Flooding and sewage in the Lambourn Valley – a solution in sight?

For the past two decades or so Lambourn has suffered from raw sewage leaks in the middle of the village and these seem to have been getting steadily worse. In 2020 the leaks started in early January and got so bad (as our video from 17 February 2020 shows) that they risked becoming a serious health hazard: also, the effluent drained into the SSSI-protected River Lambourn, one of the most environmentally protected waterways in the country. Similar problems were experienced along the Lambourn Valley and also in Aldbourne. The issue has been covered by Penny Post, Meridian TV and the Newbury Weekly News and is frequently discussed on the Lambourn Community FB group and at parish council meetings.

The Problem

The problem usually appears after periods of high rainfall and/or high ground water levels.

The sewers were built decades ago when the population of the village was a fraction of what it is today. Opinions differ as to what there main cause is: whether the sewers are are too small for Lambourn’s current population of 4,000; if groundwater is leaking in through cracks in the pipes; if excess surface water during storms is draining into the sewers (such as via manhole covers and surface water drains); if the pumps are inadequate; or if the problem is due to some combination of these and/or something else.

The most likely main cause is the volume of ground water and surface water getting into the sewers. Our chalk substructure holds ground water like a sponge, and the ground water is forced into the pipes through cracks in the pipes (so making the cracks worse). During heavy rainfall, surface water can drain into sewers as well. As more houses are built in the area, the volume and speed of surface water draining increases as there is less exposed land for surface water to soak into.

No solution has previously solved the problem. The result has been that the matter is dealt with each time by mitigating its symptoms (usually by sending a constant flow of tankers to syphon water and sewage out of the sewage system and take it downstream or further afield).

The Solution?

From February 2020, local ward member Howard Woollaston, local MP Laura Farris (who were only elected to their posts in May and December 2019 respectively), Lambourn Parish Council and other organisations and individuals intensified their efforts to find a solution. New impetus also came from Thames Water and regular flood forum meetings involving these groups.

As is common, the ground water levels receded during the late summer and autumn of 2020: so too, for most people, did the whole sewage problem. It is not a matter many think about unless they are literally confronted with it, as has happened all too often the the Valley.

However, it seems that Thames Water had not forgotten about the issue. On 4 December we received this communication from them which outlined what has happened and what still needs to be done. It’s to be hoped that these measures will make this winter and spring comparatively trouble-free. (Local ward member Howard Woollaston also covers this matter, and several others, in his latest monthly report, which you can read here.)

 

“We know winter flooding is a concern for many residents, and we’ve worked hard this summer to ensure high groundwater, which is at times prevalent across the Lambourn Valley, has minimal impact on our sewers. We’ve invested tens of thousands of pounds sealing and relining pipes to reduce groundwater leaking into them through cracks and joints and have also cleared the pipes of blockages. Our customers can play their part by not flushing wipes, nappies and sanitary products down their toilets, which account for most blockages we see in our pipe network and significantly increase flood risk.

“We’re working with the local authority, who are responsible for the management of groundwater and surface water and the Environment Agency, responsible for rivers, to understand what more can be done to keep the sewers clear to carry the wastewater they’re designed for without them being overwhelmed by groundwater or run off from rivers and roads.

“We have a specialist flow management team on standby in case of flooding to co- ordinate any tankers that may be needed throughout the Lambourn Valley to protect our customers from sewer flooding and will also use over ground pumps and the temporary filter we deployed last year if they’re needed.”

Lambourn

“We’ve relined sewers, including in Foxbury and Tubbs Close which we know are subject to groundwater flooding, to reduce the volumes of groundwater getting in through cracks and joins in the pipes. We’ve also sealed some manhole covers to stop surface water getting into the sewers through them and cleaned the sewers to remove any existing blockages. As a result we have maximum capacity available for the winter.

“The filter unit we used on Newbury Street last winter is already on standby so it can be deployed if needed. We’re exploring if there is somewhere else in the village to position the filter which will be less disruptive to residents while still being as effective.”

East Garston

“We plan to invest £30,000 relining sewers most at risk of groundwater flooding including in Font Street and Station Road. We’re waiting for a date to be granted for the work by the highways authority, as it will involve roadworks which are generally not permitted during December unless in an emergency. This work will therefore most likely happen in early 2021.”

Eastbury

“We’ve cleaned the sewers to remove any existing blockages and have sealed some manholes, so we have maximum capacity available for the winter.”

Great Shefford

“Issues here stem from surface water entering the sewers in large volumes. We’re in touch with the local authority and the Environment Agency to address this as surface water management isn’t the responsibility of the local sewage company.

“As some of the village sewers are connected by pumping stations, the work in we complete in Eastbury and East Garston will also help Great Shefford as this will remove some of the excess water which enters the village’s sewers.”

Emergency contact details

If you are aware of flooding or sewage issues, please see this section on Thames Water’s site for what to do and who to contact.

 

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