• Castlehaven
    coastal protection scheme

  • Isle of Wight, UK

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siphon drain photo

Siphon drain outlet

manhole photo

Manhole installation

siphon drain

Components of a siphon drain system

Client
Isle of Wight Council
Main contractor
High Point Rendel
Drain installation subcontractor
TJ Brent Ltd
Siphon and pneumatic pumping system supplier
TP Geo
Wells and instrumentation subcontractor
WJ Groundwater Ltd

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The site is located on the southern side of the island within an area prone to coastal erosion and landslips. The project involved the installation of a system of 150 siphon and electro-pneumatic wells designed to reduce the groundwater level sufficiently to promote stability of the slope. WJ carried out the installation of the wells and an extensive array of instrumentation to monitor the system. The instrumentation included observation wells, vibrating wire transducers (in wells and piezometers) to monitor groundwater levels, inclinometers to monitor ground movement, open channel flow-meters and a weather station. Monitoring was automated using multichannel dataloggers which recorded and transmitted the data and any alarm conditions to a control centre. WJ carried out long-term monitoring on the site for a period of 15 months.

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Key words

  • slope stability, green sand, Gault clay, electro-pneumatic wells, siphon wells