What is Surface Water?
Surface water is any body of water found above ground. It includes rivers, lakes, streams, and oceans.
Surface water is essential for our survival. However, too much of it can be detrimental. In the UK, we have learned this lesson the hard way. Flooding and extreme weather events are becoming more common, and many of us have experienced heavy downpours, if not direct flood damage.
Discover more information on what surface water is in our article ‘A Guide to Surface Water Drainage and Flooding’.
What damage can surface water cause?
Widespread flooding from surface water can pose a significant threat to water treatment facilities and essential drainage infrastructure.
As a result, properties can flood due to overwhelmed sewers, leading to increased pollution. Surface water floods can have a knock-on effect, leading to events such as airports closing, railway lines being washed away, agriculture facing serious challenges, and housebuilding projects being put on hold
What causes surface water flooding?
Surface water flooding occurs when the ground or drainage systems become overwhelmed and are unable to absorb or effectively carry away the water.
Surface water flooding can be caused by:
- Heavy rainfall
- Poor drainage systems & infrastructure
- Impermeable surfaces
- Blocked water courses
- Climate change
The recent UK Government budget plans announced a record two-year investment of £2.65 billion in flood and coastal erosion risk management, covering the period from April 2024 to March 2026.
Although these plans should help manage surface water flooding, we can identify climate change as a major contributor to surface water flooding.
Who is responsible for surface water flooding?
It’s a tricky one. Water and sewerage companies (WaSCs), local authorities (LAs), and the Environment Agency (EA) all have a part to play, and their responsibilities often overlap.
The WaSCs spends millions on reducing flooding risk for properties every single year.
In reality, overwhelmed flood defences are beyond the control of the water firms, whose sewer systems can’t handle the enormous amount of water during severe weather. Responsibility here rests with the EA, which is ultimately overseen by the national government. And, of course, Highways and local government have to answer the call when it comes to flooded highways, byways and other public areas. Regardless of the authority, meeting demand going forward will be a significant challenge.
According to the EA, the average annual cost of damage from flooding in England is more than £ 1 billion. This cost impacts homeowners, businesses, central and local governments and insurance companies.
A preventative strategy is essential. New technology has also enabled the EA to publish sophisticated maps that show which properties are now at risk of flash flooding (i.e., from overwhelmed surface water systems rather than river and coastal overspills).
How can we mitigate surface water flooding?
Years of urbanisation and the concreting over of land mean there is less green space to absorb the rainfall.
This means there needs to be an increasing focus on sustainable urban drainage systems (SUDS), which involves measures such as permeable paving, increased vegetation and water butts to slow down the rate at which rainfall enters the sewers.
Planners and builders have to get on board. Taking into account the risks a development will face, developers must mitigate potential damage, wherever possible, by capturing water and holding up runoff through green and brown roofs, porous paving, and holding tanks.
Competent builders will examine concrete floors, door guards, install electrical services above ground level, place attenuation (holding) tanks underground, and even raise the land level and floors.
All these measures may help reduce the risk of flooding by lightening the load on a wastewater network stretched beyond its breaking point due to the effects of climate change.
The Met Office is working with the industry to help it understand what to expect and to manage issues such as bursts, leakage, demand and turbidity and mitigate for changes in weather patterns.
With Yorkshire Water, for instance, it carried out a detailed review of how weather influenced all areas of their business and, as you would expect, found that air temperature and rainfall had the potential to cause the most significant disruption.
How well WSCs manage surface water depends on their networks being able to cope with the volume thrown at them.
It goes without saying that problems come when supply exceeds demand and systems are overwhelmed. Many kilometres of sewers are being renovated or replaced each year (we should know, because as a no-dig technology specialist, we are often involved), but it is an uphill struggle.
While the WSCs plan 20, 30, or maybe 40 years ahead, we should at least attempt to mitigate disasters in our own backyards.
Highway surface water drainage
Highway drainage plays a key role in overall road safety and efficiency. The Highways Agency (HA) has been tasked with improving journey time reliability as part of the Water Framework Directive (WFD).
Factors like congestion, accidents, and flooding are all under close scrutiny because they impact travel times. To reduce the risk of flooding, which is often referred to as 'ponding', it’s essential that all roadside drainage systems (including aco channels, gullies, and interceptors) function effectively.
Fortunately, we offer highway drainage cleansing services at various levels.
We service everything from motorways and A-roads for the Highways Agency to local B-roads through local councils.
Much of our work involves pre-planned maintenance, such as clearing grates and gullies of leaves, silt, and debris, jetting, and conducting asset surveys when necessary. Additionally, we hold contracts with numerous public and private clients that have large sites, including shopping centres, supermarkets, petrol stations, schools, and universities.
Our aim is to help them maintain their surface water assets in optimal working condition. Every little effort contributes to the bigger picture.
Discover some of the work we do for planned highway services in our article ‘Highways and byways: Prevention is better than cure for gullies’.
Rail surface water drainage
Railways are not immune to flood damage. Even when a rail isn't completely washed away, people often assume that once the water recedes, train service can resume immediately. This isn't the case.
Flooding can cause electrical circuits to fail, and water can accumulate in the ballast, affecting the track's stability and geometry. This can shorten the track's lifespan over time.
Fortunately, we have stepped in with our rail drainage services to help by clearing and cleaning the trackside drains that get clogged with silt after flooding. We also perform CCTV inspections to ensure the drains are structurally sound.
Discover some of the work we have provided for railways in our article ‘Rail culvert clearance proves the power of water jetting’.
What can you do to prevent surface water flooding?
Blockages in sewers can lead to backups and flooding, even without heavy rain.
To prevent this, it’s essential to keep drains and sewers clear, which calls for good housekeeping. However, it’s not just about maintaining the systems; using them correctly is equally important.
It’s ironic that water service companies have to spend their budget on education when that money could be better spent on infrastructure improvements. A key issue to remember is FOG, which stands for fat, oil, and grease. The formula is simple: if you put fat, oil, and grease down your drain, you will end up with blockages. We should all follow the advice to “bag it and bin it.”
Discover more information on FOG in our article ‘What can you flush down the toilet and drains?’.
Maintenance is also critical. During floods in Yorkshire and Humberside, while Lanes’ jet vac teams worked to assist struggling homeowners and businesses, one local school managed to stay open due to a proactive drainage maintenance program. This serves as an important lesson. Recognising the need for better planning, Humberside County Council implemented a strong maintenance program, which was a smart decision.
Our recommendation is to start with annual cleaning to remove silt from drains, followed by a CCTV survey.
For commercial and industrial sites, a survey every three to five years is advisable, based on the area, water table, and number of trees nearby. Once you have the survey results, take action to clear blockages and fix any damage in your drains.
We offer a comprehensive range of drainage services, including CCTV surveys, drain cleaning, jetting, vacuumation, and repairs, as well as no-dig technology.
What is the surface water runoff law in the UK?
The Flood and Water Management Act 2010 created a legal framework for managing flood risks, including surface water runoff.
It outlines the responsibilities of local authorities and the Environment Agency (EA) in managing these risks.
Key points of the Act include:
- New developments must use sustainable drainage systems (SuDS) to handle surface water runoff, unless it is technically impractical to do so.
- Local authorities can adopt and maintain SuDS for new developments.
- Developers must present their plans for managing surface water in their drainage strategies before they can obtain planning approval.
Looking for emergency flood services or preventive maintenance?
We offer a comprehensive range of drainage services and are taking extra steps to combat flooding through our partnership with Aqua Sentry, a specialist in pollution prevention.
Aqua Sentry provides innovative monitoring and closure device technology that helps organisations meet IPPC guidelines and ISO environmental standards. This technology is also proving to be effective in flood defence.
In the unfortunate event of flooding, we are available 24/7, 365 days a year to assist. With a fleet of advanced jetting and vacuum tankers available throughout the UK, we can respond quickly to emergencies.
We can also transport equipment wherever it's needed. Our pink fleet often serves as an essential emergency service to help manage rising floodwaters.