West to East Link Main Project – United Utilities By Steve Mackellar (Jacobs Engineering) and Ahmed Esat (United Utilities)
Large diameter, long distance aqueducts and pipelines do not arise very often and hence there is considerable interest in one of the largest pipelines being currently constructed for United Utilities. The £125 million West to East Link Main (WELM) project is the collaboration of United Utilities (UU), Jacobs Engineering, Montgomery Watson Harza (MWH), John Murphy & Sons (JMS), Atkins and Nomenca. It has been recognised for a number of years that inspection, cleaning and remedial works would be required on the large aqueducts feeding Liverpool and Manchester. Unfortunately, the aqueducts are so important that they cannot be taken out of service for long enough to undertake the work. Currently, Lake District water supplies Manchester via Thirlmere (TA) and Haweswater (HA) aqueducts, where the HA terminates at Woodgate Hill Service Reservoir (SR) in Bury. Lake vyrnwy water supplies Liverpool along the vyrnwy and Dee Aqueducts, terminating at Prescot Water Treatment Works (WTW).
n Regulatory Large Diameter Trunk Mains (LDTM) outage programme drivers – planned outages of the TA, HA and Dee Aqueduct for cleaning and maintenance. A lengthy period of optioneering settled on the solution to connect the Manchester and Liverpool systems together giving huge flexibility in the aqueduct network and allowing the required maintenance work to be undertaken. Separate systems are supplying water to Liverpool and Manchester with no flexibility in the system. There are several reasons why the WELM project is needed:
Begun in earnest in autumn 2006, UU teamed up with Jacobs and MWH to begin the lengthy and complex process of detailed optioneering and route selection.
n Key stakeholder undertaking outside of the Price Review process.
By early 2008 the outline route had been selected sufficiently for the Scope of Work to be drafted and contract documents prepared. By this stage the project estimate was established as around £125 million. In the summer of 2008 three tenderers made their submissions and the detailed evaluation commenced to determine the technical sufficiency and commercial benefits.
n Full support from OFWAT, Drinking Water Inspectorate, Environment Agency and Consumer Council for Water. n EU Directives / Policy (Habitats Directive, Water Framework Directive). n Impacts from Climate Change and safeguarding our future generations. n Security and Emergency Measures Directive (SEMD) – ability to maintain water supplies in the event of a major incident or attack.
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The diligence, skill and perseverance of the team is reflected in the fact that out of 55km of pipeline through this densely populated region, there is less than 1 km of it is along public highways.