Thames Water: We need your help in Lambourn

8 March 2024

A letter from Thames Water to the residents of Lambourn

Hello,
We have asked for your support in the past with our Bin it don’t block it campaign, can we have your help again to stop unflushables being put in the sewers and finding their way onto the streets in the flooding that we are trying to manage and is made more challenging from this debris.
Groundwater levels in Lambourn are the highest they have been in 30 years, and we’ve had one of the wettest 12 months on record.
The wet weather has overwhelmed our sewer network with groundwater, surface water and flood water, which gets into our pipes via infiltration by sewers and manholes as well as getting in through privately owned drainage pipes. Some of the extra flows we are seeing also enters our network from mis-connected roof drainage.
Because rainwater soaks into the ground slowly, groundwater levels can continue to rise long after the rain has stopped. This means it will take a long time for the extra water to leave our system, even once the rain stops.
We are aware of the impact this has had on the village and we apologies for any inconvenience this has caused, our primary concern is to stop flooding and any environmental impact.
Our investigations have highlighted the number of inappropriate items such as wet wipes, sanitary products, and cotton buds etc. These cause blockages in the filter unit located on Newbury Street and can stop the sewage pumping stations and treatment works from doing their jobs properly. As you are seeing, these items also impact the village when the manholes overflow. We are carrying out daily clean-ups, however once we’ve finished these non-flushable items are appearing again in the cleaned area almost immediately.
We are working hard to keep our sewers flowing and prevent flooding, but these non-flushable items are making this harder, so it’s important we all follow the guidelines.

How can you help?
Sewers are only designed to take away water, toilet tissue and human waste – everything else belongs in the bin. With your help we can reduce these unsightly items spilling onto your streets.

• Do not flush wipes down the toilet, even if they are labelled as ‘flushable’. They’re
  made of plastic and won’t break down like toilet tissue.
• Nappies and sanitary products belong in the bin, never down the toilet. They will clog
  pipes and cause blockages.
• Never pour fat or oil from cooking down the sink. Let it cool, pour it into a container
  and put it in the bin. Please remember: Bin it – don’t block it.
  
  What did we find?
  To help illustrate the problem, we have provided photos from our filter unit and an area where the
  sewer is flooding. Large amounts of paper and rag, including wet wipes, kitchen/hand paper towels and sanitary products are being removed from these locations daily and the temporary filter unit we are using in the village the needs regular cleaning.
  
  Find out more
  If you would like any more information or would like to order some of our free fat traps to store your
  used cooking fat, please visit our website thameswater.co.uk/binit.
  
  Challenges
  The wet weather has overwhelmed our sewer network with groundwater, surface water and flood
  water. It comes from many sources, including infiltration into our sewers and manholes, as well as
  those owned privately. It also enters our network from cross connected roof drainage.
  Because rainwater soaks into the ground slowly, groundwater levels can continue to rise long after
  the rain has stopped. This means it will take a long time for the extra water to leave our system, even once the rain stops.
  This water shouldn’t be in our sewers as they aren’t designed to hold it. Once they reach capacity, the water, mixed with untreated sewage, can cause floods and pollutions.
  
  What we are doing.
  We are cleaning these areas daily where our manholes have been overflowing, Oxford Street,
  Newbury Street, and a bridle path in Upper Lambourn. We are using tankers at the Upper Lambourn
  Sewage Pumping Stations 24 hours a day to help manage excessive flows in the sewers and have a
  filter unit on the footpath next to the Fire Station. This unit works by a pump feeding the water out of
  our foul sewer into the unit so it can be filtered and then safely discharged to the watercourse. We
  regularly monitor the River Lambourn to check for any impact, this monitoring has shown a minimal
  impact as it is heavily diluted by the groundwater and surface water. We regularly keep the
  Environment Agency updated on these results.
  We continue to investigate sources of groundwater and surface water which are entering our sewer
  system. This will include camera surveys and reviewing data from sewer monitors which have
  previously been installed in the sewers. This will help us prioritise locations for investigation.
  
  What we have done
  We have been a continuing member of the multi-agency Lambourn Valley Flood Forum since it
  started, keeping them updated on our many investigations and work completed in the Lambourn
  Valley. Over the years we have installed 10.1km of specialist leak tight liners in our sewers, and
  sealed 122 manholes in the Lambourn Valley sewer network, and have removed a private well
  connection to the foul water sewer in Upper Lambourn.
  More information can be found on our website, https://www.thameswater.co.uk/about-
  us/regulation/drainage-plans and select the Groundwater Impact System Management Plan for East
  Shefford.
  
  We’re here to help
  Our staff and contractors have been working around the clock for the last few months and whilst we
  appreciate that there is more to do, we are all trying our best and are committed to help improve the
  situation in Lambourn.
  If you have any questions, please call our 24-hour customer centre on 0800 316 9800 or email on
  customer.feedback@thameswater.co.uk quoting your address and reference number BB00469723.
  Thank you for your help to reduce the impact.
  
  Yours faithfully,
  Denise Kinsella
  Customer and Stakeholder Manager
  
  Below are images taken before a recent clean-up which was carried out by our team.
  If the sewer abuse stops below is what the road would look like, this is clear water and
  reduces the impact on the river.