Flood risk is a growing problem in the UK where five million homes are at risk of flooding, according to the Royal Institution of Chartered Surveyors. Climate change is causing increasingly unpredictable weather patterns and the rising incidence of severe rainstorms means that flooding is a major issue affecting homeowners, housing developers and government.
This article covers the following topics:
• 10 tips to help prepare for flooding
• 8 solutions to prevent flooding
• advice on drainage to prevent flooding
• how to deal with the aftermath of flooding
• insurance and flooding
• new housing development and flooding
10 tips to help prepare for flooding:
1. Find out if a property is at risk by registering with the government system, Floodline, by visiting the website or calling 0345 988 1188. Registration is free and Floodline will notify householders of any flood risk in their area via mobile phone, email or landline.
2. Check that the property is insured against water damage and the associated costs of drying out, temporary rehousing, restoration and professional fees.
3. Prepare a flood kit and flood plan: the kit might include insurance documents, torch, 1st aid kit, warm clothes, bottled water, snacks, baby supplies, medicine. The flood plan should include key contact numbers and details of how to shut off gas, electricity and water.
4. When renovating, add a waterproof coating to walls, opt for tiled floors rather than carpets downstairs, install power sockets and other electricals at least 1.5m above floor level, add flood guards to windows and doors, ensure ventilation bricks have covers, landscape the garden so that water flows away, install one-way valves on toilets and drainage pipes to prevent sewage backing up into the house and install wall to floor membranes. Temporary seals can be placed on doors, windows and air bricks.
5. Install a sump pump, obtain flood barriers and flood protection equipment. Have emergency sandbags and flood boards ready to fit around windows and doors in the event of a flood.
On receiving a flood warning:
6. Turn off gas, electricity and mains water.
7. Place sandbags around the house perimeter.
8. Put plugs in sinks and baths and weigh them down with sandbags. Plug any other water inlets such as overflows, taps and toilets.
9. Move valuables and portable items such as electronics upstairs.
10. Ask for help when preparing for a flood and consider vulnerable neighbours.
8 solutions to prevent flooding
Flood barriers: The Environment Agency uses a range of temporary demountable flood barriers which are lightweight and portable. Sectional barriers, made from steel or a similar material, are dug into a foundation and seals are used to prevent water passing through, while frame barriers use the weight of floodwater to hold them in place. Temporary barriers can also be added to these systems, such as glass barriers on raised embankments.
Natural flood management: This involvessteps to reduce the flow of floodwater before it can reach main rivers, such as building small barriers in ditches and fields, cutting into embankments to divert water to open land, and letting water form pools outside the main channel to reduce the amount of flow from the flood.
Tree planting: While trees help take water from the soil, large numbers of trees are needed to have any effect.
Felled trees: These can be laid across streams in woodland areas to help divert water into the surrounding ground.
Wetlands: Creating wetlands is beneficial as they act as sponge, absorbing water.
Sustainable drainage systems (SuDS): This technique is often used in towns and cities prone to flash floods; the aim is to manage stormwater as close to its source as possible by imitating natural drainage, especially around development. The systems work by holding back and slowing water run-off from a site, allowing natural processes to break down pollutants and prevent flooding and water pollution. Such systems can also recharge groundwater to help in drought.
Infiltration: Housingdevelopments should be landscaped so that water from roofs and driveways seeps into open ground rather than the water system, through infiltration. Detention basins can be built to collect and hold rainwater, helping manage the volume of water entering urban rivers.
Dredging rivers: This methodremoves silt: a build-up of sand, clay and rock particles which has built up on the riverbed. It requires an excavator or vacuum pump and while it can improve land drainage, the Environment Agency says that it cannot prevent rivers from flooding. It is a costly technique and may harm the environment by damaging riverbanks. After flooding, repeat dredging may be required.
How does poor drainage cause flooding?
Floods are commonly caused by blocked drains, collapsed pipework or badly planned systems. Regular maintenance of drains is vital and it may be prudent to replace a poor system to reduce risk; consider the following:
◊ Blocked drains. Indicators include slow flowing water and smell. Blockages can be identified by using a CCTV drain camera.
◊ Cracked pipes can lead to slow leakage and eventual flooding; early intervention could pay dividends.
◊ Excess groundwater. Standing groundwater following rain may indicate a problem with the drainage system. Pipes may be too small to cope, or there may be a blockage. It is important to identify the cause to prevent structural damage to a property.
◊ Collapsed drains can quickly result in flooding and may need replacement or repair. Pipes usually crack before they collapse, and it is beneficial to make early repairs.
◊ A drain survey will identify cracks, blockages, leaks and is a quick way to locate the problem and assess remedies.
How to recover after a flood
• A householder should contact their insurance company.
• Take photographic evidence of the floodwater and damage as soon as is practical.
• Check to ensure that it is safe to return to the flooded property; a safety inspection may need to be carried out by utility companies before gas, electricity and water should be turned back on.
• Before cleaning and repairing, obtain advice from specialists. Insurance companies will appoint professionals to carry out much of the work. Be aware that there may be sewage and chemicals in flood water.
• Contact the local flood action group, flood warden and local authority.
• Consider reducing future flood risk by obtaining a Property Level Protection (PLP) report. This provides homeowners and professionals with practical, cost-effective measures to help reduce flood risk by using certain products. The report considers the use of building materials and offers solutions such as use of water-resistant mortar on bricks, providing vulnerable homes with a portable pump to remove floodwater or installing a sump pump to help remove water below ground.
Flooding and home insurance
The number of householders experiencing difficulties insuring their property due to high flood risk led to a joint initiative between government and the insurance industry which aims to make flood cover part of household insurance policies. Every insurer offering home insurance in the UK must pay into the Flood Re scheme; the £180m levy created each year is used to cover flood risks in home insurance policies. A homeowner buys home insurance in the normal way and an insurer can choose to pass the flood risk element to Flood Re for a fixed price. In the event of a claim the insurer pays and will be reimbursed by Flood Re. The scheme applies to houses built before 2009.
Changes have been made to the scheme which allow flooded households to receive money for carrying out flood protection measures such as air brick covers, flood doors, flood-resistant plasterboard to make homes more resilient, and possibly make them eligible for lower premiums. The government aims to see 336,000 homes better protected by 2027, helping avoid billions of pounds of damage to the economy and reduce the national flood risk by up to 11%.
New housing developments and flooding
Developers are required to provide a specific flood risk assessment (FRA) for any new property developments according to the National Planning Policy Framework (NPPF), paragraph 167, footnote 55. These site-specific FRAs reveal any risks created by the development, how they have been considered in the planning process and how flood risk will be managed throughout the build, from initial site digs to key handovers. The FRA will also examine whether flood risk is increased elsewhere by the development, how this is being managed, and in case of a flood, the predicted level, anticipated duration, velocity and depth of the water. FRAs also assess the frequency of flooding and amount of warning time given before the flooding.
The NPPF states that new developments should have a flood risk assessment for sites in Flood Zones 2 and 3. For Flood Zone 1, an assessment should accompany all proposals involving land identified by the Environmental Agency as having critical drainage problems or at risk of future flooding. Site viability should be determined by assessment of flood risk and development use.
The Meteorological Office weather pattern tracking system shows that heavy rain episodes are increasing. Climate change is leading to rising global temperatures, causing more extreme weather and increasing the likelihood of flash floods as warmer air can hold more water. With one in six homes in the UK at risk of flooding, flood risk has made many homes unsellable. Research by the Climate Coalition found that two thirds of people with homes on floodplains are concerned about the resale of their home, and 58% of the public would be concerned about buying a house on a floodplain. Despite this, houses are still being built on floodplain due to the pressure on councils to allocate land for development; Flood Zone 3 land is often the only option available. This has even led to homes being built with flooding in mind, by raising the lower levels of houses above any expected flood level and using these levels for storage and garaging rather than living space.
The government is spending record amounts on flood defences in England; £5.2 billion is to be spent over six years, with most directed at vulnerable regions. The Environment Agency is to spend £860m in 2022 towards 1,000 schemes with major funding targeted at Yorkshire, the Humber and the Northwest. Flooding is clearly an ongoing and complex issue for homeowners, builders, insurers and government, all of whom must factor in the challenge to accommodate future risks.
What do you think about future flood risk?
If you would like to make a comment, or would be willing to share your experience of a flooding event, do get in touch.