After 9 months of intense work starting in October 2021, the Crantock Rising Main scheme was completed in July 2022, in collaboration with our client South West Water, to improve and maintain the wastewater network in the Crantock and Newquay area.
Initially, Glanville began undertaking Rising Main replacement and rehabilitation work around 5 years ago under a design and build mechanism. Rising Mains are wastewater pressure pipes that come with added design and construction constraints over and above gravity sewer work that Glanville undertakes. Having replaced circa 20,000m of rising main pipework for SWW in recent years from The Lizard and Mousehole to Awliscombe and Plymstock, we could see that our knowledge and training were suited to carry out this project from start to finish.
Following many discussions and optioneering with the client's Core Project Team, Crantock became a traditional open-cut pipeline project. The key factor here was re-routing the existing main away from crossing critical geographical areas (namely the Gannel Estuary), and re-direct flows directly into Newquay Sewage Treatment Works.
The scheme consisted of approximately 1150m of 355mm HPPE rising main, approx. 2.5km of 400dia gravity sewer, and 600m of syphon sewer. Considerable liaison works with landowners, Parish Councils, Local Highways, and SWW Operations have been undertaken.
A route for the new pipeline was sought that minimised disruption to key ecological areas, minimised disruption to the public, and provided a practical and constructable route that would be cost-effective and provide the required output. Utilising Glanville Geospatial, we undertook a full in-house topographical survey of the proposed route to assist the design process, as well as other ecological surveys to help give an overview of potential obstacles.
The timings of the 9 road crossings on the project became the critical path for the programming of the scheme, and the project required extensive coordination between landowners, land agents, and the local councils and businesses to ensure that the works caused minimal disruption and were carried out as efficiently as possible.
Pipelaying works finished in July after which the rising main was commissioned with the new pumps, and the reinstatement and demobilisation of the site were completed. Follow the link below for a birds-eye view of the site when in construction, and to see the scale of this flagship project for us working with our key client South West Water.