Portland Seawater Outfall (Chesil Beach)

Project: Portland Storm Interceptor - Investigation & Cathodic Protection 
Client: The Environment Agency

The project:
Portland Storm Water Interceptor is a 540m long reinforced concrete Seawater defence channel that is buried under the Portland section of Chesil Beach on the Jurassic Coast in Dorset. The interceptor was constructed during the mid-80s after it was decided that an effective long-term solution was required to alleviate flooding that had occurred in the past, cutting Portland off from the mainland & resulting in the death of up to 60 people in the storm surge of Nov 1824.

The solution: 
The Interceptor is required to remain in service indefinitely, which makes the maintenance of it’s condition critical in order to serve it’s purpose. APA Concrete Repairs Ltd were commissioned to undertake a series of investigations & concrete testing works in order to establish the condition inside the reinforced concrete channel. APA’s specialist ICorr & confined space trained technicians extracted concrete cores, took corrosion rate readings, mapped half-cell potentials, tested for carbonation & Chlorides etc. to help determine the state of the structure. Under a separate scheme, APA installed a Cathodic Protection system & concrete repairs on the Interceptor Outfall, in order to prolong it’s serviceable life.


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