Entec
Bulletin
Over the Hills and Far Away
Construction of the pumping station buildings used local
materials in keeping with other buildings in the area
In 218BC Hannibal may have taken a few elephants across the Alps, but now Northumbrian
Water has taken water over the Pennines, with more than a little help from
Entec.
The Hardedge Water Supply Project is a scheme to transfer potable water from Northumbrian Water's Wear Valley Water Treatment Works in County Durham to United Utilities customers in Alston, Nenthead and Garrigill, north east Cumbria, an area that had previously relied on natural springs for its water supply. It was the first 'cross border' supply carried out by Northumbrian Water, and saw the initiation of a commercial contract with United Utilities.
The project was driven by the need to improve water quality to the north east Cumbrian areas to ensure compliance with the EU Drinking Water Directive. It was also essential that the water supply be secure and able to meet the required flowrates at all times. A number of environmental issues needed to be addressed sensitively, as the project lay within the North Pennines Area of Outstanding Natural Beauty (AONB), with further conservation area and listed structure (bridges) challenges.
As project manager and designer, Entec liaised closely with Northumbrian Water, United Utilities, Wear Valley DC and Durham CC to finalise the agreed development and implementation programme. An important issue was the quality and availability of water from the Wearhead Water Treatment Works, which was already to be replaced with a major new plant. Construction of this works was programmed to run in parallel with the Hardedge project. The project required the optimisation of the transfer pipeline route from the waterworks to the supply area and the sensitive siting of three pumping stations necessary to deliver the flow over the hill. Additionally a reliable control system and implementation strategy were also essential, given the remote location and local sensitivities.
The buried pipelines were fully reinstated with the appropriate flora or hard surfacing, thereby ensuring that the character and qualities of the AONB were maintained. Construction of the pumping station buildings used local materials in keeping with other buildings in the area. Close liaison with English Nature and other environmental bodies enabled the pipeline route to take account of all conservation areas and issues. Agreements were also established with Durham CC to enable bridge crossings and public highways work to be completed to their satisfaction. This was significant, as the majority of the pipeline is located in the public highway (A689),the only highway along that part of Weardale, with only limited sections of the pipeline constructed in privately owned land.
The electrical supply to the final pumping station was the subject of much debate throughout the project. With the site being in the sensitive AONB, the approach for connecting the power supply was under scrutiny from several environmental bodies and local landowners. In this instance, a buried power supply was considered to be the preferred option, with great care required as the route was across 1.5km of moorland used for grouse shooting with a further 500m within the main highway.
The entire project comprised of 8.6km of pressure pipeline in County Durham with a further 8km in Cumbria. The three booster pumping stations were located at the Wear Valley Water Treatment Works, Lanehead, and at the Killhope Lead Mining Museum. The remote nature of these locations together with the incumbent long periods of inclement weather meant that it was essential that a secure communication and control system be established. Mobile and terrestrial phones are either non-existent or unreliable in these locations, so for the first time for Northumbrian Water and United Utilities, digital satellite communications have been used.
Despite the significant engineering challenges to be overcome
and the wide range of environmental, planning and public sensitivities,
the
project was completed
successfully and on time. So now the communities of Alston, Nenthead
and
Garrigill in the Cumbrian Pennines are the recipients of clean,
compliant and plentiful
water supplies. Hannibal would no doubt have been impressed.
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