Our last SAGLUV update was issued in November 2024. Two months seems a long time for a follow-up, but in truth, the situation hasn’t changed very much, which in some ways is a relief!
We said then that the impact of the various relining and repair works carried out by Thames Water during the summer and autumn, could not be fully assessed until the groundwater levels rose to cover the sewer pipes. Since November, those levels have been rising, sufficient for the EA to issue a groundwater flood risk alert, but not really high enough for a thorough test of the work. During the last few weeks the levels plateaued, but have just started to show a slight rise again, so no real test yet.
However, there are some positive signs! TW assure us that their monitoring, and comparison of data from previous years, has shown the 450m of relining and sealing work in Eastbury has reduced the ingress into the system. This has a positive effect, not only in Eastbury, where no sewer problems have been reported yet, but also down through the network in East Garston and Great Shefford. As stated above, it is difficult to assess the full impact until groundwater levels rise further.
But we have to be cautious. In East Garston there is still evidence of some groundwater ingress resulting in some higher than normal levels in the sewer, but generally, the pumping station is coping with it. There is however a problem when we get heavy rain and surface water run-off from roads and house roofs fill the part charged sewer pipes, leading to temporary backing up. The ATAC filter unit is installed ready to be switched on when necessary, but that hasn’t been needed yet, and the EA do not permit the unit to be used unless there is a spillage, or an imminent spillage that will go into the river.
To put it into perspective, in EG the groundwater level is already higher now, than it was in early winter 2023/24 when tankers had to be used, followed by the installation of the ATAC unit. So again, there is cautious optimism that we are in a better place than we were last year.
In Great Shefford, the flood alleviation Scheme is not yet complete, but a temporary solution will be in place to avoid the flooding that has been experienced in the past. It is hoped that this, and the relining work, will also help prevent the sewer flooding that was suffered last year. There have been no reports of problems yet.
SAGLUV Meeting with Thames Water/Lanes 13 December 2024
All of the above observations support the information that we were given at our meeting with Tessa Fayers, TW’s Director for Wastewater, Ty Harling, Operations Director for Lanes Contractors, and Jenny Pearson, the newly appointed Thames Valley Regional Manager, for TW.
TW confirmed that the planned relining and sealing work had been completed, and that regular follow-up inspections would made to assess the impact, and to look for other ingress points, as the water table rose.
At our previous meeting with the TW/Lanes team, we in SAGLUV had expressed our concern about the efficacy of some of the Lanes and other Contractors teams who were often the “face” of TW to customers. TW/Lanes committed then to return to the subject at this November meeting, and this they did. From their response, we believe that they have taken on board a number of the points we had made. We have certainly seen a lot more inspection and monitoring activity in our villages over the last month.
They explained that, each autumn, TW and Lanes draw up a very detailed “Winter Plan” that covers all aspects of the contract work to be carried out. This includes: the planned work, contingencies, resourcing, customer relations and communications, and many other relevant operational topics.
TW/Lanes shared the detailed content of this plan with us, some in confidence, and although it is common knowledge that TW are faced with severe financing challenges that impose limits on what can be done, we were left in no doubt that TW and Lanes have in place an extremely comprehensive plan that covers all foreseeable, and possibly unforeseeable, eventualities.
One of the most encouraging aspects that came out of it is that our upper part of the Lambourn Valley is very high on their list of priority areas, with several of our locations noted as “hot spots”. TW have told us this before, but to see it in black and white in an important planning document, certainly reinforces it. And the fact that this was the third meeting we have had with Thames Water’s senior director who is responsible for Wastewater throughout the whole of TW’s domain, including London, is also an indication of just how much focus they are putting on our small area. We are convinced that any failings that may occur this winter will be down to TW’s financial limitations rather than attention.
Lambourn Valley Flood Forum meeting 13 January 2025
The key points coming out of this meeting were:
· Groundwater levels are already past the threshold where TW would have expected to see some flooding problems prior to the relining and sealing work that was carried out in the villages during the summer and early autumn, but the levels are not as high as the peak of last year.
· Confirmation from TW that they are convinced that the work has had a beneficial effect and has helped to prevent sewer flooding. It has not been necessary for the ATAC filter units in Lambourn and East Garston to be switched on yet.
· Evidence of the improvements are seen at the pumping stations. For example, at East Garston SPS, in normal times with no sewer flooding, the pumps are expected to be working for about 3 hours a day, this week they are working for 7 hours a day. At the peak last year they were pumping 24/7 and still not coping.
· However, TW’s follow-up investigations and camera work have identified some sections in the relining that require slight modification to stop some ingress where the relining has been bypassed.
· They have also found a number of additional groundwater ingress points which will go onto the list for attention this summer. Some of these are in the main network, but some are in private drains, and TW will be discussing these with the property owners. TW have explained in the past that this relining and sealing work is an ongoing process as new ingress points develop, and are discovered, as repair work continues. The pressure of groundwater down at sewer level is enormous, and will continue to find weak spots in the network.
· TW acknowledge the point made earlier in this report, that with part charged sewers, any excessive rainwater getting into the network could cause temporary problems. This is something that TW will be taking into consideration in their planning.
· A bit further down the Valley at Weston, tankers are operating continuously and a number of infiltration points have been identified which will be tackled with relining this summer.
· Further to a point that was made by the SAGLUV representative at the last WBC Scrutiny Commission meeting, it was confirmed that there is now more regular communication and co-operation between WBC, EA and TW when attempting to address joint problems. If this continues, it will be a very positive development.
Now we just have to wait and see what is happening with groundwater levels. These are notoriously difficult to predict and we are seeking the latest forecast from the experts.
Fingers crossed for no significant increase, but we have to admit that hasn’t always worked in the past!
As always, please report any sewer or pollution problems to:Thames Water: Sewage and wastewater flooding | Contact us | Thames Water or 0800 316 9800
Environment Agency: Report an environmental incident - GOV.UK or 0800 80 70 60
And please also let your Village SAGLUV representative know as well so that we can follow it up with the relevant agency:
Eastbury: Andrew Gorton villagewardens@eastbury.org
East Garston: Martyn Wright martynwright345@btinternet.com
Great Shefford: Louisa Freeman greatsheffordpc@hotmail.com
Kind regards
Martyn Wright
SAGLUV
19 January 2025
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