Drainage systems - who's responsible?

Article by Andy Ainsworth 01 February 2017

It has never been easier for homeowners and businesses to take the first step in checking their flood risk. With over 5 million homes in England at risk of flooding from various sources including the rivers and the sea and just over half of these (2.8 million) being at risk of surface water flooding alone.

You can check your flood risk online here

Within rural areas typical weather conditions result in most rainfall being dispersed through a mixture of high rates of infiltration, evaporation and relatively low rates of surface run-off. However, the ongoing development of urban landscapes and the increase in hard surfacing is resulting in far less infiltration of water into the land and a much higher rate of surface run-off. This excess surface water is controlled and managed through the use of drainage. 

   Surface Water Diagram

Drainage systems

Highway drainage networks, sewer systems, land drains, soakaways and outfalls into rivers and water courses, all play a critical part in the distribution, removal and management of surface water. Some of the main problems collectively facing drainage systems include blockages, collapses, leakages and of course, over-loading. Not only are we experiencing wetter climates resulting in more rainfall, but we ourselves are contributing to the volume of surface water by placing an ever increasing load on existing drainage systems.

New housing development often see’s hectares of Greenfield sites removed and replaced with concrete, tarmac, roofing slates/tiles and paving, all of which collect and increase the volume of water entering drainage systems.

Most properties built after the 1920s are connected to two separate sewer systems; one for foul water and one for surface water, which is commonly utilised by highways drainage, and although the water companies are responsible for both the foul and surface water sewer systems, County Councils or Unitary Local Authorities are responsible for the connecting highway drainage infrastructure, such as drainage channels, pipe work, gullies and storm drains etc. When these systems exceed capacity, due to an increased load being placed on them, such as heavy rainfall, the result is surface water flooding.   

Surface Water Flood (1)

What can be done about it?

In the long term, developers of urban areas and road networks are all being required to give far more consideration and planning to the management of surface water and many are incorporating the use of Sustainable Drainage Systems (SuDS) in to the design and build process. SuDS aim to manage rainfall close to where it falls and are used to help slow surface water run-off, aid evaporation and the infiltration of water into the land as well as channel excess surface water towards soakaways, natural water storage basins and water courses.

More information on SuDS and how they can help reduce flooding can be found here 

In the short term, each of us as individuals can help play an important role in helping to look after drainage systems and reduce surface water flooding. Collectively, we need to be far more aware of what can and cannot be put down the drains and toilet. According to United Utilities, food, nappies, wipes, hair as well as fats and oils from cooking all contribute to more than 28,000 blockages a year in the North West alone.

Further information from United Utilities on what you can and cannot FLUSH down the toilet and POUR down the sink can be found here.

Blocked Drain With Leaves In

One of the most important things we can all do to help drainage and try and reduce surface water flooding, is to periodically inspect and clear drains in our local area and ensure leaves and debris do not cause blockages. Tradesmen and contractors should not pour plaster residue and other building waste down gullies in the street. Keeping these gullies open and free flowing will allow surface water to drain away and reduce the risk of surface water building up. 

Highways departments within County Councils and Unitary Local Authorities can prioritise hot spot areas for gully cleaning and maintenance in areas susceptible to surface water build up. In addition, Local Authorities and the Environment Agency can monitor and remove blockages such as trees in ordinary water courses and waste and leaves from trash screens on culverts. However, sometimes these agencies do need to be made aware of any potential problems and if in doubt, it’s always advisable that members of the public ensure they report any issues through to the correct agency.

Take a look at our infographic for further information on drainage systems and who is responsible for maintaining them 

Drainage Systems - Who 's Responsible (3)

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