- The scheme was to reconstruct an existing highway retaining wall following damage from a fallen tree. The retaining wall was supporting the highway on the banks of the river Sirhowy at Blackwood. The scheme required Natural Resources Wales flood consent as the majority of the work had to be done from within the water course.
The project required a number of wall types to be rebuilt to match the existing including dry stone, gabion and concrete reinforced walls tied into the bed rock. Several areas of the wall suffered from scour and required underpinning with underwater concrete.
Sirhowy river has proven to be extremely prone to spate, with the water levels rising quickly, water dropping back quickly and flooding being common. The local residents took a keen interest in the scheme due to the previous episodes of flooding. Our site team spent time with the residents to explain the works being undertaken. Good public relations were of paramount importance.
- During an initial site visit we identified an area of land where Japanese Knotweed was present. In order to avoid contamination spreading along the bank or further into the river, dendro scot membrane was laid under a temporary ramped access over the top.
It became clear there was an issue of silt, in order to contain this problem, silt curtains were installed, warning markers were placed, regular inspections were carried out, and water samples were taken.
During the initial phase of works, It became clear there was an issue of silt. In order to contain this problem, silt curtains were installed, warning markers were placed , regular inspections were carried out, and water samples were taken to ensure no change to the water quality.
- This project demonstrates Calibre Contracting’s ability to work with NRW and the local authority to complete a project along a challenging section of the river.
The project was successfully completed on programme
DURATION: 12 weeks
FORM OF CONTRACT: Nec3 Option B
CLIENT: Caerphilly County Borough Council
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The scheme was to reconstruct an existing highway retaining wall following damage from a fallen tree. The retaining wall was supporting the highway on the banks of the river Sirhowy at Blackwood. The scheme required Natural Resources Wales flood consent as the majority of the work had to be done from within the water course.