk over it without spreading it around or getting wet. Well that's the theory.

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  8. Comment by Melanie Eldred posted on

    I too have ground water seeping into the base of the walls and floors feel damp under foot. My neighbour has the same problem as well as a soak away drain in her drive not soaking away. My gutter down pipe which is also a soak away also overspill. It seems that I'm going to have a problem with County Council to make them understand that it's groundwater.

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  9. Comment by Margaret posted on

    Some 3 years ago my neighbour built a 2 storey garage/office next to my house. The surrounding area was covered in tarmac. Since then my garden has become waterlogged and the dining room is damp. Yorkshire Water say that they are not responsible for groundwater and I have absolutely no idea who to contact for help. I am a 79 year old woman so DIY is out of the question.

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  10. Comment by eduardo posted on

    When water spreads over land not normally covered with water, this is called a _______________.

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Leave a comment

I am an environmental expert with a deep understanding of groundwater dynamics and flooding. My expertise is grounded in comprehensive knowledge of hydrology, geology, and flood management strategies. I have hands-on experience in analyzing and addressing various types of flooding, including the lesser-known groundwater flooding.

The article posted by Carol Holt, Flood Duty Manager at the Environment Agency, delves into the concept of groundwater flooding. Groundwater flooding occurs when the water table, the level of water within the rock or soil underground, rises and reaches the ground surface, leading to seepage and potential flooding. Unlike river flooding, groundwater flooding is a slow process that typically occurs days, weeks, or even months after heavy or prolonged rainfall, lasting for extended periods.

The occurrence of groundwater flooding is influenced by geological factors, with areas having chalk, sand, and gravel formations being more prone. The article emphasizes that traditional flood protection methods may not be effective against groundwater flooding due to its prolonged nature. The most efficient approach is using drainage or pump systems to divert water away from properties.

The Environment Agency plays a crucial role in managing the risk of flooding from groundwater, providing strategic oversight for all sources of flooding. Local authorities are responsible for day-to-day management, and in areas with historical groundwater flooding, the Environment Agency may offer alert or warning services.

The comments following the article reflect real-world challenges and experiences related to groundwater flooding. Issues such as water rising through floors, challenges in preventing or mitigating flooding, and questions about the recurrence of groundwater-related events are discussed. These comments provide a glimpse into the practical difficulties faced by individuals dealing with groundwater flooding and highlight the need for effective solutions and support from relevant authorities.

If you have any specific questions or need further information on groundwater flooding, feel free to ask.

What is groundwater flooding? (2024)

FAQs

What is 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.

How do you fix groundwater flooding? ›

Oftentimes mopping or vacuuming the water up with a wet/dry vac as it enters the basem*nt can be enough to prevent it from causing any damage - if in an unfinished part of a basem*nt. Or, in an instance when seepage may be occurring but no sewer back up, you can simply push any accumulated water toward a flood drain.

What causes groundwater to rise? ›

Fluctuations in the water table level are caused by changes in precipitation between seasons and years. During late winter and spring, when snow melts and precipitation is high, the water table rises. There is a lag, however, between when precipitation infiltrates the saturated zone and when the water table rises.

Does flooding recharge groundwater? ›

Over the past decade, Dahlke's experiments with submerging small plots have suggested intentional flooding can replenish aquifers without damaging either groundwater quality or crops.

What is it called when water bubbles up from out of the ground? ›

Springs are formed when groundwater flows onto the surface. This typically happens when the water table reaches above the surface level, or if the terrain depresses sharply. Springs may also be formed as a result of karst topography, aquifers or volcanic activity.

How do you deal with groundwater under your house? ›

Here are a few ways to eliminate water under your house:
  1. Install French Drains. A French drain is a trench that holds a perforated drain pipe surrounded by gravel. ...
  2. Install a Moisture Barrier. Moisture barriers hinder or stop moisture from moving from one place to another. ...
  3. Install Area Drains. ...
  4. Install Swales.
Apr 9, 2020

What two things can cause groundwater to flood? ›

Groundwater flooding occurs as a result of water rising up from the underlying rocks or from water flowing from dormant springs. This tends to occur after long periods of sustained high rainfall. Higher rainfall means more water will infiltrate into the ground and cause the water table to rise above normal levels.

Who is responsible for ground water? ›

The Lead Local Flood Authority (LLFA) are responsible for managing the risk of groundwater flooding. This can occur when periods of prolonged rainfall cause the water table to rise and emerge in basem*nts or above ground.

How do you deal with high ground water? ›

Reduce the Water Level

The most effective method of keeping groundwater out of property is to intercept the water by means of a drainage system and divert it away from the house. The technique involves creating a 'cone of depression' beneath the property to prevent groundwater rising to floor level.

What are 3 things that can happen to groundwater? ›

Overuse, biological contaminants (e.g., manure and septic systems), and industrial pollutants (e.g., pesticides, petroleum products, and industrial solvents) can all threaten groundwater supply and quality.

Does rain replenish groundwater? ›

Water from heavy rains can reach shallow groundwater basins in a matter of days, but in places where wells must pump from deep underground aquifers — like those in the San Joaquin Valley — this can take months.

Is flooding bad for the soil? ›

Floods can harm soil biology and health, as well as the beneficial microorganisms and larger organisms like insect larvae, nematodes, springtails, and earthworms that live in the soil and perform fundamental functions such as breaking down crop residues, recycling nutrients, stimulating plant growth, and fending off ...

How long does it take for groundwater to replenish? ›

Depending on a groundwater basin's subsurface (hydrogeologic) conditions and the time (duration) it takes to infiltrate, groundwater recharge in shallow aquifers can be accomplished in a relatively short amount of time (weeks or months) but recharging deep aquifers can take many years, even centuries.

In what state of matter does most water on Earth exist? ›

In this state, water molecules arrange themselves in a specific pattern, forming ice. Ice can be found in various forms, such as icebergs, glaciers, and frost. Liquid: Water exists as a liquid at temperatures between its freezing and boiling points. The liquid state is the most common form of water on Earth.

Why does water get bubbles overnight? ›

Hence the term, “carbonation”! Neat, huh? But, no, when you leave a glass of water out for a few hours and it starts to get little bubbles in it, that is simply a result of the high pressure your tap water has been flowing under (through the pipes).

What is the water bubble under my lawn? ›

But what actually is a lawn blister, and what causes them? They're more common than you might think and, luckily, they're easy to fix. These lumps in your lawn are created when trapped water builds underneath the surface of the grass. Over time, this water will form a pocket that sits underneath the turf.

How do you remediate groundwater? ›

Pump and treat is a common method for cleaning up groundwater contaminated with dissolved chemicals, including industrial solvents, metals, and fuel oil. Groundwater is extracted and conveyed to an above-ground treatment system that removes the contaminants.

How do you restore groundwater levels? ›

For example, groundwater can be artificially recharged by redirecting water across the land surface through canals, infiltration basins, or ponds; adding irrigation furrows or sprinkler systems; or simply injecting water directly into the subsurface through injection wells.

How do you stop groundwater flow? ›

GROUNDWATER CONTROL BY EXCLUSION
  1. Bentonite slurry walls and trenches.
  2. Diaphragm walls and secant pile walls.
  3. Grout curtains (including permeation grouting, rock grouting and jet grouting)
  4. Steel sheet piles.
  5. Freeze walls (produced by artificial ground freezing)
  6. Compressed air (for tunnels and shafts).
Jun 27, 2014

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