Update on Thames Water Pumping Operations

The Parish Council has regularly contacted representatives at Thames Water (TW) to complain about the noise and disturbance that is caused by the tanker operations at the pumping station in Dry Lane. The good news is that there may be an end to overnight pumping by the tankers.

Background situation

The sewers through the village are letting in groundwater. This increases the volume of foul water that runs through to the pumping station in Dry Lane. The pumps in the pumping station are unable to cope with the increased volume and so the tankers are removing the excess (up to 2,400 gallons per day in the wettest period).

TW are working on a scheme to repair the sewers and stop the groundwater getting into them. When the repair is done, the tanker operations will stop.

Tanker operations

Tankers have been operating in Crawley every winter for the last three years. Each year, as the weather improves and the ground water levels drop, the problem at the pumping station goes away and tanker operations can be halted.

Currently the tankers are operating on a 24hrs/day regime. However, as the ground begins to dry out, we are reaching a point where TW may be able to reduce the number of tankers. On 25th March 2021 the TW manager who is responsible for the tanker operation gave an undertaking that he would change from 24hr working to daytime only working (6am to 6pm). They will stop the night-shift (6pm to midnight to 6am). TW advise that this change in routine will begin on 26th March 2021.

TW did make it clear that tankers will return immediately if the levels in the pumping station begin to increase. If this is found to be necessary, it might be possible to operate an 18hrs/day regime and not to have to return to 24hrs/day.

Sewer repairs

In the longer term, works to rebuild the sewers that run under Foxburrow Lane should provide a permanent solution. This repair would stop groundwater from getting into the sewers and the pumping station would then cope with the volume of sewage in the village without the need of tankers to take away the excess. TW are getting prices to carry out the work but it will be a big engineering job that will require ground water lowering to enable TW to access and rebuild the sewers (that will be expensive!).

Parish Council

The PC view is that TW have recognised the need to rectify the problem and are taking active steps to do something about it. However, the best we can expect is that these works will be undertaken during the summer and that tankers will not have to return through the autumn and winter of 2021.

Please contact Mark McCappin via mark.mccappin@crawleyvillage.org.uk if you have any questions.

Thames Water Pumping Operations in Dry Lane

The Parish Council has been in contact with Thames Water to follow up on what is going on with their operation of the foul sewer system in the village. Tankers have been operating at the pumping station in Dry Lane for many weeks causing problems with noise, traffic congestion and damage to the verge.

Thames Water have advised us that the problem in Crawley is due to ground water entering the foul sewer network. The tankers are required because the pumping station cannot cope with the amount of flow – the foul system was not designed to take any surface or ground water so it cannot cope with the volume that is finding its way into the pumping station.

As a solution to the problem, Thames Water arranged for sections of the sewers to be lined. This would stop excess water getting into the sewers and the pumps in the pumping station would then be able to manage without the addition of tankers to take excess foul sewer material away.

The lining process involves inserting a sleeve inside the existing sewer. The sleeve is inserted with what is essentially a heavy duty balloon, the balloon is inflated and this causes the liner to form the shape of the sewer and stop the ingress of water. Once the resin in the sleeve has dried, the balloon is deflated and removed.

However, when TW attempted this work, they found that the pipes were cracking under the internal pressure from the balloon. Ground water has washed away material from around the outside of the pipes which allows the pipes to break.

TW have not had this issue before in any of the locations where they have carried out this type of work. They were forced to stop the lining to prevent a total failure as this would involve an almost impossible task of trying to control the ground water within the excavation and would have meant a long road closure just to fix the one issue.

TW now need to find a different approach to this issue and unfortunately they will need to carry on with the tankering until the levels within the sewer have subsided. We have asked them to limit the tanker operations to daytime as far as possible to minimise the noise and disturbance that is being caused to Crawley residents and they have given us an assurance that they will try to do this.

Patch Lining Map
Map showing Thames Water sewer patch lining attempt in December 2020