Thames Water raised a “Winter Event” due to a prolonged period of sub-zero temperatures and the subsequent thaw across the London area. The freezing conditions caused a significant increase in the volume of burst water mains. The leakage from these damaged mains potentially posed a significant risk to the health and safety of pedestrians and road users as well as a risk of damage to property and interruption to supply. 

Thames Water are obviously very keen to minimise any inconvenience to their customers; consequently we helped to bring the situation under control by mobilising up to 16 teams per day, some of which worked on through the night in freezing conditions.  

Amongst the many repairs that were carried out, the Event team were asked to repair a 1000mm strategic main in Finsbury. The leak on the main had started as a minor leak and became significant within several days. An assessment of the site conditions indicated that there was a need to decommission the main to enable excavation work to commence. 

The volume of water from the leak combined with poor ground conditions necessitated a closure of the main. As the main was strategic the shut down could only last for 24 hours before being recharged and re-commissioned.

The excavation was four metres deep, six metres long and three metres wide and was dug over a 48 hour period whilst the main was decommissioned and recharged.

The engineering team found that the leak was caused by a failed joint on the 1000mm pipe; J Brownes engineering team worked along side UTS to install a bespoke encapsulation collar and repair the leak.

Over the period of the Event the J Browne team managed several hundred NRSWA notices/permits and associated repairs to the burst mains.  We were able to utilise our in-house Traffic Management resource for many of the burst repairs carried out in the more ‘challenging’ locations.  Also our in-house reinstatement teams managed to ensure that we were able to carry out first time reinstatement on all the repairs unless there was an operational requirement that dictated otherwise. 

Throughout this period the team built a strong working relationship with the Thames Water network managers and supporting NST’s whilst co-ordinating the works and ensuring the network was brought back under control with the minimum of inconvenience to the Thames Water customers.