Strawberry Line Update – 5 April 2018

As part of our Southern Resilience Scheme, which reinforces the water supply to 280,000 customers across North Somerset, the Strawberry Line Cycle Way is currently diverted in the Winscombe area. This includes a diversion around Shute Shelve Tunnel.

We are aware of the significance of the tunnel to the local area and our intention had been to reopen the tunnel for the summer of 2017. Unfortunately reinstatement of the path has been delayed and, following discussions with the Strawberry Line Management Committee and North Somerset Council, the route will remain on its temporary diversion until further notice. Construction of the pipeline within the tunnel has been completed, and the security of the water supply to 280,000 customers has been accomplished.

When the works began in October 2016, there was a minor rock fall within the tunnel. Therefore, work had to be suspended whilst a full investigation into this event took place and a safe plan to carry out the work was devised.

We have made significant improvements to the safety netting to ensure the tunnel’s ongoing safety once our work has been completed. Unfortunately our work on the safety netting had to be suspended due to the presence of roosting bats.

We worked with Natural England and North Somerset Council on measures to prevent bats from roosting in the tunnel whilst works were on-going, but the measures were not effective. The Strawberry Line and tunnel habitats are important sites for bats and many other species of flora and fauna; therefore, we are endeavouring to minimise our impact on the natural environment. We wish to leave it in a condition that is as good, if not better, as when we started.

The on-going environmental issues resulted in a decision to complete as much of our works as possible before the bat hibernation period began in October. The decision to keep the tunnel diverted throughout the summer holidays was not taken lightly.

Protection of stalagmites/ stalactites: There are some quite rare examples of mineral formations in the tunnel. We have implemented protection measures where the most significant examples have been enclosed in timber shutters during the construction programme.

Protection of cave spiders: The tunnel also provides an ideal habitat for cave spiders whose welfare needs to be considered. The most prominent locations were protected with shuttering but ventilation was maintained.

Winscombe – The Latest

The work to lay the pipe has been completed. Permanent reinstatement of the Strawberry Line will be undertaken as and when ground conditions improve.

How did we pick this route? 

The route of the main was selected from a short list of options. The scheme has been designed with the impact on the environment and customers at the forefront as well as trying to find the best engineering solutions. There were many obstacles in the way including the airport, many ancient woodlands and of course the Mendip Hills, which have to be avoided, restricting the possible route options. The final route also minimises the impact on the major commuter routes such as the A38 and A370.

One of the biggest engineering accomplishments of the scheme is the ability to use gravity, rather than pumping, to transfer water from Barrow  to Cheddar. This dramatically reduces energy usage and means the pumping station in Barrow Gurney did not need to be upgraded. This also keeps the running costs of the main lower now that it is in operation.

The impact on the environment was at the centre of the design work. The area is rich in biodiversity ranging from Dormice, Great Crested Newts, Bats as well as a range of plant life. Bristol Water aim to leave all sites affected by the project in a better environmental state than at the start. To do this, we have designed a Biodiversity Index Score system, which was trialled at a number of schemes between 2010 and 2015, including the construction of the Millmarsh Reservoir near Frome. The scheme won a Green Apple Award in 2015 for environmental best practice. Any hedges removed during the scheme were kept to 7m gaps where possible as to not disrupt bat navigation routes.

Axbridge and Cheddar – The Latest

Exactly what is happening between Axbridge and Cheddar?

The main leaves the Strawberry Line Cycle Way by Shute Shelve Tunnel and heads across the A38. The pipeline then heads over Cross Lane before starting to follow the A371 for 1.2km. Unfortunately, we could not lay the main in the verge of the A371 as there are already gas mains there. Therefore, the main has been laid in the carriageway. The permanent reinstatement of the road surface is scheduled to take place from the end of April and should be completed by mid-May.
The pipeline heads back into fields before following the Strawberry Line Cycle Way by Cheddar Reservoir. A safe diversion of the cycle way is in place. The main then heads into Cheddar Treatment Works where it connects to the pumping station.

How did we pick this route? 

The route of the main was narrowed down from eight possible options. The scheme has been designed with the impact on the environment and customers at the forefront as well trying to find the best engineering solutions. There were many obstacles in the way including the airport, many ancient woodlands and of course the Mendip Hills which have to be avoided, restricting the possible route options. The final route also minimised the impact on major commuter routes such as the A38 and A370.

One of the biggest engineering accomplishments of the scheme is the ability to use gravity, rather than pumping, to transfer water from Barrow  to Cheddar. This dramatically reduces the energy usage and means the pumping station in Barrow Gurney does not need to be upgraded. This also keeps the running costs of the main lower now that it is in operation.

The impact on the environment has been at the centre of the design work. The area is rich in biodiversity ranging from Dormice, Great Crested Newts, Bats as well as a range of plant life. Bristol Water aim to leave all sites involved in the project in a better environmental position than at the start. To do this, we have designed a Biodiversity Index Score system, which was trialled at a few schemes between 2010 and 2015, included the construction of the Millmarsh Reservoir near Frome. The scheme won a Green Apple Award in 2015 for environmental best practise. The hedges removed during the scheme were restricted to 7m gaps where possible as to not disrupt bat navigation routes.

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