Sevenoaks strategic water main Customer information pack December 2018 Author: South East Water South East Water Rocfort Road Snodland Kent ME6 5AH 0333 000 2244 Customer information pack | December 2018 Introduction Dear customer, Thank you very much for your interest in plans to lay a new water pipe in Sevenoaks. This information pack contains copies of the information on display at the drop-in session and answers some frequently asked questions about our plans. We hope we have been able to answer all your questions, but if you need more information or would like to provide feedback on the project, you can do so using the contact details at the end of this document. As our plans progress, we will contact customers again through letters, the local councils and the press. Our dedicated website page, corporate.southeastwater.co.uk/Sevenoaks will be kept up to date throughout the project and you can follow us on Facebook and Twitter @sewateruk for general news and updates. Yours faithfully, Ben McKellar Project Manager Page 2 of 16 Customer information pack | December 2018 Project background The existing 12-inch diameter cast iron water main, which runs through Sevenoaks High Street, is at full capacity. Population growth means that parts of the town will have no drinking water or low tap water pressure every day during peak times (7am – 9am, 5pm – 7pm) within ten years. There is also a risk the existing pipe could burst if it is pushed beyond its design limit. We have already strengthened the water main feeding Sevenoaks directly from Cramptons Road Water Treatment Works along the A225 between the junctions with the A25 and Bradbourne Road. We now need to lay a new pipeline from our Solefields treated water storage reservoir to the junction of Dartford Road and Avenue Road to ensure we can feed more water into the town to meet the daily demands during peak periods into the future. Four route options are being investigated for the new main, all of which require us to connect the new pipe into the existing wider network in the A225. It is the installation of this new water main which we are consulting on. We are consulting with a range of stakeholders, local interest groups and residents over the proposed routes. Through our discussions, we hope to understand the impact each route would have and the factors which could help us to rule each option in or out. When our consultation ends we will develop our final plans, taking all feedback into account along with a range of factors, including socio-economic, environmental, cost, duration of work, technical difficultly, traffic management required and more. In a separate project, we are expanding the capacity of our Solefields storage reservoir to feed the growing population and reinforcing a 21 metre length of an eight-inch diameter water main along Tonbridge Road (near Sevenoaks School) to protect local water pressures when a new hotel is built in the town. This work is currently planned to take place in the school summer holidays of 2019. We will write to affected customers about this separately. Page 3 of 16 Customer information pack | December 2018 Route options Page 4 of 16 Customer information pack | December 2018 Comparison of the key factors affecting each route Knole Park and Sevenoaks School High Street East of Knole Park local roads and Knole Park Cost (excluding £3.9 million £2.2 - £3.2 million £1.9 - £2.8 million £7.5 million compensation) Pipe length 1.8 kilometres 3.9 kilometres 3.6 kilometres 9.5 kilometres Work duration Up to 10 years Within one year Potentially two years Up to five years Traffic Lane closures / Traffic lights on Traffic lights on A225, Road closures on Seal management road closures on A225, Hollybush Hollybush Close and Hollow Road, St Julians A225 Close and Avenue Avenue Road Road, Park Lane and Road Blackhall Lane. Traffic lights on A225. Environmental Listed buildings. Within a SSSI but Within a SSSI but the Listed buildings and Potential the special special features will potential archaeology. archaeology. features will not be not be impacted by Partly within a SSSI but impacted by work. work. Potential special features won’t be Potential archaeology. impacted. archaeology. Socio- Busy high street, Knole Park would Use of rugby pitches Increased congestion economic heavy commuter stay open maybe restricted at and pollution in other traffic, throughout, the school for one parts of town during road independent minimal disruption. year. Little impact on closures. Access to shops impacted Knole Park. various schools affected. Technical Lots of other Ground Ground investigations A larger pipe and difficulty utilities in the investigations needed to confirm additional pumping ground to weave needed to confirm viability. stations needed due to the pipe around viability, however, the pipe length. we already have an 18 inch main in this part of the park Page 5 of 16 Customer information pack | December 2018 High Street The proposed route is between Solefields Service Reservoir opposite Sevenoaks School and the junction of Dartford Road and Avenue Road via Tonbridge Road (A225), High Street and Dartford Road. Page 6 of 16 Customer information pack | December 2018 Knole Park and local roads This proposed route is through Tonbridge Road (A225), Knole Park, underneath Seal Hollow Road then along Hollybush Close and Avenue Road. Page 7 of 16 Customer information pack | December 2018 Sevenoaks School and Knole Park This proposed route is through Tonbridge Road (A225), Sevenoaks School and Knole Park, underneath Seal Hollow Road then along Hollybush Close and Avenue Road. Page 8 of 16 Customer information pack | December 2018 East of Knole Park This proposed route would see the main laid south along Tonbridge Road (A225) from Solefields Service Reservoir, along St Julian Road, on to Park Lane, Back Lane, Blackhall Lane, along Seal Hollow Road, Vine Court Road and Avenue Road. Page 9 of 16 Customer information pack | December 2018 Areas at risk of low pressure or no water due to development 2013 Page 10 of 16 Customer information pack | December 2018 Summer 2020 Risk of little to no water at times of peak demand Risk of low pressure at times of peak demand Pressures acceptable at times of peak demand Page 11 of 16 Customer information pack | December 2018 Additional 600 properties at Sevenoaks Quarry site (in the Local Plan) Page 12 of 16 Customer information pack | December 2018 FAQs Where does Sevenoaks get its water from currently? A 12-inch diameter cast iron water main in Sevenoaks High Street takes water from Cramptons Road Water Treatment Works into town and to Solefields Reservoir. Once this new pipe is installed, we will supply water into Sevenoaks at peak times both directly from the treatment works and also from the reservoir. The existing 12-inch diameter main will stay in operation, and be supported by this new pipe. How does the new pipe work to support water pressures in the town? Overnight, Cramptons Road Water Treatment Works pumps water to Solefields and Riverhill service reservoirs (underground, treated water storage tanks holding millions of litres). Then in daily peak demand we will use gravity to feed the town again. Pumps alone are not viable because there is a time delay and therefore cannot respond instantly to changes in demand. If you don’t lay the pipe, when will Sevenoaks have low pressure/no water? Within ten years. We expect to supply all our customers with 15 metres pressure at the boundary valve but our legal minimum is 10 metres. What are your legal obligations? We have the obligation to supply clean water to anyone who requests it at a reasonable pressure and to connect new developments to our water supply. Under Ofwat, we have the legal obligation to invest customers' money wisely and maintain an efficient water network. Who gives you permission to lay new pipe? The Water Industry Act 1991 gives us permission to lay new pipelines in private land, however, we prefer to gain consent from the land owners. The New Roads & Street Works Act gives us permission to lay in roads, however, Kent Highways can dictate conditions of our work, such as timings. Natural England give their Assent to our works that would affect environmentally protected areas. Where does the money come from to lay new pipes? It is funded by bill payers, as set out in our five-yearly business plans which are approved by Ofwat. Our latest draft plan was published in September and is currently with Ofwat for review. We expect to hear the conclusion of Ofwat’s review in the New Year. How large is the new water main (diameter)? 300 mm (12inches) in diameter. Water mains are usually laid around 90cm underground, depending on ground conditions, underneath all other utilities with the exception of sewers. What engineering method(s) do you plan to use? We need to do ground investigations to find out what the soil is made of and its physical properties on each route option in order to choose a method, but generally speaking we use three techniques: Horizontal Directional Drilling – We dig a series of pits around 100 metres apart, use a drilling rig to create a large enough tunnel underground which we can then pull the pipe through. This is a quicker way of installing long lengths of pipe with minimal disruption to the ground Page 13 of 16 Customer information pack | December 2018 surface, however can only be used within certain soil types, such as clay. It is also laid significantly deeper than other methods which can create maintenance issues. Open-cut – We remove the top layer of ground, and if it is grassland or similar, we remove the topsoil and store it safely.